JPH1122905A - Return flow type convection crude gas cooler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a duct preventive against choking, highly efficient in recovery of heat, and economize on the heat-transfer area of a heating tube. SOLUTION: In this crude gas cooler 7 crude gas obtained by gasification of fuel such as coal is put in contact with a vaporizer 3 and an economizer 4 and the heat of gasification is recovered by transfer of heat. In this instance the cooler body 2 is demarcated into an upward flow side water-cooled wall part 5a through which the crude gas is passed upward and a downward flow side water-cooled wall part 5b through which the crude gas is passed downward and discharged. The upward flow side water-cooled wall part 5a is provided with a vaporizer 3 and the downward flow side water-cooled wall part 5b, with an economizer 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a convection-type crude gas cooler for recovering gasification heat by contacting a crude gas obtained by gasifying a fuel such as coal with a heat transfer tube, and in particular, relates to an evaporative tube. The present invention relates to a convection-type crude gas cooler which is installed near an inlet of a cooler to recover heat by an upward flow and installs a economizer at a downward flow portion of the cooler to recover heat by a downward flow.

[0002]

2. Description of the Related Art An integrated coal gasification combined cycle (IGCC) system is used in which a fuel such as coal is gasified in a gasifier to generate a high-temperature crude gas, which is used for power generation and the like.
In the cation Combined Cycle, a crude gas cooler for recovering gasification heat from the crude gas is provided connected to the outlet of the gasification furnace.

FIG. 4 shows a conventional integrated coal gasification combined cycle system 60 having a Texaco method coal gasification facility (see reference numeral 40). In the case of this type of coal gasification equipment 40, the crude gas cooler is composed of a radiation type crude gas cooler 6 and a convection type crude gas cooler 27 as shown, and is provided downstream of the gasification furnace 5. The radiation type crude gas cooler 6 and the convection type crude gas cooler 27 are connected in order.

The crude gas outlet 6a of the radiant crude gas cooler 6 of the Texaco type coal gasification facility 40 is installed below the radiant crude gas cooler 6, as shown in the figure. For this reason, the convection type crude gas cooler 27 connected downstream of the radiation type crude gas cooler 6 is of a return flow type (after the crude gas introduced from the lower part of the cooler rises, it returns near the top of the cooler). 3A or 3B, the internal structure of the convective crude gas cooler 27 is generally as shown in FIG. 3A or 3B (in FIG. 3B, Convection type crude gas cooler 37).

That is, for example, in the case of a convection type coarse gas cooler 27 of the type shown in FIG.
7 is provided with a coarse gas inlet 28 and a coarse gas outlet 29 provided at the lower part thereof and an ascending flow side duct 25a extending in the axial direction.
And a downflow-side water cooling wall 25b.
After the coarse gas introduced from the ascending flow rises in the upflow duct 25a, it returns near the top of the cooler body, descends the downflow water cooling wall 25b, and is discharged from the coarse gas discharge port 29. ing.

The evaporating tube 23 as a heat transfer tube for recovering the gasification heat of the crude gas by heat transfer is provided on the downflow side water cooling wall 25b.
A economizer 24 is provided as shown. The width of the upflow duct 25a is relatively small because the width of the cooler body needs to be as small as possible.

On the other hand, in the case of a convection-type crude gas cooler 37 of the type shown in FIG. 3B, the convection-type crude gas cooler 37 has a coarse gas inlet 38 and a coarse gas outlet 39 provided at its lower part. It has an upflow-side water cooling wall 35a and a downflow-side duct 35b extending in the axial direction, and after the coarse gas introduced from the coarse gas inlet 38 rises up the upflow-side water cooling wall 35a, the top of the cooler body Return near the descending duct 35
The gas is discharged from the crude gas discharge port 39 by descending the b.

The evaporating tube 33 as a heat transfer tube for recovering the gasification heat of the crude gas by heat transfer is provided on the upflow side water cooling wall 35a.
A economizer 34 is provided as shown. The width of the downflow duct 35b is relatively small because the width of the cooler body needs to be as small as possible.

As shown in FIG. 4, a gas purification facility 41 is connected downstream of the convection type crude gas cooler 27 (or 37), and a combined power generation facility 4 is located downstream of the gas purification facility 41.
2 are provided. Further, an air separation facility 43 for separating oxygen from air is provided by a coal gasification facility 40 and a combined power generation facility 42.
Is provided as shown in the figure.

[0010] In the case of a wet type, the gas purifying equipment 41 includes, for example, a filter 17 and a saturator 1 as shown in FIG.
8, a heat exchanger 19 and a desulfurization tower 12. The filter 17 is connected to the downstream side of the convective crude gas cooler 27, and the crude gas generated in the gasifier 5 After being introduced into the exchanger 19 and the desulfurization tower 12,
It is configured to be sent to the gas turbine 8 (see below) of the combined cycle power plant 42 via the saturator 18.
The gas purification equipment 41 may be of a dry type provided with a dry desulfurization tower, a regeneration tower, a filter (all not shown), and the like.

The combined power generation facility 42 includes the gas turbine 8 (including the combustor 8a and the compressor 29), the steam turbine 9, the exhaust heat recovery boiler 31, and the like. The gas turbine 8 is connected to the downstream side of the saturator 18 as described above, and the exhaust heat recovery boiler 31 and the steam turbine 9 are installed downstream of the gas turbine 8.
The exhaust heat from the exhaust gas is recovered by an exhaust heat recovery boiler 31 to drive the steam turbine 9.

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

The air separation equipment 43 is an air separator (rectification tower) 3 for separating high-purity oxygen from air by a cryogenic method or the like.
The air separator 38 is connected to the downstream side of the compressor 29 of the gas turbine 8 by the air introduction line 25 and is connected to the gasification furnace 5 via the oxygen supply line 13.
Connected upstream. Further, the air separator 38 is separated so that the remaining air component (mainly nitrogen) from which oxygen has been separated by the air separator 38 can be sent to the combustor 8a of the gas turbine 8 or the regeneration tower (in the case of a dry type) of the gas purification facility 41. May be connected to the combustor 8a or the regeneration tower.

The fuel such as coal is used in the bunker 1 of the gasification facility 40.
4. Coal slurried through the wet mill 15 and slurried (hereinafter referred to as slurry) is supplied to the slurry storage tank 1
It is introduced into the gasification furnace 5 through 6. When using a dry fuel, the dry fuel is introduced into the gasification furnace 5.

On the other hand, in the air separation equipment 43, high-purity oxygen is separated from the outside air and the air introduced from the compressor 29 of the gas turbine 8 through the air introduction line 25 by a method such as a deep cooling method. The separated high-purity oxygen is supplied to the gasification furnace 5 via the rectification column 38 and the oxygen supply line 13. The remaining air component (mainly nitrogen) from which oxygen has been separated is sent to the combustor 8a of the gas turbine 8 or the regeneration tower of the gas purification facility 41.

In the gasification furnace 5, high-purity oxygen is supplied from the air separator 38 of the air separation equipment 43 via the oxygen supply line 13 as described above, whereby the slurry (or dry fuel) is partially oxidized. And gasification to generate a crude gas (mainly H ₂ , CO, CO ₂ ).

The crude gas generated in the gasifier 5 is then supplied to the radiant crude gas cooler 6 and the convective crude gas cooler 27.
(Or 37) to the gas purification facility 41. At this time, the radiation type cooler 6 mainly emits radiation.
In the convection type crude gas cooler 27 (37), heat is recovered from the crude gas mainly by heat transfer.

That is, in the return flow type convection type coarse gas cooler 27 (see FIG. 3A), the coarse gas from the radiation type coarse gas cooler 6 is introduced through the coarse gas inlet 28 and the upward flow side. After ascending in the duct 25a, returning near the top and descending in the descending water cooling wall 25b, it is sent to the gas purification facility 41 through the crude gas discharge port 29. The crude gas comes into contact with the evaporator 23 and the economizer 24 sequentially when descending the descending water cooling wall 25b, whereby the heat of gasification of the crude gas is transferred to the evaporator 23 and economizer 24, The gas is cooled.

At this time, since the heat medium flows upward from below in the evaporator 23 and the economizer 24 (see FIG. 3A), the flow direction of the heat medium is opposite to the flow direction of the crude gas.
That is, the flow becomes countercurrent.

When the crude gas rises in the upflow duct 25a, the upflow-side duct 25a may be blocked by solids contained in the crude gas (see the part A in FIG. 3A).

On the other hand, in another type of return flow type convection type crude gas cooler 37 (see FIG. 3B), the crude gas from the radiation type crude gas cooler 6 is introduced through a crude gas inlet 38. Together with the ascending flow side water cooling wall 35a,
After returning near the top and descending in the downflow duct 35b, it is sent to the gas purification facility 41 via the crude gas outlet 39. The crude gas comes into contact with the evaporator 33 and the economizer 34 in order when ascending in the ascending water cooling wall 35a, whereby the heat of gasification of the crude gas is transferred to the evaporator 33 and economizer 34, The crude gas is cooled.

At this time, since the heat medium flows upward from below in the evaporator 33 and the economizer 34 (see FIG. 3B), the flow direction of the heat medium is the same as the flow direction of the crude gas in both.
That is, it becomes a parallel flow.

The crude gas discharged from the convection type crude gas cooler 27 (37) and introduced into the filter 17 of the gas purifying facility 41 is dedusted by the filter 17 and then passed through the heat exchanger 19 to the desulfurization tower. It is sent to 12 and desulfurized to become a purified gas. The purified gas discharged from the desulfurization tower 12 is
From the top through the saturator 18 to the gas turbine 8. When the gas purification equipment 41 is of a dry type, the crude gas is desulfurized in a dry desulfurization tower to become a purified gas, which is sent to the gas turbine 8 via a filter.

The purified gas sent to the gas turbine 8 is burned in a combustor 8a to generate power. At this time, the air (nitrogen) after oxygen separation from the air separator 38 is supplied to the combustor 8a.
To improve power generation efficiency.

The exhaust gas generated by the combustion in the combustor 8a of the gas turbine 8 is supplied to an exhaust heat recovery boiler 31 and a chimney 32.
Is released to the atmosphere through At this time, the heat recovery boiler 3
The steam turbine 9 further generates power by the exhaust heat recovered in 1.

[0026]

In the conventional return-flow convection-type crude gas cooler as described above,
Each of the two types had drawbacks.

That is, in a return-flow convection-type crude gas cooler in which both the evaporator and the economizer are installed on the water cooling wall on the downflow side, the duct on the upflow side is blocked by solids. There was a problem that it was easy to do.

In the case of this type of convective crude gas cooler, heat cannot be recovered by heat transfer at a portion near the inlet where the temperature is the highest in the convective coarse gas cooler. There was a problem of bad.

On the other hand, in a return flow type convective crude gas cooler of a type in which both the evaporator and the economizer are installed on the water cooling wall on the upflow side, the flow of the heat medium in the evaporator and the economizer is reduced. However, there is a problem that the heat transfer efficiency is poor because the gas flows in parallel with the gas flow, and the heat transfer area needs to be larger than that of the counter flow type.

In the case of this type of convective crude gas cooler, the outlet temperature of the heat medium in the economizer is reduced by the convective coarse gas cooling because the heat medium in the economizer flows in parallel with the gas flow. There is a problem that the temperature can be raised only to a temperature (to some extent) lower than the temperature of the crude gas at the outlet of the vessel, and that the temperature of the crude gas at the outlet of the convective crude gas cooler becomes relatively high.

Accordingly, an object of the present invention is to provide a return-flow convection-type crude gas cooler that can prevent blockage of a duct, increase the efficiency of heat recovery, and reduce the heat transfer area of a heat transfer tube.

[0032]

In order to achieve the above object, the invention of claim 1 is to provide a crude gas obtained by gasifying a fuel such as coal into contact with an evaporator and a economizer to reduce the heat of gasification by heat transfer. In the convection type crude gas cooler to be recovered, the cooler body is divided into a rising flow side water cooling wall part in which the crude gas is introduced and rising and a descending flow side water cooling wall part in which the crude gas descends and is discharged. An evaporator is provided on the upflow-side water cooling wall, and a economizer is provided on the downflow-side water cooling wall.

According to a second aspect of the present invention, the economizer and the evaporator pipe are arranged vertically so as to overlap in the cooler body as much as possible in the axial direction.

[0034]

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an integrated coal gasification combined cycle system (IGCC: Integr.) In which a fuel such as coal is gasified in a gasifier to generate a high-temperature crude gas which is used for power generation and the like.
ated Coal Gasification Combined Cycle, see Fig. 2)
The present invention relates to an improved return flow type convection type crude gas cooler.

FIG. 2 shows an integrated coal gasification combined cycle system 50 incorporating the return-flow convection crude gas cooler 7 of the present invention. Components other than the convective crude gas cooler 7 in the integrated coal gas combined cycle system 50 are the same as those of the conventional combined coal gasification combined cycle system 60 shown in FIG.

That is, the integrated coal gasification combined cycle system 50 shown in FIG. 2 is a combined coal gasification combined cycle system having a Texaco method coal gasification facility 51,
In this coal gasification facility 51, the crude gas cooler is composed of a radiation type crude gas cooler 6 and a convection type crude gas cooler 7, as shown in the figure. The crude gas cooler 6 and the convective crude gas cooler 7 are connected in order.

In the coal gasification facility 51 (Texaco type), the crude gas outlet 6 a of the radiant crude gas cooler 6 is installed below the radiant crude gas cooler 6. The return flow type convection type crude gas cooler 7 of the present invention is connected to the downstream side of the crude gas outlet 6a as shown.

FIG. 1 is an enlarged view of the return-flow convection-type crude gas cooler 7 of the present invention, together with a radiation-type crude gas cooler 6 and a gasification furnace 5 connected upstream thereof. It is an approximate side sectional view.

As shown in FIG. 1, the return-flow convective crude gas cooler 7 of the present invention has a cooler main body 2 as a pressure vessel. A coarse gas inlet 2a and a coarse gas outlet 2b are formed in the lower portion of the cooler main body 2, while an upflow side water cooling wall 5a and a downward flow side water cooling wall 5b are shown inside the cooler main body 2. The coarse gas introduced into the cooler main body 2 from the coarse gas inlet 2a rises up the upflow-side water cooling wall 5a and returns near the top of the cooler main body 2 to descend on the downflow side. It is configured to descend from the water cooling wall 5b and be discharged from the crude gas discharge port 2b.

The evaporator 3 as a heat transfer tube is installed in the upflow side water cooling wall 5a as shown in the figure, while the economizer 4 as the heat transfer tube is installed in the downflow side water cooling wall 5b. Connected as shown.

The portion for housing the evaporator 3 in the upflow-side water cooling wall 5a is configured to be thick enough to accommodate the evaporator 3, and similarly, the coal saving in the downflow-side water cooling wall 5b. The part accommodating the vessel 4 is configured to be thick enough to accommodate the economizer 4. On the other hand, the upper part of the ascending water cooling wall 5a that does not accommodate the heat transfer tubes and the lower part of the descending water cooling wall 5b are relatively thin, and the relatively thick and relatively thin parts of each of the water cooling walls 5a and 5b are vertically formed. In the direction (Fig. 1
), So that the entire cooler main body 2 is made as thin as possible.

At the downstream side of the convection type crude gas cooler 7, FIG.
, A gas purification facility 41 is connected, and a combined power generation facility 42 is provided downstream of the gas purification facility 41. Further, the air separation equipment 43 for separating oxygen from air is
It is connected to the coal gasification facility 51 and the combined cycle power generation facility 42 and provided as shown.

In the case of a wet type, the gas purifying equipment 41 includes, for example, a filter 17 and a saturator 1 as shown in FIG.
8, a heat exchanger 19 and a desulfurization tower 12, a filter 17 is connected downstream of the convective crude gas cooler 7, and the crude gas generated in the gasifier 5
After being introduced into the heat exchanger 19 and the desulfurization tower 12 from the gas turbine 7, the gas is sent to the gas turbine 8 (see below) of the combined cycle power plant 42 via the saturator 18.
The gas purification equipment 41 may be of a dry type provided with a dry desulfurization tower, a regeneration tower, a filter (all not shown), and the like.

The combined power generation facility 42 includes the gas turbine 8 (including the combustor 8a and the compressor 29), the steam turbine 9, the exhaust heat recovery boiler 31, and the like. The gas turbine 8 is connected to the downstream side of the saturator 18 as described above, and the exhaust heat recovery boiler 31 and the steam turbine 9 are installed downstream of the gas turbine 8.
The exhaust heat from the exhaust gas 8 is recovered by an exhaust heat recovery boiler 31 to drive the steam turbine 9.

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

The air separation equipment 43 has an air separator 38 for separating high-purity oxygen from air by a cryogenic method or the like.
The air separator 38 is connected to the downstream side of the compressor 29 of the gas turbine 8 by the air introduction line 25 and is connected to the upstream side of the gasification furnace 5 via the oxygen supply line 13. The remaining air component (mainly nitrogen) from which oxygen has been separated by the air separator 38 is converted into a combustor 8 a of the gas turbine 8.
Alternatively, the air separator 38 may be connected to the combustor 8a or the regeneration tower so that the air can be sent to the regeneration tower (in the case of a dry type) of the gas purification facility 41.

The fuel of the coal tower is the bunker 1 of the gasification facility 51.
4. Coal slurried through the wet mill 15 and slurried (hereinafter referred to as slurry) is supplied to the slurry storage tank 1
It is introduced into the gasification furnace 5 through 6. When using a dry fuel, the dry fuel is introduced into the gasification furnace 5.

On the other hand, in the air separation equipment 43, high-purity oxygen is separated from the outside air and the air introduced from the compressor 29 of the gas turbine 8 through the air introduction line 25 by a method such as a deep cooling method. The separated high-purity oxygen is supplied to the gasification furnace 5 via the oxygen supply line 13. The remaining air components (mainly nitrogen) from which oxygen has been separated
Combustor 8a of gas turbine 8 or gas purification facility 41
Sent to the regeneration tower.

In the gasification furnace 5, high-purity oxygen is supplied from the air separator 38 of the air separation equipment 43 via the oxygen supply line 13 as described above, whereby the slurry (or dry fuel) is partially oxidized. As a result, crude gas (mainly H ₂ , CO, CO ₂ ) is generated.

The crude gas generated in the gasification furnace 5 is then sent to the gas purification facility 41 via the radiant crude gas cooler 6 and the convective crude gas cooler 7 of the present invention. At this time, heat is recovered from the crude gas mainly by radiation in the radiation type cooler 6 and mainly by heat transfer in the convective coarse gas cooler 7.

That is, in the return flow type convection type crude gas cooler 7 of the present invention, the crude gas from the radiation type crude gas cooler 6 passes through the crude gas inlet 2a of the cooler main body 2 (see FIG. 1). After being introduced and rising inside the rising water cooling wall 5a, returning near the top and descending inside the falling water cooling wall 5b, it is sent to the gas purification facility 41 via the crude gas outlet 2b. The crude gas comes into contact with the evaporator 3 when ascending in the ascending flow side water cooling wall 5a, and then descends as the descending flow side water cooling wall 5b.
When descending inside, it comes into contact with the economizer 4, whereby the heat of gasification of the crude gas is transferred to the evaporator 3 and the economizer 4, thereby cooling the crude gas.

At this time, in the evaporator 3, the heat medium flows upward from below (ie, in parallel with the crude gas).
Is installed near the coarse gas inlet 2a (the highest temperature portion in the convection type coarse gas cooler 7) as described above, so that high heat recovery efficiency can be achieved. In addition, since the flow rate of the crude gas is slowed down in the evaporator 3 and the solid content is easily dropped, the solid portion is less likely to be clogged in the narrow portion of the upflow side water cooling wall 5a. In other words, the above-mentioned disadvantages of the conventional convective crude gas cooler 27 are almost overcome.

On the other hand, in the economizer 4, the flow direction of the heat medium is opposite to the flow direction of the crude gas, that is, the flow direction is opposite, so that the efficiency of conductivity is good. Therefore, the heat transfer area of the economizer 4 is relatively small. it can. In addition, because of the counter flow, the outlet temperature of the heat medium in the economizer 4 can be relatively high, and the crude gas temperature at the convection type coarse gas cooler outlet can be relatively low. To achieve heat recovery. That is, the above-described disadvantage of the convective crude gas cooler 37 is almost overcome.

The gasified gas discharged from the convective crude gas cooler 7 and introduced into the filter 17 of the gas purification facility 41 is subjected to dust removal by the filter 17 and then to the desulfurization tower 12 via the heat exchanger 19. It is sent and desulfurized to become a purified gas. The purified gas discharged from the desulfurization tower 12 is sent from the top of the desulfurization tower 12 to the gas turbine 8 via the saturator 18. When the gas purification equipment 41 is of a dry type, the combustion gas is desulfurized in a dry desulfurization tower to become a purified gas, which is sent to the gas turbine 8 via a filter.

The purified gas sent to the gas turbine 8 is burned in a combustor 8a to generate power. At this time, the air (nitrogen) after oxygen separation from the air separator 38 is supplied to the combustor 8a.
To improve power generation efficiency.

The exhaust gas generated by the combustion in the combustor 8 a of the gas turbine 8 is supplied to an exhaust heat recovery boiler 31 and a chimney 32.
Is released to the atmosphere through At this time, the heat recovery boiler 3
The steam turbine 9 further generates power by the exhaust heat recovered in 1.

In summary, according to the present invention, the flow rate of the crude gas is reduced by installing an evaporator below the rising water cooling wall (near the gas inlet) inside the return-flow convective crude gas cooler. Is slowed down in the evaporator, so that the solid content easily falls, and therefore, it is possible to prevent the upflow side water cooling wall from being blocked. Further, the heat recovery by the evaporator can be effectively performed in the highest temperature portion (near the gas inlet) in the convective crude gas cooler.

By installing the economizer above the descending water cooling wall inside the return-flow convection-type crude gas cooler, the flow direction of the heat medium in the economizer is the same as that of the coarse gas. On the contrary, the flow efficiency is improved due to the counter flow, and the heat transfer area of the economizer can be relatively small. In addition, because of the counterflow, the outlet temperature of the heat medium in the economizer can be relatively high, and the crude gas temperature at the convective crude gas cooler outlet can be relatively low. Heat recovery can be achieved.

That is, according to the present invention, it is possible to prevent the water cooling wall of the convection type coarse gas cooling from being clogged, to recover heat with high efficiency in both the evaporator and the economizer, and to further reduce the heat transfer of the economizer. The area can be saved.

Further, the relatively thick portion and the relatively narrow portion of each of the upflow-side water cooling wall and the downflow-side water cooling wall are engaged with each other in the vertical direction, so that the entire cooler main body is almost the same as the conventional one. It can be made compact.

[0061]

As described above, according to the return flow type convection type crude gas cooler of the present invention, the following excellent effects can be obtained.

(1) By installing an evaporator below the upflow water cooling wall (near the gas inlet) inside the return-flow convection-type crude gas cooler, the flow rate of the crude gas is reduced in the evaporator. This makes it easier for the solids to fall, thereby preventing the upward cooling water cooling wall from being clogged. Also, heat recovery by evaporator,
This can be effectively performed at the hottest part (near the gas inlet) in the convection type coarse gas cooler.

(2) By installing the economizer above the downflow water cooling wall inside the return-flow convection-type crude gas cooler, the direction of flow of the heat medium in the economizer is reduced. Opposite to the flow direction, that is, counter flow, the conductivity efficiency is improved, so that the heat transfer area of the economizer can be relatively small.
In addition, because of the counterflow, the outlet temperature of the heat medium in the economizer can be relatively high, and the crude gas temperature at the convection type coarse gas cooler outlet can be relatively low, with higher efficiency than in the case of parallel flow. Heat recovery can be achieved.

(3) The relatively thick portion and the relatively thin portion of each of the upflow-side water-cooling wall and the downflow-side water-cooling wall are engaged with each other in the vertical direction, so that the entire cooler body is comparable to the conventional one. It can be made compact in size.

[Brief description of the drawings]

FIG. 1 is a schematic side sectional view of a return-flow type convective crude gas cooler of the present invention and a radiation type crude gas cooler attached thereto.

FIG. 2 is a schematic diagram of an integrated coal gasification combined cycle power plant including a return flow type convective crude gas cooler of the present invention.

FIG. 3A is a schematic side sectional view of a conventional return-flow convection-type crude gas cooler.

FIG. 3B is another schematic side sectional view of a conventional return-flow convection-type crude gas cooler.

FIG. 4 is a schematic view of a conventional integrated coal gasification combined cycle power plant including a return-flow convection crude gas cooler.

[Explanation of symbols]

 2 (convective type crude gas) cooler body 3 evaporator 4 economizer 5a ascending water cooling wall 5b descending water cooling wall 7 convective crude gas cooler

Claims (2)

[Claims] 1. A convection-type crude gas cooler in which a crude gas obtained by gasifying a fuel such as coal is brought into contact with an evaporator and a economizer to recover heat of gasification by heat transfer. The rising water flow cooling wall portion is divided into a rising flow water cooling wall portion and a descending flow water cooling wall portion from which the crude gas descends and is discharged. An evaporator is provided in the rising flow water cooling wall portion and the downflow water cooling wall portion is provided. A return-flow convection-type crude gas cooler characterized in that a part is provided with a economizer. 2. The return-flow convection-type crude gas cooler according to claim 1, wherein the economizer and the evaporator tube are arranged vertically so as to overlap in the axial direction of the cooler body as much as possible.