JP2009070626A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily control a flow rate of a liquid fuel introduced to a reformer and a flow rate of a liquid introduced to a heater by one pump. <P>SOLUTION: The fuel cell system 1 creates reformed gas with the reformer 8 by using the liquid fuel, and generates power with a PEFC stack by using the reformed gas. The fuel cell system 1 comprises a burner 9 for heating reformed catalyst of the reformer 8, a fuel circulation line L1 branched into a reformer line L12 for circulating the liquid fuel and introducing the liquid fuel to the reformer 8 and a burner line L12 for introducing the liquid fuel to the burner 9, and a pump 13 arranged at an upstream side of a branched point T of the reformer line L12 and the burner line L12 in the liquid fuel line L1 and press-feeding the liquid fuel to a downstream side. An orifice 43 is arranged in the burner line L12, and consequently, a flow rate of the liquid fuel introduced to the burner 9 is limited. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a fuel cell system that generates power using liquid fuel.

As a conventional fuel cell system, a reformer generates a reformed gas using a liquid fuel and generates electric power using the reformed gas in a fuel cell, and heats the reforming catalyst of the reformer. And a fuel distribution line through which liquid fuel introduced into the reformer and the heater flows are known (see, for example, Patent Document 1).
JP 2006-240952 A

  By the way, in recent fuel cell systems, in order to reduce the cost and simplify the fuel cell system, it is desired that liquid fuel can be supplied to the reformer and the heater with a single pump. However, in this case, in the fuel cell system as described above, when the flow rate of the liquid fuel introduced into the reformer and the heater is small as in the fuel cell system for home use, it is introduced into the reformer and the heater. There is a problem that it is difficult to easily control each flow rate of the liquid fuel.

  Accordingly, an object of the present invention is to provide a fuel cell system in which the flow rate of liquid fuel introduced into the reformer and the liquid flow rate introduced into the heater can be easily controlled with a single pump. .

  In order to solve the above problems, a fuel cell system according to the present invention is a fuel cell system that generates a reformed gas using a liquid fuel in a reformer and generates electric power using the reformed gas in a fuel cell. , Branching into a heater for heating the reforming catalyst of the reformer, a reformer line for introducing the liquid fuel into the reformer and a heater line for introducing the liquid fuel into the heater A fuel distribution line, and a pump provided upstream of the branch point between the reformer line and the heater line in the liquid fuel line, and pumping the liquid fuel downstream, and the heater line Further, it is characterized in that a diaphragm means is provided.

  In this fuel cell system, the flow rate of the liquid fuel introduced into the heater is limited by the throttle means provided in the heater line. Therefore, since the flow rate of the liquid fuel required by the heater is smaller than the flow rate of the liquid fuel required by the reformer, the flow rate of the liquid fuel is suitably controlled. Therefore, for example, the flow rate of the liquid fuel pumped by the pump is easily controlled so that the ratio between the flow rate of the liquid fuel introduced into the reformer and the flow rate of the liquid fuel introduced into the heater becomes a predetermined value. It becomes possible. That is, the flow rate of the liquid fuel introduced into the reformer and the liquid flow rate introduced into the heater can be easily controlled with a single pump. In addition, as a throttle means, the thing which made the orifice, the valve | bulb, and the pipe diameter small is mentioned, for example.

  Further, in the liquid fuel line, it is preferable that a check valve is provided upstream of the branch point and downstream of the pump so as to provide a flow resistance of the liquid fuel. In this case, the check valve can be a resistance member that provides resistance to the flow of the liquid fuel, and the liquid fuel introduced into the reformer and the heater is regulated, and each of these flow rates can be easily reduced at a low cost. It becomes possible to control.

  According to the present invention, the flow rate of the liquid fuel introduced into the reformer and the liquid flow rate introduced into the heater can be easily controlled with one pump.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or equivalent elements will be denoted by the same reference numerals, and redundant description will be omitted.

  FIG. 1 is a schematic configuration diagram showing a fuel cell system according to an embodiment of the present invention. The fuel cell system generates power using liquid fuel, and is employed, for example, as a household power supply source. Here, kerosene is used as the liquid fuel from the viewpoint that it is easily available and can be stored independently.

  As shown in FIG. 1, a fuel cell system 1 includes a desulfurizer 2, a fuel processing system (FPS) 3, a polymer electrolyte fuel cell (PEFC) stack (fuel cell) 4, an inverter 5, and a housing for housing these. 6 is provided.

  The desulfurizer 2 desulfurizes liquid fuel introduced from the outside. The desulfurizer 2 is provided with a heater (not shown), whereby the desulfurizer 2 heats the liquid fuel to, for example, 130 ° C. to 180 ° C. The FPS 3 is for reforming liquid fuel to generate a reformed gas, and includes a reformer 8 and a burner (heater) 9. The reformer 8 generates a reformed gas containing hydrogen by subjecting the desulfurized liquid fuel and steam (water) to a steam reforming reaction with a reforming catalyst. The burner 9 heats the reforming catalyst of the reformer 8 to supply a heat amount necessary for the steam reforming reaction.

  The PEFC stack 4 is configured by stacking a plurality of battery cells (not shown), and generates power using the reformed gas obtained by the FPS 3 to output a DC current. The battery cell has an anode, a cathode, and an electrolyte that is a solid polymer disposed between the anode and the cathode. By introducing the reformed gas into the anode and introducing air into the cathode, An electrochemical power generation reaction is performed in each battery cell.

  The inverter 5 converts the output DC current into AC current. The casing 6 accommodates the desulfurizer 2, the FPS 3, the PEFC stack 4, and the inverter 5 in a module.

  In addition, the fuel cell system 1 includes a liquid fuel line L1 that circulates the liquid fuel and introduces the liquid fuel into the reformer 8 and the burner 9. The liquid fuel line L1 is made of metallic piping, passes through the desulfurizer 2, and is connected to the reformer 8 and connected to the reformer line L11 for introducing liquid fuel into the reformer 8, and to the burner 9. Then, it is branched to a burner line L12 for introducing liquid fuel into the burner 9 via a branch point T. Near the reformer 8 in the reformer line L11, a water line L2 for introducing steam into the reformer 8 is connected.

  Next, the liquid fuel line L1 will be described in detail with reference to FIG. FIG. 2 is a schematic configuration diagram showing a liquid fuel line of the fuel cell system of FIG. As shown in FIG. 2, on the upstream side of the branch point T in the liquid fuel line L1, a pump 13, a flow meter 41, and a check valve 32 are provided in this order from the upstream side to the downstream side.

  The pump 13 pumps the liquid fuel to the downstream side of the liquid fuel line, and here, a constant flow pump is used. By adopting the constant flow pump in this way, the flow rate of the liquid fuel introduced into the reformer 8 and the burner 9 can be stabilized. A control device 42 is connected to the pump 13.

  The control device 42 includes, for example, a CPU, a ROM, a RAM, and the like. The control device 42 controls the flow of the liquid fuel pumped by the pump 13 by controlling the drive of the pump 13 based on the flow signal output from the flow meter 41.

  The flow meter 41 detects the flow rate of the passing liquid fuel and outputs a flow rate signal to the control device 42. The check valve 32 is of a spring type, and its valve body is biased by a spring in a direction opposite to the flow direction of the liquid fuel. That is, the check valve 32 is provided so as to provide resistance to the liquid fuel flow.

  A spillback line L3 for returning a part of the liquid fuel is provided from the downstream side of the pump 13 (here, between the flow meter 41 and the check valve 32) to the upstream side of the pump 13 in the liquid fuel line L1. It has been. The spillback line L3 includes a first spillback line L31 and a second spillback line L32 provided in parallel with the first spillback line L31. The safety valve 21 is provided in the first spillback line L31. The orifice 22 is provided in the second spillback line L32. That is, the spillback line L3 is provided with the safety valve 21 and the orifice 22 in parallel with each other with respect to the line L3.

  Here, the liquid fuel line L1 is branched into the reformer line L11 and the burner line L12 by the branch point T on the downstream side of the check valve 32 as described above. The burner line L12 is provided with a plurality (here, two) of orifices (throttle means) 43, 43. The orifice 43 has a tube diameter of, for example, 1 mm or less, and is 0.2 mm here.

  In the fuel cell system 1 configured as described above, first, for example, liquid fuel in an external fuel tank is introduced into the housing 6 by a pump (not shown). Subsequently, while the introduced liquid fuel is being pumped by the pump 13, the flow rate is controlled by the control device 42 based on the flow rate signal output from the flow meter 41. The pumped liquid fuel is regulated by the check valve 32, branched at the branch point T to the reformer line L11 and the burner line L12, and introduced into the reformer 8 and the burner 9, respectively. .

  Here, in the fuel cell system 1, as described above, the flow rate of the liquid fuel introduced into the burner 9 is limited by the orifices 43 and 43 provided in the burner line L12. Therefore, since the flow rate of the liquid fuel required by the burner 9 is smaller than the flow rate of the liquid fuel required by the reformer 8, the flow rate of the liquid fuel is suitably controlled. As a result, the drive control of the pump 13 by the controller 42 can be facilitated. For example, the ratio between the flow rate of the liquid fuel introduced into the reformer 8 and the flow rate of the liquid fuel introduced into the burner 9 is a predetermined value. Thus, the flow rate of the liquid fuel pumped by the pump 13 can be easily controlled. That is, the flow rate of the liquid fuel introduced into the reformer 8 and the liquid flow rate introduced into the burner 9 can be easily controlled by one pump 13.

  Further, as described above, since the plurality of orifices 43, 43 are provided in the burner line L12, the pressure fluctuation of the liquid fuel introduced into the burner 9 can be suppressed.

  Further, in the liquid fuel line L1, a check valve 32 is provided on the upstream side of the branch point T and the downstream side of the pump 13 so as to provide resistance to the flow of the liquid fuel. Therefore, the check valve 32 can be a resistance member that provides resistance to the flow of the liquid fuel, the liquid fuel introduced into the reformer 8 and the burner 9 is regulated, and these flow rates can be easily reduced at low cost. It becomes possible to control to. Therefore, the flow rate of the liquid fuel introduced into the reformer 8 and the liquid flow rate introduced into the burner 9 can be more easily controlled by one pump 13.

  Further, as described above, the spillback line L3 for returning a part of the liquid fuel from the downstream side of the pump 13 to the upstream side of the pump 13 is provided, and the safety valve 21 and the orifice 22 are provided in the spillback line L3. L3 are provided in parallel with each other. Therefore, a part of the liquid fuel pumped by the pump 13 is returned to the upstream side of the pump 13 through the safety valve 21 and also returned to the upstream side of the pump 13 through the orifice 22, so that it was pumped by the pump 13. The pressure fluctuation and flow fluctuation of the liquid fuel can be suppressed.

  By the way, when the fuel cell system is for home use as in the present embodiment, the flow rate of the liquid fuel introduced into the reformer 8 and the burner 9 is extremely small (for example, 2 cc / min). The allowable flow rate fluctuation range is extremely narrow (for example, ± 5%). Therefore, a pipe having a very small diameter is particularly desired for the liquid fuel line L1 of the household fuel cell system 1.

  From the viewpoint of easily forming a pipe having an extremely small diameter, the pipe is preferably made of a resin, but there is a concern about the elution of the resin component into the liquid fuel. On the other hand, when a metallic pipe is used for the liquid fuel line L1, it is possible to prevent the pipe components from eluting into the liquid fuel as compared with a resin pipe. However, it is practically difficult to control a very small flow rate by adjusting the metallic pipe diameter. Therefore, in the conventional fuel cell system, expensive high-precision equipment and a complicated flow control system are required.

  On the other hand, in the fuel cell system 1, as described above, the flow rate of the liquid fuel introduced into the reformer 8 and the liquid flow rate introduced into the burner 9 can be easily controlled by one pump 13. . Therefore, even if the diameter of the pipe is extremely small, the cost of the fuel cell system can be reduced and the flow rate control system can be simplified. That is, it can be said that the fuel cell system 1 is particularly innovative in the field of household fuel cell systems.

  In the present embodiment, the orifice 43 is provided as the throttling means. However, instead of this, for example, a valve (for example, a needle valve) may be provided, or a part of the tube diameter is reduced (diameter). In some cases, a small pipe) is provided.

  When the orifice 43 is used as the throttle means as in the present embodiment, the configuration of the piping can be simplified and the cost can be reduced. Further, in this case, productivity and merchantability can be improved. Further, by superposing a plurality of orifices having different diameters, the flow rate can be controlled as desired, and the pressure fluctuation can be easily reduced.

  On the other hand, when a valve is used as the throttle means, for example, when foreign matter such as dust is clogged in the pipe, the foreign matter can be easily removed, and maintainability can be improved. In this case, the flow rate can be controlled as desired by adjusting the opening of the valve. In the case where a part of the pipe diameter is reduced, the flow rate can be controlled, and the pressure fluctuation can be reduced by the pipe length.

  The preferred embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment.

  For example, in the above embodiment, kerosene is used as the liquid fuel. However, gasoline, naphtha, light oil, methanol, ethanol, DME (dimethyl ether), and biofuel using biomass may be used. In this case, the desulfurizer (desulfurization method) and the reformer (reformation method) are adapted to the characteristics of the liquid fuel used.

  In the above embodiment, the liquid fuel is steam reformed in the reformer 8, but autothermal reforming (ATR) may be performed. In short, a heater is used to heat the reforming catalyst of the reformer. (Heater line) may be provided. Moreover, in the said embodiment, although it was set as the fuel cell system 1 provided with the PEFC stack 4, it is good also as a fuel cell system provided with the solid oxide fuel cell (SOFC) stack.

  Moreover, in the said embodiment, although the constant flow pump was employ | adopted as the pump 13, you may employ | adopt various pumps other than constant flow pumps, such as an electromagnetic pump, for example. If a constant flow pump is employed as the pump 13 as in the above embodiment, the spillback line L3 may be unnecessary depending on circumstances. Moreover, in the said embodiment, although the two orifices 43 and 43 were provided in the burner line L12, you may provide one or three or more orifices. When a plurality of orifices are provided, the pressure fluctuation of the liquid fuel introduced into the burner 9 can be suitably suppressed.

1 is a schematic configuration diagram showing a fuel cell system according to an embodiment of the present invention. It is a schematic block diagram which shows the liquid fuel line of the fuel cell system shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 2 ... Desulfurizer, 4 ... PEFC stack (fuel cell), 8 ... Reformer, 9 ... Burner (heater), 13 ... Pump, 43 ... Orifice (throttle means), 32 ... Non-return Valve, L1 ... Liquid fuel line, L11 ... Reformer line, L ... 12 burner line (heater line), T ... Branch point.

Claims (2)

A fuel cell system that generates a reformed gas using liquid fuel in a reformer and generates electric power using the reformed gas in a fuel cell,
A heater for heating the reforming catalyst of the reformer;
A fuel distribution line that is branched into a reformer line that introduces the liquid fuel into the reformer and a heater line that introduces the liquid fuel into the heater;
A pump provided upstream of a branch point between the reformer line and the heater line in the liquid fuel line, and pumping the liquid fuel downstream;
A fuel cell system, wherein the heater line is provided with a throttle means.   2. The fuel according to claim 1, wherein a check valve is provided on the upstream side of the branch point and the downstream side of the pump in the liquid fuel line so as to provide a resistance for the flow of the liquid fuel. Battery system.

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