Title of Invention

"A COKE DRY QUENCHING METHOD"

Abstract A coke dry quenching method that uses a quenching tower comprising a quenching chamber and a prechamber on top thereof, comprises of the steps of charging red-hot coke from above the prechamber, injecting air and/or water or steam into the prechamber, exchanging heat with the sensible heat of the red-hot coke by using an inert gas as a medium in the quenching chamber and recovering heat in the Form of steam in a waste-heat boiler, characterized by; setting the ratio of the adjusted quantity of water or steam injected into the prechamber to the adjusted quantity of air injected into the prechamber so that a constant temperature is maintained in the prechamber, supplying air to the high-temperature gas discharged from the quenching tower before the gas reaches the waste-heat boiler, setting the ratio of the adjusted quantity of air supplied to the high-temperature gas before reaching the waste-heat boiler to the adjusted quantity of air injected into the prechamber and water or steam injected into the prechamber so that the concentration of the combustible gas and oxygen in the circulating gas is maintained constant, adjusting the quantities of air injected into the prechamber and/or water or steam injected into the prechamber and air supplied to the high-temperature gas before reaching the waste-heat boiler so that the quantity of heat input to the waste-heat boiler is maintained constant, and correcting the target value for the heat input to the waste-heat boiler so that the quantity of the steam generated in the waste-heat boiler becomes equal to the target value.
Full Text The present invention relates to a coke dry quenching method.
Technical field

The present invention relates tyo coke dry querching method and coke dry quencher,

Bachkground art

A coke dry quencher (CDQ) is used for achineving energy conserevation by recovering the swensible heat of red-hot coke that is cooled when discharged form coke ovens,

A coke dry quencher comprises a quenching chember where the wsensible heat of red-hot coke is exchanged by using an inert has and a prechamber disposed above the quenching chamber red-hot coke is change into lkthe prechamber from above the prechamber is provided to absorb the variation in red-hot coked charging times and realizeoperation stabilization.

After exchanging heat with inert has and quenched clsoed to 200 C in the quenching chember, coke is discharged in given quantities. The inert has heated to 900 C after the heatr exchange is discharged from the upper part of the quenching chember to the ringh duct and deliverd through the primary dust catcher to the waste-heat doiler where heat is reovered and then back to the quenching chamber under pressure applied by the circulating blower.

The coke charged in contains volatile substances and coke fines being highly combustible, volatile
substances are likely, when contained in circulatingases im high percenages to give rise to abnormal
combustion the volatile substances and coke finesremaining in coke lumps can be burnt if air is injected
in the prechamberThe injected air sometimes burns part of the surface
layer of red-not coke mixing of the air and waste gas

of combustion thus heated to high temperatures with the inert gas increases the heat release of the gas discharged from the quenching chamber.
Because the temperature of the coke arriving at the quenching chamber via the prechamber is also raised, the
quantity of heat collected by the inert gas in the quenching chamber also increases. As a consequence, the quantity of steam colZected by the waste-heat boiler increases.
The air injection into the prechamber not only increases the quantity of heat recovered in the waste-heat boiler in steady-state operation of the dry quenching system, but also keeps the quantity of heat recovery in the waste-heat boiler invariant even when the coke temperature in the quenching chamber drops as a result of a decrease in the supply of red-hot coke or a drop in the temperature of red-hot coke. Japanese Unexamined Patent Publication (Kokai) No. 61-37893 discloses a method for injecting air into the prechamber.
Japanese Unexamined Patent Publication {Kokai) No, 59-75981 discloses a method for supplying a moistened gas into the prechamber in the dry quenching system, producing a gas containing large quantities of carbon monoxide and hydrogen by the reaction of the gas with red-hot coke, and mixing the produced gas with the circulating gas in the quenching tower.
It is stated that the carbon monoxide and hydrogen gas recovered as components of the circulating gas can be recovered as fuel gas after passing the boiler or as steam in the boiler after burning carbon monoxide and hydrogen by adding air into the gas duct.
Generally, the steam generated in the waste-heat boiler of the coke dry quenching system is often converted to electric energy the steam turbine generator. In order to stably run steam turbine generators at the most efficient point, it is important to maintain the steam generation by the waste-heat boiler at the required
constant level.
If generation of steam used for general purposes varies with respect to the requirement, steam falls short of the requirement when generation decreases and exceeds the requirement and is wastefully dissipated when generation increases. In order to ensure effective use of generated steam, it is necessary to maintain steam generation, at a constant level.
The presence of the air injected into the prechamber, the water and steam injected into the prechamber and the air injected into the high temperature gag recovered from the quenching tower increases the quantity of gas circulated between the quenching tower and waste-heat boiler. In order to maintain the quantity of the circulated gas at a constant level, it is necessary to let off part of the circulated gas to outside.
If the circulating gas contains unburnt gases such as carbon monoxide and hydrogen, it is difficult to effectively recover the energies of such unburnt gases.
It is therefore preferable to ensure that the circulating gas contains no unburnt gases at least when the circulating gas has passed the waste-heat boiler by converting the unburnt gases contained in the circulating gas to heat energy by burning with injected air.
The oxygen contained in the circulating gas is unfavorable because it burns coke in the quenching chamber and lowers the quenching ability thereof. When injecting oxygen into the circulating gas recovered from the quenching tower, it is therefore necessary to ensure that oxygen remains in the circulating gas by injecting an excessive amount of oxygen.
The temperature in the prechamber rises when part of the residual volatile substances, coke fines and coke lumps are burnt by injecting air into the prechamber. When the temperature in the prechamber reaches approximately 1400 °C, the ash in coke is melted and

gasified and the gasified ash is carried with the air and mixes with the inert gas ascending in the quenching chamber.
Since the temperature of the inert gas at the exit end of the quenching chamber is approximately 900 °C, the gasified ash coagulates and adheres to sloping flue in the upper part of the quenching chamber. This accretion is called clinker, clogs the gas flue, increases the flow resistance of gases, and impairs the circulation of the hot coke quenching gas.
Therefore, it is necessary to constantly control and maintain the temperature in the prechamber below a certain level even when air is injected into the prechamber.
In order to meet the above requirement, the temperature of the gas supplied to the waste-heat boiler must be varied. The upper limit of the service temperature for the boiler tubes constituting the waste-hear coiler, however, is specified depending on the material and structure thereof. Since the use at a temperature above the specified upper limit leads to thermal fracture, it is necessary to keep the temperature of the gas supplied to the waste-heat boiler below the specified limit.
If the temperature of the gas supplied to the waste-heat boiler drops, the heat exchange efficiency of the boiler drops, with a resulting decrease in steam production. Therefore, it is necessary to constantly control the temperature of the gas supplied to the waste-heat boiler within a certain range.
The high-temperature waste gas discharged from the quenching tower is supplied to the waste-gas boiler via the sloping flue. If the quantity of the waste gas exceeds the upper limit, coke floats and bursts from the sloping flue. The bursting coke causes a sudden increase flow resistance of the circulating gag and wears away or damages the boiler tubes. Therefore, it is necessary to


control the flow rate of the high-temperature waste gas below a certain level.
In order to achieve energy saving by maximizing the recovery of sensible heat from the red-hot coke in the quenching chamber, it is important to increase the supply of inert gas to the quenching chamber as much as possible. Because the upper limit of the waste gas from the quenching tower is set as described earlier, it is necessary to constantly control the supply at the upper limit. [Summary of the Invention]
A first object of the present invention is to provide, in the coke dry quenching method to recover the sensible heat of red-hot coke as steam by using the coke dry quencher, a quenching method to invariably maintain the recovery of steam at a required level. A second object of the present invention is to provide a quenching method to maintain, the quantities of combustible gas and oxygen in the circulating gas at a minimum level. A third object of the present invention is to provide a quenching method to prevent the accretion of foreign substances in the sloping flue by maintaining the temperature in the prechamber below a certain level. A fourth object of the present invention is to prevent heat fracture of boiler tubes and lowering of the heat recovery efficiency of the boiler by maintaining the temperature of the gas supplied to the waste-heat boiler within a certain range* A fifth object of the present invention is to prevent an increase in the flow resistance of the circulating gas and the wear and fracture of boiler tubes by the floating and bursting coke and maximize the recovery of sensible heat from red-hot coke in the quenching chamber by invariably maintaining the flow rate of waste gas from the quenching tower at a constant level.
A sixth object of the present invention is to provide a coke dry quenching method and coke dry quencher

that do not form an accretion of clinker even when air is injected into the precharaber and combustible gases and coke fines are burnt to enhance safety and increase waste heat recovery.
(I) The gist of the present invention to achieve the first to fifth objects described above is as set out below:
(1) A coke dry quenching method that uses a
quenching tower 1 comprising a quenching chamber 2 and a
prechamber 3 on top thereof, comprises the steps of
charging red-hot coke 9 from above the prechamber,
injecting air and/or water or steam into the prechamber
3, exchanging heat with the sensible heat of the red-hot
coke by using an inert gas as a medium in the quenching
chamber and recovering heat in the form of steam in a
waste-heat boiler 7, the method is characterized by
adjusting the quantity of air and/or water or steam to be injected into the prechamber 3 so that the quantity of heat input into the waste-heat boiler becomes equal to the target value.
(2) The method described in (1) above, in which the
ratio of the adjusted quantity of water or steam injected
into the prechamber (hereinafter referred to as the "PC
water-steam 26") to the adjusted quantity of air injected
into the prechamber (hereinafter referred to as the "PC
air 24") is set so that a constant temperature is
maintained in the prechamber.
(3) The method described in (1) or (2) above, in
which air (hereinafter referred to as the "SF air 25") is
supplied to the high-temperature gas 22 discharged from
the quenching tower 1 before the gas reaches the waste-
heat boiler/ the quantities of the PC air 24 and/or PC
water-steam 26 are adjusted so that the quantity of heat
input to the waste-heat boiler is maintained constant,
and the ratio of the adjusted quantity of the SF air 25
to the adjusted quantity of the PC air 24 and/or the PC
water-steam 26 is set so that the concentration of the

cotnfoustible gas and oxygen in the circulating gas is maintained constant.
(4) The method described in (1), in which adjustment is done so that the quantity of the
steam generated in the waste-heat boiler, instead of the
quantity of heat input into the waste-heat boiler/
becomes equal to the target value.
(5) The method described in (I), (2) or (3) above,
in which adjustment is done so that the gas temperature
at the entry end of the waste-heat boiler, instead of the
quantity of heat input into the waste-heat boiler,
becomes equal to the target value,
(6) The method described in (1), (2), (3) or (5)
above, in which the target value for the heat input to
the waste-heat boiler or the gas temperature at the entry
end of the waste-heat boiler is corrected so that the
quantity of the steam generated in the waste-heat boiler
becomes equal to the target value.
(7) The method described in any of (1) to (6) above,
in which adjustments of the PC air 24, PC water-steam 26
and SF air 25 are done so that the quantity of heat input
to the waste-heat boiler is maintained constant by
detecting variation in the quantity of the coke 10
discharged from the quenching tower 1 and compensating
for variation in the quantity of sensible heat recovered
from coke due to the detected variation in the quantity
of coke discharge.
(8) The method described in any of (1) to (7) above,
in which adjustments of the PC air 24, PC water-steam 26
and SF air 25 are done so that the quantity Of heat input
to the waste-heat boiler is maintained constant by
detecting variation in the quantity of the circulating
gas 37 and compensating for variation in the quantity of
sensible heat recovered from coke due to the detected
variation in the quantity of the circulating gas.
(9) The method described in any of (1), (2) and (4)
to (8) above, in which air (SF air 25) is supplied to the

high-temperature discharge gas 22 from the quenching tower before the waste gas reaches the waste-heat boiler 7 and adjustments of the PC air 24 and PC water-steam 26 are done so that the quantity of heat input to the waste-heat boiler becomes equal to the target value by detecting variation in the quantity of the SF air and compensating for the variation in the quantity of heat input to the boiler due to the detected variation in the quantity of the SF air.
(10) The method described in any of (1) to (9)
above, in which part of the gas discharged from the
waste-heat boiler 7 and supplied to the quenching chamber
2 is bypassed, the bypassed gas (hereinafter referred to
as the "bypassed gas 29") is merged with the gas supplied
to the waste-heat boiler, and adjustments of the PC air
24, PC water-steam 26 and SF air 25 are done so that the
quantity of heat input to the waste-heat boiler is
maintained constant by detecting variation in the
quantity of the injected gas 21 supplied to the quenching
chamber and compensating for variation in the quantity of
sensible heat recovered from coke due to the detected
variation in the quantity of the injected gas 21 supplied
to the quenching chamber.
(11) The method described in any of (1) to (10)
above, in which when the detected temperature of the gas
supplied to the waste-heat boiler exceeds the
predetermined upper or lower limit the gas temperature at
the entry end of the boiler is brought back to between
the upper and lower limits by increasing or decreasing
the flow rate of the circulating gas,
(12) A coke dry quenching method that uses a
quenching tower 1 comprising a quenching chamber 2 and a
prechamber 3 on top thereof, comprises the steps of
charging red-hot coke 9 from above the prechamber,
exchanging heat with the sensible heat of the red-hot
coke by using an inert gas as a medium in the quenching
chamber, supplying air (hereinafter referred to as the

"SF air 25") to the high-temperature gas 22 discharged from the quenching tower 1 before the gas reaches the waste-heat boiler and recovering heat in the form of steam in the waste-heat boiler 7, the method is characterized by
adjusting the quantity of the SF air so that the concentration of carbon monoxide or hydrogen in the gas circulating in the waste-heat boiler 7 or the heat release of the circulating gas due to the presence of the gases is maintained constant and the concentration of oxygen is kept below a certain level.
(13) The method described in (12) above, in which
the quantity of the SF air 25 is adjusted by setting a
target value for the concentration of carbon monoxide in
the gas circulating in the waste-heat boiler and an upper
limit, a lower limit and a target value for the
concentration of oxygen in the gas, adjusting the
quantity of the SF air so that the carbon monoxide
concentration becomes equal to the target value,
adjustment of the quantity of the SF air based on the
carbon monoxide concentration is suspended to make the
oxygen concentration equal to the target value when the
oxygen concentration exceeds the upper limit therefor,
and adjustment of the quantity of the SF air based on the
carbon monoxide concentration is resumed when the oxygen
concentration falls below the target value or lower limit
therefor or when the oxygen concentration falls below the
target value or lower limit therefor and the carbon
monoxide concentration exceeds the target value therefor.
(14) The method described in (12) above, in which
the quantity of the SF air 25 is adjusted by setting a
target value for the concentration of hydrogen in the gas
circulating in the waste-heat boiler and an upper limit,
a lower limit and a target value for the concentration of oxygen in the gas, adjusting the quantity of the SF air so that the hydrogen concentration becomes equal to the target value, adjustment of the quantity of the SF air

based on the hydrogen concentration is suspended to make the oxygen concentration equal to the target value when the oxygen concentration exceeds the upper limit therefor, and adjustment of the quantity of the SF air based on the hydrogen concentration is resumed when the oxygen concentration falls below the target value or lower limit therefor or when the oxygen concentration falls below the target value or lower limit therefor and the hydrogen concentration exceeds the target value therefor.
(15) The method described in (12) above, in which
the quantity of the SF air 25 is adjusted by determining
the heat release of the circulating gas by adding the
product of the concentration and heat release of hydrogen
in the circulating gas in the waste-heat boiler to the
product of the concentration and heat release of carbon
monoxide in the circulating gas, setting a target value
for the heat release of the circulating gas, setting an
upper limit, a lower limit and a target value for the
concentration of oxygen in the circulating gas, and
adjusting the quantity of the SF oxygen so that the heat
release of the circulating gas becomes equal to the
target value therefor, adjustment of the quantity of the
SF air based on the heat release of the circulating gas
is suspended to make the oxygen concentration equal to
the target value when the oxygen concentration exceeds
the upper limit therefor, and adjustment of the quantity
of the SF air based on the heat release of the
circulating gas is resumed when the oxygen concentration
falls below the target value or lower limit therefor or
when the oxygen concentration falls below the target
value or lower limit therefor and the heat release of the
circulating gas exceeds the target value therefor.
(16) The method described in any of (12) to (15)
above, in which the quantity of the SF air 25 is adjusted
by detecting variation in the quantity of the coke 10
discharged from the quenching tower 1 so that variation

in the concentration of carbon monoxide or hydrogen in the circulating gas in the waste-heat boiler, or the heat release of the circulating gas and the concentration of oxygen due to the detected variation in the quantity of the coke discharged is prevented,
(17) The method described in any of (12) to (16)
above, in which the quantity of the SF air 25 is adjusted
by detecting variation in the quantity of the PC air 24
and/or the PC water-steam 26 so that variation in the
concentration of carbon monoxide or hydrogen in the
circulating gas in the waste-heat boiler, or the heat
release of the circulating gas and the concentration of
oxygen due to the detected variation in the quantity of
the PC air 24 and/or the PC water-steam 26.
(18) The method described in any of (12) to (16).
above, in which air (the PC air 24) and/or water or steam
(the PC water'Steam 26) is injected into the prechamber
3, the quantity of the SF air 25 and the PC air 24 and/or
the PC water-steam 26 is adjusted in the adjustment of
the SF air 25 based on the concentration of carbon
monoxide or hydrogen or the heat release of the
circulating gas and the ratio of the decrement of the PC
air 24 and/or the PC water-steam 26 to the increment of
the SF air 25 is determined so that the heat input to the
waste-heat boiler 7 is maintained constant.
(19) The method described in (18) above, in which
the ratio of the adjusted quantity of the PC water-steam
26 to the adjusted quantity of the PC air 24 is
determined so that the temperature in the prechamber is
maintained constant.
(20) A coke dry quenching method that uses a
quenching tower 1 comprising a quenching chamber 2 and a
prechamber 3 on top thereof, comprises the steps of
charging red-hot coke 9 from above the prechamber,
injecting air and/or water or steam into the prechamber
3, exchanging heat with the sensible heat of the red-hot
coke by using an inert gas as a medium in the quenching

chamber and recovering the sensible heat of the high-temperature gas discharged from the quenching tower 1 in the form of steam in the waste-heat boiler 7, the method is characterized by
bypassing part of the gas discharged from the waste-heat boiler 7 and supplied to the quenching chamber 2,
merging the bypassed gas (hereinafter referred to as the "bypassed gas 29") with the gas supplied to the waste-heat boiler, and
adjusting the quantity of the bypassed gas 29 so that the quantity of the high-temperature discharge gas 22 from the quenching tower 1 becomes equal to the target value therefor.
(21) The method described in (20) above, in which
the quantity of the bypassed gas is adjusted so that the
pressure of the gas supplied to the waste-heat boiler
measured between the exit end of the quenching tower and
the entry end of the waste-heat boiler, instead of the
quantity of the high-temperature discharge gas 22 from
the quenching tower 1, becomes equal to the target value.
(22) The method described in (2) or (19) above, in
which the temperature in the prechamber is measured and,
when the measured temperature in the prechamber differs
from the target value therefor, the ratio of the adjusted
quantity of the PC water-steam 26 to the PC air 24 is
corrected so that the temperature in the prechamber
becomes equal to the target value therefor.
(23) A coke dry quencher comprising a quenching
tower 1 that comprises a quenching chamber 2 and a
prechamber 3 disposed on top thereof from above which
red-hot coke 9 is charged, an injector (14, 16) that
injects air and/or water or steam into the prechamber,
and a waste-heat boiler 7 that exchanges the sensible
heat of the red-hot coke in the quenching chamber by
using an inert gas as a heat-exchange medium and recovers
the sensible heat of the high-temperature gas discharged

from the quenching tower in the form of steam, the quencher is characterized by
comprising an SF air injector 15 that
supplies air (SF air 25) to the high-temperature gas 22 discharged from the quenching tower 2 and a bypass tube 19 that branches part of the gas discharged from the waste-heat boiler and supplied to the quenching chamber as an inert gas and merges the bypassed gas (the bypass gas 29) with the gas supplied to the waste-heat boiler, and
disposing the merging point of the bypass tube 19 upstream (opposite to the boiler) of the SF air injector in the path of the high-temperature gas discharged from the quenching tower 1 and led to the waste-heat boiler 7.
The inventions described in (1) to (6) and (11)
above relate to the feedback control to maintain constant
the quantity of steam recovered from the waste-heat
boiler. '
The inventions described in (7) to (10) above relate to the feedforward control to maintain constant the quantity of steam recovered from the waste-heat boiler in the presence of disturbances.
The inventions described in (12) to (15), (18) and (19) above relate to the feedback control to minimize the contents of combustible components and oxygen in the circulating gas.
The inventions described in (16) and (17) above relate to the feedforward control to minimize the contents* of combustible components and oxygen in the circulating gas in the presence of disturbances.
The inventions described in (20) and (21) above relate to the feedback control to maintain constant the high-temperature gas discharged from the quenching chambe r.
The invention described in (22) above relate to the feedback control to maintain constant the temperature

the prechamber.
The invention described in (23) above relate to the coke dry quenching system to avoid damage due to abnormal local temperature increases of the sloping flue brick.
(II) In the inventions to achieve the sixth object described earlier, water or steam is injected, together with air, into the prechamber. The water-gas reaction that occurs when red-hot coke comes in contact with steam is an endothermic reaction generating hydrogen gas and carbon monoxide. When water is injected, an endothermic reaction due to vaporization of water also occurs, in addition to the endothermic reaction due to water-gas reaction.
Therefore, while air injection into the prechamber heats the inside of the prechamber, injection of water or steam into the prechamber gives rise to an endothermic reaction, with the result that the temperature in the prechamber is maintained at or below a certain level. Specifically, controlling the temperature in the prechamber at or below 1150 °C prevents the melting and gasification of ash in the prechamber and adhesion of clinker to the gas circulation system.
A first feature of the present invention is that it involves an advantageous method and apparatus to inject air and water into the prechamber. A second feature of the present invention is that it involves an advantageous method and apparatus to measure the temperature in the prechamber in controlling the temperature in the prechamber when controlling the temperature at or below a certain level by injecting air with water or steam into the prechamber.
The gist of the present invention to achieve the sixth object ^hereof is as described below:
(24) A coke dry quenching method that uses a quenching tower 1 comprising a quenching chamber 2 and a prechamber 3 on top thereof, comprises the steps of charging red-hot coke 9 from above the prechamber,

injecting air 24 with water 26 into the prechamber from above thereof/ exchanging heat with the sensible heat of the red-hot coke by using an inert gas as a medium in the quenching chamber and recovering heat in the form of steam, the method is characterized by
atomizing the water 26 to be injected into the prechamber to a fine mist and
injecting the mist into the prechamber together with the air 24.
(25) The method described in (24) above, in which
two or more injection ports 45 to inject the air and
water into the prechamber are disposed along the
circumferential direction of the prechamber, with the
angle 9 between the adjoining injection ports disposed
along the circumferential direction of the prechamber
kept within the following range:
0.5 x (360/N) 9(°) S 1.5 x (360/N) where 9 is the angle between adjoining injection ports disposed along the circumferential direction of the prechamber and N is the number of injection ports.
(26) The method described in (24) or (25) above, in
which the injection ports 45 to inject the air and water
into the prechamber are disposed at a level above the
preset upper limit of the coke charge in the prechamber.
(21) The method described in (26) above, in which the injection of the air and water into the prechamber is interrupted or decreased when the top end of the coke charge in the prechamber exceeds the upper limit therefor and the injection of the air and water is resumed or increased when the top end of the coke charge falls below the upper limit or other preset level.
(28) A coke dry quenching method that uses a quenching tower 1 comprising a quenching chamber 2 and a prechamber 3 on top thereof, comprises the steps of charging red-hot coke 9 from above the prechamber, injecting air 24 with water or steam into the prechamber


from above thereof, exchanging heat with the sensible heat of the red-hot coke by using an inert gas as a medium in the quenching chamber and recovering heat in the form of steam, the method is characterized by
measuring the surface temperature of the coke directly below the exit port of the prechamber with a non-contact optical thermometer 18 and
managing or controlling operation by using the measured temperature as the temperature in the prechamber.
(29) The method described in (28) above, in which
air is injected into the prechamber from above thereof
together with water or steam and either or both of the
quantity of water or steam injected and the quantity of
air injected into the prechamber are controlled so that
the temperature in the prechamber becomes lower than the
preset temperature.
(30) A coke dry quencher comprising a quenching
tower 1 that comprises a quenching chamber where the
sensible heat of red-hot coke is exchanged with inert gas
and a prechamber 3 disposed thereabove, a waste-heat
boiler 7 to recover the heat of the inert gas in the form
of steam, and an injector 46 disposed on top of the
prechamber to inject air and water into the prechamber,
the quencher is characterized by
the injector 46 that atomizes water into a fine mist, mixes the fine mist with the air, and injects the mixture into the prechamber,
(31) The quencher described in (30) above, in which
the injector 46 comprises two water spray nozzles 42
disposed one on top of the other in an air injection tube
47 and the water spray nozzles spray water at wide angles
horizontally and at narrow angles vertically.
(32) The quencher described in (30) or (31) above,
in which two or more injection ports 45 constituting the
injector 46 are disposed along the circumferential
direction of the prechamber, with the angle 8 between the

adjoining injection ports disposed along the circumferential direction of the prechatnber kept within the following range:
0.5 x (360/N) (33) The quencher described in (30), (31) or (32)
above, in which the injection ports 45 constituting the
injector 46 are disposed at a level above the preset
upper limit of the coke charge in the prechamber.
(34) A coke dry quencher comprising a quenching
tower 1 that comprises a. quenching chamber where the
sensible heat of red-hot coke is exchanged with inert gas
and a prechamber 3 disposed thereabove, a waste-heat
boiler 7 to recover the heat of the inert gas in the form
of steam, and an injector 46 disposed on top of the
prechamber to inject air and water into the prechamber,
the quencher is characterized by
comprising a non-contact optical
thermometer 18 that is provided to measure the surface temperature of the coke directly below the exit port of the prechamber. [Brief Description of the Drawings]
Fig. 1 is a schematic view of a coke dry quenching method of the present invention.
Fig. 2 comprises block diagrams showing the outline of control according to the present invention. Fig. 2(a) is a block diagram for the invention described in claim 1, (b) is a block diagram for the invention described in claim 2, and (c) is a block diagram for the invention described in claim 3.
Fig, 3 comprises other block diagrams showing the outline of control according to the present invention. Fig. 3(a) is a block diagram for the invention described in claim 6, and (b) is a block diagram for the invention ^described in claim 7.

Fig. 4 comprises still other block diagrams showing the outline of control according to the present invention. Fig. 4(a) is a block diagram for the invention described in claim 12, (b) is a block diagram for the invention described in claim 16, and (c) is a block diagram for the invention described in claim 19.
Fig. 5 is a schematic view of another coke dry quenching method of the present invention.
Fig. 6 is a partial cross-sectional view of the air and water injector of the present invention.
Fig. 7 is a perspective view showing the spraying condition of the water spray nozzle of the present invention.
Fig. 8 shows the condition of the water sprayed according to the present invention. Fig. 8(a) shows the path of the sprayed water in the cross section of the cross section of the prechamber, and (b) shows the area in which water is sprayed at the top surface of red-hot coke.
Fig. 9 shows the area in which water is sprayed at the top surface of red-hot coke by two or more injectors. Fig. 9(a) shows a case in which two injectors are provided, and (b) shows a case in which three injectors are provided. [The Most Preferred Embodiment]
(I) The embodiment for practicing the present invention to achieve the first to fifth objects described earlier is described by reference to Fig. 1.
The quenching tower 1 to quench red-hot coke has a vertically long profile and comprises a prechamber 3 and a quenching chamber 2 that are disposed one on top of the other. A sloping flue 4 formed along the inner wall of the prechamber 3 and quenching chamber 2 divides the gas flow therein.
The red-hot coke 9 having a temperature of approximately 980 °C is charged from above the prechamber 3, gradually moves downward, and quenched in the

quenching chamber 2 by the inert gas 27 blown in through the injection tube 11 disposed in the lower part thereof. The temperature of the coke 10 discharged from the lower part of the quenching chamber is approximately 200 °C.
The inert gas 27 injected into the quenching chamber exchanges heat with the red-hot coke while ascending through the quenching chamber, becomes hotter, and flows out to a ring duct 5 through the sloping flue 4 in the upper part of the quenching chamber. Flowing further from the ring duct 5 to a waste-heat boiler 7 via a primary dust catcher 6, the inert gas is injected into the quenching chamber 2 again via a circulating blower 8 after the temperature thereof has fallen to approximately 180 °C as a result of heat exchange in the waste-heat boiler 7.
In the present invention, air is injected into the prechamber as required. The air injected into the prechamber is hereinafter sometimes referred to as the "PC air 24". The oxygen in the injected air reacts with part of the residual volatile substances, coke fines and coke lumps. The reaction is mainly an endothermic reaction generating carbon monoxide. The injected air, product gas and coke descend in the prechamber while becoming hotter and becomes hottest in the lower part of the prechamber.
The injected air and product gas mix with the inert gas ascending from below in the lower part of the prechamber and flow out to the ring duct 5 via the sloping flue 4.
In the present invention, air is injected, as required, into the prechamber together with water or steam. The water or steam injected into the prechamber is hereinafter sometimes referred to as the "PC water-steam 26",
The injected water absorbs heat when it evaporates to steam and the steam absorbs heat when it comes in contact with red-hot coke and generates hydrogen gas and

carbon monoxide via the water-gas reaction. Therefore, injection of water or steam lowers the temperature of the gas and coke in the prechamber, and thus the temperature of the gas and coke in the prechamber can be controlled by controlling the quantity of the water or steam injected.
The hydrogen gas and carbon monoxide produced by the water-gas reaction descend in the prechamber, mix with the ascending inert gas in the lower part of the prechamber, and flow out to the ring duct 5 via the sloping flue 4.
In the present invention, air 25 is injected, as required, into the ring duct 5 or a gas discharge tube 12 near the sloping flue 4 (SF). The injected gas is hereinafter sometimes referred to as the "SF air 25".
The carbon monoxide produced by the reaction between the PC air 24 and red-hot coke 9 and the carbon monoxide and hydrogen produced by the reaction between the PC water'Steam 26 and red-hot coke 9 burn when they come into contact with the SF air 25 after having flowed out through the ring duct 5 and release heat after changing into carbon dioxide and water.
Steam energy recovery based on the injection of the PC air can be maximized by injecting as much of the SF air 25 as is appropriate for the quantity of the PC air 24 injected and necessary and sufficient for burning the carbon monoxide and other combustible gases produced by the injection of the PC air 24. Also, steam energy recovery based on the injection of the PC water-steam can be maximized by injecting as much of the SF air 25 as is appropriate for the quantity of the PC water-steam 26 injected and necessary and sufficient for burning the combustible gases produced by the water-gas reaction between the PC water-steam 26 and coke 9.
If more oxygen than is required for burning the combustible gases contained in the discharge gas 22 is supplied as the SF air 25, excess oxygen remains in the

circulating gas 37 and is contained in the injected gas
21 and blown into the quenching chamber 2. Therefore, it
is preferable to supply only as much quantity of the SF
air 25 as is required for burning the combustible gases
contained in the discharge gas 22.
In the present invention, part of the gas discharged from the waste-heat boiler 7 and supplied to the quenching chamber via an inert gas injection tube 11 is bypassed, as required, to a bypass tube 19. The bypassed gas (hereinafter referred to as the "bypass gas 29") is merged with the discharge gas 22 in a gas discharge tube
22 and becomes the gas 23 that is supplied to the waste-
heat boiler 23.
In order to maximize the recovery of sensible heat from the red-hot coke in the quenching chamber 2, it is preferable to inject as much gas 21 as possible into the quenching chamber 2. However, there is an upper limit for the flow rate of the gas 22 discharged from the quenching tower 1. Therefore, it is preferable to control the quantity of the gas 21 injected into the quenching chamber 2 so that the quantity of the gas 22 discharged from the quenching tower 1 is maintained in the vicinity of the upper limit therefor.
It is sometimes desirable to increase the supply of the gas 23 to the waste-heat boiler to greater than the required quantity of the injected gas 21 in order to prevent an excessive increase of the temperature of the gas 23 supplied to the waste-heat boiler or for other purposes. On such occasions, the quantity of the gas 23 supplied to the waste-heat boiler can be increased while maintaining the quantity of the injected gas 21 in the vicinity of the upper limit for the quantity of the gas discharged from the quenching tower 1 by bypassing part of the circulating gas 37 to the bypass tube 19 and merging the bypassed gas with the discharged gas 22.
The inventions described in (1) to (6) and (11) above relate to the feedback control to maintain constant


the quantity of steam recovered from the waste-heat boiler. The inventions described in (7) to (10) above relate to the feedforward control to maintain constant the quantity of steam recovered from the waste-heat boiler in the presence of disturbances. In the inventions described in (1) to (11) above, either the PC air alone or both of the PC air and PC water-steam are injected from the prechamber.
If the quantity of the PC air 24 injected is increased, the rate of reaction with the red-hot coke in the prechamber increases which, in turn, increases the quantity of steam recovered. If, conversely, the quantity of the PC air 24 injected is decreased, the quantity of steam recovered decreases. The relationship between the variation in the quantity of the PC air and that in the quantity of the recovered steam depends primarily on the quantity of heat generated by carbon monoxide through the reaction between the oxygen in the PC air and coke. The heat generated by the combustion of the volatile substances contained in the red-hot coke is also involved.
The relationship between the variation in the quantity of the PC air and that in the quantity of the recovered steam for each coke dry quenching system can be determined accurately, based on actual operation data. The relationship between the variation in the injected quantity of the PC water-steam and that in the quantity of the recovered steam can also be determined accurately, based on actual operation data. When the quantity of steam recovered from the waste-heat boiler is maintained constant by feedback control, the heat input to the waste-heat boiler is usually chosen as the controlled variable.
The invention described in (1) is based on the knowledge described above and maintains constant the quantity of steam generated by the waste-heat boiler by controlling the quantity of the PC air 24 when the PC

water'Steam is not injected or the quantity of the PC air 24 and that of the PC water-steam when the PC water*steam is injected so that the heat input to the waste-heat boiler becomes equal to the target value therefor.
Fig. 2(a) shows a block diagram in which the PC air 24 alone is controlled. Concretely, the heat input to the waste-heat boiler is made equal to the target value therefor by adjusting, when the heat input deviates from the target value therefor, the heat release by varying the quantity of the PC air or that of the PC air and the PC water-steam in accordance with the degree of deviation. More concretely, good control can be achieved by optimizing the individual parameters for the PID control.
If the temperature in the prechamber becomes too high, ashes contained in coke melt and gasify. The gasified ashes agglomerate on being cooled by the inert gas near the exit port of the quenching chamber and adhere to the sloping flue in the upper part of the quenching chamber. When the quantity of the PC air 24 is increased to keep constant the quantity of steam recovered in the invention described in (1), it is preferable to maintain constant the temperature in the prechamber.
The temperature in the prechamber can be lowered by increasing the quantity of the PC water-steam injected. The invention described in (2) above is based on this knowledge. In the control to maintain constant the quantity of steam recovered, the quantity of the PC air and that of the PC water-steam are increased at a fixed ratio.
Fig. 2{b) shows a block diagram. The fixed ratio is determined based on experimental or other data so that the temperature increase in the prechamber caused by the increase in the quantity of the PC air matches with the temperature decrease in the prechamber caused by the increase in the quantity of the PC water-steam. Thus,

the feedback control to maintain constant the quantity of heat input to the waste-heat boiler can be achieved while the temperature in the prechamber is maintained constant.
When the PC air 24 or the PC water-steam 26 is injected into the prechamber, the SF air 25 is usually injected to burn the combustible gases generated by the PC air 24 or the PC water*steam 26. If the quantities of the PC air and PC water*steam are adjusted in the inventions described in (1) and '(2) to control the quantity of heat input to the waste-heat boiler 7r the quantity of the combustible gases in the gas 22 discharged from the quenching tower also varies.
If the combustible gases increase, sufficient energy cannot be recovered because the increased gases are sent unburnt to the waste-heat boiler. If the combustible gases decrease, the oxygen from the SF air 25 becomes excessive. Then, the gas containing oxygen is supplied to the waste-gas boiler, and eventually the gas 21 containing oxygen is supplied to the quenching chamber.
In the invention described in (3) above, the ratio of the controlled quantity of the PC air and/or the PC water-steam to the controlled quantity of the SF air is determined so that the concentration of the combustible gases and oxygen in the gas supplied to the waste-heat boiler is maintained constant.
Fig. 2(c) shows a block diagram for this case. The carbon monoxide in the waste gas increases as the quantity of the PC air 24 increases. The quantity of the SF air 25 required for changing the increased carbon monoxide to carbon dioxide by combustion is substantially
f
equal to the quantity of the increased PC air 24.
To be precise, the ratio of the controlled quantity of the SF air to the controlled quantity of the PC air can be determined based on experimental data so that the combustible gases and oxygen in the circulating gas neither increase nor decrease. The same can be done for the ratio of the controlled quantity of the SF air 25 to


the controlled quantity of the PC water-steam 26. In the invention described in (3) above, the quantity of the SF air 25 increases or decreases with an increase or a decrease in the quantity of the PC air 24 and/or the PC water-steam 26. As the quantity of gas burnt in the gas discharge tube 12 also changes with an increase or a decrease in the quantity of the SF air 25, the quantity of heat input into the waste-heat boiler also increases or decreases.
Therefore, in the feedback control implemented when the heat input to the waste-heat boiler diverges from the target value therefor, the amount of adjustment of the PC air 25 along with the PC air 24 or the PC air 24 and the PC water-steam 26 to make constant the heat input to the waste-heat boiler is smaller than that of the PC air, etc. in the inventions described in (1) and (2) above. If the quantity of the PC water'steam 26 alone is increased in the invention described in (1), the quantity of heat input into the waste-heat boiler decreases. If the quantity of the PC water-steam 26 is increased along with that of the SF air 25 in the invention described in (3), the quantity of heat input into the waste-heat boiler increases. Therefore, control parameters must be determined by considering the above factors. Accordingly, the parameters used in the PID control are naturally different from those used in the invention described in (1) above.
Simultaneous implementation of the inventions described in (1), (2) and (3) above permits carrying out a feedback control to maintain constant the temperature in the prechamber and the heat input to the waste-heat boiler without increasing the quantities of combustible gases and oxygen contained in the gas supplied to the waste-heat boiler.
In the feedback control to maintain constant the steam recovery from the waste-heat boiler 7, control to maintain constant the quantity of heat input thereto is


usually practiced by choosing the quantity of heat input to the waste-heat boiler 7 as the controlled variable. However, even if control is done to make constant the heat input to the waste-heat boiler, the quantity of heat generated by the waste-heat boiler 7 sometimes varies, instead of becoming constant.
The inventors learned through studies that the first reason for the variation in the quantity of steam generation is that the unburnt combustible gases and oxygen remain in the gas 23 supplied to the boiler and the unburnt gases burn therein and generate steam having an energy greater than the quantity of heat input to the boiler. Oxygen will remain when the air introduced as the SF air 25 has not completed combustion before reaching the entry end of the boiler and when outside air comes into the boiler.
The invention described in (4) above is based on the above knowledge and makes it possible to maintain constant steam generation by controlling fluctuation by adjusting so that the quantity of steam generation by the waste-heat boiler, instead of the quantity of heat input thereto, becomes equal to the target value therefor. The actual quantity of steam generation can be determined by providing an orifice flowmeter in the steam main. The actual quantity of steam can also be estimated from the quantity of pure water supplied to the waste-heat boiler.
In the invention described in (5) above, adjustment is made so that the gas temperature at the entry end of the waste-heat boiler, instead of the quantity of heat input thereto, becomes equal to the target value therefor. Determining the quantity of heat input to the boiler requires the temperature, quantity and specific heat of the gas at the entry end of the boiler, involves complex measurement and lowers accuracy.
By comparison, the gas temperature control at the entry end of the boiler according to the invention described in (5) above requires nothing more than the

measurement of temperature. While the quantity and specific heat of the gas at the entry end of the boiler do not change greatly in short time periods,, control to maintain constant temperature permits acquiring constant heat input in short periods of time.
The feedback control based on actual steam generation, as described in (4) above, is difficult when the boiler has a large heat capacity because a large time lag occurs between the quantity of heat input to the boiler and the quantity of heat generated. Meanwhile, the divergence between the quantities of heat input and heat generated fluctuates in very long cycles.
It is therefore preferable for the short cycle feedback control to maintain constant the quantity of steam generation to use the heat input to the waste-heat boiler as the controlled variable, determine the long-cycle relationship between the quantities of steam generation and boiler heat input, derive the heat input from the relationship that makes the quantity of steam generation equal to the target value therefor, and correct the target value for the heat input to the waste-heat boiler or the gas temperature at the entry end of the waste-heat boiler used in the short-cycle feedback control.
The invention described in (6) above is based on this concept and has a feature in that the target value for the quantity of heat input to the waste-heat boiler or the gas temperature at the entry end of the waste-heat boiler is corrected so that the quantity of heat generated by the waste-heat boiler becomes equal to the target value therefor. Fig. 3(a) shows a block diagram for this case.
The invention described in (7) above implements a feedforward control to maintain constant the quantity of steam generation by detecting fluctuations in the quantity of coke 10 discharged from the quenching tower 1 and picking up the detected fluctuations in the quantity

of coke discharge as a disturbance. When the quantity of coke discharged from the quenching tower 1 increases, the quantity of the sensible heat of coke recovered also increases. The increase in the quantity of the sensible heat of coke recovered accompanying the increase in the quantity of coke discharge can be approximately estimated by thermal calculation and accurately determined based on experiments.
Meanwhile, one or more of the quantities of the PC air 24, PC water-steam 26 and SF air 25 can be controlled to cancel the increase in the quantity of the sensible heat of coke recovered. The controlled variable can be accurately determined by thermal calculation and based on experiments so that the quantity of heat supplied to the boiler is maintained constant.
Fig. 3{b) shows a block diagram for the case in which the PC air is chosen as the controlled variable. This figure also shows as block diagram for the feedback control.
The invention described in (8) above implements a feedforward control to maintain constant the quantity of steam generation, as in the invention described in (7), by using the quantity of the circulating gas as a disturbance. When the circulating gas is not bypassed but supplied direct to the "quenching chamber, the balance left after deducting the quantity of the liberated gas from the quantity of the circulating gas and that of the liberated gas is used as the quantity of the gas injected into the quenching chamber. If the quantity of the gas injected to the quenching chamber fluctuates, the heat exchange efficiency in the quenching chamber changes/ as a result of which, the quantity of the sensible heat the cooling gas recovers from the red-hot coke changes.
One or more of the quantities of the PC air 24, PC water-steam 26 and SF air 25 is adjusted by predicting the fluctuation in the quantity of sensible heat recovered by thermal calculation and based on

experiments, making up for the fluctuation and implementing a feedforward control so that the quantity of heat input into the waste-heat boiler is maintained constant. The quantity of the gas injected into the quenching chamber, instead of the quantity of the circulating gas, may be detected for use directly.
The invention described in (9) above implements a feedforward control to maintain constant the quantity of heat input to the boiler by using the fluctuation in the quantity of the SF air as a disturbance and adjusting the PC air and PC water*steam.
The invention described in (10) above implements, where the bypass gas 29 is passed through the bypass tube 19, a feedforward control to maintain constant the quantity of steam generation, as with the invention described in (7), by using the fluctuation in the flow rate of the gas injected into the quenching chamber as a disturbance.
When part of the circulating gas is bypassed to the waste-heat boiler, the quantity of the gas injected into the quenching chamber is equal to the balance left after deducting the quantities of the bypassed and liberated gases from the quantity of .the circulating gas. If the quantity of the gas injected to the quenching chamber changes, the heat exchange efficiency in the quenching chamber changes, with the result that the quantity of the sensible heat the cooling gas recovers from the red-hot coke changes. One or more of the quantities of the PC air 24, PC water-steam 26 and SF air 25 is adjusted by predicting the fluctuation in the quantity of sensible heat recovered by thermal calculation and based on experiments, making up for the fluctuation and implementing a feedforward control so that the quantity of heat input into the waste-heat boiler is maintained constant.
Instead of directly determining the quantity of the gas supplied to the quenching chamber, the quantities of

the circulating and bypassed gases may be determined and the difference therebetween may be used as the quantity of the gas injected to the quenching chamber.
The inventions described in {1} to (10) above implement a feedback or a feedforward control to cope with various disturbances and maintain constant the quantity of steam recovered by the waste-heat boiler. The temperature of the gas supplied to the waste-heat boiler may change in this control process.
If the temperature of the gas supplied to the waste-heat boiler exceeds the upper limit of a certain target range, even if the quantity of the heat input to the waste-heat boiler is maintained constant, waste-heat boiler tubes can be thermally damaged. If, on the other hand, the temperature of the gas supplied to the waste-heat boiler falls below the lower limit, the heat recovery efficiency in the waste-heat boiler may drop.
If the quantity of the circulating gas is increased while the quantity of steam generation in the waste-heat boiler, or the quantity of heat input thereto, is maintained constant, the temperature of the gas supplied thereto will naturally drop.
It is therefore preferable to detect the temperature of the gas 23 supplied to the waste-heat boiler and control the quantity of the circulating gas 37 so that the detected temperature of the gas supplied to the waste-heat boiler is kept in the target temperature range. The circulating gas is increased and decreased by opening and closing the circulating gas valve 38 as required.
The inventions described in (12) to (15), (18) and (19) relate to feedback controls to minimize the contents of the combustible components and oxygen in the circulating gas. The inventions described in (16) and (17) relate to feedforward controls to minimize the contents of the combustible components and oxygen in the circulating gas against disturbances.


In the processes that recover all of the sensible heat from red-hot coke in the waste-heat boiler and liberate excess circulating gas to the atmosphere, it is preferable to minimize the combustible components in the circulating gas as described above.
When part of the circulating gas is recovered, instead of being liberated to the atmosphere, the control of the combustible components in the circulating gas according to the present invention assures recovering gases having stable calorific values by setting the target values .for the concentrations of carbon monoxide and hydrogen in the circulating gas and the calorific value of the circulating gas as the properties of the gas to be recovered.
The invention described in (12) above controls so that the concentration of carbon monoxide or hydrogen in the circulating gas 37 in the waste-heat boiler or the quantity of heat generated thereby is maintained constant and the concentration of oxygen therein is maintained below as certain level by controlling the quantity of the SF air 25 supplied to the high-temperature gas 22 discharged from the quenching tower before the gas 22 reaches the waste-heat boiler 7.
Fig. 4(a) shows a block diagram for this case. Though injection of the PC air 24 and the PC water-steam is not essential here, the SF air 25 is usually supplied with'a view to burning the carbon monoxide resulting from the injection of the PC air 24. Therefore, at least the PC air 24 is often injected simultaneously.
It is preferable to determine the composition of the gas 37 circulating in the waste-heat boiler 7 by sampling the gas coming out of the waste-heat boiler 7, because the reaction between the unburnt gas and oxygen sometimes continue at or downstream of the entry end of the waste-heat boiler. If unburnt combustible gas is detected in the circulating gas, the supply of the SF air 25 is increased to a level that is necessary and sufficient to

burn such unburnt combustible gas. If oxygen is detected in the circulating gas 37, as much of the SF air 25 as is equivalent to the quantity of the detected oxygen is decreased.
If the combustible components and oxygen coexist in the circulating gas, it must be decided which of the combustible gas and oxygen is used in the control. In the process in which the combustible components consist primarily of carbon monoxide, control can be implemented by focusing attention on only carbon monoxide.
The invention described in (13) above implements control by setting the target value for the concentration of carbon monoxide in the gas circulating in the waste-heat boiler and the upper limit and target value for the concentration of oxygen therein.
Usually, the quantity of the SF air is controlled so that the concentration of carbon monoxide becomes equal to the said target value. If the concentration of oxygen exceeds the upper limit therefor, the quantity of the SF oxygen is controlled to said target value by interrupting the control of the quantity of the SF air based on the concentration of carbon monoxide. If the concentration of oxygen falls below the target value or lower limit therefor, or the concentration of oxygen falls below the target value or lower limit therefor and the concentration of carbon monoxide exceeds the target value therefor, the control of the quantity of the SF air based on the concentration of carbon monoxide is resumed.
These controls permit always and stably maintaining the concentrations of carbon monoxide and oxygen in the circulating gas below certain low levels.
In the process in which the combustible components consist primarily of hydrogen, it is preferable to implement the control described in (14) above by focusing attention on only hydrogen.
In the processes in which carbon monoxide and hydrogen coexist as combustible gases, attention is

focused on the quantities of heat generated by the individual combustible gases. Then, as in the invention described in (15) above, the sura of the product of the concentration of carbon monoxide in the gas multiplied by the quantity of heat generated by carbon monoxide and the product of the concentration of hydrogen in the gas multiplied by the quantity of heat generated by hydrogen is used as the quantity of heat generated by the circulating gas and the target value therefor is set.
Meanwhile/ the upper limit and target value for the concentration of oxygen in the gas are set. Usually, then, the quantity of the SF air is controlled so that the quantity of heat generated by the circulating gas becomes equal to the target value therefor. If the concentration of oxygen exceeds the upper limit therefor, the quantity of the SF oxygen is controlled to the target value by interrupting the control of the quantity of the SF air based on the quantity of heat generated by the circulating gas. If the concentration of oxygen falls below the target value or lower limit therefor, or the concentration of oxygen falls below the target value or lower limit therefor and the concentration of carbon monoxide exceeds the target value therefor, the control of the quantity of the SF air based on the quantity of heat generated by the circulating gas is resumed.
These controls permit always maintaining the concentrations of carbon monoxide, hydrogen and oxygen in the circulating gas and the quantity of heat generated by the circulating gas below certain safe levels. It is preferable to derive from the actual operation and set the target values for the concentration of carbon monoxide or hydrogen and the quantity of heat generated by the circulating gas at the minimum points greater than zero and at which the concentration of oxygen does not exceed the upper limit therefor.
The invention described in (16) above implements a feedforward control to prevent the fluctuation of the

concentration of carbon monoxide or hydrogen and the concentration of oxygen in the gas circulating in the waste-heat boiler by detecting the fluctuation in the quantity of coke 10 discharged from the quenching tower and using the detected fluctuation as a disturbance.
if the quantity of coke discharged from the quenching tower increases, the quantity of the combustible gases in the circulating gas also increases. The increase in the quantity of the combustible gases accompanying the increase in the coke discharge can be determined by calculation and experiment.
The control can be done without varying the quantities of the combustible components and hydrogen in the circulating gas even when the quantity of coke discharge fluctuates by deriving the increase in the SF air to cancel the increase »in the combustible gases and implementing a feedforward control.
Fig. 4(b) shows a block diagram for this case, along with a diagram for the feedback control.
The invention described in (17) above prevents an increase of the combustible gases and oxygen in the circulating gas by using the fluctuation in the quantity of the PC air 24 as a disturbance and implementing a feedforward control as in the invention described in (16) above. By implementing the invention described in (17) simultaneously with the inventions described in (I) and (9), it is possible to carry out a feedback control to maintain constant the quantity of steam recovery while maintaining constant the concentrations of the combustible gases and oxygen in the circulating gas, as with the invention described in (3) above.
If the quantity of the SF air 25 is increased or decreased in the inventions described in (12) to (15) to prevent an increase in the combustible gases and oxygen in the circulating gas, the quantity of combustion in the gas discharge tube 12 fluctuates to vary the quantity of steam recovered from the waste-heat boiler 7.

In controlling the quantity of said SF air 25 so that the concentrations carbon monoxide, hydrogen and oxygen in the circulating gas and the quantity of heat generated by the circulating gas are maintained below certain levels, the invention described in (18) controls not only the quantity of the SF air 25 but also the quantity of the PC air 24 and/or the PC water-steam 26. The ratio of the increase in the quantity of the SF air 25 to the decrease in the quantity of the PC air 24 and/or the PC water-steam 26 is determined so that the quantity of heat input to the waste-heat boiler 7 is maintained constant.
If the concentration of the carbon monoxide in the circulating gas exceeds the control limit, the increase in the SF airf which is a reaction to burn carbon monoxide and hydrogen, lowers the concentrations of carbon monoxide and hydrogen in the circulating gas. The decrease in the quantity of the PC air and the PC water-steam, which decreases the generation of carbon monoxide in the prechamber, also lowers the concentration of carbon monoxide in the circulating gas.
Meanwhile, an increase in the quantity of the SF sir increases the quantity of steam generation and the decrease in the quantity of the PC water-steam decreases the quantity of steam generation.
It is therefore possible to set the ratio of the increase in the quantity of the SF air to the decrease in the quantity of the PC air so that the quantity of steam recovered remains constant. It is in turn possible to decrease the concentrations of carbon monoxide and hydrogen in the circulating gas without varying the quantity of steam recovered.
If the PC water-steam is decreased while increasing the SF air, the hydrogen in the circulating gas also decreases. Therefore, it is possible to further decrease the concentration of hydrogen in the circulating gas without varying the quantity of steam recovered.

If the concentration of oxygen in the circulating gas is above the control limit, the concentration is lowered by decreasing the SF air. This decrease does not affect the quantity of steam recovered, because the quantity of combustible gas burning in the gas discharge tube does not change. Therefore, the concentration of oxygen in the circulating gas can be lowered by decreasing the SF air 25 alone, without changing the quantity of the PC air 24 and the PC water•steam 26.
In maintaining the quantities of combustible gases and oxygen in the circulating gas, the invention described in (19) above maintains constant the quantity
of steam recovered by the waste-heat boiler and the temperature in the prechamber, as with the invention described in (18).
In controlling the quantity of the SF air so that the concentrations of carbon monoxide, hydrogen and oxygen in the circulating gas and the quantity of heat generated by the circulating gas are maintained below the predetermined quantities, the quantities of the PC air and PC water-steam are controlled along with the quantity of the SF air.
The ratio of the increase in the quantity of the SF air to the decrease in the quantity of the PC air and PC water'Steam is determined so that the quantity of heat input to the waste-heat boiler is maintained constant. The invention described in (18) determines the ratio of the quantity of the PC air adjusted to the quantity of the PC water'Steam adjusted so that the temperature in the prechamber is maintained constant.
An increase in the quantity of the PC air in the prechamber increases the quantity of heat generated and an increase in the PC water-steam decreases the quantity of heat generated. Therefore, the temperature in the prechamber can be maintained constant by determining an appropriate ratio for the increase in the PC air and the increase in the PC water-steam. Fig. 4{c) shows a block

diagram for this case.
The high-temperature gas discharged from the quenching tower is supplied to the waste-heat boiler 7 via the sloping flue 4. If the quantity of the discharged gas exceeds upper limit therefor, coke will float and burst from the sloping flue 4. Then, the sharply increased resistance to the flow of the circulating gas and scattering coke will cause wear and damage boiler tubes. Therefore, it is necessary to control the flow rate of the high-temperature gas below a certain level.
In order to achieve energy saving by always maximizing the recovery of sensible heat from red-hot coke in the quenching chamber 2, it is important to increase the supply of inert gas to the quenching chamber 2 as much as possible. Because there is an upper limit for the quantity of the discharge gas from the quenching tower, it is necessary to constantly control at the upper limit.
The invention described in (20) above provides a bypass tube 19 in the flow route of the circulating gas and controls the quantity of the bypass gas 29 so that the quantity of the discharge gas 22 becomes equal to the target value therefor. By increasing the quantity of the bypass gas 29, the quantity of the gas injected from the inert gas injection tube 11 can be decreased while maintaining constant the quantity of the circulating gas 37, thereby decreasing the quantity of the discharge gas 22.
The invention described in (21) above controls the quantity of the bypass gas so that the pressure of the gas supplied to the boiler determined between the exit end of the quenching chamber and the entry end of the waste-heat boiler, instead of the quantity of the discharge gas, becomes equal to the target value therefor.
In order to determine the quantity of the high-

temperature gas discharged from the quenching tower in the invention described in (20) above, it is necessary to derive the quantity of the gas from the quenching chamber from the quantities of the circulating, liberated and bypass gases and the quantity of the gas from the prechamber on the basis of the quantities of the PC air, PC water-steam and the gas increased by the reaction. Because, however, determination or estimation of these quantities is complicated and demanding, the pressure of the gas supplied to the boiler, which is known to have a certain relationship with the quantity of the high-temperature gas discharged from the quenching tower, is used instead.
The inventions described in (2) and (19) maintain constant the temperature in the prechamber by predetermining the ratio of the control quantity of the PC air to the control quantity of the PC water-steam.
Since, however, various operating conditions of the dry quenching system vary, the actual temperature in the prechamber sometimes does not become equal to the target value therefor even if it is controlled by using the predetermined ratio mentioned above.
The invention described in (22) above controls the temperature in the prechamber to become equal to the target value therefor by measuring the temperature in the prechamber and correcting the ratio of the control quantity of the PC air to the control quantity of the PC water'steam if the measured temperature in the prechamber differs from the target value therefor.
This control always keeps the temperature in the prechamber equal to the target value therefor, even if any variation occurs in the operating parameters of the system.
When the SF air is introduced into the gas discharge tube 12 and the combustible components are burnt, the heat of combustion raises the temperature of the discharge gas 22. Especially when the bypass gas is

passed through the bypass tube 19, the temperature of the discharge gas 22 is high before the gas discharge tube 12 and the bypass tube 19 meet.
If, therefore, the SF air is introduced and the combustible components are burnt in the areas of the ring duct 5 or sloping flue 4 upstream of the merging point with the bypass tube 19, the temperature of the discharge gas becomes so high that the resulting abnormal local temperature rise sometimes"damages the refractory bricks in the sloping flue area.
In the invention described in (23) above, the temperature of the discharge gas does not become so high as to damage the refractory bricks through abnormal local temperature rise, even if the combustible gases are burnt by the SF air 25 because the SF air is introduced after the temperature of the discharge gas 22 has dropped by mixing with the bypass gas 29.
While the inventions described in (1) to (23) individually achieve their effects, it is preferable to combine some of them, because such combination permits integrating the effects of the combined inventions. [Example 1]
The present invention was implemented in the coke dry quenching system shown in Fig, 1. The quenching chamber 2 and prechamber 3 of the dry quenching system had an internal volume of 600 in3 and 300 m3. The red-hot coke 9 having an average temperature of 980 *C was quenched at an average discharge rate of 170 ton/hour. The PC air was injected from above the prechamber into a space 31 between the top surface 30 of the red-hot coke and the prechamber. The PC water-steam 26 to control the temperature in the prechamber was injected after being mixed with the PC air 24 in the piping of the air injector 14.
An apparatus to inject the SF air 25 into the gas discharge tube 12 was provided to raise the temperature of the discharge gas by burning the combustible

components in the discharge gas 22 from the quenching tower 1 and control the composition of the circulating gas 37.
The bypass tube 19 was provided to branch part of the inert gas supplied from the circulating blower 8 to the quenching chamber 2 for merging with the discharge gas. The sampling tube 37 "was disposed at the exit end of the boiler to determine the concentrations of oxygen, carbon monoxide and hydrogen in the circulating gas.
Control systems and apparatus were composed by combining the inventions described in (1) to (3), (6) to (8), (10) to (13), (16), (18) to (20), (22) and (23). The target value for the quantity of steam generated 35 by the waste-heat boiler 7 was set at 130 ton/hour, that for the carbon monoxide concentration in the circulating gas 37 at 0.3 %, the upper limit of the oxygen concentration at 0.3 %, the lower limit and target value therefor at 0.1 %, the target value for the temperature in the prechamber at 1000 °C, the upper and lower limits of the temperature of the gas 23 supplied to the waste-heat boiler at 980 °C and 950 °C, and the target value of the quantity of the discharge gas 22 from the quenching tower 1 at 264000 NmVhour, and continuous control was carried out over long hours.
A steam generation 35 of 130 ton/hour was achieved at average operating conditions with the quantities of the circulating gas at 298000 NmVhour, PC air at 10000 NmVhour, SF air at 30000 NraVhour, bypass gas at 10000 NmVhour, and PC water at 1.5 ton/hour. At the same time, the fluctuation of the steam generation 35 averaged over a period of one hour was controlled within the range of ±1.5 ton/hour.
Even when the preset quantity of discharge was changed from 170 ton/hour to 120 ton/hour, the quantity of steam generation 35 was controlled within the range of plus/minus 1.5 ton/hour of 130 ton/hour.

The average concentration of carbon monoxide in the circulating gas 37 averaged 0.3 % and that of oxygen was kept not higher than 0.1 %. Table 1 shows the results described above together with the results from prior arts. The actual temperature in the prechamber, the actual temperature of the gas 23 supplied to the waste-heat boiler and the actual quantity of the discharge gas 22 were 1000 °C, 965 °C and 264000 NmVhour. As a consequence, there occurred no foreign matter adhesion to the sloping flue, no thermal damage to the waste-heat boiler tubes, and no drop in the heat recovery efficiency in the waste-heat boiler. While an increase in the resistance to the flow of the circulating gas and wear and damage of the waste-heat boiler tubes due to the floating and bursting of coke from the sloping flue were avoided, stable operation was achieved with no abnormal local temperature rise occurring in the refractory bricks of the sloping flue.
Furthermore, the actual temperature of the discharged coke was 180 °C and the quantity of the sensible heat recovered from the red-hot coke was maximized under the stable operating conditions described above.
[Table 1] Table 1 Comparison of Control Effects
(Table Removed)

(II) The mode for practicing the present invention to achieve the sixth object described earlier is described by reference to Figs. 5 to 9.
The quenching tower 1 to quench red-hot coke has a vertically long profile and comprises a prechamber 3 and a quenching chamber 2 that are disposed one on top of the

other, as shown in Fig. 5. A sloping flue 4 formed along the inner wall of the prechamber 3 and quenching chamber 2 divides the gas flow therein.
The red-hot coke 9 having a temperature of approximately 980 °C is charged from above the prechamber 3, gradually moves downward/ and is quenched in the quenching chamber 2 by the inert gas 27 blown in through the injection tube 11 disposed in the lower part thereof. The coke 10 discharged from the lower part of the quenching chamber is approximately 210 °C.
The inert gas 27 injected into the quenching chamber exchanges heat with the red-hot coke while ascending through the quenching chamber, becomes hotter, and flows out to a ring duct 5 through the sloping flue 4 in the upper part of the quenching chamber. Flowing further from the ring duct 5 to a waste-heat boiler 7 via a primary dust catcher 6, the inert gas is injected into the quenching chamber 2 again via a circulating blower 8 after the temperature thereof has fallen to approximately 180 °C as a result of heat exchange in the waste-heat boiler 7.
In the present invention air 24 is injected into the prechamber through the air injector 14 above the prechamber. The air injected into the prechamber is hereinafter sometimes referred to as the "PC air 24". The oxygen in the injected air reacts with part of the residual volatile substances, coke fines and coke lumps. The reaction is mainly an endothermic reaction generating carbon monoxide. The injected air, product gas and coke descend in the prechamber while becoming hotter and become hottest in the lower part of the prechamber.
The injected air and product gas mix with the inert gas ascending from below in the lower part of the prechamber and flow out to the ring duct 5 via the sloping flue 4. The air 25 may be injected from the air injection tube 15 to the ring duct 5 or gas discharge

tube 12. This changes the carbon monoxide generated in the prechamber to carbon dioxide by burning.
In this invention, the water injector 16 injects water 26 into the prechamber from thereabove. The water injector may also inject steam together with the water. While the injected water absorbs heat when it evaporates to steam,.the steam absorbs heat when it comes in contact with the red-hot coke and generates hydrogen gas and carbon monoxide by the water-gas reaction.
Thus, injection of water or steam lowers the temperatures of the gas and coke in the prechamber, and the temperatures of the gas and coke in the prechamber can be controlled by adjusting the quantity of water or steam injected.
The hydrogen gas and carbon monoxide produced by the water-gas reaction descend in the prechamber, mix with the ascending inert gas in the lower part of the prechamber, and flow out to the ring duct 5 via the sloping flue 4. If the air 25 is injected into the ring duct 5 or gas discharge tube 12, the air 25 changes the hydrogen gas and carbon monoxide to water and carbon dioxide by burning. At the same time, the heat of combustion increases the calorific value of the gas 23 supplied to the waste-heat boiler.
If water or steam is injected into the prechamber, the quantity of heat of the gas 23 at the entry end of the waste-heat boiler increases. Therefore, it is also possible to decrease the quantity of air injection to the prechamber while securing the quantity of heat required by the waste-heat boiler.
In other words, it is possible to simultaneously control the highest temperature in the prechamber and the quantity and temperature of the gas 23 supplied to the waste-heat boiler to the optimum levels by controlling either or both of the quantity of air injection to the prechamber and the quantity of water or steam injection thereto.

The inert gas acquires high calorific value by quenching the red-hot coke. When a sufficient quantity of heat to supply to the waste-heat boiler can be obtained, it is possible to lower the temperature in the prechamber by decreasing the quantity of the air 24 injected to the prechamber, without supplying water or steam.
While the ash in coke dust used to be considered to melt at temperatures above 1400 °C, it was found through many tests that the ash in coke dust melts at
approximately 1200 °C. More specifically, there is a tendency for the melting temperature to lower particularly when coke dust contains many components. It was found that 1150 °C is a key operational standard when temperature variation in the cross section of the prechamber having a radius of approximately 10 m. Furthermore, it is effective to control at low temperatures for the maintenance of safe and stable operation over long periods of time.
The inventions described in (24) and (30) are the coke dry-quenching method and system that atomizes the water 26 to be injected into the prechamber together with the air 24 and injects a mixture of the atomized water and air into the prechamber. Steam may also be injected into the prechamber together with the air and water.
The water 24 injected into the prechamber must be uniformly sprayed over the surface of the top layer 30 of the red-hot coke charged in the prechamber. Nonuniform spraying results in excessive cooling of the red-hot coke in the area where much water is sprayed and insufficient cooling in the area where little or no water is sprayed. If, however, water is sprayed to the red-hot coke near the wall brick of the prechamber with a view to assuring uniform cooling, water splashing on the brick causes damage thereto.
Atomizing the water sprayed into the prechamber, as

done by the invention/ prevents the water sprayed on to the red-hot coke from splashing on the brick/ and mixed injection of the atomized water with air into the prechamber permits uniform extensive spraying of the atomized water over the surface of the red-hot coke in the prechamber.
However, the atomized water does not necessarily mean a mist containing no water drops at all. Atomized water of the type obtained with common flat spray nozzles containing small water drops can serve the purpose.
In the invention described in (31) above, the injector 46 that injects a mixture of atomized water and air into the prechamber has two water spray nozzles (42a, 42b) that are disposed, one on top of the other, in the air injection tube 47, as shown in Fig. 6. The water spray nozzles spray water at wide angles horizontally and at narrow angles vertically, as shown in Fig. 7. In Fig, 7, reference numerals 43 and 44 respectively designate the path of the sprayed water and the area of spraying.
Of the two water spray nozzles, the upper nozzle 42a sprays water mainly on the surface of the red-hot coke far away from the injector in the prechamber by adjusting the spraying rate and angle so that the water reaches far. The lower nozzle 42b sprays water mainly on the surface of the red-hot coke close to the injector in the prechamber by adjusting the spraying rate and angle so that the water covers a near by range.
Provision of the two spray nozzles, one atop the other, permits spraying water uniformly from the closer area to the farther area in the prechamber as shown in Fig. 8(a).
In the coke layers in the prechamber, more gas flows near the wall of the prechamber than in the midsectlon thereof, because the distance to the sloping flue is shorter and the resistance to the gas flow in the coke layers is smaller.
Because of this, more gas flows toward the wall of

the prechamber in the upper space 31 thereof, and, accordingly/ the atomized water injected is further dispersed in the direction of circumference, thus covering the whole top surface 30 of the coke layers.
Two or more injectors of the invention may be disposed at different points along the circumference of the prechamber. In this case, one injector is required to cover the area from near the injector to the center of the prechamber, not the whole area over the diameter thereof.
AS the water spray nozzles spray water at wide angles horizontally, water is sprayed over the surface of the red-hot coke covering the whole area of the prechamber expanding on both sides thereof, as shown in Fig. 8(b). Meanwhile, the water spray nozzles spray water substantially horizontally.
Even if the vertical spraying angle is narrow, the water spray nozzles sufficiently cover half the area of the prechamber.
Being disposed in the air injection tube 47, the water spray nozzles 42 send the atomized water carried by the high-speed air stream to the remote side of the prechamber away from the injector 46.
The inventions described in (25) and (32) above have two or more injection ports 45 to inject the air and water into the prechamber 3 disposed along the circumferential direction of the prechamber, with the angle 8 between the adjoining injection ports disposed along the circumferential direction of the prechamber kept within the following range:
0.5 x (360/N) S 0(°) £ 1.5 x (360/N)
where 0 is the angle between adjoining injection ports disposed along the circumferential direction of the prechamber and N is the number of injection ports. For example, 90° £ 9 ^ 270° when there are two injection ports and 60°
If 9 is within the angle ranges, the individual injection ports 45 uniformly spray water over the surface of the top layer 30 of the red-hot coke in the prechamber without overlapping.
Figs. 9 (a) and 9{b) respectively show the spraying range 44 in a case in which the number of injection ports N is 2 and the angle 0 is 180° and a case in which N is 3 and the angle 9 is 120*.
It is preferable to inject the air and water or steam into the space 31 between the top 30 or surface of the red-hot coke layers and the prechamber. If the air and water or steam is injected into the red-hot coke layers 32, the reaction proceeds only in the coke near the point of gas injection. The resulting nonuniform gas distribution causes variations in temperature distribution and reactivity across the cross section of the prechamber.
In addition, the air and water or steam splashing back from the coke layers hit a localized portion of the brick near the injection port and damage the brick through localized cooling.
While the quantity of the coke 10 discharged from the quenching chamber does not vary much with time, the charge of the red-hot coke 9 into the prechamber is made in a large quantity at a time and interrupted subsequently. Therefore, the surface position of the top 30 of the red-hot coke layers in the prechamber changes from time to time.
It is preferable to set the port 45 to inject the air and water from above the prechamber above the predetermined upper limit of the coke charge therein as in the inventions described in (26) and (33) above. This keeps the air and water injection port 45 always above the red-hot coke layers, even if the coke charge in the prechamber chamber changes with time.
If the charging rate of the red-hot coke temporarily

exceeds the discharge rate of the coke from the quenching chamber/ the top end of the red-hot coke in the prechamber sometimes exceeds the predetermined upper limit of the coke charge.
On such occasions,, it is preferable to interrupt or decrease the injection of the air and water into the prechamber when the top end of the red-hot coke in the prechamber sometimes exceeds the predetermined upper limit of the coke charge and resume or increase the injection of the air and water when the top end of the coke falls below the upper limit or an otherwise predetermined level as in the invention described in (27) above.
This control avoids nonuniform dispersion of gas that will result if the air and water are injected directly into the red-hot coke layers. The top end of the coke in the prechamber can be detected by the arithmetic method using the coke charge and discharge based on the calibration of the prechamber level gauge.
It is necessary to measure the temperature in the prechamber for controlling the temperature below a certain level in injecting air with water or steam. The measured temperature in the prechamber is sent to the injection control unit 17 that then controls the quantity of the water or steam 16 or the air 24 so that the temperature in the prechamber becomes equal to the target temperature.
The temperature in the prechamber has conventionally been measured by measuring the temperature of the atmosphere or coke near the inner side of the brick with a thermometer passed through the wall of the prechamber from outside thereof, measuring the temperature .of the inner brick or atmosphere with a thermometer inserted into the inner brick, measuring the temperature of the brick near the lower part of the prechamber with a thermocouple thermometer.
Being passed through the brick or the lower part of

the prechamber, the thermocouple or other types of thermometers used in the measuring methods have short lives and thus have to be replaced every time deterioration occurs.
The ring duct 5 to discharge the hot gas that has recovered the sensible heat is provided near the sloping flue 4 in the middle of the quenching tower. The red-hot coke can be directly observed from the side of the sloping flue through the opening in the ring duct 5.
The^inventors discovered that the temperature in the prechamber can be maintained constant with sufficient accuracy by using the temperature of the red-hot coke directly below the prechamfaer observed through the opening of the ring duct 5 with a non-contact optical thermometer 18 as the temperature in the prechamber.
The inventions described in (28), (29) and (34) were made based on the above finding. More specifically, the non-contact optical thermometer 18 to measure the surface temperature of the coke directly below the prechamber is disposed as described in (34) and the temperature measured by said thermometer is used for the maintenance or control of the prechamber as described in (28),
Furthermore, either or both of the quantity of the water or steam and the quantity of the air injected into the prechamber are controlled so that the temperature in the prechamber becomes equal to or lower than the predetermined temperature by injecting air and water or steam from above the prechamber by using the surface temperature of the coke directly below the prechamber with the non-contact optical thermometer 18, as described in (29).
Since the non-contact optical thermometers are much more durable than the conventionally used thermocouple thermometers, they therefore require replacement much less often. In cases of failure, furthermore, the optical thermometers 18 provided in the space near the sloping flue 4 require much less inspection and repair

work than thermocouple thermometers passed through the brick. The non-contact optical thermocouples 18 include radiation pyrometers and two-color pyrometers.
The presence of the air 24 and water or steam 26 injected into the prechamber increases the quantity of the circulating gas 37 flowing between the quenching tower 1 and waste-heat boiler 7. Therefore, it is necessary to r«lease part of the circulating gas as the liberated gas 33 so that the quantity of the circulating gas is maintained constant.
If the circulating gas contains such unburnt gases as carbon monoxide and hydrogen, it is difficult to effectively recover the energy possessed by such unburnt gases. Therefore, it is preferable to ensure that the circulating gas does not contain the unburnt gases at least after having passed the waste-heat boiler by converting the unburnt gases contained in the circulating gas to heat energy by burning with the air supplied.
It is preferable to inject the air 25 from the air injector 14 into the gas recovered from the quenching tower 1 and flowing to the waste-heat boiler 1, as shown in Fig. 5. The air 25 injected into the circulating gas burns the carbon monoxide and hydrogen generated by the reaction between the air, water and steam injected into the precharaber with the red-hot coke. Then, the waste-heat coiler 7 effectively recovers energy from the heat generated when the carbon monoxide and hydrogen become carbon dioxide and water, [Example 2]
The present Invention was implemented in the coke dry quenching system shown in Fig. 1. The quenching chamber 2 and prechamber 3 of the dry quenching system had an internal volume of 600 m3 and 300 m3. The red-hot coke 9 having an average temperature of 980 °C was quenched at an average discharge rate of 170 ton/hour. Two injectors 46 of the type shown in Fig. 6 were provided in the prechamber to simultaneously inject air

and water into the prechamber. The two injectors were disposed at circumferential intervals of 9 = 180°. Two radiation pyrometers were provided at two points near the sloping flue to measure the temperature in the prechamber. The temperature of the red-hot coke observed through the ring duct was measured non-contact, and the mean temperature derived from the measurements obtained at the two points was used as the temperature in the prechamber. The two radiation pyrometers were disposed at points 90° and 270° away along the circumference of the ring duct from the 0° point on the boiler side.
The upper limit and standard value of the coke charge in the prechamber were set at 120 and 110 ton. The injectors 42 were provided 1 m above the surface of the coke charge at the upper limit thereof.
The target for the temperature in the prechamber was set at 1000 °C. In order to maintain constant the quantity of steam generated in the waste-heat boiler 7, the quantity of air injected into the prechamber was varied within the range of -5000 NmVhour and 30000 NmVhour in accordance with the variation in the quantity of coke discharged. In order to maintain the temperature in the prechamber at the target value therefor, the quantity of water injected into the prechamber was varied within the range of 0.5 ton/hour and 2.5 ton/hour.
As a consequence, the actual temperature in the prechamber was controlled within the range of 1000 ±20 °C and no foreign matters adhered to the sloping flue. No prechamber brick damage due to water splashing and local cooling was observed. The non-contact radiation pyrometers worked stably for a long time. [Industrial Applicability]
The present invention permits maintaining constant the quantity of steam generated in the waste-heat boiler of coke dry quenching systems. The present invention also permits maintaining the concentrations of

combustible gases and oxygen in the circulating gas in the waste-heat boiler.
Furthermore, the present invention prevents adhesion of foreign matters to the sloping flue by maintaining constant the temperature in the prechamber. In addition, the present invention prevents thermal damage to the boiler tubes and the lowering of the heat recovery efficiency in the boiler by maintaining the gas temperature at the entry end of the waste-heat boiler within a certain range.
Also, the present invention prevents an increase in the resistance to the flow of the circulating gas and wear and damage to the boiler tubes due to the floating and bursting of coke from the sloping flue and permits maximizing the recovery of sensible heat from the red-hot coke in the quenching chamber by maintaining constant the quantity of the gas discharged from the quenching tower.
Furthermore, the coke dry quenching methods and systems according to the present invention prevent the splashing of water sprayed over the red-hot coke to the brick by atomizing the water injected into the prechamber and permit uniform dispersion and spraying over the surface of the red-hot coke in the prechamber by mixing the atomized water with the air injected into the prechamber.
Also, the present invention greatly improves the durability of thermometers and significantly decreases the frequency of changing thermometers by measuring the temperature of the red-hot coke observed through the opening of the ring duct with non-contact optical thermometers. Therefore, the present invention greatly decreases the inspection and repair work required in cases of failure thereof.






We claim:
1. A coke dry quenching method that uses a quenching tower comprising a quenching chamber and a prechamber on top thereof, comprises of the steps of charging red-hot coke from above the prechamber, injecting air and/or water or steam into the prechamber, exchanging heat with the sensible heat of the red-hot coke by using an inert gas as a medium in the quenching chamber and recovering heat in the form of steam in a waste-heat boiler, characterized by;
setting the ratio of the adjusted quantity of water or steam injected into the prechamber to the adjusted quantity of air injected into the prechamber so that a constant temperature is maintained in the prechamber,
supplying air to the high-temperature gas discharged from the quenching tower before the gas reaches the waste-heat boiler,
setting the ratio of the adjusted quantity of air supplied to the high-temperature gas before reaching the waste-heat boiler to the adjusted quantity of air injected into the prechamber and water or steam injected into the prechamber so that the concentration of the combustible gas and oxygen in the circulating gas is maintained constant,
adjusting the quantities of air injected into the prechamber and/or water or steam injected into the prechamber and air supplied to the high-temperature gas before reaching the waste-heat boiler so that the quantity of heat input to the waste-heat boiler is maintained constant, and
correcting the target value for the heat input to the waste-heat boiler so that the quantity of the steam generated in the waste-heat boiler becomes equal to the target value.

discharging part of the gas from the waste-heat boiler and supplying to the quenching chamber for bypassing, the bypassed gas (hereinafter referred to as the "bypassed gas") is merged with the gas supplied to the waste-heat boiler,
2. The method as claimed in claim 1, wherein adjusting of air
injected into the prechamber, water or steam injected into the
prechamber and air supplied to the high-temperature gas before
reaching the waste-heat boiler is done so that the quantity of heat
input to the waste-heat boiler is maintained constant by detecting
variation in the quantity of the injected gas supplied to the
quenching chamber and compensating for variation in the
quantity of sensible heat recovered from coke due to the detected
variation in the quantity of the injected gas supplied to the
quenching chamber.
3. The method as claimed in claim 1, wherein, adjusting the
quantity of the bypassed gas is done so that the quantity of the
high-temperature discharge gas from the quenching tower
becomes equal to the target value there for.
4. The method as claimed in any of claims 1 to 3, wherein the air
injected into the prechamber, water or steam injected into the
prechamber and air supplied to the high-temperature gas before
reaching the waste-heat boiler is done so that the quantity of heat
input to the waste-heat boiler is maintained constant by detecting
variation in the quantity of the coke discharged from the
quenching tower and compensating for variation in the quantity of
sensible heat recovered from coke due to the detected variation in
the quantity of coke discharge.
5. The method as claimed in any of claims 1 to 3, wherein the air
injected into the prechamber, water or steam injected into the
prechamber and air supplied to the high-temperature gas before
reaching the waste-heat boiler is done so that the quantity of heat
input to the waste-heat boiler is maintained constant by detecting
variation in the quantity of the circulating gas and compensating
for variation in the quantity of sensible heat recovered from coke
due to the detected variation in the quantity of the circulating gas.

6. The method as claimed in any of claims 1 to 3, wherein air is
supplied to the high-temperature discharge gas from the
quenching tower before the waste gas reaches the waste-heat
boiler and the adjusting of air injected into the prechamber and
water or steam injected into the prechamber is done so that the
quantity of heat input to the waste-heat boiler becomes equal to
the target value by detecting variation in the quantity of air
supplied to the high-temperature gas before reaching the waste-
heat boiler and compensating for variation in the quantity of heat
input to the boiler due to the detected variation in the quantity of
air supplied to the high-temperature gas before reaching the
waste-heat boiler.
7. The method as claimed in any of claims 1 to 3, wherein when the
detected temperature of the gas supplied to the waste-heat boiler
exceeds the predetermined upper or lower limit the gas
temperature at the entry end of the boiler is brought back to
between the upper and lower limits by increasing or decreasing
the flow rate of the circulating gas.


Documents:

883-delnp-2005-abstract.pdf

883-delnp-2005-claims.pdf

883-DELNP-2005-Correspondence-Others-(12-10-2009).pdf

883-delnp-2005-correspondence-others.pdf

883-delnp-2005-correspondence-po.pdf

883-delnp-2005-description (complete).pdf

883-delnp-2005-drawings.pdf

883-delnp-2005-form-1.pdf

883-delnp-2005-form-18.pdf

883-delnp-2005-form-2.pdf

883-DELNP-2005-Form-3-(12-10-2009).pdf

883-delnp-2005-form-3.pdf

883-delnp-2005-gpa.pdf

883-delnp-2005-pct-210.pdf

883-delnp-2005-pct-308.pdf

883-delnp-2005-pct-332.pdf

883-delnp-2005-pct-409.pdf

883-delnp-2005-petition-137.pdf

883-delnp-2005-petition-138.pdf

abstract.jpg


Patent Number 247751
Indian Patent Application Number 883/DELNP/2005
PG Journal Number 19/2011
Publication Date 13-May-2011
Grant Date 11-May-2011
Date of Filing 07-Mar-2005
Name of Patentee NIPPON STEEL CORPORATION
Applicant Address 6-3, OTEMACHI 2-CHOME, CHIYODA-KU, TOKYO 100-8071, JAPAN
Inventors:
# Inventor's Name Inventor's Address
1 YASUTAKA SHIHARA C/O NIPPON CORPORATION TECHNICAL DEVELOPMENT BUREAU, 20-1, SHINTOMI, FUTTSU-SHI, CHIBA 293-8511,JAPAN
2 MASAHIKO YOKOMIZO C/O NIPPON CORPORATION TECHNICAL DEVELOPMENT BUREAU, 20-1, SHINTOMI, FUTTSU-SHI, CHIBA 293-8511,JAPAN
3 ATSUSHI SUZUKI C/O NIPPON CORPORATION TECHNICAL DEVELOPMENT BUREAU, 20-1, SHINTOMI, FUTTSU-SHI, CHIBA 293-8511,JAPAN
PCT International Classification Number C10B 39/02
PCT International Application Number PCT/JP2002/008755
PCT International Filing date 2002-08-29
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 PCT/JP02/008755 2002-08-29 PCT