Gas engine cogeneration device and its operation method

Abstract

To provide a gas engine cogeneration device including a storage housing of a reformer capable of increasing a temperature of a catalyst by utilizing heat of an exhaust gas of a gas engine.SOLUTION: A gas engine cogeneration device is a device including a reformer taking a mixture gas including a gas fuel and superheated steam and producing a reaction product as a reformed fuel via a catalyst, further includes a storage housing 300 for storing the reformer 130, a gas engine 110, a generator 111, and an exhaust gas boiler 120. The storage housing 300 is disposed on an intermediate position between a superheater 121 and an evaporator 122 inside of the exhaust gas boiler 120. An operation method for the gas engine cogeneration device includes exhausting an exhaust gas successively from the gas engine 110 to the superheater 121, from the superheater 121 to the storage housing 300, and from the storage housing 300 to the evaporator 122 to heat the reformer 130 by the exhaust gas.SELECTED DRAWING: Figure 1B

Description

Technical Field

[0001] The present invention relates to a gas engine cogeneration device and an operation method thereof.

Background Art

[0002] Conventionally, power generation systems equipped with stationary gas engines have been introduced into large-scale facilities and buildings with high power demand, such as factories, public facilities, and commercial facilities. Gas engines are known to have a high combustion temperature and high power generation efficiency among internal combustion engines. In recent years, the introduction as a cogeneration system that utilizes waste heat from fuel combustion together with the generated power has also been expanding.

[0003] Typical city gas as a fuel for gas engines is known as a clean fuel with relatively low generation amounts of CO 2 and NO x . Currently, the power generation efficiency of gas engines using city gas as fuel has been improved to about 40 - 50%, and the energy conversion efficiency of the entire system has also been significantly improved. On the other hand, in recent years, the popularization of hydrogen fuel has also been progressing.

[0004] Hydrogen fuel is a clean energy that does not emit harmful substances such as CO 2 , and raw materials such as hydrocarbons that can be chemically converted are also abundantly present. Therefore, in various fields, the replacement of existing energy with hydrogen fuel and the construction of infrastructure for using hydrogen fuel are underway. Conventionally, as a production method of hydrogen fuel, steam reforming has been used including large-scale production.

[0005] Steam reforming is a method of catalytically oxidizing hydrocarbons such as methane with superheated steam in the presence of a catalyst. When methane is used as a raw material for steam reforming, the reforming reaction is represented by the following reaction formula (I). CH 4 + H 2 O → CO + 3H 2 ···(I)

[0006] In addition, the carbon monoxide generated by Reaction Formula (I) is converted into carbon dioxide by a conversion reaction (shift reaction) accompanying the main reaction. The conversion reaction is represented by the following Reaction Formula (II). CO + H 2 O → CO 2 + H 2 ···(II)

[0007] Currently, the use of city gas mainly composed of methane as a raw material for steam reforming is also being considered. The reforming reaction represented by Reaction Formula (I) is an endothermic reaction, and the conversion reaction represented by Reaction Formula (II) is an exothermic reaction. However, overall, the reaction proceeds endothermically, so heating is required for steam reforming. General steam reforming is carried out at 600 - 700°C, up to about 900°C.

[0008] For example, Patent Document 1 describes a gas engine system including a reforming unit that takes in a mixed gas containing a gas fuel and superheated steam and generates a reaction product that becomes a reformed fuel, and a fuel supply device in which the reforming ability to generate the reformed fuel is adjusted according to the combustion characteristics of the internal combustion engine.

[0009] In addition, Patent Document 2 describes a methanol reforming type gas engine cogeneration device that uses methanol as a fuel, unlike Patent Document 1. In this device, the methanol reforming device is installed downstream of the gas engine device and upstream of the exhaust heat recovery boiler device, and the methanol reforming device is heated by the exhaust gas from the gas engine device.

Prior Art Documents

Patent Documents

[0010]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0011] In recent years, new types of gas engines introduced everywhere have improved combustion performance and energy conversion efficiency more than before due to improvements in engine structure, advancements in combustion technology, etc. Therefore, according to the new type of gas engine, it is possible to operate with high combustion efficiency compared to the old type of gas engine. Depending on the rated output of the gas engine, it is also possible to achieve a power generation efficiency close to 50% using city gas as fuel.

[0012] However, even at present, there are cases where old type gas engines are still in use. Since the old type of gas engine is inferior in combustion performance and energy conversion efficiency compared to the new type of gas engine, there is a current situation where it has to be operated with low combustion efficiency. In operation with low combustion efficiency, a large amount of fuel is required for the work amount, power amount, etc. to be extracted, resulting in high fuel costs and a decrease in the overall energy efficiency of the process.

[0013] On the other hand, the use of hydrogen gas as a fuel for gas engines is also being promoted. Hydrogen gas has the characteristic of a high combustion speed compared to hydrocarbons such as methane. Therefore, when using a fuel containing hydrogen gas as the fuel for an internal combustion engine, it becomes possible to operate with high combustion efficiency, and even when using an old type of gas engine, energy saving and energy conversion efficiency can be improved.

[0014] However, in the reforming unit described in Patent Document 1, when raising the temperature of the catalyst from room temperature to the reaction temperature at the start of the reformer, the heat of superheated steam is utilized. Depending on the temperature of the superheated steam, it has been confirmed that the material constituting the catalyst undergoes a hydroxylation reaction. When the hydroxylation reaction occurs, problems such as an increase in the pressure loss of the reformer due to the alteration and deformation of the material constituting the catalyst, and a decrease in the flow rate of the gas introduced into the reformer occur. Therefore, it is necessary to raise the temperature of the catalyst to a temperature above the margin where no hydroxylation reaction occurs from room temperature using something other than superheated steam.

[0015] On the other hand, in the reformer described in Patent Document 2, the heat of the exhaust gas from the gas engine device is used to raise the temperature of the catalyst layer and the raw material gas. The reformer is disposed on the exhaust gas path of the exhaust gas, downstream of the gas engine device and upstream of the exhaust heat recovery boiler device. In this arrangement, since high-temperature exhaust gas is supplied to the reformer, the catalyst inside the reformer is also heated to a high temperature. Depending on the type of catalyst, deterioration is likely to occur at high temperatures, so a temperature control mechanism such as a control damper is required to control the temperature within an appropriate range.

[0016] Patent Document 2 states that when operating with a Cu-Zn-Cr-based catalyst at LHSV (Liquid Hourly Space Velocity) = 1.0 h -1 it is desirable that the reaction temperature of the steam reforming reaction be 250°C to 300°C, and in the case of the methanol decomposition reaction, it is desirable that the temperature be 300 to 350°C. It is also described that if the reaction temperature is too high (for example, 350°C or higher), catalyst deterioration is likely to occur, which is not preferable from the perspective of the strength of the constituent materials of the reformer.

[0017] In addition, Patent Document 2 is provided with a bypass duct. Since the exhaust gas at the start of the gas engine device is at a low temperature, the exhaust gas discharged from the gas engine device is sent to the bypass duct, bypassing the reformer and sent to the exhaust heat recovery boiler device. Also, in Patent Document 2, methanol vapor is used as the starting reactant for the reforming reaction. Patent Document 2 describes that at the start of the gas engine device, the line of the engine jacket cooling water is cooled and methanol vapor is not generated in the methanol vapor generator, so it is heated by a starting electric heater.

[0018] In the field of gas engine cogeneration devices, there is a need for a system that can raise the temperature of the catalyst inside the reformer to an appropriate temperature at the start of the reformer, even without providing such a temperature control mechanism, bypass duct, starting electric heater, etc. It is necessary to quickly raise the temperature of the catalyst to a temperature with a margin that does not cause a hydroxide reaction from room temperature, using something other than superheated steam before the introduction of superheated steam, so that the materials constituting the catalyst do not cause a hydroxide reaction.

[0019] Therefore, an object of the present invention is to provide a gas engine cogeneration device including a storage housing for a reformer that can raise the temperature of a catalyst by utilizing the heat of the exhaust gas of a gas engine.

Means for Solving the Problems

[0020] To solve the above problems, a gas engine cogeneration device according to the present invention is a gas engine cogeneration device including a reformer that takes in a mixed gas containing gas fuel and superheated steam and generates a reaction product that becomes reformed fuel through a catalyst, wherein the gas engine cogeneration device includes a storage housing that houses the reformer, a gas engine, a generator driven by the gas engine, and an exhaust gas boiler heated by the exhaust gas from the gas engine, and the storage housing is disposed at an intermediate position between a superheater and an evaporator inside the exhaust gas boiler , The superheated steam generated by the superheater is supplied to the reformer characterized by this.

[0021] Also, an operation method of a gas engine cogeneration device according to the present invention is an operation method of a gas engine cogeneration device including a reformer that takes in a mixed gas containing gas fuel and superheated steam and generates a reaction product that becomes reformed fuel through a catalyst, wherein the gas engine cogeneration device includes a storage housing that houses the reformer, a gas engine, a generator driven by the gas engine, and an exhaust gas boiler heated by the exhaust gas from the gas engine, and the storage housing is disposed at an intermediate position between a superheater and an evaporator inside the exhaust gas boiler , The superheated steam generated by the superheater is supplied to the reformer That is, the operation method of the gas engine cogeneration device exhausts the exhaust gas from the gas engine in the order of from the gas engine to the superheater, from the superheater to the storage housing, and from the storage housing to the evaporator, heats the reformer stored in the storage housing with the exhaust gas, supplies the mixed gas to the reformer to generate the reaction product, and supplies the reaction product to the gas engine to operate the gas engine.

Effect of the Invention

[0022] According to the present invention, it is possible to provide a gas engine cogeneration device including a storage housing of a reformer capable of raising the temperature of a catalyst by utilizing the heat of the exhaust gas of the gas engine.

Brief Description of the Drawings

[0023]

Figure 1A

Figure 1B

Figure 2A

Figure 2B

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Figure 4B

Figure 4C

Figure 4D

Figure 5A

Figure 5B

Figure 5C

Figure 5D

Figure 6A

Figure 6B

Figure 7

Figure 8A

Figure 8B

Figure 8C

Figure 8D

Figure 9

Mode for Carrying Out the Invention

[0024] Hereinafter, a gas engine cogeneration device and an operation method thereof according to an embodiment of the present invention will be described with reference to the drawings. In the following respective drawings, the same reference numerals are given to common configurations and redundant descriptions are omitted.

[0025] FIG. 1A is a diagram showing a schematic system of a conventional gas engine cogeneration device. FIG. 1A shows a schematic system used in the gas engine system described in Patent Document 1. In FIG. 1A, solid arrows indicate the flow of city gas, broken arrows indicate the flow of reformed gas, two-dot chain arrows indicate the flow of superheated steam, and white arrows indicate the flow of exhaust gas.

[0026] As shown in Fig. 1A, a conventional gas engine cogeneration device includes a gas engine 110, a generator 111, an exhaust gas boiler 120, a reformer 130, and a heat exchanger 140. The exhaust gas boiler 120, the reformer 130, and the heat exchanger 140 constitute a fuel reforming device. The exhaust gas boiler 120 and the reformer 130 are provided separately.

[0027] The gas engine cogeneration device is a device that extracts combustion energy from the combustion of gas fuel as mechanical energy by the gas engine 110 and recovers and utilizes the exhaust heat accompanying the combustion. According to the gas engine cogeneration device, since the exhaust heat of the gas engine 110 is recovered and utilized, high energy efficiency can be obtained for the entire system. The energy efficiency per unit amount of gas fuel used is improved, promoting energy saving of the system, reduction of operating costs, and reduction of carbon emissions.

[0028] The gas engine 110 is an internal combustion engine that burns gaseous gas fuel, burns the gas fuel supplied to the combustion chamber, and converts the force due to the expansion of the fluid in the combustion chamber into mechanical energy. The power generated by the gas engine 110 is supplied to the turbine of the generator 111 and used for power generation. According to the gas engine 110, high combustion efficiency, stable torque, and fuel consumption characteristics can be obtained compared with other internal combustion engines such as gas turbines.

[0029] As the fuel of the gas engine 110, hydrocarbon-based fuels mainly composed of methane, reformed gas generated by steam reforming of methane, or a mixed gas of these is used. Examples of hydrocarbon-based fuels include city gas such as 13A and 12A. 13A, which is a typical city gas, is a mixed gas containing about 90% methane and less than about 10% ethane, propane, and butane.

[0030] City gas is supplied to the gas engine 110 from outside the system through a city gas supply line connected to a gas pipeline network or the like. The city gas is also supplied to the reformer 130 via a branch line branching off from the city gas supply line and via a heat exchanger 140. The type of fuel and supply flow rate of the gas engine 110 are switched according to the operating conditions of the system in order to stabilize combustion at the start of the gas engine 110 and reduce carbon emissions.

[0031] The reformed gas is supplied to the gas engine 110 from the reformer 130 via a reformed gas supply line via a heat exchanger 140. The heat exchanger 140 exchanges heat between the city gas for the reforming reaction supplied to the reformer 130 and the reformed gas supplied from the reformer 130 to the gas engine 110. The reformed gas is cooled by the heat exchange to a temperature and relative humidity that are acceptable for the gas engine 110. The city gas for the reforming reaction is preheated by heat exchange before the reforming reaction.

[0032] The mixed gas is generated by mixing city gas supplied to the gas engine 110 from outside the system with reformed gas supplied to the gas engine 110 from the reformer 130 via the heat exchanger 140. The mixed gas is generated at a junction (not shown) where the city gas supply line and the reformed gas supply line join, and then supplied to the gas engine 110.

[0033] The exhaust gas boiler 120 is a boiler that heats water by utilizing the heat of exhaust gas. Exhaust gas discharged from the combustion chamber of the gas engine 110 is supplied to the exhaust gas boiler 120. The exhaust gas boiler 120 generates high-temperature superheated steam that is superheated to a temperature equal to or higher than the reaction temperature of the reforming reaction by utilizing the heat of the exhaust gas. After the exhaust gas is thermally utilized in the exhaust gas boiler 120, it is released into the environment, etc.

[0034] The exhaust gas boiler 120 includes a superheater 121 and an evaporator 122. The superheater 121 heats saturated steam to generate superheated steam. In the superheater 121, heat exchange occurs between the exhaust gas discharged from the gas engine 110 and the saturated steam supplied from the evaporator 122. The evaporator 122 heats water to generate steam. In the evaporator 122, heat exchange occurs between the exhaust gas that has been discharged from the gas engine 110 and passed through the superheater 121 and the water.

[0035] In the exhaust gas boiler 120, water supplied from an external source or condensed water after the reforming reaction can be used as water for heat exchange. The condensed water is recovered by condensing the reaction product of the reforming reaction generated in the reformer 130. The superheated steam generated by the exhaust gas boiler 120 is supplied to the reformer 130. Before being supplied to the reformer 130, the superheated steam may be heat exchanged with city gas for the reforming reaction.

[0036] The reformer 130 is a reactor that takes in a mixed gas containing gas fuel and superheated steam, and generates a reaction product that becomes a reformed fuel through a catalyst. A mixed gas of city gas and superheated steam is introduced into the reformer 130. The reformer 130 hydrogen-reforms (steam reforms) hydrocarbons such as methane with steam, generating a reformed gas mainly composed of hydrogen. The reformed gas is supplied from the reformer 130 to the gas engine 110.

[0037] The reformed gas is generated in the reformer 130 from city gas, the main component of which is methane, and superheated steam according to reaction formula (I) or reaction formula (II). The reformed gas is generated by mixing hydrogen (H 2 ), unreacted methane (CH 4 ) and carbon dioxide (CO 2 The reforming reaction, including the conversion reaction, proceeds endothermically overall. Therefore, preheated city gas for the reforming reaction and high-temperature superheated steam generated by the exhaust gas boiler 120 are introduced into the reformer 130.

[0038] Hydrogen, which is the main component of the reformed gas, has the properties of a high combustion rate and high combustion stability compared to hydrocarbons such as methane. Therefore, when using the reformed gas as fuel, not only is the carbon emission reduced, but the combustion efficiency of the gas engine 110 is also increased. Even when the combustion characteristics of the gas engine 110 are inferior in terms of performance, the total combustion energy (calorific value) generated by the gas engine 110 can be increased.

[0039] As shown in FIG. 1A, in a conventional gas engine cogeneration device, a mixed gas of city gas and superheated steam for reforming reaction is supplied to the reformer 130, but the exhaust gas discharged from the gas engine 110 is not supplied. Conventionally, the catalyst inside the reformer 130 has been heated by the superheated steam in the mixed gas from room temperature to the reaction temperature. The city gas and superheated steam are heated up after starting the gas engine 110 or the like. However, it is at a low temperature when the gas engine 110 is started.

[0040] With such a conventional configuration, the inventors have confirmed that problems occur in the operation of the reformer. In the process of repeating the operation test, an event was confirmed in which the pressure loss of the reformer increased and the flow rate of the gas introduced into the reformer decreased significantly. When the cause was investigated, significant alteration and deformation were observed in the catalyst inside the reformer. As a result of analyzing the catalyst, it was found that aluminum forming the catalyst carrier and support material had undergone a hydroxylation reaction. It was found that the hydroxylation reaction caused deformation such as alteration and expansion, and the gas flow path inside the reformer was blocked.

[0041] Subsequent verification confirmed that the hydroxylation reaction of aluminum proceeds when the aluminum material is in contact with water at 200 ° C or lower. In order not to cause the hydroxylation reaction, it was concluded that it is appropriate to perform the catalyst heating with a target temperature of 250 ° C, which is a temperature with a margin not to cause the hydroxylation reaction, in the absence of water during the temperature increase process of the catalyst inside the reformer from room temperature.

[0042] Based on this knowledge, we came up with the idea of ​​placing a reformer containing a catalyst for the reforming reaction halfway between the superheater and the evaporator in the flow path of exhaust gas from the gas engine. By using the heat of the exhaust gas sent from the superheater to the evaporator to heat the outer surface of the reformer, we were able to rapidly raise the temperature of the catalyst from room temperature to 250°C, a temperature that allows a margin of error that will not cause a hydroxylation reaction, in the absence of water.

[0043] Fig. 1B is a diagram showing a schematic system of the gas engine cogeneration system according to this embodiment. In Fig. 1B, the solid arrows indicate the flow of city gas, the dashed arrows indicate the flow of reformed gas, the two-dot chain arrows indicate the flow of superheated steam, and the hollow arrows indicate the flow of exhaust gas. 1B, the gas engine cogeneration system according to this embodiment includes a gas engine 110, an exhaust gas boiler 120, and a heat exchanger 140. The exhaust gas boiler 120 includes a superheater 121, a housing 300 in which a reformer 130 is housed, and an evaporator 122.

[0044] The gas engine cogeneration system according to this embodiment differs from conventional gas engine cogeneration systems in that a reformer 130 that performs steam reforming is disposed inside the exhaust gas boiler 120. The reformer 130 is housed in a duct-shaped housing 300 that forms a flow path of the exhaust gas, and the housing 300 is disposed inside the exhaust gas boiler 120, at an intermediate position between the superheater 121 and the evaporator 122 in the flow path of the exhaust gas from the gas engine 110.

[0045] According to this arrangement, the catalyst inside the reformer 130 is heated by the exhaust gas discharged from the gas engine 110. The exhaust gas flows in the following order: from the gas engine 110 to the superheater 121, from the superheater 121 to the storage housing 300, and from the storage housing 300 to the evaporator 122. As the exhaust gas flows through the inside of the storage housing 300, it comes into contact with the outer circumferential surface of the reformer 130 and heats the catalyst inside.

[0046] The temperature of the exhaust gas discharged from the gas engine 110 is about 400 to 600 °C, and is 505 °C as an example. The reformer 130 housed in the storage housing 300 is rapidly heated to the reaction temperature of the reforming reaction by the high-temperature exhaust gas. The reaction temperature of the reforming reaction is 300 °C or higher, preferably 400 °C or higher, and is 420 °C as an example. The temperature of the exhaust gas passing through the superheater 121 becomes about 420 °C.

[0047] After the catalyst inside the reformer 130 housed in the storage housing 300 is heated to a predetermined temperature, city gas mainly composed of methane and superheated steam are supplied. The city gas for the reforming reaction is supplied to the reformer 130 via the heat exchanger 140 through a branch line branched from the city gas supply line. The superheated steam is supplied to the reformer 130 from the superheater 121 of the exhaust gas boiler 120 through the superheated steam supply line. The temperature of the superheated steam is 300 °C or higher, preferably 400 °C or higher, and is 420 °C as an example.

[0048] Thus, in the gas engine cogeneration device according to the present embodiment, the storage housing 300 is installed on the exhaust gas flow path inside the exhaust gas boiler 120, and the reformer 130 is housed in the storage housing 300. Therefore, during the start-up of the reformer 130 or during the operation of the reformer 130, the reformer 130 can be heated by the heat of the exhaust gas. At the start of the reformer 130, the catalyst can be heated up to 250 °C, which is a temperature with a margin that does not cause a hydroxylation reaction from room temperature, in the absence of water before superheated steam is introduced into the reformer 130. Also, it can be carried out at a rapid heating rate by the high-temperature exhaust gas.

[0049] When the reformer 130 is heated by the heat of the exhaust gas, the catalyst can be heated up to 250 °C, which is a temperature with a margin that does not cause a hydroxylation reaction from room temperature, in the absence of water and at a rapid heating rate. Therefore, when aluminum is used as the catalyst material, deformations such as catalyst deterioration and expansion are reduced. Therefore, it becomes possible to use aluminum as the catalyst material. Also, since catalyst deterioration and deformation are reduced and blockage of the gas flow path is prevented, the gas flow rate can be maintained at a stable high flow rate.

[0050] In addition, when the reformer 130 is heated by the heat of the exhaust gas, the time required to raise the temperature to the optimum temperature of the reforming reaction can be shortened as compared with the case of heating with conventional superheated steam. This is because the exhaust gas is at a high temperature immediately after the gas engine 110 is started. During the operation of the reformer 130, the temperature inside the reformer 130 can be maintained at an appropriate reaction temperature by the exhaust gas supplied from the gas engine 110 and the superheated steam introduced into the reformer 130.

[0051] Further, if the reformer 130 is configured to be heated by the heat of the exhaust gas, there is no need to provide a new heat source for the purpose of raising the temperature inside the reformer 130 to the reaction temperature of the reforming reaction or for the purpose of preventing the aluminum hydroxide reaction. The installation cost, operation cost when providing a new heat source, and the piping system for the new heat source can be omitted. Therefore, a gas engine cogeneration device with low cost and high energy efficiency can be realized.

[0052] FIG. 2A is a diagram showing the appearance of the catalyst unit housed in the reformer. FIG. 2B is a diagram showing the layer structure of the catalyst unit housed in the reformer. In FIGS. 2A and 2B, reference numeral 200 denotes a catalyst unit, reference numeral 201 denotes a support member, and reference numeral 202 denotes a catalyst layer. Reference symbol C W denotes the outer diameter of the catalyst unit, and reference symbol C H denotes the thickness of the catalyst unit.

[0053] As shown in FIG. 2A, the catalyst unit 200 housed in the reformer 130 is formed into a columnar wound body by winding the catalyst sheet in a spiral shape. As shown in FIG. 2B, the catalyst sheet is formed by a sheet-like support member 201 and a catalyst layer 202. The catalyst layer 202 is formed on the support member 201. The catalyst layer 202 can be formed, for example, on both the front and back surfaces of the support member 201.

[0054] The support member 201 mechanically holds the structure of the catalyst unit 200. The wound support member 201 can contribute to heat conduction from the outer side to the inner side in the radial direction of the catalyst unit 200. The catalyst layer 202 supports a catalyst active component (not shown) that catalyzes the reforming reaction. The catalyst unit 200 is provided in a porous manner by sintering of particles, fiber forming, or the like. In the wound body of the catalyst unit 200, a gas flow path is formed in a porous manner in a direction parallel to the winding axis.

[0055] The support member 201 can be formed of, for example, aluminum, an aluminum alloy, or the like. The catalyst layer 202 is formed of a catalyst component and a catalyst carrier that supports the catalyst component. The catalyst carrier can be formed of, for example, aluminum oxide (Al 2 O 3 ). Although the present invention is based on measures to prevent the occurrence of the aluminum hydroxide reaction, materials other than aluminum, aluminum alloy, and aluminum oxide may be used for the support member 201 and the catalyst layer 202.

[0056] The catalyst unit 200 is housed in a cylindrical reformer 130 with the winding axis parallel to the central axis of the reformer 130. The outer diameter C w of the catalyst unit can be designed according to the inner diameter of the reformer 130 and the like. The thickness C H of the catalyst unit can be designed according to the storage range of the catalyst unit 200 for the reformer 130, the number of catalyst units 200 that can be stored in the reformer 130, and the like.

[0057] FIG. 3 is a diagram showing the structure of the reformer housed in the storage housing. In FIG. 3, reference numeral 130 denotes the reformer, reference numeral 131 denotes the container portion, reference numeral 132 denotes the lid portion, reference numeral 133 denotes the connecting pipe, reference numeral 134 denotes the connecting flange, and reference numeral 200 denotes the catalyst unit. Reference symbol L denotes the storage range of the catalyst unit, and reference symbol N denotes the number of catalyst units stored. Reference symbol Da denotes the outer diameter of the container portion, and reference symbol Db denotes the outer diameter of the connecting flange.

[0058] As shown in FIG. 3, the reformer 130 includes a cylindrical container portion 131, a lid portion 132 that closes the opening of the container portion 131, a tubular connection pipe 133 connected to the lid portion 132, and a connection flange 134 provided at the end of the connection pipe 133. The lid portion 132, the connection pipe 133, and the connection flange 134 are symmetrically provided on both sides of the container portion 131.

[0059] The container portion 131 is provided with a cylindrical hollow structure capable of accommodating the catalyst unit 200. One or more catalyst units 200 are accommodated in the container portion 131. The plurality of catalyst units 200 are stacked and accommodated concentrically with respect to the central axis of the container portion 131. The catalyst unit 200 is accommodated such that the side surface of the wound body is close to the inner peripheral surface of the container portion 131. Flange portions 131a for connecting to the lid portion 132 are formed at both ends of the container portion 131.

[0060] The lid portion 132 is provided as a hemispherical cover. A through hole is formed at the top of the lid portion 132, and the connection pipe 133 is joined so as to be connected to the through hole. A flange portion 132a for connecting to the container portion 131 is formed on the base side of the lid portion 132. After the catalyst unit 200 is accommodated in the container portion 131, the lid portion 132 is closed by flange connection.

[0061] The connection pipe 133 is provided as a tubular shape with a smaller diameter than the container portion 131. The connection pipe 133 communicates the inside of the container portion 131 with the outside of the reformer 130. A connection flange 134 is formed at the end of the connection pipe 133. The connection flange 134 is flange-connected to other pipes. Examples of other pipes include a pipe for supplying a mixed gas for the reforming reaction and a pipe for supplying the reformed gas to the gas engine 110.

[0062] The container part 131, the lid part 132, and the connecting pipe 133 are formed of a heat-resistant material that can withstand the reaction temperature of the reforming reaction. As the materials for the container part 131, the lid part 132, the connecting pipe 133, and the connecting flange 134, appropriate materials such as carbon steel, low-alloy steel, and stainless steel can be used according to the temperature of the reforming reaction, cost, etc.

[0063] The accommodatable range L of the catalyst unit means the range within the internal space of the reformer 130 where the catalyst unit 200 can be accommodated. The accommodatable range L of the catalyst unit is such that when the reformer 130 is accommodated in the housing 300, the outer peripheral surface of the reformer 130 is directly heated by the exhaust gas discharged from the gas engine 110.

[0064] The length of the accommodatable range L of the catalyst unit is preferably set smaller than the width of the exhaust gas flow path inside the housing 300. With such a design, the catalyst accommodated in the reformer 130 can be heated with high uniformity by the exhaust gas discharged from the gas engine 110. The accommodatable range L of the catalyst unit can be designed based on the flow rate of the mixed gas introduced into the reformer 130 and the target reforming rate of the mixed gas under such conditions.

[0065] The number N of catalyst units to be accommodated means the number of catalyst units 200 accommodated per one reformer 130. The number N of catalyst units to be accommodated is determined by the relationship between the accommodatable range L of the catalyst unit and the thickness C H of the catalyst unit. The number N of catalyst units to be accommodated is preferably maximized within the accommodatable range L of the catalyst unit according to the thickness C H of the catalyst unit.

[0066] The outer diameter Db of the connecting flange 134 is preferably provided to be equal to or less than the outer diameter Da of the container part 131 (Db ≧ Da). With such dimensions, when inserting or removing the reformer 130 with respect to the cylindrical accommodating part 310 provided in the housing 300, physical interference of the connecting flange 134 can be prevented.

[0067] FIG. 4A is a front view of a storage housing in which a reformer is housed. FIG. 4B is a plan view of the storage housing in which the reformer is housed. FIG. 4C is a side view of the storage housing in which the reformer is housed, viewed from the exhaust gas inlet side. FIG. 4D is a side view of the storage housing in which the reformer is housed, viewed from the exhaust gas outlet side. In FIGS. 4A to 4D, reference numeral 300 denotes a storage housing, reference numeral 301 denotes a lower surface portion, reference numeral 302 denotes an upper surface portion, reference numeral 303 denotes an inlet front portion, reference numeral 304 denotes an outlet front portion, reference numeral 305 denotes an inlet rear portion, reference numeral 306 denotes an outlet rear portion, reference numeral 307 denotes an inlet connection portion, reference numeral 308 denotes an outlet connection portion, reference numeral 309 denotes a lifting tool, and reference numeral 310 denotes a storage portion. In FIG. 4B, reference numeral D denotes the depth dimension of the storage housing, and the white arrow indicates the direction of insertion or extraction of the reformer.

[0068] The storage housing 300 is provided in a duct shape with a substantially rectangular cross section. The storage housing 300 has open left and right side surfaces, and the gas can flow through the interior in the left-right direction. As shown in FIG. 4A, the exhaust gas discharged from the gas engine 110 flows in the left-right direction inside the storage housing 300. The storage housing 300 has a lower surface portion 301, an upper surface portion 302, front portions 303 and 304, and rear portions 305 and 306.

[0069] An inlet connection portion 307 is formed on the gas inlet side of the storage housing 300. The inlet connection portion 307 is formed by an opening opened on the side surface of the storage housing 300 and a flange around the opening. An outlet connection portion 308 is formed on the gas outlet side of the storage housing 300. The outlet connection portion 308 is formed by an opening opened on the side surface of the storage housing 300 and a flange around the opening.

[0070] The inlet connection portion 307 is connected to the superheater 121 of the exhaust gas boiler 120. The inlet connection portion 307 forms an opening for taking the exhaust gas discharged from the superheater 121 into the interior of the storage housing 300. The inlet connection portion 307 is provided in accordance with the duct diameter for discharging the exhaust gas of the superheater 121. The inlet connection portion 307 is connected to the outlet side of the exhaust gas duct of the superheater 121 by flange connection.

[0071] The outlet connection part 308 is connected to the evaporator 122 of the exhaust gas boiler 120. The outlet connection part 308 forms an opening for discharging exhaust gas from the inside of the storage housing 300. The outlet connection part 308 is provided in accordance with the diameter of a duct that sucks in the exhaust gas of the evaporator 122. The outlet connection part 308 is connected to the inlet side of the exhaust gas duct of the evaporator 122 by a flange connection.

[0072] A hoist 309 is attached to the upper part of the storage housing 300. The hoist 309 is used to hoist the storage housing 300 with a crane, a hoist, or the like when the storage housing 300 is transported or installed. The storage housing 300 may replace an existing duct that connects the exhaust gas duct of the superheater 121 and the exhaust gas duct of the evaporator 122.

[0073] The front parts 303, 304 and the rear parts 305, 306 are trapezoidal in a front view or a rear view of the storage housing 300. The upper part 302 is inclined downward from the gas inlet side to the gas outlet side. As shown in Figs. 4C and 4D, the opening of the outlet side connection part 308 is provided with a smaller diameter than the opening of the inlet side connection part 307. The storage housing 300 is provided with a shape that narrows the gas flow path from the superheater 121 to the evaporator 122 in a front view or a rear view of the storage housing 300.

[0074] Of the front sections 303, 304, the gas inlet side is formed by the inlet-side front section 303, and the gas outlet side is formed by the outlet-side front section 304. Of the rear sections 305, 306, the gas inlet side is formed by the inlet-side rear section 305, and the gas outlet side is formed by the outlet-side rear section 306. As shown in Figures 4A and 4B, the inlet-side front section 303 and the inlet-side rear section 305 are provided longer in the left-right direction than the outlet-side front section 304 and the outlet-side rear section 306.

[0075] As shown in FIG. 4B, in the plan view of the storage housing 300, the inlet front surface portion 303 and the inlet rear surface portion 305 are provided in parallel with each other. On the other hand, the outlet front surface portion 304 and the outlet rear surface portion 306 are provided to be inclined inward as going from the gas inlet side to the outlet side. The storage housing 300 is provided in a shape that narrows the gas flow path from the superheater 121 toward the evaporator 122 in the plan view of the storage housing 300.

[0076] The storage housing 300 includes a plurality of storage portions 310 for storing the reformer 130. The storage portion 310 is formed by a cylindrical sleeve tube. The storage portion 310 is provided so as to penetrate the inlet front surface portion 303 and the inlet rear surface portion 305. The storage portion 310 penetrates the storage housing 300 in the front-rear direction and is provided in a structure that crosses the exhaust gas flow path inside the storage housing 300.

[0077] A plurality of through holes are formed in the inlet front surface portion 303 and the inlet rear surface portion 305 in a concentric arrangement with each other on the front side and the rear side. The sleeve tube forming the storage portion 310 is inserted into these through holes. The sleeve tube inserted into the through holes is joined to the inlet front surface portion 303 and the inlet rear surface portion 305 by bolt fastening or the like.

[0078] In FIG. 4A, a total of 15 storage portions 310 are provided in a 5-row × 3-column arrangement in the vertical direction. The plurality of storage portions 310 are arranged so as to cross the exhaust gas flow path in parallel with each other. However, the storage portions 310 can be provided in an appropriate number and arrangement according to the target production amount of the reformed gas, the flow rate of the exhaust gas, the pressure loss of the exhaust gas flow path, and the like.

[0079] The lower surface portion 301, the upper surface portion 302, the front surface portions 303 and 304, the rear surface portions 305 and 306 of the storage housing 300, and the storage portion 310 are formed of a heat-resistant material that can withstand the temperature of the exhaust gas discharged from the gas engine 110. As the material of the storage housing 300, carbon steel, low alloy steel, stainless steel, etc. can be used according to the temperature of the exhaust gas, cost, etc.

[0080] The depth dimension D of the storage housing 300 is preferably set in accordance with the duct diameter for discharging the exhaust gas of the superheater 121 within a range that fits within the depth dimension of the superheater 121 of the exhaust gas boiler 120. The depth dimension D of the storage housing 300 is preferably designed such that, based on the flow rate of the mixed gas that is the starting reactant of the reforming reaction and the target reforming rate of the mixed gas, the maximum number of catalyst units 200 provided with a predetermined thickness are arranged, that is, the total thickness of the catalyst units 200 is maximized.

[0081] FIG. 5A is a side view of the storage portion provided in the storage housing. FIG. 5B is a front view of the storage portion provided in the storage housing. FIG. 5C is a cross-sectional view of the storage portion provided in the storage housing. FIG. 5D is a partially enlarged front view of the storage housing showing the arrangement of the storage portion. In FIGS. 5A to 5D, reference numeral 310 denotes a storage portion, reference numeral 311 denotes a container portion, reference numeral 312 denotes a flange, and reference numeral 313 denotes an opening. In FIG. 5D, reference numeral A denotes a region where an opening is formed, reference numeral ΔW denotes the horizontal interval of the storage portion, and reference numeral Δh denotes the vertical interval of the storage portion.

[0082] As shown in FIG. 5A, the storage portion 310 formed by a sleeve tube includes a cylindrically provided container portion 311, a flange 312 provided at the end of the container portion 311, and an opening 313 that opens on the outer peripheral surface of the container portion 311. The flange 312 is provided symmetrically on both sides of the container portion 311.

[0083] The container portion 311 is provided in a cylindrical shape and forms a hollow structure capable of housing the reformer 130. One reformer 130 is housed in the container portion 311 in a direction such that the central axis of the reformer 130 is parallel to the central axis of the container portion 311. The inner diameter of the container portion 311 is provided slightly smaller than the outer diameter of the reformer 130.

[0084] The flange 312 is used for fixing the reformer 130 to the storage portion 310. A fixing mechanism using a shaft seal member is joined to the flange 312 by bolt fastening.

[0085] The opening 313 is formed in a window shape in the peripheral wall of the container portion 311. The opening 313 penetrates the peripheral wall of the container portion 311 and communicates the exhaust gas flow path inside the storage housing 300 with the inside of the container portion 311. One or more appropriate numbers of the openings 313 can be provided in the peripheral wall of the container portion 311.

[0086] As shown in FIG. 5A, the opening 313 is formed in a section of the outer peripheral surface of the storage portion 310 that is located in the exhaust gas flow path inside the storage housing 300 in the longitudinal direction of the storage portion 310. The opening 313 is preferably formed over substantially the entire width of the section of the outer peripheral surface of the storage portion 310 that is located in the exhaust gas flow path, excluding the frame portion provided between the openings 313.

[0087] As shown in FIG. 5C, in a cross-sectional view of the storage portion 310, the opening 313 is provided symmetrically with respect to a line on each of the peripheral wall on the gas inlet side of the storage portion 310 and the peripheral wall on the gas outlet side of the storage portion 310. The opening 313 is preferably provided so as to open at an angle of about 60 degrees or more upward and downward from the horizontal plane passing through the center of the storage portion 310 in the outer peripheral surface of the storage portion 310 on each of the gas inlet side and the gas outlet side.

[0088] When the opening 313 is provided, the exhaust gas flowing into the inside of the storage housing 300 from the superheater 121 can flow through the inside of the storage portion 310 through the opening 313. When the inner diameter of the container portion 311 is provided slightly smaller than the outer diameter of the reformer 130, a slight gap is formed between the inner peripheral surface of the container portion 311 and the outer peripheral surface of the reformer 130 when the reformer 130 is stored in the storage portion 310. The exhaust gas flowing into the inside of the storage portion 310 can flow through this gap.

[0089] In the process of the exhaust gas flowing through the interior of the storage housing 300, the outer peripheral surface of the reformer 130 stored in the storage section 310 can be directly heated by contact with the exhaust gas. Since the high-temperature exhaust gas of about 400°C or higher contacts the outer peripheral surface of the reformer 130 through the opening 313, the catalyst inside the reformer 130 can be rapidly heated. Therefore, before the mixed gas of city gas and superheated steam for the reforming reaction is introduced into the reformer 130, the catalyst can be heated to the reaction temperature of the reforming reaction while preventing the aluminum hydroxide reaction that forms the catalyst carrier and the support material.

[0090] As shown in FIG. 5D, it is preferable that the plurality of storage sections 310 are arranged with intervals provided between the storage sections 310, and between the storage sections 310 and the lower surface portion 301 and the upper surface portion 302 that form the inner wall of the exhaust gas flow path at the front inlet side surface portion 303 and the rear inlet side surface portion 305. The horizontal interval ΔW between the storage sections 310 and the vertical interval Δh between the storage sections 310 can be designed according to the outer diameter of the storage section 310, the number of arrangements of the storage sections 310, and the like.

[0091] According to such a structure, since the exhaust gas flowing into the interior of the storage housing 300 can flow between the storage sections 310 and between the storage sections 310 and the inner wall of the exhaust gas flow path, the pressure loss of the exhaust gas can be reduced. Each reformer 130 stored in the storage section 310 can be heated with high uniformity by the heat of the exhaust gas to reduce temperature unevenness. Therefore, the reforming reaction for each reformer 130 can proceed uniformly, and the reforming rate of the mixed gas as a whole can be improved.

[0092] FIG. 6A is a front view of the storage housing showing the arrangement of the storage housing. FIG. 6B is a plan view of the storage housing showing the arrangement of the storage housing. In FIGS. 6A and 6B, reference numeral 121 indicates a portion of the duct that discharges the exhaust gas of the superheater, reference numeral 122 indicates a portion of the duct that inhales the exhaust gas of the evaporator, reference numeral 130 indicates the reformer, reference numeral 300 indicates the storage housing, and reference numeral 310 indicates the storage section. In FIGS. 6A and 6B, the white arrows indicate the flow of the exhaust gas.

[0093] As shown in FIGS. 6A and 6B, the storage housing 300 is disposed inside the exhaust gas boiler 120 at an intermediate position between the superheater 121 and the evaporator 122 in the exhaust gas flow path from the gas engine 110. The inlet connection portion 307 at one end of the storage housing 300 is connected to the outlet side of the duct that discharges the exhaust gas of the superheater 121. The outlet connection portion 308 at the other end of the storage housing 300 is connected to the inlet side of the duct that sucks the exhaust gas of the evaporator 122.

[0094] When the storage housing 300 is disposed at an intermediate position between the superheater 121 and the evaporator 122 inside the exhaust gas boiler 120, the reformer 130 can be installed inside the exhaust gas boiler 120. The exhaust gas boiler 120 that generates superheated steam by utilizing the heat of the exhaust gas and the reformer 130 that generates reformed gas by utilizing the superheated steam are integrated. Therefore, in the configuration where the catalyst for the reforming reaction is heated up by utilizing the heat of the exhaust gas, the system can be made compact.

[0095] The reformer 130 is accommodated so as to cross the exhaust gas flow path with respect to the accommodation portion 310 provided in a structure that crosses the exhaust gas flow path. The reformer 130 is accommodated in a direction in which the central axis of the reformer 130 is parallel to the central axis of the accommodation portion 310. In the section located in the exhaust gas flow path of the reformer 130, a plurality of catalyst units 200 carrying a catalyst are stacked and accommodated in a direction crossing the exhaust gas flow path.

[0096] According to such a structure, the heat of the exhaust gas flowing into the inside of the storage housing 300 can uniformly heat the outer peripheral surface of the reformer 130. The outer peripheral surface of the reformer 130 is heated over the entire circumference. In addition, the catalyst units 200 stacked and accommodated in the reformer 130 can be heated up with high uniformity. Since the reforming reaction for each catalyst unit 200 can proceed uniformly, the reforming rate of the mixed gas as a whole can be improved.

[0097] The plurality of reformers 130 are stored one by one in a single storage section 310. The plurality of reformers 130 are arranged so as to cross the exhaust gas flow paths inside the storage housing 300 in parallel with each other. According to such a structure, the outer peripheral surfaces of the plurality of reformers 130 can be heated with high uniformity among the reformers 130 by the heat of the exhaust gas flowing into the inside of the storage housing 300. Since the plurality of reformers 130 can be used at once, the production amount of the reformed gas can be increased and the heat of the exhaust gas can be effectively utilized.

[0098] The reformer 130 is detachably provided with respect to the storage housing 300. The reformer 130 can be inserted and removed in the longitudinal direction with respect to the storage section 310 when the reformer 130 is installed or replaced. After the reformer 130 is inserted into the storage section 310, it is fixed by a fixing mechanism using a shaft sealing member with respect to the storage section 310. Pipes are connected to the inlet connection section 307 and the outlet connection section 308 of the reformer 310 stored in the storage section 310.

[0099] The exhaust gas discharged from the gas engine 110 flows, after being discharged from the duct that discharges the exhaust gas of the superheater 121, through the inside of the storage housing 300 and into the duct that sucks the exhaust gas of the evaporator 122. During this time, the outer peripheral surface of the reformer 130 stored in the storage section 310 is heated by the exhaust gas. The catalyst inside the reformer 130 is heated at a higher heating rate compared to the case where a mixed gas is introduced into the reformer 130 to raise the temperature until it reaches near the optimum temperature for the reforming reaction.

[0100] The exhaust gas boiler 120 equipped with such a storage housing 300 can be provided for cogeneration applications by unitizing the superheater 121, the storage housing 300 in which the reformer 130 is stored, and the evaporator 122. By performing unitization, it becomes possible to operate the functions of the exhaust gas boiler 120 and the reformer 130 integrally, and a compact system capable of quickly starting the reformer 130 can be obtained.

[0101] FIG. 7 is a diagram showing a fixing mechanism for fixing a reformer to a storage housing. FIG. 8A is a cross-sectional view of a reformer provided with a stopper. FIG. 8B is a plan view and a cross-sectional view of a packing receiving jig. FIG. 8C is a plan view and a cross-sectional view of a packing presser. FIG. 8D is a plan view of a special washer. In FIGS. 7, 8A, 8B, and 8C, reference numeral 401 denotes a stopper, reference numeral 402 denotes a packing receiving jig, reference numeral 403 denotes a packing presser, reference numeral 404 denotes a special washer, and reference numeral 410 denotes a gland packing.

[0102] As shown in FIG. 7, the storage housing 300 includes a fixing mechanism for fixing the reformer 130. The reformer 130 stored in the storage housing 300 is fixed to the storage portion 310 of the storage housing 300 by a fixing mechanism using a shaft sealing member. As the shaft sealing member, a gland packing 410 is used. The fixing mechanism is composed of a stopper 401, a packing receiving jig 402, a packing presser 403, a special washer 404, a gland packing 410, and parts of the reformer 130 and the storage housing 300.

[0103] As shown in FIG. 8A, the stopper 401 is provided in a protruding shape that protrudes outward from the outer peripheral surface on the outer peripheral surface of the container portion 131 of the reformer 130. The stopper 401 is formed by joining a square bar or the like to the outer peripheral surface of the container portion 131. The stopper 401 has a receiving surface facing the outside of the storage portion 310.

[0104] As shown in FIG. 7, the stopper 401 is arranged such that in the longitudinal direction of the storage portion 310, the receiving surface facing the outside is at a position separated by a predetermined distance from the inlet side surfaces 303, 305 of the storage housing 300 and the flange 312 of the storage portion 310. The stopper 401 stops a packing receiving jig 402 or the like packed between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130 at a predetermined position in the longitudinal direction of the storage portion 310.

[0105] In FIG. 8A, the stoppers 401 are provided at four positions on the outer peripheral surface of the container portion 131 of the reformer 130 at a pitch of 90 degrees. However, the stoppers 401 can be provided in an appropriate number and at an appropriate pitch. Also, they can be provided at an appropriate length in the longitudinal direction of the storage portion 310.

[0106] As shown in FIG. 8B, the packing receiving jig 402 is provided in a split annular plate shape. The packing receiving jig 402 is used by being combined so that the divided units face each other. The inner diameter of the packing receiving jig 402 is provided to be equal to or slightly larger than the outer diameter of the container portion 131 of the reformer 130. The outer diameter of the packing receiving jig 402 is provided to be equal to or slightly smaller than the inner diameter of the storage portion 310.

[0107] As shown in FIG. 7, the packing receiving jig 402 is arranged to contact the receiving surface of the stopper 401 in the longitudinal direction of the storage portion 310. The packing receiving jig 402 mechanically supports the ground packing 410 etc. packed between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130 by receiving it from the inside of the storage portion 310.

[0108] In FIG. 8B, the packing receiving jig 402 is provided with a split structure that splits into two. However, the packing receiving jig 402 can be provided with an appropriate split structure, shape, and size according to the arrangement of the stopper 401 etc.

[0109] As shown in FIG. 8C, the packing presser 403 is provided in a split cylindrical shape with a flange formed at one end. The packing presser 403 is used by being combined so that the divided units face each other. The inner diameter of the packing presser 403 is provided to be equal to or slightly larger than the outer diameter of the container portion 131 of the reformer 130. The outer diameter of the flange of the packing presser 403 is provided to match the outer diameter of the flange 312 of the storage portion 310.

[0110] As shown in FIG. 7, the packing retainer 403 is arranged to abut against the outer surface of the grand packing 410 and the outer surface of the flange 312 of the storage part 310 in the longitudinal direction of the storage part 310. The packing retainer 403 mechanically supports the grand packing 410 etc. packed between the inner peripheral surface of the container part 311 of the storage part 310 and the outer peripheral surface of the container part 131 of the reformer 130 by pressing it from the outside of the storage part 310.

[0111] Bolt holes 403a for flange connection to the flange 312 of the storage part 310 are provided in the flange of the packing retainer 403. In FIG. 8C, two bolt holes 403a are provided near both ends of the packing retainer 403 for each divided unit of the packing retainer 403. The packing retainer 403 is fixed to the flange 312 of the storage part 310 by flange connection using the bolt holes 403a.

[0112] In FIG. 8C, the packing retainer 403 is provided with a split structure that is split in two. However, the packing retainer 403 can be inserted into the gap between the inner peripheral surface of the container part 311 of the storage part 310 and the outer peripheral surface of the container part 131 of the reformer 130, and can be provided with an appropriate split structure, shape, and size as long as it can uniformly press the grand packing 410.

[0113] As shown in FIG. 8D, the special washer 404 is provided in a partial annular plate shape obtained by cutting out a partial arc of an annular shape. Two special washers 404 are used as a pair. The inner diameter and outer diameter of the special washer 404 can be provided to be the same as the inner diameter and outer diameter of the packing retainer 403.

[0114] As shown in FIG. 7, the special washer 404 is arranged to abut against the outer surface of the packing retainer 403 in the longitudinal direction of the storage part 310. The special washer 404 prevents loosening of the packing retainer 403. The special washer 404 is arranged and fixed so as to face in a direction orthogonal to the direction in which the divided units of the packing retainer 403 face each other. According to the special washer 404, loosening in the direction in which the divided units of the packing retainer 403 separate from each other is prevented.

[0115] The special washer 404 is provided with bolt holes 404a for bolt fastening to the flange 312 of the storage portion 310. In FIG. 8D, two bolt holes 404a are provided near both ends of the special washer 404. The special washer 404 is fixed to the flange 312 of the storage portion 310 by bolt fastening using the bolt holes 404a together with the packing retainer 403.

[0116] In FIG. 8D, the special washer 404 is provided in the same size as the packing retainer 403. However, the special washer 404 can be provided in an appropriate combined structure, shape, and size as long as it can connect and fix the divided units of the packing retainer 403. For example, the special washer 404 may be in a shape that fits the packing retainer 403 and may be provided in a structure that covers the outer surface and the outer peripheral surface of the packing retainer 403.

[0117] As shown in FIG. 7, the gland packing 410 is a gap between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130, and is packed between the packing receiving jig 402 and the packing retainer 403. The gland packing 410 functions as a shaft sealing member that hermetically seals this gap.

[0118] As the material of the gland packing 410, an appropriate sealing material such as carbon or polytetrafluoroethylene can be used. As the gland packing 410, either a molded body in which the sealing material is formed into a cylindrical shape or a braid of the sealing material may be used. The braid of the sealing material is wound in a coil shape at a location where shaft sealing is required.

[0119] The reformer 130 is fixed to the storage housing 300 in the following procedure. First, the reformer 130 is inserted into the storage portion 310 of the storage housing 300. Then, the packing receiving jig 402 and the ground packing 410 are packed into the gap between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130 in this order up to the position where they are stopped by the stopper 401. Next, the packing presser 403 is inserted into the gap where the ground packing 410 is packed.

[0120] Subsequently, the special washer 404 is disposed outside the packing presser 403, and the packing presser 403 and the special washer 404 are bolted to the flange 312 of the storage portion 310. When the packing presser 403 is fastened to the flange 312 of the storage portion 310, it applies pressure from the outside to the ground packing 410 packed in the gap. The ground packing 410 is distorted in the longitudinal direction and the radial direction of the storage portion 310 due to the pressure from the packing presser 403. As a result, the ground packing 410 is pressed against the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130.

[0121] According to such a fixing mechanism using the shaft sealing member, the gap between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130 is hermetically sealed by the pressure of the pressed ground packing 410. The exhaust gas flowing into the inside of the storage housing 300 can heat the outer peripheral surface of the reformer 130 without leaking to the outside through the gap between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130.

[0122] As shown in FIGS. 8C and 8D, a pair of special washers 404 are arranged so as to face each other in a direction orthogonal to the direction in which the divided units of the packing retainer 403 face each other. The special washers 404 are stacked on the packing retainer 403 in such an arrangement and bolted to the flange 312 of the storage portion 310 together with the packing retainer 403. Therefore, the loosening in the direction in which the divided units of the packing retainer 403 separate from each other is prevented by the special washers 404 fixed in the intersecting directions. In the radial direction of the storage portion 310, since the displacement of the packing retainer 403 is suppressed, it becomes possible to obtain a highly uniform fastening force with each bolt. Therefore, the airtightness of the gap between the inner peripheral surface of the container portion 311 of the storage portion 310 and the outer peripheral surface of the container portion 131 of the reformer 130 can be improved.

[0123] After the reformer 130 is fixed to the storage housing 300 by such a fixing mechanism, it is connected to various piping systems. A mixed gas supply system for supplying a mixed gas in which city gas and superheated steam are mixed to the reformer 130 is connected to the connection pipe 133 at one end of the reformer 130. The mixed gas is generated by merging city gas for reforming reaction and superheated steam. A reformed gas supply system for supplying the reformed gas generated by the reformer 130 to the gas engine 110 is connected to the connection pipe 133 at the other end of the reformer 130.

[0124] A header device for equalizing the pressure of the mixed gas supplied from the mixed gas supply system can be connected to a plurality of reformers 130. When the header device is provided on the supply side, since the pressure of the mixed gas introduced into the plurality of reformers 130 is equalized, the reforming capacity of each reformer 130 can be leveled. Since each of the plurality of reformers 130 exhibits approximately the same reforming capacity as each other, it becomes possible to adjust the reforming capacity of the plurality of reformers 130 as a whole by the number of reformers 130 used.

[0125] A regulating valve for adjusting the flow rate of the mixed gas introduced for each reformer 130 can be connected to the plurality of reformers 130. When the regulating valve is provided on the supply side, the reforming capacity for each reformer 130 can be adjusted by changing the valve opening degree. Since the reforming capacity of each individual reformer 130 can be adjusted, it becomes possible to more precisely adjust the reforming capacity of the plurality of reformers 130 as a whole.

[0126] The reforming capacity of the plurality of reformers 130 as a whole may be adjusted only by the number of reformers 130 into which the mixed gas is introduced, or may be adjusted only by the opening degree of the regulating valve provided for each reformer 130, or may be adjusted by both of these. However, from the viewpoint of precisely adjusting the reforming capacity of the plurality of reformers 130 as a whole, it is preferable to provide a header device on the supply side of the plurality of reformers 130 and provide a regulating valve on the downstream side of the header device to adjust both.

[0127] FIG. 9 is a diagram showing the arrangement of a thermometer for measuring the temperature of the catalyst for the reforming reaction. As shown in FIG. 9, in the gas engine cogeneration device according to the present embodiment, the temperature of the catalyst for the reforming reaction is measured by the thermometer T when the reformer 130 is started or during the operation of the reformer 130.

[0128] The thermometer T measures the temperature of the catalyst layer 202 of the catalyst unit 200 housed in the reformer 130. The thermometer T can be installed at an appropriate location inside the reformer 130, inside the storage housing 300, etc. As the thermometer T, a contact type measuring instrument such as a thermocouple or a resistance thermometer, or a non-contact type measuring instrument such as an infrared radiation thermometer can be used.

[0129] The operation of the gas engine cogeneration device according to the present embodiment is performed in the following order.

[0130] First, start the gas engine 110 using city gas as fuel. The gas engine 110 is started and operated until it reaches the rated rotational speed using city gas supplied from a gas pipeline network or the like as fuel. Exhaust gas resulting from the combustion of city gas is discharged from the combustion chamber of the gas engine 110 toward the exhaust gas boiler 120.

[0131] The exhaust gas discharged from the gas engine 110 is exhausted in the order of the superheater 121 from the gas engine 110, the storage housing 300 from the superheater 121, and the evaporator 122 from the storage housing 300. During this process, the exhaust gas is utilized for generating superheated steam in the superheater 121 and the evaporator 122. Also, while the exhaust gas flows through the inside of the storage housing 300, it heats the reformer 130 stored in the storage unit 310. At this stage, the reforming reaction has not started and the introduction of the mixed gas to the reformer 130 is stopped.

[0132] The thermometer T measures the temperature of the catalyst layer 202 of the catalyst unit 200 stored in the reformer 130 after the gas engine 110 is started and before the start of the reforming reaction in the reformer 130. The temperature of the catalyst layer 202 is measured over time at a predetermined time interval. In the gas engine cogeneration device, the supply of superheated steam to the reformer 130 can be switched automatically or manually according to the temperature of the catalyst layer 202.

[0133] When starting the reformer 130, if the temperature of the catalyst layer 202 is less than 250°C, the introduction of superheated steam to the reformer 130 is not started, and the temperature increase of the reformer 130 by the exhaust gas is continued. In this case, for example, the valve of the mixed gas supply line for supplying the mixed gas to the reformer 130 and the valve of the superheated steam supply line for supplying superheated steam from the superheater 121 to the reformer 130 are closed.

[0134] On the other hand, when the temperature of the catalyst layer 202 is 250°C or higher, the introduction of superheated steam into the reformer 130 can be started. After heating the catalyst inside the reformer 130 to 250°C or higher with the exhaust gas, a mixed gas is supplied to the reformer 130 to generate the reaction products of the reforming reaction. In this case, for example, the valve of the mixed gas supply line for supplying the mixed gas to the reformer 130 and the valve of the superheated steam supply line for supplying superheated steam from the superheater 121 to the reformer 130 are opened.

[0135] Subsequently, the fuel of the gas engine 110 is switched from city gas to the mixed gas and then from the mixed gas to the reformed gas. In the process of switching the fuel, control to gradually decrease the supply flow rate of the city gas and control to gradually increase the supply flow rate of the reformed gas are performed synchronously. During the start-up operation at the rated rotational speed, control is performed to gradually increase the hydrogen concentration of the mixed gas until the reformed gas reaches a predetermined combustion power.

[0136] Subsequently, the gas engine 110 is operated at rated operation using the reformed gas as fuel. The reformed gas, which is the reaction product of the reforming reaction generated in the reformer 130, is supplied from the reformer 130 to the gas engine 110. The gas engine 110 is operated at the rated rotational speed using the reformed gas as fuel. The power generated by the gas engine 110 is used for power generation or the like to extract general power. The catalyst inside the reformer 130 is maintained at an appropriate reaction temperature by the exhaust gas discharged from the gas engine 110 and the superheated steam supplied from the exhaust gas boiler 120.

[0137] When stopping the gas engine 110, the fuel of the gas engine 110 is switched from the reformed gas to the mixed gas and then from the mixed gas to the city gas. In the process of switching the fuel, control to gradually decrease the supply flow rate of the reformed gas and control to gradually increase the supply flow rate of the city gas are performed synchronously. During the operation at the rated rotational speed, control is performed to decrease the supply flow rate of the reformed gas until the reformed gas in the combustion chamber and the piping is reduced to a completely combustible amount. Thereafter, the supply of the reformed gas to the gas engine 110 is stopped.

[0138] Subsequently, the combustion stroke in the gas engine 110 is stopped. In the process of stopping the gas engine 110, control is performed to gradually decrease the supply flow rate of the city gas. After the reformed gas in the combustion chamber and the piping is completely burned, the supply of the city gas to the gas engine 110 is stopped. Also, the supply of the mixed gas to the reformer 130 is stopped.

[0139] According to such operation, since the introduction of the superheated steam to the reformer 130 is switched according to the temperature of the catalyst layer 202, the catalyst carrier and the support material inside the reformer 130 do not come into contact with water at 200°C or lower. Since aluminum forming the catalyst carrier and the support material is less likely to cause a hydroxide reaction, it is possible to prevent the alteration, deformation of the catalyst carrier and the support material, and the blockage of the flow path inside the reformer 130.

[0140] Also, according to such operation, since the gas engine 110 is rated-operated using the reformed gas as fuel, it is possible to obtain high combustion efficiency while suppressing the overall consumption of the city gas. The total of the combustion energy (calorific value) increases with respect to the total weight of the supplied gas fuel, and the total of the combustion energy (calorific value) per unit supply amount of the gas fuel increases. Therefore, a gas engine cogeneration device with high combustion efficiency is realized.

[0141] Also, according to such operation, when the gas engine 110 is stopped, the fuel of the gas engine 110 is switched to the city gas. Since the fuel is switched from the reformed gas to the city gas, the remaining hydrogen in the combustion chamber and the piping is prevented. Therefore, the restart of the gas engine 110 after stopping can be surely and promptly performed using the high-concentration city gas not containing hydrogen as fuel.

[0142] The Cu-Zn-Cr catalyst described in Patent Document 2 has a narrow temperature range of 250 to 300°C for the reforming reaction. Therefore, when using such a catalyst, in order to avoid significant deterioration of the catalyst, it is necessary to provide a temperature control mechanism to control the temperature of the reforming reaction. The temperature range in which the catalyst undergoes significant deterioration and the temperature range that has a major impact on the strength of the reformer material need to be avoided by temperature control. In contrast, a reforming catalyst with an aluminum oxide catalyst support and a catalyst component such as a platinum group has a wide reaction temperature range of 250 to 500°C for the reforming reaction.

[0143] In the gas engine cogeneration device according to the present embodiment, since the catalyst is heated by the heat of the exhaust gas, when using a catalyst with such a wide reaction temperature range for the reforming reaction, the installation of a temperature control mechanism for controlling the reforming reaction within an appropriate temperature range can be omitted. Further, after the inside of the reformer 130 is heated to the optimum temperature for the reforming reaction, the mixed gas can be introduced into the reformer 130. Therefore, in the exhaust gas flow path discharged from the gas engine 110, a bypass for bypassing the reformer 130 becomes unnecessary.

[0144] As a result of verification by the present inventors, when the temperature of the catalyst layer inside the reformer is monitored and the reforming reaction is started by introducing the mixed gas after the temperature of the catalyst layer is raised to an appropriate temperature at which the aluminum hydroxide reaction does not occur, it was confirmed that even if aluminum is used as the catalyst material, the aluminum hydroxide reaction does not occur and the gas flow path inside the reformer does not become blocked. It was confirmed that it is possible to use an aluminum material that provides chemical stability, high thermal conductivity, etc.

[0145] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above-described embodiments, and various modifications are included as long as the technical scope is not deviated from. For example, the above-described embodiments are not necessarily limited to those having all the configurations described. Also, it is possible to replace a part of the configuration of one embodiment with another configuration, or add another configuration to the configuration of one embodiment. Further, it is also possible to add, delete, or replace a configuration of another configuration for a part of the configuration of one embodiment.

[0146] For example, the above-described gas engine cogeneration device uses city gas, reformed gas, or mixed gas as the fuel for the gas engine. However, as the gas fuel, other hydrocarbon-based fuels mainly composed of methane, reformed gas obtained by steam reforming thereof, or a mixed gas thereof may be used. As the gas fuel, LPG, CNG, biogas, etc., or a mixed gas thereof may be used. The operation method at the time of starting the gas engine is not limited to the above method.

[0147] Further, the above-described catalyst unit is provided as a cylindrical wound body, the above-described reformer is provided in a cylindrical shape, and the above-described storage housing is provided in a duct shape having a substantially rectangular cross section. However, the catalyst unit, reformer, and storage housing can be provided in an appropriate shape and structure as long as their functions are not impaired. Further, in the above-described catalyst unit, 250 ° C. with a margin is set as the upper limit of the temperature range to be avoided during catalyst heating. However, if there are other effective measures, other temperatures may be set as long as the hydroxylation reaction does not occur.

Explanation of Signs

[0148] 110 Gas engine 111 Generator 120 Exhaust gas boiler 121 Superheater 122 Evaporator 130 Reformer 131 Container part 132 Lid part 133 Connecting pipe 134 Connecting flange 140 Heat exchanger 200 Catalyst unit 201 Support material 202 Catalyst layer 300 Storage housing 301 Bottom surface part 302 Top surface part 303 Inlet side front part 304 Outlet side front part 305 Inlet side rear part 306 Outlet rear face part 307 Inlet connection part 308 Outlet connection part 309 Hanging tool 310 Storage part 401 Stopper 402 Packing receiving jig 403 Packing presser 404 Special washer 410 Ground packing

Claims

1. A gas engine cogeneration device comprising a reformer that takes in a mixed gas containing a gas fuel and superheated steam and generates a reaction product that becomes a reformed fuel through a catalyst, wherein the gas engine cogeneration device, comprises a housing that houses the reformer, a gas engine, a generator driven by the gas engine, and an exhaust gas boiler heated by exhaust gas from the gas engine, wherein the housing is disposed at an intermediate position between a superheater and an evaporator inside the exhaust gas boiler, and the superheated steam generated by the superheater is supplied to the reformer. A gas engine cogeneration device characterized by the above.

2. The gas engine cogeneration device according to claim 1, wherein the housing, comprises an inlet connection portion connected to the superheater and taking in the exhaust gas into the housing, an outlet connection portion connected to the evaporator and discharging the exhaust gas from inside the housing, a storage portion that stores the reformer, and a fixing mechanism that fixes the reformer to the storage portion. A gas engine cogeneration device characterized by the above.

3. The gas engine cogeneration device according to claim 2, wherein the storage portion is provided in a structure that crosses the exhaust gas flow path inside the housing, the reformer is in a container shape stored so as to cross the exhaust gas flow path with respect to the storage portion, and in a section of the reformer located in the exhaust gas flow path, a plurality of catalyst units carrying the catalyst are stacked and stored in a direction crossing the exhaust gas flow path. A gas engine cogeneration device characterized by the above.

4. The gas engine cogeneration device according to claim 3, wherein the housing comprises a plurality of the storage portions, the storage portions are arranged so as to cross the exhaust gas flow path in parallel with each other, and the reformer is stored one by one in one of the storage portions. A gas engine cogeneration device characterized by the above.

5. The gas engine cogeneration device according to claim 4, wherein the storage portions are arranged with intervals provided between the storage portions and between the storage portions and the inner wall of the exhaust gas flow path. A gas engine cogeneration device characterized by the above.

6. The gas engine cogeneration device according to claim 5, wherein: the catalyst unit has a catalyst layer carrying the catalyst; the reformer is provided with a thermometer for measuring the temperature of the catalyst layer; before the mixed gas is introduced into the reformer, the reformer is heated from the outer peripheral surface by passing the exhaust gas through the space, and when the temperature of the catalyst layer measured by the thermometer is 250°C or higher, the mixed gas is supplied to the reformer characterized gas engine cogeneration device.

7. A method for operating a gas engine cogeneration device including a reformer that takes in a mixed gas containing a gas fuel and superheated steam and generates a reaction product that becomes a reformed fuel through a catalyst, wherein the gas engine cogeneration device includes a housing that houses the reformer, a gas engine, a generator driven by the gas engine, and an exhaust gas boiler heated by the exhaust gas from the gas engine, the housing is disposed at an intermediate position between a superheater and an evaporator inside the exhaust gas boiler, and the superheated steam generated by the superheater is supplied to the reformer, the method for operating the gas engine cogeneration device exhausts the exhaust gas from the gas engine in the order of from the gas engine to the superheater, from the superheater to the housing, and from the housing to the evaporator, heats the reformer housed in the housing with the exhaust gas, supplies the mixed gas to the reformer to generate the reaction product, and supplies the reaction product to the gas engine to operate the gas engine characterized method for operating a gas engine cogeneration device.

8. A method for operating a gas engine cogeneration device according to claim 7, wherein the reformer includes a catalyst layer carrying the catalyst and a thermometer for measuring the temperature of the catalyst layer, heating the catalyst inside the reformer to 250°C or higher with the exhaust gas and then supplying the mixed gas to the reformer characterized method for operating a gas engine cogeneration device.

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