JP2007138900A - Electric power generation system combined with hydrogen production facility, electric power generating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power generation system combined with hydrogen production facility in which hydrogen production can be performed at low cost while increasing availability of the the whole system by sharing the use of gasification facility between the facilities of an electric power generation facility for generating electric power using gasification gas as fuel and hydrogen production facility for performing hydrogen production by separating hydrogen from the gasified gas. <P>SOLUTION: An electric power generation system includes a gasifying furnace 10 for gasifying raw materials such as coal, oil, biomass, a water supply apparatus 50 for supplying water to the raw materials or gasified gas, a heat exchanger 20 for cooling the gasified gas, a hydrogen separation apparatus 30 for separating hydrogen from the cooled gas, and an electric power generation facility 40 for generating electric power using a gas from which hydrogen has been separated as fuel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power generation system and a power generation method capable of generating power using gas obtained by gasifying raw materials such as coal, petroleum, and biomass and producing hydrogen from the gasified gas.

  2. Description of the Related Art Conventionally, as a thermal power generation system, a power generation system that generates power using gasified gas obtained by gasifying a raw material such as coal as fuel is known. In recent years, fuel cells using hydrogen as a fuel have attracted attention, and methods for producing hydrogen include methods for electrolyzing water and methods for producing hydrogen by reforming various fuel gases. Yes.

Regarding the power generation system and hydrogen production as described above, for example, in Patent Document 1, oxygen generated when hydrogen is produced by electrolysis of water is used as a gasifying agent for a gasification combined power generation system, and power generation is performed. A gasification combined power generation system is disclosed in which the electrical energy is used for hydrogen production. Further, in Patent Document 2, hydrogen is separated from a gas generated by thermal decomposition, and this hydrogen is used as a fuel to generate power, and the gas after separation of hydrogen is used as a heating fuel for thermal decomposition. An improved pyrolysis gasification system is disclosed.
Japanese Patent Laid-Open No. 10-17301 JP 2000-313892 A

  By the way, since the construction cost and running cost of a hydrogen production facility are high, there also exists a problem that hydrogen also becomes high cost. In particular, to produce high-purity hydrogen from the reformed gas, a great deal of cost is required for hydrogen separation and purification.

  On the other hand, in the power generation business, the facility capacity that can cope with the peak of power generation demand is secured. That is, there is a problem that the power equipment capacity always exceeds the power demand, and there is always an idle capacity where the power generation equipment cannot be effectively utilized. In general, the operation at a partial load has a problem that the efficiency is lower than that at the rated operation. In particular, the idle capacity is large during periods of low power generation demand such as at night, and it is an issue to improve the system utilization rate by effectively using the idle capacity.

  However, the system described in Patent Document 1 is intended to effectively use oxygen, which is a by-product of electrolysis, and it is said that it takes a great deal of cost to construct a hydrogen production facility. It does not solve the problem, and the problem that a great deal of cost is required for hydrogen separation and purification for recovering hydrogen has not been solved. Furthermore, no consideration is given to effectively utilizing the idle capacity of the power generation equipment.

  Further, even in the system described in Patent Document 2, it is not assumed that the idle capacity of the facility fluctuates due to load fluctuations according to time zones, and no effective utilization of the idle capacity of the facility is taken into consideration.

  The present invention has been made in view of the above points, and gas is used in both power generation equipment that generates power using gasified gas as fuel and hydrogen production equipment that produces hydrogen by separating hydrogen from the gasified gas. The purpose is to enable hydrogen production at low cost while improving the operating efficiency of the entire system by sharing the composting equipment.

  In order to achieve the above object, a power generation system according to the present invention includes means for gasifying raw materials such as coal, petroleum, and biomass, water supply means for supplying water to the raw materials or the gasified gas, According to a means for cooling the gasified gas, a means for separating hydrogen from the generated gas, a power generation facility that generates power using the gas after separating the hydrogen as fuel, and a power generation instruction amount for the power generation facility, And a moisture amount adjusting means for adjusting the amount of water supplied by the water supplying means.

  According to the present invention, hydrogen is separated from the gas gasified by the gasification means and the hydrogen-separated gas is generated as fuel, so that the gasification facility can be shared by the hydrogen production facility and the power generation facility. Therefore, hydrogen production can be performed at low cost while increasing the utilization rate of the entire system by using the idle capacity obtained by subtracting the power generation demand from the power generation capacity of the entire system for hydrogen production. Further, hydrogen that cannot be recovered as pure hydrogen among the produced hydrogen can be effectively used as a fuel for power generation while remaining in the gasification gas. Therefore, it is not necessary to forcibly increase the hydrogen recovery rate in the hydrogen separation / purification step, and thus the cost of the hydrogen separation means can be reduced.

  Moreover, in this invention, it is good also as providing the water quantity adjustment means which adjusts the water supply amount by the said water supply means according to the electric power generation instruction | indication quantity with respect to the said power generation equipment. In this way, when the power demand is small, the amount of hydrogen generated is increased by increasing the amount of water supplied, and the amount of hydrogen produced is increased accordingly, and the amount of combustion gas supplied to the power generation facility It is possible to reduce the power generation output due to the decrease in. In addition, when power demand is large, the amount of hydrogen generation is reduced by reducing the water supply amount, and the amount of hydrogen produced is increased correspondingly, and the amount of combustion gas supplied to the power generation facilities is increased. The output can be increased. That is, by adjusting the water supply amount according to the power demand (that is, the power generation instruction amount for the power generation facility), the power generation output of the power generation facility can be adjusted, and the fluctuation can be absorbed by the change in the hydrogen production amount. .

  Moreover, it is good also as supplying water vapor | steam instead of supplying water.

  Moreover, it is good also as providing the hydrogen amount adjustment means which adjusts the hydrogen separation amount by the said hydrogen separation means according to the electric power generation instruction | indication quantity with respect to the said power generation equipment. In this way, when the power demand is small, the amount of hydrogen separation can be increased to increase the amount of hydrogen produced, and the power generation output can be decreased by reducing the amount of combustion gas supplied to the power generation equipment. it can. Further, when the power demand is large, it is possible to reduce the amount of hydrogen produced by reducing the amount of hydrogen separation and to increase the power generation output by increasing the amount of combustion gas supplied to the power generation equipment. That is, by adjusting the hydrogen separation amount according to the power demand (that is, the power generation instruction amount for the power generation facility), the power generation output of the power generation facility can be adjusted, and the fluctuation can be absorbed by the change in the hydrogen production amount. .

  According to the present invention, the gasification facility is shared by both the power generation facility that generates power using the gasification gas as fuel and the hydrogen production facility that performs hydrogen production by separating hydrogen from the gasification gas. It becomes possible to produce hydrogen at a low cost while improving the overall utilization rate.

  FIG. 1 is an overall configuration diagram of a hydrogen production facility combined power generation system (hereinafter simply referred to as a power generation system) 1 according to an embodiment of the present invention. As shown in the figure, the power generation system 1 of the present embodiment includes a gasification furnace 10, a heat exchanger 20, a hydrogen separator 30, a power generation facility 40, a water supply device 50, a hydrogen storage 60, and a controller 70. Yes.

The gasification furnace 10 is fed with raw materials such as coal, petroleum, biomass, etc., and these raw materials are pyrolyzed in the gasification furnace 10 to become volatile components and char (C). Char burns. These reactions are as shown in the following reaction formulas 1-2.
Coal → Volatile component + Char (C) (Reaction formula 1)
Volatile component → CO ₂ + H ₂ O (Reaction Formula 2)

Further, the char (C) remaining without being burned reacts with the gas in the gasification furnace 10 using the combustion heat generated by the combustion of volatile components or the like as shown in the following reaction formulas 3 to 5. Gasification to produce CO, CH ₄ , H _{2 and the} like.
Char (C) + CO ₂ → 2CO (Reaction Formula 3)
Char (C) + 2H ₂ → CH ₄ (Scheme 4)
Char (C) + H ₂ O → H ₂ + CO (Scheme 5)

Further, water is supplied from the water supply device 50 to the gasification furnace 10. The supplied water reacts with the gasification gas and char (C) in the gasification furnace 10 as shown in the following reaction formulas 5 to 7, thereby generating hydrogen.
Char (C) + H ₂ O → CO + H ₂ (Scheme 6)
CH ₄ + H ₂ O → CO + 3H ₂ (Scheme 7)
CO + H ₂ O → CO ₂ + H ₂ (Scheme 8)

  The amount of water supplied by the water supply device 50 is controlled by the controller 70. As can be seen from the reaction formulas 6 to 8, the amount of hydrogen generated is an amount corresponding to the amount of water supplied to the gasifier 10. Therefore, the amount of generated hydrogen can be adjusted by controlling the amount of water supplied by the controller 70. Note that a catalyst may be attached to the gasification furnace 10 in order to promote the reaction in the gasification furnace 10.

Pyrolysis gas such as CO, CH ₄ and H ₂ generated in the gasification furnace 10 is supplied to the heat exchanger 20 as a cooling means and cooled by the heat exchanger 20. In addition, you may perform the supply of the water by the above-mentioned water supply apparatus 50 in the gas supply path from the gasification furnace 10 to the heat exchanger 20. FIG.

The pyrolysis gas cooled by the heat exchanger 20 is sent to the hydrogen separator 30 where hydrogen is separated. The amount of hydrogen separated by the hydrogen separator 30 is controlled by the controller 70. Even if hydrogen remains in the pyrolysis gas after hydrogen separation, the hydrogen can be effectively used as fuel for the power generation facility 40 together with CO, CH _{4 and the} like. Therefore, the cost of the hydrogen separator 30 can be reduced.

  The hydrogen separated by the hydrogen separator 30 is compressed or liquefied and stored in the hydrogen storage tank 60. A part of hydrogen can also be used as a refrigerant for a hydrogen-cooled generator. On the other hand, the pyrolysis gas from which hydrogen has been separated is sent to the power generation facility 40 where it is burned as fuel for power generation. The power generation facility 40 may be any of combined power generation (combined cycle), gas turbine power generation (open cycle), and steam power generation. The electric power generated by the power generation facility 40 is transmitted to the system via the power transmission facility 44.

  The controller 70 is given a power generation instruction amount for the power generation facility 40, and controls the water supply amount by the water supply device 50 or the hydrogen separation amount by the hydrogen separation device 30 as described above based on this power generation instruction amount.

  That is, as the amount of water supplied by the water supply device 50 increases, the amount of generated hydrogen increases, the amount of combustion gas other than hydrogen decreases, and the amount of power generated by the power generation facility 40 also decreases. Therefore, for example, the relationship between the water supply amount and the power generation amount (FIG. 2) when the hydrogen separation amount by the hydrogen separation device 30 is a constant amount is grasped in advance and stored in the controller 70. According to the relationship, the water supply amount is controlled so that a power generation amount corresponding to the power generation instruction amount is obtained.

  Further, as the amount of hydrogen separated by the hydrogen separator 30 increases, the amount of combustion gas supplied to the power generation facility 40 decreases and the amount of power generated by the power generation facility 40 also decreases. Therefore, for example, when the water supply amount by the water supply device 50 is a constant amount, the relationship (FIG. 3) between the hydrogen separation amount and the power generation amount is grasped in advance and stored in the controller 70. In accordance with this relationship, the hydrogen separation amount is controlled so that a power generation amount corresponding to the power generation instruction amount is obtained.

  As described above, the controller 70 controls the water supply amount by the water supply device 50 or the hydrogen separation amount by the hydrogen separation device 30, whereby the power generation amount can be adjusted according to the power generation instruction amount. Accordingly, hydrogen can be produced while the power generation system 1 is stably operated with the raw material input amount to the gasifier 10 kept constant, and fluctuations in power demand can be absorbed by changes in the hydrogen production amount. it can. As a result, the operating rate of the entire system can be improved, and hydrogen can be produced at low cost.

  Hereinafter, an operation example of the power generation system 1 will be described in the case where the power generation amount is adjusted based on the water supply amount.

(1) Operation example 1
When the power demand during the daytime period is increasing, the amount of water supplied from the water supply device 50 to the gasifier 10 is decreased by a command from the controller 70. As a result, the amount of hydrogen in the pyrolysis gas produced in the gasifier decreases, and the amount of pyrolysis gas other than hydrogen increases accordingly. In the power generation facility 40, the amount of power generation increases as the amount of pyrolysis gas supplied as fuel after hydrogen separation increases. Thereby, when the electric power demand in daytime hours etc. is increasing, the amount of hydrogen production can be reduced and the electric power corresponding to the electric power demand can be generated.

(2) Operation example 2
When the power demand during the night time period is decreasing, the amount of water supplied from the water supply device 50 to the gasifier 10 is increased by a command from the controller 70. If it does so, the quantity of hydrogen will increase in the pyrolysis gas produced | generated within a gasification furnace, and the quantity of pyrolysis gases other than hydrogen will reduce. In the power generation facility 40, the amount of power generation also decreases due to a decrease in the amount of pyrolysis gas supplied as fuel after hydrogen separation. Thereby, when the electric power demand, such as a night time zone, is decreasing, hydrogen production can be increased. That is, since the decrease in electric power demand can be used for hydrogen production, it is possible to produce hydrogen at a low cost without making a large capital investment.

1 is an overall configuration diagram of a coal gasification gas power generation facility combined with hydrogen production that is an embodiment of the present invention. It is a figure which shows the relationship between the amount of water supply, and the electric power generation amount when the amount of hydrogen separation by a hydrogen separator is made into a fixed amount. It is a figure which shows the relationship between the amount of hydrogen separation, and the electric power generation amount when the water supply amount by a water supply apparatus is made into a fixed amount.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen production facility combined use power generation system 10 Gasification furnace 20 Heat exchanger 30 Hydrogen separator 40 Power generation facility 44 Power transmission facility 50 Water supply device 60 Hydrogen storage tank 70 Controller

Claims (6)

Gasification means for gasifying raw materials such as coal, oil, and biomass;
Water supply means for supplying water to the raw material or the gasified gas;
Cooling means for cooling the gasified gas;
Hydrogen separation means for separating hydrogen from the cooled gas;
And a power generation facility that generates power using the gas after separating the hydrogen as a fuel. The hydrogen production facility combined use power generation system according to claim 1, further comprising water amount adjusting means for adjusting a water supply amount by the water supply means according to a power generation instruction amount for the power generation facility. . The hydrogen production facility combined use power generation system according to claim 1 or 2, further comprising a hydrogen amount adjusting means for adjusting a hydrogen separation amount by the hydrogen separation means according to a power generation instruction amount for the power generation facility. Combined power generation system. Gasifying raw materials such as coal, oil and biomass;
A water supply step for supplying water to the raw material or the gasified gas;
Cooling the gasified gas;
Separating hydrogen from the generated gas;
And a step of generating electricity using the gas after separating the hydrogen as a fuel. The power generation method according to claim 4, wherein
A power generation method comprising: an adjustment step of adjusting a water supply amount in the water supply step in accordance with an instruction power generation amount for the power generation facility. The power generation method according to claim 4 or 5,
A power generation method comprising: an adjustment step of adjusting a hydrogen recovery amount in the hydrogen separation step according to an instruction power generation amount for the power generation facility.

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