JP5337553B2 - Desulfurization apparatus and fuel cell system - Google Patents

Description

  The present invention relates to a desulfurization device that removes sulfur from liquid fuel, and a fuel cell system including such a desulfurization device.

  In the fuel cell system, a reformer containing hydrogen is generated by the reformer, and power is generated by using the reformed gas by the fuel cell stack. Such a fuel cell system includes a desulfurizer that removes sulfur from the liquid fuel in order to prevent deterioration of the reforming catalyst when liquid fuel such as kerosene is supplied to the reformer as a reforming raw material. It is necessary to provide (for example, refer patent document 1).

JP 2007-332318 A

  The desulfurizer of Patent Document 1 is provided with an electric heater such as a sheathed heater as a heating means for promoting the desulfurization process. Specifically, an electric heater is wound around the outer peripheral surface of the desulfurizer so that the interval between adjacent windings is constant and spiral. Therefore, the liquid fuel in the desulfurizer is heated evenly in the axial direction of the desulfurizer. In this case, in the central part in the axial direction of the desulfurizer (the part between the inlet side and the outlet side of the desulfurizer), heat is less likely to escape than in other parts, so the center of the liquid fuel in the desulfurizer The part becomes the hottest.

  However, the desulfurization reaction is different between the inlet side and the outlet side of the desulfurizer, and the reaction tends to occur at a higher temperature on the inlet side, and the reaction tends to occur even at a higher temperature on the outlet side. Therefore, in the desulfurizer of Patent Document 1 described above, the liquid fuel becomes relatively cold at the inlet side, and the liquid fuel may not be sufficiently desulfurized, and the liquid fuel becomes relatively hot at the central portion. Therefore, there has been a problem that the desulfurization agent (desulfurization catalyst) is heated more than necessary and the life of the desulfurization catalyst is shortened.

  Then, an object of this invention is to provide the desulfurization apparatus and fuel cell system which can suppress the lifetime reduction of a desulfurization catalyst, aiming at acceleration | stimulation of desulfurization reaction.

  A desulfurization apparatus according to the present invention includes a cylindrical desulfurizer that contains a desulfurization catalyst that removes sulfur from a liquid fuel to be supplied to a reformer that generates a reformed gas containing hydrogen, and an interior of the desulfurizer. A heater for heating the liquid fuel and a power source for energizing the heater. The desulfurizer has an inlet region on the inlet side of the liquid fuel in the outer periphery of the desulfurizer, and the heater has a spiral shape. It is wound around the outer periphery of the desulfurizer, and the interval between adjacent windings of the heater is set to be the smallest in the inlet region.

  In the desulfurization apparatus according to the present invention, the heater is wound around the outer periphery of the desulfurizer so as to have a spiral shape, and the interval between adjacent windings of the heaters is set to be the smallest in the inlet region. Yes. Therefore, when the heater is energized, the inlet side of the desulfurizer is heated most. As a result, the liquid fuel tends to be relatively hot at the inlet side of the desulfurizer, and therefore, the desulfurization reaction at the inlet side of the desulfurizer can be promoted. In addition, since the liquid fuel tends to be relatively low in the downstream stage from the inlet side of the desulfurizer, the desulfurization catalyst is not heated more than necessary. As a result, it is possible to suppress the life reduction of the desulfurization catalyst. Furthermore, since the number of turns of the heater is relatively reduced in the subsequent stage from the inlet side of the desulfurizer, it is possible to reduce the power consumption of the heater. Furthermore, since the temperature distribution of the liquid fuel in the desulfurizer can be controlled by a simple configuration of one heater and one power source, it is possible to reduce costs associated with simplification of the desulfurization apparatus.

  Preferably, the desulfurizer has an outlet region on the outlet side of the liquid fuel in the outer periphery of the desulfurizer, and a central region between the inlet region and the outlet region in the outer periphery of the desulfurizer, and is adjacent to the heater. The interval between the matching windings is set to be the largest in the central region, and is set to be larger than the inlet region and smaller than the central region in the outlet region. If it does in this way, it will become easy to heat liquid fuel in order of the entrance side of a desulfurizer, the exit side, and a central part (ease of heating of liquid fuel: inlet side> outlet side> central part). Here, in the central portion of the desulfurizer (the portion between the inlet side and the outlet side of the desulfurizer), heat is less likely to escape than other portions. Therefore, the temperature of the liquid fuel is low at the central portion of the desulfurizer that is most difficult to be heated, the inlet side of the desulfurizer that is most easily heated, and the outlet side of the desulfurizer that is relatively easy to be heated. Almost equal. As a result, the temperature distribution of the liquid fuel in the desulfurizer can be made substantially uniform. Further, since the number of turns of the heater is relatively reduced in the central region and the outlet region of the desulfurizer, the power consumption of the heater can be reduced.

  Preferably, the desulfurizer has an outlet region on the outlet side of the liquid fuel in the outer periphery of the desulfurizer, and a central region between the inlet region and the outlet region in the outer periphery of the desulfurizer, and is adjacent to the heater. The interval between the matching windings is set to be larger than the entrance region in the central region, and no heater is wound around the exit region. If it does in this way, it will become easy to heat liquid fuel in the order of the entrance side of a desulfurizer, a central part, and an outlet side (ease of heating of liquid fuel: inlet side> central part> outlet side). Therefore, the temperature of the liquid fuel in the desulfurizer increases as it goes from the outlet side to the inlet side of the desulfurizer. As a result, it is possible to suppress the life reduction of the desulfurization catalyst while promoting the desulfurization reaction, and it is possible to reduce the power consumption of the heater by not winding the heater around the outlet region of the desulfurizer. Become.

  Preferably, the desulfurizer has an outlet region on the liquid fuel outlet side of the outer periphery of the desulfurizer, and the interval between adjacent windings of the heater is set to be larger than the inlet region in the central region. Has been. If it does in this way, it will become easy to heat liquid fuel in the order of the inlet side of a desulfurizer, and an outlet side (ease of heating of liquid fuel: inlet side> outlet side). Therefore, the temperature of the liquid fuel in the desulfurizer increases as it goes from the outlet side to the inlet side of the desulfurizer. As a result, while promoting the desulfurization reaction, it is possible to suppress a decrease in the life of the desulfurization catalyst and reduce the power consumption of the heater by relatively reducing the number of turns of the heater in the outlet region of the desulfurizer. It becomes possible to do.

  On the other hand, a fuel cell system according to the present invention includes any one of the above-described desulfurization apparatuses, a reformer that generates a reformed gas containing hydrogen using a liquid fuel from which sulfur content has been removed by the desulfurization apparatus, and a reformer. And a fuel cell stack for generating power using the reformed gas generated by the mass device.

  According to the fuel cell system of the present invention, since any one of the desulfurization apparatuses described above is provided, it is possible to suppress a decrease in the life of the desulfurization catalyst while promoting the desulfurization reaction.

  ADVANTAGE OF THE INVENTION According to this invention, the desulfurization apparatus and fuel cell system which can suppress the lifetime reduction of a desulfurization catalyst can be provided, aiming at acceleration | stimulation of desulfurization reaction.

FIG. 1 is a diagram schematically showing a fuel cell system according to the present embodiment. FIG. 2 is a diagram schematically showing an example (first example) of a desulfurization device provided in the fuel cell system according to the present embodiment. FIG. 3 is a diagram schematically showing an example (second example) of the desulfurization apparatus provided in the fuel cell system according to the present embodiment. FIG. 4 is a diagram schematically illustrating an example (third example) of the desulfurization device provided in the fuel cell system according to the present embodiment. FIG. 5 is a diagram schematically illustrating an example (fourth example) of a desulfurization device included in the fuel cell system according to the present embodiment.

  A preferred embodiment of a fuel cell system 1 according to the present invention will be described with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and a duplicate description is omitted.

  As shown in FIG. 1, the fuel cell system 1 includes a reformer 2 that generates reformed gas containing hydrogen, and a desulfurizer 3 that removes sulfur from the liquid fuel supplied to the reformer 2. And a fuel cell stack 4 that generates electric power using the reformed gas generated by the reformer 2. The fuel cell system 1 is used as, for example, a household power supply source, and kerosene is used as a liquid fuel from the viewpoint that it can be easily obtained and stored independently. Yes.

  The reformer 2 includes a reformer 5 that generates a reformed gas by steam reforming a liquid fuel, and a burner 6 that heats the reforming catalyst accommodated in the reformer 5. The burner 6 heats the reforming catalyst that promotes the steam reforming reaction, thereby supplying the reforming catalyst with heat necessary for effectively exhibiting the catalytic reaction. In the reformer 5, the liquid fuel introduced from the desulfurization apparatus 3 is vaporized to become a raw material gas, and the reforming catalyst promotes a steam reforming reaction between the raw material gas and steam (water), thereby improving the hydrogen-rich reforming. A quality gas is produced.

  The desulfurization apparatus 3 includes a desulfurizer 7, a heater 8, a power source 9, and a control unit 15. The desulfurizer 7 has a cylindrical shape, and inside the desulfurizer 7 is a desulfurization catalyst (not shown) that removes sulfur from the liquid fuel to be supplied to the reformer 5, and a temperature such as a thermocouple. A total of 13 is provided.

  As shown in FIGS. 1 and 2, in the present embodiment, liquid fuel is supplied from the lower end of the desulfurizer 7 into the desulfurizer 7, and the liquid fuel from which the sulfur content has been removed is present at the upper end of the desulfurizer 7. It is configured to flow to the storage container 19 through the connected liquid fuel circulation line 16 (so-called upflow). Therefore, as shown in FIG. 2, the desulfurizer 7 is positioned on the liquid fuel inlet side of the outer periphery of the desulfurizer 7 and on the liquid fuel outlet side of the outer periphery of the desulfurizer 7. It has an outlet region B and a central region C located between the liquid fuel inlet region A and the outlet region B on the outer periphery of the desulfurizer 7. In the present embodiment, the length of the inlet region A in the axial direction of the desulfurizer 7, the length of the central region C in the axial direction of the desulfurizer 7, and the length of the outlet region B in the axial direction of the desulfurizer 7 are: Both are set to be substantially equal.

  The heater 8 is an electric heater such as a sheathed heater and is provided on the outer periphery of the desulfurizer 7. Specifically, as shown in FIGS. 1 and 2, the heater 8 is spirally wound around the outer periphery of the desulfurizer 7. Thereby, the desulfurizer 7 is heated by the heater 8 from the outer surface side, and the desulfurization process of the liquid fuel is promoted.

  In the present embodiment, the interval between adjacent windings in the heater 8 is set to be the smallest in the entrance region A, and is set to be the largest in the central region C, and in the exit region B. It is set to be larger than the entrance area A and smaller than the central area C (see FIG. 2).

  The power source 9 applies electric power converted from the fuel cell stack 4 to alternating current to the heater 8 and energizes the heater 8. The thermometer 13 is disposed in the lower part of the desulfurizer 7, measures the temperature of the desulfurization catalyst in the desulfurizer 7, and transmits an electric signal indicating the temperature to the control unit 15. The control unit 15 controls ON / OFF of the power source 9 based on the temperature measured by the thermometer 13.

  The fuel cell stack 4 is a polymer electrolyte fuel cell stack configured by stacking a plurality of battery cells, and generates power using the reformed gas obtained by the reformer 2. Each battery cell has an anode, a cathode, and a polymer ion exchange membrane that is an electrolyte disposed between the anode and the cathode. In each battery cell, the reformed gas is introduced into the anode and air is introduced into the cathode, and an electrochemical power generation reaction is performed.

  As shown in FIGS. 1 and 2, one end of a liquid fuel circulation line 16 is connected to the upper end of the desulfurizer 7, and the other end of the liquid fuel circulation line 16 is disposed above the desulfurization device 3. The storage container 19 is connected to the side wall. On the bottom wall of the storage container 19, a liquid fuel distribution line 23 provided with a pump 22 for introducing the liquid fuel stored downward in the storage container 19 into the reformer 5, and the liquid fuel is supplied to the burner 6. A liquid fuel distribution line 25 provided with a pump 24 for introduction into is connected. The burner 6 is connected to an air circulation line 27 provided with a pump 26 for introducing air into the burner 6. Thus, by temporarily storing the liquid fuel in the storage container 19, the supply of the liquid fuel to the reformer 5 by the pump 22 and the supply of the liquid fuel to the burner 6 by the pump 24 can be stabilized. .

  In the fuel cell system 1 configured as described above, first, liquid fuel is introduced into the desulfurizer 7 of the desulfurization device 3 at a flow rate of, for example, about 3 g / min to 10 g / min, and in a high temperature / high pressure state. The sulfur content is removed by the desulfurization catalyst. The liquid fuel derived from the desulfurizer 7 is stored in the storage container 19 through the liquid fuel distribution line 16. The liquid fuel stored in the storage container 19 is introduced into the reformer 5 via the liquid fuel distribution line 23. At this time, liquid fuel is introduced into the burner 6 through the liquid fuel circulation line 25 and air is introduced through the air circulation line 27. Thereby, in the reformer 5, the reforming catalyst is heated by the burning burner 6, and the reformed gas is generated using the liquid fuel. The reformed gas generated by the reformer 5 is introduced into the fuel cell stack 4, and the fuel cell stack 4 generates power using the reformed gas.

  In the present embodiment as described above, the heater 8 is wound around the outer periphery of the desulfurizer 7 so as to be spiral, and the interval between adjacent windings in the heater 8 is the smallest in the inlet region A. It is set so as to be the largest in the central region C, and is set so as to be larger than the inlet region A and smaller than the central region C in the outlet region B. Therefore, when the heater 8 is energized, the liquid fuel is easily heated in the order of the inlet region A, the outlet region B, and the central region C of the desulfurizer (ease of heating the liquid fuel: inlet region A> outlet region B). > Center region C). Here, in the central region C of the desulfurizer 7, heat is less likely to escape as compared with other portions. Therefore, in any of the central region C of the desulfurizer 7 that is most difficult to be heated, the inlet region A of the desulfurizer 7 that is most easily heated, and the outlet side of the desulfurizer 7 that is relatively easily heated. The temperature of liquid fuel becomes substantially equal. As a result, since the temperature distribution of the liquid fuel in the desulfurizer 7 becomes substantially uniform, the desulfurization reaction on the inlet side of the desulfurizer 7 can be promoted. In addition, since the number of turns of the heater 8 is relatively reduced in the subsequent stage from the inlet side of the desulfurizer 7, the power consumption of the heater 8 can be reduced. Furthermore, since the temperature distribution of the liquid fuel in the desulfurizer 7 can be controlled by a simple configuration of one heater 8 and one power source 9, it is possible to reduce costs associated with simplification of the desulfurization apparatus 3. .

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments. For example, as shown in FIG. 3, the heater 8 is not wound around the outlet region B, and the interval between adjacent windings in the heater 8 is set to be larger in the central region C than in the inlet region A. Also good. If it does in this way, it will become easy to heat a liquid fuel in order of the entrance area A of the desulfurizer 7, the center area | region C, and the exit area | region B (Easiness of heating of liquid fuel: Inlet area A> center area C> outlet area) B). Therefore, since the temperature of the liquid fuel in the desulfurizer 7 increases from the outlet region B of the desulfurizer 7 toward the inlet region A (the liquid fuel tends to be relatively low in the latter stage than the inlet side of the desulfurizer 7. Therefore, the desulfurization catalyst is not heated more than necessary. As a result, the desulfurization reaction can be promoted and the life reduction of the desulfurization catalyst can be suppressed, and the heater 8 is not wound around the outlet region B of the desulfurizer 7, thereby reducing the power consumption of the heater 8. It becomes possible.

  Further, as shown in FIG. 4, the outer periphery of the desulfurizer 7 is divided into an inlet region A and an outlet region B, and an interval between adjacent windings of the heater 8 is set in the outlet region B from the inlet region A. May be set to be larger. If it does in this way, it will become easy to heat a liquid fuel in order of the entrance area A of the desulfurizer 7, and the exit area | region B (easiness of a liquid fuel being heated: entrance area A> exit area B). Therefore, since the temperature of the liquid fuel in the desulfurizer 7 increases from the outlet region B of the desulfurizer 7 toward the inlet region A (the liquid fuel tends to be relatively low in the latter stage than the inlet side of the desulfurizer 7. Therefore, the desulfurization catalyst is not heated more than necessary. As a result, while promoting the desulfurization reaction, it is possible to suppress a decrease in the life of the desulfurization catalyst, and the number of turns of the heater 8 in the outlet region B of the desulfurizer 7 is relatively reduced. It becomes possible to reduce power consumption. In FIG. 4, the length of the inlet region A in the axial direction of the desulfurizer 7 and the length of the outlet region B in the axial direction of the desulfurizer 7 are set to be substantially equal.

  Further, in the present embodiment, the configuration in which the axial direction of the desulfurizer 7 is installed so as to be in a state where the axial direction of the desulfurizer 7 is substantially vertical is illustrated, but as shown in FIG. You may install and use in the state which follows a horizontal direction, or the state which inclines. In this case, the thermometer 13 is disposed in the desulfurizer 7 and on the inlet side of the desulfurizer 7.

  The fuel cell stack 4 is not limited to a solid polymer fuel cell stack, and may be a solid oxide fuel cell stack or the like.

  Further, the reformer 5 is not limited to one that performs steam reforming, and may be one that undergoes partial oxidation reforming or autothermal reforming. The reforming method using the reformer 5 depends on the characteristics of liquid fuel such as kerosene, gasoline, naphtha, light oil, methanol, ethanol, DME (dimethyl ether), biofuel using biomass, and the like.

  Further, in the present embodiment, the outer periphery of the desulfurizer 7 has three regions of an inlet region A, an outlet region B, and a central region C (see FIGS. 2, 3, and 5), or an inlet region. A has two regions, A and an outlet region B (see FIG. 4). The outer periphery of the desulfurizer is divided into four or more regions, and the first region and the second region are separated from the liquid fuel inlet side. , The third region, the fourth region, and so on. Also in this case, the interval between adjacent windings in the heater 8 is set to be the smallest in the first region closest to the liquid fuel inlet side.

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 3 ... Desulfurization apparatus, 4 ... Fuel cell stack, 5 ... Reformer, 7 ... Desulfurizer, 8 ... Heater, 9 ... Power supply.

Claims (3)

A cylindrical desulfurizer that contains a desulfurization catalyst that removes sulfur from the liquid fuel to be supplied to a reformer that generates reformed gas containing hydrogen;
A heater for heating the liquid fuel in the desulfurizer;
A power source for energizing the heater,
The desulfurizer includes an inlet region on the inlet side of the liquid fuel in an outer periphery of the desulfurizer, an outlet region on the outlet side of the liquid fuel in an outer periphery of the desulfurizer, and the inlet in an outer periphery of the desulfurizer. A central region between the region and the exit region ;
The heater is wound around the outer periphery of the desulfurizer so as to be spiral,
The spacing between adjacent windings of the heater is
Set to be the smallest in the entrance region ,
Is set to be the largest in the central region,
The desulfurization apparatus , wherein the outlet region is set to be larger than the inlet region and smaller than the central region .   The liquid fuel inlet is provided on the lower end side of the desulfurizer so that the liquid fuel flows from the lower side to the upper side in the desulfurizer, and the liquid fuel outlet is the upper end of the desulfurizer. The desulfurization apparatus of Claim 1 provided in the side. A desulfurization apparatus according to claim 1 or 2 ,
A reformer that generates a reformed gas containing hydrogen using the liquid fuel from which sulfur content has been removed by the desulfurization apparatus;
A fuel cell system comprising: a fuel cell stack that generates electric power using the reformed gas generated by the reformer.

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