JP2008037691A - Carbon monoxide reduction apparatus, carbon monoxide reduction method, hydrogen production apparatus, and fuel cell power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve such a problem that, concerning CO reduction by CO selective oxidation of a reformed gas obtained by subjecting an oxygen-containing hydrocarbon to reformation reaction, an unreacted and undecomposed material and a by-product in the reformed gas badly influence on a CO-selective oxidation reaction. <P>SOLUTION: A raw material supplied from a raw material supply section 1 is reformed by a reformer 3 to give a reformed gas; the concentrations of an unreacted and undecomposed raw material and of a by-product are detected by an impurity concentration detector 4; and when the impurity concentration is higher than a preset value, the reformed gas is introduced into an impurity decreasing receptacle 5 to decrease the impurity concentration in the reformed gas and then is introduced into a CO selective oxidation reactor 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a carbon monoxide reduction device, a carbon monoxide reduction method, a hydrogen production device, and a fuel cell power generation system.

  One of the new energies is hydrogen, and its production method is generally known to be a reforming reaction of fossil fuels mainly composed of hydrocarbons, or electrolysis of water or steam.

In recent years, attention has been focused on fuel cells that convert chemical energy into electrical energy by electrochemically reacting hydrogen and oxygen as an application field of hydrogen. Fuel cells have high energy use efficiency and are being developed as large-scale distributed power sources, household power sources, and mobile power sources. Fuel cells are classified into a solid polymer type, a phosphoric acid type, a molten carbonate type, a solid oxide type, etc. according to the temperature range and the type of material and fuel used. These are mainly used for power generation by reforming hydrocarbon fuels such as methanol, methane, propane, gasoline, and kerosene using a steam reforming reaction or partial oxidation reaction to extract H ₂ .

When these hydrocarbon fuels are reformed, the reformed gas contains substances other than hydrogen, such as carbon dioxide (CO ₂ ), carbon monoxide (CO), and lower hydrocarbons. The CO contained in the reformed gas becomes a poisoned component when the Pt-based catalyst is used at the fuel electrode and operates at a relatively appropriate temperature such as the above-described polymer electrolyte fuel cell, and reduces the power generation performance. Therefore, it is necessary to reduce CO in the reformed gas to an extremely low concentration. In general, methods for reducing CO include shift reaction, catalytic combustion reaction, adsorption method and the like. In particular, in a catalytic combustion reaction, a CO selective oxidation reaction that selectively oxidizes CO to reduce the concentration is used (see, for example, Patent Document 1).

In addition, when reformed gas containing unreacted fuel is supplied to the fuel cell, there is a concern that it may adhere to the electrode and reduce the power generation performance and life. In this case, removal of impurities such as hydrocarbons is an issue, and removal is performed by performing selective oxidation on unreacted fuel in the reformed gas (see, for example, Patent Document 2).
Japanese Patent Laid-Open No. 9-30802 JP-A-9-106826

In the above-described conventional technology, the adverse effect of the unreacted raw material in the reformer and the undecomposed fuel and by-products not decomposed to H ₂ on the CO selective oxidation reaction is not particularly considered. Carbon monoxide reduction devices are not focused on these problems.

  Accordingly, an object of the present invention is to provide an apparatus and a method that improve the reduction performance of CO in the reformed gas by reducing impurities in the reformed gas.

In order to achieve the above object, a carbon monoxide reduction apparatus according to the present invention includes a raw material supply unit that supplies an oxygen-containing hydrocarbon as a raw material, the raw material as a reformed gas by a reforming reaction, and the reformed gas is discharged. A reformer, an undecomposed raw material that has not been decomposed to H ₂ by the reformer in the reformed gas in which the oxygen-containing hydrocarbon is reformed by the reformer, and the reformer. Impurity reducer for reducing the concentration of at least one of impurities formed of unreacted raw materials and by-products, CO selective oxidation reactor for reducing CO in the reformed gas, and CO selective oxidation reactor An impurity concentration detector that detects the concentration of at least one of the impurities in the reformed gas, and a path from the reformer to the CO selective oxidation reactor. To control And a control unit that controls the operation and stop of the impurity reducer and the opening and closing of the valve based on the concentration detected by the impurity concentration detector.

In the carbon monoxide reduction method according to the present invention, an oxygen-containing hydrocarbon as a raw material is supplied from a raw material supply unit, the oxygen-containing hydrocarbon is used as a reformed gas by a reformer, and CO in the reformed gas is converted into CO. A method for reducing carbon monoxide that is reduced by a CO selective oxidation reactor, wherein the impurities comprise unreacted raw materials, undecomposed raw materials and by-products in the reformed gas before the CO selective oxidation reactor. The hydrogen production apparatus according to the present invention is characterized in that at least one of the concentrations is detected, and impurities are reduced when the detected concentration is higher than a set concentration. A hydrogen storage medium for storing the reformed gas with reduced CO is provided.

  The fuel cell power generation system according to the present invention includes a fuel cell that generates electric power using the reformed gas and oxygen in which CO is reduced by the carbon monoxide reduction device.

  According to the present invention, carbon monoxide in the reformed gas can be reduced, and high purity hydrogen can be produced. Further, the operation cost can be reduced by minimizing the operation of the impurity reducer.

  Embodiments of a carbon monoxide reduction device, a carbon monoxide reduction method, a hydrogen production device, and a fuel cell power generation system according to the present invention will be described below with reference to FIGS.

  FIG. 1 shows the CO selective oxidation reaction characteristic in the CO selective oxidation reaction.

The horizontal axis represents O ₂ / CO (molar ratio), and the vertical axis represents the CO ₂ concentration. The gas conditions are dry-base, CO: 5000 ppm, CO ₂ : 25 vol%, dimethyl ether (DME): 20 vol%, H ₂ balance gas, and dry-base, CO: 5000 ppm, CO ₂ : 25 vol%, H ₂ balance. There are two conditions in which 25 vol% of water vapor is added to each of these gases. The catalyst is Pt, the catalyst temperature is 150 ° C., and the space velocity is SV = 15000 h ⁻¹ . Comparing the data, it can be seen that the CO concentration is further reduced in the gas not containing dimethyl ether shown by the black dot plot in FIG.

FIG. 2 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. 1 the raw material supply unit for supplying a raw material, 2 supplies of H _{2 O} in the raw material supplied from the raw material supply unit, H _{2 O} supply unit to mix, 3 reforming the raw material supplied from the raw material supply unit 1 Impurity concentration detection that detects the concentration of at least one of the impurities composed of unreacted and undecomposed raw materials and by-products contained in the reformed gas. 5 is an impurity reducer for reducing the concentration of impurities in the reformed gas, 6 is an oxidant supply unit for supplying an oxidant to the reformed gas, and 7 is a CO filled with CO in the reformed gas. CO selective oxidation reactors 8a, 8b, 8c, and 8d that reduce CO in the reformed gas by oxidizing with a selective oxidation reaction catalyst are introduced into the CO selective oxidation reactor 7 from the reformer 3 Valve installed to control the path through which it is done, 9 is impure The control unit controls the operation and stop of the impurity reducer 5 and the opening and closing of the valves 8a, 8b, 8c, and 8d by comparing the impurity concentration in the reformed gas obtained from the substance concentration detector 4 with the set concentration. A broken line indicates that the control unit 9, the impurity concentration detector 4, the impurity reducer 5, and the control unit 9 are connected so as to be communicable by wire or wirelessly. Although not shown, the valves 8a, 8b, 8c, 8d and the control unit are also connected by wire or wirelessly.

The raw material supplied from the raw material supply unit 1 targets oxygen-containing hydrocarbons, and examples thereof include methanol, ethanol, propanol, and dimethyl ether. Water vapor is supplied from the H ₂ O supply unit 2. The reformer 3 is filled with a reforming catalyst or a partial oxidation catalyst. The impurity concentration detector 4 detects the concentration of impurities such as unreacted and undecomposed raw materials and by-products contained in the reformed gas, but one or more types of impurities may be detected. The impurity reducer 5 reduces unreacted and undecomposed raw materials and by-products contained in the reformed gas. Examples of the oxidizing agent supplied from the oxidizing agent supply unit 6 include a gas containing O ₂ . The CO selective oxidation reaction catalyst charged in the CO selective oxidation reactor 7 mainly contains a noble metal as an active component. As for the type of the CO selective oxidation reaction catalyst, a metal having a low CH ₄ production reaction activity, such as Pt, Au, Pd, or the like is desirable as an active component. Although these may be single, mixed, or alloyed, it is particularly desirable to contain Pt. As the shape of the catalyst, a spherical shape, a cylindrical shape, a pellet, and the like are conceivable. A honeycomb type catalyst or a foam-supported type catalyst may be used.

Raw material supplied from the raw material supply unit 1 by mixing and entrainment of H _{2 O} supplied from the H _{2 O} supply unit 2 is introduced into the reformer 3, the reformed gas is generated. For the reformed gas, the control unit 9 compares the impurity concentration detected by the impurity concentration detector 4 with the set concentration, and based on the result, the control unit opens and closes the valves 8a, 8b, 8c and 8d and reduces the impurities. The operation and stop of the device 5 are controlled. For example, if the impurity concentration processing is set to perform impurity reduction processing when the detected impurity concentration is higher than the set concentration, the control unit 9 closes the valves 8a and 8b when the impurity concentration detector 4 detects a concentration higher than the set concentration. The valves 8c and 8d are opened and the impurity reducer 5 is operated. As a result, the reformed gas is introduced into the impurity reducer 5 and is sent to the CO selective oxidation reactor 7 after the impurities are reduced. When the impurity concentration detector 4 detects a concentration equal to or lower than the set concentration, the control unit 9 opens the valves 8a and 8b, closes the valves 8c and 8d, stops the impurity reducer 5, and the reformed gas is directly subjected to CO selective oxidation. Sent to the reactor 7. The operation of such a series of control units is shown in the flowchart of FIG. In FIG. 3, the concentration detected by the impurity concentration detector 4 is indicated by x, and the set concentration is indicated by a.

The reformed gas is mixed and entrained with the oxidant supplied from the oxidant supply unit 6 and introduced into the CO selective oxidation reactor 7. After the CO is reduced, for example, a fuel cell, an H ₂ storage medium, etc. It is sent to a subsequent process (not shown).

Although the reformer 3 has been described as performing steam reforming, a partial oxidation reaction may be used as the reforming reaction. In that case, water vapor or gas containing oxygen is supplied instead of H ₂ O.

Further, as shown in FIG. 4, the valves 8a, 8b, 8c, and 8d may be substituted by using three-way valves 10a and 10b. Further, when the operating temperature of the reformer 3 is high, the equilibrium concentration of CO production becomes high. In this case, a shift reactor 11 may be provided between the reformer 3 and the CO selective oxidation reactor 7 as shown in FIG. In the shift reactor 11, CO and water vapor in the reformed gas cause a shift reaction (CO + H ₂ O → CO ₂ + H ₂ ), and CO in the reformed gas is reduced.

  According to this embodiment, carbon monoxide in the reformed gas can be reduced, and high purity hydrogen can be produced. Further, the operation cost can be suppressed by minimizing the operation of the impurity reducer 5. Further, maintenance of the impurity reducer 5 can be performed without stopping the system.

  FIG. 5 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the structure same as Example 1, and the overlapping description is abbreviate | omitted. In this embodiment, a plurality of impurity reducers 5a and 5b are installed in series.

  The configuration of the impurity reducers used for the impurity reducers 5a and 5b may be the same or different. However, different components can be reduced in the impurity reducers 5a and 5b by using different configurations.

  According to the present embodiment, for example, by using a plurality of impurity reducers having different configurations, a plurality of types of impurities can be targeted for reduction, and impurities can be more efficiently generated than when a single impurity reducer is installed. Can be reduced.

  FIG. 6 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the structure same as Example 1, and the overlapping description is abbreviate | omitted. In this embodiment, a plurality of impurity reducers 5a and 5b are installed in parallel. When the impurity reducer 5 is arranged in parallel, there is no need for a path for introducing the reformed gas from the impurity concentration detector 4 to the CO selective oxidation reactor 7 without going through the impurity reducer 5. As shown in FIG. 6, it is desirable to keep these paths in parallel. The operation and stop control of the impurity reducers 5a and 5b can be performed individually. Further, valves 8e, 8f, 8g, and 8h are installed immediately before and after each of the impurity reducers 5a and 5b.

  In this embodiment, the concentration for operating both impurity reducers and the concentration for stopping the impurity reducers can be set, and only one impurity reducer can be set to operate in the middle range. In the present embodiment, when three or more impurity reducers are installed, it is desirable to set a more detailed concentration range according to the total number of impurity reducers to be operated. Further, the selection of the impurity reducer to be operated can be set separately. For example, it is possible to switch the operation alternately at regular intervals, or to determine based on the concentration detected by the impurity concentration detector 4 when there is a performance difference between the impurity reducers 5a and 5b.

  Moreover, when installing three or more impurity reducers, you may install an impurity reducer combining the parallel and the series.

  According to the present embodiment, the impurity reducer can be efficiently operated according to the impurity concentration in the reformed gas, and the operating cost can be suppressed by operating the impurity reducer only to the minimum necessary level. . Moreover, it is possible to perform maintenance of the impurity reducer without stopping all the impurity reducers.

  FIG. 7 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the structure same as either of Example 1 thru | or Example 3, and the overlapping description is abbreviate | omitted. In this embodiment, a plurality of impurity concentration detectors 4a and 4b are installed. The impurity concentration detector 4a is installed at the subsequent stage of the reformer 3, and the impurity concentration detector 4b is installed immediately before the oxidizing agent is supplied from the oxidizing agent supply unit 6. The impurity components detected by the impurity concentration detectors 4a and 4b may be the same or different.

  From the detection result of the impurity concentration detector 4a, when the reformed gas is introduced into the impurity reducer, the impurity concentration in the gas is detected by the impurity concentration detector 4b for the reformed gas with reduced impurities, If the resulting impurity concentration is equal to or higher than the set value, the performance of the impurity reducer 5 (5a, 5b) is improved. That is, for example, when a plurality of impurity reducers 5a and 5b are installed in parallel as shown in FIG. 3, the number of operations is increased when some of the impurity reducers are operated. In the present embodiment, the impurity concentration detector 4a is not necessarily required, but compared with the case where the impurity concentration detector 4a is installed, a reformed gas having impurities of a set concentration or more is introduced into the CO selective oxidation reactor 7. You should consider the event of increased likelihood.

  According to the present embodiment, the reforming introduced into the CO selective oxidation reactor 7 is detected by detecting the impurity concentration in the reformed gas introduced into the CO selective oxidation reactor 7 and controlling the impurity reducer 5. The impurity concentration in the gas can be kept lower than the set value.

  FIG. 8 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the structure same as any of Example 1 thru | or Example 4, and the overlapping description is abbreviate | omitted. In this embodiment, a CO concentration detector 12 for detecting the CO concentration in the reformed gas is installed at the subsequent stage of the CO selective oxidation reactor 7, and the oxidant supply unit 6 is communicably connected to the control unit. . When CO of the set concentration or more is detected by the CO concentration detector 12, for example, the performance of the impurity reducer 5 (5a, 5b) is improved in accordance with the method of the fourth embodiment described above.

Further, FIG. 1 shows that the CO selective oxidation reaction is dependent on O ₂ / CO (molar ratio). From this, it is possible to adjust the mixing / entrainment amount of the supplied oxidant by controlling the oxidant supply unit 6 based on the CO concentration obtained from the CO concentration detector 12, thereby suppressing the CO concentration. Is possible.

  According to this embodiment, the CO concentration of the reformed gas discharged from the CO selective oxidation reactor 7 is detected, and the impurity reducer 5 and the oxidant supply unit 6 are controlled based on the detected concentration, so that it is sent to the subsequent process. The CO concentration in the reformed gas can be kept lower than the set value.

FIG. 8 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the structure same as either of Example 1 thru | or Example 5, and the overlapping description is abbreviate | omitted. In this embodiment, a CH ₄ detector 13 for detecting CH ₄ in the reformed gas is installed after the CO selective oxidation reactor 7, and the oxidant supply unit 6 is communicably connected to the control unit 9. Yes. If the CH ₄ is detected in the CH ₄ detector 13, improves the performance of the impurity reducer 5 according to the method of Example 4 described above.

FIG. 9 shows the CH ₄ production characteristics by the CO selective oxidation reaction in the CO selective oxidation reactor 7. The horizontal axis represents O ₂ / CO (molar ratio), and the vertical axis represents the CH ₄ concentration. The gas conditions are dry-base, CO: 5000 ppm, CO ₂ : 25 vol%, dimethyl ether 20: vol%, H ₂ balance gas, and dry-base, CO: 5000 ppm, CO ₂ : 25 vol%, H ₂ balance gas. There are two conditions in which 25 vol% of water vapor is added to each. The catalyst is Pt, the catalyst temperature is 150 ° C., and the space velocity is SV = 15000 h ⁻¹ . In the gas containing dimethyl ether, CH ₄ was generated with O ₂ / CO = 3 or more. FIG. 9 shows that CH ₄ production in the CO selective oxidation reaction of a gas containing dimethyl ether is dependent on O ₂ / CO (molar ratio). From this, it is possible to adjust the mixing / entrainment amount of the oxidant supplied by controlling the oxidant supply unit 6 as necessary based on the CH ₄ detection result obtained from the CH ₄ detector 13. ₄ generation can be suppressed.

Further, both the CO concentration detector 12 and the CH ₄ detector 13 described in the fifth embodiment may be installed. The order of installation of the CO concentration detector 12 and the CH ₄ detector 13 is not particularly limited.

According to this embodiment, the generation of CH ₄ that is not used for the power generation reaction but is only used as a combustion fuel for the heat source necessary for the reforming reaction is suppressed, and H ₂ is wasted in the generation of CH _4. Can be prevented.

  FIG. 10 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 6, and the overlapping description is abbreviate | omitted.

In the present embodiment, the impurity reducers 5a and 5b reduce impurities in the reformed gas again using a reforming reaction or dehydrogenation reaction. Steam reforming, partial oxidation reaction, or the like is used for the reforming reaction for reducing impurities. When performing steam reforming, in addition H ₂ in the reformed gas introduced into the impurity reducer to O of the first H _{2 O} supply section 2a supplies of H _{2 O} in the raw material supplied from the material feed portion 1 A second H ₂ O supply unit 2b is provided. Without installing of H ₂ O supply unit 2b, and both of _{H 2} O supplied to the _{H 2} O supply and the reforming gas to the raw material may be performed by _{H 2} O supply section 2a. When the partial oxidation reaction is performed, the second oxidant supply unit 6b is installed.

  FIG. 11 is a side sectional view showing an outline of an example of an impurity reducer using a reforming reaction. FIG. 11A shows a catalyst-filled reactor filled with the reforming catalyst 14, and FIG. 11B shows a membrane type reformer provided with the reforming catalyst film 15. 30 is a reformed gas inlet for introducing the reformed gas, and 31 is a reformed gas outlet for discharging the reformed gas.

  The reformed gas mixed with water vapor is introduced from the reformed gas introduction port 30 and comes into contact with the reforming catalyst 14 or the reforming catalyst film 15, and impurities in the reformed gas are reformed by the reforming reaction. The gas is discharged from the gas outlet 31. Examples of the catalyst used in these reactions include catalysts having an active component of a noble metal such as Pt, Au, Pd, or Ru, or a metal or metal oxide such as Ni, Fe, Cu, Zn, or Co. Any type. A plurality of these active ingredients may be mixed, or may be used after being alloyed. The type of the active ingredient carrier is not particularly limited. The same catalyst as that used in the reformer 3 may be used, or a different catalyst may be used. The impurity reducers 5a and 5b may not have the same configuration. Further, these catalysts may be mixed and packed in the same reactor or packed in multiple layers.

  According to the present embodiment, the unreacted or undecomposed raw material in the reformed gas is reformed again, thereby increasing the hydrogen production amount per raw material unit amount and increasing the hydrogen production efficiency.

  FIG. 12 is a side cross-sectional view schematically showing an impurity reducer that reduces impurities in the reformed gas by dissolving impurities in the reformed gas in a solvent. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 7, and the overlapping description is abbreviate | omitted.

  In the present embodiment, a method for dissolving impurities in the reformed gas in a solvent includes, for example, a gas-liquid contact absorption method. FIG. 12 (a) shows a bubbling method in which a reformed gas is bubbled with respect to a solvent, FIG. 12 (b) shows a gas absorption tower using a filler, and FIG. 12 (c) shows a multistage bed inside. It is a sectional side view which shows the outline of a multistage bed type gas absorption tower. Examples of the solvent used for the impurity reducer 5 include water, organic solvents, acids, and alkalis. For example, when dimethyl ether is used as a raw material, dimethyl ether remains in the reformed gas as an unreacted component. When water is used as the solvent, 7 g of dimethyl ether is dissolved in 100 g of water having a water temperature of 18 ° C.

  In FIG. 12A, 17 is a solvent, 32 is a solvent inlet for introducing the solvent 17 into the impurity reducer 5, and 33 is a solvent outlet for discharging the solvent 17 in which impurities are dissolved. The reformed gas introduced from the reformed gas inlet 30 passes through the solvent 17, and impurities contained in the reformed gas are absorbed by the solvent 17 during that time. Thereafter, the reformed gas is discharged from the reformed gas outlet 31.

  In FIG. 12B, reference numeral 18 denotes a filler filled in the gas absorption tower, and for example, Raschig rings are used as the filler.

  In the gas absorption tower of FIG. 12B and the multistage bed type gas absorption tower of FIG. 12C, the reformed gas is supplied from the reformed gas inlet 30 at the lower part of the gas absorption tower, and the solvent is the solvent at the upper part of the gas absorption tower. The reformed gas introduced into the gas absorption tower through the inlet 32 and rising to the reformed gas outlet 31 comes into contact with the solvent descending to the solvent outlet 33, and the impurities in the reformed gas are dissolved in the solvent. When the solvent is water, the solvent in which the impurities discharged from the solvent outlet 33 are dissolved is mixed with the raw material introduced into the reformer 3.

  Examples of a method for supplying the solvent to the impurity reducer 5 (5a, 5b) include a batch method and a continuous supply method.

  FIG. 13 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. A solvent supply unit 16 supplies the solvent to the impurity reducer 5. In addition, a pipe for supplying a solvent in which impurities discharged from the impurity reducer 5 are dissolved to the raw material introduced into the reformer 3 is provided.

  According to this example, by introducing a solvent in which impurities are dissolved by using water as the solvent into the reformer and reforming again, the hydrogen production amount per unit amount of raw material is increased, and the hydrogen production efficiency is increased. Can be increased.

  FIG. 14 is a block diagram showing the configuration of the carbon monoxide reduction apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 6, and the overlapping description is abbreviate | omitted.

  In the present embodiment, the impurity reducer 5 (5a, 5b) uses the separation membrane to separate and remove and reduce impurities in the reformed gas. FIG. 15 is a side sectional view showing an outline of the impurity reducer 5 for separating and removing impurities in the reformed gas by using a separation membrane and reducing the concentration thereof. Reference numeral 19 denotes a separation membrane, and 34 denotes an impurity discharge port for discharging impurities separated from the reformed gas by the separation membrane 19. The reformed gas is introduced from the reformed gas introduction port, hydrogen contained in the reformed gas passes through the separation membrane 19, and impurities contained in the reformed gas cannot pass through the separation membrane 19 and are discharged from the impurity discharge port 34. Is done. The discharged impurities are introduced into the reformer 3 and reformed.

  Examples of the material of the separation medium used for the separation membrane 19 include porous membranes such as ceramics and polymers. As the material of the ceramic film, alumina, silica, titania, silicon carbide, silicon nitride, or the like is desirable. A mixture of these may also be used. The polymer membrane is not particularly limited in type, but is preferably polyimide, cellulose, silicone rubber, polysulfone, or fluorinated ethylene.

  According to the present embodiment, the separated impurities are again introduced into the reformer 3 and reformed again, whereby the amount of hydrogen produced per unit amount of raw material can be increased and the hydrogen production efficiency can be increased. Moreover, the purity of the hydrogen to be produced can be increased by appropriately setting the pore diameter of the separation membrane. Moreover, when water vapor | steam is separable, the performance of a CO selective oxidation reactor will improve.

  FIG. 16 is a side sectional view schematically showing an impurity reducer provided in the carbon monoxide reducing apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 6, and the overlapping description is abbreviate | omitted.

  35 is a gas adsorption tower using a pressure swing adsorption method, and 20 is an adsorbent filled in the gas absorption tower 35. In this embodiment, the adsorption tower 35 is used to separate and remove impurities in the reformed gas, and the concentration thereof is reduced. Examples of the material of the adsorbent include activated carbon, zeolite, clay, activated alumina, silica gel, and polymer. Also, these may be loaded with other components or mixed. Moreover, as a process for separating and removing impurities other than the pressure swing adsorption method, for example, a temperature swing adsorption method and the like can be cited. When the inside of the gas adsorption tower 35 is at a high pressure, the reformed gas is introduced from the reformed gas inlet 30, and the impurities are adsorbed on the adsorbent 20 and separated from the reformed gas. The impurities are reduced from the reformed gas outlet. The reformed gas is discharged. When the pressure in the gas absorption tower 35 is low, the reformed gas is not supplied, impurities are released from the adsorbent 20, and impurities are discharged from the impurity outlet 34.

  FIG. 17 is a block diagram showing an example of the configuration of the apparatus according to this embodiment. Reference numerals 35a and 35b denote gas adsorption towers that are interlocked so that when one is performing impurity adsorption and the other is desorbing impurities, it corresponds to the impurity reducer 5. Impurities separated from the reformed gas are introduced into the reformer 3 and reformed again.

  According to the present embodiment, the separated impurities are again introduced into the reformer 3 and reformed again, whereby the amount of hydrogen produced per unit amount of raw material can be increased and the hydrogen production efficiency can be increased. Further, the purity of hydrogen to be produced can be increased by controlling the type of adsorbent and the process of the adsorption method.

  FIG. 18 is a block diagram showing the configuration of the hydrogen production apparatus according to this embodiment. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 6, and the overlapping description is abbreviate | omitted.

  Reference numeral 21 denotes a hydrogen storage medium such as a tank for storing the reformed gas whose CO is reduced by the CO selective oxidation reactor 7 or a hydrogen storage alloy.

  According to this embodiment, it is possible to store high-purity hydrogen in which CO is efficiently reduced.

  FIG. 19 is a block diagram showing the configuration of the fuel cell power generation system according to this embodiment. In addition, the same code | symbol is attached | subjected to the same structure as any one of Example 1 thru | or Example 6, and the overlapping description is abbreviate | omitted.

  Reference numeral 22 denotes an oxidizing gas supply unit for supplying an oxidizing gas to the fuel cell, 23 denotes a reformed gas mainly composed of hydrogen whose CO is reduced by the CO selective oxidation reactor 5, and an oxidizing gas supplied from the oxidizing gas supply unit 22. It is a fuel cell that generates electricity by electrochemical reaction with gas. Examples of the fuel cell include a polymer electrolyte fuel cell that operates at a relatively low temperature and uses a Pt-based catalyst for the fuel electrode. Further, if the oxidizing gas supplied from the oxidizing gas supply unit 22 can be replaced by the oxidizing agent supplied from the oxidizing agent supply unit 6, the oxidizing gas supply unit 22 is supplied by supplying the oxidizing agent from the oxidizing agent supply unit 6 to the fuel cell. It does not matter as an alternative.

  According to the present embodiment, CO in the reformed gas that is a poisoning component of the fuel cell can be efficiently reduced, and a decrease in power generation performance can be prevented.

  As mentioned above, although several Example was demonstrated about this invention, you may use combining several Example among each Example demonstrated above.

CO selective oxidation reaction characteristic graph showing the relationship between the molar concentration ratio and CO CO concentration after the selective oxidation reaction of CO prior to selective oxidation reaction O _{2 /} CO. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 1 of this invention. The flowchart which shows operation | movement of the control part of the carbon monoxide reduction apparatus by Example 1 of this invention. The block diagram which shows the modification of the carbon monoxide reduction apparatus by Example 1 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 2 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 3 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 4 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 5 and Example 6 of this invention. CH ₄ generation characteristic graph showing the CH ₄ concentration relationships molar concentration ratio of CO prior to selective oxidation reaction _O 2 / CO and CO after the selective oxidation reaction. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 7 of this invention. The sectional side view which shows the outline of the impurity reducer by Example 7 of this invention. The sectional side view which shows the outline of the impurity reducer by Example 8 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 8 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 9 of this invention. The sectional side view which shows the outline of the impurity reducer by Example 9 of this invention. Side sectional drawing which shows the outline of the impurity reducer by Example 10 of this invention. The block diagram which shows the structure of the carbon monoxide reduction apparatus by Example 10 of this invention. The block diagram which shows the structure of the hydrogen production apparatus by Example 11 of this invention. The block diagram which shows the structure of the fuel cell power generation system by Example 12 of this invention.

Explanation of symbols

1 raw material supply unit 2,2a, 2b _{H 2} O supply unit 3 reformer 4, 4a, 4b impurity concentration detector 5, 5a, 5b impurity reducer 6 oxidant supplier 7 CO selective oxidation reactor 8a, 8b, 8c, 8d, 8e, 8f, 8g, 8h, 8i, 8j Valve 9 Control unit 10a, 10b Three-way valve 11 Shift reactor 12 CO concentration detector 13 CH ₄ detector 14 Reforming catalyst 15 Reforming catalyst film 16 Solvent supply Unit 17 solvent 18 filler 19 separation membrane 20 adsorbent 21 hydrogen storage medium 22 oxidizing gas supply unit 23 fuel cell 30 reformed gas inlet 31 reformed gas outlet 32 solvent inlet 33 solvent outlet 34 impurity outlet 35, 35a, 35b Gas adsorption tower

Claims (15)

A raw material supply section for supplying oxygen-containing hydrocarbons as raw materials;
A reformer that discharges the reformed gas using the raw material as a reformed gas by a reforming reaction;
The oxygen-containing hydrocarbon is contained in the reformed gas reformed by the reformer, the undecomposed raw material not decomposed to H ₂ by the reformer and the unreacted raw material not reacted by the reformer And an impurity reducer for reducing the concentration of at least one of the impurities composed of by-products,
A CO selective oxidation reactor for reducing CO in the reformed gas;
An impurity concentration detector that is disposed upstream of the CO selective oxidation reactor and detects the concentration of at least one of the impurities in the reformed gas;
A valve for controlling a path from the reformer to the CO selective oxidation reactor;
A control unit that controls the operation and stop of the impurity reducer and the opening and closing of the valve based on the concentration detected by the impurity concentration detector;
A carbon monoxide reduction device comprising:   The carbon monoxide reduction device according to claim 1, wherein the impurity concentration detector is provided at a stage subsequent to the impurity reducer. A CO concentration detector for detecting the concentration of CO in the reformed gas after the CO selective oxidation reactor;
3. The control unit according to claim 1, wherein the control unit controls operation and stop of the impurity reducer and opening / closing of the valve based on a CO concentration detected by the CO concentration detector. 4. Carbon monoxide reduction device. A CH ₄ detector that detects the concentration of CH ₄ in the reformed gas after the CO selective oxidation reaction;
4. The control unit according to claim 1, wherein the controller controls the operation and stop of the impurity reducer and the opening and closing of the valve based on the concentration of CH ₄ detected by the CH ₄ detector. The carbon monoxide reduction device according to claim 1.   5. The carbon monoxide reduction device according to claim 1, wherein the impurity reducer reduces the concentration of impurities in the reformed gas by a steam reforming reaction.   5. The carbon monoxide reduction device according to claim 1, wherein the impurity reducer reduces the concentration of impurities in the reformed gas by a partial oxidation reaction.   5. The carbon monoxide reduction according to claim 1, wherein the impurity reducer reduces the concentration of impurities in the reformed gas by dissolving the impurities in a solvent. apparatus.   The carbon monoxide reducing device according to claim 7, wherein the solvent is water.   5. The impurity reducer includes a separation membrane, and the separation membrane separates impurities in the reformed gas to reduce the concentration of impurities in the reformed gas. The carbon monoxide reduction device according to any one of the above.   The said impurity reducer isolate | separates the impurity in the said reformed gas with adsorption agent, The density | concentration of the impurity in the said reformed gas is reduced, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Carbon monoxide reduction device.   The carbon monoxide reduction device according to any one of claims 5 to 11, wherein a component separated from the reformed gas by the impurity reducer is introduced into the reformer.   The carbon monoxide reduction device according to any one of claims 1 to 11, wherein the oxygen-containing hydrocarbon is dimethyl ether. Supply oxygen-containing hydrocarbons as raw materials from the raw material supply section,
The oxygen-containing hydrocarbon is reformed by a reformer,
A carbon monoxide reduction method for reducing CO in the reformed gas by a CO selective oxidation reactor,
In the previous stage of the CO selective oxidation reactor, the concentration of at least one component of the unreacted raw material and the undecomposed raw material and by-product impurities in the reformed gas is detected, and the detected concentration is A carbon monoxide reduction method comprising reducing the concentration of the impurity when the concentration is higher than a set concentration. A raw material supply section for supplying oxygen-containing hydrocarbons as raw materials;
A reformer that discharges the reformed gas using the raw material as a reformed gas by a reforming reaction;
The oxygen-containing hydrocarbon is contained in the reformed gas reformed by the reformer, the undecomposed raw material not decomposed to H ₂ by the reformer and the unreacted raw material not reacted by the reformer And an impurity reducer for reducing the concentration of at least one of the impurities composed of by-products,
A CO selective oxidation reactor for reducing CO in the reformed gas;
An impurity concentration detector that is disposed upstream of the CO selective oxidation reactor and detects the concentration of at least one of the impurities in the reformed gas;
A valve for controlling a path from the reformer to the CO selective oxidation reactor;
A control unit that controls the operation and stop of the impurity reducer and the opening and closing of the valve based on the concentration detected by the impurity concentration detector;
A hydrogen storage medium for storing the reformed gas in which CO is reduced by the CO selective oxidation reactor;
A hydrogen production apparatus comprising: A raw material supply section for supplying oxygen-containing hydrocarbons as raw materials;
A reformer that discharges the reformed gas using the raw material as a reformed gas by a reforming reaction;
The oxygen-containing hydrocarbon is contained in the reformed gas reformed by the reformer, the undecomposed raw material not decomposed to H ₂ by the reformer and the unreacted raw material not reacted by the reformer And an impurity reducer for reducing the concentration of at least one of the impurities composed of by-products,
A CO selective oxidation reactor for reducing CO in the reformed gas;
An impurity concentration detector that is disposed upstream of the CO selective oxidation reactor and detects the concentration of at least one of the impurities in the reformed gas;
A valve for controlling a path from the reformer to the CO selective oxidation reactor;
A control unit that controls the operation and stop of the impurity reducer and the opening and closing of the valve based on the concentration detected by the impurity concentration detector;
A fuel cell power generation system comprising: a fuel cell that generates electricity by performing an electrochemical reaction between the reformed gas with reduced CO supplied from the CO selective oxidation reactor and oxygen.

Images