JP5704604B2 - Coal gasification power generation facility - Google Patents

Description

  The present invention relates to a coal gasification power generation facility.

  Coal exists in a large area of the world, has a large recoverable reserve, and has a stable price, so it has a high supply stability and a low price per calorific value. As one method of thermal power generation using such coal as a fuel, an integrated coal gas combined cycle (IGCC) is known. In coal gasification combined cycle power generation, power is generated by driving a gas turbine using coal gasification gas obtained by incomplete combustion of coal as fuel, and steam is generated by recovering exhaust heat from the gas turbine. Electric power is obtained by driving the steam turbine with the generated steam (see, for example, Patent Document 1).

  The coal gasification gas generated in the coal gasification furnace contains impurities such as sulfur compounds (sulfides), impurities that affect subsequent devices, and trace components in addition to the carbon monoxide that is burned. The gas purification equipment removes impurities from the coal gasification gas to produce fuel gas.

  As such a gas purification facility, there is a dry-type gas purification facility that removes impurities while maintaining the temperature of the coal gasification gas at a temperature higher than the dew point (see, for example, Patent Document 2). According to such a dry gas purification facility, the coal gasification gas can be purified at a high temperature, so that fuel gas can be obtained while suppressing an increase or decrease in temperature or pressure.

  However, the coal gasification gas generated in the coal gasification furnace is 1000 ° C. or higher, and it is necessary to lower the temperature to a temperature suitable for removing impurities (about 450 ° C.) with a dry gas purification facility. There is a concern that carbon monoxide in the coal gasification gas will precipitate as solid carbon.

  In other words, because the piping from the coal gasifier to the dry gas purification facility and the material of the reactor of the dry gas purification facility contain iron, carbon deposits on the surface of the piping etc. using iron as a catalyst, and the resulting fuel gas There is a risk that calorie may be reduced, and deterioration and damage of the equipment may be induced. In addition, an agent used in the dry desulfurization process, for example, a desulfurization agent such as zinc ferrite for removing sulfur compounds, acts as a catalyst for carbon deposition, and carbon deposition impedes the original desulfurization action of the desulfurization agent. There is a fear.

JP 2005-171148 A JP 2009-173717 A

  In view of such circumstances, the present invention provides a coal gasification power generation facility capable of preventing carbon from being deposited on an impurity remover, piping and the like in a dry gas purification facility for coal gasification gas. Objective.

  In a first aspect for achieving the above object, a coal gasification furnace that generates a coal gasification gas by a reaction of coal and an oxidant, and a temperature of the coal gasification gas generated in the coal gasification furnace, Dry gas refining equipment that removes impurities in coal gasification gas by a dry process that operates while maintaining a temperature above the dew point, combustion means for burning fuel gas obtained in the dry gas refining equipment, and the combustion means A gas turbine that obtains power by expanding combustion gas from the gas, and an exhaust gas of the gas turbine that contains carbon dioxide gas and water vapor as a fluid that suppresses carbon deposition in the dry gas purification facility. And a fluid addition means for adding to the coal gasification gas upstream.

  In the first aspect, it is possible to prevent carbon from being deposited from carbon monoxide in the coal gasification gas on the pipe surface of the dry gas purification facility and the impurity removing agent. Thereby, it is prevented that the removal function of the impurity which a removal agent has is inhibited by carbon deposition, and coal gasification gas can be refine | purified reliably. In addition, since carbon deposition is suppressed on the pipe surface of the dry gas purification facility, deterioration damage of the dry gas purification facility can be suppressed.

  Furthermore, the performance of the desulfurizing agent and the suppression of carbon deposition can be achieved by using the exhaust gas that has worked with the gas turbine in the system.

According to a second aspect of the present invention, in the coal gasification power generation facility described in the first aspect, the exhaust gas has a molar fraction in a reaction condition of carbon dioxide gas and carbon monoxide gas in the coal gasification gas. respectively and x _CO2 and x _CO, and wherein the pressure of the coal gasification gas is P, a fluid to vary the ratio of x _CO2 and x _CO to increase the K _B, defined by the following Expression 1 In the coal gasification power generation facility.

[Equation 1]
_{K B = x CO2 / (x} CO 2 × P)

In the second aspect, it is possible to use a fluid to vary the ratio of x _CO2 and x _CO as the K _B is increased as the fluid to be added in order to suppress carbon deposition.

  According to a third aspect of the present invention, in the coal gasification power generation facility described in the first or second aspect, power is obtained by expanding steam obtained by recovering heat of exhaust gas of the gas turbine. A coal gasification power generation facility comprising a steam turbine.

  In the third aspect, by providing the steam turbine, the power generation efficiency can be further improved.

  ADVANTAGE OF THE INVENTION According to this invention, the coal gasification power generation equipment which can prevent that carbon deposits on the removal agent of impurities, piping, etc. in the dry-type gas purification equipment of coal gasification gas is provided.

1 is a configuration diagram of a coal gasification power generation facility according to Embodiment 1. FIG. 1 is a conceptual diagram illustrating the principle of carbon deposition prevention according to Embodiment 1. FIG. It is a graph which shows the relationship between the exhaust gas added to coal gasification gas, and the amount of carbon deposits. It is a graph which shows the desulfurization performance at the time of adding exhaust gas to coal gasification gas.

  In this embodiment, a coal gasification power generation facility including a gas turbine and a steam turbine will be described as an example of the coal gasification power generation facility.

  FIG. 1 is a configuration diagram of a coal gasification power generation facility according to the present embodiment. As illustrated, the coal gasification power generation facility 1 includes a coal gasification furnace 2. Carbon dioxide from the system is supplied to the coal gasification furnace 2, and coal gasification gas g is generated by a reaction of an oxidant (oxygen, air). By gasifying coal with carbon dioxide and oxygen, the carbon conversion rate in the furnace is greatly increased compared to gasifying coal with air, air with increased oxygen concentration, or oxygen due to the gasification promotion effect of carbon dioxide. To improve.

  The coal gasification gas g contains combustible components such as carbon monoxide and hydrogen gas, and also contains water-soluble impurities, condensable impurities, particulate impurities, and gaseous impurities. By gasifying coal with carbon dioxide and oxygen, carbon monoxide and hydrogen contained in the coal gasification gas g have a higher concentration than when gasifying coal with air. The coal gasification gas g is dedusted by a dust removing means (not shown), adjusted to a predetermined temperature by the heat exchanger 3, and sent to the dry gas purification facility 4.

  The dry gas purification equipment 4 removes the impurities of the coal gasification gas g by a dry method that operates while maintaining the temperature of the coal gasification gas g above the dew point. In the present embodiment, the dry gas purification facility 4 includes a halide removing device 5 and a desulfurizing device 6 as an example of a removing device that removes impurities.

  The halide removing device 5 includes a halide absorbent that chemically reacts with a halide contained in the coal gasification gas g. As the halide absorbent, one containing alkali aluminate, which is a composite oxide of aluminum and an alkaline substance, and containing a strength reinforcing additive can be used. It is also possible to use a halide absorbent other than the alkali aluminate.

The desulfurization device 6 includes a metal oxide desulfurization agent that chemically reacts with a sulfur compound contained in the coal gasification gas g. The metal oxide desulfurization agent can remove sulfur compounds such as carbonyl sulfide (COS) and hydrogen sulfide (H ₂ S) to a low concentration. The metal oxide desulfurization agent only needs to contain a metal oxide that chemically reacts with a sulfur compound. For example, a desulfurization agent mainly composed of iron oxide, a desulfurization agent mainly composed of zinc ferrite, and zinc oxide. A desulfurizing agent having a main component can be used.

  As the dry gas purification equipment 4, in addition to the halide removing device 5 and the desulfurization device 6 described above, an ammonia removing device for removing ammonia contained in the gas and a mercury removing device for removing mercury contained in the gas are used. It may be used.

  When the coal gasification gas g is sent to the dry gas purification equipment 4 as described above, the halide is removed by the halide removing device 5, the sulfur compound is removed and purified by the desulfurization device 6, and the fuel gas f is obtained. .

  The fuel gas f is sent to the combustor 7. Further, high-concentration oxygen produced by the oxygen production apparatus 8 is sent to the combustor 7 and the fuel gas f is combusted. The oxygen produced by the oxygen production apparatus 8 is also supplied to the coal gasification furnace 2. The oxygen production apparatus 8 supplies, for example, equipment in which nitrogen gas is concentrated by pressure swing adsorption and is removed from the air and pressurized oxygen is supplied, or oxygen from a cryogenic equipment is pressurized to a predetermined pressure and supplied. Equipment can be applied.

  Combustion gas generated by combustion in the combustor 7 is sent to the gas turbine 10 and expanded to obtain power generation. The exhaust gas e (working fluid containing carbon dioxide as a main component) that has finished work in the gas turbine 10 is heat recovered by the exhaust heat recovery boiler (HRSG) 11, and the exhaust gas e recovered by the HRSG 11 is recovered by the compressor 9. The exhaust gas e that has been compressed and compressed by the compressor 9 is heated by the regenerative heat exchanger 12 and is introduced into the combustor 7. A part of the exhaust gas e from the gas turbine 10 is sent to the regenerative heat exchanger 12 and heat recovery of the exhaust gas e is performed.

  Further, a part of the exhaust gas e recovered by heat by the HRSG 11 is recovered by a carbon dioxide recovery system described later.

  Since the exhaust gas e on the outlet side of the gas turbine 10 is a working fluid mainly composed of carbon dioxide gas, the specific heat ratio is small, the temperature difference between the inlet and outlet of the compressor 9 and the gas turbine 10 is reduced, and the regenerative heat exchanger 12. The thermal efficiency due to can be greatly improved. That is, the system is easy to obtain the effect of thermal efficiency by regeneration.

  Steam generated by the HRSG 11 is sent to the steam turbine 13 and expanded by the steam turbine 13 to obtain power. The compressor 9 and the gas turbine 10 and the steam turbine 13 described above are connected in a coaxial state, and a generator 14 is connected to the steam turbine 13. The generator 14 is driven by the power of the gas turbine 10 and the steam turbine 13 connected in series, and combined power generation by the gas turbine 10 and the steam turbine 13 is performed.

  The exhaust steam that has finished its work in the steam turbine 13 is condensed in a condenser 15 and sent to a feed water heater 16 by a feed water pump (not shown). A part of the exhaust gas e heat recovered by the HRSG 11 is sent to the feed water heater 16, and the condensed water condensed by the condenser 15 is heated by the recovered heat and supplied to the HRSG 11.

Carbon dioxide is recovered from a part of the exhaust gas heat recovered by the HRSG 11 by a carbon dioxide recovery system. That is, after the exhaust gas e (gas containing CO ₂ ) is cooled by the feed water heater 16, the moisture is separated by the brackish water separator (cooler) 17, and the exhaust gas e (CO ₂ ) from which the moisture is separated. Is pressurized to a predetermined pressure by the compressor 18 and further cooled by a brackish water separator (cooler) 19. The exhaust gas e (CO ₂ ) from which moisture has been removed by cooling is pressurized to a predetermined pressure by the compressor 20 and sent to the coal gasification furnace 2. Excess CO ₂ is recovered by pressurizing and liquefying.

  The coal gasification furnace 2 is supplied with the fluid of the compressor 9 extracted as an oxidant (A). A part of the condensate from the condenser 15 is supplied to the heat exchanger 3 (B), steam is generated by heat exchange with the coal gasification gas g, and the generated steam is sent to the steam turbine 13. (C).

  In the coal gasification power generation facility 1 described above, in the coal gasification furnace 2, a coal gasification gas g is generated by a reaction between the oxidant, coal, oxygen sent from the oxygen production apparatus 8, and the recovered carbon dioxide gas. The coal gasification gas g is refined by the dry gas purification equipment 4 to obtain a fuel gas f, and the fuel gas f is sent to the combustor 7 and is burned with oxygen in the combustor 7 so as to have a specific heat ratio mainly composed of carbon dioxide. A small combustion gas (working fluid) is obtained, and the combustion gas from the combustor 7 is expanded by the gas turbine 10 to obtain power generation power. The exhaust gas e that has finished its work in the gas turbine 10 is heat recovered by the HRSG 11, and the steam generated from the HRSG 11 and the heat exchanger 3 is sent to the steam turbine 13 to obtain a power generation output. A part of the exhaust gas e is sent to the regenerative heat exchanger 12 for heat recovery, and sent to the coal gasification furnace 2 for use in or gasification of coal.

  Here, the fluid adding means will be described. The fluid addition means adds the exhaust gas e of the gas turbine 10 mainly composed of carbon dioxide gas and water vapor to the coal gasification gas g upstream of the desulfurization device 6 as a fluid for suppressing carbon deposition in the desulfurization device 6. To do.

  Specifically, the fluid adding means is configured to supply a part of the exhaust gas e compressed by the compressor 9 to the pipe 21 (D). The place where the exhaust gas e is added to the coal gasification gas g is the pipe 21 on the upstream side of the desulfurization device 6 (dry gas purification equipment 4) and downstream of the heat exchanger 3.

  The pressure of the exhaust gas e added to the pipe 21 is equal to or higher than the pressure of the coal gasification gas g sent to the pipe 21. Here, in the compressor 9, the pressure of the exhaust gas e is set so as to be equal to the pressure of the coal gasification gas g purified by the dry gas purification facility 4. On the other hand, the coal gasification gas g does not have a large pressure loss before and after the dry gas purification facility 4. That is, the pressure of the exhaust gas e compressed by the compressor 9 is almost equal to the pressure of the coal gasification gas g in the pipe 21. Therefore, as a configuration of the fluid adding means, it is most preferable to supply the exhaust gas e from the compressor 9 to the pipe 21. If the pressure of the exhaust gas e exhausted by the gas turbine 10 can be made equal to or higher than the pressure of the coal gasification gas g in the pipe 21, it is limited to the case where the compressor 9 boosts the exhaust gas e. Absent.

  In addition, the temperature of the exhaust gas e added to the pipe 21 is preferably equal to the temperature of the coal gasification gas g sent to the pipe 21. This is because the temperature of the coal gasification gas g is adjusted to the operating temperature of the dry gas purification facility 4. The temperature of the exhaust gas e is not limited to the same as the temperature of the coal gasification gas g. For example, the exhaust gas e may be added to the coal gasification gas g in the pipe 21, and then the temperature may be adjusted to the operating temperature of the dry gas purification equipment 4.

The flow rate of the exhaust gas e to be added to the coal gasification gas g is the rate needed to increase the K _B shown in Formula 2. That is, when the molar fraction of carbon dioxide gas and carbon monoxide gas in the coal gasification gas g before taking the fluid addition means is x _CO2 and x _CO , respectively, and the pressure of the coal gasification gas g is P, the K _B as number 2 is represented by a function of their molar fraction and the total pressure. When exhaust gas is added upstream of the dry gas purification equipment 4, _xCO2 increases and _xCO decreases. Since that time the value of x _CO2 and x _CO can be calculated from the composition and the mixing ratio of the exhaust gas and the composition of the coal gasification gas, the exhaust gas e in the rate needed to the desired value of K _B in the suppression of carbon deposition Is added to the coal gasification gas g.

[Equation 2]
_{K B = x CO2 / (x} CO 2 × P)
(If the partial pressure of carbon dioxide is P _CO2 and the partial pressure of carbon monoxide is P _CO , then P _CO2 = x _CO2 × P and P _CO = x _CO × P, so K _B = P _CO2 / (P _CO) can ² both represent. detailed description of the same formula, refer to the description herein late K _B.)

The total pressure P is the operating pressure of the dry desulfurization process in which the high-pressure coal gasification gas g determined according to the operating conditions of the coal gasification furnace 2 is circulated and refined. because those who were fed to the gas turbine is also improved high power generation output is obtained the power generation efficiency, it is undesirable to lower the P for the purpose of increasing the K _B. Further, the composition of the coal gasification gas g, so determined by the characteristics of the coal gasification furnace 2, it is impossible to change the x _CO2 and x _CO prior to take fluid adding means freely. Therefore, the exhaust gas e by adding to the coal gasification gas g, varying the ratio of x _CO2 and x _CO to increase the K _B is reasonable and method for enhancing the appropriate K _B.

  As described above, by adding the exhaust gas e to the coal gasification gas g, it is possible to prevent carbon from being deposited on the pipe surface of the desulfurization apparatus 6 and the desulfurization agent. The principle by which carbon deposition is prevented by the desulfurization apparatus 6 will be described with reference to FIG.

As shown in the drawing, in the pipe 21, the exhaust gas e supplied from the compressor 9 is added to the coal gasification gas g sent from the coal gasification furnace 2. The water vapor contained in the exhaust gas e advances the aqueous shift reaction shown in the following reaction formula (a) from the left side to the right side (1). This reduces the molar fraction _{x CO} of carbon monoxide, since the mole fraction _{x CO2} of carbon dioxide increases, _{K B} is increased (2). When the molar fraction x _CO2 increases, the Boudouard reaction, which is a reaction from carbon monoxide to carbon dioxide and carbon, is suppressed, and carbon deposition is suppressed (3).

CO + H ₂ O → CO ₂ + H ₂ (a)

On the other hand, carbon dioxide contained in the exhaust gas e increases the molar fraction x _CO2 (2). And, like the water vapor, the Boudouard reaction is suppressed (3).

  In this manner, by adding the exhaust gas e containing water vapor and carbon dioxide to the coal gasification gas g, carbon deposition is suppressed in the desulfurization apparatus 6.

  It will be quantitatively described that carbon deposition is suppressed when the exhaust gas e is added to the coal gasification gas g.

When the composition of the main component contained in the coal gasification gas g when coal is gasified with carbon dioxide and oxygen is obtained by chemical equilibrium calculation, it is as shown in Table 1 (1). From typical operating conditions of the coal gasifier, the total pressure P was set at 27.51 bar. The value of _{K B} at this time is 0.0071. The exhaust gas e was added to the coal gasification gas g having this composition. This exhaust gas e consists of carbon dioxide and water vapor, and the flow rate of carbon dioxide is 7.6% of the flow rate of coal gasification gas, and the flow rate of water vapor is 3.0%. The composition of the coal gasification gas g to which such an exhaust gas e is added is (2). Here, the temperature of the exhaust gas e was 900 ° C., and the pressure was set to 2.65 MPa.

Since the ratio of the _{x CO2} and _{x CO} is changed by the addition of exhaust gas e, the value of _{K B} is increased to 0.0148, could effectively inhibit the Boudouard reaction. Furthermore, when the temperature is lowered to a temperature suitable for removing impurities in the dry gas purification equipment 4 (about 450 ° C.) and the water gas shift reaction of Formula 2 proceeds to a chemical equilibrium of 450 ° C., the composition of (3) is obtained. . The value of _{K B} at this time is increased significantly to 0.0231. Thus the addition of exhaust gas e comprising carbon dioxide and water vapor, and by the synergistic effect with the water gas shift reaction proceeds, to vary the ratio of x _CO2 and x _CO so that K _B greatly increased Therefore, the progress of the Boudouard reaction can be suppressed.

  FIG. 3 is a graph showing the relationship between the amount of exhaust gas added and the amount of carbon deposition. The vertical axis represents the ratio (wt%) of the carbon deposition amount to the weight of the desulfurizing agent, and the horizontal axis represents the ratio (%) of the exhaust gas flow rate to the coal gasification gas flow rate.

  As shown in the figure, when the exhaust gas is added to the coal gasification gas, the carbon deposition is zero when the addition amount of the exhaust gas exceeds about 11%.

  Thus, it can be seen that when a certain amount or more of exhaust gas is added, carbon does not precipitate in the desulfurization agent.

  FIG. 4 is a graph showing the relationship between the amount of exhaust gas added and the desulfurization performance. The vertical axis represents the concentration (ppm) of the sulfur compound contained in the gas at the outlet of the desulfurizer 6. The horizontal axis represents the dimensionless time in which the theoretical amount of sulfur compound that can be removed from the desulfurizing agent is “1” and the time when the gas is actually supplied is expressed as a ratio. The amount of exhaust gas added to the coal gasification gas is 10%.

  As shown in the figure, when the exhaust gas is added to the coal gasification gas, the sulfur concentration is almost zero until the dimensionless time is around 0.8. When the dimensionless time becomes 0.9, the sulfur concentration starts to show an upward trend. Thereafter, even when the dimensionless time exceeds about 1.0, the sulfur concentration continues to increase, and the upward trend is stopped when the dimensionless time is near 1.2.

  Thus, even when the exhaust gas is added to the coal gasification gas, it can be seen that the desulfurization agent maintains the desulfurization performance for a certain period until the dimensionless time reaches 1.

  As described above, the coal gasification power generation facility 1 according to the present embodiment uses the exhaust gas e from the gas turbine 10 to the coal gasification gas g supplied from the coal gasification furnace 2 prior to dry gas purification. By adding, it is possible to prevent carbon from being deposited on the desulfurization agent, the piping of the desulfurization apparatus 6 and the like in the dry gas purification process. Due to such a carbon deposition inhibiting effect, the desulfurization agent can remove the sulfur compound from the coal gasification gas g and purify the high calorie fuel gas f because the desulfurization action is not inhibited by the carbon deposition.

  Moreover, since the coal gasification gas g in which carbon is hard to precipitate is supplied to the dry gas purification equipment 4, it is possible to prevent the desulfurization apparatus 6 from being deteriorated or damaged by carbon precipitation, and the cost required for maintenance of the desulfurization apparatus 6 Can be reduced. Furthermore, it is not necessary to carry out special coating on the piping or the like of the desulfurization device 6, and the cost for the desulfurization device 6 can be further reduced. The desulfurization agent can be used for a long period of time because there is no need for carbon deposition and replacement, and the cost of the desulfurization agent can be reduced.

  Here, as shown in FIG. 2, it is also conceivable to individually add only carbon dioxide or only water vapor as a fluid for suppressing carbon deposition in the desulfurization apparatus 6.

  However, if the concentration of water vapor added to the coal gasification gas g is too high, the desulfurization performance of the desulfurizer 6 will be reduced. On the other hand, carbon dioxide has less effect of suppressing carbon deposition than water vapor.

  Thus, water vapor and carbon dioxide have a trade-off relationship between the effect of suppressing carbon deposition and the performance of the desulfurizing agent. Therefore, by using an exhaust gas containing carbon dioxide and water vapor as a fluid added to the coal gasification gas g as in the present invention, both the performance of the desulfurizing agent and the suppression of carbon deposition can be achieved.

  For example, if the amount of exhaust gas added is 10% of the coal gasification gas, the amount of carbon deposition in the desulfurization unit 6 is zero, and the desulfurization performance is maintained until the dimensionless time is close to “1”. can do.

  Further, the exhaust gas e compressed by the compressor 9 has a pressure and temperature suitable for adding to the coal gasification gas g. Therefore, it is not necessary to install a special compressor or the like for adjusting the pressure and temperature of the exhaust gas e in accordance with the pressure and temperature of the coal gasification gas g, and the fluid addition means can be configured at low cost. .

<Other embodiments>
In the embodiment described above, the compressor 9, the gas turbine 10, and the steam turbine 13 are arranged in a single shaft and include the generator 14. However, the compressor 9, the shaft of the gas turbine 10, and the shaft of the steam turbine 13 are arranged. May be arranged in parallel, and each may have a generator. Moreover, although the coal gasification power generation equipment 1 was provided with the gas turbine 10 and the steam turbine 13, it is not necessarily restricted to such an aspect. The steam turbine 13 is not essential as long as it includes at least the gas turbine 10.

<Description of the _{K B>}
The main reaction in which carbon is precipitated from coal gasification gas is considered to be the Boudouard reaction (Formula 1). As this reaction proceeds, two molecules of gas become one molecule, so the reaction system moves in the direction of decreasing the pressure. By this action, it can be predicted that this reaction is more likely to proceed as the pressure increases.
(1) 2CO → CO ₂ + C (solid)
The criterion for actually determining the ease of this reaction is the partial pressure ratio of carbon dioxide to carbon monoxide (P _CO2 / (P _CO ) ² ) that contributes to the Boudouard reaction, and is explained as follows from the viewpoint of chemical equilibrium. it can.
The progress of carbon deposition reaches equilibrium when a chemical equilibrium constant determined by (Equation 2), K _B (T), is reached at a certain temperature T, and no further reaction proceeds.
(2) K _B (T) = ρ _{CO 2} / (ρ _CO ) ²
K _B (T) is a pressure equilibrium constant (a constant determined by temperature T), and ρ _CO2 and ρ _CO are partial pressures of carbon dioxide and carbon monoxide at the time of chemical equilibrium. The relationship between the gas composition and the partial pressure is as in (Equation 3) and (Equation 4).
(3) ρ _CO2 = χ _CO2 × P
(4) ρ _CO = χ _CO × P
χ _CO2 and χ _CO are the molar fractions in the equilibrium of carbon dioxide gas and carbon monoxide gas in the coal gasification gas, and P is the pressure of the coal gasification gas.
By substituting (3) and (4) into (2), the relationship between the pressure equilibrium constant and the gas composition is obtained (formula 5 and formula 2).
_{(5) K B (T)} = χ CO2 × P / (χ CO × P) 2 = χ CO2 / (χ CO 2 × P)
The calculated division ratio _K B ₌ x CO2 at a certain gas composition / _{(x CO} ² × P) is,
(6) K _B (T)> K _B
When it is in the relationship, it means that x _CO2 / (x _CO ² × P) increases, that is, the Boudouard reaction proceeds. Conversely, (7) K _B (T) ≦ K _B in advance
The Boudouard reaction does not progress when Increasing the _{K B = x CO2 / (x} CO 2 × P) is seen to be a suppression of the Boudouard reaction.

  INDUSTRIAL APPLICABILITY The present invention can be used in a coal gasification power generation facility including a dry gas purification facility that generates coal gasification gas from coal and removes impurities in a dry manner.

DESCRIPTION OF SYMBOLS 1 Coal gasification power generation equipment 2 Coal gasification furnace 3 Heat exchanger 4 Dry-type gas purification equipment 5 Halide removal equipment 6 Desulfurization equipment 7 Combustor 8 Oxygen production equipment 9 Compressor 10 Gas turbine 11 Waste heat recovery boiler (HRSG)
DESCRIPTION OF SYMBOLS 12 Regenerative heat exchanger 13 Steam turbine 14 Generator 15 Condenser 16 Feed water heaters 17 and 19 Steam separators 18 and 20 Compressor 21 Pipe e Exhaust gas f Fuel gas g Coal gasification gas

Claims (3)

A coal gasifier that generates coal gasification gas by reaction of coal and oxidant;
A dry gas refining facility that removes impurities in the coal gasification gas by a dry method that operates while maintaining the temperature of the coal gasification gas generated in the coal gasification furnace above the dew point; and
Combustion means for burning the fuel gas obtained in the dry gas purification facility;
A gas turbine that obtains power by expanding combustion gas from the combustion means;
Fluid adding means for adding exhaust gas of the gas turbine containing carbon dioxide gas and water vapor as a fluid for suppressing carbon deposition in the dry gas purification facility to the coal gasification gas upstream of the dry gas purification facility; A coal gasification power generation facility characterized by comprising. In the coal gasification power generation facility according to claim 1,
The exhaust gas is defined by the following equation 1 where the molar fractions in the reaction conditions of carbon dioxide gas and carbon monoxide gas in the coal gasification gas are x _CO2 and x _CO respectively, the pressure of the coal gasification gas is P, and coal gasification power plant, characterized in that K _B is a fluid to vary the ratio of x _CO2 and x _CO to increase to be.
[Equation 1]
_{K B = x CO2 / (x} CO 2 × P) In the coal gasification power generation facility according to claim 1 or claim 2,
A coal gasification power generation facility comprising a steam turbine that obtains power by expanding steam obtained by recovering heat of exhaust gas of the gas turbine.

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