Title of Invention	PROCESS OF CONVEYING GRANULAR SOLIDS
Abstract	This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium. To ensure that the pressure between two regions can be reduced at low cost and with little maintenance effort when continuously conveying granular solids, a gaseous medium (9) is injected into a tube through an upwardly directed nozzle (6) at the point where the granular solids are conveyed through a descending line (2) into an ascending line (3).

Title of Invention

PROCESS OF CONVEYING GRANULAR SOLIDS

Abstract

This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium. To ensure that the pressure between two regions can be reduced at low cost and with little maintenance effort when continuously conveying granular solids, a gaseous medium (9) is injected into a tube through an upwardly directed nozzle (6) at the point where the granular solids are conveyed through a descending line (2) into an ascending line (3).

Full Text	-1 - Process of Conveying Granular Solids Description This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium. In a direct-reduction plant, the granular solids, e.g. direct-reduced iron, are brought from an elevated pressure to ambient pressure for further processing in a plant. In this plant, hot direct-reduced iron is conveyed from a fluidized-bed reactor to a pressurized cyclone, from where the granular solids are discharged downwards via a storage bin through a descending line. Inert gas is introduced into the descending line. Via a valve, the descending line is usually connected with an ascending line through which the granular solids are conveyed upwards into an impact pot by supplying inert gas into the ascending line. From said impact pot, the solids are introduced into a briquetting bin while further introducing inert gas. Due to the continuous supply of finegrained solids, a column of these solids is formed in the descending line, which column at the same time represents a pressure barrier. When using the previous solution with the valve, the point of transition from the descending line to the ascending line requires much effort and maintenance, as due to the temperature level and the coarse surface of the granular solids the sealings and the closure body are subject to a very high wear and therefore must be replaced quite often. -2 - In accordance with US-A-2,684,873, fine-grained solids are introduced into an inflow tank, the amount supplied again being regulated by means of a valve. In the inflow tank, a supply of fine-grained solids is formed, into which extends a tube through which the solids are transported into a tank disposed at a higher level. A line pressurizing the inflow tank opens into the inflow tank, whereby the solids are transported through the tube into the tank disposed at a higher level. This known process likewise uses valves for regulating the inflow of solids. For larger amounts of solids to be transported, the inflow tank must be dimensioned correspondingly large, which again makes this apparatus very complex and expensive. 'It is the object underlying the invention that in the above-mentioned process the pressure between two regions be reduced inexpensively and with little maintenance effort while continuously conveying granular solids. In accordance with the invention, this object is solved by the features of claim 1. The inflow of the gaseous medium through an upwardly directed nozzle is effected at the point at which the descending line opens into the ascending line. In order to lose as little kinetic energy as possible, the nozzle orifice for the inflow of gas should expediently be disposed as close as possible to the bulk material to be transported. Due to the line of fall of the bulk material, the nozzle orifice should therefore advantageously be disposed at a distance of 0.5 to 8 times the hydraulic diameter of the nozzle orifice below the point of intersection of the tube axes. Since the fine-grained solids flowing out of the descending line are compacted due to the column standing above the same, it turned out to be advantageous to dispose auxiliary nozzles for loosening up the solids around the pressure line. It turned out to be particularly advantageous when the solids weight in the ascending line lies in the range from 0.3 to 0.8 times the bulk weight, preferably in the range from 0.4 to 0.7 times the bulk weight. 3- With a limited overall height it is expedient to convey the solids via a multi-stage decrease in pressure. Embodiments of the process will be explained by way of example with reference to the drawing, in which: Fig. 1 shows a flow diagram of the process; Fig. 2 shows a detailed representation of Fig. 1, Fig. 3 shows a flow diagram of the multi-stage process. Hot solids are conveyed from a heater into a cyclone (1) at a temperature of 650°C to 800°C. In this cyclone (1), a pressure of 4 to 16 bar exists. The fine-grained solids are discharged downwards via a descending line (2). Into the descending line, inert gas (8a), e.g. nitrogen, is introduced, in order to rinse out the reduction gas. Subsequent to the descending line, the solids are conveyed upwards into an impact pot (4) by means of an ascending line (3) by supplying carrier gas (9), e.g. nitrogen, in which impact pot the pressure lies in the range from 1 to 2 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying inert gas (8b). Due to the continuous inflow of fine-grained solids, a column of these solids is formed in the descending line (2), which column at the same time represents a pressure barrier. This column of solids has a height between 2 and 15 m, and the height thereof can be measured by means of a position meter. The column can be regulated by downwardly draining the same. The flow of solids through the descending line (2) depends on the inert gas inflow (8a), which at the same time influences the height of the solids column in the descending line (2). The pressure at the point where the descending line (2) opens into the ascending line (3) is 4 to 16 bar. -4- Below the point of intersection of the center line of the descending line (2) with the center line of the ascending line (3), carrier gas (9) is injected via a nozzle (6). The pressure at the nozzle orifice (6) is by 0.5 to 1.5 bar higher than the pressure in the cyclone (1). Via the ascending line (3), the solids are conveyed into an impact pot (4), in which the pressure is 1 to 2 bar. The height of the ascending line from the orifice of the descending line (2) to the overflow bin (4) is 10 to 50 m. The diameter of the ascending line (3) may lie between 0.2 and 1.5 m. Around the nozzle orifice (6), a plurality of auxiliary nozzles (7) are disposed, which loosen up the solids and transport the same from the nozzle orifice (6) into the range of influence of the carrier gas (9). The same carrier gas is passed through the nozzles (6) and (7). Fig. 3 shows the conveyance of the solids with a multi-stage decrease in pressure. Hot solids are conveyed from a heater into a cyclone (1) at a temperature of 650°C to 800°C. In this cyclone (1), a pressure of 4 to 16 bar exists. The fine-grained solids are discharged downwards through a descending line (2). Into the descending line, inert gas (8a), e.g. nitrogen, is introduced, in order to rinse out the reduction gas. Subsequent to the descending line (2), the solids are conveyed upwards into an impact pot (4) by means of an ascending line (3) by supplying carrier gas (9), e.g. nitrogen, in which impact pot the pressure lies in the range from 2 to 8 bar. From said impact pot, the solids are conveyed into a second descending line (11) by supplying further inert gas (8b). Subsequent to the descending line, the solids are conveyed upwards into an impact pot (14) by means of a further ascending line (13) by supplying carrier gas (12), e.g. nitrogen, in which impact pot the pressure lies in the range from 1 to 2 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying inert gas (8b). -5- Example 1: To the cyclone (1), 64 t/h direct-reduced iron is supplied with 40,000 Nm3/h H2. The temperature is 730OC, the pressure is 4.5 bar. Upon separation of H2 and solids, the solids are discharged via the descending line (2), which has a diameter of 0.5 m and a length of 16 m. Via line (8a), 70 Nm3/h N2 are supplied for rinsing the H2 contained in the void volume. In the ascending line (3) with a diameter of 0.25 m and a length of 25 m, the solids are conveyed into the impact pot (4) via line (3) by adding 150 Nm3/h N2 through the nozzles (6) and (7). In doing so, the pressure is reduced to 1 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying 30 Nm3/h N2 (8b). Example 2: To the cyclone (1), 64 t/h direct-reduced iron is supplied with 40,000 Nm3/h H2. The temperature is 730°C, the pressure is 4.5 bar. Upon separation of H2 and solids, the solids are discharged via the descending line (2), which has a diameter of 0.5 m and a length of 8 m. Via line (8a), 50 Nm3/h N2 are supplied for rinsing the H2 contained in the void volume. In the ascending line (3) with a diameter of 0.25 m and a length of 10 m, the solids are conveyed into the impact pot (4) via line (3) by adding 150 Nm3/h N2 through the nozzles (6) and (7), in which impact pot a pressure of 3.0 bar is obtained. From said impact pot, the solids are discharged via the descending line (11), which has a diameter of 0.5 m and a length of 8 m. Via lines (8b) and (8c), 50 Nm3/h N2 are supplied for further removing the H2 contained in the void volume. In the ascending line (13) with a diameter of 0.25 m and a length of 15 m, the solids are conveyed into the impact pot by adding 100 Nm3/h N2 (12) via line (13), in which impact pot a pressure of 1 bar exists. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying 30 Nm3/h Nz (8d). 6 WE CLAIM: 1. A process of continuously conveying grantular solids from a first zone through a descending line and via an ascending line to a second zone with a pressure which Is lower than In the first zone, by means of a gaseous medium, wherein the Inflow of the gaseous medium is effected through an upwardly directed nozzle at the point where the descending line opens into the ascending line, characterized in that the first zoneis at a pressure of 4 to 16 bar and that the pressure in the second zone Is 3 to 15 bar lower than the pressure of the first zone, and that the solids weight in the ascending line lies in the range from 0.3 to 0.8 times the bulk weight 2. The process as claimed in claim 1, wherein the nozzle orifice for the inflow of the gaseous medium is disposed at a distance of 0.5 to 8 times the hydraulic diameter of the nozzle orifice below the point of intersection of the tube axes, 7 3. The process as claimed in claim 2, wherein at least one auxiliary nozzle Is disposed beside the conveying nozzle. 4. The process as claimed In claim 1, wherein the solids weight In the ascending line lies in the range from 0.4 to 0.7 times the bulk weight, 5. The process as claimed in claim 1, wherein the soiids are conveyed via at least two descending lines and via at least two ascending lines. This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium. To ensure that the pressure between two regions can be reduced at low cost and with little maintenance effort when continuously conveying granular solids, a gaseous medium (9) is injected into a tube through an upwardly directed nozzle (6) at the point where the granular solids are conveyed through a descending line (2) into an ascending line (3).

Full Text

-1 -
Process of Conveying Granular Solids
Description
This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium.
In a direct-reduction plant, the granular solids, e.g. direct-reduced iron, are brought from an elevated pressure to ambient pressure for further processing in a plant. In this plant, hot direct-reduced iron is conveyed from a fluidized-bed reactor to a pressurized cyclone, from where the granular solids are discharged downwards via a storage bin through a descending line. Inert gas is introduced into the descending line.
Via a valve, the descending line is usually connected with an ascending line through which the granular solids are conveyed upwards into an impact pot by supplying inert gas into the ascending line. From said impact pot, the solids are introduced into a briquetting bin while further introducing inert gas. Due to the continuous supply of finegrained solids, a column of these solids is formed in the descending line, which column at the same time represents a pressure barrier.
When using the previous solution with the valve, the point of transition from the descending line to the ascending line requires much effort and maintenance, as due to the temperature level and the coarse surface of the granular solids the sealings and the closure body are subject to a very high wear and therefore must be replaced quite often.

-2 -
In accordance with US-A-2,684,873, fine-grained solids are introduced into an inflow tank, the amount supplied again being regulated by means of a valve. In the inflow tank, a supply of fine-grained solids is formed, into which extends a tube through which the solids are transported into a tank disposed at a higher level. A line pressurizing the inflow tank opens into the inflow tank, whereby the solids are transported through the tube into the tank disposed at a higher level.
This known process likewise uses valves for regulating the inflow of solids. For larger amounts of solids to be transported, the inflow tank must be dimensioned correspondingly large, which again makes this apparatus very complex and expensive.
'It is the object underlying the invention that in the above-mentioned process the pressure between two regions be reduced inexpensively and with little maintenance effort while continuously conveying granular solids.
In accordance with the invention, this object is solved by the features of claim 1. The inflow of the gaseous medium through an upwardly directed nozzle is effected at the point at which the descending line opens into the ascending line.
In order to lose as little kinetic energy as possible, the nozzle orifice for the inflow of gas should expediently be disposed as close as possible to the bulk material to be transported. Due to the line of fall of the bulk material, the nozzle orifice should therefore advantageously be disposed at a distance of 0.5 to 8 times the hydraulic diameter of the nozzle orifice below the point of intersection of the tube axes.
Since the fine-grained solids flowing out of the descending line are compacted due to the column standing above the same, it turned out to be advantageous to dispose auxiliary nozzles for loosening up the solids around the pressure line.
It turned out to be particularly advantageous when the solids weight in the ascending line lies in the range from 0.3 to 0.8 times the bulk weight, preferably in the range from 0.4 to 0.7 times the bulk weight.

3-
With a limited overall height it is expedient to convey the solids via a multi-stage decrease in pressure.
Embodiments of the process will be explained by way of example with reference to the drawing, in which:
Fig. 1 shows a flow diagram of the process; Fig. 2 shows a detailed representation of Fig. 1,
Fig. 3 shows a flow diagram of the multi-stage process.
Hot solids are conveyed from a heater into a cyclone (1) at a temperature of 650°C to
800°C. In this cyclone (1), a pressure of 4 to 16 bar exists. The fine-grained solids are discharged downwards via a descending line (2). Into the descending line, inert gas (8a), e.g. nitrogen, is introduced, in order to rinse out the reduction gas.
Subsequent to the descending line, the solids are conveyed upwards into an impact pot (4) by means of an ascending line (3) by supplying carrier gas (9), e.g. nitrogen, in which impact pot the pressure lies in the range from 1 to 2 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying inert gas (8b).
Due to the continuous inflow of fine-grained solids, a column of these solids is formed in the descending line (2), which column at the same time represents a pressure barrier. This column of solids has a height between 2 and 15 m, and the height thereof can be measured by means of a position meter. The column can be regulated by downwardly draining the same.
The flow of solids through the descending line (2) depends on the inert gas inflow (8a), which at the same time influences the height of the solids column in the descending line (2). The pressure at the point where the descending line (2) opens into the ascending line (3) is 4 to 16 bar.

-4-
Below the point of intersection of the center line of the descending line (2) with the center line of the ascending line (3), carrier gas (9) is injected via a nozzle (6). The pressure at the nozzle orifice (6) is by 0.5 to 1.5 bar higher than the pressure in the cyclone (1). Via the ascending line (3), the solids are conveyed into an impact pot (4), in which the pressure is 1 to 2 bar. The height of the ascending line from the orifice of the descending line (2) to the overflow bin (4) is 10 to 50 m. The diameter of the ascending line (3) may lie between 0.2 and 1.5 m.
Around the nozzle orifice (6), a plurality of auxiliary nozzles (7) are disposed, which loosen up the solids and transport the same from the nozzle orifice (6) into the range of influence of the carrier gas (9). The same carrier gas is passed through the nozzles (6)
and (7).
Fig. 3 shows the conveyance of the solids with a multi-stage decrease in pressure. Hot solids are conveyed from a heater into a cyclone (1) at a temperature of 650°C to 800°C. In this cyclone (1), a pressure of 4 to 16 bar exists. The fine-grained solids are discharged downwards through a descending line (2). Into the descending line, inert gas (8a), e.g. nitrogen, is introduced, in order to rinse out the reduction gas.
Subsequent to the descending line (2), the solids are conveyed upwards into an impact pot (4) by means of an ascending line (3) by supplying carrier gas (9), e.g. nitrogen, in which impact pot the pressure lies in the range from 2 to 8 bar. From said impact pot, the solids are conveyed into a second descending line (11) by supplying further inert gas (8b).
Subsequent to the descending line, the solids are conveyed upwards into an impact pot (14) by means of a further ascending line (13) by supplying carrier gas (12), e.g. nitrogen, in which impact pot the pressure lies in the range from 1 to 2 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying inert gas (8b).

-5-
Example 1:
To the cyclone (1), 64 t/h direct-reduced iron is supplied with 40,000 Nm3/h H2. The temperature is 730OC, the pressure is 4.5 bar. Upon separation of H2 and solids, the solids are discharged via the descending line (2), which has a diameter of 0.5 m and a length of 16 m. Via line (8a), 70 Nm3/h N2 are supplied for rinsing the H2 contained in the void volume. In the ascending line (3) with a diameter of 0.25 m and a length of 25 m, the solids are conveyed into the impact pot (4) via line (3) by adding 150 Nm3/h N2 through the nozzles (6) and (7). In doing so, the pressure is reduced to 1 bar. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying 30 Nm3/h N2 (8b).
Example 2:
To the cyclone (1), 64 t/h direct-reduced iron is supplied with 40,000 Nm3/h H2. The temperature is 730°C, the pressure is 4.5 bar. Upon separation of H2 and solids, the solids are discharged via the descending line (2), which has a diameter of 0.5 m and a length of 8 m. Via line (8a), 50 Nm3/h N2 are supplied for rinsing the H2 contained in the void volume. In the ascending line (3) with a diameter of 0.25 m and a length of 10 m, the solids are conveyed into the impact pot (4) via line (3) by adding 150 Nm3/h N2 through the nozzles (6) and (7), in which impact pot a pressure of 3.0 bar is obtained. From said impact pot, the solids are discharged via the descending line (11), which has a diameter of 0.5 m and a length of 8 m. Via lines (8b) and (8c), 50 Nm3/h N2 are supplied for further removing the H2 contained in the void volume.
In the ascending line (13) with a diameter of 0.25 m and a length of 15 m, the solids are conveyed into the impact pot by adding 100 Nm3/h N2 (12) via line (13), in which impact pot a pressure of 1 bar exists. From said impact pot, the solids are introduced into a briquetting bin (5) and then into a briquetting press (10) by supplying 30 Nm3/h Nz (8d).

6
WE CLAIM:
1. A process of continuously conveying grantular solids from a
first zone through a descending line and via an ascending
line to a second zone with a pressure which Is lower than In
the first zone, by means of a gaseous medium, wherein the
Inflow of the gaseous medium is effected through an
upwardly directed nozzle at the point where the descending
line opens into the ascending line, characterized in that the
first zoneis at a pressure of 4 to 16 bar and that the pressure
in the second zone Is 3 to 15 bar lower than the pressure of
the first zone, and that the solids weight in the ascending
line lies in the range from 0.3 to 0.8 times the bulk weight
2. The process as claimed in claim 1, wherein the nozzle orifice
for the inflow of the gaseous medium is disposed at a
distance of 0.5 to 8 times the hydraulic diameter of the
nozzle orifice below the point of intersection of the tube
axes,

7
3. The process as claimed in claim 2, wherein at least one
auxiliary nozzle Is disposed beside the conveying nozzle.
4. The process as claimed In claim 1, wherein the solids weight
In the ascending line lies in the range from 0.4 to 0.7 times
the bulk weight,
5. The process as claimed in claim 1, wherein the soiids are
conveyed via at least two descending lines and via at least
two ascending lines.
This invention relates to a process of continuously conveying granular solids from a first zone with a pressure of 4 to 16 bar through a descending line and via an ascending line to a second zone with a pressure which is lower than in the first zone by 3 to 15 bar, by means of a gaseous medium.
To ensure that the pressure between two regions can be reduced at low cost and with little maintenance effort when continuously conveying granular solids, a gaseous medium (9) is injected into a tube through an upwardly directed nozzle (6) at the point where the granular solids are conveyed through a descending line (2) into an ascending line (3).

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Patent Number

205295

Indian Patent Application Number

01054/KOLNP/2003

PG Journal Number

13/2007

Publication Date

30-Mar-2007

Grant Date

30-Mar-2007

Date of Filing

19-Aug-2003

Name of Patentee

OUTOKUMPU OYJ

Applicant Address

RIIHITONTUNTIE 7D 02201 ESPOO,

Inventors:

#	Inventor's Name	Inventor's Address
1	HIRSCH MARTIN	AM VEGELSCHUTZ, 5 61381 FRIEDRICHSDORF,
2	SNEYD STUART	ECKENHEIMER LANDSTRASSE 70 60318 FRANKFURT AM MAIN,
3	FORMANEK LOTHAR	LIBELLENWEG 67, 60529 FRANKFURT AM MAIN,

PCT International Classification Number

B01J/00

PCT International Application Number

PCT/EP02/02630

PCT International Filing date

2002-03-09

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	10116892.6	2001-04-04	Germany