JP2014046250A - Method and apparatus for removing hydrogen odorant, operation method of fuel cell and fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for removing a hydrogen odorant, enabling cyclohexene in hydrogen to be efficiently adsorbed and removed using an inexpensive active carbon, and also enabling the cyclohexene to be efficiently desorbed from a cyclohexene-absorbed active carbon, and to provide an operation method of fuel cells and system thereof using the method and apparatus.SOLUTION: The method and apparatus for removing a hydrogen odorant is provided for adsorbing cyclohexene in an active carbon and removing it by bringing a cyclohexene-containing hydrogen gas into contact with the active carbon. In the method and apparatus for removing the hydrogen odorant, an average pore size of the active carbon is 0.70-2.0 nm. Preferably, the adsorption treatment of the cyclohexene is performed at 60°C or less, the desorption treatment of the cyclohexene is performed at 70-90°C.

Description

  The present invention relates to a method and apparatus for removing a hydrogen odorant, and more particularly, to a method and apparatus for removing cyclohexene from a cyclohexene-containing hydrogen gas using activated carbon. The present invention also relates to a fuel cell operating method and a fuel cell system using this method and apparatus.

  In a fuel cell system in which gas leakage is detected by adding an odorant to the fuel gas supplied to the fuel cell, the fuel cell output characteristics will gradually deteriorate due to the odorant if the operation is continued. There is. Patent Documents 1 to 3 describe that the odorant is removed from the fuel gas and supplied to the fuel cell. Specifically, Patent Document 1 describes a method of removing a odorant by passing a fuel gas containing mercaptans and cyclohexene through a transition metal oxide, activated carbon, and a zeolite carrying silver or the like. Has been.

  Patent Document 2 describes that the odorant is adsorbed and removed with activated carbon or zeolite, and Patent Document 3 separates and removes the odorant by condensing or sublimating it by cooling the fuel gas. Is described.

  In Patent Document 4, an odorant-containing gas is supplied to a fuel cell to generate power, and when the odorant has accumulated in the fuel cell, the temperature of the fuel cell is raised to remove the odorant from the fuel cell. It is described to do.

JP2010-37480 JP 2005-327650 A JP2008-257933 JP2008-41554

  In Patent Document 1, activated carbon is used for removing mercaptans together with transition metal oxides, and cyclohexene is adsorbed and removed by zeolite carrying silver or the like.

  This zeolite carrying silver or the like is more expensive than activated carbon.

  The present invention provides a method and apparatus for removing a hydrogen odorant capable of efficiently adsorbing and removing cyclohexene in hydrogen using inexpensive activated carbon and efficiently desorbing cyclohexene from cyclohexene adsorbed activated carbon. 1 purpose.

  In Patent Documents 2 and 3, it is necessary to remove the odorant from the entire amount of the fuel gas supplied to the fuel cell, the odorant removal device such as the adsorption device becomes larger, the fuel cell power generation system becomes larger, The cost will be high. Furthermore, the running cost of power generation increases. In Patent Document 4, a temperature raising means for raising the temperature of the fuel cell when the odorant has accumulated in the fuel cell is required, and a safety device for raising the temperature of the fuel cell is required. Thus, the fuel cell power generation system becomes larger and the cost becomes higher. Furthermore, since the temperature of the fuel cell is raised to a high temperature, a steady power generation operation cannot be performed during this time, and the power generation efficiency decreases.

  The present invention solves the above problems, removes the influence of an odorant on the fuel cell by simple means, and can stably operate the fuel cell at low cost and continuously. A second object is to provide an operating method and a fuel cell system.

  The method for removing a hydrogen odorant according to the present invention is a method for removing a hydrogen odorant in which a cyclohexene-containing hydrogen gas is brought into contact with activated carbon to adsorb and remove cyclohexene on the activated carbon, and the activated carbon has an average pore diameter of 0.70. It is characterized by being -2.0 nm.

  The hydrogen odorant removing apparatus of the present invention is a hydrogen odorant removing apparatus that removes cyclohexene by adsorbing cyclohexene on activated carbon by bringing cyclohexene-containing hydrogen gas into contact with activated carbon, and the average pore diameter of the activated carbon is 0.70. It is characterized by being -2.0 nm.

  In the present invention, it is preferable to perform the cyclohexene adsorption treatment at 60 ° C. or less and the cyclohexene desorption treatment at 70 to 90 ° C.

The fuel cell operation method of the present invention is a fuel cell operation method comprising a step of supplying a cyclohexene-containing hydrogen gas to the fuel cell to generate power, and intermittently supplying the cyclohexene-free hydrogen gas to the fuel cell. The step of recovering the output voltage is characterized in that hydrogen gas that has been subjected to cyclohexene removal treatment by the method for removing a hydrogen odorant of the present invention is used as the hydrogen gas not containing cyclohexene. .
The fuel cell system of the present invention is a fuel cell system that generates power by supplying cyclohexene-containing hydrogen gas to a fuel cell, and intermittently removes the hydrogen odorant removal device of the present invention and the hydrogen gas that has been subjected to cyclohexene removal treatment by the device. And means for supplying the fuel cell to recovering the output voltage.

  In this fuel cell operating method and fuel cell system, the cyclohexene-free hydrogen gas may be supplied to the fuel cell when the output voltage of the fuel cell falls below a predetermined value.

  In this fuel cell operating method and fuel cell system, the warm drainage of the fuel cell may be used as a heating heat source when the activated carbon adsorbing cyclohexene is heated to desorb cyclohexene.

  In the method and apparatus for removing a hydrogen odorant according to the present invention, by using activated carbon having an average pore diameter of 0.70 to 2.0 nm, cyclohexene in a cyclohexene-containing hydrogen gas can be efficiently adsorbed and removed by activated carbon. .

  From the activated carbon which adsorb | sucked this cyclohexene, cyclohexene can fully be desorbed at a comparatively low temperature of 70-90 degreeC. Accordingly, it becomes possible to use, for example, the warm drainage of the fuel cell as the heat source for desorption, and the heat source for desorption becomes inexpensive. Moreover, it becomes possible to use a simple thing as a desorption temperature rising mechanism.

  In the fuel cell operation method and fuel cell system of the present invention, cyclohexene-containing hydrogen gas is supplied to the fuel cell to generate power, and fuel is generated intermittently, for example, when the power generation output of the fuel cell decreases due to the influence of cyclohexene. A hydrogen gas not containing cyclohexene is supplied to the battery. Thus, by supplying cyclohexene-free hydrogen gas to the fuel cell, cyclohexene adhering to the fuel cell is removed, and the power generation output of the fuel cell is recovered. In the present invention, since the hydrogen gas produced by the method for removing a hydrogen odorant of the present invention is used as the hydrogen gas not containing cyclohexene, the hydrogen gas cost is low. In the present invention, a configuration for removing the odorant by raising the temperature of the fuel cell is unnecessary, and the configuration of the fuel cell system is simple. In addition, since the temperature of the fuel cell is not increased unnecessarily, a simple safety measure system is sufficient.

  In the fuel cell operation method and the fuel cell system of the present invention, when the output voltage of the fuel cell becomes equal to or lower than a predetermined value, the hydrogen gas containing no cyclohexene is supplied to the fuel cell instead of the hydrogen gas containing cyclohexene. The output voltage of the battery can be kept above the predetermined value.

  In the fuel cell operating method and the fuel cell system of the present invention, the heat source cost can be reduced by using the warm drainage of the fuel cell as a heating heat source when cyclohexene is desorbed from the activated carbon.

It is a block diagram of a fuel cell system. It is a block diagram of another fuel cell system. It is a schematic diagram of the test apparatus of an Example. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result. It is a graph which shows an experimental result.

  Hereinafter, the present invention will be described in detail.

  The present invention relates to a method and apparatus for adsorbing and removing cyclohexene from hydrogen gas odorized with cyclohexene by activated carbon, wherein the activated carbon has an average pore diameter of 0.7 to 2.0 nm, preferably 0.8 to 1.5 nm. Preferably 0.85-1.2 nm is used. Activated carbon having an average pore size smaller than 0.7 nm has a small amount of saturated adsorption of cyclohexene. Moreover, those with an average pore diameter larger than 2.0 nm are not commercially available and are not easily available.

  Activated carbon may be granular, powdery, fibrous, or the like, but fibrous or granular is preferable because it is easy to handle.

  The cyclohexene concentration in the cyclohexene-containing hydrogen gas to be treated by the present invention is preferably 0.1 to 5000 ppm (volume ppm, hereinafter the same), particularly 1 to 300 ppm.

In the present invention, the cyclohexene-containing hydrogen gas is removed by adsorbing the cyclohexene to the activated carbon by bringing it into contact with activated carbon having the above average pore diameter at 60 ° C. or less, preferably from normal temperature to 60 ° C., particularly preferably at normal temperature. Preferably, activated carbon is filled in a container with a heating mechanism, and hydrogen gas containing cyclohexene is passed through the container at 60 ° C. or lower. The aeration rate of the cyclohexene-containing hydrogen gas is preferably about 10,000 to 30000 h ^−1, particularly about 10,000 to 15000 h ^{−1 in} terms of SV (space velocity).

  After the activated carbon has adsorbed cyclohexene, the activated carbon is heated to 70 to 90 ° C., preferably 70 to 85 ° C., particularly preferably 70 to 80 ° C., to desorb cyclohexene. This heating is preferably performed by a heating mechanism provided in the container. As the heating mechanism, in addition to an electric heater or the like, when warm water (for example, warm drainage) from the fuel cell system can be used, the warm water may be used. For example, a hot water pipe is wound around the container or a water jacket is provided, and warm water is passed through the hot water pipe or the water jacket to warm the activated carbon in the container to 70 ° C. or higher, thereby desorbing cyclohexene.

  When this desorption is performed, it is preferable that the cyclohexene-containing hydrogen gas is allowed to flow as it is into the container. The cyclohexene desorbed from the activated carbon is discharged out of the container together with the cyclohexene-containing hydrogen, and is oxidized by a catalytic oxidation device or the like, or supplied to the fuel cell. At the time of desorption, hydrogen gas not containing cyclohexene may be flowed into the container instead of cyclohexene-containing hydrogen gas.

  The method and apparatus for removing a hydrogen odorant according to the present invention can be suitably used for removing cyclohexene from hydrogen gas supplied to a fuel cell, and in particular, intermittently supply cyclohexene-free hydrogen gas to the fuel cell. The present invention is suitable for application to a fuel cell operating method and apparatus.

  That is, when the operation of taking out electric power from the fuel cell by supplying hydrogen gas containing cyclohexene to the fuel cell as the fuel gas is continued, the output voltage of the fuel cell gradually decreases, but when the output voltage of the fuel cell decreases It was found that the output voltage of the fuel cell was recovered when hydrogen gas containing no cyclohexene was supplied to the fuel cell. The fuel cell operating method and apparatus of the present invention are based on this finding.

  Next, the fuel cell operation method and the fuel cell system will be described in detail with reference to FIG.

  FIG. 1 is a configuration diagram of a fuel cell system using an odorant remover and a fuel cell. The cyclohexene-containing hydrogen gas is supplied to the fuel cell 3 through the gas supply line 1 and the valve 2. A valve 4, a line 5, an odorant removing device 6, a line 7, and a valve 8 are provided so as to bypass the valve 2. A line 9 branched from the line 7 is connected to the catalytic oxidation apparatus 11 via the valve 10. The odorant remover 6 is filled with activated carbon having an average pore diameter of 0.7 to 2 nm. A water jacket 6 a is provided on the outer periphery of the odorant remover 6, so that warm waste water from the fuel cell 3 can be circulated through the valve 12 and the pipe 13.

  The output voltage of the fuel cell 3 is detected by a voltmeter 15, and this detected voltage is input to the controller 16. The controller 16 includes a comparison circuit that compares a predetermined value set in advance with a detected voltage, and a valve drive control circuit.

  At the start of normal operation, the valve 2 is opened, the valves 4, 8, and 10 are closed, and the entire amount of hydrogen gas containing cyclohexene is supplied to the fuel cell 3 as it is to generate electric power. At this time, warm water is not circulated through the water jacket 6a, and the temperature of the odorant remover 6 is set to 60 ° C. or lower.

  When the output voltage of the fuel cell 3 was below a predetermined value, the valves 2 and 10 were closed, the valves 4 and 8 were opened, and the cyclohexene was removed by passing the cyclohexene-containing hydrogen gas through the odorant remover 6. Thereafter, the fuel cell 3 is supplied. The cyclohexene concentration in the hydrogen gas that has passed through the odorant remover 6 is preferably 10 ppm or less, particularly preferably 1 ppm or less.

  When hydrogen gas substantially free of cyclohexene that has passed through the odorant removing device 6 is supplied to the fuel cell 3 in this way, cyclohexene that has adhered to the fuel cell 3, particularly the catalyst of the fuel cell 3, or its decomposition. The product is removed by a physical removal action such as desorption or a chemical removal action, and the power generation voltage (output voltage) of the fuel cell is restored.

  When the fuel gas is hydrogen gas containing about 0.1 to 5000 ppm of cyclohexene and the fuel cell is a polymer electrolyte fuel cell, the cyclohexene-containing hydrogen gas is added to the fuel cell for 1 second to 1000 hours, particularly 10 seconds to After supplying for 1000 hours, especially 1 hour to 1000 hours, the cyclohexene-free hydrogen gas passed through the odorant remover 6 is supplied for 1 second to 100 hours, especially 10 seconds to 100 hours, especially 1 hour to 100 hours, and even 10 hours. The fuel cell output voltage can be sufficiently recovered by supplying about 100 hours.

  Thereafter, the valve 2 is opened, and the supply of the cyclohexene-containing hydrogen gas to the fuel cell 3 is restarted, and the activated carbon of the odorant remover 6 is desorbed while the cyclohexene-containing hydrogen gas is being supplied to the fuel cell 3. To process.

  In order to perform the desorption treatment of the activated carbon, the temperature of the activated carbon in the odorant remover 6 is set to 70 to 90 ° C., preferably 70 by flowing warm waste water from the fuel cell 3 to the water jacket 6a of the odorant remover 6. While heating to ˜85 ° C., particularly preferably 70 ° C. to 80 ° C., valves 4 and 10 are opened, valve 8 is closed, and a part of the cyclohexene-containing hydrogen gas from the pipe 1 is passed through the odorant remover 6. Then, cyclohexene-containing hydrogen gas accompanied by desorbed cyclohexene is supplied from the line 9 to the catalytic oxidation device 11 to oxidize cyclohexene and hydrogen.

  After the activated carbon in the odorant remover 6 has been desorbed for a predetermined time, the valves 4 and 10 are closed, and the entire amount of hydrogen gas containing cyclohexene from the pipe 1 is supplied to the fuel cell 3 as it is to return to normal operation. To do. When the output battery of the fuel cell 3 becomes equal to or lower than the predetermined voltage, the above process is performed to restore the output voltage, and then return to the steady operation.

  In the above description, the cyclohexene-free hydrogen gas is supplied to the fuel cell 3 when the output voltage of the fuel cell 3 drops below a predetermined value. However, even when the output voltage of the fuel cell 3 does not drop that much, it is intermittent. In addition, the hydrogen gas not containing cyclohexene may be supplied to the fuel cell 3 (for example, periodically) to suppress a decrease in the output voltage of the fuel cell 3.

  In the present invention, the supply speed when supplying the cyclohexene-free hydrogen gas to the fuel cell 3 may be made higher than when supplying the cyclohexene-containing hydrogen gas, and the output voltage of the fuel cell 3 may be recovered in a short time. Note that the fuel cell may be held in an open circuit while supplying the cyclohexene-free hydrogen gas to the fuel cell 3. Further, the supply amount of the hydrogen gas not containing cyclohexene may be increased while temporarily maintaining the generated voltage.

  In the present invention, a tank for temporarily storing hydrogen gas subjected to cyclohexene removal treatment may be provided. The tank may be filled with a hydrogen storage alloy. The hydrogen gas in the tank may be supplied to the fuel cell at a higher supply rate than the supply rate during steady operation.

  In FIG. 1, only one odorant remover 6 is installed, but a plurality of odorant removers 6 may be installed in parallel so that cyclohexene-containing hydrogen gas passes alternately. FIG. 2 is a system diagram of a fuel cell system in which two odorant removers 23 and 33 are provided side by side.

  The supply pipe 20 of the cyclohexene-containing hydrogen gas is branched into pipes 21 and 31. The pipe 21 is connected to the fuel cell 29 via a valve 22, an odorant remover 23, a pipe 24, a valve 25, and a pipe 26. A pipe 28 having a valve 27 branches from the pipe 24, and the gas from the odorant remover 23 can be supplied from the pipe 28 to the catalytic oxidation device 39 through the pipe 36.

  The pipe 31 is connected to the catalytic oxidation device 39 via a valve 32, an odorant remover 33, a pipe 34, a valve 35, and a pipe 36. A pipe 38 having a valve 37 is branched from the pipe 34, and the gas from the odorant remover 33 can be supplied from the pipe 38 to the fuel cell 29 through the pipe 26.

  The output voltage of the fuel cell 29 is detected by a voltmeter 40, and this detected voltage is input to the valve controller 41. The odorant removers 23 and 33 are filled with activated carbon having an average pore diameter of 0.7 to 2.0 nm, respectively. The odorant removers 23 and 33 are provided with water jackets 23a and 33a, respectively, to add activated carbon to 70 ° C. or higher by circulating the warm drainage of the fuel cell 29 through a hot water pipe (not shown in FIG. 2). It is configured to be warm.

  In the first operation step, the valves 22, 25 are opened, the valves 32, 35, 27, 37 are closed, and the cyclohexene-containing hydrogen gas is supplied to the fuel cell 29 through the odorant remover 23 and the pipes 24, 26. Generate electricity. It should be noted that warm water is not passed through the water jackets 23a and 33a, and the activated carbon temperature in the odorant removers 23 and 33 is 60 ° C. or lower.

  When the output voltage of the fuel cell 29 becomes lower than the set voltage, the process proceeds to the second operation step, the valves 32 and 37 are opened, the valves 25 and 35 are closed, and the cyclohexene-containing hydrogen gas from the main pipe 20 is closed. Most of the fuel is supplied to the fuel cell 29 through the odorant remover 33 and the pipes 34, 38, and 26 to generate electricity.

  At least in the initial stage of the second operation process, the warm drainage from the fuel cell 29 is caused to flow into the water jacket 23a, the activated carbon temperature in the odorant remover 23 is set to 70 ° C. or higher, cyclohexene is desorbed, and the valves 22, 27 is opened, a part of the cyclohexene-containing hydrogen gas from the main pipe 20 is passed through the odorant remover 23, and the hydrogen gas containing the desorbed cyclohexene is supplied to the catalytic oxidation apparatus 39 via the pipes 24, 28 and 36. Introduced and oxidized. It is preferable to perform the desorption process of the odorant remover 23 for a time required for the desorption that has been obtained in advance. After the desorption is completed, the valves 22 and 27 are closed.

  When the second operation process is continued, the output voltage of the fuel cell 29 gradually decreases. When this output voltage becomes equal to or lower than the predetermined voltage, the process returns to the first operation process. At least at the initial stage after returning from the second operation step to the first operation step, the valves 32 and 35 are opened, the valve 37 is closed, and a part of the cyclohexene-containing hydrogen gas from the main pipe 20 is removed by the odorant remover 33. The activated carbon in the odorant remover 33 is heated to 70 ° C. or more by flowing the warm waste water from the fuel cell 29 to the water jacket 33a. Thereby, cyclohexene is desorbed from the activated carbon in the odorant remover 33. Hydrogen gas containing desorbed cyclohexene is introduced into the catalytic oxidation device 39 through the pipes 34 and 36, and is oxidized. After the desorption is completed, the valves 32 and 35 are closed.

  The fuel cell 29 can be continuously operated by alternately performing the first operation step and the second operation step, and performing cyclohexene desorption treatment while performing cyclohexene adsorption removal on one of the odorant removers 23 and 33. it can.

  In this description, the first operation process and the second operation process are switched when the output voltage of the fuel cell 29 becomes a predetermined voltage or lower. However, the cyclohexene desorption process of the odorant removing device during the desorption process is performed. If completed, the first and second operation steps may be switched. In this way, it is possible to always supply hydrogen gas containing no cyclohexene or having a low cyclohexene concentration to the fuel cell 29.

  The fuel cell used in the present invention includes a solid polymer fuel cell, a phosphoric acid fuel cell, a molten carbonate fuel cell, a solid oxide fuel cell, and an alkaline electrolyte fuel cell. A molecular fuel cell or an alkaline electrolyte fuel cell is preferred. This polymer electrolyte fuel cell usually has a cell stack in which a plurality of cells are stacked. Each cell includes a solid polymer electrolyte membrane, a fuel electrode (anode) and an air electrode (oxidizer electrode: cathode) that sandwich the solid polymer electrolyte membrane from both sides, and a fuel electrode side separator and air that sandwich the fuel electrode and air electrode. It consists of a pole-side separator.

  The fuel electrode has a diffusion layer and a catalyst layer. A fuel gas containing hydrogen such as hydrogen gas or hydrogen rich gas is supplied to the fuel electrode by the fuel supply system. The fuel gas supplied to the fuel electrode is diffused in the diffusion layer and reaches the catalyst layer. In the catalyst layer, hydrogen is separated into protons (hydrogen ions) and electrons. Hydrogen ions move to the air electrode through the solid polymer electrolyte membrane, and electrons move to the air electrode through an external circuit. As the catalyst, platinum is usually used, but is not limited thereto, and may be a platinum alloy or a non-platinum catalyst.

The air electrode has a diffusion layer and a catalyst layer, and an oxidant gas such as air is supplied to the air electrode by an oxidant supply system. The oxidant gas supplied to the air electrode is diffused in the diffusion layer and reaches the catalyst layer. In the catalyst layer, water is generated by a reaction between the oxidant gas, hydrogen ions that have reached the air electrode through the solid polymer electrolyte membrane, and electrons that have reached the air electrode through the external circuit. The electrons passing through the external circuit during the reaction at the fuel electrode and the air electrode are used as electric power for a load connected between both terminals of the fuel cell stack.
In the above embodiment, the warm drainage of the fuel cell is used as a heat source for heating the activated carbon adsorbed with cyclohexene, but it may be exhaust heat from other devices, or an electric heater or the like may be used. .

  Hereinafter, experimental examples, examples, and comparative examples will be described.

[Experimental Example 1 (Fuel cell output reduction and recovery experiment with cyclohexene)]
The fuel cell was operated by supplying hydrogen gas with cyclohexene added to the fuel cell and intermittently supplying hydrogen gas without cyclohexene. Specifically, a JARI (Japan Automobile Research Institute) standard cell having a membrane / electrode assembly (MEA) with an electrode area of 25 cm ² (5 cm square) was operated as a single cell. The catalyst of MEA is TEC10E50E, and the amount of catalyst is 0.2 mg Pt / cm ² for both electrodes. The electrolyte membrane is Nafion (registered trademark) NRE211.

The current density was kept constant at 0.25 A / cm ² and was controlled so as to always have the same current density during the addition of cyclohexene. The fuel utilization rate (Uf) was 90%, and the air utilization rate (Uo) was 55%. The cell temperature was 65 ° C., and the humidification dew point of the gas flowing through the anode and cathode was both 65 ° C.

  Hydrogen gas having a cyclohexene concentration of 5000 ppm was prepared and added to the hydrogen gas after humidification so that the cyclohexene concentration was 100 ppm. FIG. 3 shows an outline of the test apparatus.

  For the power generation characteristic evaluation of the fuel cell, AUTOPEM manufactured by Toyo Corporation was used.

  Until 535 hours passed from the start of operation of the fuel cell, hydrogen gas without addition of cyclohexene was supplied to the fuel cell. Thereafter, hydrogen gas containing 100 ppm of cyclohexene was supplied for 406 hours. Subsequently, after adding cyclohexene-free hydrogen gas for 2 hours, 100 ppm of cyclohexene-added hydrogen gas was supplied for 837 hours. Further, after that, cyclohexene-free hydrogen gas was supplied for 600 hours.

  The change with time of the output voltage of the fuel cell is shown in FIG. As shown in FIG. 4, when the addition of cyclohexene was started after 535 hours, the cell voltage gradually decreased. After adding 406 hours of cyclohexene, the cell voltage was recovered by supplying hydrogen gas without cyclohexene added for 2 hours. Thereafter, after the cyclohexene addition operation for 837 hours, when the addition of cyclohexene was stopped, the cell voltage was recovered again. In addition, when cyclohexene addition is restarted and then the supply of hydrogen gas without addition of cyclohexene is continued, the cell voltage becomes an extrapolated line (dotted line) level of the cell voltage transition at the initial stage when cyclohexene is not mixed. It was.

  From the above, it was confirmed that when the operation was continued by supplying the cyclohexene-containing hydrogen gas, the cell voltage decreased, but it was reversibly recovered by circulating the hydrogen gas without addition of cyclohexene.

[Example 1]
As the activated carbon, 0.27 g (about 0.5 cm ³ ) of A7 manufactured by Unitika Co., Ltd. (fibrous activated carbon, average pore diameter 0.70 nm) is packed in a 5 mm diameter column, and an electric heater is wrapped around the column to activate the activated carbon. Heating was possible.

After the activated carbon was heated to 60 ° C., cyclohexene-added hydrogen gas (cyclohexene concentration: 5000 ppm) was bubbled through the column at 50 mL / min (SV = 10000 h ⁻¹ ) for 1 h, and then cyclohexene-added hydrogen gas was allowed to flow at the same flow rate. The activated carbon temperature was raised to 70 ° C. and maintained for 2 hours. Then, with the cyclohexene-added hydrogen gas flowing at the same flow rate, the activated carbon temperature is returned to 60 ° C. and maintained for 1 h, and then the activated carbon temperature is raised to 70 ° C. with the cyclohexene-added hydrogen gas flowing at the same flow rate. And held for 2 h. Next, similarly, the activated carbon temperature was maintained at 60 ° C. for 1 hour and maintained at 70 ° C. for about 2 hours while the cyclohexene-added hydrogen gas was allowed to flow at the same flow rate. Thereafter, holding the cyclohexene-added hydrogen gas at the same flow rate, holding at 60 ° C. for 1 h and holding at 80 ° C. for about 2 h were repeated.

  The change with time of the cyclohexene concentration in the column effluent gas during this period is shown in FIG.

[Example 2]
The same experiment as in Example 1 was performed except that a fibrous activated carbon having an average pore diameter of 0.89 nm (A10 manufactured by Unitika Co., Ltd.) was used as the activated carbon. FIG. 6 shows the change with time of the cyclohexene concentration in the column effluent gas.

[Example 3]
The same experiment as in Example 1 was performed except that a fibrous activated carbon having an average pore diameter of 1.09 nm (A15 manufactured by Unitika Co., Ltd.) was used as the activated carbon. FIG. 7 shows changes with time of the cyclohexene concentration in the column effluent gas.

[Example 4]
The same experiment as in Example 1 was performed except that a fibrous activated carbon having an average pore diameter of 1.13 nm (A20 manufactured by Unitika Ltd.) was used as the activated carbon. FIG. 8 shows the change with time of the cyclohexene concentration in the column effluent gas.

[Example 5]
A commercially available fibrous activated carbon (trade name GT10) having an average pore diameter of 1.74 nm was used as the activated carbon, packed in the same column as in Example 1, and cyclohexene-added hydrogen gas (cyclohexene concentration 5000 ppm) at 50 ° C. at 50 mL / min ( SV = 10000 h ⁻¹ ), the column was vented for 1 h, and the activated carbon temperature was raised to 70 ° C. and held for 2 h while the cyclohexene-added hydrogen gas was flowing at the same flow rate, and then the activated carbon temperature was lowered to 60 ° C. The activated carbon temperature was then raised to 80 ° C. and held for 1 h. FIG. 9 shows the change with time of the cyclohexene concentration in the column effluent gas.

[Comparative Example 1]
The column was filled with 0.2 g of fibrous activated carbon (A5 manufactured by Unitika Co., Ltd.) having an average pore diameter of 0.65 nm, and hydrogen gas with a cyclohexene concentration of 5000 ppm was vented at 50 mL / min (SV = 12000 h ⁻¹ ). The temperature was set to 30 ° C. for about 10 hours from the start of aeration, and then the column was heated to 60 ° C. with an electric heater for 3 hours, and then heated to 400 ° C. over 2 hours. FIG. 10 shows the change with time of the cyclohexene concentration in the column outflow hydrogen gas.

[Comparative Example 2]
The same experimental apparatus as in Example 1 was used except that a fibrous activated carbon having an average pore diameter of 4.73 nm (Kanebo Co., Ltd. MG9) was used as the activated carbon. Then, in the same manner as in Example 1, while the activated carbon was heated to 60 ° C., cyclohexene-added hydrogen gas (cyclohexene concentration: 5000 ppm) was passed through the column at 50 mL / min (SV = 10000 h ⁻¹ ) for 1 h. Subsequently, the activated carbon temperature was raised to 70 ° C. and maintained for 1 h while the cyclohexene-added hydrogen gas was allowed to flow at the same flow rate. FIG. 11 shows the change with time of the cyclohexene concentration in the column effluent gas during this period.

[Comparative Example 3]
The same experiment as Comparative Example 2 was performed except that the temperature rise temperature after ventilation at 60 ° C. × 1 h was 80 ° C. FIG. 12 shows the change with time of the cyclohexene concentration in the column effluent gas.

[Discussion]
(1) As shown in FIG. 5, in Example 1, desorption of cyclohexene started immediately when the activated carbon temperature was raised from 60 ° C. to 70 ° C. 1 h after the start of operation. From this, in Example 1, it is surmised that the activated carbon was almost saturated in the operation 1h.

(2) In Example 1, when the activated carbon temperature was raised from 60 ° C. to 70 ° C. or 80 ° C. after about 4 h, 7 h, 10 h, 13 h, and 16 h after the start of operation, the cyclohexene concentration immediately after this temperature rise It is estimated that the desorption of cyclohexene progressed at this time.

(3) In Example 1, when the activated carbon temperature was lowered from 70 ° C. to 60 ° C. after about 3 h, 6 h, and 9 h after the start of operation, the cyclohexene concentration decreased to 0 ppm for a very short time, and immediately thereafter the cyclohexene concentration Increases to 5000 ppm. This is because cyclohexene is desorbed to some extent from activated carbon during 2 hours at 70 ° C, and activated carbon adsorbs cyclohexene immediately after the activated carbon temperature is lowered from 70 ° C to 60 ° C. This is considered to be due to the saturated adsorption state.

(4) In Example 1, when the desorption temperature was 80 ° C., the cyclohexene concentration was reduced to 0 ppm immediately after the activated carbon temperature was lowered from 80 ° C. to 60 ° C., and the 0 ppm maintenance time was 70 ° C. → It is longer than the 0 ppm maintenance time when the temperature drops to 60 ° C. This is presumably because the desorption amount from the activated carbon was increased by increasing the desorption temperature to 80 ° C.

(5) In Examples 2 to 4, even if the activated carbon temperature was raised from 60 ° C. to 70 ° C. 1 h after the start of operation, the cyclohexene concentration was maintained at 0 ppm for a while thereafter. This is considered to be because the activated carbon used in Examples 2 to 4 has a large amount of saturated adsorption of cyclohexene, and thus adsorption of cyclohexene has continued. The maintenance time of the cyclohexene concentration of 0 ppm becomes longer in the order of Examples 2, 3 and 4, which is considered to be proportional to the saturated adsorption amount of cyclohexene of each activated carbon.

(6) In Examples 2 to 4, when the activated carbon temperature is lowered to 70 ° C. → 60 ° C. or 80 ° C. → 60 ° C., the cyclohexene concentration decreases to almost 0 ppm, and then gradually increases to 5000 ppm. During this rise from 0 ppm to 5000 ppm, cyclohexene is adsorbed on the activated carbon. The amount of cyclohexene adsorbed increases in the order of Examples 2, 3, and 4.

(7) In Examples 2 to 4, when the activated carbon temperature is raised to 60 ° C. → 70 ° C. or 60 ° C. → 80 ° C., the cyclohexene concentration in the column effluent gas increases rapidly, and then the cyclohexene concentration gradually decreases. During this time, cyclohexene is desorbed. This desorption amount increases in the order of Examples 2, 3, and 4.

(8) In any of Examples 2 to 4, the amount of desorption is higher when the temperature is raised by 80 ° C than when the temperature is raised by 70 ° C.

(9) In Example 5, after 0.5 h after the start of operation, saturated adsorption occurs, and after 3 h, when the activated carbon temperature is lowered from 70 ° C. to 60 ° C., the cyclohexene concentration decreases slightly by about 0.5 h, and then the cyclohexene concentration decreases. It rises to 5000 ppm. This is because cyclohexene is desorbed to some extent from activated carbon during 2 hours at 70 ° C, and activated carbon adsorbs cyclohexene immediately after the activated carbon temperature is lowered from 70 ° C to 60 ° C. This is considered to be due to the saturated adsorption state.

  In Example 5, when the desorption temperature was 80 ° C., the cyclohexene concentration peaked immediately after the activated carbon temperature was raised to 80 ° C., and the desorption of cyclohexene proceeded at this time. Conceivable.

(10) In Comparative Example 1, as shown in FIG. 10, it is considered that saturation adsorption has been reached in about 0.5 h since breakthrough has started about 0.5 h after the start of ventilation. Since the temperature is kept at 30 ° C. for 0.5 h to about 10 h after the start of aeration, the cyclohexene concentration in the effluent gas is 5000 ppm, and no adsorption occurs. When the column is heated to 60 ° C. after about 10 hours, the desorption of cyclohexene starts, and the desorption is completed in about 2 h. Thereafter, no desorption is observed even when the temperature is raised to 400 ° C., so it is considered that all the cyclohexene adsorbed at 30 ° C. was desorbed under the holding condition at 60 ° C. Therefore, when activated carbon with a small average pore diameter of 0.65 nm is used, the amount of cyclohexene adsorbed is small, and desorption occurs even at 60 ° C., so that cyclohexene is not adsorbed when the activated carbon is heated. Was recognized.

(11) In Comparative Examples 2 and 3, no adsorption of cyclohexene occurred at any of 60 ° C to 80 ° C. This is presumably because the pore diameter of the activated carbon is too large.

  Table 1 summarizes the evaluation results of Examples 1 to 5 and Comparative Examples 1, 2, and 3.

3,29 Fuel cell 6,23,33 Odorant remover 6a, 23a, 33a Water jacket 11,39 Catalytic oxidation device 15 Voltmeter 16,41 Controller

Claims (10)

In the method for removing the hydrogen odorant, the cyclohexene-containing hydrogen gas is brought into contact with the activated carbon and the cyclohexene is adsorbed and removed by the activated carbon.
A method for removing a hydrogen odorant, wherein the activated carbon has an average pore diameter of 0.70 to 2.0 nm.   The method for removing a hydrogen odorant according to claim 1, wherein the adsorption treatment of cyclohexene is performed at 60 ° C or lower, and the desorption treatment of cyclohexene is performed at 70 to 90 ° C. In an apparatus for removing a hydrogen odorant, a cyclohexene-containing hydrogen gas is brought into contact with activated carbon to remove cyclohexene by adsorbing the activated carbon on the activated carbon.
An apparatus for removing a hydrogen odorant, wherein the activated carbon has an average pore diameter of 0.70 to 2.0 nm.   4. The apparatus for removing a hydrogen odorant according to claim 3, further comprising temperature control means for performing adsorption treatment of cyclohexene at 60 [deg.] C. or less and performing desorption treatment of cyclohexene at 70 to 90 [deg.] C. In a method of operating a fuel cell, the method includes the step of supplying the cyclohexene-containing hydrogen gas to the fuel cell to generate power,
A method of intermittently supplying a cyclohexene-free hydrogen gas to the fuel cell to recover the output voltage,
A method for operating a fuel cell, comprising using, as the hydrogen gas containing no cyclohexene, hydrogen gas subjected to cyclohexene removal treatment by the method for removing a hydrogen odorant according to claim 1 or 2.   6. The method of operating a fuel cell according to claim 5, wherein the hydrogen gas containing no cyclohexene is supplied to the fuel cell when the output voltage of the fuel cell becomes a predetermined value or less.   7. The method of operating a fuel cell according to claim 5, wherein the warm drainage of the fuel cell is used as a heating heat source when the activated carbon adsorbing cyclohexene is heated and desorbed. In a fuel cell system for generating power by supplying cyclohexene-containing hydrogen gas to a fuel cell,
The apparatus for removing a hydrogen odorant according to claim 3 or 4,
A fuel cell system comprising: means for intermittently supplying hydrogen gas that has been subjected to cyclohexene removal treatment by the apparatus to the fuel cell to restore the output voltage.   9. The fuel cell system according to claim 8, wherein the means supplies the cyclohexene-free hydrogen gas to the fuel cell when the output voltage of the fuel cell becomes a predetermined value or less.   10. The fuel cell system according to claim 8 or 9, wherein the warm drainage of the fuel cell is used as a heating heat source when the activated carbon adsorbing cyclohexene is heated and desorbed.

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