WO1997044412A1

WO1997044412A1 - Coal gasification apparatus, coal gasification method and integrated coal gasification combined cycle power generating system

Info

Publication number: WO1997044412A1
Application number: PCT/JP1997/001668
Authority: WO
Inventors: Atsushi Morihara; Syntaro Koyama; Yoshio Naganuma; Shinji Tanaka; Sadao Takahashi; Takanori Kudou; Eiji Kida; Yoshiki Noguchi
Original assignee: Hitachi, Ltd.; Babcock-Hitachi Kabushiki Kaisha
Priority date: 1996-05-20
Filing date: 1997-05-19
Publication date: 1997-11-27
Also published as: JP4150937B2; KR20000015802A; AU730980B2; CN1221446A; AU2790097A

Abstract

A coal gasification apparatus is constructed such that a gasification furnace and a heat recovery unit for recovering heat obtained by a coal gasifying reaction in the coal gasification furnace without imposing load on subsequent equipment are integrally provided in a single vessel. The heat recovery unit is provided immediately above the gasification furnace and composed of heating tubes extending perpendicularly to a generated gas flow, and the gasification furnace is composed of a lower furnace portion and an upper furnace portion. An upper stage nozzle is disposed in the upper furnace portion and a lower stage nozzle is disposed in the lower furnace portion. The lower furnace portion supplies coal and a large amount of oxidizer via the lower stage nozzle to provide a temperature sufficient to melt an ash content, and the upper furnace portion supplies coal and a small amount of oxidizer via the upper stage nozzle to provide a temperature insufficient to melt the ash content, whereby the deposition of the ash content on furnace walls and the heat recovery unit is prevented. Also, the heating tubes, which constitute the heat recovery unit, are composed of two stages, which are different in surface temperature from each other, whereby the generated gas can be efficiently decreased in temperature to ease influences on constituent materials of the subsequent equipment.

Description

Specification

Coal gasifier, coal gasification method and integrated coal gasification combined cycle system

The present invention relates to an integrated coal gasification combined cycle system that supplies fuel gasified using a coal gasifier to a gas turbine to generate power, and mainly relates to a coal gasifier and a coal gasification method. Background art

Currently, the most widely used method for generating electricity by extracting energy from coal is to burn coal, convert it into thermal energy, generate steam, and recover it.

In contrast, in coal gasification, coal is not directly burned, but is converted into flammable gas by a gasification reaction using an oxidizing agent, and is directly supplied to power generation equipment such as gas turbines and fuel cells to be converted into electric energy. It is a method to do. The heat generated in this process is supplied to a steam turbine, which converts it into electrical energy. This method is more efficient because the gas turbine and fuel cell are driven directly by coal gas, compared to the conventional method of generating electricity by generating steam by directly burning coal. Furthermore, power can be generated by using a steam turbine, which can further improve efficiency.

For the above reasons, the power generation system based on coal gasification is expected as a next-generation high-efficiency power generation system.

Coal gasification technology is a technology that generates flammable gas composed of hydrogen, carbon monoxide, methane, carbon dioxide, steam, etc. by bringing coal into contact with oxidizing agents such as oxygen and steam at high temperature. It is.

As a coal gasifier that realizes this coal gasification, there is a gas bed (spouted bed) type gasifier. The gas-bed type is a device in which coal is pulverized into fine particles of about 10 microns to improve the contact efficiency with gas. Since the reaction is fast, the temperature in the gasification furnace of the apparatus becomes high and the reaction is completed quickly.

Furthermore, since the inside of the gasification furnace is at a high temperature (140 ° C to 180 ° C), it is possible to melt ash contained in coal. When the ash is melted, the contained harmful metals are contained in the molten ash, so it is also environmentally friendly. Therefore, a gas-bed gasifier is a coal gasifier with high efficiency and excellent environmental friendliness.

However, since the coal is reacted at a high temperature (140 ° C to 180 ° C), the generated gas is also hot. The generated gas contains unreacted carbon remaining after the coal has not completed the reaction, ash contained in the coal, corrosive hydrogen sulfide, and ammonia. If the temperature is higher than 150 ° C, This measure is necessary because the ash in the coal also becomes molten (the molten ash is called slag) and adheres to various equipment.

In order to supply the high-temperature product gas to the gas turbine, it is necessary to cool it to about 400 ° C or less with the current gas turbine constituent materials. On the other hand, there has been proposed a method for cooling a high-temperature product gas. There are two types of cooling systems: one that removes radiant heat from the heat transfer surface and one that uses heat exchange on the heat transfer surface due to convection of the generated gas.

In Japanese Unexamined Patent Publication (Kokai) No. Sho 61-222,093, a heat exchanger is provided directly connected to a gasification furnace (however, it is not provided in the same vessel). However, in order to avoid the slag scattered from the gasifier from adhering to the heat exchanger, the heat exchanger was not installed so as to block the gas flow, but was arranged so as to surround the gas flow. are doing. That is, a heat exchanger is installed in parallel with the gas flow. A heat exchanger is placed at a high density where the slag cools and solidifies to block the gas flow.

In the method in which the heat exchanger is arranged so as to surround the gas flow, heat can be recovered without greatly disturbing the gas flow. In particular, even if suspended matter such as slag exists in the generated gas, there is little obstacle due to it. However, since the gas flow is arranged so as to surround the gas flow, the amount of heat transfer per volume of the heat exchange part of the heat exchanger becomes small, and there is a problem that the heat exchanger itself becomes large. Increasing the size of the heat exchanger will increase the cost of the entire system.

In addition, because of the large size, it is necessary to provide multiple heat exchange units. Connect these Since the temperature of the connecting part also becomes high, it is difficult to select the material and design the structure. In particular, when the gasifier flows gas from bottom to top, the heat transfer section will flow from top to bottom through the connecting pipe. In this case, the scattered fine particles stay in the lower part of the heat transfer section, which is a problem for the device.

Japanese Patent Application Laid-Open No. 7-97579 discloses a method of providing a convection heat transfer surface for the purpose of recovering heat not only by radiation but also by heat transfer. In this method, the heat transfer tubes can be packed in a large amount, so that the apparatus can be downsized, which is advantageous. However, there is a problem that the slag in the gas flow adheres to the convection heat transfer surface, which may cause a blockage of the gas flow path or a local high temperature state.

There is also a method of cooling by mixing a cooling gas into the generated gas. In this method, a heat exchanger is not required if the cooling gas can be mixed well. However, it is necessary to mix a large amount of cooling gas, which increases the total amount of gas, so that the amount of gas handled by subsequent equipment also increases, and the equipment becomes larger accordingly.

In addition, the subsequent equipment in the above includes a dust removal device, a desulfurization device, and the like.

There is also a method in which coal is mixed with the generated gas and heat is recovered by endothermic reaction. This is effective in improving gasification efficiency because the ripeness is recovered by the endothermic reaction.

However, special equipment is required for the separation and recovery of unreacted products in the product gas. Specifically, it is a cyclone or a filter. Separation of such unreacted products must be carried out at high temperatures, and as a result Installation becomes complicated.

In particular, when the purpose is power generation, the response at the separation part becomes slow, and there is a problem in following the gas supply to the load fluctuation.

An object of the present invention is to provide a coal gasification apparatus and a coal gasification method capable of recovering heat obtained by a gasification reaction of coal at a low cost with a reduced burden on subsequent equipment.

It also aims to provide an integrated coal gasification combined cycle system using the above coal gasifier. Disclosure of the invention

The gist of the present invention that achieves the above object is as follows.

In a coal gasifier having a coal gasification reaction section and a heat recovery section for recovering heat of the reaction section, the heat recovery section is directly connected to a stage subsequent to the gasification reaction section, and is provided with power, radiation, and radiation. And a heat transfer tube that transfers heat by convection. The heat transfer tube is provided substantially orthogonal to the gas flow, and the heat recovery unit and the gasification reaction unit are provided in one vessel. A coal gasifier.

The gasification reaction section is in a coal gasifier having an upper reaction area and a lower reaction area.

Further, a heat recovery section provided directly after the gasification reaction section is provided with a first heat recovery section, and a surface of a first heat recovery section provided downstream of the first heat recovery section. To a coal gasifier consisting of a second heat recovery unit with a low temperature surface is there.

Here, the first heat recovery section cools the generated gas temperature from about 140 CTC to about 90 CTC, and the second heat recovery section converts the 900 ° C gas to about 400 ° C. It is to cool down.

Further, there is provided a coal gasifier having a carbon supply means between the gasification reaction section and the heat recovery section, which adjusts the ratio of carbon and ash in the produced gas by supplying carbon.

Further, in a coal gasification method using a coal gasification apparatus in which a reaction section for gasifying coal and a heat recovery section for recovering heat of the reaction section are provided in one vessel,

The heat recovery unit is provided directly after the gasification reaction unit, and is composed of a heat transfer tube that transfers heat by radiation and convection. The heat transfer tube is provided substantially orthogonal to the gas flow. And

The reaction section has an upper reaction area and a lower reaction area. The upper reaction area is supplied with an amount of oxidizing agent at a temperature at which the ash contained in the coal does not melt, and the lower reaction area has an upper and lower reaction area. Oxidizer is supplied by subtracting the oxidizer supplied to the upper part from the oxidizer required to convert all supplied coal to carbon monoxide and hydrogen, and the radiation provided directly to the reaction section And a coal gasification method in which heat of reaction is recovered by a heat recovery unit that transfers heat by convection. Furthermore, the coal and the oxidizing agent are reacted in the gasification reaction section configured so that the cross-sectional area of the upper end and the lower end is reduced, and the ash content is melted and discharged from the lower end of the gasification reaction section. Combustible gas generated from the upper end This is a coal gasification method in which cooling is performed by a heat recovery unit directly connected to the gasification system. An oxidizing agent is supplied to the lower part of the gasification reaction unit in such a way that the ash of the supplied coal can be melted. The upper part of the gasification reaction section is supplied with an oxidizing agent in an amount such that the ash content in the coal does not melt, and further, carbon is supplied from carbon supply means provided between the gasification reaction section and the heat recovery section. This is a coal gasification method that controls the amount of carbon supplied so that ash does not adhere to the heat recovery section by supplying it. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a schematic diagram showing a state of a gasification reaction of a gasifier of the present invention. FIG. 2 is a graph showing the relationship between the ratio of carbon and ash in the ash of a coal gasifier and the adhesion of the ash depending on the temperature. FIG. 3 is a schematic longitudinal sectional view of the coal gasifier of Example 1. FIG. 4 is a schematic cross-sectional view of the coal gasifier of the first embodiment. FIG. 5 is a configuration diagram of an integrated coal gasification combined cycle system using the coal gasifier of the first embodiment. FIG. 6 is a graph comparing the operating temperatures of the coal gasifier of the present embodiment and the conventional example. FIG. 7 is a graph comparing the size of the coal gasifier of the present embodiment with that of the conventional example. FIG. 8 is a schematic vertical sectional view of the coal gasifier of the second embodiment. FIG. 9 is a schematic longitudinal sectional view of the coal gasifier of the third embodiment. BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be described in more detail with reference to the accompanying drawings. First, the main gasification reaction of coal can be expressed by equations (1) to (4). Coal → volatile matter (CH ₄ , CO, H ₂ etc.) + CH (C) ■ (1) CH (C) + H ₂ O → CO + H ₂ · (2) CH ( C) + CO ₂ → 2 CO (3)

(Coal, Chiya _{_{one) +0 2 → CO + C0 2}} ... (4) (1) to (3) is an endothermic reaction, (4) is an exothermic reaction. In general, at first, volatiles are generated by the reaction of (1), and at the same time as the generation of char, the volatiles burn and the temperature in the furnace increases. Further, (4) reaction with the reaction force stiffness coal and oxygen, also the temperature in the furnace is CO, C0 ₂ is generated with increased.

H ₂ 0 and C0 ₂ produced in volatiles of combustion of H ₂ and CO (2), (3) reacts with unburned carbon (Chiya I) in a high temperature atmosphere as shown by the combustible gas Form.

In a gas-bed gasifier, the temperature of the coal is set to a temperature that is sufficient to melt the ash in the reaction stage, the ash is melted and taken out as a liquid slag, and the harmful metal is encapsulated by cooling it into a slag. Discharge.

The coal gasifier of the present invention is a gas-bed type two-stage gasifier, which divides the inside of the gasifier into upper and lower parts, and supplies coal and a small amount of oxidizing agent from the upper part and coal and a large amount of oxidizing agent from the lower part. As a result, the temperature in the lower stage is sufficient for the ash in the coal to melt.

In addition, by setting the temperature at which ash is not melted in the upper stage, sticking of ash to the furnace wall due to the gasification reaction is suppressed. This allows the handling of ash And high gasification efficiency can be achieved at the same time.

FIG. 1 schematically shows a gasification reaction state of the gasification apparatus of the present invention.

Coal supplied from the lower parner reacts with a large amount of oxidizing agent to generate product gas and molten ash (slag). On the other hand, coal supplied from the upper parner produces fine char due to the endothermic reaction.

The char generated in the upper part of the gasification furnace adheres as powder to the surface of the slag generated in the lower part of the gasification furnace, and has an action and an effect of suppressing adhesion to the furnace wall and the heat recovery part. As described above, the coal gasifier of the present invention can prevent the slag generated in the gasifier from adhering to the heat recovery unit by reducing the slag generated in the gasifier. And the heat recovery section (heat transfer tube) can be integrated.

Figure 2 shows the relationship between the ratio of carbon and ash in coal ash (char) and the adhesion of ash to temperature. The horizontal axis shows the carbon concentration of the ash, and the vertical axis shows the temperature.

The ash adhesion is high in the shaded area. In other words, it indicates that in the region where the temperature is high and the carbon concentration in the ash is low, the ash in the generated gas tends to adhere to the heat recovery section (heat transfer tube). On the other hand, when the temperature is low (below 90 CTC) or when the carbon concentration in the ash is high (over 10%), the adhesion of the ash in the produced gas is low. That is, it shows that it is hard to adhere to the heat transfer tube. From the above, by increasing the ratio of carbon to ash in the generated gas, it is possible to suppress ash from adhering to the heat recovery section such as a heat transfer tube. This This makes it possible to provide a compact coal gasifier in which a heat recovery section for recovering the heat generated in the reaction is integrally disposed immediately after the gasifier.

Further, according to the coal gasifier of the present invention, supply of a cooling gas or the like is not required, or even if it is supplied, the amount thereof can be reduced. Therefore, subsequent equipment can be downsized.

The heat recovery unit provided directly after the gasification reaction unit of the present invention includes:

It is preferable that the first heat recovery section and the second heat recovery section having a lower temperature than the surface of the first heat recovery section are provided at a subsequent stage of the first heat recovery section. The first and second heat recovery sections are installed in the gas flow so as to be orthogonal to the gas flow direction. In the first heat recovery section, the temperature of the generated gas is cooled to 140 (TC is reduced to 900 ° C. Here, high-temperature steam can be obtained. On the other hand, in the second heat recovery section, the generated heat is generated. Gas temperature 900 ° C is cooled to 40 (TC.

The reason for this configuration is to increase the heat transfer efficiency and to make more effective use of the volume. The heat recovery section is a two-stage heat recovery section with different temperatures in order to recover the heat of the generated gas most efficiently. As a specific example of the shape of the mature recovery section, a spiral or zigzag metallic heat transfer tube is preferable. The formation density can be set arbitrarily according to the capacity of the gasification furnace.

High-temperature water (or high-temperature steam) is supplied to the heat transfer tube serving as the first heat recovery unit, and low-temperature water (or high-temperature water) is supplied to the heat transfer tube serving as the second heat recovery unit. Through low-temperature steam) to recover heat from the gasification reaction. That is, the first heat recovery unit is used as an evaporator or a super heater, and the second heat recovery unit is used as an evaporator or a economizer.

Next, the present invention will be described based on more specific examples.

(Example 1)

FIG. 3 shows a schematic longitudinal sectional view of the coal gasifier of the present invention. The coal gasifier has a gasification reaction section surrounded by the vessel 51 and a heat recovery section arranged directly connected to the subsequent stage. The gasification reaction section (hereinafter referred to as gasification furnace) consists of a furnace upper part 28 and a furnace lower part 29. An upper nozzle 31 is installed in the furnace upper part 28, and a lower nozzle 32 is installed in the furnace lower part 29.

At the upper end of the gasifier 25, a recycle nozzle 6 is provided. At the lower end of the gasifier 25, a slag tap 26 is provided, and the diameter of the gasifier 25 is reduced at these points. A slag water cooling tank 30 is provided below the gasification furnace 25. Further, a high-temperature heat recovery section 23 and a low-temperature heat recovery section 22 are provided immediately above the gasification furnace 25. The inner wall of the gasifier 25 is protected by a water-cooled wall 24 cooled by water and a refractory material 60 on its surface.

Fig. 4 shows a cross-sectional view of the gasification furnace. (A) Figure shows the part where the recycle nozzle 6 for supplying the recycle gas is provided, (b) shows the part where the upper nozzle 31 is provided, and (c) shows the part where the lower nozzle 32 is provided. It is a cross-sectional view of each of the parts.

The direction of each nozzle is oriented so that it is supplied to the center in the order of (a), (b), and (c) as shown in the swirl diameters 41 to 43 of the gas flow. In this way, the furnace wall can be covered in the order of the recycle gas, the upper product gas, and the lower product gas from the side closer to the furnace wall. That is, the lower temperature gas is made to be on the furnace wall side to protect the furnace wall 44.

From the upper nozzle 31, the coal 9 and the oxygen 8 are supplied at a predetermined ratio so that the temperature of the coal 9 and the oxygen 8 does not melt the ash in the coal. From the lower nozzle 32, both coal 9 and oxygen 8 are supplied at a predetermined ratio so as to reach a temperature at which ash is melted.

Here, an additive 11 made of limestone or the like for lowering the melting point of the ash or assisting a reaction such as desulfurization in a furnace may be supplied together with the coal. Further, steam 10 may be supplied as a furnace temperature control and an oxidizing agent. In addition, the recycled charcoal 13 recovered by the equipment (dust removal device) at the latter stage of the coal gasifier is supplied from below the gasifier 25. As a result, a reaction zone having a temperature lower than the melting point of the ash is formed in the furnace upper part 28. Further, a reaction region having a temperature higher than the melting point of the ash is formed in the lower furnace part 29, and a molten slag is formed between this region and the furnace wall. In addition, the above-mentioned recycle channel is mainly composed of unburned carbon and ash.

Next, Table 1 shows an example of the operating conditions of the above coal gasifier.

Table 1

Under these operating conditions, coal was supplied in equal amounts to the upper part 28 and the lower part 29 of the furnace. Oxygen is supplied in sufficient quantity to gasify the supplied coal. The ratio of total oxygen and total coal under these operating conditions is 0.8 by weight. In the upper part 28 of the furnace, the ratio of oxygen-free coal was set to 0.58 in order to supply oxygen in an amount that would not melt the ash in the coal. The amount of oxygen supplied to the lower part 29 of the furnace is supplied by subtracting the amount of oxygen supplied to the upper part of the furnace from the total amount of oxygen. Therefore, the ratio of oxygen coal in the lower part 29 of the furnace under the operating conditions is 1.02. The ratio of oxygen supplied together with the recycling channel is included in the total oxygen amount.

Under the above operating conditions, the temperature of the lower furnace part 29 is about 156 ° C., which is a temperature sufficient to melt the ash in the coal.

On the other hand, since the upper part 28 of the furnace is in a temperature range (900 to 140 ° C) lower than the melting point of ash, char is generated, and the slag generated in the lower part of the furnace is Adheres as powder on the surface of. As a result, even if the slag reaches the heat recovery sections 23 and 22 (heat transfer tubes) installed above the gasifier 25, it does not adhere to them. Therefore, it is possible to improve a decrease in heat transfer due to slag adhering to the surface of the heat transfer tube.

Further, also on the surface of the heat transfer tube, the carbon powder helps to destroy the boundary layer of the attached matter, so that the heat transfer coefficient of the heat transfer tube can be favorably maintained. The product gas containing slag with low adhesion wrapped in carbon powder is discharged from the outlet throttle section 27 of the gasifier 25 and cooled by the high-temperature heat recovery section 23 cooled first by high-temperature water 5. Heat is recovered as high-pressure steam 4. Next, it is further cooled by the low-temperature heat exchanger 22 cooled by the low-temperature water 3 and recovered as low-pressure steam 2. The product gas cooled as described above is sent to equipment provided downstream of the gasifier outlet 21.

In this embodiment, since the heat recovery unit and the gasifier 25 are integrated in the vessel 51, the entire gasifier can be reduced in size. Next, Fig. 5 shows the configuration of an integrated coal gasification combined cycle system using the coal gasifier of this embodiment.

This power generation system is composed of a coal gasifier, a gas purifier, a combined gas turbine / steam turbine generator, and the like.

Oxygen is supplied to the coal gasifier 82 by the oxygen generator 81. Coal is atomized and supplied from a coal hopper 80, pressurized with excess nitrogen generated in an oxygen production unit 81, and compressed by an upper nozzle 31 and a lower nozzle 32 of a coal gasifier 82. Will be re-supplied. The amount of coal supplied to the upper nozzle 31 is adjusted by the upper coal supply controller 92. The amount of coal supplied to the lower nozzle 32 is similarly adjusted by the lower coal supply controller 93. The gasifier 25 in the coal gasifier 82 is recovered as low-pressure water vapor 2 by a heat recovery unit (22, 23 in Fig. 1) that absorbs heat by convection and radiation. Is done. Here, since the heat transfer tube is orthogonal to the gas flow, heat exchange with the high-temperature gas occurs sufficiently, and the generated gas is cooled from a high temperature of 140 ° C or more to 400 ° C. .

Dust is removed from the generated gas by a dedusting device 83 composed of a cyclone, a high-temperature bag filter, or a high-temperature electrostatic precipitator. Further, sulfides such as H ₂ S and COS are removed by a desulfurization device 84 such as a wet desulfurization device that desulfurizes by absorbing liquid or a dry desulfurization device that desulfurizes by using a solid desulfurizing agent.

The resulting gas, from which dust and sulfur compounds have been removed and purified, is supplied to the combustor of gas turbine 85, which directly burns and drives the turbine and converts it into electric power. Is done. The gas turbine re-loiling temperature must be about 40 (TC or less) for reasons such as valve reliability. In the gas turbine 85, the air 61 is compressed to form compressed air. The gas is supplied to the oxygen production unit 81 or the coal gasification unit 82.

A part of the purified gas is pressurized by a compressor 101 and supplied to a coal gasifier 82 from a recycling nozzle 6. This is used to cool the gas produced in the gasifier 25.

The high-temperature exhaust gas from the gas turbine 85 is recovered as steam by the heat recovery poir 86. The recovered steam is supplied to the steam turbine 87 and converted into electric power.

Steam generated by the heat exchanger directly connected to the gasifier is also supplied to the steam turbine to generate power.

As described above, in the coal gasifier of the present invention, since the generated gas is efficiently cooled by the heat recovery unit provided directly, the supply amount of the cooling gas can be reduced. . Because of this, the amount of gas other than coal gas passing through the dust removal device 83 and the desulfurization device 84 is small, so that these gas purification devices can be downsized, and the integrated coal gasification combined cycle system can be integrated. It can be downsized.

Next, FIG. 6 compares the operating temperatures of the coal gasifier of the present embodiment and the conventional example.

In the conventional method, the gas temperature at the outlet of the gasifier is as high as about 150 ° C. Therefore, before the product gas reaches the heat exchanger, reduce the temperature to 900 ° C or less. Need to use large amounts of cooling gas. This temperature is shown in FIG.

On the other hand, according to the gasification method of the two-stage reaction of the present embodiment, the temperature force at the outlet 27 of the gasification furnace 25 is already as low as 40 CTC, and the ratio of carbon to ash in the generated gas Is large, the adhesion to the heat recovery section and the like is suppressed. The temperature entering the heat recovery section may be about 1200 ° C. Therefore, even when the cooling gas is supplied, the amount may be small.

FIG. 7 is a graph comparing the size of the gasifier of the present embodiment with that of the conventional example (including the heat recovery unit).

Conventional example 1 is a case where a radiation type heat recovery unit is used in a single-stage reaction type gasification furnace, and since the radiation surface per unit cross-sectional area cannot be increased, the furnace becomes large.

Conventional example 2 is a two-stage reaction type gasification furnace, in which the temperature at the outlet of the furnace can be lowered, so that the heat recovery unit can be made relatively small.

In the coal gasifier of this embodiment in which the heat recovery section is formed integrally with the gasification furnace, the heat recovery section can use a convection heat transfer section in addition to the radiant heat transfer section, making the gasification apparatus extremely compact. Can be

(Example 2)

This embodiment will be described with reference to FIG. A gasification zone is formed in the upper and lower stages, only coal is supplied in the upper reaction zone, all ash formed in the upper reaction zone is discharged outside the furnace, and unreacted carbon catalyst collected outside the system is collected. Is collected and supplied to the lower reaction zone as a recycling channel 13. In the lower reaction zone 29, oxygen 8 and coal 9 are supplied, and combustion reaction mainly occurs. reaction A gasification reaction mainly occurs in the upper reaction zone 28 formed in the upper part of the furnace 25.

The specific effect of the present embodiment is that the combustible gas formed in the upper reaction zone 28 is discharged without any contact with the oxidizing agent, so that the calorific value of the generated gas can be increased.

(Example 3)

Embodiment 3 will be described with reference to FIG. This embodiment is a one-stage reaction type coal gasifier. Reaction zone 33 is supplied with coal 9 and oxygen 8. Reduces the ratio of oxygen to coal, forms unreacted carbon, and suppresses adhesion to the heat recovery section. Unreacted carbon is collected by a dust removal device at the subsequent stage and supplied as a recycling channel.

In addition, since the supply position of the recycling channel 13 is located immediately below the heat recovery section 23, the adhesion of slag is suppressed by this channel. The specific effect of this embodiment is that the reaction region (33) is made into a --- stage, so that its structure can be simplified and the cost of the apparatus can be reduced. Industrial applicability

ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of unburned carbon or gas supply to a gasifier suppresses adhesion of ash slag, and integration of a heat recovery part and a gasifier can be realized. Thus, the size of the coal gasifier can be reduced.

In addition, since there is no need to supply a cooling gas, Gas is not mixed, simplifying the entire system,

Claims

The scope of the claims

1. In a coal gasifier having a coal gasification reaction section and a heat recovery section for recovering heat of the reaction section, the heat recovery section is provided directly connected to a stage subsequent to the gasification reaction section, and is radiated. And a heat transfer tube that transfers heat by convection. The heat transfer tube is provided substantially orthogonal to the gas flow, and the heat recovery unit and the gasification reaction unit are provided in one vessel. A coal gasifier characterized by the following.

2. The coal gasification reaction section has an upper reaction area and a lower reaction area, and a coal supply means is provided in each of the two reaction areas, and a heat recovery section is provided directly connected to the upper reaction area. The coal gasifier according to claim 1.

3. The coal gasifier according to claim 1, wherein the gasification reaction section is constituted by a water-cooled wall lined with a refractory material, and the heat recovery section is formed by a water-cooled tube.

4. The heat recovery unit directly connected to the subsequent stage of the gasification reaction unit includes a first heat recovery unit and a surface of the first heat recovery unit provided downstream of the first heat recovery unit. The coal gasifier according to any one of claims 1 to 3, further comprising a second heat recovery unit having a low-temperature surface.

5. A carbon supply means between the gasification reaction section and the heat recovery section, the carbon supply means for adjusting the ratio of carbon and ash in the product gas by supplying carbon. 5. The coal gasifier according to any one of items 4.

6. In a coal gasification method using a coal gasifier in which a reaction section for gasifying coal and a heat recovery section for recovering heat of the reaction section are provided in one vessel,

The heat recovery unit is provided directly after the gasification reaction unit, and is composed of a heat transfer tube that transfers heat by radiation and convection. The heat transfer tube is provided substantially orthogonal to the gas flow. Have been

The reaction section has an upper reaction area and a lower reaction area. The upper reaction area is supplied with an amount of oxidizing agent at a temperature at which the ash contained in the coal does not melt, and the lower reaction area has an upper and lower reaction area. Oxidizer is supplied by subtracting the oxidizer supplied to the upper part from the oxidizer required to convert all supplied coal to carbon monoxide and hydrogen, and the radiation provided directly to the reaction section A method for converting coal into gas, comprising recovering reaction heat by a heat recovery unit that transfers heat by convection.

7. Coal reacts with the oxidizing agent in the gasification reaction section configured to reduce the cross-sectional area of the upper and lower ends, melts and discharges the ash from the lower end of the gasification reaction section, and discharges the ash from the upper end of the gasification reaction section. A coal gasification method in which regenerated combustible gas is cooled by a heat recovery unit provided directly above the combustible gas,

The heat recovery unit includes a heat transfer tube that transfers heat to radiation and convection, and the heat transfer tube is provided substantially orthogonal to the gas flow.

The lower part of the gasification reaction section is supplied with an amount of oxidizing agent at a temperature capable of melting the ash of the supplied coal, and the upper part of the gasification reaction section is supplied with an amount of oxidant at a temperature at which the ash contained in the coal does not melt. Supplying an oxidizing agent, and further, A coal gasification method comprising supplying carbon from a carbon supply means provided between heat recovery sections to control the amount of carbon so that ash does not adhere to the heat recovery section.

8. The coal gas according to claim 6 or 7, wherein the ash containing carbon separated by passing the gasified coal gas through a dust remover is recycled and mixed into the gasification reaction section. Method.

9. A heat recovery section provided directly after the gasification reaction section is a first heat recovery section and a first heat recovery section provided after the first heat recovery section. The coal gasification method according to any one of claims 6 to 8, comprising a two-stage heat recovery unit with a second heat recovery unit having a low-temperature surface.

10. In a combined coal gasification power generation system including a coal gasification device, an oxygen production device, a gas purification device, and a gas turbine power generation device, the coal gasification device includes: a coal gasification reaction unit; A heat recovery unit that recovers heat of the reaction unit, wherein the heat recovery unit is provided directly connected to a subsequent stage of the gasification reaction unit, and includes a heat transfer tube that transfers heat by radiation and convection. Is provided substantially orthogonal to the gas flow, and the heat recovery section and the gasification reaction section are provided in a single vessel.

1 1. A heat recovery section provided directly after the gasification reaction section is a first heat recovery section and a surface of a first heat recovery section provided after the first heat recovery section. 10. The integrated coal gasification combined cycle system according to claim 10, further comprising: a second heat recovery unit having a low-temperature surface.

12. Claim 10 having a carbon supply means between the gasification reaction section and the heat recovery section, the carbon supply means for adjusting the ratio of carbon and ash in the product gas by supplying carbon. Or the integrated coal gasification combined cycle system according to paragraph 11.

13. The ash containing carbon in the coal gas separated by passing the gasified coal gas through a gas purifier is recycled and mixed into the gasification reaction section. 3. The integrated coal gasification combined cycle system according to any one of items 2.