JPH11116974A - Fuel gasifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel gasifier which can provide high steam pressure in a heat exchanger without increasing the gasificating pressure. SOLUTION: This fuel gasifier 15 comprises: a quench type gasification oven 3 which gasifies a fuel and passes the gasified gas into process water to cool the gas; and a steam generating heat exchanger 8 which generates steam by utilizing waste heat of a gasified gas sent from the quench type gasification oven 3, wherein a COS converter 9 serving also as CO shift, which conducts CO shift and COS conversion of the gasified gas, is provided on an upstream side of a steam generating heat exchanger 8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quench type gasifier for gasifying a fuel and cooling the gasified gas through cooling water, and a steam generator for generating steam by exhaust heat of the gasified gas. The present invention relates to a fuel gasifier including a heat exchanger for use in a fuel system, and particularly to a fuel provided with a CO shift / COS converter for performing both CO shift and COS conversion of a gasified gas upstream of a heat exchanger for steam generation. It relates to a gasifier.

[0002]

2. Description of the Related Art FIG. 3 shows that a fuel composed of a carbon compound is gasified by reacting it with an oxidizing agent and, if necessary, water at a high temperature. Conventional coal gasification combined cycle system (IGCC: Integrated Coa
l Gasification Combined Cycle) is shown schematically.

[0003] A conventional integrated coal gasification combined cycle system 60 equipped with this quench type gasifier is shown in FIG.
A gasification facility 41 for cooling a gas produced by gasifying a fuel with an oxidant (and water if necessary), a gas purification facility 72 connected downstream of the gasification facility 41, and a downstream of the gas purification facility 72. Combined power plant 43 connected to the side,
It is mainly composed of a gasification facility 41 and an air separation facility 44 connected to the combined power generation facility 43.

The gasification equipment 41 reacts a fuel such as pulverized coal or the like with an oxidizing agent (oxygen or air) and, if necessary, water (steam) to gasify the gas, and introduce the fuel into the gasification unit 1. The fuel supply means 10, an oxidant supply pipe 27 (see below) for supplying an oxidant to the gasification section 1, the water supply means 12, and the gasification section 1
It mainly comprises a quench unit 2 for cooling the gasified gas flowing down from the quench unit 2 and the like. The gasification unit 1 and the quench unit 2 constitute a quench type gasification furnace 3.

A liquid reservoir 4 is formed at the bottom of the quench unit 2, and process water 5 is stored in the liquid reservoir 4, and the gasified gas flowing down the gasification unit 1 passes through the process water 5. ) And then sent from the quench unit 2 to the downstream side via the discharge duct 11. The discharge duct 11
The quench unit 2 is provided at a position sufficiently higher than the liquid level of the process water, and connects the quench unit 2 with the downstream gas purification equipment 72.

As shown in FIG. 3, the gas refining equipment 72 includes a scrubber 6, a GGH (gas gas heater) 7, a steam generating heat exchanger 8, and a COS converter provided downstream of the steam generating heat exchanger 8. It mainly comprises a vessel 19, a desulfurization tower 21 downstream of the vessel 19, and a saturator 18. The scrubber 6 is connected to the downstream side of the quench unit 2 of the quench type gasifier 3, and the gasified gas cooled in the quench unit 2 exchanges heat with the steam generating heat exchanger 8 from the scrubber 6 via the GGH 7. The steam is generated to convert the COS into COS in the COS converter 19 (the COS contained in the gasified gas is converted to H ₂ S or the like) and desulfurize in the desulfurization tower 21, and then pass through the saturator 18. Gas turbine 28 of the combined cycle power plant 43
(See below).

The quench gasifier 3, scrubber 6,
FIG. 4 shows the structure of the GGH 7, the steam generating heat exchanger 8, the COS converter 19 and the like in more detail. FIG.
As shown in FIG. 1, a COS converter 19 converts a COS contained in a gasified gas into H ₂ S or the like.
The catalyst is packed. The effective component of the COS catalyst is chromium oxide (Cr ₂ O ₃ ).

[0008] The combined power generation facility 43 includes a gas turbine 28.
(Including the combustor 28a and the compressor 29), a steam turbine 30, an exhaust heat recovery boiler 31, and the like. The gas turbine 28 is connected to the gas purification facility 7 as described above.
The exhaust heat recovery boiler 31 and the steam turbine 30 are installed downstream of the gas turbine 28, and the exhaust heat recovery boiler 31 recovers the residual heat of the exhaust gas from the gas turbine 28 and 30 is driven.

Downstream of the exhaust heat recovery boiler 31, a chimney 3
2 are connected.

The air separation equipment 44 has an air separator 25 for separating high-purity oxygen from air by a cryogenic method or the like.
An outside air introduction pipe 26 for introducing outside air to the air separator 25 is connected to the air separator 25. The air separator 25 is further connected to a downstream side of the compressor 29 of the gas turbine 28 by an air introduction line 23 and connected to a combustor 28 a of the gas turbine 28 by a nitrogen supply line 22. 27, it is connected to the upstream side of the gasification section 1. An outside air introduction pipe 26 is connected to the air separator 25 as shown.

Fuel is supplied to the gasification section 1 by fuel supply means 10. Further, the water supply means 12 supplies an amount of water necessary for the gasification reaction to the gasification unit 1.

On the other hand, in the air separation equipment 44, outside air is introduced into the air separator 25 through the outside air introduction pipe 26. A part of the air compressed by the compressor 29 of the gas turbine 28 is introduced into the air separator 25 through the air introduction line 23. The outside air (air) introduced into the air separator 25 is processed in the air separator 25 by a method such as a cryogenic method, and high-purity oxygen is separated. The separated high-purity oxygen is introduced into the gasification section 1 from the air separator 25 via the oxidant supply line 27 as an oxidant,
On the other hand, the remaining air components from which oxygen was separated (mainly nitrogen)
Is supplied to the combustor 28a of the gas turbine 28 by the nitrogen supply line 22 (see below).

The fuel, moisture and the like introduced into the gasification section 1 are supplied to the air separator 25 of the air separation equipment 44 as described above.
Reacts with an oxidizing agent such as high-purity oxygen supplied through an oxidizing agent supply line 27 and gasifies, thereby generating gasified gas (mainly H ₂ , CO, CO ₂ ).

The gasification gas generated in the gasification section 1 is cooled by dipping under the process water 5 stored in the liquid storage section 4 at the bottom of the quench section 2 and then discharged.
To the downstream scrubbers 6 and GGH 7 to reach the steam generating heat exchanger 8. The temperature of the gasified gas sent to the steam generating heat exchanger 8 is about 200 ° C. (see FIG. 4), and the gasification pressure in this case is about 30 kg / cm ² G. The gasified gas exchanges heat with the boiler water in the steam generating heat exchanger 8. With a gas at 200 ° C., the vapor pressure that can be effectively generated is 10 kg / cm ² G or less.

The gasified gas exiting the steam generating heat exchanger 8 is converted to COS by a downstream COS converter 19 and then desulfurized in a desulfurization tower 21 to remove sulfur contained in the gasified gas. And purified gas. The purified gas is supplied to the desulfurization tower 21
From the top of the gas turbine 28 via the saturator 18
Sent to

When the pressure of the steam obtained as a result of the heat exchange in the steam generating heat exchanger 8 is increased to a higher value, the temperature of the gasified gas sent to the steam generating heat exchanger 8 is further increased. There is a way. Since the temperature of the gasified gas at the outlet of the scrubber 6 is substantially determined by the gasification pressure (the internal pressure of the scrubber 6), for example, in order to generate 20 kg / cm ² G steam, the gasification pressure must be reduced. 70Kg / cm ² G
Must be raised up and down.

The purified gas sent to the gas turbine 28 is
The outside air sucked by the compressor 29 (a part of the outside air sucked by the compressor 29 is sent to the air separator 25 by the air introduction line 23 as described above) to generate electric power. At this time, as described above, the remaining air component (mainly nitrogen) obtained by separating oxygen from the air by the air separator 25 is supplied to the gas turbine 2.
8 is supplied to a gas turbine 28 via a nitrogen supply line 22 to increase the output.

Exhaust gas generated by combustion in the gas turbine 28 is exhausted to the atmosphere via an exhaust heat recovery boiler 31 and a chimney 32. At this time, the exhaust heat recovered by the exhaust heat recovery boiler 31 causes the steam turbine 30 Further power generation is performed.

[0019]

In the case of the fuel gasification and power generation system provided with the quench gasifier described above, the temperature of the gasified gas at the outlet of the scrubber drops to the saturation temperature of the pressure inside the scrubber. . In addition, since the gasified gas enters the steam generating heat exchanger after passing through the GGH, the temperature of the gasified gas entering the steam generating heat exchanger becomes considerably low. Since the pressure of the steam that can be generated by heat exchange with the gasified gas is limited by the temperature of the gasified gas, the pressure of the steam (saturated) generated in the steam generating heat exchanger is also low (as described above). In the example, 1
0 kg / cm ² G or less).

However, when steam at a pressure of 10 kg / cm ² G or more is required, the steam pressure is limited by the gasification gas temperature as described above, and the gasification gas temperature is substantially determined by the gasification pressure. Therefore, to generate higher pressure steam, the gasification pressure must be increased. For example, in the generation steam pressure to 20 Kg / cm ² G, in general, it must raise the gasification pressure to 70 Kg / cm ² G before and after.

However, when the gasification pressure is increased as described above, the pressure applied to the entire system is increased (boiling point in the scrubber is also increased), so that the piping in the system must be configured to withstand the pressure. However, there is a problem that the cost increases.

Accordingly, an object of the present invention is to provide a fuel gasifier capable of obtaining a high steam pressure in a heat exchanger without increasing the gasification pressure.

[0023]

In order to achieve the above object, the present invention is directed to a quench gasifier for gasifying a fuel and cooling the gasified gas through process water. A scrubber that cleanses the chemical gas with water,
A steam generating heat exchanger for generating steam by the exhaust heat of the gasified gas sent from the quench type gasifier, wherein the gasification is performed upstream of the steam generating heat exchanger. A CO shift / COS converter for performing CO shift and COS conversion of gas is provided.

According to the second aspect of the present invention, the CO shift and C
The OS converter is filled with a catalyst that performs both CO shift and COS conversion of the gasified gas.

[0025]

Preferred embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the gasification gas from the quench type gasification furnace is passed through a converter capable of performing both CO shift and COS conversion, and the temperature thereof is raised. Then, the gas is introduced into a heat exchanger to generate high-pressure steam. The fuel gasifier of the present invention is shown schematically with other components of an integrated coal gasification combined cycle system into which it is incorporated.

As shown, the combined gasification combined cycle system 50 equipped with the fuel gasification apparatus of the present invention is a gas for cooling a gas produced by gasifying a fuel together with an oxidizing agent (and water if necessary). Gasification facility 41, a gas purification facility 42 connected downstream of the gasification facility 41, a combined power generation facility 43 connected downstream of the gas purification facility 42, and connected to the gasification facility 41 and the combined power generation facility 43 And an air separation facility 44 provided.

The gasification equipment 41 introduces the fuel into the gasification section 1, which gasifies the fuel such as pulverized coal by reacting it with an oxidizing agent (oxygen or air) and, if necessary, water (steam). The fuel supply means 10, an oxidant supply pipe 27 (see below) for supplying an oxidant to the gasification section 1, the water supply means 12, and the gasification section 1
It mainly comprises a quench unit 2 for cooling the gasified gas flowing down from the quench unit 2 and the like. The gasification unit 1 and the quench unit 2 constitute a quench type gasification furnace 3.

A liquid reservoir 4 is formed at the bottom of the quench unit 2, and process water 5 is stored in the liquid reservoir 4, and gasified gas flowing down the gasification unit 1 passes through the process water 5. ) And then sent from the quench unit 2 to the downstream side via the discharge duct 11. The discharge duct 11
The quench unit 2 is provided at a position sufficiently higher than the liquid level of the process water, and connects the quench unit 2 with the downstream gas purification equipment 42.

As shown in FIG. 1, the gas refining equipment 42 is provided with a scrubber 6, GGH 7, a CO shift / COS converter 9 for performing both CO shift and COS conversion, and a downstream side of the CO shift / COS converter 9. Steam generator 8, the desulfurization tower 21 downstream of the heat exchanger 8, and the saturator 1.
8 mainly.

The scrubber 6 is connected downstream of the quench unit 2 of the quench type gasifier 3, and the gasified gas cooled in the quench unit 2 is supplied from the scrubber 6 via the GGH 7 to the CO2.
Sent to the COS converter 9 for shift and CO shift and C
After the OS conversion process, the heat exchanger 8 for steam generation
Then, the heat is exchanged with the gas turbine 28 and sent to the gas turbine 28 (see below) of the combined cycle power plant 43 via the desulfurization tower 21 and the saturator 18.

FIG. 2 shows the structure of the quench gasifier 3, scrubber 6, GGH 7, COS converter 9 for CO shift, heat exchanger 8 for steam generation, etc. in more detail. As shown in FIG. 2, the CO shift / COS converter 9 of the present embodiment converts the COS contained in the gasified gas into H ₂ S or the like and also shifts the CO shift of the gasified gas. The CO shift / COS catalyst to be performed is filled. The effective component of the CO shift / cos catalyst is, for example, chromium oxide (Cr ₂ O ₃ ) or the like added with cobalt oxide (CoO) and molybdenum oxide (MoO ₃ ).

The quench gasifier 3, scrubber 6, GGH 7, CO shift / COS converter 9 and steam generating heat exchanger 8 shown in FIG. 2 mainly constitute the fuel gasifier 15 of the present invention.

The combined power generation facility 43 includes the gas turbine 28
(Including the combustor 28a and the compressor 29), a steam turbine 30, an exhaust heat recovery boiler 31, and the like. The gas turbine 28 is connected to the gas purification facility 4 as described above.
The exhaust heat recovery boiler 31 and the steam turbine 30 are installed downstream of the gas turbine 28, and the exhaust heat recovery boiler 31 recovers the residual heat of the exhaust gas from the gas turbine 28 and 30 is driven.

Downstream of the exhaust heat recovery boiler 31, a chimney 3
2 are connected.

The air separation equipment 44 has an air separator 25 for separating high-purity oxygen from air by a cryogenic method or the like.
An outside air introduction pipe 26 for introducing outside air to the air separator 25 is connected to the air separator 25. The air separator 25 is further connected to a downstream side of the compressor 29 of the gas turbine 28 by an air introduction line 23, is connected to a combustor 28a of the gas turbine 28 by a nitrogen supply line 22, and has an oxidant supply line. 27, it is connected to the upstream side of the gasification section 1. An outside air introduction pipe 26 is connected to the air separator 25 as shown.

The air separation equipment 44 may be configured to send relatively low-purity oxygen or air to the gasification section 1 as an oxidant.

The fuel is supplied to the gasification section 1 by the fuel supply means 10. Further, the water supply means 12 supplies an amount of water necessary for the gasification reaction to the gasification unit 1.

On the other hand, in the air separation equipment 44, outside air is introduced into the air separator 25 through the outside air introduction pipe 26. A part of the air compressed by the compressor 29 of the gas turbine 28 is introduced into the air separator 25 through the air introduction line 23. The outside air (air) introduced into the air separator 25 is processed in the air separator 25 by a method such as a cryogenic method, and high-purity oxygen is separated. The separated high-purity oxygen is introduced into the gasification section 1 from the air separator 25 via the oxidant supply line 27 as an oxidant,
On the other hand, the remaining air components from which oxygen was separated (mainly nitrogen)
Is supplied to the combustor 28a of the gas turbine 28 by the nitrogen supply line 22 (see below).

The fuel, moisture and the like introduced into the gasification section 1 are supplied to the air separator 25 of the air separation equipment 44 as described above.
Reacts with an oxidizing agent such as high-purity oxygen supplied through an oxidizing agent supply line 27 and gasifies, thereby generating gasified gas (mainly H ₂ , CO, CO ₂ ).

The gasified gas generated in the gasification section 1 is cooled by dipping under the process water 5 stored in the liquid storage section 4 at the bottom of the quench section 2 and then discharged.
To the downstream scrubbers 6 and GGH7 via
It is sent to the shift / cos converter 9. Gasification gas is
The CO shift is performed by the CO shift / COS converter 9 and the COS is converted into H ₂ S or the like. The temperature of the gasified gas itself rises remarkably due to the heat generated in the CO shift, and the temperature of the gasified gas near the outlet of the CO shift / COS converter 9 may be around 400 ° C. at the maximum (FIG. 2).
reference).

The gasified gas that has become high in temperature in this way is then sent to the steam generating heat exchanger 8 on the downstream side, where heat exchange is performed with boiler water, and steam is generated. At this time, since the temperature of the gasified gas can be made relatively high as described above, the pressure of the generated steam (saturation) is set to 100 kg / cm.
^In some cases, it is possible to increase it to ² G or more.

The gasified gas leaving the steam generating heat exchanger 8 is desulfurized in the desulfurization tower 21 on the downstream side to become a purified gas.
The purified gas is sent from the top of the desulfurization tower 21 to the gas turbine 28 via the saturator 18.

The purified gas sent to the gas turbine 28 is burned to generate power. In addition, regarding the treatment and operation of gasified gas in the combined cycle power plant 43 of the present embodiment,
Since it is the same as that of the above-mentioned conventional technology, the description is omitted here.

In summary, according to the present invention, in accordance with the present invention, the gas temperature is raised by simultaneously performing the COS conversion and the CO shift of the gasified gas, and steam is generated by heat exchange between the high-temperature gas and the boiler water. Therefore, high-pressure steam (10 kg / cm ² G or more) can be generated without increasing the gasification pressure. Therefore, not only is it possible to obtain steam at a much higher pressure more easily (that is, without increasing the gasification pressure) than in the case where the gasification pressure is increased to increase the generated steam pressure. Since there is no need to consider the pressure resistance of the entire system, the cost can be reduced.

Further, in this case, heat can be exchanged with a higher temperature gasified gas, so that the steam pressure can be set more flexibly.

[0047]

In summary, the fuel gasifier of the present invention has the following excellent effects.

(1) The gas temperature is raised by simultaneously performing the COS conversion and the CO shift of the gasified gas, and steam is generated by heat exchange between the high-temperature gas and boiler water. High pressure steam can be generated without raising. Therefore, not only is it possible to obtain steam at a much higher pressure more easily (that is, without increasing the gasification pressure) than when the gasification pressure is increased to increase the generated steam pressure, and there is a problem in increasing the gasification pressure. There is no need to consider the pressure resistance of the entire system, which reduces costs.

(2) Since the heat exchange can be performed with the gasified gas having a higher temperature, the steam pressure can be set more flexibly.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of an integrated coal gasification combined cycle system equipped with a fuel gasification device of the present invention.

FIG. 2 is a schematic diagram showing the fuel gasifier of FIG.

FIG. 3 is a schematic diagram of a conventional integrated coal gasification combined cycle system.

FIG. 4 is a partially enlarged schematic view of the integrated coal gasification combined cycle system of FIG. 3;

[Explanation of symbols]

 3 Quench type gasification furnace 8 Heat exchanger for steam generation 9 CO shift combined COS converter 15 Fuel gasifier

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C10K 3/04 C10K 3/04 F01K 23/10 F01K 23/10 C F02C 3/28 F02C 3/28

Claims (2)

[Claims] 1. A quench gasifier for gasifying fuel and cooling the gasified gas through process water, and generating steam by exhaust heat of the gasified gas sent from the quench gasifier. In the fuel gasifier provided with a steam generating heat exchanger to be provided, a CO shift combined COS converter for performing CO shift and COS conversion of the gasified gas is provided upstream of the steam generating heat exchanger. A fuel gasifier characterized by the above-mentioned. 2. The fuel gasifier according to claim 1, wherein the CO shift / COS converter is filled with a catalyst for performing both CO shift and COS conversion of the gasified gas.