JP2011194339A - Liquid cyclone filter apparatus and direct methanol type fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuel cell system which can suitably remove impurity in liquid that is mixed with air bubbles.SOLUTION: A liquid cyclone filter apparatus in the fuel cell system has a liquid cyclone filter 55 and a liquid supply nozzle 58. The liquid cyclone filter 55 is installed in a dilution tank 35 which can store a dilution solution A and is equipped with a cylinder part 53 and an injecting pipe part 54 which is provided at an injection port 60 of the cylinder part 53. The liquid supply nozzle 58 is equipped with a housing 57 which is disposed at the injecting pipe part 54, is dipped in the dilution solution A in the dilution tank 35 and covers a nozzle part and a circumference of the nozzle part and at which a suction port 64 is formed. As for the liquid supply nozzle 58, a circulating solution B from the injecting pipe part 54 is ejected from a nozzle part. Thereby the dilution solution A in the dilution tank 35 is sucked from the suction port 64 and is mixed with the solution ejected from the nozzle part. A mixed solution is guided to the injection port 60, and as for the liquid cyclone filter 55, the mixed solution is injected from the injection port 60 into the cylinder part 53 and is made to swirl around an axis of the cylinder part 53 to carry out centrifugal separation of impurities in the mixed solution.

Description

  The present invention relates to a liquid cyclone filter device that removes impurities in a liquid, and a direct methanol fuel cell system including the liquid cyclone filter device in a dilution tank.

  In a direct methanol fuel cell system, a diluted solution of methanol in water is used as fuel, and this fuel is pressurized by a pump and circulated between a cell stack (fuel cell) and a dilution tank to obtain electric power. At this time, there is a phenomenon that the circulating solution of fuel recirculated from the cell stack contains a small amount of impurities (sludge), and the impurities accumulate in the diluted solution in the dilution tank or float in the solution. If impurities are mixed in the diluted solution, the detection capability of the methanol concentration sensor that is installed in the dilution tank and detects the methanol concentration may be reduced.

  A liquid cyclone filter is known as an existing technique for removing impurities in a liquid (see Patent Document 1). As shown in FIG. 8, the liquid cyclone filter 1 injects a liquid 4 from an injection pipe portion 3 into a cylindrical cylinder portion 2 having a reduced diameter at the lower half, and uses this liquid flow to make a cylinder 2 The liquid 4 is swirled inside. The centrifugal force generated in the swirling flow causes the impurities 5 in the liquid 4 to be centrifuged, the impurities 5 are discharged from the lower part of the cylinder part 2, and the clarified liquid 6 from which the impurities 5 have been removed is removed from the upper center of the cylinder part 2. Spilled from.

Japanese Patent Laid-Open No. 10-137520

Kariyazaki, Kagawa “Void distribution and liquid flow velocity distribution of a bubble jet formed by a single nozzle”, Fukuoka University Engineering Bulletin, September 2006, No. 77

  However, as shown in FIG. 9, the circulating solution 7 refluxed from the cell stack of the direct methanol fuel cell system to the dilution tank contains a large amount of bubbles 8, and this circulating solution 7 is contained in the liquid cyclone filter 1 shown in FIG. In the case of processing with, for example, about 50% or more of the injection pipe portion 3 may be occupied by the bubbles 8. For this reason, even if an attempt is made to remove impurities in the circulating solution 7 mixed with such bubbles 8 using the liquid cyclone filter 1, a sufficient amount of liquid cannot be supplied to the liquid cyclone filter 1. Impurities may not be removed well.

  An object of the present invention is to provide a liquid cyclone filter device and a direct methanol fuel cell system that can suitably remove impurities in a liquid mixed with bubbles.

  A hydrocyclone filter device according to the present invention includes a cylinder portion that is installed in a tank capable of storing liquid and has a diameter that is substantially reduced in a lower half portion, and an injection pipe portion that is provided at an inlet at the top of the cylinder portion. A liquid cyclone filter provided, a supply unit provided in the injection pipe unit and immersed in the liquid in the tank, and a nozzle unit and a housing unit that covers the periphery of the nozzle unit and has a suction port formed therein. A liquid nozzle, and the liquid supply nozzle discharges the liquid from the injection pipe portion from the nozzle portion, thereby sucking the liquid in the tank from the suction port and discharging liquid from the nozzle portion. The mixed liquid is guided to the inlet of the cylinder part, and the liquid cyclone filter injects the mixed liquid into the cylinder part from the inlet, And the body to pivot about the axis of the cylinder portion, is characterized in that an impurity of the mixed liquid configured to centrifugation.

  In the direct methanol fuel cell system according to the present invention, the liquid cyclone filter device according to the present invention is installed in a dilution tank as a tank, and the liquid is a fuel in which methanol as a solute is dissolved in water as a solvent. It is characterized by being.

  According to the liquid cyclone filter device and the direct methanol fuel cell system according to the present invention, even when bubbles are mixed in the liquid (fuel) from the injection pipe portion of the liquid cyclone filter, the liquid cyclone filter device and the direct methanol fuel cell system are arranged in the injection pipe portion. The liquid supply nozzle provided sucks the liquid in the tank (dilution tank) and mixes it with the liquid in which bubbles are mixed, and guides this mixed liquid to the inlet of the liquid cyclone filter. As a result, a sufficient amount of liquid is secured in the cylinder portion of the liquid cyclone filter, so that impurities in the liquid can be suitably removed by centrifugation even in a liquid mixed with bubbles.

1 is a left side view showing a handle-type electric wheelchair vehicle equipped with a direct methanol fuel cell system to which an embodiment of a hydrocyclone filter device according to the present invention is applied. The system block diagram which shows the direct methanol type fuel cell system mounted in the steering wheel type electric wheelchair vehicle of FIG. The schematic block diagram which shows the hydrocyclone filter apparatus installed in the dilution tank of FIG. 2 with a dilution tank. Explanatory drawing which shows the flow of the liquid in the liquid cyclone filter of FIG. FIG. 4 is a cross-sectional view of the liquid supply nozzle of FIG. 3, wherein (A) shows a liquid supply state according to Bernoulli's theorem and (B) shows a liquid supply state by bubble wake. The schematic block diagram which shows other embodiment of the hydrocyclone filter apparatus which concerns on this invention. The schematic block diagram which shows other embodiment of the hydrocyclone filter apparatus which concerns on this invention. The schematic block diagram which shows the conventional liquid cyclone filter. FIG. 9 is a schematic cross-sectional view of an injection pipe portion showing a state of a liquid flowing in the injection pipe portion of the liquid cyclone filter of FIG. 8.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  A handle type electric wheelchair vehicle 10 as an electric vehicle equipped with a fuel cell shown in FIG. 1 is provided with a pair of left and right front wheels 11 at the front end of the vehicle and a pair of left and right rear wheels 12 at the rear end of the vehicle. A footrest floor 13 with a low floor is installed at the front, and a driving seat 14 is installed at the rear of the vehicle. A power unit 16 covered with a vehicle body cover 15 is arranged below the driving seat 14.

  The footrest floor 13 shown in FIG. 1 is formed in a flat shape so that an occupant seated on the driving seat 14 can place his / her feet together. The driving seat 14 is configured as a chair with a backrest.

  The power unit 16 is configured as a hybrid type having a fuel cell system 18 (FIG. 2) and a secondary battery (not shown). The power unit 16 supplies the electric power (electric energy) generated in the fuel cell system 18 and the electric power from the secondary battery that stores the electric power to the drive unit 20 having an electric motor to supply the rear wheel 12. Drive.

  The vehicle body frame 21 of the handle type electric wheelchair vehicle 10 described above is a platform-type vehicle body frame, and includes a main frame 22 arranged in a pair of left and right in the vehicle width direction, and a plurality of beam members (between the main frames 22). (Not shown). Further, a floor member (not shown) for the footrest floor 13 is installed between the pair of main frames 22 on the center front side of the main frame 22. Further, a seat pipe 25 formed in a curved shape is straddled at the rear portion of the main frame 22, and a seat post 26 that supports the operation seat 14 is attached to the center top portion of the seat pipe 25.

  The front wheel 11 is pivotally supported at the front end portion of the vehicle body frame 21 thus configured by a steering mechanism including a front wheel suspension device (not shown) and a steering post 27 so as to be steerable left and right. The steering post 27 is erected upward in the leg shield 28 that covers the feet of the occupant, and a steering handle 29 is integrally provided at the upper end portion thereof. The front wheel 11 is steered left and right by a steering handle 29 via a steering post 27.

  A front end portion of the drive unit 20 is pivotally attached to a pivot bracket 30 provided at the rear end portion of the vehicle body frame 21 so as to be swingable in the vertical direction. The drive unit 20 is seated on the seat of the vehicle body frame 21 by a cushion unit 31. The pipe 25 is elastically supported. The drive unit 20 includes an electric motor and a gear case (both not shown).

  Now, the power unit 16 disposed below the operation seat 14 has a fuel cell system 18, and this fuel cell system 18 is a direct methanol fuel cell system. This direct methanol fuel cell system is a fuel cell system that generates electric energy by directly feeding methanol into the negative electrode of a fuel cell (cell stack) as fuel.

  This direct methanol fuel cell system will be described with reference to FIG. By supplying fuel to the negative electrode of the cell stack 32 and air (oxygen) to the positive electrode, an electrochemical reaction is performed in the cell stack 32 to generate power, while carbon dioxide is supplied to the negative electrode and water is supplied to the positive electrode. Arise.

  As for the fuel system, the fuel (for example, 54% methanol aqueous solution) stored in the fuel tank 33 is conveyed to the dilution tank 35 by the fuel pump 34, and the optimal concentration (for example, 3% methanol aqueous solution) is contained in the dilution tank 35 with water. Diluted to The diluted fuel is sent to the negative electrode of the cell stack 32 by the circulation pump 37 after impurities are removed by the liquid cyclone filter device 52 and the fuel filter 36 described later.

  Since the output characteristics of the cell stack 32 are greatly influenced by the fuel concentration, the fuel concentration (methanol concentration) in the dilution tank 35 is monitored by the methanol concentration sensor 38. Based on the concentration information from the methanol concentration sensor 38, the driving of the water pump 39 and the fuel pump 34 is controlled, so that water as a solvent from the water tank 41 and fuel as a solute from the fuel tank 33 into the dilution tank 35, respectively. Then, the fuel concentration in the dilution tank 35 is adjusted to an optimum concentration.

  In the case of a direct methanol fuel cell, since the fuel is liquid, the fuel itself has a cooling function for the cell stack 32. Therefore, unreacted fuel discharged from the negative electrode outlet of the cell stack 32, carbon dioxide generated by the electrochemical reaction, and the like are introduced into the fuel cooling system heat exchanger 42, and the cooling fan 43 is supplied to the fuel cooling system heat exchanger 42. The unreacted fuel and the like are cooled by guiding cooling air from the air, and thereby the temperature of the fuel at the negative electrode outlet is lowered to the optimum temperature, and the temperature of the cell stack 32 is controlled. Here, the fuel cooling system heat exchanger 42 may be installed not only after passing through the cell stack 32 but also in fuel piping before passing through the cell stack 32.

  The unreacted fuel, carbon dioxide and the like cooled by the fuel cooling system heat exchanger 42 are guided to the dilution tank 35, the unreacted fuel is reused as fuel, and the carbon dioxide passes through the carbon dioxide pipe 44 to the water tank 41. To be introduced. The carbon dioxide pipe 44 is provided with a check valve 45 to prevent a back flow toward the dilution tank 35 side.

  As for the air system, impurities in the air are removed by the air filter 46, and air (oxygen) is pumped to the positive electrode of the cell stack 32 by the compressor 47. From the positive electrode outlet of the cell stack 32, unreacted air and water generated by the electrochemical reaction are discharged.

  Here, since the optimum operating temperature of the cell stack 32 is relatively high, such as about 70 ° C. to 80 ° C., most of the generated water is in the state of water vapor. In order to dilute the fuel in the dilution tank 35, the generated water needs to be stored in the water tank 41 in a water state. Therefore, unreacted air and water vapor at the positive electrode outlet of the cell stack 32 are introduced into the exhaust cooling system heat exchanger 48, and the cooling air is guided from the cooling fan 49 to the exhaust cooling system heat exchanger 48, thereby Air and water vapor are cooled and water vapor is condensed to increase the recovery rate of product water.

  The unreacted air and water vapor cooled by the exhaust cooling system heat exchanger 48 and the carbon dioxide discharged to the water tank 41 through the carbon dioxide pipe 44 are mixed in the water tank 41, and the exhaust gas purifier 50 (for example, After the harmful components are removed and purified by the catalyst), they are discharged into the atmosphere through the exhaust gas discharge pipe 51.

  As described above, the fuel (also referred to as dilution solution A) diluted as liquid in the dilution tank 35 circulates between the cell stack 32 and the dilution tank 35 by the operation of the circulation pump 37. The dilute solution (also referred to as circulating solution B) refluxed from the cell stack 32 to the diluting tank 35 contains impurities (sludge) in a small amount and also contains a large amount of bubbles C (for example, carbon dioxide bubbles). In order to remove impurities in the circulating solution B mixed with the bubbles C, a liquid cyclone filter device 52 is installed in the dilution tank 35 together with the fuel filter 36.

  As shown in FIG. 3, the hydrocyclone filter device 52 includes a liquid cyclone filter 55 having a cylinder portion 53 and an injection pipe portion 54, a liquid supply nozzle 58 having a nozzle portion 56 (FIG. 5) and a housing 57. It is comprised.

  The liquid cyclone filter 55 is installed in the dilution tank 35 in which the diluted solution A can be stored. The cylinder portion 53 is configured by contracting a substantially lower half portion into a conical shape, and a liquid swirl chamber 59 is provided therein as shown in FIGS. 3 and 4. An injection port 60 is formed in the upper portion of the cylinder portion 53, and an injection pipe portion 54 is connected to the injection port 60 so as to communicate therewith.

  Further, a sludge storage part 61 or a discharge valve (not shown) is provided at the lowest position of the cylinder part 53. Impurities separated as described later in the cylinder part 53 are discarded through the sludge storage part 61 or the discharge valve.

  Further, at the uppermost central position of the cylinder portion 53, there is provided an outflow portion 62 for allowing the diluted fuel (also referred to as a clarified solution D) after the impurities are removed and the bubbles C to flow out as described later. In addition, the code | symbol 63 in FIG. 3 is the discharge drum for accumulating and discharging the bubble C. FIG.

  The liquid supply nozzle 58 is disposed in the injection pipe portion 54 of the liquid cyclone filter 55 and is immersed in the diluted solution A in the dilution tank 35. Note that reference numeral 65 in FIG. 3 indicates the liquid level of the diluted solution A. As shown in FIG. 5, the nozzle portion 56 is connected to the injection pipe portion 54 and discharges the pressurized circulating solution B from the injection pipe portion 54. In addition, the housing 57 covers the periphery of the nozzle portion 56 and is connected to the injection pipe portion 54, and a suction port 64 directed to the tip portion of the nozzle portion 56 is formed.

  In general, as shown in FIG. 5A, when a pressurized liquid is discharged from the nozzle portion 56 of the liquid supply nozzle 58, a negative pressure P is generated around the discharged liquid according to Bernoulli's theorem. Thereby, the liquid is sucked from the suction port 64 of the housing 57, and the liquid discharged from the nozzle portion 56 and the liquid sucked from the suction port 64 can be mixed.

  By the way, it is known that when a bubble moves in a liquid, a spiral wake (backward turbulent flow) accompanies the bubble. The amount of liquid entrained by the wake is about 0.3 to 1 times the volume of the bubble, and the moving speed of the liquid by the wake is almost equal to the moving speed of the bubbles (Non-Patent Document 1).

  As shown in FIG. 5B, when pressurized air is discharged (spouted) as fine bubbles C from the nozzle portion 56 of the liquid supply nozzle 58 having the same structure as that shown in FIG. Wake E occurs. Since the wake E moves while sucking the surrounding liquid from the suction port 64 of the housing 57 as the bubble C moves, a liquid flow is generated behind the nozzle portion 56. If the liquid flow exists in this manner, the liquid is more actively sucked from the suction port 64 according to Bernoulli's theorem, so that the fluid mixture of fine bubbles and liquid flows downstream of the nozzle portion 56.

  Therefore, as shown in FIG. 5A, in the liquid supply nozzle 58 of the present embodiment, when the circulating solution B mixed with the bubbles C from the injection pipe portion 54 is discharged from the nozzle portion 56, the nozzle portion 56 The diluted solution A in the dilution tank 35 is sucked from the suction port 64 of the housing 57 by the action of the negative pressure P generated at the rear of this, and the sucked diluted solution A is mixed with the bubbles C discharged from the nozzle portion 56. Mix with circulating solution B. Then, the mixed solution F is guided to the injection port 60 of the cylinder portion 53 of the liquid cyclone filter 55 through the injection pipe portion 54.

  In the liquid cyclone filter 55, as shown in FIGS. 3 and 4, the mixed solution F is injected from the inlet 60 into the liquid swirl chamber 59 of the cylinder portion 53, and this mixed solution F is rotated around the axis O of the cylinder portion 53. The liquid cyclone chamber 59 descends while swirling. Here, the angular velocity ω of the rotating fluid flow in contact with the inner wall of the inner diameter r of the cylinder portion 53 generated by the fluid flow having the average flow velocity v0 is represented by ω = v0 / r. Therefore, the angular velocity ω of the rotating liquid flow increases as the radius r decreases, and the centrifugal force acting on the liquid increases.

  Impurities contained in the mixed solution F are centrifuged toward the inner wall surface of the cylinder portion 53 by the action of the centrifugal force, and are discharged to the outside from the sludge storage portion 61 and the like at the lower end portion of the cylinder portion 53. Further, the clarified solution D and the bubbles C from which the impurities have been separated flow out from the outflow portion 62 provided at the rotation center of the cylinder portion 53, the clarified solution D is refluxed into the dilution tank 35, and the bubbles C are discharged from the discharge drum 63. It is discharged through.

  With the configuration as described above, according to the present embodiment, the following effects (1) to (4) are achieved.

  (1) Even when bubbles C are mixed in the circulating solution B from the injection pipe portion 54 of the liquid cyclone filter 55, the liquid supply nozzle 58 disposed in the injection pipe portion 54 is provided in the dilution tank 35. The diluted solution A is sucked and mixed with the circulating solution B in which bubbles C are mixed, and the mixed solution F is guided to the inlet 60 of the hydrocyclone filter 55. As a result, a sufficient amount of liquid is ensured in the cylinder portion 53 of the liquid cyclone filter 55, so that even in the circulating solution B mixed with the bubbles C, impurities in the circulating solution B are centrifuged by the liquid cyclone filter 55. Can be suitably removed. For this reason, since the impurities in the diluted solution A in the dilution tank 35 mixed with the circulating solution B as the clarified solution D can be suppressed, the detection capability of the methanol concentration sensor 38 installed in the diluted tank 35 is enhanced. The accuracy can be maintained.

  (2) Since the liquid cyclone filter 55 and the liquid supply nozzle 58 of the liquid cyclone filter device 52 are installed in the dilution tank 35, the liquid cyclone filter 55 and the liquid supply are compared with the case where they are installed outside the dilution tank 35. The installation space for the nozzle 58 and the space for extending and routing the piping are not required. Further, since the liquid supply nozzle 58 is immersed in the diluted solution A in the dilution tank 35 and the diluted solution A is directly sucked from the suction port 64 of the liquid supply nozzle 58, piping is unnecessary. As a result, the fuel cell system 18 (direct methanol fuel cell system) can be downsized.

  (3) The liquid supply nozzle 58 uses the negative pressure P generated in the circulating solution B discharged from the nozzle portion 56 to suck in the diluted solution A in the dilution tank 35 from the suction port 64, and the circulating solution mixed with the bubbles C. Since B and the diluting solution A are mixed, a dedicated power is not required for this gas-liquid mixing. Furthermore, a dedicated liquid for mixing with the circulating solution B mixed with the bubbles C is not necessary, and the cost of the fuel cell system 18 (direct methanol fuel cell system) can be suppressed.

  (4) The liquid cyclone filter 55 centrifuges impurities in the circulating solution B when the circulating solution B injected from the injection port 60 rotates in the cylinder portion 53, so that impurities can be removed without using dedicated power. It can be suitably removed.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this invention is not limited to this.

  For example, the diluting solution A in the diluting tank 35 is a solution in which fuel as a solute (for example, a 54% aqueous solution of methanol) is dissolved in water as a solvent. As shown in FIG. 6, a replenishing solute is introduced. The solute introducing pipe 66 and the solvent introducing pipe 67 for introducing the replenishing solvent may be connected to the upstream side portion of the liquid supply nozzle 58 in the injection pipe portion 54 of the liquid cyclone filter 55. Alternatively, as shown in FIG. 7, the introduction port 66 </ b> A of the solute introduction pipe 66 and the introduction port 67 of the solvent introduction pipe 67 may be disposed near the suction port 64 of the liquid supply nozzle 58. With this configuration, the replenishing solute and the solvent are circulated into the circulating solution B from the injection pipe portion 54 and the diluted solution A in the dilution tank 35 by a swirling flow in the cylinder portion 53 of the liquid cyclone filter 55. Stir and mix efficiently.

  In the above-described embodiment, the case of removing impurities in the fuel in the direct methanol fuel cell system 18 has been described. However, the liquid cyclone filter of the present invention can be used for removing impurities in oil or cooling water for vehicles or general-purpose engines. A device can also be applied.

18 Fuel cell system (Direct methanol fuel cell system)
35 Dilution tank 52 Hydrocyclone filter device 53 Cylinder part 54 Injection pipe part 55 Liquid cyclone filter 56 Nozzle part 57 Housing 58 Liquid supply nozzle 60 Inlet 64 Suction inlet 66 Solute introduction pipe 67 Solvent introduction pipes 66A, 67A Inlet O cylinder part Axis of

Claims (4)

A liquid cyclone filter that is installed in a tank capable of storing liquid and has a cylinder portion whose diameter is reduced substantially in the lower half, and an injection pipe portion provided in an injection port at the upper portion of the cylinder portion;
A liquid supply nozzle provided with a housing portion that is disposed in the injection pipe portion and is immersed in the liquid in the tank, covers the periphery of the nozzle portion, and is formed with a suction port;
The liquid supply nozzle causes the liquid from the injection pipe portion to be discharged from the nozzle portion, thereby sucking the liquid in the tank from the suction port and mixing it with the discharge liquid from the nozzle portion. Led to the inlet of the cylinder part,
The liquid cyclone filter is configured to inject the mixed liquid into the cylinder part from the injection port, rotate the mixed liquid around the axis of the cylinder part, and centrifuge impurities in the mixed liquid. A liquid cyclone filter device.   The liquid in the tank is a solution in which a solute is dissolved in a solvent, and a solute introduction part for introducing the solute and a solvent introduction part for introducing the solvent are liquid supply nozzles in an injection pipe part of a liquid cyclone filter. The hydrocyclone filter device according to claim 1, wherein the hydrocyclone filter device is connected to an upstream side of the first cyclone filter.   The liquid in the tank is a solution in which a solute is dissolved in a solvent, and an inlet of the solute introduction part for introducing the solute and an introduction port of the solvent introduction part for introducing the solvent are sucked into the liquid supply nozzle. The liquid cyclone filter device according to claim 1, wherein the liquid cyclone filter device is arranged near the mouth. The hydrocyclone filter device according to any one of claims 1 to 3 is installed in a dilution tank as a tank,
A direct methanol fuel cell system, wherein the liquid is a fuel in which methanol as a solute is dissolved in water as a solvent.

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