Title of Invention

A MODULE-BASED OXY-FUEL BOILER SYSTEM FOR PRODUCING STEAM FROM WATER

Abstract A boiler system for producing steam from water includes a plurality of serially arranged oxy fuel boilers. Each boiler has an inlet in flow communication with a plurality of tubes. The tubes of each boiler form at least one water wall. Each of the boilers is configured to substantially prevent the introduction of air. Each boiler includes an oxy fuel combustion system including an oxygen supply for supplying oxygen having a purity of greater than 21 percent, a carbon based fuel supply for supplying a carbon based fuel and at least one oxy-fuel burner system for feeding the oxygen and the carbon based fuel into its respective boiler in a near stoichiometric proportion. The oxy fuel system is configured to limit an excess of either the oxygen or the carbon based fuel to a predetermined tolerance. The boiler tubes of each boiler are configured for direct, radiant energy exposure for energy transfer. Each of the boilers is independent of each of the other boilers.
Full Text WO 2006/094182 PCT/US2006/007568
MODULE-BASED OXY-FUEL BOILER
BACKGROUND OF THE INVENTION
[0001] The present invention pertains to an oxygen fueled boiler.
More particularly, the present invention pertains to a module-based oxy-fuel boiler
having a flexible design.
[0002] The advantages of oxy-fuel combustion systems are well
recognized. For example, Gross, U.S. Patent Nos. 6,436,337 and 6,596,220, provide
that some of the advantages of oxy-fuel combustion systems are reduced
environmental pollution (reduced NOx generation), high efficiency, high flame
temperatures and smaller overall physical plant design. The Gross patents, which are
commonly owned with the present application are incorporated herein by reference.
[0003] In order to extract the energy from the fuel, boilers typically
provide some manner in which energy is input to a fluid (through combustion of the
fuel) generally to change the state of the fluid. Energy is then extracted from the fluid
typically in the form of mechanical movement (or kinetic energy). Most boilers use
water as the working fluid to extract energy from the fuel. Water is passed through
tubes that form one or more "walls" or bundles within the boiler.
[0004] Typically, boiler tube walls are designed to transfer energy (in
the form of heat) through the tube wall into the water in several loops and passes of
the walls. As the water passes through the tubes, the water is heated, under pressure
and brought to a high level of energy (and phase change) through super-heat, re-heat
and/or super critical stages. Other stages, such as an economizer unit may also be
used through which water is passed in furnace wall sections prior to super-heat passes.
The water is further heated by convective heat transfer from the heated gases flowing
past the tube bundles (e.g., in the economizer).
[0005] Each of the stages or regions of the boiler is designed to operate
based upon a certain type of heat transfer mechanism or phenomena. For example,
the lower furnace walls are designed for radiant heat transfer whereas the upper
bundles, super-heat, re-heat and economizer sections are designed to function on a
convective heat transfer principle. It will be recognized by those skilled in the art that
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the heat transfer mechanisms are not exclusive of one another as water is heated in the
boiler.
[0006] Although such boiler configurations continue to serve their
applications and purposes well, they do not necessarily take full advantage of the high
flame temperatures and low exhaust gas volumes of oxy-fuel combustion systems.
Accordingly, there is a need for a boiler that uses an oxy-fuel combustion system to
reduce environmental pollution. Desirably, such a boiler design provides high
efficiency (vis-a-vis a high ratio of heat transferred to the working fluid to the heat
available from the combustion products) and makes use of high flame temperatures.
Most desirably, such a boiler configuration can provide a smaller overall physical
plant design.
BRIEF SUMMARY OF THE INVENTION
[0007] A module based boiler system uses a plurality of independent,
serially configured oxy fuel boilers for producing steam from water. The boilers are
configured to carry out a different energy transfer function from one another. A first
or main boiler has a feedwater inlet in flow communication with a plurality of tubes
for carrying the water. The boilers are configured to substantially prevent the
introduction of air.
[0008] The tubes of the main boiler format least one water wall. Each
boiler includes an oxygen supply for supplying oxygen having a purity of greater than
21 percent and preferably at least about 85 percent, a carbon based fuel supply for
supplying a carbon based fuel and at least one oxy-fuel burner system. The burner
system feeds the oxygen and fuel into the boiler in a near stoichiometric proportion to
limit an excess of either the oxygen or the carbon based fuel to a predetermined
tolerance. The tubes of each boiler are configured for direct, radiant energy exposure
for energy transfer from the flame to the water wall tubes. In deference to traditional
nomenclature, reference to water walls is intended to include all boiler tubes in a
radiant zone even though the tubes may carry steam.
[0009] In one embodiment of the boiler system, the second boiler is a
superheat boiler and steam produced by the first boiler is fed directly to the superheat
boiler. Steam exits the superheat boiler and flows to a main steam turbine.
Alternately, the system can include a reheat boiler (which takes feed from the high
pressure steam turbine exhaust), reheats the steam in an oxy fuel boiler similar to the
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main boiler, and feeds a reheat steam turbine. The energy transfer or heating function
of each of the boilers is different from each of the other boilers. That is, in the main
boiler, water is heated from a relatively low energy (enthalpy) value to saturated
steam. In the superheat boiler (if used), the steam is further heated to superheated
conditions. Then, in the reheater, the exhaust steam from the high pressure turbine is
reheated for feeding to a reheat steam turbine.
[0010] The boiler system can include a condenser configured such that
steam exhausts from the high pressure steam turbine to one or more reheat steam
turbines to optionally one or more low pressure turbines and on to the condenser. A
preferred boiler system includes an economizer. The economizer has a gas side that
receives combustion products ("exhaust gases" or "flue gases") from the boilers and a
feedwater side such that the combustion products preheat the boiler feedwater prior to
introducing the feedwater to the main boiler. Following exhaust from the economizer,
the exhaust gases can be used to preheat the oxidizing agent for the oxy-fuel
combustion system, generally tying in to the exhaust gases system prior to any
downstream exhaust gas processing treatment that may be desired. Increased power
can be achieved by parallel groupings of modular boiler systems.
[0011] The oxy-fuel burners can be configured for many different
types of fuel, such as natural gas, oil, coal and other solid fuels. When using a solid
fuel, a portion of the exhaust gases (optionally mixed with oxygen) can be used to
cany the solid fuel into the boilers. The fuel feed gases can be exhaust gases from
downstream of the economizer.
[0012] These and other features and advantages of the present
invention will be apparent from the following detailed description, in conjunction
with the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0013] The benefits and advantages of the present invention will
become more readily apparent to those of ordinary skill in the relevant art after
reviewing the following detailed description and accompanying drawings, wherein:
[0014] FIG. 1 is a schematic flow diagram of a single
reheat/subcritical boiler system having module based oxy fuel boilers embodying the
principles of the present invention;
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[0015] FIG. 2 is a schematic flow diagram of a non-reheat/subcritical
boiler system having module based oxy fuel boilers embodying the principles of the
present invention;
[0016] FIG. 3 is a schematic flow diagram of a single
reheat/supercritical boiler system having module based oxy fuel boilers embodying
the principles of the present invention; and
[0017] FIG. 4 is a schematic flow diagram of a saturated steam boiler
system having a module based oxy fuel boiler embodying the principles of the present
invention.
DETAILED DESCRIPTION OF THE INVENTION
[0018] While the present invention is susceptible of embodiment in
various forms, there is shown in the drawings and will hereinafter be described a
presently preferred embodiment with the understanding that the present disclosure is
to be considered an exemplification of the invention and is not intended to limit the
invention to the specific embodiment illustrated.
[0019] It should be further understood that the title of this section of
this specification, namely, "Detailed Description Of The Invention", relates to a
requirement of the United States Patent Office, and does not imply, nor should be
inferred to limit the subject matter disclosed herein.
[0020] An oxy-fuel combustion system uses essentially pure oxygen,
in combination with a fuel source to produce heat, by flame production (i.e.,
combustion), hi an efficient, environmentally non-adverse manner. Such a
combustion system provides high efficiency (vis-a-vis a high ratio of heat transferred
to the working fluid to the heat available from the combustion products) combustion
and makes use of high flame temperatures. A preferred combustion system uses
oxygen at a relatively high purity (above about 21 percent and preferably at least
about 85 percent oxygen) and as such the overall volume of gas that passes through
the boiler is commensurately lower. Using oxy-fiiel, flame temperatures of greater
than about 3000 °F and up to about 5000°F in the boiler are anticipated.
[0021] Moreover, one of the operational parameters of the present
boiler system is the use of an oxy-fuel combustion system in which relatively pure
oxygen, rather than air, is used as the oxidizing agent. As used herein, oxidizing
agent is intended to mean the gas that carries in the oxygen for combustion. For
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example, when pure (100 percent) oxygen is supplied to the system, the oxygen
comprises 100 percent of the oxidizing agent, whereas when air is used as the
oxidizing agent, oxygen comprises about 21 percent of the oxidizing agent. Thus, the
volume of oxidizing agent that is needed is significantly less (because substantially
only oxygen is used rather than air) than conventional boilers, which results in a gas
volume input (and thus throughput) to the boiler that is lower and a gas flow rate
through the boiler that is lower than conventional boilers. One major advantage
afforded by a lower flow rate and volume is that the overall size of the physical plant
system could be smaller than conventional boiler systems and as such the capital cost
of such a boiler system is anticipated to be commensurately lower.
[0022] One of the functional aspects or functional goals of the present
boiler system is to extract a maximum amount of energy (in the form of heat transfer
from the combustion products/exhaust gases) from the combustion process. This, in
conjunction with the lower flow rate, provides less energy loss at comparable exhaust
gas stack temperatures.
[0023] Another aspect or functional goal of the present invention is to
make the maximum practicable use of the higher flame temperatures. As such, as will
be described below, a considerably larger proportion of the heat transfer from the
combustion products to the boiler tubes and hence to the working fluid (water or
steam) takes place by radiant heat transfer, rather than convective heat transfer.
[0024] A schematic illustration of one embodiment of a boiler system
10 is shown in FIG. 1. The illustrated system 10 is a reheat/subcritical unit. The
system includes three separate and distinct boilers, namely boiler No. 1 (main boiler
12), for producing steam from water, boiler No. 2 (superheat boiler 14) for producing
superheated steam, and boiler No. 3 (reheat boiler 16). Oxygen and fuel are fed to
each of the boilers by oxidizing agent and fuel supply systems 18,20.
[0025] As illustrated schematically, and as will be discussed below,
each of the boilers 12,14,16 includes its own independent oxy-fuel combustion
system 22,24,26. In such an oxy-fuel combustion system, the water walls (tubes T
see boiler 12 in FIG. 1) of each boiler 12-16 are sufficiently exposed to the flame that
the major portion of heat transfer takes place by a radiant heat transfer mechanism
rather than a convective transfer mechanism. That is, the majority of the heat transfer
occurs due to the direct flame exposure of the tubes, rather than the movement of
heated exhaust gases over the tubes. This preferred radiant heat transfer mechanism is
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in sharp contrast to conventional boilers that use large, long and complex exhaust gas
flow-paths (through eonvective passes, convective superheat passes} economizer
sections and the like), to maximize heat transfer trough convective mechanisms.
[0026] The-present boiler system 10 further includes an economizer 28
that transfers energy from boiler: flue gases preferably iriall of the bqijers) to the
main boiler feed water(at the feedwaterlme 30) to preheat me feed water prior to
introduction to the main boiler 12. In a present system, oxygen is produced by
separation from, for example, air in.an oxygen generator 32; Those skilled in the art
will recognize thevarious ways in which oxygen can be-provided for feeding to the
boilers 12-16, for example, that oxygen can be supplied from sources such as storage,
water separation and the like, all of which are within the scope of the present
invention. The fuel supply 20 can be any of various types of fuels and various types
of supplies. For example, the fuel can be a gaseous fuel (e.g., natural gas) , a liquid,
fuel such as fuel oil, diesel oil, or other organic or inorganic based liquid fuels, or a
solid fuel such as coal, agricultural or livestock byproducts. All such oxygen
production and supply configurations IB as;well as all such fuels1 and fuel supply
arrangements 20 are within the scope andspirit of the present invention.
[0027] Returning now to FIG.1, the boiler system 10 is shown as a
supply for an electrial generator 34. To this end, the system includes a
turbine/generator set 36 having the electrical generator 34, a high pressure or main
steam turbine 38, an intermediate pressure steam turbine 40, a low pressure steam
turbine 41 and a condenser 42.
[0028] The system 10 is configured such that feedwater enters the
main boiler through feed water line 30 and is heated as it flows through the boiler 12
water tubes T. In a typical boiler configuration, Water enters the boiler 12 at a
relatively low location in the boiler and rises through the tubes as it is heated. This
serves to maintain the tubes in a flooded state and to maintain the fluid in the tubes at
pressure.
[0029] The heated fluid is separated and saturated steam exits the main
boiler 12 through line 44 and-enters the superheats boiler l4. Here; the steam is further
heated to superheated'conditions, again flowing through- wall tubes. The-superheated
steam exits the superheat boiler 14 through main steam line 46 and enters the high
pressure (main steam) turbine 38. The lower pressure steam exhausts from the high
pressure main steam turbine 38 and is returned to the reheat boiler 16 through the
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reheat steam line 48. The steam exits the reheat boiler 16 through reheat steam flow
line 50 and enters the intermediate pressure turbine. The steam exhausted from the
intermediate turbine 40 flow through cross-over line 43 and enters the low pressure
turbine 41.
[0030] The steam exhausts from the low pressure turbine 41 through
the turbine exhaust line 52 and is fully condensed in the condenser 42 (generally at a
low pressure - lower than atmospheric pressure - so that a maximum amount of
energy is extracted by the turbine 40 from the steam) and is then returned (pumped) to
the main boiler 12 through the economizer 28 which (as set forth above) preheats the
water prior to introduction to the boiler 12.
[0031] As to the fuel circuit, as stated above, fuel and oxidizing agent
are fed into each of the boilers 12,14 and 16 independently. The flue gases all exit
their respective boilers through lines 13,15 and 17, respectively, and enter the
economizer 28 in which the gases preheat the main boiler feedwater. The flue gases
exit the economizer 28 and can be used to preheat the oxidizing agent in oxidizing
agent preheater 60. The exhaust gases, after exiting the economizer 28 are routed to
the oxidizing agent preheater 60 (through line 61) and are then returned (through line
63) for introduction to any necessary downstream processing equipment indicated
generally at 54, such as scrubbers, precipitators or the like. Additionally, in the event
that it is desired, a portion of the flue gas can be recirculated, generally following
oxidizing agent preheat, (through flue gas recirculation lines 56) to the boilers 12-16.
The recirculation lines 56 can also be used as a vehicle (by diversion to fuel carrying
lines 58) to carry fuel into the boilers 12-16 to, for example, carry pulverized coal into
the boilers.
[0032] As will be appreciated by those skilled in the art, because the
flow rate and overall volume of gas entering the boiler (as substantially pure oxygen)
is less than conventional boilers, the flow rate and volume of exhaust or flue gas is
also commensurately less than conventional boilers. As such the downstream
processing equipment 54 can be smaller and less costly than conventional equipment
of an equal sized (power output) power plant.
[0033] A schematic illustration of a second embodiment of a boiler
system 110 is shown in FIG. 2. The illustrated boiler system 110 is a non-
reheat/subcritical unit, and as such, the system includes two separate and distinct
boilers, namely boiler No. 1 (main boiler 112) for producing steam from water and
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boiler No. 2 (superheat boiler 114) for producing superheated steam. There is no
reheat boiler. This system 110 is otherwise similar to the embodiment of the system
10 of FIG. 1 and includes oxidizing agent and fuel supply systems 118,120 (in
independent oxy-fuel combustion systems 122,124) to independently feed each of the
boilers 112,114. The boiler system 110 includes an economizer 128 that uses flue
gas to preheat the feed water prior to introduction to the main boiler 112. Exhaust
gases after the economizer 128 can be used to preheat the oxidizing agent in an
oxidizing agent preheater 160.
[0034] Here too, the boiler system 110 is configured with a
turbine/generator set 136 having an electrical generator 134, a high pressure (or main
steam) turbine 138, an intermediate pressure turbine 140, a low pressure turbine 141
and a condenser 142.
[0035] Feed water enters the main boiler through feed water line 130
and is heated as it flows through the water tubes. The heated fluid is separated and
saturated steam exits the main boiler 112 through line 144 and enters the superheat
boiler 114 where the steam is heated to a superheated condition. The superheated
steam exits the superheat boiler 114 through main steam line 146 and enters the high
pressure turbine 138. Unlike the previous embodiment, in this system 110, the steam
that exits the high pressure turbine 138 traverses through a cross-over line 143 and
enters the intermediate pressure turbine 140 (e.g., there is no reheater). The steam
exits the intermediate pressure turbine 140 and traverses through cross-over 148 and
enters the low pressure turbine 141. The low pressure steam is then exhausted from
the low pressure turbine 141 through low pressure turbine to condenser line 152 and is
then returned (pumped) to the main boiler 112 through the economizer 128.
[0036] As to the fuel circuit, as with the previous embodiment, fuel
and oxidizing agent are fed into each of the boilers 112,114 independently. The flue
gases exit their respective boilers through lines 113 and 115, respectively, and enter
the economizer 128 to preheat the main boiler feedwater. The flue gases exit the
economizer 128 and can be used to preheat the oxidizing agent in oxidizing agent
preheater 160. The exhaust gases, after exiting the economizer 128 are routed to the
oxidizing agent preheater 160 (through line 161) and are then returned (through line
163) for introduction to any necessary downstream processing equipment (as
indicated at 154) following exit from the economizer 128. Flue gas can be
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recirculated 156 and/or used as a vehicle to carry the fuel (e.g., pulverized coal) into
theboilers 112,114.
[0037] Another embodiment of a boiler system 210 is illustrated in
FIG. 3 which shows a single reheat supercritical boiler unit. This system includes two
separate and distinct boilers, namely boiler No. 1 (supercritical main boiler 212) for
producing supercritical steam from water and boiler No. 2 (reheat boiler 216).
Oxygen and fuel (in independent oxy-fuel combustion systems 222,226) are fed to
each of the boilers 212,216 by oxidizing agent and fuel supply systems 218,220.
The boiler system 210 includes an economizer 228 that uses flue gas to preheat the
feed water prior to introduction to the main boiler 212.
[0038] Here too, the boiler system 210 is configured with a
turbine/generator set 236 having an electrical generator 234, a supercritical turbine
238, an intermediate pressure turbine 240, a low pressure turbine 241 and a condenser
242.
[0039] Feed water enters the main boiler 212 through feed water line
230 and is heated as it flows through the water tubes. The heated fluid exits the
supercritcal boiler 212 through the supercritical steam line 246 and enters the
supercritical turbine 238. The fluid (steam) exhausts from the supercritical turbine
238 enters the reheat boiler 216 through reheat line 248 and then flows to the
intermediate pressure turbine 240 through reheat steam line 250. The steam exhausts
from the intermediate turbine 240 through cross-over 243 into low pressure turbine
241. The low pressure steam exits the low pressure turbine 241 and is condensed in
the condenser 242. The condensate is then returned (pumped) to the supercritical
boiler 212 through the economizer 228.
[0040] As to the fuel circuit, as with the previous embodiments, fuel
and oxidizing agent are fed into each of the boilers 212,216 independently. The flue
gases exit their respective boilers through lines 213 and 217, respectively, and enter
the economizer 228 to preheat the main boiler feedwater. The flue gases exit the
economizer 228 and can be used to preheat the oxidizing agent in oxidizing agent
preheater 260. The exhaust gases, after exiting the economizer 228 are routed to the
oxidizing agent preheater 260 (through line 261) and are then returned (through line
263) for introduction to any necessary downstream processing equipment 254 as
necessary following exit from the economizer 228. Flue gas can be recirculated 256
and/or used as a vehicle to carry the fuel (e.g., pulverized coal) into the boilers.
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[0041] Still another embodiment of a boiler system 310 is illustrated in
FIG. 4 which shows a saturated steam boiler unit. This system includes a saturated
steam boiler 312 for producing saturated steam and an oxy-fuel combustion system
322. The boiler system 310 can include an economizer 328 that uses flue gas to
preheat the feed water prior to introduction to the main boiler 312.
[0042] This boiler system 310 is configured to supply saturated steam
to a desired (presently unspecified) downstream process 360. To this end, the system
310 is shown with a "steam requirement" (the downstream process requiring steam)
and a condenser 342, the need for which will depend upon the steam requirement 360.
[0043] Feed water enters the main boiler 312 through feed water line
330 and is heated as it flows through the water tubes. The heated fluid is separated in,
for example, a steam drum 313, into saturated steam and water. The saturated steam
exits the boiler 312 from the drum 313 through the steam line 346 and flows to the
steam requirement 360. The fluid- (steam) can then be condensed in the (optional)
condenser 342, which would then be returned (pumped as feedwater) to the boiler 312
through the economizer 328.
[0044] As to the fuel circuit, as with the previous embodiments, fuel
and oxidizing agent are fed into the boiler 312 through an oxy-fuel combustion
system 322. The flue gases exit the boiler 312 through line 313 and enter the
economizer 328 to preheat the main boiler 312 feedwater. The flue gases exit the
economizer 328 and can be used to preheat the oxidizing agent in oxidizing agent
preheater 370. The exhaust gases, after exiting the economizer 328 are routed to the
oxidizing agent preheater 370 (through line 371) and are then returned (through line
373) for introduction to any necessary downstream processing equipment 354 as
necessary following exit from the economizer 328. Flue gas can be recirculated 356
and/or used as a vehicle to carry the fuel (e.g., pulverized coal) into the boiler 312.
Oxygen is supplied by oxidizing agent supply 318 and fuel is supplied by fuel supply
320.
[0045] In each of the embodiments of the boiler system 10,110,210,
310, the boiler(s) are essentially stand alone units that are constructed to operate so as
to maximize heat transfer that occurs by way of a radiant heat transfer mechanism.
As such, the boilers are relatively small (to ensure effective exposure of the water
walls/tubes T), or at least smaller than a comparable conventional boiler that relies on
convective heat transfer. Those skilled in the art will recognize that although each of
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the boilers in each system (for example the main boiler 12, superheat boiler 14 and
reheat boiler 16 of the single reheat boiler system 10) is shown and described as a
single boiler unit, it is anticipated that each of these boilers can be configured as
multiple units in series. Again, for example, the main boiler 12 could be configured
as two or three smaller boilers in series. In addition, although each of the boilers is
shown as having one oxy-fuel burner, it is anticipated that each boiler may have
multiple burners, as need. It will be appreciated that the use of a single boiler or
multiple boilers for each of the heating stages and the use of a single burner or
multiple burners for each boiler will further enhance the ability to control the heat
input to the individual boilers to more efficiently control the overall process and
steam conditions.
[0046] As provided in the above-noted patents to Gross, energy is
input to the boilers by the oxy-fuel combustion systems. Using such an arrangement,
the principle mode of heat transfer to the furnace is radiant, with some convective
heat transfer. Because these burners (and the oxy-fuel systems generally) produce
high flame temperatures, the oxy fuel combustion systems provide this efficient
radiant heat transfer. The geometry of the boiler (e.g., direct flame exposure of the
boiler tubes) further increases the heat transfer rate by maximizing the metal surface
area over which heat transfer from the flame to the metal occurs.
[0047] Advantageously, the present boilers maximize the use of
radiant heat transfer in combination with the use of oxy-fuel combustion which may
permit the boiler to be physically smaller than a conventional boiler of an about equal
size (power output). That is, because essentially pure oxygen (rather than air) is used
as the oxidizing agent, the entirety of the oxidizing agent is available for combustion
and the volume of gas input to the boiler is about 21 percent of the volume of gas that
would be needed if air is used as the oxidizing agent to provide the oxygen necessary
for combustion. Thus, the boiler could be considerably smaller because essentially
pure oxygen rather than air is used.
[0048] In addition, the fuel/oxygen mixture (again, rather than a
fuel/air mixture) results in higher flame temperatures in the boilers. Using oxy-fuel,
flame temperatures of about 5000°F in the boiler can be achieved. This is higher, by
about 1500°F to 2000°F, than conventional boilers. It has also been observed that
using oxy-fuel, in conjunction with these higher flame temperatures, results in a
highly efficient process.
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[0049] In present boiler systems using natural gas as fuel, the
oxygen/natural gas proportions are about 2.36:1. This ratio will vary depending upon
the purity of the oxygen supply and the nature of the fuel. For example, under ideal
conditions of 100 percent pure oxygen, the ratio is theoretically calculated to be
2.056:1. However, in that the oxygen supply can have a percentage of non-oxygen
constituents (generally up to about 15 percent) and natural gas may not always be 100
percent pure, such a variation is expected. As such, those skilled in the art will
appreciate and understand that the ratios may vary slightly, but the basis for
calculating the ratios, that is approximately stoichiometric proportions of fuel and
oxygen, remain true.
[0050] This proportion of oxygen to fuel provides a number of
advantages. For example, approximately stoichiometric proportions provide for
complete combustion of the fuel, thus resulting in a substantially smaller volume of
NOx and other noxious off-gas emissions.
[0051] It is important to note that accurately controlling the ratio of
oxygen to fuel assures complete combustion of the fuel. This is in stark contrast to
conventional (for example, fossil fueled electric generation power plants), that
struggle with LOI (loss on ignition). Essentially, LOI equates to incomplete
combustion of the fuel. The present boiler systems 10,110,210, 310, on the other
hand, use substantially pure oxygen, in tightly controlled near stoichiometric
proportion to the fuel (with boilers that are "tight", that is, configured to essentially
prevent the introduction of air), in an attempt to minimize and possibly eliminate
these losses. In addition, when using these burners (in an oxy-fuel system), the only
theoretical NOx available is from fuel-borne nitrogen, rather than that which could
otherwise result from combustion using air. Thus, NOx, if not completely eliminated
is reduced to an insignificant amount compared to conventional combustion systems
[0052] Moreover, because radiant heat transfer is the desired heat
transfer mechanism, less reliance is made on convective (gas) passes within the boiler.
This too permits a smaller, less complex boiler design. These design considerations
allow the boilers to be configured as stand alone, modular units. That is, referring to
FIG. 1, a stand alone main boiler 12 can be grouped with a stand alone superheat
boiler 14 which can grouped with a stand alone reheat boiler 16. Likewise, referring
to FIG. 3, a stand alone supercritical main boiler 212 can be grouped with a stand
alone reheat boiler 216 as the core of the boiler system 210. This stand alone
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configuration gives control advantages over conventional systems where the
temperature of the superheated steam is controlled by atemperation (desuperheat).
The desuperheat process cools the superheated steam by the addition of water or
steam (as vapor or spray) and drops the efficiency of the system and can be eliminated
by using separate boilers for boiling and superheating. There are also advantages
during turn down operation (operating at less capacity than design capacity). Under
turn down conditions the heat input into the boiling region can be controlled
independently of the heat input into the superheat region or reheat region and leads to
more efficient operation.
[0053] A study of heat and mass balances around the various boiler
configurations shows that the projected boiler efficiencies are quite high, and
considerably higher than known boiler systems. For example, in the first,
reheat/subcritical unit, in the main boiler, the change in enthalpy of the water inlet to
the steam outlet is about 1.95E9 BTU/hr with a fuel input enthalpy of about 2.08E9
BTU/hr. In the superheat boiler, the change in enthalpy of the steam inlet to the steam
outlet is about 7.30E8 BTU/hr with a fuel input enthalpy of about 8.32E8 BTU/hr,
and in the reheat boiler, the change in enthalpy of the water inlet to the steam outlet is
about 5.52E8 BTU/hr with a fuel input enthalpy of about 6.22E8 BTU/hr. These
result in efficiencies in the main boiler, the superheat boiler and the reheat boiler of
93.8% (including economizer gain), 87.8% and 88.7%, respectively.
[0054] Likewise, in the second, non-reheat, subcritical unit, in the
main boiler, the change in enthalpy of the water inlet to the steam outlet is about
1.99E9 BTU/hr with a fuel input enthalpy of about 1.97E9 BTU/hr. In the superheat
boiler, the change in enthalpy of the steam inlet to the steam outlet is about 1.22E9
BTU/hr with a fuel input enthalpy of about 1.60E9 BTU/hr. These result in
efficiencies in the main boiler and the superheat boiler of 101.0% (including
economizer gain) and 76.2%, respectively. It is important to note that the economizer
is included in the calculations for the main boiler (which takes exhaust from both the
boiler and superheating boiler) and as such, credit is taken for the exhaust gas energy
from the superheating boiler which allows the efficiency to appear to be greater than
100% (which it is not).
[0055] In the third, reheat-supercritical boiler, in the supercritical main
boiler, the change in enthalpy of the water inlet to the steam outlet is about 2.37E9
BTU/hr with a fuel input enthalpy of about 2.72E9 BTU/hr. In the reheat boiler, the
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WO 2006/094182 PCT/US2006/007568
change in enthalpy of the steam inlet to the steam outlet is about 6.23E8 BTU/hr with
a fuel input enthalpy of about 7.24E8 BTU/hr. These result in efficiencies in the
supercritical main boiler and the reheat boiler of 87.2% (including economizer gain)
and 86.0%, respectively.
[0056] In the last or the saturated steam boiler system, the change in
enthalpy of the water inlet to the steam outlet is about 3.42E9 BTU/hr with a fuel
input enthalpy of about 3.73E9 BTU/hr. There is a blowdown loss of about 0.13E8
BTU/hr. This result in an efficiency in the main boiler of 91.7%.
[0057] Table 1 below shows partial mass and energy balance
components for the reheat/subcritical unit broken down by boilers. Table 2 shows
partial mass and energy balance components for the non-reheat/subcritical unit broken
down by boilers, Table 3 shows partial mass and energy balance components for the
reheat-supercritical boiler unit broken down by boilers, and Table 4 shows partial
mass and energy components for the saturated steam boiler unit. It should be noted
that the partial mass and energy balance values in Table 3 for the reheat-supercritical
boiler unit show first and second boiler sections, which have been added together to
determine the efficiency and to conform to the schematic illustration of FIG. 3. In
each of the partial mass and energy balance value summaries in Tables 1-3, the
specific and total enthalpy values are water inlet to the respective first combustion
section before the economizer.
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WO 2006/094182 PCT/US2006/007568
15
Table 1 Partial Mass and Energy Balance for Reheat/Subcritical Boiler System


WO 2006/094182 PCT/US2006/007568
Table 3 Partial Mass and Energy Balance for Reheat/Supercritical Boiler System

[0058] As set forth above, each of the boiler systems departs from
conventional processes in two principal areas. First, conventional combustion
processes use air (as an oxidizing agent to supply oxygen), rather than essentially pure
oxygen, for combustion. The oxygen component of air (about 21 percent) is used in
combustion, while the remaining components (essentially nitrogen) are heated in and
exhausted from the furnace. Second, the present process uses oxygen and fuel in a
near stoichiometric proportion to one another (within a tolerance of about ±5 percent).
That is, only enough oxidizing agent is fed in proportion to the fuel to assure complete
combustion of the fuel within the predetermined tolerance. And, this is carried out in
multiple boiler components or modules configured as a coordinated system, each
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WO 2006/094182 PCT/US2006/007568
module heating in a respective, desired stage (e.g., main boiler, superheat region,
reheat region).
[0059] Many advantages and benefits are achieved using the present
combustion system. It has been observed, as will be described below, that fuel
consumption, to produce an equivalent amount of power or heat is reduced.
Significantly, this can provide for a tremendous reduction in the amount of pollution
that results. Again, in certain applications, the emission of NOx can be reduced to
essentially zero.
[0060] In addition, it has been observed that because the throughput of
gases is considerably lower than conventional boilers the volume of discharge of
exhaust gases is commensurately lower. In fact, in that the input of oxidizing agent
(oxygen in the present system compared to air in conventional system) is about 21
percent of conventional systems, the discharge is also about 21 percent of
conventional systems (with solid fuels this may be, for example, 40 percent in that
there is a quantity of motivating gas needed to move the solid fuel into the boiler).
And, it is anticipated that the principle constituent of the discharge gases will be water
(as vapor) which can be condensed or otherwise released and CO2. It is also
anticipated that the CO2 is captured in concentrated form for use in other industrial
and/or commercial applications and/or for sequestration.
[0061] It has also been found that using a fuel/oxygen mixture (again,
rather than a fuel/air mixture) results in higher flame temperatures as discussed above.
Using oxy-fuel, flame temperatures of about 5000°F can be achieved. This is higher,
by about 1500°F to 2000°F, than other, known boilers. It has also been observed that
using oxy-fuel, in conjunction with these higher flame temperatures, results in an
extremely highly efficient process.
[0062] In the present disclosure, the words "a" or "an" are to be taken
to include both the singular and the plural. Conversely, any reference to plural items
shall, where appropriate, include the singular.
[0063] From the foregoing it will be observed that numerous
modifications and variations can be effectuated without departing from the true spirit
and scope of the novel concepts of the present invention. It is to be understood that
no limitation with respect to the specific embodiments illustrated is intended or should
be inferred. The disclosure is intended to cover by the appended claims all such
modifications as fall within the scope of the claims.
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WO 2006/094182 PCT/US2006/007568
CLAIMS
What is claimed is:
1. A module based oxy-mel boiler system for producing steam from
water, comprising:
a first boiler having a feedwater inlet in flow communication with a plurality
of tubes for carrying the water, the tubes forming at least one water wall, the first
boiler configured to substantially prevent the introduction of air;
a first boiler oxygen supply for supplying oxygen having a purity of
greater than 21 percent;
a first boiler carbon based fuel supply for supplying a carbon based
fuel;
at least one first boiler oxy-fuel burner system, the first boiler oxy-fuel
burner system feeding the oxygen and the carbon based fuel into the first
boiler in a near stoichiometric proportion to one another to limit an excess of
either the oxygen or the carbon based fuel to a predetermined tolerance,
wherein the first boiler tubes are configured for direct, radiant energy
exposure for energy transfer to the water to produce steam;
a second boiler having a plurality of tubes, the second boiler being in series
with the first boiler and configured to carry out a different energy transfer function
than the first boiler, the tubes in the second boiler forming at least one tube wall, the
second boiler configured to substantially prevent the introduction of air;
a second boiler oxygen supply for supplying oxygen having a purity of
greater then 21 percent;
a second boiler carbon based fuel supply for supplying a carbon based
fuel;
at least one second boiler oxy-fuel burner, the second boiler oxy-fuel
burner feeding the oxygen and the carbon based fuel into the second boiler in a
near stoichiometric proportion to one another to limit an excess of either the
oxygen or the carbon based fuel to a predetermined tolerance,
wherein the second boiler tubes are configured for direct, radiant
energy exposure for energy transfer to produce steam, and
wherein the first and second boilers are independent of and in series with one
another.
18

WO 2006/094182 PCT/US2006/007568
2. The module based oxy-fuel boiler system in accordance with claim 1
wherein the first boiler oxygen supply supplies oxygen having a purity of about 85
percent.
3. The module based oxy-fuel boiler system in accordance with claim 1
wherein the second boiler oxygen supply supplies oxygen having a purity of about 85
percent.
4. The module based oxy-fuel boiler system in accordance with claim 1
wherein the first boiler is a main boiler and the second boiler is a superheat boiler and
wherein steam produced by the first boiler is fed directly to the superheat boiler.
5. The module based oxy-fuel boiler system in accordance with claim 4
including a steam turbine, wherein steam exiting the superheat boiler is fed to the
steam turbine.
6. The module based oxy-fuel boiler system in accordance with claim 5
including a reheater boiler, wherein the reheater boiler has a plurality of tubes, the
reheater boiler being in series with the main boiler and the superheat boiler and
configured to carry out a different energy transfer function than the main boiler arid
the superheat boiler, the tubes hi the reheat boiler forming at least one tube wall, the
reheater boiler configured to substantially prevent the introduction of air, the reheat
boiler system including an oxygen supply for supplying oxygen having a purity of
greater than 21 percent, a carbon based fuel supply for supplying a carbon based fuel
and at least one reheat boiler oxy-fuel burner, the oxy-fuel burner feeding the oxygen
and the carbon based fuel into the reheat boiler in a near stoichiometric proportion to
one another to limit an excess of either the oxygen or the carbon based fuel to a
predetermined tolerance, wherein the reheat boiler tubes are configured for direct,
radiant energy exposure for energy transfer to superheat the steam and wherein the
reheat boiler is independent of the main boiler and the superheat boiler, the reheat
boiler being fed from an exhaust of the steam turbine and configured to produce
steam.
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WO 2006/094182 PCT/US2006/007568
7. The module based oxy-fuel boiler system in accordance with claim 6
wherein the reheater boiler oxygen supply supplies oxygen having a purity of about
85 percent.
8. The module based oxy-fuel boiler system in accordance with claim 6
including an intermediate pressure turbine, wherein steam produced by the reheat
boiler is fed to the intermediate pressure turbine.
9. The module based oxy-fuel boiler system in accordance with claim 8
including a low pressure turbine, wherein steam exhausted from the intermediate
pressure turbine is fed to the low pressure turbine and wherein steam exhausted from
the low pressure turbine is fed to a condenser.
10. The module based oxy-fuel boiler system in accordance with claim 1
including an economizer having a gas side and a feedwater side, wherein exhaust
gases from the first and second boiler flow into the economizer gas side and wherein
feedwater flows through the economizer and into the feedwater inlet.
11. The module based oxy-fuel boiler system in accordance with claim 10
wherein the first and second boilers are solid fuel boilers and wherein a portion of the
exhaust gases is used to carry solid fuel into at least one of the boilers.
12. The module based oxy-fuel boiler system in accordance with claim 11
wherein a portion of the exhaust gases is used to carry solid fuel into the first and
seconds boilers.
13. The module based oxy-fuel boiler system in accordance with claim 11
wherein the portion of the exhaust gases that is used to carry solid fuel into at least
one of the boilers exhausts from an exhaust gas flowpath downstream of the
economizer.
14. The module based oxy-fuel boiler system in accordance with claim 10
wherein exhaust gases exhausting from the economizer gas side preheat the oxygen
supply for the first and second boiler oxygen supplies.
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WO 2006/094182 PCT/US2006/007568
15. The module based oxy-fuel boiler system in accordance with claim 1
wherein the first boiler is a main boiler and the second boiler is a reheat boiler and
including a main steam turbine and an intermediate pressure turbine, wherein steam
exiting the main boiler is fed to the main steam turbine, steam exhausted from the
main turbine is fed to the reheat boiler and steam exiting the reheat boiler is fed to the
intermediate pressure turbine.
16. The module based oxy-fuel boiler system in accordance with claim 15
including a low pressure turbine, wherein steam exhausts from the intermediate
pressure turbine to the low pressure turbine,
17. The module based oxy-fuel boiler system in accordance with claim 16
including a condenser and wherein steam exhausting from the low pressure turbine
exhausts to the condenser.
18. The module based oxy-fuel boiler system in accordance with claim 15
including an economizer having a gas side and a feedwater side, wherein exhaust
gases from the main and reheat boiler exhaust through the economizer and wherein
feedwater from the condenser flow through the economizer and into the feedwater
inlet.
19. The module based oxy-fuel boiler system in accordance with claim 18
wherein the main and reheat boilers are solid fuel boilers and wherein a portion of the
exhaust gases is used to carry solid fuel into at least one of the boilers.
20. The module based oxy-fuel boiler system in accordance with claim 19
wherein a portion of the exhaust gases is used to carry solid fuel into the main and
reheat boilers.
21. The module based oxy-fuel boiler system in accordance with claim 20
wherein the portion of the exhaust gases that is used to carry solid fuel into at least
one of the boilers exhausts from an exhaust gas flowpath downstream of the
economizer.
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WO 2006/094182 PCT/US2006/007568
22. The module based oxy-fuel boiler system in accordance with claim 18
wherein exhaust gases exhausting from the economizer gas side preheat the oxygen
for the main and reheat boiler oxygen supplies.
23. A boiler system for producing steam from water, comprising a
plurality of serially arranged boilers, each boiler having a inlet in flow communication
with a plurality of tubes for carrying the water, the tubes forming at least one tube
wall, each of the boilers configured to substantially prevent the introduction of air,
each of the boilers including an oxygen supply for supplying oxygen having a purity
of greater than 21 percent, a carbon based fuel supply for supplying a carbon based
fuel and at least one oxy-fuel burner system for feeding the oxygen and the carbon
based fuel into its respective boiler in a near stoichiometric proportion to limit an
excess of either the oxygen or the carbon based fuel to a predetermined tolerance,
wherein the boiler tubes of each boiler are configured for direct, radiant energy
exposure for energy transfer, wherein each of the boilers is independent of each of the
other boilers.
24. The boiler system in accordance with claim 23 wherein the boiler
oxygen supplies each supply oxygen having a purity of about 85 percent
25. The boiler system in accordance with claim 23 including multiple
pluralities of serially arranged boilers, each of the multiples being in parallel with one
another.
26. The boiler system in accordance with claim 25 wherein each of the
multiples is similar to each of the others of the multiples.
22

(57) Abstract: A boiler system for produc-
ing steam from water includes a plurality of
serially arranged oxy fuel boilers. Each boiler
has an inlet in flow communication with a plu-
rality of tubes. The tubes of each boiler form
at least one water wall. Each of the boilers
is configured to substantially prevent the in-
troduction of air. Each boiler includes an oxy
fuel combustion system including an oxygen
supply for supplying oxygen having a purity
of greater than 21 percent, a carbon based fuel
supply for supplying a carbon based fuel and
at least one oxy-fuel burner system for feeding
the oxygen and the carbon based fuel into its
respective boiler in a near stoichiometric pro-
portion. The oxy fuel system is configured to
limit an excess of either the oxygen or the car-
bon based fuel to a predetermined tolerance.
The boiler tubes of each boiler are configured
for direct, radiant energy exposure for energy
transfer. Each of the boilers is independent of
each of the other boilers.

Documents:

02337-kolnp-2007-abstract.pdf

02337-kolnp-2007-assignment.pdf

02337-kolnp-2007-claims.pdf

02337-kolnp-2007-correspondence others 1.1.pdf

02337-kolnp-2007-correspondence others 1.2.pdf

02337-kolnp-2007-correspondence others.pdf

02337-kolnp-2007-description complete.pdf

02337-kolnp-2007-drawings.pdf

02337-kolnp-2007-form 1.pdf

02337-kolnp-2007-form 18.pdf

02337-kolnp-2007-form 3 1.1.pdf

02337-kolnp-2007-form 3.pdf

02337-kolnp-2007-form 5.pdf

02337-kolnp-2007-gpa.pdf

02337-kolnp-2007-international publication.pdf

02337-kolnp-2007-pct priority.pdf

2337-KOLNP-2007-ABSTRACT 1.1.pdf

2337-KOLNP-2007-AMANDED CLAIMS.pdf

2337-KOLNP-2007-AMANDED PAGES OF SPECIFICATION.pdf

2337-KOLNP-2007-ASSIGNMENT 1.1.pdf

2337-KOLNP-2007-ASSIGNMENT.pdf

2337-KOLNP-2007-CORRESPONDENCE 1.1.pdf

2337-KOLNP-2007-CORRESPONDENCE 1.3.pdf

2337-KOLNP-2007-CORRESPONDENCE-1.2.pdf

2337-KOLNP-2007-CORRESPONDENCE-1.4.pdf

2337-KOLNP-2007-CORRESPONDENCE.pdf

2337-KOLNP-2007-DESCRIPTION (COMPLETE) 1.1.pdf

2337-KOLNP-2007-DRAWINGS 1.1.pdf

2337-KOLNP-2007-EXAMINATION REPORT REPLY RECIEVED.pdf

2337-KOLNP-2007-EXAMINATION REPORT.pdf

2337-KOLNP-2007-FORM 1 1.1.pdf

2337-KOLNP-2007-FORM 18.pdf

2337-KOLNP-2007-FORM 2.pdf

2337-KOLNP-2007-FORM 3 1.2.pdf

2337-KOLNP-2007-FORM 3 1.3.pdf

2337-KOLNP-2007-FORM 3-1.4.pdf

2337-KOLNP-2007-FORM 3.pdf

2337-KOLNP-2007-FORM 5.pdf

2337-KOLNP-2007-FORM-27-1.1.pdf

2337-KOLNP-2007-FORM-27.pdf

2337-KOLNP-2007-GPA.pdf

2337-KOLNP-2007-GRANTED-ABSTRACT.pdf

2337-KOLNP-2007-GRANTED-CLAIMS.pdf

2337-KOLNP-2007-GRANTED-DESCRIPTION (COMPLETE).pdf

2337-KOLNP-2007-GRANTED-DRAWINGS.pdf

2337-KOLNP-2007-GRANTED-FORM 1.pdf

2337-KOLNP-2007-GRANTED-FORM 2.pdf

2337-KOLNP-2007-GRANTED-LETTER PATENT.pdf

2337-KOLNP-2007-GRANTED-SPECIFICATION.pdf

2337-KOLNP-2007-OTHERS-1.1.pdf

2337-kolnp-2007-others.pdf

2337-KOLNP-2007-PA.pdf

2337-KOLNP-2007-PETITION UNDER RULE 137.pdf

2337-KOLNP-2007-REPLY TO EXAMINATION REPORT-1.1.pdf

abstract-02337-kolnp-2007.jpg


Patent Number 248762
Indian Patent Application Number 2337/KOLNP/2007
PG Journal Number 34/2011
Publication Date 26-Aug-2011
Grant Date 22-Aug-2011
Date of Filing 25-Jun-2007
Name of Patentee JUPITER OXYGEN CORPORATION
Applicant Address 4825 N. SCOTT STREET, SCHILLER-PARK, IL
Inventors:
# Inventor's Name Inventor's Address
1 PARTICK BRIAN R 1913 W. HURON, CHICAGO, ILLINOIS 60622
2 ORYSCHYN DANYLO, B 2515 GREEN STREET, PHILOMATH, OREGON 97370 USA
3 SUMMERS, CATHY A 1120 LAWNBRIDGE STREET SW, ALBANY, OR 97321 USA
4 OCHS, TOM, L 1509 QUEEN AVENUE, SW, ALBANY, OREGON 97231 USA
PCT International Classification Number F23C 10/00
PCT International Application Number PCT/US06/007568
PCT International Filing date 2006-03-01
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 11/070177 2005-03-01 U.S.A.