JP2003120441A - Gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain or use hydrocarbon series fuel and a raw material such as water vapor to be supplied to a fuel reformer under an appropriate condition, in a gas engine for supplying the reformed fuel obtained by reforming the hydrocarbon series fuel with a fuel reformer, to a combustion chamber. SOLUTION: A higher-order desulfurizing apparatus 53 capable of desulfurizing a sulphur component included in methane gas (hydrocarbon series fuel) to a ppb level and supplying it to the fuel reformer 51, is provided for a fuel supply system 5. A hydro-desulfurizing apparatus 56 which removes the sulphur component included in methane gas to a ppm level by means of the hydro- desulfurizing, is provided on the upstream side of the higher-order desulfurizing apparatus 53.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine for reforming a hydrocarbon fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber. In particular, the invention is
The present invention relates to a pretreatment technology for a raw material supplied to a fuel reformer.

[0002]

2. Description of the Related Art Conventionally, as one form of a gas engine, a hydrocarbon-based fuel (C _m H _n ) is reformed by a fuel reformer to obtain a fuel having a large calorific value, thereby improving the thermal efficiency of the engine. It is known to improve the quality.

FIG. 4 is a block diagram showing a schematic configuration of a power generation system for generating power by this type of gas engine. As shown in this figure, in the present gas engine, an output shaft a1 extending from the engine body a is connected to a generator b, and the rotational driving force of the output shaft a1 causes the generator b to generate electric power. ing.

The intake system of the gas engine is composed of an air supply system and a fuel supply system, and a mixture of air supplied from the air supply system and fuel supplied from the fuel supply system enters the combustion chamber. The engine body a is supplied and driven.

The air supply system is a supercharger (compressor) c.
And an intercooler d. That is, after the air is compressed by the supercharger c, the air is cooled by the intercooler d, so that high-density air can be supplied toward the combustion chamber. The supercharger c is directly connected to the output shaft f1 of the turbine f provided in the exhaust pipe e through which the exhaust gas flows, and receives the rotational output of the turbine f to compress the air.

On the other hand, the fuel supply system includes a fuel reformer g and exhaust heat.
A boiler h, a hydrodesulfurization device i, and a tank j are provided. This
In the fuel supply system of_mH_n) And water vapor
(H ₂O) and endothermic reaction in the fuel reformer g
Therefore, the fuel composition is changed, which causes the original hydrocarbon
So that a fuel with a larger calorific value than the base fuel can be obtained
ing. The heat energy required for this endothermic reaction is exhausted.
It is adapted to be obtained from the exhaust gas flowing through the pipe e.

Specifically, first, since the hydrocarbon-based fuel contains a sulfur content, this sulfur content is removed by the hydrodesulfurization unit i, and the hydrocarbon-based fuel after the sulfur content is removed is It is supplied to the fuel reformer g. The catalyst of the fuel reformer g (metal (Rh, Ru, Ni, Ir, Pd, Pt, R
e, Co, Fe), alkali carbonates (K ₂ CO ₃ ), basic oxides (MgO, CaO, K ₂ O), mineral substances such as coal (FeS ₂ ), and sulfur (digestion gas or biogas). There is a risk of poisoning due to hydrogen sulfide in the gas, the odorant of city gas, the sulfur content of petroleum-based fuels, etc. In order to avoid this, the hydrodesulfurization unit i and the water desulfurization unit i are treated with water. A hydrogen cylinder k for supplying hydrogen for performing the desulfurization is required. On the other hand, in the exhaust heat boiler h, steam is generated by utilizing the heat quantity of the exhaust gas flowing through the exhaust pipe e, and this steam is supplied to the fuel reformer g. Further, the fuel reformer g is provided with a heat exchanger (not shown) for acquiring the heat energy of the exhaust gas. As a result, the following endothermic reaction takes place inside the fuel reformer g.

C _m H _n + mH ₂ O → mCO + (n / 2 + m) H ₂ (1) When the hydrocarbon fuel is methane (m = 1, n = 4), the following endothermic reaction occurs.

CH ₄ + H ₂ O → CO + 3H ₂ (2) When such a reaction is performed, the calorific value of the fuel after reforming is significantly higher than that of the original hydrocarbon fuel (for example, 25
%), Whereby a fuel capable of improving power generation efficiency (power generator output / supply fuel C _m H _n ) can be obtained.

The reformed fuel is once stored in the tank j, and after removing excess residual H ₂ O by a dehumidifier (not shown) built in the tank j, it is supplied from the air supply system. The mixed air is supplied to the combustion chamber.

[0011]

The conventional gas engine described above has the following problems, and these problems greatly hinder the practical use of the gas engine. (1) In the hydrodesulfurization apparatus i, the sulfur content could not be sufficiently removed. Specifically, in order to completely prevent poisoning of the catalyst of the fuel reformer g, the sulfur content (generally called slip sulfur) contained in the hydrocarbon fuel supplied to the fuel reformer g. Needs to be kept low to the ppb level, but in the hydrodesulfurization unit i, 0.1 to 1 ppm
Slip sulfur can only be reduced to levels. Therefore, with the conventional configuration, it is impossible to completely prevent poisoning of the catalyst of the fuel reformer g. (2) It is highly possible that impurities such as halogen and arsenic are contained in the water supplied to the exhaust heat boiler h, and the impurities are mixed in the steam supplied to the fuel reformer g. If so, there was a possibility that the catalyst of the fuel reformer g was poisoned.

The present invention has been made in view of the above points, and an object of the present invention is to reform a hydrocarbon fuel in a fuel reformer, and then feed the reformed fuel to a combustion chamber. It is to make hydrocarbon-based fuel and raw materials such as steam to be supplied to the fuel reformer available or suitable for the gas engine to be supplied to the fuel engine.

[0013]

Means for Solving the Problems-Outline of the Invention-In order to achieve the above object, the present invention pre-treats a hydrocarbon-based fuel or a raw material such as steam to be supplied to a fuel reformer in advance. By doing so, the utility of the gas engine is enhanced.

-Solution means-Specifically, the first solution means is premised on a gas engine which reforms a hydrocarbon fuel by a fuel reformer and supplies the reformed fuel to a combustion chamber. To do. This gas engine is equipped with a high-order desulfurization device that can desulfurize the sulfur content contained in hydrocarbon fuels to the ppb level.

By this specific matter, poisoning of the catalyst of the fuel reformer is almost eliminated, and the life of the catalyst can be extended. In addition, since a high-order desulfurization apparatus can generally perform high-performance desulfurization operation even in an environment at room temperature, the desulfurization operation has good startability. As a result, it is possible to supply the hydrocarbon-based fuel with slip sulfur reduced to the level of 1 ppb to the fuel reformer substantially at the same time when the gas engine is started, and the engine startability is improved.

A second solving means is the above first solving means, wherein a hydrodesulfurization device for removing the sulfur content contained in the hydrocarbon fuel by hydrodesulfurization is provided upstream of the higher-order desulfurization device. ing. According to this configuration, the hydrocarbon-based fuel supplied to the higher-order desulfurization device is one in which the sulfur content has been previously removed to the level of 0.1 to 1 ppm by the hydrodesulfurization device. The amount of sulfur introduced can be extremely reduced. As a result, it is possible to improve the efficiency of the sulfur removal operation in the high-order desulfurization device and extend the life of the high-order desulfurization device. Further, it is possible to reduce the frequency of maintenance work of the high-order desulfurization device.

A third means for solving the problem is to construct a fuel reformer so as to reform the hydrocarbon fuel by causing an endothermic reaction between the hydrocarbon fuel and steam. Then, a steam generating means for generating steam is provided, and an operating state of supplying the hydrocarbon fuel and steam to the fuel reformer,
The configuration is such that it can switch between a catalyst performance recovery processing state in which only steam is supplied to the fuel reformer. That is,
In the above operating state, the gas engine is operated due to the endothermic reaction between the hydrocarbon fuel and water vapor. On the other hand, in the catalyst performance recovery processing state, only steam is supplied to the fuel reformer, and even if the catalyst in the fuel reformer is poisoned by the sulfur content in the hydrocarbon-based fuel, this steam will still be used. The performance of the poisoned catalyst can be restored, which allows the catalyst to be regenerated. That is, the catalyst can be regenerated by using the steam that is the raw material supplied to the fuel reformer.

In a fourth solution means, in the third solution means, a ratio of steam to hydrocarbon fuel (steam) supplied in an operating state in which the hydrocarbon fuel and steam are supplied to the fuel reformer. Ratio) is set to 2.5 or more and 3.0 or less. By setting the steam ratio in this range, it is possible to effectively prevent carbon deposition on the catalyst inside the fuel reformer, and to continue highly efficient endothermic reaction for a long period of time. Becomes

In the fifth solution means, a heat exchanger for preheating the raw material by exchanging heat between the reformed fuel discharged from the fuel reformer and the raw material introduced into the fuel reformer is provided. I am preparing. As a result, the heat energy in the reformed fuel can be recovered, and the amount of exhaust heat recovered can be increased. In addition, the endothermic reaction can be promoted by performing pretreatment such as preheating on the raw material introduced into the fuel reformer.

In the sixth solution means, the water contained in the post-reformation fuel discharged from the fuel reformer and the raw material introduced into the fuel reformer are heat-exchanged to perform the post-reformation fuel. A heat exchanger for condensing the water contained therein and a water return path for returning the water condensed in the heat exchanger as a part of the raw material for fuel reforming are provided. As a result, the water contained in the reformed fuel can be effectively used without being discarded, and the running cost of the water supply facility can be reduced. Further, since the pretreatment such as returning the condensed water to the fuel supply system is performed, the amount of raw material required per unit time of the gas engine can be reduced.

The seventh solution means is provided with steam generating means for generating steam to be supplied to the fuel reformer, and pure water generating means for removing impurities contained in water supplied to the steam generating means. I am letting you.

As a kind of the pure water producing means, the eighth solving means uses a halogen removing device for removing halogen contained in water. Further, in the ninth solving means, an arsenic removing device for removing arsenic contained in water is used.

By these specific matters, it is possible to prevent impurities such as halogen and arsenic from being included in the water vapor supplied to the fuel reformer, thereby preventing poisoning of the catalyst of the fuel reformer 51. can do. As a result, the life of the fuel reformer and the steam generator can be extended, and the cost can be reduced by eliminating the need for the pure water tank.

Further, the gas engine may be constructed by combining a plurality of constructions of the above-mentioned means.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, methane gas (C
A case where the present invention is applied to a gas engine in which H ₄ ) is reformed by a fuel reformer to obtain a fuel having a large calorific value will be described. In addition, the gas engine according to the present embodiment uses its output for power generation.

(First Embodiment) First, the first embodiment will be described.

-Description of Configuration of Gas Engine- FIG. 1 is a block diagram showing a schematic configuration of a power generation system for generating power by the gas engine according to the present embodiment. As shown in this figure, the gas engine 1 includes an engine body 2
An output shaft 21 extending from the output shaft 21 is connected to the generator 3, and the rotational driving force of the output shaft 21 causes the generator 3 to generate electric power.

The intake system of the gas engine 1 comprises an air supply system 4 and a fuel supply system 5, and the air supply system 4
A mixture of air supplied from the engine and fuel supplied from the fuel supply system 5 is supplied to a combustion chamber (not shown) of the engine body 2 to drive the engine body 2. Hereinafter, the air supply system 4 and the fuel supply system 5 will be described.

The air supply system 4 is a supercharger (compressor).
41 and an intercooler 42. That is, after the air is compressed by the supercharger 41 and the air is cooled by the intercooler 42, high density air can be supplied toward the combustion chamber. The supercharger 41 is directly connected to the output shaft 62 of the turbine 61 provided in the exhaust pipe 6 through which the exhaust gas flows, and receives the rotational output of the turbine 61 to compress the air.

On the other hand, the fuel supply system 5 includes a fuel reformer 51,
It is provided with an exhaust heat boiler 52 as a steam generating means, a high-order desulfurization device 53 and a tank 55 which are features of this embodiment. In the fuel supply system 5, methane gas (CH ₄ ) which is a hydrocarbon fuel and steam (H ₂ O) are supplied to the fuel reformer 51.
Change the fuel composition by causing an endothermic reaction in the
This makes it possible to obtain a fuel having a larger calorific value than the original methane gas. The heat energy required for this endothermic reaction is obtained from the exhaust gas flowing through the exhaust pipe 6. Hereinafter, each element constituting the fuel supply system 5 will be described.

Water is supplied from the outside to the exhaust heat boiler 52, and the water is stored inside.
By exchanging heat with the exhaust gas flowing through the water, water is evaporated and steam is generated. The exhaust heat boiler 52 and the fuel reformer 51 are connected by a steam supply pipe 71, and the steam generated in the exhaust heat boiler 52 can be supplied into the fuel reformer 51. Further, the steam supply pipe 71 is provided with an electric valve 71a whose opening can be adjusted.

The high-order desulfurization device 53 is for removing the sulfur content contained in the methane gas. That is,
Catalyst of the fuel reformer 51 (metal (Rh, Ru, Ni, I
r, Pd, Pt, Re, Co, Fe), alkali carbonate (K ₂ CO ₃ ), basic oxide (MgO, CaO, K)
₂ O), minerals such as coal (FeS ₂ ) and the like may be poisoned by sulfur, and in order to avoid this, the high-order desulfurization device 53 is installed. In addition, this high-order desulfurization device 5
3, a pre-reforming fuel supply pipe 72 for supplying methane gas and a desulfurized fuel supply pipe 73 for supplying desulfurized fuel to the fuel reformer 51 are connected.

The high-order desulfurization device 53 will be described in detail below. The high-order desulfurization device 53 is capable of reducing slip sulfur to a level of 1 ppb, and is capable of performing high-performance desulfurization operation even in an environment at room temperature. The principle of the desulfurization is such that the active metal on the metal oxide can also decompose organic sulfur such as thiophene to perform desulfurization.

The fuel reformer 51 is configured to cause an endothermic reaction between steam and methane gas to perform a fuel reforming operation. That is, an endothermic reaction is performed between the steam supplied from the steam supply pipe 71 and the methane gas supplied from the desulfurized fuel supply pipe 73. Further, inside the fuel reformer 51, a heat exchanger (not shown) for obtaining the heat energy of the exhaust gas is provided. As a result, the following endothermic reaction is performed inside the fuel reformer 51 under an environment of a predetermined temperature (exhaust gas temperature of about 600 ° C., for example).

CH ₄ + H ₂ O → CO + 3H ₂ (2) By carrying out such a reaction, the calorific value of the fuel after reforming is significantly higher than that of the original methane gas, which causes power generation efficiency (power generation). It is possible to obtain fuel that can improve the machine output / fuel supply).

The fuel reformer 51 and the tank 55 are for supplying the hydrogen gas and other fuels (CO, CH ₄ , H ₂ O) obtained by the endothermic reaction to the tank 55. Are connected by a fuel supply pipe 76. The fuel supply pipe 76 has an electric valve 76 with an adjustable opening.
a is provided.

The tank 55, to which the fuel is supplied by the fuel supply pipe 76, temporarily stores the fuel, and a dehumidifier (not shown) built in the tank 55 stores excess residual H ₂
After removing O, the reformed fuel is supplied with the reformed fuel supply pipe 7
It is designed to be mixed with air via 8 and supplied to the combustion chamber.

The gas engine 1 is also provided with a controller 8 for controlling each part. The controller 8 is connected to a plurality of sensors 81, 82, 83, receives detection signals from the sensors 81, 82, 83, and controls the opening degree of each of the motor-operated valves 71a, 76a. There is. The sensors include a load sensor 81 that detects the load of the generator 3 and the engine body 2
Knocking sensor 8 for measuring the knocking strength of a vehicle
2. A hydrogen concentration sensor 83 for measuring the hydrogen component concentration in the fuel supplied from the tank 55 to the engine body 2 (the hydrogen component concentration in the reformed fuel supply pipe 78) is provided. The above is the configuration description of the gas engine 1.

-Description of Operation of Gas Engine 1- Next, the operation of the gas engine 1 configured as described above will be described.

First, with the electric valve 71a of the steam supply pipe 71 open, the water inside the exhaust heat boiler 52 is heated by the exhaust gas flowing through the exhaust pipe 6 to become steam.
Then, this steam is sequentially supplied to the fuel reformer 51 through the steam supply pipe 71.

At the same time, methane gas is supplied to the high-order desulfurization device 53 by the pre-reforming fuel supply pipe 72, and the desulfurization operation is performed here. In the desulfurization operation in the high-order desulfurization device 53, as described above, slip sulfur can be reduced to the level of 1 ppb in a room temperature environment. Therefore, almost no sulfur is present in the methane gas supplied from the higher-order desulfurization device 53 to the fuel reformer 51 by the desulfurization fuel supply pipe 73, and the catalyst of the fuel reformer 51 is almost not poisoned. Disappear.

In this way, the above endothermic reaction is carried out with the steam and methane gas supplied to the fuel reformer 51. In addition to steam and methane gas, the fuel reformer 51 also includes air, oxygen (O ₂ ), carbon dioxide (C
O ₂ ) is also supplied. During the endothermic reaction,
The heat energy of the exhaust gas is acquired by the heat exchanger in the fuel reformer 51, whereby an endothermic reaction is performed inside the fuel reformer 51 under an environment of a predetermined temperature, and carbon monoxide (CO) is generated. And hydrogen gas (H ₂ ) are generated. At this time, unreformed steam (H ₂ O) and methane gas (CH ₄ ) are also present inside the fuel reformer 51.

When fuel is supplied to the engine body 2,
The electric valve 76a of the fuel supply pipe 76 is opened. As a result, the hydrogen gas, methane gas, carbon monoxide, and steam in the fuel reformer 51 are transferred to the tank 5 through the fuel supply pipe 76.
5 is supplied. In the tank 55, each fuel is temporarily stored, and excess deionized H ₂ O is removed by a dehumidifier (not shown) built in the tank 55. Then, the reformed fuel is mixed with the air supplied from the air supply system 4 through the reformed fuel supply pipe 78 and is supplied to the combustion chamber of the engine body 2.

As a result, the engine body 2 is driven, and the generator 3 is driven as the output shaft 21 is rotationally driven to generate electricity.

-Effects of Embodiment-As described above, in this embodiment, the sulfur content (slip sulfur) in the methane gas is 1 ppb due to the high-order desulfurization device 53.
The methane gas reduced to the level is supplied to the fuel reformer 51. Therefore, poisoning of the catalyst of the fuel reformer 51 is almost eliminated, and the life of the catalyst can be extended. Further, since the high-order desulfurization device 53 can perform high-performance desulfurization operation even in an environment at room temperature, the desulfurization operation has good startability. That is, it is possible to supply the methane gas in which the slip sulfur has been reduced to the level of 1 ppb to the fuel reformer 51 almost at the same time when the gas engine 1 is started.

(Second Embodiment) Next, a second embodiment will be described. The present embodiment is a modification of the configuration for removing the sulfur content contained in the methane gas, and the other configurations are similar to those of the first embodiment described above. Therefore, only the structure for removing the sulfur content will be described here.

As shown in FIG. 2, the fuel supply system 5 of the gas engine 1 according to this embodiment is provided with a hydrodesulfurization device 56 and a high-order desulfurization device 53. Below, each desulfurization device 5
3, 56 will be described.

The hydrodesulfurization unit 56 is capable of removing the sulfur content contained in methane gas to a level of 0.1 to 1 ppm. Further, in this hydrodesulfurization apparatus 56, desulfurization operation by hydrodesulfurization is performed, so that a hydrogen tank (not shown) for supplying hydrogen is connected. Further, in the hydrodesulfurization device 56, the pre-reforming fuel supply pipe 72 for supplying methane gas and the fuel after desulfurization are advanced desulfurization device 53.
A supply pipe 79 for supplying the electric power is supplied. Also,
The hydrodesulfurization device 56 performs desulfurization operation in a high temperature environment, and its thermal energy is obtained by the exhaust gas flowing through the exhaust pipe 6. That is, the hydrodesulfurization device 56 is provided with a heat exchanger (not shown) for taking in the heat of the exhaust gas.

On the other hand, the high-order desulfurization device 53 has the above-mentioned first
It has the same configuration as that of the embodiment, and is connected to the discharge side of the hydrodesulfurization device 56 by a supply pipe 79. That is, the methane gas from which the sulfur content has been removed to the level of 0.1 to 1 ppm in the hydrodesulfurization device 56 is further desulfurized by the high-order desulfurization device 53, and the slip sulfur is reduced to 1 ppb level or less. .

According to the configuration of this embodiment, the high-order desulfurization device 53
The sulfur content of the methane gas supplied to the above is desulfurized in advance to a level of 0.1 to 1 ppm by the hydrodesulfurization device 56. Therefore, the amount of sulfur introduced into the high-order desulfurization device 53 should be extremely reduced. You can Therefore, the burden of sulfur removal on the high-order desulfurization device 53 can be significantly reduced, and the efficiency of sulfur removal operation on the high-order desulfurization device 53 can be improved and the life of the high-order desulfurization device 53 can be extended. Can be planned.
In addition, it is possible to reduce the frequency of maintenance work of the high-order desulfurization device 53 and reduce maintenance costs.

(Third Embodiment) Next, a third embodiment will be described. This embodiment is a modification of the above-described first embodiment. Therefore, only the differences from the first embodiment will be described here.

As shown in FIG. 3, in the fuel supply system 5 of the gas engine 1 according to the present embodiment, in addition to the components of the fuel supply system 5 of the gas engine 1 according to the first embodiment, the heat exchanger 57. Also, a pure water device 58 as a pure water generating means is provided.

The heat exchanger 57 has the reformed fuel (reformed gas) derived from the fuel reformer 51 and methane gas (desulfurized by the high-order desulfurization device 53) supplied to the fuel reformer 51. After that, it exchanges heat with the methane gas). As a result, the methane gas supplied to the fuel reformer 51 can be preheated. The heat exchanger 57 also exchanges heat between the reformed fuel (reformed gas) derived from the fuel reformer 51 and the pure water supplied from the pure water device 58 to the exhaust heat boiler 52. Is to be done. Thereby, the pure water supplied to the exhaust heat boiler 52 can be preheated. As described above, by adopting the configuration in which the methane gas and the pure water that are the raw materials of the gas engine 1 are preheated, the thermal energy in the reformed fuel can be recovered, and the exhaust heat recovery amount can be increased. .

Further, the pure water device 58 is provided with a water supply pipe 58a.
Is connected to the exhaust heat boiler 52 by the heat exchanger 5
Reference numeral 7 is a water return pipe 57a that constitutes the water return path in the present invention.
Is connected to this water supply pipe 58a. That is, the water formed by condensing the water contained in the reformed fuel by the heat exchanger 57 can be used as the raw material of the steam generated in the exhaust heat boiler 52. Therefore, the water contained in the reformed fuel can be effectively used without being discarded, and the running cost of the pure water supply facility can be reduced.

On the other hand, the pure water device 58 is supplied with, for example, tap water, generates pure water from the tap water, and supplies the pure water to the exhaust heat boiler 52 through the water supply pipe 58a. That is, high purity pure water is generated by removing impurities such as halogen and arsenic contained in tap water. Specific examples of the pure water device 58 include a distillation type pure water device, a cartridge type pure water device,
An ion exchange type pure water device, an electric regeneration type pure water device, a device by a continuous ion exchange method (EDI) applying the electrodialysis principle, and the like are listed.

In particular, as a method for removing halogen, an activated carbon filtration method, a microfiltration method (using an MF membrane (microfilter) or the like), an ultrafiltration method (using a UF membrane (ultrafilter) or the like), reverse osmosis At least one of the membrane methods (by RO membrane (reverse osmosis) etc.) is selected. On the other hand, as a method for removing arsenic, coagulation sedimentation method (precipitation method), ion exchange method, activated alumina method, low pressure reverse osmosis membrane method, reverse osmosis membrane method (pressure is applied in the direction opposite to the osmotic pressure) Method) and at least one of the ADI methods is selected.

For example, in the above sedimentation method, raw water (tap water)
An oxidant and a coagulant are injected into the mixture, which are mixed by a mixer and passed through a UD filter. At this time, when raw water passes through the filter layer of the filter, agglomerated flocs incorporating arsenic are supplemented. This treated water is filtered more rapidly to remove residual arsenic and suspended matter.

In the activated alumina method, the oxidizing agent and the raw water into which the acid for adjusting the pH has been mixed are mixed by a mixer and the mixture is flowed into the activated alumina adsorption tower. Then, this treated water is readjusted in the purification pond to raise the pH value to near neutral. Furthermore, suspended matter, iron, manganese, etc. are removed by a filter.

Pure water here generally means water containing impurities at a concentration of the order of ppm (mg / l). Moreover, the high-performance pure water device 58 can also generate ultrapure water. The ultrapure water generally means water containing impurities at a concentration on the order of ppb (μg / l).

By using pure water as the water supplied to the exhaust heat boiler 52 in this manner, it is possible to avoid inclusion of impurities such as halogen and arsenic in the steam supplied to the fuel reformer 51. In this way, poisoning of the catalyst of the fuel reformer 51 can be prevented. As a result, the life of the fuel reformer 51 and the exhaust heat boiler 52 is extended,
The cost can be reduced by eliminating the need for a pure water tank.

Further, in the present embodiment, the desulfurized fuel supply pipe 73 for supplying the fuel from the high-order desulfurization device 53 to the fuel reformer 51 is also provided with the electric valve 73a. During normal operation, both the motor-operated valve 71a of the steam supply pipe 71 and the motor-operated valve 73a of the desulfurized fuel supply pipe 73 are opened, and methane gas and steam are supplied to the fuel reformer 51 to generate gas accompanying the endothermic reaction. The engine 1 is operated. On the other hand, when the catalyst of the fuel reformer 51 is poisoned or when the power generation load is small, the electric valve 71a of the steam supply pipe 71 is opened and the electric valve 73a of the desulfurized fuel supply pipe 73 is closed. As a result, only the steam is supplied to the fuel reformer 51 (the catalyst performance recovery processing state in the present invention). By supplying only this steam, the fuel reformer 5
The performance of the poisoned catalyst of No. 1 is restored, whereby the catalyst can be regenerated. This configuration has the above-mentioned first and second
It is also applicable to the embodiment.

In the normal operation in which methane gas and steam are supplied to the fuel reformer 51, the ratio of steam to methane gas (called steam ratio) is 2.
It is preferably set to 5 or more and 3.0 or less. By setting the steam ratio in this range, it is possible to effectively prevent carbon from being deposited on the catalyst inside the fuel reformer 51, and to continue a highly efficient endothermic reaction for a long period of time. It will be possible.

Further, as the pure water device 58, a device for removing impurities other than halogen and arsenic may be adopted.

In the third embodiment, the hydrodesulfurization device 56 may be provided upstream of the higher-order desulfurization device 53 as in the second embodiment.

-Other Embodiments- In the above embodiment,
The case where the present invention is applied to the gas engine 1 in which methane gas as a hydrocarbon-based fuel is reformed by the fuel reformer 51 to obtain a fuel having a large calorific value has been described. The present invention is not limited to this, and as the hydrocarbon fuel, it is also possible to apply fuels such as natural gas, petroleum liquid fuel, digestive gas, biogas, alcohol fuel and the like.

The present invention is applicable to gas engines used for various purposes, not limited to those for power generation.

Further, in order to further promote the endothermic reaction in the fuel reformer 51, reformed fuel (fuel after reforming, other than hydrogen) or carbonization is carried out inside the fuel reformer 51. It is also possible to adopt a configuration in which a part of the hydrogen-based fuel (fuel before reforming) is burned to raise the internal temperature of the fuel reformer 51. If this configuration is adopted, an extremely high conversion rate can be realized.

Further, in the above-mentioned embodiments and modified examples, the case where the steam and the hydrocarbon-based fuel are endothermicly reacted to reform the fuel has been described. However, the present invention is endothermic between carbon dioxide and the hydrocarbon-based fuel. It is also possible to apply it to what reacts and reforms fuel.

[0069]

As described above, according to the present invention, the hydrocarbon fuel is reformed by the fuel reformer and then the reformed fuel is supplied to the combustion chamber. Since a high-order desulfurization device capable of desulfurizing the sulfur content contained in the fuel to a ppb level is provided, poisoning of the catalyst in the fuel reformer is almost eliminated, and the life of this catalyst can be extended. .

When a hydrodesulfurization device for removing the sulfur content contained in the hydrocarbon fuel by hydrodesulfurization is provided on the upstream side of the high-order desulfurization device, it is introduced into the high-order desulfurization device. The amount of sulfur can be extremely reduced, and the efficiency of sulfur removal operation in the high-order desulfurization device can be improved and the life of the high-order desulfurization device can be extended.

Furthermore, when only the steam is supplied to the fuel reformer so that the performance of the poisoned catalyst in the fuel reformer can be restored, the catalyst can be regenerated, and this also enables the regeneration. The life of the catalyst can be extended.

Further, if heat is exchanged between the reformed fuel derived from the fuel reformer and the raw material introduced into the fuel reformer, the heat energy in the reformed fuel is reduced. It is possible to recover, and it is possible to increase the exhaust heat recovery amount.

In addition, heat is exchanged between the water contained in the post-reformation fuel discharged from the fuel reformer and the raw material introduced into the fuel reformer to be contained in the post-reformation fuel. When water is condensed and used as a part of the raw material for fuel reforming, the water contained in the fuel after reforming can be effectively used without being discarded, and the water supply The running cost of equipment can be reduced.

Further, by providing pure water generating means for removing impurities contained in water supplied to the steam generating means, impurities such as halogen and arsenic are contained in the steam supplied to the fuel reformer. It is possible to prevent this from happening, and thereby to prevent poisoning of the catalyst of the fuel reformer.
As a result, the life of the fuel reformer and the steam generator can be extended, and the cost can be reduced by eliminating the need for the pure water tank.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a power generation system that generates power by a gas engine according to a first embodiment.

FIG. 2 is a view corresponding to FIG. 1 in a second embodiment.

FIG. 3 is a view corresponding to FIG. 1 in a third embodiment.

FIG. 4 is a view corresponding to FIG. 1 in a conventional example.

[Explanation of symbols]

1 gas engine 51 Fuel reformer 52 Exhaust heat boiler (steam generation means) 53 High-order desulfurization equipment 56 Hydrodesulfurization equipment 57 heat exchanger 57a Water return pipe (water return route) 58 Pure Water Device (Pure Water Generation Means)

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Claims (10)

[Claims] 1. In a gas engine for reforming a hydrocarbon-based fuel by a fuel reformer and supplying the reformed fuel to a combustion chamber, the sulfur content in the hydrocarbon-based fuel is adjusted to ppb (parts per part). bil
A gas engine characterized by being equipped with a high-order desulfurization device capable of desulfurizing to the lion level. 2. The gas engine according to claim 1, wherein a hydrodesulfurization device for removing the sulfur content contained in the hydrocarbon fuel by hydrodesulfurization is provided upstream of the higher-order desulfurization device. Gas engine characterized by. 3. A gas engine for reforming a hydrocarbon-based fuel with a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein the fuel reformer includes a hydrocarbon-based fuel and steam. The hydrocarbon-based fuel is reformed by causing an endothermic reaction, and a steam generating means for generating the steam is provided, and an operating state in which the hydrocarbon-based fuel and steam are supplied to the fuel reformer. And a catalyst performance recovery processing state in which only steam is supplied to the fuel reformer. 4. The gas engine according to claim 3, wherein the ratio of steam to hydrocarbon fuel supplied in an operating state in which the hydrocarbon fuel and steam are supplied to the fuel reformer is 2.5 or more. A gas engine characterized by being set to 3.0 or less. 5. A gas engine for reforming a hydrocarbon-based fuel by a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein the fuel reformer includes a hydrocarbon-based fuel and steam. The hydrocarbon-based fuel is reformed by the endothermic reaction, and heat exchange is performed between the reformed fuel derived from the fuel reformer and the raw material introduced into the fuel reformer. A gas engine, which is equipped with a heat exchanger that preheats the raw material by going. 6. A gas engine for reforming a hydrocarbon-based fuel by a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein the fuel reformer includes a hydrocarbon-based fuel and steam. It is designed to reform hydrocarbon-based fuel by causing an endothermic reaction, and between the water contained in the reformed fuel derived from the fuel reformer and the raw material introduced into the fuel reformer. A heat exchanger for condensing the water contained in the fuel after reforming by heat exchange with the water, and a water return path for returning the water condensed in the heat exchanger as a part of the raw material for fuel reforming. A gas engine characterized by being 7. A gas engine for reforming a hydrocarbon-based fuel by a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein the fuel reformer includes a hydrocarbon-based fuel and steam. A hydrocarbon-based fuel is reformed by causing an endothermic reaction, and a steam generating means for generating the steam and a pure water generating means for removing impurities contained in water supplied to the steam generating means. A gas engine characterized by being equipped with. 8. The gas engine according to claim 7, wherein the pure water generating means is a halogen removing device for removing halogen contained in water. 9. The gas engine according to claim 7, wherein the pure water producing means is an arsenic removing device for removing arsenic contained in water. 10. A gas engine, which is configured by combining a plurality of configurations according to any one of claims 1 to 9.