JP5496504B2 - Fuel cell system having hydrogen generators in multiple stages - Google Patents

Description

  The present invention relates to a fuel cell system provided with multiple stages of hydrogen generators.

  In recent years, carbon dioxide is one of the causative substances of global warming, and there is a strong demand for reducing carbon dioxide emissions. For this reason, development of fuel cells that do not generate carbon dioxide due to combustion is being promoted as a power supply source for factories, buildings, automobiles, homes, and the like. Hydrogen is used as a fuel for a fuel cell, and development of a fuel cell system in which an on-site type hydrogen production apparatus and a fuel cell are combined so that hydrogen of the fuel can be supplied at any time has become active.

  As a method for producing hydrogen, steam reforming reaction (steam reforming), autothermal reforming (ATR), partial oxidation and the like using a light hydrocarbon (for example, methane) as a raw material are known. For example, in steam reforming, carbon dioxide and water vapor are added to light hydrocarbons and reacted in the presence of a reforming catalyst in a heating furnace to produce a reformed gas mainly composed of hydrogen and carbon monoxide. Then, hydrogen is produced by separating hydrogen in the reformed gas. Steam reforming is an endothermic reaction, and the reaction requires a high temperature of 800 ° C. or higher. In addition, excess water vapor must be supplied to suppress carbon deposition. For this reason, large heat energy is required for the production of hydrogen.

  ATR is a method for synthesizing hydrogen by combining a light hydrocarbon oxidation reaction and a catalytic reaction. That is, carbon dioxide and water vapor are generated by the combustion of light hydrocarbons in the first stage of the reaction, and the reforming reaction of light hydrocarbons is performed in the catalytic reaction unit using carbon dioxide and water vapor generated as sequential reactions, and hydrogen and This is a method for producing hydrogen by producing a reformed gas mainly composed of carbon monoxide and then separating hydrogen in the reformed gas. In ATR, the reaction heat generated in the first stage can be propagated to the reforming reaction on the spot. Therefore, although the loss of heat energy is small compared to steam reforming, the reaction temperature is still high (1000 ° C or higher) Carbon generation is likely to occur in the generation part, and this carbon generation easily induces troubles in downstream devices of the catalyst part and the catalytic reaction part. In addition, the reaction requires high-purity and expensive oxygen, and the equipment cost and running cost are high.

The partial oxidation method burns part of light hydrocarbons by adding O ₂ and reforms the generated high-temperature gas without using a catalyst (no catalyst). It is. However, in the partial oxidation method, the reforming is performed at a temperature higher than ATR (about 1300 ° C.), and there is a problem that carbide is easily generated. In addition, the cooling method must be based on direct cooling (direct quench), and the operation operation becomes complicated. Furthermore, expensive oxygen of high purity is required, and the equipment cost and running cost are high.

The product gas obtained by the light hydrocarbon reforming method described above contains carbon monoxide and carbon dioxide in addition to hydrogen. For this reason, when hydrogen supply to a polymer electrolyte fuel cell (PEFC) is considered, a step of removing carbon monoxide and carbon dioxide from the generated gas is further required. Conventionally, in order to separate carbon monoxide and carbon dioxide from the product gas, a separation step such as decarboxylation after the shift reaction is required, which complicates the hydrogen generation step, and part of the hydrogen in the separation step. There is a problem that the efficiency of hydrogen generation is reduced.
In recent years, a method for generating high-purity hydrogen by reforming methane at a low temperature using a hydrogen generator equipped with a hydrogen permeable membrane has been proposed (for example, Non-Patent Document 1).
Tatsumi Ishihara, 3 others "New Reforming Process for H2 Production from Natural Gas by Using H2 Permanent Membrane Reactor", 15th World Hydrogen Energy Conference Preprint (CD-ROM), Lecture No. 200D-0628 Sun, Pacifico Yokohama Conference Center

However, in order to use hydrogen produced by reforming light hydrocarbons in a fuel cell, it is necessary to produce hydrogen with higher purity. In addition, in the fuel cell system using hydrogen generated by reforming light hydrocarbons, it is required to construct a more energy efficient system.
Therefore, the present invention is directed to a fuel cell system that can supply high-purity hydrogen to a fuel cell and has high energy efficiency.

  A fuel cell system according to the present invention includes a fuel cell, a catalyst combustion device that is filled with an oxidation catalyst and burns in contact with a combustible gas, a catalyst reaction chamber and a permeated hydrogen receiving chamber partitioned by a hydrogen permeable membrane. And a plurality of hydrogen generators in which the catalyst reaction chamber is filled with a hydrocarbon reforming catalyst (hereinafter sometimes simply referred to as a reforming catalyst), and combustion heat generated in the catalyst combustion device. A raw material preheating device that heats light hydrocarbons using, a means for supplying light hydrocarbons heated by the raw material preheating device to any of the catalytic reaction chambers, and oxygen using the combustion heat generated in the catalytic combustion device An oxygen preheating device for heating the fluid containing the fluid, means for supplying a fluid containing oxygen heated by the oxygen preheating device to any of the catalytic reaction chambers, and steam using the combustion heat generated in the catalytic combustion device A steam preheating device for heating; means for supplying the steam heated by the steam preheating device to any of the catalytic reaction chambers; and hydrogen supply means for supplying hydrogen generated by the hydrogen generator to the fuel cell. Hydrogen generated from light hydrocarbons in the catalytic reaction chamber of any of the hydrogen generators permeates through the permeated hydrogen receiving chamber partitioned by the hydrogen permeable membrane and separates from residual gas remaining in the catalytic reaction chamber. The residual gas is supplied to a catalytic reaction chamber of another hydrogen generator.

  It is preferable to have a water vapor supply means for supplying water vapor to the permeated hydrogen receiving chamber, more preferably, the water vapor supplying means supplies a part of the water vapor heated by the water vapor preheating device to the permeated hydrogen receiving chamber, Preferably, the hydrogen supply means has a pressure reducing unit that depressurizes the permeated hydrogen receiving chamber, and the residual gas remaining in the catalytic reaction chamber of the hydrogen generating device located most downstream in the hydrogen generating device is supplied to the catalytic combustion device. It is preferable to have a means for supplying water to the catalyst reaction chamber, and / or to have a water vapor generator for generating water vapor using hydrogen permeated to the permeated hydrogen receiving chamber as a heat source. The hydrogen receiving chamber is preferably filled with inert particles.

  According to the fuel cell system of the present invention, high-purity hydrogen can be supplied to the fuel cell, and energy efficiency can be improved.

The fuel cell system of the present invention will be described below with reference to examples. In addition, this invention is not limited to the following embodiment.
(First embodiment)
A fuel cell system according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic diagram of a fuel cell system 10. FIG. 2 is a cross-sectional view showing an example of a hydrogen generator used in the fuel cell system 10.

As shown in FIG. 1, the fuel cell system 10 includes a composite preheater 20, a catalytic combustion device 80, a first hydrogen generator 100, a second hydrogen generator 120, a steam generator 150, and a fuel cell 300. ing.
The raw material supply source 12 is connected to the composite preheater 20 by a pipe 14. A pipe 16 is connected to the pipe 14, and the pipe 16 is connected to a catalytic combustion device 80. A pipe 82 is connected to the catalytic combustion apparatus 80, and the pipe 82 is connected to the composite preheater 20.

  A pipe 32 is connected to the air supply source 30, and the pipe 32 is connected to a pipe 44 and a pipe 46 at a branch 45 via a second air blower 42. The piping 44 is connected to the catalytic combustion device 80, and the piping 46 is connected to the cathode 320 of the fuel cell 300. A pipe 34 is connected to the pipe 32, and the pipe 34 is connected to the composite preheater 20 via a first air blower 36.

  The composite preheater 20 is connected to the water vapor generating device 150 by a pipe 152. A pipe 23, a pipe 210, a pipe 220, and a pipe 240 are connected to the composite preheater 20. The pipe 210 is a flow path through which the air heated by the composite preheater 20 is circulated. The pipe 210 is branched into a pipe 212 and a pipe 214 at a branch 211, the pipe 212 is connected to the catalyst reaction chamber 116 of the first hydrogen generator 100, and the pipe 214 is connected to the pipe 117. The pipe 220 is a flow path for circulating light hydrocarbons heated by the composite preheater 20. The pipe 220 is connected to the pipe 212. The pipe 23 is a flow path through which the water vapor heated by the composite preheater 20 is circulated. The pipe 23 is connected to the pipe 230 and the pipe 250 at the branch 25. The pipe 230 is connected to the pipe 232 and the pipe 234 at the branch 233, the pipe 232 is connected to the permeated hydrogen receiving chamber 114 of the first hydrogen generator 100, and the pipe 234 is connected to the pipe 212. The pipe 250 is connected to the permeated hydrogen receiving chamber 124 of the second hydrogen generator 120 by a pipe 252. The pipe 240 is connected to the water vapor generator 150.

  A pipe 115 is connected to the permeated hydrogen receiving chamber 114, and the pipe 115 is connected to a pipe 118. The pipe 118 is connected to the water vapor generator 150. A pipe 117 is connected to the catalyst reaction chamber 116, and the pipe 117 is connected to the catalyst reaction chamber 126 of the second hydrogen generator 120. A pipe 128 is connected to the permeated hydrogen receiving chamber 124, and the pipe 128 is connected to the pipe 130. The pipe 130 is connected to the pipe 118. A pipe 132 is connected to the catalyst reaction chamber 126, and the pipe 132 is connected to the steam generator 150. The pipe 132 is provided with a gas turbine 134, and the gas turbine 134 is connected to a generator (not shown).

  A pipe 152, a pipe 154, a pipe 156, and a pipe 158 are connected to the steam generator 150. The pipe 152 is connected to the pipe 140 at a branch 153, and the pipe 140 is connected to the water softening device 60. The pipe 140 is provided with a steam turbine 142, and the steam turbine 142 is connected to a generator (not shown).

  The pipe 154 is connected to the gas-liquid separator 190 via the heat exchange device 155. A pipe 192 and a pipe 194 are connected to the gas-liquid separator 190. The pipe 192 is connected to the pipe 16, and the pipe 194 is connected to the water softening device 60. The pipe 158 is connected to the heat exchange device 160. A pipe 162, a pipe 166, and a pipe 68 are connected to the heat exchange device 160. The pipe 162 is connected to the hot water storage tank 164. A pipe 161 is connected to the pipe 162, and the pipe 161 is connected to the steam generator 150. The pipe 166 is connected to the gas-liquid separator 170. The pipe 68 is connected to the pipe 62 and the pipe 66 at a branch 67. A pipe 172 and a pipe 174 are connected to the gas-liquid separator 170. The pipe 172 is connected to the anode 330 of the fuel cell 300, and the pipe 174 is connected to the water softening device 60. The pipe 156 is connected to the heat exchange device 180. A pipe 182, a pipe 184, and a pipe 66 are connected to the heat exchange device 180. The pipe 182 is connected to the pipe 162, and the pipe 184 is connected to an exhaust port (not shown). The pipe 66 is connected to the pipe 62 and the pipe 68 at a branch 67. A pipe 52 and a pipe 62 are connected to the water softening device 60. The pipe 52 is connected to the water source 50, and the pipe 62 is connected to the pipe 64 at a branch 63.

  The pipe 64 is connected to the cooling unit 302 of the fuel cell 300. The cooling unit 302 is connected to the pipe 322, and the pipe 322 is connected to the pipe 162. A cathode offgas line 324 for discharging unreacted air is connected to the cathode 320. An anode off gas recycle line 334 for supplying unreacted hydrogen to the anode 330 again is connected to the anode 330, and the anode off gas recycle line 334 is connected to the pipe 172. An anode off gas recycle blower 336 is provided on the anode off gas recycle line 334.

  “Means for supplying light hydrocarbons heated by the raw material preheating device to any of the catalytic reaction chambers” includes pipes 220 and 212. “Means for supplying a fluid containing oxygen heated by the oxygen preheating device to any of the catalytic reaction chambers” includes pipes 210 and 212. “Means for supplying water vapor heated by the water vapor preheating device to any of the catalytic reaction chambers” includes pipes 23, 230, 234, and 212. One of the “steam supply means” includes the pipes 152, 23, 230, and 232, the steam generator 150, and the composite preheater 20. One of the “steam supply means” includes the pipes 152, 23, 250, 252, the steam generator 150, and the composite preheater 20. The “hydrogen supply means” includes pipes 115, 118, 128, 130, 158, 166, 172, a steam generator 150, a heat exchanger 160, and a gas-liquid separator 170. The “means for supplying residual gas to the catalytic combustion apparatus” includes pipes 16, 132, 154, 192, a gas turbine 134, a steam generator 150, a heat exchanger 155, and a gas-liquid separator 190. ing.

  The first hydrogen generator 100 generates hydrogen by bringing light hydrocarbons into contact with the reforming catalyst in the presence of oxygen and water vapor, and the remaining hydrogen, unreacted light hydrocarbons, and other components remain. The gas is separated by a hydrogen permeable membrane. Examples of the first hydrogen generator 100 include a plate type, a fixed bed type, and a fluidized bed type, and examples of the plate type include those shown in FIG. As shown in FIG. 2, the hydrogen generator 100 includes a main body 110 that is partitioned by a hydrogen permeable membrane 112 and has a catalytic reaction chamber 116 and a permeable hydrogen receiving chamber 114 that sandwiches the catalytic reaction chamber 116. A pipe 212 and a pipe 117 are connected to the catalyst reaction chamber 116, and a pipe 232 and a pipe 115 are connected to the permeated hydrogen receiving chamber 114, respectively. The catalyst reaction chamber 116 is filled with a reforming catalyst. The permeated hydrogen receiving chamber 114 is filled with inert particles (inert particles).

  As the hydrogen permeable membrane 112, a known hydrogen permeable membrane can be used, and examples thereof include a palladium (Pd) alloy membrane. Examples of commercially available hydrogen permeable membranes include Pd—Ag membranes and Pd—Cu (copper) membranes manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.

  The inert particles filled in the permeated hydrogen receiving chamber 114 are not particularly limited as long as they are inert to hydrogen, and examples thereof include alumina, zirconia, and silica. By filling the permeated hydrogen receiving chamber 114 with inert particles, the hydrogen generated in the catalytic reaction chamber 116 and transmitted through the hydrogen permeable membrane 112 to the permeated hydrogen receiving chamber 120 is supplied to the permeated hydrogen receiving chamber 114. This is because it is sufficiently mixed with the water vapor and can flow out of the permeated hydrogen receiving chamber 116 efficiently.

The reforming catalyst filled in the catalytic reaction chamber 116 generates hydrogen from light hydrocarbons in the presence of oxygen and water vapor. A known catalyst can be used as such a reforming catalyst. For example, Ni / SiO ₂ , Ni—Rh / SiO ₂ , Ni—Pt in which reactions of the following formulas (1) to (6) occur: Nickel-based catalysts such as / SiO ₂ and Ni—Fe / SiO ₂ are preferably used. This is because by using such a reforming catalyst, hydrogen can be generated from light hydrocarbons under a relatively low temperature condition of 500 to 700 ° C.

CH ₄ ⇒ C + 2H ₂ (1)
C _n H _{2n + 2} ⇒ nC + (n + 1) H ₂ (2)
C + (1/2) O ₂ ⇒CO (3)
_{C + H 2 O⇒H 2 + CO} ··· (4)
CH ₄ + H ₂ O⇔3H ₂ + CO (5)
CO + H ₂ O⇔H ₂ + CO ₂ (6)
[In the above formula (2), n is an integer of 2 or more. ]

  The second hydrogen generator 120 may be a plate type, a fixed bed type, a fluidized bed type, etc., like the first hydrogen generator 100. For example, the plate-type second hydrogen generator 120 is partitioned by the hydrogen permeable membrane 112 to form a catalytic reaction chamber 126 and a permeable hydrogen receiving chamber 124 that sandwiches the catalytic reaction chamber 126. A pipe 117 and a pipe 132 are connected to the catalyst reaction chamber 126, and a pipe 252 and a pipe 128 are connected to the permeated hydrogen receiving chamber 124, respectively. The catalyst reaction chamber 126 is filled with a reforming catalyst. The permeated hydrogen receiving chamber 124 is filled with inert particles. The inert particles filled in the permeated hydrogen receiving chamber 124 are the same as the inert particles filled in the permeated hydrogen receiving chamber 114. The reforming catalyst filled in the catalyst reaction chamber 126 is the same as the reforming catalyst filled in the catalyst reaction chamber 116.

  The composite preheater 20 includes an air heating unit 22, a water vapor heating unit 24, and a raw material heating unit 26. The composite preheater 20 is a device that takes in the combustion heat generated in the catalytic combustion device 80 and heats a fluid (air) containing light hydrocarbons, water vapor, and oxygen. In the present invention, the oxygen preheating device corresponds to the air heating unit 22, the steam preheating device corresponds to the steam heating unit 24, and the raw material preheating device corresponds to the raw material heating unit 26.

  The catalytic combustion device 80 is a device that supplies a combustible gas to a catalyst layer filled with an oxidation catalyst and burns it. The combustible gas is a light hydrocarbon used as the auxiliary gas and the residual gas in the catalytic reaction chamber 126 during steady operation of the fuel cell system 10. As the oxidation catalyst, a known oxidation catalyst can be used, and examples thereof include noble metals such as platinum, palladium, ruthenium, and rhodium, or those in which these noble metals are supported on a simple substance such as an alumina porous body.

  The steam generator 150 is a device that generates steam using the combustion gas of the catalytic combustion device 80 used as the heat medium in the composite preheater 20, the hydrogen separated from the hydrogen generator 100 and the residual gas as the heat medium. Examples of such a steam generator 150 include so-called composite boilers, flue boilers, once-through boilers, and the like.

The fuel cell 300 generates electricity using hydrogen as a fuel gas, and is a polymer electrolyte fuel cell (PEFC), an alkaline electrolyte fuel cell (AFC), a phosphoric acid fuel cell (PAFC), or a solid oxide fuel cell. Any of (SOFC) may be used. The fuel cell 300 is provided with a cathode 320 and an anode 330 so as to sandwich the electrolyte 310. The fuel cell 300 includes a cell having a pair of cathodes 320 and anodes 330, an electrolyte 310 sandwiched between the cathodes 320 and anodes 330, and the outside thereof sandwiched between separators to form a plurality of cells. It also includes a stacked fuel cell stack. The electrolyte 310 can be determined according to the type of the fuel cell 300.
The fuel cell 300 is provided with a cooling unit 302 for removing heat generated by power generation. Examples of the cooling unit 302 include a cooling plate and a cooling pipe that use cooling water as a heat medium. When the fuel cell 300 is a fuel cell stack, a plurality of cooling units 302 may be provided according to the amount of heat generated by the fuel cell stack.

  The gas-liquid separator 170 is not particularly limited, and examples thereof include a gas-liquid separator with a demister. The gas-liquid separator 190 is the same as the gas-liquid separator 170.

The water softening device 60 is a device that removes cation components such as Mg ²⁺ and Ca ²⁺ and anion components such as Cl ⁻ contained in water supplied from the water source 50. For example, an ion exchange device filled with a cation exchanger such as a cation exchange resin and an anion exchanger such as an anion exchange resin can be used.

  The air supply source 30 supplies a fluid containing oxygen, and examples thereof include an intake port that takes in air.

The operation of the fuel cell system 10 will be described.
The water from the water source 50 is supplied to the water softening device 60 via the pipe 52, and the water softening device 60 performs a softening process to remove hardness components. A part of the softened water is supplied to the steam generator 150 through the pipes 62 and 68, the heat exchange device 160, the pipe 162, and the pipe 161 in this order. Further, the other part of the softened water is supplied to the heat exchange device 180 via the pipes 62 and 66 in order. Further, another part of the softened water is supplied to the cooling unit 302 of the fuel cell 300 through the pipes 62 and 64 in order. The water supplied to the cooling unit 302 flows while cooling the fuel cell 300 and flows into the pipe 322 as hot water. The hot water flowing out to the pipe 322 is stored in the hot water storage tank 164 via the pipe 162.

  The first air blower 36 and the second air blower 42 are activated. Air is supplied to the cathode 320 from the air supply source 30 via the pipes 32 and 46 in order. Air is supplied to the catalytic combustion apparatus 80 from the air supply source 30 via the pipes 32 and 44 in order. Further, the air is supplied from the air supply source 30 to the air heating unit 22 of the composite preheater 20 via the pipes 32 and 34 in order. The air supplied to the air heating unit 22 is heated by the air heating unit 22 to become preheated air, and then flows into the pipe 210. Part of the preheated air that has flowed into the pipe 210 is supplied from the branch 211 to the catalytic reaction chamber 116 via the pipe 212. In addition, another part of the preheated air that has flowed into the pipe 210 flows from the branch 211 to the pipe 214.

  The light hydrocarbons are supplied from the raw material supply source 12 via the pipe 14 to the raw material heating unit 26 of the composite preheater 20. The light hydrocarbons supplied to the raw material heating unit 26 are heated by the raw material heating unit 26 to become preheated light hydrocarbons, and then mixed with preheated air flowing through the pipe 212 via the pipe 220. Light hydrocarbons as auxiliary fuel are supplied as combustible gas from the raw material supply source 12 via the pipes 14 and 16 to the catalytic combustion apparatus 80 together with the remaining gas. The combustible gas supplied to the catalytic combustion device 80 comes into contact with the oxidation catalyst filled in the catalytic combustion device 80 and burns. The combustion gas generated by this combustion is supplied to the composite preheater 20 via the pipe 82. The combustion gas supplied to the composite preheater 20 is used as a heat source for the air heating unit 22, the steam heating unit 24, and the raw material heating unit 26, and then supplied to the steam generating device 150 via the pipe 240.

  The steam generated by the steam generator 150 is supplied to the steam heating unit 24 via the pipe 152. The water vapor supplied to the water vapor heating unit 24 is heated by the water vapor heating unit 24 and flows into the pipe 23 as preheated water vapor. Part of the preheated water vapor that has flowed to the pipe 23 is flowed from the branch 25 to the pipe 230, and the preheated water vapor that has flowed to the pipe 230 is flowed from the branch 233 to the pipe 234, and preheated air that flows through the pipe 212 Mixed with. Further, a part of the preheated water vapor that has flowed to the pipe 230 flows from the branch 233 to the pipe 232 and is supplied to the permeated hydrogen receiving chamber 114 as sweep steam. Another part of the preheated water vapor that has flowed through the pipe 23 flows from the branch 25 to the pipe 250, and is supplied to the permeate hydrogen receiving chamber 124 via the pipe 252 as sweep steam.

  In the pipe 212, the preheated light hydrocarbon, the preheated air, and the preheated steam are mixed to become a mixed raw material. The mixed raw material is supplied to the catalytic reaction chamber 116. The supplied mixed raw material flows through the catalyst reaction chamber 116 adjusted to a predetermined temperature while being in contact with the reforming catalyst. In the meantime, the preheated light hydrocarbon generates hydrogen by the reaction of the following formulas (1) to (6), for example, in the presence of oxygen and water vapor.

CH ₄ ⇒ C + 2H ₂ (1)
C _n H _{2n + 2} ⇒ nC + (n + 1) H ₂ (2)
C + (1/2) O ₂ ⇒CO (3)
_{C + H 2 O⇒H 2 + CO} ··· (4)
CH ₄ + H ₂ O⇔3H ₂ + CO (5)
CO + H ₂ O⇔H ₂ + CO ₂ (6)
[In the above formula (2), n is an integer of 2 or more. ]

  Hydrogen generated in the catalytic reaction chamber 116 passes through the hydrogen permeable membrane 112 of the first hydrogen generator 100 and moves to the permeated hydrogen receiving chamber 114. The hydrogen moved to the permeated hydrogen receiving chamber 114 is mixed with the preheated water vapor supplied to the permeated hydrogen receiving chamber 114 via the pipe 232 and flows out from the pipe 115 as a hydrogen-containing fluid. The hydrogen-containing fluid is supplied to the steam generator 150 via the pipes 115 and 118. On the other hand, unreacted light hydrocarbons that cannot permeate the hydrogen permeable membrane 112, carbon dioxide, water, etc., and residual gas containing hydrogen that has not permeated the hydrogen permeable membrane 112 flow out of the pipe 117.

  The residual gas that has flowed out is mixed with the preheated air that has flowed through the pipe 214 to form a mixed fluid, and is supplied to the catalytic reaction chamber 126. The light hydrocarbons contained in the mixed fluid generate hydrogen in the catalytic reaction chamber 126 in the presence of oxygen and water vapor, for example, by the reactions of the above formulas (1) to (6). Then, the hydrogen generated in the catalytic reaction chamber 126 permeates the hydrogen permeable membrane 112 of the second hydrogen generator 120 and moves to the permeated hydrogen receiving chamber 124. The hydrogen moved to the permeated hydrogen receiving chamber 124 is taken into the preheated water vapor supplied to the permeated hydrogen receiving chamber 114 via the pipe 252 and flows out from the pipe 128 as a hydrogen-containing fluid. Then, the hydrogen-containing fluid is supplied to the steam generator 150 through the pipes 128, 130, and 118 in order. On the other hand, the residual gas containing unreacted light hydrocarbons, carbon dioxide, water, etc. that cannot permeate the hydrogen permeable membrane 112 of the second hydrogen generator 120, and hydrogen that has not permeated the hydrogen permeable membrane 112 is piped 132. Spill from. The residual gas that has flowed out of the catalytic reaction chamber 126 is supplied to the steam generator 150 via the pipe 132. During this time, the residual gas is generated by driving the gas turbine 134 provided in the pipe 132.

  The residual gas supplied to the steam generator 150 flows out of the pipe 154 after exchanging heat with water in the steam generator 150. The hydrogen-containing fluid supplied to the steam generator 150 flows out of the pipe 158 after exchanging heat with water in the steam generator 150. The combustion gas supplied to the steam generator 150 via the pipe 240 flows out of the pipe 156 after exchanging heat with water in the steam generator 150. During this time, water in the steam generator 150 becomes steam and flows out from the pipe 152. Of the steam generated by the steam generator 150, surplus steam generates electricity by driving the steam turbine 142 via the pipes 152 and 140.

  The residual gas flowing out from the pipe 154 is cooled to, for example, room temperature by the heat exchange device 155, and then separated into a gas component containing light hydrocarbons and water by the gas-liquid separation device 190. The gas component of the separated residual gas reaches the pipe 16 via the pipe 192 and is supplied to the catalytic combustion apparatus 80. On the other hand, the separated water is supplied to the water softening device 60 via the pipe 194 and softened. Here, when the gas component separated from the residual gas can cover the amount of heat necessary for the catalytic combustion device 80, the supply of light hydrocarbons for auxiliary fuel from the raw material supply source 12 can be stopped.

  The combustion gas flowing out from the pipe 156 is sent to an exhaust port (not shown) through the heat exchange device 180 through the pipe 184. During this time, the heat exchange device 180 exchanges heat with the water supplied from the pipe 66. And water turns into warm water of arbitrary temperature (for example, 60-70 degreeC), and is stored in the warm water storage tank 164 through piping 182 and 162 in order. The hydrogen-containing fluid flowing out from the pipe 158 is heat-exchanged with the water supplied from the pipe 68 by the heat exchange device 160, cooled to a predetermined temperature, and then supplied to the gas-liquid separator 170 by the pipe 166. The heat-exchanged water becomes warm water having an arbitrary temperature (for example, 60 to 70 ° C.) and reaches the warm water storage tank 164 via the pipe 162. The hydrogen-containing fluid supplied to the gas-liquid separator 170 is separated into water and hydrogen which is a gas component. The separated hydrogen is supplied to the anode 330 through the pipe 172. On the other hand, the separated water is supplied to the water softening device 60 through the pipe 174 and softened.

  When air is supplied to the cathode 320 and hydrogen is supplied to the anode 330, a chemical reaction such as the following formula (7) occurs at the cathode 320, and a chemical reaction such as the following formula (8) occurs at the anode 330. Power generation is performed.

(1/2) O ₂ + 2H ⁺ + 2e ⁻ → H ₂ O (7)
H ₂ ⇒2H ⁺ + 2e ⁻ (8)

  Then, the anode off-gas recycle blower 336 is activated, and unreacted hydrogen in the anode 330 is supplied to the anode 330 via the anode off-gas recycle line 334 and the pipe 172 in this order. The water produced at the cathode 320 is discharged from the cathode offgas line 324 together with the unreacted air in the cathode 320.

  Light hydrocarbon refers to natural gas, oil field associated gas, LPG, and the like, and indicates a hydrocarbon having 1 to 5 carbon atoms.

The temperature of the preheated light hydrocarbon at the outlet of the composite preheater 20 can be determined according to the type of reforming catalyst used in the hydrogen generator 100 and the hydrogen generator 120 and the type of the hydrogen permeable membrane 112. It is preferable to set it to -500 degreeC, and it is more preferable to set it as 350-450 degreeC.
The temperature of the preheated water vapor at the outlet of the composite preheater 20 can be determined according to the type of reforming catalyst used in the hydrogen generator 100 and the hydrogen generator 120 and the type of the hydrogen permeable membrane 112, and is 300 to 500. It is preferable to set it as ° C, and it is more preferable to set it as 350-450 ° C.
The temperature of the preheated air at the outlet of the composite preheater 20 can be determined according to the type of reforming catalyst used in the hydrogen generator 100 and the hydrogen generator 120 and the type of the hydrogen permeable membrane 112, and is 300 to 500. It is preferable to set it as ° C, and it is more preferable to set it as 350-450 ° C.

  The mixing ratio of light hydrocarbons, water vapor, and air in the mixed raw material supplied to the catalytic reaction chamber 116 can be determined according to the type of reforming catalyst charged in the catalytic reaction chamber 116. For example, the mixing ratio of the water vapor in the mixed raw material is preferably 1.0 to 2.0 in the S / C ratio represented by the number of moles of water vapor / the number of moles of light hydrocarbon carbon. Further, the mixing ratio of air in the mixed raw material can be determined in consideration of the carbon number of the light hydrocarbon, and is expressed by the molar ratio of oxygen in the mixed raw material / the molar ratio of light hydrocarbon carbon. The / C ratio is preferably 0.2 to 0.5.

  The amount of air supplied from the piping 214 to the piping 117 can be determined in consideration of the amount of light hydrocarbons and water vapor in the residual gas generated in the catalytic reaction chamber 116.

  The pressure of the mixed raw material supplied to the catalytic reaction chamber 116 is preferably determined in consideration of the type of the hydrogen permeable membrane 112, the type of reforming catalyst, and the like. For example, it is preferable to adjust the pressure of the mixed raw material supplied to the catalyst reaction chamber 116 so that the pressure of the residual gas at the outlet of the catalyst reaction chamber 116 is 744.3 to 844.3 kPa. The pressure of the mixed fluid supplied to the catalytic reaction chamber 126 is, for example, the pressure of the mixed fluid supplied to the catalytic reaction chamber 126 such that the pressure of the residual gas at the outlet of the catalytic reaction chamber 126 is 744.3 to 844.3 kPa. Is preferably adjusted.

  The supply amount of the preheated water vapor supplied to the permeate hydrogen receiving chamber 114 can be determined in consideration of the supply amount of the mixed raw material supplied to the catalytic reaction chamber 116. For example, the hydrogen partial pressure ratio represented by (hydrogen partial pressure of residual gas at the outlet of the catalytic reaction chamber) / (hydrogen partial pressure of hydrogen-containing fluid at the outlet of the permeated hydrogen receiving chamber) is 1.0 to 1.1. It is preferable to adjust so that. Within the above range, the hydrogen generated in the catalytic reaction chamber 116 can smoothly pass through the hydrogen permeable membrane 112, and the hydrogen generation efficiency is improved. The supply amount of preheated water vapor supplied to the permeated hydrogen receiving chamber 124 is the same as the supply amount of preheated water vapor supplied to the permeated hydrogen receiving chamber 114.

  The pressure of the preheated water vapor supplied to the permeated hydrogen receiving chamber 114 can be determined in consideration of the type of the hydrogen permeable membrane 112, the pressure in the catalytic reaction chamber 130, and the hydrogen partial pressure ratio, for example, 110 to 200 kPa. It is preferable to determine the range. Within the above range, hydrogen in the permeated hydrogen receiving chamber 114 can be efficiently pushed out of the permeated hydrogen receiving chamber 114, and the hydrogen partial pressure in the permeated hydrogen receiving chamber 114 can be maintained appropriately. And the hydrogen produced | generated in the catalytic reaction chamber 116 can permeate | transmit the hydrogen permeable film 112 smoothly, and the production | generation efficiency of hydrogen improves. The pressure of the preheated steam supplied to the permeated hydrogen receiving chamber 124 is the same as the pressure of the preheated steam supplied to the permeated hydrogen receiving chamber 114.

  The temperature of the catalytic reaction chamber 116 can be determined according to the type of reforming catalyst. For example, the temperature is preferably 500 to 700 ° C, and more preferably 500 to 650 ° C. It is because hydrogen can be efficiently generated from light hydrocarbons within the above range. The temperature of the catalytic reaction chamber 126 is the same as the temperature of the catalytic reaction chamber 116.

  The outlet temperature of the combustion gas generated in the catalytic combustion device 80 can be determined in consideration of the heat load of the composite preheater 20, the supply amount of light hydrocarbons, water vapor, air, etc., for example, 700 to 1000 ° C. It is preferable that

  Although the temperature of the water vapor | steam generated with the water vapor generator 150 is not specifically limited, For example, it is preferable to adjust in the range of 140-200 degreeC.

  The temperature of the hydrogen-containing fluid after cooling in the heat exchange device 160 can be determined according to the type of the fuel cell 300. For example, when PEFC is used as the fuel cell 300, the hydrogen-containing fluid is preferably cooled to 70 to 80 ° C. For example, when PAFC is used as the fuel cell 300, it is preferable to cool the hydrogen-containing fluid to 180 to 210 ° C.

  As described above, since a hydrogen generator that combines a catalytic reaction and a hydrogen permeable membrane is used, high-purity hydrogen can be obtained without providing new steps such as a shift reaction and a decarboxylation treatment. Then, by supplying the residual gas generated in the first hydrogen generator to the catalytic reaction chamber of the second hydrogen generator, hydrogen is efficiently generated from light hydrocarbons, and the amount of hydrogen supplied to the fuel cell Can be raised.

  The fuel cell system of the present embodiment is provided with water vapor supply means, supplies sweep steam to the permeate hydrogen receiving chamber, and forcibly pushes out the hydrogen that has permeated into the permeate hydrogen receiving chamber, so that the catalytic reaction chamber transfers to the permeate hydrogen receiving chamber. The permeation rate of hydrogen can be improved. In addition, by using preheated water vapor as the sweep steam supplied to the permeate hydrogen receiving chamber, the temperature of the hydrogen generator can be stabilized and hydrogen can be generated efficiently. As a result, hydrogen production efficiency can be improved.

  In the fuel cell system of this embodiment, the catalytic combustion apparatus can be operated using the residual gas separated by the hydrogen generator, so that the energy efficiency of the entire fuel cell system can be improved. In addition, since the steam is generated using the residual gas and the hydrogen-containing fluid, the thermal energy can be effectively used, and the energy efficiency of the entire fuel cell system can be improved. Furthermore, by filling the permeated hydrogen receiving chamber with inert particles, the hydrogen permeating the hydrogen permeable membrane and the water vapor flowing through the permeated hydrogen receiving chamber are rectified, and the hydrogen partial pressure / permeated hydrogen acceptance in the catalytic reaction chamber is rectified. The hydrogen partial pressure ratio expressed by the indoor hydrogen partial pressure can be kept appropriate. As a result, hydrogen production efficiency can be improved.

(Second embodiment)
A fuel cell system according to a second embodiment of the present invention will be described with reference to FIG. FIG. 3 is a schematic diagram of the fuel cell system 500. In addition, the same code | symbol is attached | subjected to the same component as the fuel cell system 10 of 1st embodiment, the description is abbreviate | omitted, and a different point is mainly demonstrated. That is, the fuel cell system 500 is different from the fuel cell system 10 in that high-purity oxygen (hereinafter sometimes referred to as pure oxygen) supplied from the oxygen supply source 510 is air supplied to the composite preheater 20. It is.

  The fuel cell system 500 has an oxygen supply source 510, and the oxygen supply source 510 is connected to the composite preheater 20 by a pipe 512. The oxygen supply source 510 supplies pure oxygen, and examples thereof include an air separation device. Further, for example, in order to use the surplus oxygen of the adjacent device, the oxygen supply source 510 may be a surplus oxygen storage tank or the like. 90 mass% or more is preferable and, as for the oxygen concentration of the pure oxygen supplied, 99% or more is more preferable.

  In the fuel cell system 500, pure oxygen is supplied from the oxygen supply source 510 to the air heating unit 22 of the composite preheater 20 via the pipe 512. The supplied pure oxygen is heated by the air heating unit 22 to become preheated oxygen, and flows into the pipe 210. Part of the preheated oxygen that has flowed to the pipe 210 is flowed from the branch 211 to the pipe 212 and mixed with the preheated light hydrocarbon supplied from the pipe 220 and the preheated steam supplied from the pipe 234 to be a mixed raw material. It becomes. Then, the mixed raw material is supplied to the catalytic reaction chamber 116 to generate hydrogen. Further, another part of the preheated oxygen that has flowed to the pipe 210 is flowed from the branch 211 to the pipe 214.

  The temperature of the preheated oxygen at the outlet of the composite preheater 20 can be determined according to the type of reforming catalyst filled in the catalytic reaction chamber 116 of the first hydrogen generator 100 and the type of the hydrogen permeable membrane 112. 300 to 500 ° C. is preferable, and 350 to 450 ° C. is more preferable.

  According to the fuel cell system of this embodiment, since the catalytic reaction is performed in the presence of pure oxygen in the catalytic reaction chamber, the efficiency of hydrogen generation can be improved.

(Third embodiment)
A fuel cell system according to a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is a schematic diagram of the fuel cell system 600.

As shown in FIG. 4, the fuel cell system 600 includes a composite preheater 20, a catalytic combustion device 80, a first hydrogen generator 620, a second hydrogen generator 630, a steam generator 150, a fuel cell 300, and a decompression unit 642. And have.
The raw material supply source 12 is connected to the composite preheater 20 by a pipe 14. A pipe 16 is connected to the pipe 14, and the pipe 16 is connected to a catalytic combustion device 80. A pipe 82 is connected to the catalytic combustion apparatus 80, and the pipe 82 is connected to the composite preheater 20.

  A pipe 32 is connected to the air supply source 30, and the pipe 32 is connected to a pipe 44 and a pipe 46 at a branch 45 via a second air blower 42. The piping 44 is connected to the catalytic combustion device 80, and the piping 46 is connected to the cathode 320 of the fuel cell 300. A pipe 34 is connected to the pipe 32, and the pipe 34 is connected to the composite preheater 20 via a first air blower 36.

  The composite preheater 20 is connected to the water vapor generating device 150 by a pipe 152. A pipe 610, a pipe 210, a pipe 220, and a pipe 240 are connected to the composite preheater 20. The pipe 210 is branched into a pipe 212 and a pipe 214 at a branch 211, the pipe 212 is connected to the catalyst reaction chamber 626 of the first hydrogen generator 620, and the pipe 214 is connected to the pipe 117. The pipe 220 is connected to the pipe 212. The pipe 610 is connected to the pipe 212. The pipe 240 is connected to the water vapor generator 150.

  A piping 115 is connected to the permeated hydrogen receiving chamber 624, and the piping 115 is connected to a piping 118. The pipe 118 is connected to the water vapor generator 150. A pipe 117 is connected to the catalyst reaction chamber 626, and the pipe 117 is connected to the catalyst reaction chamber 636 of the second hydrogen generator 630. A pipe 128 is connected to the permeated hydrogen receiving chamber 634, and the pipe 128 is connected to the pipe 130. The pipe 130 is connected to the pipe 118. A pipe 132 is connected to the catalyst reaction chamber 636, and the pipe 132 is connected to the steam generator 150. The pipe 132 is provided with a gas turbine 134, and the gas turbine 134 is connected to a generator (not shown).

A pipe 152, a pipe 154, a pipe 156 and a pipe 640 are connected to the steam generator 150. The pipe 152 is connected to the pipe 140 at a branch 153, and the pipe 140 is connected to the water softening device 60. The pipe 140 is provided with a steam turbine 142, and the steam turbine 142 is connected to a generator (not shown).
The pipe 154 is connected to the gas-liquid separator 190 via the heat exchange device 155. A pipe 192 and a pipe 194 are connected to the gas-liquid separator 190. The pipe 192 is connected to the pipe 16, and the pipe 194 is connected to the water softening device 60. The pipe 640 is connected to the gas-liquid separation device 170 via the heat exchange device 641 and the decompression unit 642. A pipe 172 and a pipe 174 are connected to the gas-liquid separator 170. The pipe 172 is connected to the anode 330 of the fuel cell 300, and the pipe 174 is connected to the water softening device 60. The pipe 156 is connected to the heat exchange device 180. A pipe 182, a pipe 184, and a pipe 662 are connected to the heat exchange device 180. The pipe 182 is connected to the pipe 684 and the pipe 686 at the branch 682. The pipe 684 is connected to the hot water storage tank 164, and the pipe 686 is connected to the water vapor generator 150. The pipe 184 is connected to an exhaust port (not shown). The pipe 662 is connected to the water softening device 60. Further, the pipe 662 is connected to the pipe 64 at a branch 663. The water softening device 60 is connected to the water source 50 by a pipe 52.

  The pipe 64 is connected to the cooling unit 302 of the fuel cell 300. The cooling unit 302 is connected to the pipe 322, and the pipe 322 is connected to the pipe 684. A cathode offgas line 324 for discharging unreacted air is connected to the cathode 320. An anode off gas recycle line 334 for supplying unreacted hydrogen to the anode 330 again is connected to the anode 330, and the anode off gas recycle line 334 is connected to the pipe 172. An anode off gas recycle blower 336 is provided on the anode off gas recycle line 334.

  “Means for supplying light hydrocarbons heated by the raw material preheating device to any of the catalytic reaction chambers” includes pipes 220 and 212. “Means for supplying a fluid containing oxygen heated by the oxygen preheating device to any of the catalytic reaction chambers” includes pipes 210 and 212. “Means for supplying water vapor heated by the water vapor preheating device to any of the catalytic reaction chambers” includes pipes 212 and 610. The “hydrogen supply means” includes pipes 115, 118, 128, 130, 172, 640, a steam generator 150, a gas-liquid separator 170, a heat exchanger 641, and a decompression unit 642. The “means for supplying residual gas to the catalytic combustion apparatus” includes pipes 16, 132, 154, 192, a gas turbine 134, a steam generator 150, a heat exchanger 155, and a gas-liquid separator 190. ing.

  The first hydrogen generator 620 includes a plate type, a fixed bed type, a fluidized bed type, and the like, similar to the first hydrogen generator 100 in the first embodiment. For example, the first hydrogen generator 620 is partitioned by the hydrogen permeable membrane 112 to form a catalytic reaction chamber 626 and a permeable hydrogen receiving chamber 624 that sandwiches the catalytic reaction chamber 626. The catalyst reaction chamber 626 is filled with a reforming catalyst. The permeate hydrogen receiving chamber 624 is filled with inert particles. The inert particles filled in the permeated hydrogen receiving chamber 624 are the same as the inert particles filled in the permeated hydrogen receiving chamber 114 in the first embodiment.

The reforming catalyst filled in the catalytic reaction chamber 626 generates hydrogen from light hydrocarbons in the presence of oxygen and water vapor. A known catalyst can be used as such a reforming catalyst. For example, Ni / SiO ₂ , Ni—Rh / SiO ₂ , Ni—Pt in which reactions of the following formulas (1) to (6) occur: Nickel-based catalysts such as / SiO ₂ and Ni—Fe / SiO ₂ are preferably used. This is because by using such a reforming catalyst, hydrogen can be generated from light hydrocarbons under a relatively low temperature condition of 500 to 700 ° C.

CH ₄ ⇒ C + 2H ₂ (1)
C _n H _{2n + 2} ⇒ nC + (n + 1) H ₂ (2)
C + (1/2) O ₂ ⇒CO (3)
_{C + H 2 O⇒H 2 + CO} ··· (4)
CH ₄ + H ₂ O⇔3H ₂ + CO (5)
CO + H ₂ O⇔H ₂ + CO ₂ (6)
[In the above formula (2), n is an integer of 2 or more. ]

  The second hydrogen generator 630 is the same as the first hydrogen generator 620. The reforming catalyst filled in the catalyst reaction chamber 636 is the same as the reforming catalyst filled in the catalyst reaction chamber 626. The inert particles filled in the permeable hydrogen receiving chamber 634 are the same as the inert particles filled in the permeable hydrogen receiving chamber 114 in the first embodiment.

  The decompression unit 642 is not particularly limited as long as the inside of the permeated hydrogen receiving chamber 624 and the permeated hydrogen receiving chamber 634 can be decompressed and sucked in hydrogen, and examples thereof include an IDF (Induced Draft Fan). . In addition, the decompression unit 642 may be configured by one IDF or the like, or may be configured by arranging two or more IDFs or the like in series.

The operation of the fuel cell system 600 will be described.
Water from the water source 50 is supplied to the water softening device 60 via the pipe 52 and softened. A part of the softened water is supplied to the heat exchange device 180 via the pipe 662. Further, another part of the softened water is supplied to the cooling unit 302 of the fuel cell 300 through the pipes 662 and 64 in order. The water supplied to the cooling unit 302 circulates while cooling the fuel cell 300 and flows out from the pipe 322 as hot water. The hot water flowing out to the pipe 322 is stored in the hot water storage tank 164 via the pipe 684.

  The 1st air blower 36, the 2nd air blower 42, and the pressure reduction part 642 are started. The preheated air heated by the air heating unit 22 is caused to flow through the pipe 210. A part of the preheated air that has flowed to the pipe 210 flows from the branch 211 to the pipe 212, and the other part flows to the pipe 214. The preheated steam heated by the steam heating unit 24 is mixed with preheated air in the pipe 212 via the pipe 610. The preheated light hydrocarbon heated in the raw material heating unit 26 is mixed with preheated air in the pipe 212 via the pipe 220. Thus, the preheated air, the preheated water vapor, and the preheated light hydrocarbon are mixed in the pipe 212 to be mixed and supplied from the pipe 212 to the catalytic reaction chamber 626. The mixed raw material supplied to the catalytic reaction chamber 626 flows through the catalytic reaction chamber 626 adjusted to a predetermined temperature while being in contact with the reforming catalyst. During this time, hydrogen is produced from the preheated light hydrocarbons by, for example, the reactions of the above formulas (1) to (6).

  The hydrogen generated in the catalytic reaction chamber 626 passes through the hydrogen permeable membrane 112 of the first hydrogen generator 620 and moves to the permeated hydrogen receiving chamber 624. The hydrogen moved to the permeated hydrogen receiving chamber 624 is sucked by the decompression unit 642 and supplied to the water vapor generating device 150 via the pipes 115 and 118. On the other hand, unreacted light hydrocarbons that cannot permeate the hydrogen permeable membrane 112, carbon dioxide, water, etc., and residual gas containing hydrogen that has not permeated the hydrogen permeable membrane 112 flow out of the pipe 117.

  The residual gas that has flowed out is mixed with the preheated air that has flowed through the pipe 214 to become a mixed fluid, and is supplied to the catalytic reaction chamber 636. The light hydrocarbons contained in the mixed fluid come into contact with the reforming catalyst in the presence of oxygen and water vapor in the catalytic reaction chamber 636 to generate hydrogen. Then, the hydrogen generated in the catalytic reaction chamber 636 passes through the hydrogen permeable membrane 112 of the second hydrogen generator 630 and moves to the permeable hydrogen receiving chamber 634. The hydrogen moved to the permeated hydrogen receiving chamber 634 is sucked by the decompression unit 642 and supplied to the water vapor generating device 150 through the pipes 128, 130, and 118 in order. On the other hand, the residual gas containing unreacted light hydrocarbons, carbon dioxide, water, etc. that cannot permeate the hydrogen permeable membrane 112 of the second hydrogen generator 630, and hydrogen that has not permeated the hydrogen permeable membrane 112 is pipe 132. And is supplied to the steam generator 150 through the pipe 132. During this time, the residual gas is generated by driving the gas turbine 134 provided in the pipe 132.

  The hydrogen supplied to the steam generator 150 flows out of the pipe 640 after exchanging heat with the water in the steam generator 150. The hydrogen flowing out from the pipe 640 is cooled to a predetermined temperature by the heat exchange device 641 and then supplied to the gas-liquid separation device 170 via the decompression unit 642. The hydrogen supplied to the gas-liquid separator 170 is dehumidified and supplied to the anode 330. Then, the fuel cell 300 generates power using the air supplied from the pipe 46 to the cathode 320 and the hydrogen supplied from the pipe 172 to the anode 330.

  The mixing ratio of light hydrocarbons, water vapor, and air in the mixed raw material supplied to the catalytic reaction chamber 626 can be determined according to the type of reforming catalyst charged in the catalytic reaction chamber 626. For example, the mixing ratio of the water vapor in the mixed raw material is preferably 1.0 to 2.0 in the S / C ratio represented by the number of moles of water vapor / the number of moles of light hydrocarbon carbon. Further, the mixing ratio of air in the mixed raw material can be determined in consideration of the carbon number of the light hydrocarbon, and is expressed by the molar ratio of oxygen in the mixed raw material / the molar ratio of light hydrocarbon carbon. The / C ratio is preferably 0.2 to 0.5.

  The amount of air supplied from the piping 214 to the piping 117 can be determined in consideration of the amount of light hydrocarbons and water vapor in the residual gas generated in the catalytic reaction chamber 116.

  The pressure of the mixed raw material supplied to the catalyst reaction chamber 626 is preferably determined in consideration of the type of the hydrogen permeable membrane 112, the type of reforming catalyst, and the like. For example, the residual gas pressure at the outlet of the catalyst reaction chamber 626 is preferably 247.3 to 520.3 kPa. In this embodiment, since the inside of the permeated hydrogen receiving chamber 624 is decompressed by the decompression unit 642, even if the pressure in the catalytic reaction chamber 626 is reduced, the hydrogen generated in the catalytic reaction chamber 626 causes the hydrogen permeable membrane 112 to flow. It is because it can penetrate smoothly. The pressure of the mixed fluid supplied to the catalyst reaction chamber 636 is the same as the pressure range of the mixed raw material supplied to the catalyst reaction chamber 626.

  The temperature of the hydrogen-containing fluid after cooling in the heat exchange device 641 can be determined according to the type of the fuel cell 300. For example, when PEFC is used as the fuel cell 300, the hydrogen-containing fluid is preferably cooled to 70 to 80 ° C. For example, when PAFC is used as the fuel cell 300, it is preferable to cool the hydrogen-containing fluid to 180 to 210 ° C.

The degree of pressure reduction of the permeated hydrogen receiving chamber 624 by the pressure reducing unit 642 is expressed by (hydrogen partial pressure of residual gas at the outlet of the catalytic reaction chamber) / (hydrogen partial pressure of hydrogen-containing fluid at the outlet of the permeated hydrogen receiving chamber). It is preferable to adjust the hydrogen partial pressure ratio to be 1.0 to 1.1. If it is in the said range, the hydrogen produced | generated in the catalyst reaction chamber 626 can permeate | transmit the hydrogen permeable film 112 smoothly, and the production | generation efficiency of hydrogen will improve. The degree of decompression of the permeated hydrogen receiving chamber 634 by the decompression unit 642 is adjusted so that the hydrogen partial pressure ratio in the hydrogen generator 630 is 1.0 to 1.1, similarly to the degree of decompression of the permeated hydrogen receiving chamber 624. It is preferable to do.
Further, the discharge pressure on the secondary side of the decompression unit 642 is preferably determined according to the operating conditions of the fuel cell 300.

  The temperature of the catalyst reaction chamber 626 is preferably 500 to 700 ° C, and more preferably 550 to 600 ° C. The temperature of the catalyst reaction chamber 636 is the same as the temperature range of the catalyst reaction chamber 626.

  As described above, in the present embodiment, the hydrogen in the permeate hydrogen receiving chamber is sucked by the decompression unit, so that (hydrogen partial pressure of residual gas at the outlet of the catalytic reaction chamber) / (hydrogen-containing fluid at the outlet of the permeate hydrogen receiving chamber) The hydrogen partial pressure ratio expressed by the following formula can be maintained appropriately. In addition, the heat energy for generating the sweep steam is not required, and the power generation efficiency of the fuel cell system can be improved. Furthermore, since the sweep steam is unnecessary, the water vapor generating device can be miniaturized and the fuel cell system can be miniaturized.

(Fourth embodiment)
A fuel cell system according to a fourth embodiment of the present invention will be described with reference to FIG. FIG. 5 is a schematic diagram of the fuel cell system 700. In addition, the same code | symbol is attached | subjected to the same component as the fuel cell system 600 of 3rd embodiment, the description is abbreviate | omitted, and a different point is mainly demonstrated. That is, the fuel cell system 700 is different from the fuel cell system 600 in that the air supplied to the composite preheater 20 is high-purity oxygen (hereinafter sometimes referred to as pure oxygen) supplied from the oxygen supply source 510. It is. That is, the fuel cell system 700 has an oxygen supply source 510, and the oxygen supply source 510 is connected to the composite preheater 20 by the pipe 512.

  In the fuel cell system 700, pure oxygen is supplied from the oxygen supply source 510 to the air heating unit 22 of the composite preheater 20 via the pipe 512. The supplied pure oxygen is heated by the air heating unit 22 to become preheated oxygen, and flows into the pipe 210. Part of the preheated oxygen that has flowed to the pipe 210 is passed from the branch 211 to the pipe 212 and mixed with the preheated light hydrocarbons supplied from the pipe 220 and the preheated steam supplied from the pipe 610 to be a mixed raw material. It becomes. Then, the mixed raw material is supplied to the catalytic reaction chamber 626 to generate hydrogen. Further, another part of the preheated oxygen that has flowed to the pipe 210 is flowed from the branch 211 to the pipe 214.

  According to the fuel cell system of this embodiment, since the catalytic reaction is performed in the presence of pure oxygen in the catalytic reaction chamber, the efficiency of hydrogen generation can be improved.

(Other embodiments)
The present invention is not limited to the above-described embodiment.
In the first to fourth embodiments, the permeation hydrogen receiving chamber is filled with inert particles, but the inert particles may not be filled. However, from the viewpoint of rectifying hydrogen and water vapor in the permeate hydrogen receiving chamber and improving the hydrogen generation efficiency, it is preferable to fill the permeate hydrogen receiving chamber with inert particles.

In the first to fourth embodiments, the gas turbine is provided on the secondary side of the second hydrogen generator, but the gas turbine may not be provided.
In the first to fourth embodiments, the steam turbine is provided in the pipe 140, but the steam turbine may not be provided.

  In the first to fourth embodiments, the hydrogen-containing fluid generated by the hydrogen generator, the residual gas, and the combustion gas generated by the catalytic combustion device and passing through the composite preheater are used as a heat source to generate water vapor. The heat source used in the apparatus may be only one of the aforementioned hydrogen-containing fluid, residual gas, and combustion gas.

  In the first to fourth embodiments, a raw material preheating device, an oxygen preheating device, and a steam preheating device are integrated, but the raw material preheating device, the oxygen preheating device, and the steam preheating device are individually provided. May be provided.

  In the first to fourth embodiments, two hydrogen generators are connected in series, but three or more hydrogen generators may be connected in series.

  In 1st-4th embodiment, the means to supply the preheated water vapor | steam heated with the composite preheater to a permeation hydrogen receiving chamber as a sweep steam is provided as a water vapor | steam supply means. However, the present invention is not limited to this, and the water vapor supply means may supply the water vapor generated by the water vapor generator to the permeate hydrogen receiving chamber without heating. From the viewpoint of stabilizing the temperature of the catalytic reaction chamber of the hydrogen generator and generating hydrogen efficiently, the steam supply means is means for supplying the preheated steam heated by the steam heating section to the permeate hydrogen receiving chamber as sweep steam. It is preferable.

  In the first and second embodiments, no decompression unit is provided, but a decompression unit may be further provided in the first and second embodiments. Alternatively, in the third and fourth embodiments, water vapor may be supplied to the permeate hydrogen receiving chamber as sweep steam.

  In 3rd, 4th embodiment, although the pressure reduction part is provided in one place, the pressure reduction part may be provided in two or more places. In addition, the decompression unit may be provided at any position of the hydrogen supply unit. For example, you may provide in the piping 172 (FIG. 3, 4) which is an exit line of the gas-liquid separator 170. FIG.

  EXAMPLES Hereinafter, although an Example is given and this invention is demonstrated concretely, it is not limited to an Example.

(Production Example 1) Manufacture of reforming catalyst 1 According to the description of Non-Patent Document 1 described above, Ni / SiO ₂ in which Ni is supported on SiO ₂ so as to be 10% by mass of the total mass of reforming catalyst 1 is manufactured. did. Nickel nitrate was used as a Ni supply source, and SiO ₂ (surface area: 380 m ² / g) manufactured by Aerosil Co. was used as a simple substance, and it was prepared by a known impregnation method. SiO ₂ was impregnated with an aqueous nickel nitrate solution and dried, followed by sintering at 300 ° C. for 4 hours and further heating at 400 ° C. for 5 hours to obtain a reforming catalyst 1.

Example 1
A fuel cell system A having the same configuration as the fuel cell system 10 shown in FIG. 1 was manufactured and a power generation test was performed.
The fuel cell stack of PEFC was adopted as the fuel cell, and the capacity of the test facility was set to 1.223 kW at the power generation end output (direct current) and 1 kW class as the power transmission end output (alternating current). The first hydrogen generator and the second hydrogen generator were plate types having the same structure as the hydrogen generator 100 shown in FIG. As the hydrogen permeable membrane of the first hydrogen generator, a commercially available Pd-Ag membrane (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was used, and its permeation area was 0.120 m ² . As the hydrogen permeable membrane of the second hydrogen generator, a commercially available Pd-Ag membrane (manufactured by Tanaka Kikinzoku Kogyo Co., Ltd.) was used, and its permeation area was 0.056 m ² . The catalytic reaction chamber of the first hydrogen generator was filled with 2.34 L of reforming catalyst 1. The catalyst reaction chamber of the second hydrogen generator was charged with 1.18 L of reforming catalyst 1. The permeated hydrogen receiving chamber of the first hydrogen generator was filled with 3.60 L of inert particles (alumina, mass average particle diameter: 5 mmφ, manufactured by Chipton Corporation). The permeated hydrogen receiving chamber of the second hydrogen generator was filled with 1.68 L of inert particles. The catalytic combustion apparatus was a fixed bed type, and was charged with 5.4 L of a palladium catalyst (hydrocarbon oxidation catalyst, manufactured by Zude Chemie Catalysts) as an oxidation catalyst. A composite boiler was used as the steam generator.

Natural gas was used as the light hydrocarbon of the raw material. The raw material natural gas was heated to 400 ° C. with a composite preheater and then supplied to the catalytic reaction chamber of the first hydrogen generator at 0.276 Nm ³ / h. After heating to 400 ° C. The air in composite preheater, 0.406Nm ³ / h in supplying preheated spent air to the catalytic reaction chamber of the first hydrogen generator, preheating already air second in ^0.187Nm 3 / h To the catalytic reaction chamber of the hydrogen generator. The first hydrogen generator using steam generated by the steam generator (temperature 170.6 ° C., pressure 803.3 kPa) to 400 ° C. with a combined preheater and preheated steam at 0.415 Nm ³ / h as process steam The preheated water vapor is supplied to the permeated hydrogen receiving chamber of the first hydrogen generator as a sweep steam at 0.828 Nm ³ / h, and the preheated water vapor is supplied to the second hydrogenated reactor at 0.583 Nm ³ / h. To the permeate hydrogen receiving chamber of the hydrogen generator.
The flow rate of natural gas as auxiliary fuel supplied to the catalytic combustion apparatus is 0.042 Nm ³ / h, and the combustion gas reference SV of the oxidation catalyst is 1848 (m ³ / h) / m ³ -Cat, The amount of heat transfer to the composite preheater was 1143 kJ / h (273 kcal / h).
Other process conditions were as shown in Table 1. “Nm ³ ” represents “m ³ (standard state)” (the same applies hereinafter). The “combustion gas standard SV” is the amount of combustion gas generated per hour (m ³ / h) per unit volume (m ³ -Cat) of the oxidation catalyst, and the unit (m ³ / h) / m ³ A value represented by -Cat (the same applies hereinafter).

The hydrogen generated in the catalytic reaction chamber of the first hydrogen generator is 0.514 Nm ³ / h, and the hydrogen permeated into the hydrogen permeation receiving chamber is 0.465 Nm ³ / h, and the hydrogen permeation flux is It was _{0.173kg-mol / h-H 2} / m 2. The hydrogen produced by the second hydrogen generator is 0.258 Nm ³ / h, and the hydrogen permeated into the hydrogen permeation receiving chamber is 0.217 Nm ³ / h, and the hydrogen permeation flux is 0.173 kg− They were ^{_{mol / h-H 2 / m}} 2. The total amount of hydrogen obtained in the first hydrogen generator and the second hydrogen generator was 0.682 Nm ³ / h. In addition, the value of the generated hydrogen reference W / F of the reforming catalyst 1 in the first hydrogen generator was 26.2 kg-Cat / kg-mol / h-H ₂ . The W / F value of the reforming catalyst 1 in the second hydrogen generator was 24.2 kg-Cat / kg-mol / h-H ₂ . The “hydrogen permeation flux” is the permeated hydrogen flow rate (kg-mol / h) per hour in the permeation membrane unit area (m ² ) (hereinafter the same). “W / F” is the amount of catalyst (kg-Cat) per hour of hydrogen production (kg-mol / h-H ₂ ), and kg-Cat / kg-mol / h-H ₂ Expressed (same in the following).

The value of the generated hydrogen corresponds to a raw material natural gas conversion rate of 54.5% for the first hydrogen generator, 21.2% for the second hydrogen generator, and a total of 75.7%. . Moreover, the sum total of the 1st hydrogen generator of the cold gas efficiency defined by the following (9) formula and the 2nd hydrogen generator was 71.2%. In the following formula (9), LHV (kJ / Nm ³ ) indicates a lower heating value.

Cold gas efficiency = (LHV of produced H ₂ + CO (Nm ³ / h)) / (LHV of supplied natural gas (Nm ³ / h)) × 100 (9)

  Thus, the fuel cell system A is operated, and the power generation efficiency of the fuel cell system A is measured. The results are shown in Table 1.

(Example 2)
A fuel cell system B having the same configuration as the fuel cell system 500 shown in FIG. 3 was manufactured and a power generation test was performed. The fuel cell, the first hydrogen generating device, the second hydrogen generating device, the catalytic combustion device, and the water vapor generating device all have the same specifications as in Example 1.

Natural gas was used as the light hydrocarbon of the raw material. Raw material natural gas 0.272 Nm ³ / h was heated to 400 ° C. with a composite preheater and then supplied to the catalytic reaction chamber of the first hydrogen generator. Pure oxygen (purity: 99.9% or more) is heated to 450 ° C. with a combined preheater, and then preheated oxygen is supplied to the catalytic reaction chamber of the first hydrogen generator at 0.084 Nm ³ / h. Preheated oxygen was supplied to the catalytic reaction chamber of the second hydrogen generator at ³ / h. The first hydrogen generator using steam generated at the steam generator (temperature 170.6 ° C., pressure 803.3 kPa) to 450 ° C. with a combined preheater and preheated steam at 0.409 Nm ³ / h as process steam It is supplied to the catalytic reaction chamber, supplying the permeated hydrogen acceptor chamber of the first hydrogen generator preheating already steam at 0.323Nm ³ / h as the sweep steam sweep steam preheating already steam at 0.156 nM ³ / h To the permeate hydrogen receiving chamber of the second hydrogen generator. Further, the supply of natural gas to the catalytic combustion apparatus as auxiliary fuel was not performed. The combustion gas reference SV in the catalytic combustion apparatus was 1034 (m ³ / h) / m ³ -Cat, and the heat transfer amount to the composite preheater was 741 kJ / h (177 kcal / h). Other process conditions were as shown in Table 1.

Hydrogen produced in the catalytic reaction chamber of the first hydrogen generator is 0.531 Nm ³ / h, and hydrogen permeated into the hydrogen permeation receiving chamber is 0.479 Nm ³ / h, and the hydrogen permeation flux is It was _{0.178kg-mol / h-H 2} / m 2. The hydrogen produced by the second hydrogen generator is 0.247 Nm ³ / h, and the hydrogen permeated into the hydrogen permeation receiving chamber is 0.203 Nm ³ / h, and the hydrogen permeation flux is 0.161 kg− It was ^{_{mol / h-H 2 / m}} 2. The total amount of hydrogen obtained in the first hydrogen generator and the second hydrogen generator was 0.682 Nm ³ / h. Moreover, the value of W / F of the reforming catalyst 1 in the first hydrogen generator was 25.4 kg-Cat / kg-mol / h-H ₂ . The W / F value of the reforming catalyst 1 in the second hydrogen generator was 25.4 kg-Cat / kg-mol / h-H ₂ .

  The value of the generated hydrogen corresponds to a raw material natural gas conversion rate of 56.8% for the first hydrogen generator, 20.4% for the second hydrogen generator, and a total of 77.2%. . Moreover, the sum total of the 1st hydrogen generator of the cold gas efficiency defined by the said (9) formula and the 2nd hydrogen generator was 73.6%. Thus, the fuel cell system B is operated, and the power generation efficiency of the fuel cell system B is measured. The results are shown in Table 1.

(Example 3)
A fuel cell system C having the same configuration as the fuel cell system 600 shown in FIG. 4 was manufactured and a power generation test was performed. Two turbo IDFs (hereinafter simply referred to as IDFs) were installed in series in the decompression unit. Of the two IDFs, the upstream side is the first IDF and the downstream side is the second IDF. The fuel cell, the first hydrogen generating device, the second hydrogen generating device, the catalytic combustion device, and the water vapor generating device all have the same specifications as in Example 1.

Natural gas was used as the light hydrocarbon of the raw material. The raw material natural gas 0.274 Nm ³ / h was heated to 400 ° C. with a composite preheater and then supplied to the catalytic reaction chamber of the first hydrogen generator. After heating to 400 ° C. The air in composite preheater, 0.402Nm ³ / h in supplying preheated spent oxygen to the catalytic reaction chamber of the first hydrogen generator, preheating already oxygen second in 0.181Nm ³ / h To the catalytic reaction chamber of the hydrogen generator. The first hydrogen generator using steam generated by the steam generator (temperature 170.6 ° C., pressure 803.3 kPa) to 400 ° C. with a combined preheater and preheated steam at 0.411 Nm ³ / h as process steam To the catalytic reaction chamber. Further, the supply of natural gas to the catalytic combustion apparatus as auxiliary fuel was not performed. The combustion gas reference SV in the catalytic combustion apparatus was 1208 (m ³ / h) / m ³ -Cat, and the heat transfer amount to the composite preheater was 599 kJ / h (143 kcal / h). The other process conditions are the values shown in Table 2, the first IDF and the second IDF are started, and the permeated hydrogen receiving chamber of the first hydrogen generating device and the permeated hydrogen receiving chamber of the second hydrogen generating device are depressurized. Then, the fuel cell system C was operated.

Hydrogen generated in the catalytic reaction chamber of the first hydrogen generator is 0.523 Nm ³ / h, and hydrogen permeated into the hydrogen permeation receiving chamber is 0.472 Nm ³ / h, and the hydrogen permeation flux is It was _{0.175kg-mol / h-H 2} / m 2. The hydrogen produced by the second hydrogen generator is 0.252 Nm ³ / h, and the hydrogen permeated into the hydrogen permeation receiving chamber is 0.210 Nm ³ / h, and the hydrogen permeation flux is 0.167 kg− It was ^{_{mol / h-H 2 / m}} 2. The total amount of hydrogen obtained in the first hydrogen generator and the second hydrogen generator was 0.682 Nm ³ / h. Moreover, the value of W / F of the reforming catalyst 1 in the first hydrogen generator was 25.8 kg-Cat / kg-mol / h-H ₂ . The W / F value of the reforming catalyst 1 in the second hydrogen generator was 24.9 kg-Cat / kg-mol / h-H ₂ .

  The value of the generated hydrogen corresponds to a raw material natural gas conversion rate of 55.6% for the first hydrogen generator, 20.6% for the second hydrogen generator, and a total of 76.2%. . Moreover, the sum total of the 1st hydrogen generator of the cold gas efficiency defined by the said (9) formula and the 2nd hydrogen generator was 74.4%. Thus, the fuel cell system C is operated, and the power generation efficiency of the fuel cell system C is measured. The results are shown in Table 2. In Table 2, the power consumption of the first air blower and the second air blower among the “accessory power consumption” is described as “air blower”. Moreover, the power consumption of 1st IDF and 2nd IDF described the total value as "IDF" (same in Example 4).

(Example 4)
A fuel cell system D having the same configuration as the fuel cell system 700 shown in FIG. 5 was manufactured and a power generation test was performed. Two IDFs were installed in series in the decompression unit. Of the two IDFs, the upstream side is the first IDF and the downstream side is the second IDF. The fuel cell, the first hydrogen generating device, the second hydrogen generating device, the catalytic combustion device, and the water vapor generating device all have the same specifications as in Example 1.

Natural gas was used as the light hydrocarbon of the raw material. The raw material natural gas 0.266 Nm ³ / h was heated to 400 ° C. with a composite preheater and then supplied to the catalytic reaction chamber of the first hydrogen generator. After heating the pure oxygen to 450 ° C. composite preheater, a preheat already oxygen at 0.082 nm ³ / h was supplied to the catalytic reaction chamber of the first hydrogen generator, preheating already oxygen 0.034Nm ³ / h the It was supplied to the catalytic reaction chamber of the second hydrogen generator. The first hydrogen generator using steam generated at the steam generator (temperature 170.6 ° C., pressure 803.3 kPa) to 450 ° C. with a combined preheater and preheated steam at 0.400 Nm ³ / h as process steam To the catalytic reaction chamber. Further, the supply of natural gas to the catalytic combustion apparatus as auxiliary fuel was not performed. The combustion gas reference SV in the catalytic combustion apparatus was 1053 (m ³ / h) / m ³ -Cat, and the heat transfer amount to the composite preheater was 507 kJ / h (121 kcal / h). The other process conditions are the values shown in Table 2, the first IDF and the second IDF are started, and the permeated hydrogen receiving chamber of the first hydrogen generating device and the permeated hydrogen receiving chamber of the second hydrogen generating device are depressurized. Then, the fuel cell system D was operated.

Hydrogen produced in the catalytic reaction chamber of the first hydrogen generator is 0.552 Nm ³ / h, and hydrogen permeated into the hydrogen permeation receiving chamber is 0.497 Nm ³ / h, and the hydrogen permeation flux is It was _{0.185kg-mol / h-H 2} / m 2. The hydrogen produced by the second hydrogen generator is 0.232 Nm ³ / h, and the hydrogen permeated into the hydrogen permeation receiving chamber is 0.185 Nm ³ / h, and the hydrogen permeation flux is 0.148 kg− It was ^{_{mol / h-H 2 / m}} 2. The total amount of hydrogen obtained in the first hydrogen generator and the second hydrogen generator was 0.682 Nm ³ / h. Moreover, the value of W / F of the reforming catalyst 1 in the first hydrogen generator was 24.4 kg-Cat / kg-mol / h-H ₂ . The value of W / F of reforming catalyst 1 in the second hydrogen generator was 27.1 kg-Cat / kg-mol / h-H ₂ .

  The value of the generated hydrogen was equivalent to 59.3% for the first hydrogen generator, 18.5% for the second hydrogen generator, and 77.8% in total as the raw material natural gas conversion rate. . Moreover, the sum total of the 1st hydrogen generator of the cold gas efficiency defined by the said (9) formula and the 2nd hydrogen generator was 75.2%. Thus, the fuel cell system D is operated, and the power generation efficiency of the fuel cell system D is measured. The results are shown in Table 2.

  As shown in the results of Example 1 in Table 1, the energy input to the fuel cell system A was raw material natural gas + auxiliary fuel natural gas, and the amount of heat was 3.627 kW. The power generation end output (direct current) from the PEFC fuel cell stack of fuel cell system A was 1.223 kW, and the inverter (direct current to alternating current converter) loss was 0.122 kW. Further, the power consumption of the accessory equipment such as an air blower constituting the fuel cell system A was 0.093 kW, and the recovery power (gas turbine) was 0.102 kW. With the above balance, 1.109 kW was obtained as the power transmission end output (AC) of the fuel cell system A, and the power transmission end efficiency of the fuel cell system A was 30.6%. The hot water (65 ° C.) produced by cooling the PEFC fuel cell stack, the hydrogen-containing fluid and the residual gas is 32.28 kg / h, and this value corresponds to 1.572 kW in terms of calorie, It was 43.3%. Therefore, 73.9% was obtained as the value of the overall thermal efficiency (power transmission end efficiency + warm water production rate).

  As shown in the results of Example 2 in Table 1, the energy input to the fuel cell system B was raw material natural gas, and the amount of heat was 3.100 kW. The power generation end output (direct current) from the PEFC fuel cell stack of fuel cell system B was 1.223 kW, and the inverter (direct current to alternating current converter) loss was 0.122 kW. Further, the power consumption of the accessory equipment such as an air blower constituting the fuel cell system B was 0.026 kW, and the recovery power (gas turbine and steam turbine) was 0.079 kW. With the above balance, 1.153 kW was obtained as the power transmission end output (AC) of the fuel cell system B, and the power transmission end efficiency of the fuel cell system B was 37.2%. The hot water (65 ° C.) produced by cooling the PEFC fuel cell stack, the hydrogen-containing fluid and the residual gas is 20.38 kg / h, and this value is equivalent to 0.991 kW in terms of calorie, as the hot water production efficiency It was 32.0%. Therefore, 69.2% was obtained as a value of total thermal efficiency (power transmission end efficiency + warm water production rate).

  As shown in the results of Example 3 in Table 2, the energy input to the fuel cell system C was raw material natural gas, and the amount of heat was 3.117 kW. The power generation end output (direct current) from the PEFC fuel cell stack of fuel cell system C was 1.223 kW, and the inverter (direct current to alternating current converter) loss was 0.122 kW. Further, the power consumption of the accessory devices such as an air blower and IDF constituting the fuel cell system C was 0.142 kW, and the recovery power (gas turbine and steam turbine) was 0.138 kW. With the above balance, 1.097 kW was obtained as the power transmission end output (AC) of the fuel cell system C, and the power transmission end efficiency of the fuel cell system C was 35.2%. The hot water (65 ° C.) produced by cooling the PEFC fuel cell stack, hydrogen and residual gas is 17.47 kg / h, this value corresponds to 0.855 kW in terms of calorie, and the hot water production efficiency is 27. 4%. Therefore, 62.6% was obtained as a value of total thermal efficiency (power transmission end efficiency + warm water production rate).

  As shown in the results of Example 4 in Table 2, the energy input to the fuel cell system D was raw material natural gas, and the amount of heat was 3.031 kW. The power generation end output (direct current) from the PEFC fuel cell stack of fuel cell system D was 1.223 kW, and the inverter (direct current to alternating current converter) loss was 0.122 kW. In addition, the power consumption of accessory devices such as an air blower and IDF constituting the fuel cell system D was 0.092 kW, and the recovery power (gas turbine and steam turbine) was 0.077 kW. With the above balance, 1.085 kW was obtained as the power transmission end output (AC) of the fuel cell system D, and the power transmission end efficiency of the fuel cell system D was 35.8%. The hot water (65 ° C.) produced by cooling the PEFC fuel cell stack, hydrogen and residual gas is 16.67 kg / h, this value corresponds to 0.821 kW in terms of calorie, and the hot water production efficiency is 27. 1%. Therefore, 62.9% was obtained as a value of the total thermal efficiency (power transmission end efficiency + warm water production rate).

  As described above, in all of Examples 1 to 4, the power transmission end efficiency exceeds 30%, and it can be said that the fuel cell systems A to D are systems with high energy efficiency. In addition, since the power transmission end efficiency of Example 2 is higher than that of Example 1 and the power transmission end efficiency of Example 4 is higher than that of Example 3, the air sent to the catalytic reaction chamber is converted to pure oxygen. It has been found that the energy efficiency of the fuel cell system can be improved by changing. Furthermore, since Example 3 has lower 65 ° C. warm water production efficiency than Example 1 and Example 4 has lower 65 ° C. hot water production efficiency than Example 2, the permeate hydrogen receiving chamber is decompressed by the decompression unit. As a result, it was found that the energy used for hot water production can be reduced. That is, it has been found that the optimum system of Examples 1 to 4 can be applied according to the energy demand pattern of the fuel cell system (power transmission end efficiency or hot water production efficiency).

1 is a schematic diagram showing a fuel cell system according to a first embodiment of the present invention. It is sectional drawing which shows an example of the hydrogen generator used for the fuel cell system of this invention. It is a schematic diagram which shows the fuel cell system concerning 2nd embodiment of this invention. It is a schematic diagram which shows the fuel cell system concerning 3rd embodiment of this invention. It is a schematic diagram which shows the fuel cell system concerning 4th embodiment of this invention.

Explanation of symbols

10, 500, 600, 700 Fuel cell system 16, 23, 115, 118, 128, 130, 132, 154, 158, 166, 172, 192, 210, 212, 220, 230, 232, 234, 250, 252, 610, 640 Piping 20 Composite preheater 22 Air heating unit 24 Steam heating unit 26 Raw material heating unit 80 Catalytic combustion device 100, 620 First hydrogen generator 112 Hydrogen permeable membrane 114, 124, 624, 634 Permeated hydrogen receiving chamber 116, 126, 626, 636 Catalytic reaction chamber 120, 630 Second hydrogen generator 134 Gas turbine 150 Steam generator 155, 160 Heat exchanger 170, 190 Gas-liquid separator 300 Fuel cell 642 Decompression unit

Claims (4)

A fuel cell;
A steam generator,
A catalytic combustion apparatus that is filled with an oxidation catalyst and burns in contact with a combustible gas to the oxidation catalyst;
A plurality of hydrogen generators provided with a catalytic reaction chamber and a permeated hydrogen receiving chamber partitioned by a hydrogen permeable membrane, the catalyst reaction chamber being filled with a hydrocarbon reforming catalyst;
A raw material preheating device that heats light hydrocarbons using the combustion heat generated in the catalytic combustion device as a heat medium ;
Means for supplying light hydrocarbons heated by the raw material preheating device to any of the catalytic reaction chambers;
An oxygen preheating device that heats a fluid containing oxygen using combustion heat generated in the catalytic combustion device as a heat medium ;
Means for supplying a fluid containing oxygen heated by the oxygen preheating device to any of the catalytic reaction chambers;
A steam preheating device that heats the steam generated in the steam generator using the combustion heat generated in the catalytic combustion device as a heat medium ;
Means for supplying steam heated by the steam preheating device to any of the catalytic reaction chamber and the permeated hydrogen receiving chamber ;
Hydrogen supply means for supplying hydrogen generated by the hydrogen generator to the fuel cell;
Hydrogen generated from light hydrocarbons in the catalytic reaction chamber of any of the hydrogen generators permeates through the permeated hydrogen receiving chamber partitioned by the hydrogen permeable membrane, and separates from residual gas remaining in the catalytic reaction chamber; Supplying the residual gas to the catalytic reaction chamber of another hydrogen generator;
The water vapor generating device includes a residual gas remaining in a catalytic reaction chamber of a hydrogen generating device located most downstream in the hydrogen generating device, a permeated hydrogen reception of a hydrogen generating device located most downstream in the hydrogen generating device. Generating steam by using hydrogen permeated into the chamber and combustion heat generated in the catalytic combustion device used as a heat medium in the raw material preheating device, the oxygen preheating device and the steam preheating device as a heat medium. A fuel cell system is characterized. 2. The fuel cell system according to claim 1 , wherein the hydrogen supply unit includes a decompression unit that decompresses the permeated hydrogen receiving chamber. 3. The fuel cell system according to claim 1, further comprising means for supplying residual gas used as a heat medium in the water vapor generating apparatus to the catalytic combustion apparatus. 4. The fuel cell system according to any one of claims 1 to 3 , wherein the permeated hydrogen receiving chamber is filled with inert particles.

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