JP2014077031A - System for gasifying carbon-based fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system for gasifying carbon-based fuel, in which the equipment cost and construction cost of a gasification furnace are reduced, the high-temperature waste water to be generated in the gasification furnace are utilized effectively and the waste heat thereof is also utilized.SOLUTION: The high-temperature water withdrawn from a slag cooling water storage part 12 of the bottom of the gasification furnace 3 for gasifying carbon-based fuel is supplied to the downstream side of the gasification furnace or the upstream side of a dust removal unit 8 through a water supply system c and is mixed with the generated gas to cool the generated gas. As a result, a heat recovery part 7 for recovering the heat of the generated gas is miniaturized or removed. Since the high-temperature water withdrawn from the slag cooling water storage part 12 is used, the high-temperature water is evaporated easily when mixed with the generated gas and the generated gas is cooled efficiently. Solids accompanied by the generated gas are recovered in the dust removal unit 8 and thrown again in the gasification furnace 3. Thereby, utilization of waste heat of high-temperature water, carbon loss and reduction of waste can be realized.

Description

  The present invention relates to a gasification system for a carbon-based fuel such as coal, and more particularly to a carbon-based fuel gasification system that achieves both wastewater and waste heat utilization and waste reduction.

  The product gas generated by gasifying carbon-based fuel such as coal reaches 1000 ° C. or more at the gasification furnace outlet. In order to purify the product gas by dedusting and removing impurities such as chlorine and sulfur, it is necessary to cool the product gas to less than 400 ° C. In the gasification system for power generation, heat recovery is performed when the product gas is cooled to increase energy efficiency.

  The product gas emitted from the gasification furnace is accompanied by a large amount of solid matter composed of unburned carbon and ash. For this reason, it is necessary to prevent the following two troubles in the process of cooling while recovering heat from the product gas.

  One of them is that it is necessary to prevent the molten ash from adhering to the heat transfer tube (slagging) in a high temperature atmosphere of 1000 ° C. or higher.

The other is that in the process of cooling the product gas to about 800 to 900 ° C., it is necessary to prevent the deposited alkali metal salt (Na ₂ SO ₄ or the like) from adhering to the heat transfer tube (fouling). It is.

  As a countermeasure for preventing the trouble described above, the product gas discharged from the gasifier is cooled in two stages. Here, the first heat recovery unit and the second heat recovery unit are called from the upstream (gasification furnace) side. In the first heat recovery section, the product gas is cooled to 800 to 900 ° C., and heat recovery is performed with a water-cooled wall. In the second heat recovery unit, the product gas is cooled to less than 400 ° C., and heat is recovered by heat transfer tubes installed in the heat recovery unit and on the wall surface.

  However, the heights of the first heat recovery unit and the second heat recovery unit have reached several times that of the gasification furnace, which has been a factor in increasing gasification system equipment and construction costs. In order to reduce such equipment and construction costs, for example, in Japanese Patent Laid-Open No. 9-194855, a part of the cleaning water for cleaning the generated gas in the purification process is sprayed into the heat recovery unit, and the heat recovery unit is downsized. A technique relating to a cooling system for the generated gas is disclosed.

  Japanese Patent Application Laid-Open No. 59-136389 discloses that a part of the cleaning water for cleaning the generated gas in the purification process is sprayed on the generated gas, and the cleaning water sprayed on the generated gas is submerged in the slag cooling water reservoir. A technology related to a cooling system that circulates is disclosed. In this cooling system, the molten slag accompanying the product gas can be removed in the slag cooling water storage unit, and a heat recovery unit for cooling the product gas can be eliminated.

JP-A-9-194855 JP 59-136389 A

  A large amount of molten slag heated to the melting point of coal ash (approximately 1200 to 1500 ° C. and different depending on the coal type) flows into the slag cooling water reservoir. The molten slag is quenched in the slag cooling water reservoir, and becomes amorphous (glassy) granular granulated slag. For this reason, the slag cooling water in the slag cooling water reservoir is heated by the heat from the molten slag.

  In order to prevent evaporation of the slag cooling water in the slag cooling water reservoir, the slag cooling water is circulated and cooled. This is to prevent a decrease in the amount of slag cooling water and a temperature decrease in the gasifier due to evaporation of the slag cooling water.

  The temperature of the slag cooling water heated in the slag cooling water storage part is several tens of degrees Celsius higher than normal temperature, even if it is less than 100 ° C. that does not boil even under normal pressure.

  In addition, the mass flow rate of slag cooling water that is circulated and cooled reaches about 0.5 to 2 times that of coal (varies depending on ash content, melting point, etc.) in the case of a coal gasifier. Therefore, in some cases, the sensible heat of the slag cooling water heated to a high temperature in the slag cooling water reservoir reaches about 1% of the calorific value of the coal charged into the gasification furnace.

  However, the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 9-194855 does not mention the use of exhaust heat from high-temperature water extracted from the slag cooling water reservoir.

  In the technique disclosed in JP-A-59-136389, a heat exchanger is installed in high-temperature water extracted from the slag cooling water reservoir, and the exhaust heat of the high-temperature water is used as a heat source for heating water at room temperature. ing. In this case, at the outlet of the heat exchanger, the high-temperature water extracted from the slag cooling water reservoir is higher than the normal temperature, so that the exhaust heat of the high-temperature water cannot be used efficiently.

  An object of the present invention is to efficiently reduce the generated gas taken out from the gasification furnace by efficiently using the exhaust heat of high-temperature water generated in the gasification system, and to reduce carbon loss and waste generated from the carbon-based fuel. An object is to provide a carbonized fuel gasification system.

  A gasification system for a carbon-based fuel according to the present invention includes a gasification furnace that gasifies solid carbon-based fuel to generate a product gas, and a fuel that conveys the solid carbon-based fuel from a coal hopper to the gasification furnace. The supply system and the gasification furnace take out the product gas generated by gasifying the carbon-based fuel from the upper side of the gasification furnace, convert the inorganic substance contained in the carbon-based fuel into molten slag, and lower the gasification furnace. And a dust removing unit that is installed on the downstream side of the gasification furnace and dedusts the product gas taken out from above the gasification furnace, and is dedusted by the dust removal part, and the product gas A char hopper that collects the char accompanied with the char, a char supply system that conveys the char collected by the char hopper to the gasification furnace from the char hopper, and the dust removing unit that is installed downstream of the dust removing unit. The product gas flowing down A high-temperature water having a washing tower to be purified, a slag cooling water storage section that is cooled by cooling water supplied from the outside with molten slag at the bottom of the gasification furnace, and heated by the molten slag in the slag cooling water storage section From the slag cooling water storage part to the downstream side of the gasification furnace or the upstream side of the dedusting part to dispose a water supply system for cooling the generated gas taken out from the gasification furnace. Features.

  According to the present invention, exhaust gas generated from a gasification furnace is cooled efficiently by using exhaust heat of high-temperature water generated in a gasification system, and carbon loss and waste generated from a carbon-based fuel are reduced. A carbonized fuel gasification system can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS The system diagram which shows the structure of the coal gasification combined cycle power plant provided with the gasification system of the carbonaceous fuel which is 1st Example of this invention. The system diagram which shows the structure of the coal gasification combined cycle power plant provided with the gasification system of the carbon-type fuel which is 2nd Example of this invention. The system diagram which shows the structure of the coal gasification combined cycle power plant provided with the gasification system of the carbonaceous fuel which is the 3rd example of the present invention. The system diagram which shows the structure of the coal gasification combined cycle power plant provided with the gasification system of the carbonaceous fuel which is the 4th example of the present invention. The system diagram which shows the structure of the coal gasification combined cycle power plant provided with the gasification system of the carbon-type fuel which is 5th Example of this invention.

  A carbon fuel gasification system according to an embodiment of the present invention will be described below with reference to the drawings.

  A coal gasification combined power plant equipped with a carbon-based fuel gasification system according to a first embodiment of the present invention will be described with reference to FIG.

  The carbonized fuel gasification system of this embodiment shown in FIG. 1 efficiently uses the sensible heat of high-temperature water generated in the cooling water reservoir of molten slag to produce a gas produced by gasifying the carbon-based fuel. It is the carbonization fuel gasification system which reduced the heat recovery part which cools.

  A carbonized fuel gasification system according to a first embodiment of the present invention will be described with reference to FIG. 1 by taking as an example a case where coal is used as fuel and a gas turbine and a steam turbine are driven by generated gas.

  FIG. 1 is a system diagram showing the configuration of a coal gasification combined power plant equipped with a carbon fuel gasification system according to a first embodiment of the present invention, and a coal hopper 2 for storing carbon fuel coal, From an air separator 4 that produces oxygen and nitrogen from the air, a fuel supply system a that conveys coal from the coal hopper 2 to the gasification furnace 3 by gas, and a coal and air separator 4 that is supplied through the fuel supply system a The gasification furnace 3 that combusts the oxygen of the supplied gasifying agent together to generate the product gas 5 and the downstream of the gasification furnace 3 are installed, and the product gas 5 discharged from the gasification furnace 3 is dedusted. In addition, a dedusting device 8 that recovers the char 9 contained in the product gas 5, a heat exchanger 10 and a venturi 11 that cools the product gas 5 after dedusting, a halogen-based substance contained in the product gas 5, , The fine that could not be collected by the dust removal device 8 A water scrubber 13 to remove the strike component, and each comprise a desulfurization apparatus 17 for removing sulfur product gas 5.

  Further, the char 9 collected by the dust removing device 8 is stored in the char hopper 25, transported by nitrogen separated from the air by the air separator 4 through the char supply system b, and re-entered into the gasification furnace 3.

  Further, the product gas 39 desulfurized by the desulfurization device 17 is supplied from the desulfurization device 17 to the product gas heat exchanger 10 and reheated, and then supplied to the gas turbine device as fuel.

  This gas turbine apparatus includes a compressor 24 that compresses air, a gas turbine combustor 18 that mixes and burns the product gas 39 supplied as fuel with the air compressed by the compressor 24 to generate high-temperature combustion gas, The turbine 19 is driven by the combustion gas generated by the gas turbine combustor 18.

  The exhaust gas discharged from the turbine 19 is discharged from the chimney 22 into the atmosphere after being supplied to the exhaust gas boiler 20 that recovers exhaust heat of the exhaust gas and generates steam.

  The steam generated in the exhaust gas boiler 20 is supplied to a steam turbine 21 constituting a steam turbine device to drive the steam turbine 21. The steam flowing down the steam turbine 21 is cooled by a condenser 26 to become condensed water, and this condensed water is supplied to the exhaust gas boiler 20.

  The coal gasification combined power plant equipped with the carbonized fuel gasification system according to the present embodiment having the above-described configuration will be described in more detail. The coal 1 is produced from the coal hopper 2 by the air separator 4. It is conveyed to the gasification furnace 3 by nitrogen. The oxygen produced by the air separator 4 is supplied to the gasifier 3 as a gasifying agent for the coal 1.

In the gasification furnace 3, the coal 1 is gasified (partially combusted) with oxygen produced by the air separator 4 to generate a product gas 5 mainly composed of CO and H ₂ . Coal 1 contains about 10 wt% of ash (inorganic matter).

  Since the produced gas 5 generated in the gasification furnace 3 is used as a gaseous fuel for power generation, it must be separated from ash. Therefore, the combustion temperature in the gasification furnace 3 is raised to the melting point of ash or higher, and the ash is made into molten slag.

  In the gasification furnace 3, the gaseous product gas 5 is extracted from the gasification furnace 3 upward, and the liquid molten slag is extracted downward from the gasification furnace 3, whereby the product gas 5 is extracted from the coal 1. For this reason, the temperature of the product gas 5 at the outlet of the gasification furnace 3 reaches 1000 ° C. or more.

  In order to use the generated gas 5 as a gaseous fuel, a purification process for removing impurities such as dedusting, desalting, and desulfurization is required. For this purpose, the product gas 5 needs to be cooled to less than 400 ° C. The product gas 5 emitted from the gasification furnace 3 is also accompanied by particulate char composed of unburned carbon and ash.

Also, in the process of cooling the product gas 5 of 1000 ° C. or higher, the molten ash adheres to the heat transfer tube (slagging), and the deposited alkali metal salt (Na ₂ SO ₄ etc.) adheres to the heat transfer tube (fouling). It is necessary to prevent such troubles.

  For this reason, the heat recovery unit 7 for cooling the generated gas 5 is provided in the upper part of the gasification furnace 3. A heat transfer tube is not installed inside the heat recovery section 7, and the product gas 5 is cooled to 800 to 900 ° C. with a water cooling wall. This is to prevent slugging and fouling.

  The product gas 5 that has exited the heat recovery section 7 is supplied to a dust removing device 8 installed on the downstream side of the gasification furnace 3 for dust removal, and the char 9 is recovered. The char 9 recovered from the product gas 5 by the dust removing device 8 is supplied to the char hopper 25, stored in the char hopper 25, and transported to the nitrogen supplied from the air separator 4 in the same manner as the coal 1 to be fed to the char hopper 25. To the gasification furnace 3 through the char supply system d.

  The product gas 5 after being dedusted by the dust removing device 8 is cooled to 300 ° C. or less by the product gas heat exchanger 10 installed on the downstream side of the dust removing device 8, and further the product gas heat exchanger 10. Are supplied to the venturi 11 and the water-washing tower 13 installed on the downstream side, respectively, and cooled to about 100 ° C.

  In the water washing tower 13, the halogen-based material contained in the generated gas 5 and fine dust that could not be collected by the dust removing device 8 are removed. Further, the sulfur content in the product gas 5 is removed by the desulfurization device 17 installed on the downstream side of the water washing tower 13. The sulfur content recovered from the product gas 5 by the desulfurization device 17 is incinerated in the sulfur content combustion furnace 23.

  The product gas 39 desulfurized by the desulfurization device 17 is cooled to about 40 ° C., is supplied from the desulfurization device 17 to the heat exchanger 10 for the product gas, and is reheated to form a gas turbine combustor constituting the gas turbine device. 18 is supplied as fuel.

  Here, the product gas 39 desulfurized by the desulfurization device 17 is mixed with the air supplied from the compressor 24 by the gas turbine combustor 18 and burned to generate high-temperature combustion gas.

  The combustion gas generated in the gas turbine combustor 18 drives the turbine 19, the combustion exhaust gas discharged from the turbine 19 is supplied to the exhaust gas boiler 20, the exhaust heat of the combustion exhaust gas is recovered by the exhaust gas boiler 20, and the exhaust gas boiler 20 The steam turbine 21 is driven by the steam generated in the above.

  On the other hand, since the molten slag formed in the gasification furnace 3 is 1200 ° C. or higher, it is cooled and recovered as solid slag 6 from the gasification furnace 3. In the coal gasification combined power plant equipped with the carbon fuel gasification system of the present embodiment, the molten slag is rapidly cooled with the slag cooling water 14 and recovered as an amorphous (glassy) granulated slag. Show.

  A slag cooling water storage unit 12 for storing slag cooling water 14 is installed directly under the gasification furnace 3. The slag cooling water 14 stored in the slag cooling water storage section 12 is heated by the molten slag flowing down at a high temperature to become high-temperature water 15. The high-temperature water 15 includes solids such as slag and char floating in the water. Will be.

  Therefore, it is necessary to extract the high-temperature water 15 heated in the slag cooling water reservoir 12 and treat the solid matter 30 such as slag and char.

  It is convenient to operate the high-temperature water 15 heated in the slag cooling water storage unit 12 at less than 100 ° C. (for example, 80 ° C.) that does not boil even under normal pressure. In this case, the mass flow rate of the high-temperature water 15 reaches about 0.5 to 2 times that of coal (varies depending on ash content, melting point, etc.).

  Accordingly, the coal gasification combined power plant equipped with the carbonized fuel gasification system according to the first embodiment of the present invention shown in FIG. 1 has slag cooling for cooling the produced gas 5 generated in the gasification furnace 3. A water treatment system c that treats the high-temperature water 15 heated in the water reservoir 12 is disposed.

  The water treatment system c that treats the high-temperature water 15 includes a slurry pump 58 that pumps the high-temperature water 15 heated in the slag cooling water storage unit 12, and the slag cooling water supplied to the slag cooling water storage unit 12. The high-temperature water 15 heated by the slag cooling water reservoir 12 becomes the high-temperature water 27 containing solids such as slag and char floating in the water by the molten slag flowing down at a high temperature as described above. The pump 58 is pressurized, and high temperature water 27 containing solids is supplied into the product gas 5 downstream of the gasification furnace 3 through the water treatment system c.

  The water treatment system c is connected to the downstream side of the heat recovery unit 7 installed in the upper part of the gasification furnace 3, and high-temperature water 27 containing solids introduced through the water treatment system c is supplied to the gasification furnace 3. Or supplied into the product gas 5 discharged from the gasification furnace 3 and flows into the dedusting device 8.

  By providing the water treatment system c that treats the high-temperature water 15 described above, the high-temperature water 15 that has heated the slag cooling water 14 in the slag cooling water reservoir 12 is pumped through the water treatment system c by the slurry pump 58 and is solidified. The high-temperature water 27 containing substances is supplied to the gasification furnace 3 or the dust removing device 8 on the downstream side of the gasification furnace 3 to be used for cooling the product gas 5.

  In the combined coal gasification combined power plant equipped with the carbonized fuel gasification system of the present embodiment, the water treatment is performed from the slag cooling water storage unit 12 to the downstream side of the heat recovery unit 7 installed in the upper part of the gasification furnace 3. Although the structure which supplies the high temperature water 27 containing a solid substance through the system | strain c is described, the said water treatment system | strain c is supplied so that the high temperature water 27 containing a solid substance may be supplied in the heat recovery part 7 of the gasification furnace 3. FIG. It may be arranged.

  As shown in the coal gasification combined power plant provided with the carbonized fuel gasification system of the present embodiment, the high temperature water 15 (high temperature water 27 containing solids) from the slag cooling water reservoir 12 through the water treatment system c. Is pumped by the slurry pump 58 and mixed with the product gas 5 generated in the gasification furnace 3, the following four effects are obtained.

  The first effect is reduction of equipment cost and construction cost. By using the latent heat of vaporization and sensible heat of the high-temperature water 15 supplied from the slag cooling water storage section 12 through the water treatment system c, the generated gas 5 emitted from the gasification furnace 3 is cooled, so that the heat of the gasification furnace 3 is obtained. The collection unit 7 can be downsized.

  The second effect is an improvement in energy efficiency by using exhaust heat of the high-temperature water 15 (the high-temperature water 27 containing solid matter) supplied from the slag cooling water storage unit 12 through the water treatment system c. Furthermore, since the temperature of the high-temperature water 15 supplied from the slag cooling water reservoir 12 through the water treatment system c is higher than the normal temperature, the high-temperature water 15 is easily evaporated when mixed with the product gas 5 generated in the gasification furnace 3. It is also advantageous for cooling.

  The third effect is the reduction of waste and carbon loss. The solids 30 such as slag and char which are contained in the high-temperature water 15 (high-temperature water 27 containing solids) supplied from the slag cooling water reservoir 12 through the water treatment system c are discharged from the gasifier 3. Mixed with the produced gas 5. And the solid substance 30 contained in this high temperature water 15 is collect | recovered with the dust removal apparatus 8, and the weight of the solid substance 30 used as the waste is reduced by re-injecting into the gasification furnace 3 with the char 9 from the char hopper 25. it can. Furthermore, the carbon loss contained in the solid 30 can also be reduced.

The fourth effect is an increase in the H ₂ concentration in the product gas 5 generated in the gasification furnace 3 by promoting the shift reaction. The shift reaction formula is shown in Formula (1).

CO + H ₂ O → CO ₂ + H ₂ (1)
It is known that this shift reaction proceeds in an atmosphere exceeding 1000 ° C. Therefore, when the product gas 5 immediately after leaving the gasification furnace 3 is sprayed with water on the product gas 5 in the product gas cooling unit 7, for example, an increase in the H ₂ concentration in the product gas 5 due to the shift reaction is expected. The

As described in the fifth embodiment, which will be described later, if CO ₂ recovery means from the product gas 5 generated in the gasification furnace 3 is installed, the main component of the product gas 5 is H ₂ . The product gas 5 which has become the main component H ₂ can be used not only for the gaseous fuel for power generation but also for chemical raw materials such as methanol and ammonia.

  In the carbon-based fuel gasification system of the present embodiment having the above-described configuration, the high-temperature water 15 supplied from the slag cooling water reservoir 12 through the water treatment system c and the product gas 5 generated in the gasification furnace 3 are mixed. By effectively cooling the generated gas 5, effects such as simplification of the system configuration, improvement of energy efficiency by using exhaust heat, reduction of waste, and high added value of the generated gas 5 can be expected.

  According to the present embodiment, the exhaust gas generated from the gasification furnace is cooled by efficiently using the exhaust heat of the high temperature water generated in the gasification system, and the carbon loss and waste generated from the carbon-based fuel are reduced. The planned carbon fuel gasification system can be realized.

  Next, a combined coal gasification combined power plant equipped with a carbon fuel gasification system according to a second embodiment of the present invention will be described with reference to FIG. The coal gasification combined cycle power plant having the carbon fuel gasification system of the present embodiment shown in FIG. 2 is a coal gasification system having the carbon fuel gasification system of the first embodiment shown in FIG. Since the basic configuration is the same as that of the combined power plant, description of the configuration common to both is omitted, and different configuration will be described below.

  In the carbonized fuel gasification system of this embodiment shown in FIG. 2, the high-temperature water 15 heated by the molten slag in the slag cooling water reservoir 12 immediately below the gasifier 3 is supplied from the slag cooling water reservoir 12. It is drawn out through the water supply system c and supplied to the solid material separation unit 29 installed in the water supply system c, and the solid material 30 contained in the high-temperature water 15 is separated by the solid material separation unit 29.

  The high temperature water 31 from which the solid matter has been separated by the solid matter separation unit 29 is pumped by the pump 16 installed in the water supply system c, and the dust is removed from the downstream side of the gasification furnace 3 through the water supply system c. The product gas taken out from the gasification furnace, which is a region reaching the apparatus 8, is supplied to a product gas flow path through which the product gas flows down, and is mixed with the product gas 5 to cool the product gas 5.

  The carbon-based fuel gasification system according to the present embodiment uses high-temperature water 31 obtained by separating solids in a solid-material separation unit 29 provided in a water supply system c that draws high-temperature water 31 that has been heated from the slag cooling water storage unit 12. The case where it supplies to the downstream of the heat recovery part 7 provided in the gasification furnace 3 through the said water supply system c is shown.

  On the other hand, the solid material 30 separated from the high temperature water 31 by the solid material separation unit 29 provided in the water supply system c is reintroduced into the gasifier 3 from the solid material separation unit 29 through the solid material supply system d.

  Here, the solid 30 is fine slag or char 9. The combustible component (mostly carbon) in the char 9 re-introduced into the gasification furnace 3 is gasified in the gasification furnace 3 to become a product gas 5.

  The ash and slag in the char 9 are melted into slag and flow down to the cooling water storage unit 12 provided at the lower part of the gasification furnace 3, and are recovered as slag 6.

  In the gasification system for carbon-based fuel according to the present embodiment, the high-temperature water 15 drawn out from the slag cooling water reservoir 12 contains a large amount of solid matter 30, and the high-temperature water 15 containing a large amount of this solid matter 30 is used as the gasifier. 3 is effective when it is difficult to supply directly to the downstream side of 3 or the upstream side of the dust removing unit 8.

  That is, there are many solids 30 contained in the high-temperature water 15 drawn out from the slag cooling water reservoir 12, and the slurry pump 58 provided in the water supply system c to pressurize the high-temperature water 15 cannot be used, or water is supplied to the generated gas 5. There is a possibility that the nozzle for spraying the high-temperature water 15 supplied through the system c is blocked, or that the heat recovery unit 7 that supplies the high-temperature water 15 through the water supply system c or the piping that causes the product gas 5 to flow down may be damaged. Is the case.

  According to the present embodiment, the exhaust gas generated from the gasification furnace is cooled by efficiently using the exhaust heat of the high temperature water generated in the gasification system, and the carbon loss and waste generated from the carbon-based fuel are reduced. The planned carbon fuel gasification system can be realized.

  Next, a combined coal gasification combined power plant equipped with a carbonaceous fuel gasification system according to a third embodiment of the present invention will be described with reference to FIG. The coal gasification combined power plant provided with the carbon fuel gasification system of the present embodiment shown in FIG. 3 is a coal gasification equipped with the carbon fuel gasification system of the first embodiment shown in FIG. Since the basic configuration is the same as that of the combined power plant, description of the configuration common to both is omitted, and different configuration will be described below.

  In the carbon-based fuel gasification system of this embodiment shown in FIG. 3, the high-temperature water 15 heated by the molten slag in the slag cooling water reservoir 12 immediately below the gasification furnace 3 is supplied from the slag cooling water reservoir 12. It is drawn out through the water supply system c and supplied to the solid material separation unit 29 installed in the water supply system c, and the solid material 30 contained in the high-temperature water 15 is separated by the solid material separation unit 29.

  The solid material 30 separated from the high-temperature water 31 by the solid material separation unit 29 is supplied from the solid material separation unit 29 to the chirp hopper 25 through the solid material supply system e, and the product gas 5 taken out from the gasification furnace 3 is removed. The char 9 recovered from the dust removing device 8 and the char hopper 25 are mixed.

  The solid material 30 is transported together with the char 9 by nitrogen supplied from the air separator 4, and is reintroduced from the char hopper 25 into the gasification furnace 3 through the char supply system b.

  The advantage of the gasification system for carbon-based fuel of the present embodiment is that the conventional operation method can be applied to the gasification furnace 3 because the solid material 30 is supplied to the gasification furnace 3 by the existing char supply system b. is there.

  However, the process of heating the solid 30 is required. The char 9 collected by the dedusting device 8 keeps the char hopper 25 and the char supply system b to the gasification furnace 3 to prevent moisture condensation. Therefore, it is necessary to heat the solid 30 to the same degree as the char 9 (about 200 ° C.).

  According to the present embodiment, the exhaust gas generated from the gasification furnace is cooled by efficiently using the exhaust heat of the high temperature water generated in the gasification system, and the carbon loss and waste generated from the carbon-based fuel are reduced. The planned carbon fuel gasification system can be realized.

  Next, a coal gasification combined power plant equipped with a carbon fuel gasification system according to a fourth embodiment of the present invention will be described with reference to FIG. The coal gasification combined cycle power plant having the carbon fuel gasification system of this embodiment shown in FIG. 4 is the same as the coal gasification power plant having the carbon fuel gasification system of the first embodiment shown in FIG. Since the basic configuration is the same as that of the combined power plant, description of the configuration common to both is omitted, and different configuration will be described below.

  In the carbon fuel gasification system of this embodiment shown in FIG. 4, the product gas 5 dedusted by the dedusting device 8 is desulfurized by the heat exchanger 10 installed downstream of the dedusting device 8. 17 is cooled to 300 ° C. or less by the product gas 5 that has passed through 17, and further supplied to the venturi 11 and the water washing tower 13 installed on the downstream side of the heat exchanger 10 to be cooled to about 100 ° C.

  In the venturi 11 and the washing tower 13, the product gas 5 is cooled by gas-liquid contact with liquid cooling water which is makeup water 36 replenished to the venturi 11 and the washing tower 13 from the outside. The cooling water of the venturi 11 and the washing tower 13 is heated to 100 ° C. or more by the generated gas 5 in the process of cooling the generated gas 5. The total flow rate of these cooling waters reaches about 1 to 2 times the supply amount of coal 1 to the gasification furnace 3.

  If the temperature of the cooling water is 100 ° C. and the flow rate is the same as the supply amount of coal 1, the sensible heat of the cooling water heated by gas-liquid contact with the product gas 5 in the venturi 11 and the washing tower 13 is coal. About 1% of the total calorific value.

  Therefore, in the carbonized fuel gasification system of the present embodiment, a part of the cooling water heated by the gas-liquid contact between the product gas and 5 in the venturi 11 and the washing tower 13 is extracted from the venturi 11 and the washing tower 13, respectively. A part of the cooling water heated from the venturi 11 and the water washing tower 13 is sprayed on a region between the outlet of the gasification furnace 3 and the dust removing device 8 to cool the product gas 5 taken out from the gasification furnace 3. Heated water supply systems f1 and f2 were respectively provided.

  Cooling water that cools the product gas 5 by spraying from the venturi 11 and the water washing tower 13 to the region between the outlet of the gasification furnace 3 and the dedusting device 8 through the heated water supply systems f1 and f2 During mixing, it is easy to evaporate together with its own sensible heat, and the product gas 5 can be cooled efficiently.

  The temperature rising water including the water supply system c that supplies the high temperature water 31 separated from the solid material 30 by raising the temperature in the slag cooling water reservoir 12 in the carbon fuel gasification system of the first embodiment. The high-temperature cooling water supplied by the supply systems f1 and f2 may be collected into one system, or may be sprayed on the product gas 5 while maintaining a plurality of systems.

  From the viewpoint of easiness of evaporation of the cooling water, a method of spraying and cooling the generated gas 5 using a plurality of systems of the water supply system c and the heated water supply systems f1 and f2 is preferable. Hot water 31 (below 100 ° C. in the first embodiment described above) separated from the solid 30 is supplied to the upstream side where the temperature of the product gas 5 is high through the water supply system c, and the venturi 11 and the washing tower 13 are provided downstream. A carbon fuel gasification system that supplies high-temperature cooling water (100 ° C. or higher) through the heated water supply systems f1 and f2 is recommended.

  This is achieved by spraying the product gas 5 on the upstream side in the region between the outlet of the gasification furnace 3 and the dust removing device 8 with the high temperature water 31 from which the solids 30 have been separated through the water supply system c. Is considered to be lowered to about 400 to 700 ° C. (varies depending on the properties of coal 1, the flow rate and temperature of high-temperature water 31 from which solid 30 is separated, the evaporation rate, etc.).

  In order to cool the product gas 5 by further water spraying, it is preferable to use the venturi 11 that is high in temperature and easily evaporated and the cooling water 33 and 35 that have been heated to high temperature in the washing tower 13 to cool the product gas 5.

  Therefore, the cooling water 33 and 35 heated at the venturi 11 and the rinsing tower 13 are extracted so that the product gas 5 can be maintained at a predetermined temperature of less than 400 ° C., and the outlet of the gasifier 3 is connected through the heated water supply systems f1 and f2. A carbonized fuel gasification system that suppresses the generation of condensed water in the dedusting device 8 by adjusting the flow rate of the cooling water 33 and 35 sprayed on the product gas 5 on the downstream side in the region between the dedusting device 8 Can be built.

  Below, the system of the cooling water of the venturi 11 and the water-washing tower 13 in the gasification system of the carbon-type fuel of a present Example is demonstrated.

  Since the cooling water 33 of the venturi 11 is heated to a high temperature by gas-liquid contact with the product gas 5 reaching nearly 300 ° C., the cooling water 33 is cooled to room temperature by the high-temperature heat exchanger 32 and is reintroduced into the venturi 11.

  The temperature of the cooling water 33 of the venturi 11 heated to the venturi 11 reaches about 150 ° C. By extracting a part of the cooling water 33 of the venturi 11 that has been heated from the venturi 11 and spraying and mixing the cooling water 33 from the venturi 11 to the product gas 5 on the downstream side of the gasification furnace 3 through the heating water supply system f1. The generated gas 5 can be effectively cooled using the latent heat of vaporization and sensible heat of the cooling water 33.

  In particular, the temperature of a portion 33 of the cooling water of the venturi 11 is about 150 ° C., and is easier to evaporate and handle than normal temperature water. In order to secure the flow rate of the cooling water 33 of the venturi 11, the makeup water 36 is supplied from the outside downstream of the high-temperature heat exchanger 32 and supplied to the venturi 11.

  As for the cooling water 35 of the washing tower 13, a part of the cooling water 35 may be used for cooling the product gas 5, similarly to the cooling water 33 of the venturi 11.

  That is, a part of the cooling water 35 of the water-washing tower 13 that has been heated is extracted from the water-washing tower 13, and the cooling water 35 is sprayed from the water-washing tower 13 to the product gas 5 on the downstream side of the gasification furnace 3 through the heating water supply system f 2. By mixing, the product gas 5 can be effectively cooled using the latent heat of vaporization and sensible heat of the cooling water 35.

  Although the temperature of the cooling water 35 of the water washing tower 13 which exits the water washing tower 13 is about 100 ° C., which is lower than the cooling water 33 of the venturi 11 described above, it is easier to evaporate than water at normal temperature, and the features that are easy to handle are the same. In addition, in order to secure the flow rate of the cooling water 35 in the washing tower 13, the makeup water 36 is supplied from the outside downstream of the low-temperature heat exchanger 34 and is supplied to the washing tower 13.

  As described above, in the carbon fuel gasification system of the present embodiment, the water supply system c that supplies the high-temperature water 31 generated in the slag cooling water reservoir 12 of the gasification furnace 3, the venturi 11, and the washing tower 13 The heated water supply systems f1 and f2 for supplying the generated high-temperature water 33 and 35 are disposed and supplied to the downstream side of the gasification furnace 3 or the upstream side of the dedusting device 8 to be supplied to the gasification furnace 3. By adopting a configuration that is used for cooling the generated product gas 5, it is possible to achieve both energy efficiency improvement by utilizing exhaust heat of the plant and cost reduction by downsizing the heat recovery section that cools the product gas 5. Become.

  According to the present embodiment, the exhaust gas generated from the gasification furnace is cooled by efficiently using the exhaust heat of the high temperature water generated in the gasification system, and the carbon loss and waste generated from the carbon-based fuel are reduced. The planned carbon fuel gasification system can be realized.

  Next, a combined coal gasification combined power plant equipped with a carbonaceous fuel gasification system according to a fifth embodiment of the present invention will be described with reference to FIG. The coal gasification combined power plant having the carbon fuel gasification system of the present embodiment shown in FIG. 5 is the same as the coal gasification power plant having the carbon fuel gasification system of the first embodiment shown in FIG. Since the basic configuration is the same as that of the combined power plant, description of the configuration common to both is omitted, and different configuration will be described below.

The carrier medium of coal 1 and char 9 to the gasification furnace 3, using a portion of the CO 2 ₅₂ recovered in later to the CO ₂ recovery unit. This CO ₂ is defined as CO ₂ 53 for recharging the gasifier.

By changing the carrier medium from N ₂ to CO ₂ , the CO ₂ concentration in the gasification furnace 3 is increased, and the CO ₂ gasification reaction represented by the formula (2) is promoted. Thus, the reduction of O ₂ consumption is gasifying agent is expected.

C + CO ₂ → 2CO (2)
The reduction in the amount of O ₂ used leads to a reduction in equipment cost due to downsizing of the air separator 4, a reduction in running cost and an improvement in energy efficiency due to a reduction in O ₂ production power.

Next, the main component of the product gas 5 produced in the gasification furnace 3, _CO, is H 2, CO _2. When water is sprayed on the product gas 5 and evaporated, not only the product gas 5 can be cooled, but also the water vapor concentration in the product gas 5 increases.

  Thereby, not only the shift reaction shown in the formula (1) of the first embodiment proceeds, but also the flow rate of the water vapor 41 added in the shift reactor 40 installed on the downstream side of the gasification furnace 3 described later can be reduced.

  In the present embodiment, in order to promote the shift reaction in a high temperature atmosphere of 1000 ° C. or higher, the high temperature water 31 separated from the solid by the solid separation unit 29 installed in the water supply system c is gasified through the water supply system c. It is configured to supply the product gas cooling unit 7 installed in the upper part of the furnace 3.

  The cooling water sprayed on the product gas 5 on the downstream side of the gasification furnace 3 is the high temperature water generated in the coal gasification combined power plant (the slag cooling water storage section 12 is heated) as in the case of the fourth embodiment. High-temperature water 15, a part 37 of cooling water of the venturi 11, a part of cooling water 38 of the washing tower 13, etc.).

  The sensible heat of these high-temperature waters has not been effectively used so far.

  On the other hand, water vapor 41 is installed at the downstream side of the desulfurization unit 17 and added in a shift reactor 40 that causes carbon monoxide and water vapor in the product gas 5 generated in the gasification furnace 5 to react with each other to shift to carbon dioxide and hydrogen. Used for the shift reaction.

  Therefore, if the flow rate of the water vapor 41 added to the product gas 5 can be reduced by the shift reaction device 40, the power for producing the reduced amount of the water vapor 41 can be reduced, leading to reduction in running cost and improvement in energy efficiency.

  The product gas 39 installed at the downstream side of the water washing tower 13 and desulfurized by the desulfurization device 17 for desulfurizing the product gas 5 and cooled to about 40 ° C. includes a heat exchanger 42 for heating the product gas 39 after desulfurization, and The product gas is reheated to 200 ° C. or more by the product gas heater 43 and supplied to the shift reactor 40 in the product gas 5 installed on the downstream side of the desulfurization apparatus 17.

In the shift reactor 40, the water vapor 41 is added to the product gas 39 after desulfurization, and the shift reaction shown in the formula (1) of the first embodiment proceeds. By this shift reaction, CO in the product gas 39 after desulfurization becomes CO ₂ and H ₂ , and the H ₂ concentration increases. Note that the input temperature of the product gas 39 after desulfurization and the steam 41 to the shift reactor 40 is determined by the characteristics of the shift reaction catalyst.

The temperature of the product gas 44 after the shift reaction in the shift reactor 40 is 200 ° C. or more at the outlet of the shift reactor 40. For this reason, the product gas 44 after the shift reaction is cooled to about 150 ° C. by the heat exchanger 42 of the product gas after desulfurization, and is supplied to the CO ₂ absorption tower 45 installed on the downstream side of the shift reactor 40. The

In the CO ₂ absorption tower 45, the product gas 44 after the shift reaction flows into the CO ₂ absorber 45, in contact with CO ₂ absorbing liquid 47 in the CO ₂ absorption tower 45. Thereby, the CO ₂ in the product gas 44 after the shift reaction becomes a product gas 46 which is recovered in the CO ₂ absorbing solution 47 and from which CO ₂ is removed.

Here, the input temperature of the product gas 44 after the shift reaction to the CO ₂ absorption tower 45 is determined by the characteristics of the CO ₂ absorbent 47. The main component of the product gas 46 after CO _{2 is} removed by the CO ₂ absorption tower 45 is H ₂ .

Product gas 46 after CO ₂ removal in the CO ₂ absorber 45 is supplied as fuel from the CO ₂ absorber 45 to the gas turbine combustor 18, and the air for combustion supplied to the gas turbine combustor 18 from the compressor 24 Combusts by mixing, generating hot combustion gas.

  The combustion gas generated in the gas turbine combustor 18 is supplied to the gas turbine 19 to drive the gas turbine 19, and the exhaust gas discharged from the gas turbine 19 is caused to flow down to the boiler 20 so that the exhaust heat of the exhaust gas is reduced. Steam is collected by being recovered by the boiler 20, and the generated steam is supplied to the steam turbine 21 to drive the steam turbine 21.

Further, the CO ₂ absorbing liquid 48 that has absorbed CO ₂ from the product gas 44 in the CO ₂ absorption tower 45 is heated to 100 ° C. or more by the CO ₂ absorbing liquid heat exchanger 49 and the CO ₂ absorbing liquid heater 50. And is supplied to a CO ₂ regeneration tower 51 installed on the downstream side of the CO ₂ absorption tower 45.

In the CO ₂ regeneration tower 51, by releasing the CO ₂ in the CO ₂ absorbing liquid 48 that has absorbed CO _2, it is possible to reuse the CO ₂ absorbing liquid 47.

The _CO 2 52 recovered in CO ₂ regeneration tower 51, the part derived from CO ₂ regeneration tower 51 through the CO ₂ supply line g as _CO 2 53 for reintroduction of the gasification furnace 3 by coal 1 and char is recycled to the transport medium 9, the majority of the CO 2 ₅₂ recovered in CO ₂ regeneration tower 51 is stored and supplies the like in the ground.

Here, in order to keep the CO ₂ recovery rate in the CO ₂ regeneration tower 51 high, it is necessary to keep the CO ₂ absorbent 48 warm. Therefore, a part of the CO ₂ absorbing liquid 48 is extracted from the CO ₂ regeneration tower 51 as a CO ₂ absorbing liquid 54 for regeneration heating, reheated to 100 ° C. or higher by the heat exchanger 55, and then the CO ₂ regeneration tower 51. In

The heat capacity required for the heat exchanger 55 is large, and a low-temperature steam 56 of about 200 to 300 ° C. generated in the boiler 20 is preferably used as a heat source from the boiler 20 to the heat exchanger 55 through the steam supply system i. This low-temperature steam 56 is referred to as heating steam 56 for the CO ₂ absorbent 54.

The sensible heat of the heating steam 56 of the CO ₂ absorbing liquid 48 reheats the CO ₂ absorbing liquid 54 for regeneration heating in the heat exchanger 55. Therefore, the heating steam 56 of the CO ₂ absorbing liquid 54 exiting the heat exchanger 55 is lowered to 200 ° C. or less.

A steam supply system h that supplies the heating steam 56 from the heat exchanger 55 to the downstream side of the gasification furnace 3 is also provided for the heating steam 56 of the CO ₂ absorbent 54 that has exited the heat exchanger 55, It is preferable to supply the heating steam 56 from the heat exchanger 55 to the downstream side of the gasification furnace 3 through the steam supply system h and use it to cool the product gas 5 and promote the shift reaction in the shift reactor 40.

This is because the sensible heat and latent heat of the steam become waste heat if the heating steam 56 of the CO ₂ absorbing liquid 54 exiting the heat exchanger 55 is returned to the condenser 26.

In the combined coal gasification combined power plant equipped with the carbonized fuel gasification system of the present embodiment, the steam for supplying the heating steam 56 of the CO ₂ absorbent 54 exiting the heat exchanger 55 downstream of the gasification furnace 3. A supply system h, a steam supply system i for supplying low-temperature steam 56 from the boiler 20 to the heat exchanger 55, a water supply system c for supplying high-temperature water 15 from the slag cooling water storage section 13, and a cooling water for the venturi 11 Four types of water or steam of the heated water supply systems f1 and f2 for supplying a part 37 and a part of cooling water 38 of the rinsing tower 13 are supplied to the downstream side of the gasification furnace 3 or the upstream side of the dedusting device 8. However, a system capable of supplying at least one kind of water or steam among these systems may be used.

As described above, according to the coal gasification combined power plant provided with the carbonized fuel gasification system of the present embodiment, it is possible to construct a coal gasification combined power plant that does not emit CO _{2 and} has high energy efficiency.

In the coal gasification combined power generation plant including a gas system of carbonaceous fuels of this embodiment, as an example of a CO ₂ recovery unit, the system using a CO ₂ chemical absorption method using the CO ₂ absorbing solution 54 explained.

Further, the CO ₂ recovery means may use a physical absorption method such as membrane separation or an adsorbent method.

  According to the present embodiment, the exhaust gas from the high-temperature water is efficiently used to cool the generated gas from the gasification furnace, and the solid matter in the high-temperature water is recovered by the existing dust removal equipment of the gasification furnace. It is possible to realize a gasification system for a carbon-based fuel that can be re-introduced into the conversion furnace to reduce carbon loss and waste from the carbon-based fuel.

a: fuel supply system, b: char supply system, c: water supply system, d: solid material supply system, e: another solid material supply system, f1, f2: heated water supply system, g: CO ₂ supply system, h: steam supply system, i: steam supply system, 1: coal, 2: coal hopper, 3: gasification furnace, 4: air separator, 5: generated gas, 6: slag, 7: heat recovery unit, 8: Dedusting device, 9: Char, 10: Heat exchanger for generated gas, 11: Venturi, 12: Slag cooling water reservoir, 13: Flush tower, 14: Slag cooling water, 15: High temperature from slag cooling water reservoir Water: 16: Pump, 17: Desulfurizer, 18: Gas turbine combustor, 19: Gas turbine, 20: Exhaust gas boiler, 21: Steam turbine, 22: Chimney, 23: Sulfur content combustion furnace, 24: Compressor, 25: Chirp hopper, 26: Condenser, 27: Contains solids High temperature water, 29: Solid matter separation unit, 30: Solid matter, 31: High temperature water from which solid matter has been separated, 32: High temperature heat exchanger, 33: Venturi cooling water, 34: Low temperature heat exchanger, 35: Washing tower Cooling water, 36: makeup water, 37: part of cooling water for venturi, 38: part of cooling water for washing tower, 39: product gas after desulfurization, 40: shift reactor, 41: steam for shift reaction 42: Heat exchanger for the product gas after desulfurization, 43: Product gas heater after the desulfurization, 44: Product gas after the shift reaction, 45: CO ₂ absorption tower, 46: Product gas after the CO ₂ removal, 47 : CO ₂ absorbing solution, 48: CO ₂ absorbed CO ₂ absorbing solution, 49: CO ₂ absorbing solution heat exchanger, 50: CO ₂ absorbing liquid heater, 51: CO ₂ regeneration tower, 52: recovered CO ₂ , 53: CO ₂ for recharging the gasifier, 54: CO ₂ for regeneration heating Absorption liquid, 55: heat exchanger, 56: steam for heating CO ₂ absorption liquid, 57: cooler for slag cooling water, 58: slurry pump

Claims (6)

A gasification furnace that gasifies solid carbon-based fuel to generate product gas;
A fuel supply system for conveying a solid carbon-based fuel by gas from a coal hopper to the gasifier;
The gasification furnace takes out a product gas generated by gasifying a carbon-based fuel from above the gasification furnace, converts an inorganic substance contained in the carbon-based fuel into molten slag, and takes it out below the gasification furnace. Configure
A dust removing unit installed on the downstream side of the gasification furnace, and dedusting the generated gas taken out from above the gasification furnace;
A char hopper that collects the char that has been dedusted in the dust removing section and accompanied by the product gas;
A char supply system for conveying the char recovered by the char hopper by gas from the char hopper to the gasification furnace;
A water-washing tower that is installed on the downstream side of the dedusting unit and that cleans the generated gas flowing down the dedusting unit;
Installing a slag cooling water reservoir for cooling with cooling water supplied from the outside with molten slag at the bottom of the gasifier;
High temperature water heated by molten slag in the slag cooling water reservoir is supplied from the slag cooling water reservoir to the downstream side of the gasification furnace or upstream of the dedusting section and taken out from the gasification furnace. A carbonized fuel gasification system comprising a water supply system for cooling the produced gas. The gasification system for a carbon-based fuel according to claim 1,
A carbonized fuel gasification system comprising a solid material supply system for transporting the solid material collected by the solid material separation unit to the gasification furnace. The gasification system for a carbon-based fuel according to claim 1,
Disposing another solid material supply system for supplying the solid material collected by the solid material separation unit to the chirp hopper,
A carbon-based fuel gasification system, wherein the solid material supplied to the char hopper through the separate solid material supply system is introduced into the gasification furnace through the char supply system. The gasification system of the carbon-based fuel according to any one of claims 1 to 3,
A venturi for cooling the generated gas taken out from the gasification furnace by gas-liquid contact with cooling water and a washing tower are respectively installed on the downstream side of the dust removing section,
A part of the cooling water of the venturi and a part of the cooling water of the washing tower heated by contact with the product gas taken out from the gasification furnace at the venturi and the washing tower are gasified from the venturi and the washing tower. A carbonized fuel gasification system comprising a heated water supply system that cools the generated gas that is supplied to the downstream side of the furnace or the upstream side of the dedusting section and taken out of the gasification furnace . The gasification system for a carbon-based fuel according to claim 1,
A water-washing tower that is installed on the downstream side of the dust removal unit and that cleans the generated gas flowing down the dust removal unit,
A desulfurization device installed on the downstream side of the washing tower and desulfurizing the generated gas flowing down the washing tower;
Is installed on the downstream side of the desulfurization apparatus, the CO ₂ contained the product gas to the desulfurization unit and flows down the CO ₂ absorption tower for absorbing liquid absorbent, by heating the CO ₂ absorbing solution which has absorbed the CO ₂ CO ₂ Each is provided with a CO ₂ regeneration tower for regenerating the absorption liquid,
Characterized in that disposed CO ₂ supply system for supplying CO ₂ to the coal hopper from the CO ₂ regeneration tower as a solid carbonaceous fuel in the separated CO ₂ in the CO ₂ regeneration tower to convey to the gasifier Carbon fuel gasification system. The gasification system for carbon-based fuel according to claim 5,
The steam used as a heat source of the CO ₂ absorbing solution for regeneration heat withdrawn from the CO ₂ regeneration tower, downstream of the gasifier from the CO ₂ regeneration tower, or supplied to the upstream side of the dust removing unit A gasification system for a carbon-based fuel, wherein a steam supply system for cooling generated gas is provided.

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