CN113644296B - Fuel cell anode drainage device and drainage system - Google Patents

Abstract

The invention discloses a fuel cell anode drainage device and a drainage system, which integrate condensation of vapor in hydrogen and drainage of liquid water through the drainage and air-blocking characteristics of a hollow fiber membrane, control the dew point of anode hydrogen by using low-temperature cooling water, play a role in quick and efficient drainage, and have the advantages of compact structure, simplicity and reliability. The invention solves the problem of anode drainage of the alkaline membrane fuel cell, and has application prospect in the aspect of promoting the engineering application of the alkaline membrane fuel cell stack.

Description

A fuel cell anode drainage device and drainage system

technical field

The invention relates to the technical field of fuel cells, in particular to a fuel cell anode drainage device and a drainage system, and in particular to fuel cell anode water management.

Background technique

Different from the proton exchange membrane fuel cell, the alkaline anion exchange membrane fuel cell generates water at the anode, and the product water needs to be swept or carried out from the diffusion layer by hydrogen, which requires the hydrogen to have a large circulation ratio and the water content of the inlet and outlet hydrogen. The difference is large, that is, the anode has a strong drainage capacity.

The existing anode water management is usually developed for PEMFC, and the liquid water content of the PEMFC anode itself is small. Usually, a hydrogen circulation pump or an ejector is used to circulate the hydrogen in the anode, and a centrifugal separator is added to the hydrogen circulation pipeline. The water separator or gravity water separator discharges the water and has a good liquid water separation effect. However, for alkaline membrane fuel cells, since the anode produces water, the amount of water produced is much larger than that of PEMFC anodes, especially the anodes of alkaline membrane fuel cells need to control the relative humidity of the hydrogen inlet and outlet of the stack anode to make the anode moisture quickly. However, the traditional traditional centrifugal water separator has no condensation effect, and the water separation effect is not enough to meet the drainage needs. If the excess water in the hydrogen circulation pipeline cannot be discharged in time, the excess water will cover the catalyst during the electrochemical reaction, so that the hydrogen cannot be fully transferred to the catalyst surface.

SUMMARY OF THE INVENTION

In order to solve the above technical problems, the present invention provides a fuel cell anode drainage device and a drainage system. The invention mainly utilizes the drainage and gas barrier properties and pressure difference of the microporous fiber membrane, and integrates the condensation of hydrogen and the drainage of liquid water into one device, thereby achieving the effect of fast and efficient drainage, and at the same time, it has a compact, simple and reliable structure. advantage.

The technical scheme adopted in the present invention is as follows:

In one aspect, the present invention provides an anode drainage device of an alkaline anion exchange membrane fuel cell, the drainage device comprises a drainer arranged between the hydrogen outlet and the hydrogen inlet of the fuel cell; the drainer is provided with a water circulation branch;

The drainer is sequentially provided with a hydrogen chamber I, a sealant I, a water chamber, a sealant II, and a hydrogen chamber II along the hydrogen flow direction. The hydrogen chamber I and the hydrogen chamber II are connected by a hollow fiber bundle, and the hollow fiber bundle is in a wet state. The lower part has the function of water permeability and gas resistance when there is a pressure difference. The two ends of the hollow fiber bundle pass through the sealant and are open pipes; the sealant I isolates the hydrogen cavity I and the water cavity; the sealant II separates the hydrogen cavity II and the water cavity. Isolation; the hydrogen chamber I is provided with a hydrogen inlet, which is communicated with the hydrogen outlet of the fuel cell; the hydrogen chamber II is provided with a hydrogen outlet, and the hydrogen outlet is communicated with the hydrogen inlet of the fuel cell; the water chamber has two interfaces , are the inlet and outlet of the circulating water, respectively.

Based on the above solution, preferably, the components of the hollow fiber bundle are at least one of polyethersulfone and polycellulose acetate; the tube wall of the hollow fiber bundle contains micropores, and the pore size is less than 1 μm to have capillary force; In the wet state, the fiber tube wall will not leak under the pressure difference exceeding the hydrogen pressure.

Based on the above solution, preferably, the drainage device further includes a return pump; the return pump is located between the drain and the hydrogen inlet of the fuel cell, and is used for pressurizing the drained hydrogen.

Based on the above solution, preferably, the reflux pump is a hydrogen circulation pump or an ejector, and the hydrogen rich in water vapor at the anode outlet of the stack enters the reflux pump after being condensed and drained by the drain, and then enters the stack to achieve high hydrogen utilization. Rate.

When the above-mentioned drainage device is used, the pressure of the water in the water chamber is lower than the pressure of the gas in the hollow fiber bundle, the temperature of the water in the water chamber is lower than the temperature of the gas in the hollow fiber bundle, and the hydrogen is transmitted from the hydrogen chamber I to the hydrogen through the hollow fiber bundle. In the process of cavity II, the gaseous water in the hydrogen is condensed into liquid water under the temperature difference of the circulating water, and the condensed liquid water and the liquid water carried by the hydrogen are discharged into the water cavity through the outer wall of the hollow fiber bundle under the action of the pressure difference, and then through the circulation The water outlet is drained; the drain is combined with the fuel cell stack to form the anode drain system of the fuel cell.

When the above-mentioned drainage device is used, the water volume of the condensed water can be controlled according to the different designed temperature differences between the saturated vapor pressure at different temperatures and the gas temperature.

In another aspect, the present invention provides an anode drainage system of an alkaline anion exchange membrane fuel cell, the drainage system comprising the above-mentioned fuel cell anode drainage device.

Specifically, the fuel cell stack, the drain, and the return pump are connected in sequence, and the circulating cooling water is connected to the water cavity port of the drain to form an anode drainage system; the temperature and air pressure of the stack, the return flow of the return pump, and the water circulation support are controlled. The temperature and pressure of the water in the road can control the water content and gas flow of the hydrogen at the inlet of the stack, thereby controlling the water content of the anode.

Beneficial effects of the present invention:

1. The device of the present invention integrates the discharge of liquid water and the control of the relative humidity of hydrogen, and has the advantages of good drainage effect, compact structure, simplicity and reliability.

2. The device of the present invention has timely and sufficient drainage, taking into account the condensation of saturated steam and the discharge of liquid water; the influence on the electrochemical reaction that the excess water in the hydrogen circulation pipeline cannot be discharged in time is avoided.

Description of drawings

In order to illustrate the embodiments of the present invention or the technical solutions in the prior art more clearly, the following briefly introduces the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are some embodiments of the present invention, and for those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

Figure 1 is a schematic diagram of the structure of the anode drainage system.

In the figure, 1-fuel cell stack; 2-fuel cell hydrogen outlet; 3-hydrogen chamber I hydrogen inlet; 4-hydrogen chamber I; 5-water chamber; 6-hydrogen chamber II; 7-hollow fiber bundle; 8- Circulating water outlet; 9-circulating water inlet; 10-hydrogen chamber II hydrogen inlet; 11-return pump; 12-hydrogen source; 13-fuel cell hydrogen inlet.

Detailed ways

The following non-limiting examples may enable those of ordinary skill in the art to more fully understand the present invention, but do not limit the present invention in any way.

It should be noted that the embodiments of the present invention and the features of the embodiments may be combined with each other under the condition of no conflict. The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

In order to make the purposes, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments It is only a part of the embodiments of the present invention, but not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example 1

As shown in FIG. 1 , the present invention provides a fuel cell anode drainage device. The drainage device includes a drainer and a return pump sequentially arranged between the hydrogen outlet 2 and the hydrogen inlet 13 of the fuel cell; the drainer is sequentially provided with a hydrogen chamber I3, a sealant I, a water chamber 5, a sealant II, and a hydrogen chamber along the hydrogen flow direction. II6, the hydrogen chamber I3 and the hydrogen chamber II6 are connected by the hollow fiber bundle 7, the hollow fiber bundle 7 has the function of water permeability and gas resistance when there is a pressure difference in the wet state, and the two ends of the hollow fiber bundle 7 pass through the sealant and are open The sealant I isolates the hydrogen chamber I3 and the water chamber 5; the sealant II isolates the hydrogen chamber II6 and the water chamber 5; the hydrogen chamber I3 is provided with a hydrogen inlet 3, which is connected with the hydrogen outlet 2 of the fuel cell The hydrogen chamber II6 is provided with a hydrogen outlet 10, which is communicated with the hydrogen inlet 13 of the fuel cell through the return pump 11; the water chamber has two interfaces, which are the inlet 9 and outlet 8 of circulating water, and the Outside the hollow fiber tube; in the process of transferring hydrogen from the hydrogen chamber I3 to the hydrogen chamber II6 through the hollow fiber bundle 7, the gaseous water in the hydrogen is condensed into liquid water under the temperature difference of the circulating water, and the liquid water and the liquid water carried by the hydrogen are condensed Under the action of pressure difference, it is discharged into the water cavity 5 through the outer wall of the hollow fiber bundle 7 , and then discharged through the circulating water outlet 8 . Among them, the drain is composed of a polyethersulfone hollow fiber tube, an epoxy resin sealing ring and a plastic shell, and the hollow fiber tube has the function of water drainage and gas blocking in a wet state. Cooling water, drain, hydrogen return pump and stack together form the anode drainage system.

When the system is working, the operating temperature of the alkaline anion exchange membrane fuel cell is 80°C, the anode hydrogen pressure is 0.1MPa gauge pressure, the operating current density is 200mA/cm ² , the reflux pump is a hydrogen circulation pump, and the rotation speed of the circulation pump is 4000 rpm. /every minute. The outlet of the stack is hydrogen with saturated steam and liquid product water at a temperature of 80°C. After passing through the drain, the hydrogen is pressurized by the return pump, and enters the fuel cell stack together with the hydrogen from the hydrogen source. The cooling water temperature is 30°C and the pressure is normal pressure. The condensed water in the circulating hydrogen of the stack anode and the liquid water together penetrate the wall of the hollow fiber tube and enter the circulating water under the pressure difference of 0.1 MPa to realize the anode drainage. Before drainage, the partial pressure of water vapor in hydrogen is 47.4kPa, and contains liquid water; and after drainage, the partial pressure of water vapor is 4.3kPa, and there is no liquid water.

Example 2

The same drainage device as in Example 1 was used. When the system is working, the operating temperature of the alkaline anion exchange membrane fuel cell is 90°C, the anode hydrogen pressure is 0.2MPa gauge pressure, the operating current density is 400mA/cm ² , the return pump is a hydrogen circulation pump, and the rotation speed of the circulation pump is 3500 rpm. /every minute. The outlet of the stack is hydrogen carrying saturated steam and liquid product water at a temperature of 70°C. After passing through the drain, the hydrogen is pressurized by the return pump, and enters the fuel cell stack together with the hydrogen from the hydrogen source. The cooling water temperature was 40°C and the pressure was normal pressure. The condensed water in the circulating hydrogen of the stack anode and the liquid water together penetrate the wall of the hollow fiber tube and enter the circulating water under the pressure difference of 0.2MPa to realize the anode drainage. Before draining, the partial pressure of water vapor in hydrogen was 70.1kPa, and it contained liquid water; and after draining, the partial pressure of water vapor was 7.4kPa, and there was no liquid water.

Claims (4)

1. An alkaline anion exchange membrane fuel cell anode drain, characterized in that the drain comprises a drainer arranged between a fuel cell hydrogen outlet and a hydrogen inlet; the drainer is provided with a water circulation branch;

the drainer is sequentially provided with a hydrogen cavity I, a sealant I, a water cavity, a sealant II and a hydrogen cavity II along the hydrogen flowing direction, the hydrogen cavity I and the hydrogen cavity II are connected through a hollow fiber bundle, the hollow fiber bundle has the functions of water and gas permeation and gas barrier when pressure difference exists in the wet state, and two ends of the hollow fiber bundle are communicated with the sealant and are open pipes; the sealant I isolates the hydrogen cavity I from the water cavity; the hydrogen cavity II and the water cavity are isolated by the sealant II; the hydrogen cavity I is provided with a hydrogen inlet which is communicated with a hydrogen outlet of the fuel cell; the hydrogen cavity II is provided with a hydrogen outlet which is communicated with a hydrogen inlet of the fuel cell; the water cavity is provided with two interfaces which are respectively an inlet and an outlet of circulating water;

the hollow fiber bundle component is at least one of polyether sulfone and poly acetate fiber ester;

the tube wall of the hollow fiber bundle contains micropores, and the pore diameter is less than 1 mu m so as to have capillary force; in the wetted state, the hollow fiber bundle walls are gas-tight at a pressure differential that exceeds the hydrogen pressure.

2. The alkaline anion exchange membrane fuel cell anode drain of claim 1, wherein the drain further comprises a reflux; the backflow device is positioned between the water drainer and the hydrogen inlet of the fuel cell and used for pressurizing the drained hydrogen.

3. The alkaline anion exchange membrane fuel cell anode drain apparatus of claim 2, wherein the reflux device is a hydrogen circulation pump or an ejector.

4. An alkaline anion exchange membrane fuel cell anode drainage system, characterized in that the drainage system comprises a fuel cell stack and the alkaline anion exchange membrane fuel cell anode drainage device of any claim 1 to 3.

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