CN106299422B - A kind of electrochemistry tail gas recycling device - Google Patents

Abstract

The invention discloses an electrochemical tail gas recovery and utilization device, which comprises: a casing, a first current collector and a second current collector arranged in the casing respectively adjacent to both sides of the casing, and a first collector and a second collector arranged between the first collector and the second collector. n adjacent repeating unit components between two current collectors, wherein, n is a natural number ≥ 1. One side of the housing is provided with an exhaust gas inlet, and the other side is provided with an exhaust gas outlet. Both the upper ends of the first current collector and the second current collector are exposed outside the housing and connected to an external power source. The repeating unit assembly includes: a collection chamber, an enrichment chamber and an electrochemical reaction assembly arranged between the collection chamber and the enrichment chamber. The electrochemical reaction component is used for electrochemical reaction to enrich hydrogen or oxygen. The device of the invention can realize the recovery and utilization of hydrogen and oxygen, reduce the discharge of tail gas, reduce air pollution, realize the repeated utilization of resources at the same time, reduce the cost, and have high practical value.

Description

An electrochemical tail gas recycling device

technical field

The invention relates to the technical field of fuel cells, in particular to an electrochemical tail gas recycling device for fuel cells.

Background technique

Fuel cell (Fuel Cell, FC) is a new type of power generation device that directly converts fuel chemical energy into electrical energy through electrochemical methods. It has the advantages of high energy conversion rate, no pollution, and rich sources of raw materials. The fourth generation of power generation technology after thermal power and nuclear power. As a new generation of power generation technology, fuel cells can be widely used in portable mobile power, electric vehicles, power stations, aerospace and military ships and other aspects.

Proton exchange membrane fuel cell (PEMFC) is a kind of fuel cell. Its electrolyte is made of solid polymer membrane, so it is also called solid polymer electrolyte fuel cell (SPEFC). It has high power density , low operating temperature (< 100°C), long life and other advantages, it is the most widely studied fuel cell at present. A PEMFC power generation device or system consists of a fuel cell stack and its corresponding auxiliary systems. The fuel cell stack is a power conversion unit that converts chemical energy into electrical energy. The auxiliary system mainly includes a hydrogen support system, an oxygen (air) support system, and a thermal management system to ensure the effective operation of the battery stack.

Using hydrogen as fuel and oxygen as oxidant is the most ideal reactant for fuel cells. When a hydrogen-oxygen fuel cell is working, it converts chemical energy into electrical energy through hydrogen and oxygen electrode reactions while generating water and waste heat. Non-reactive substances do not participate in the electrochemical reaction, and the accumulation in the battery will significantly affect the performance of the battery or even fail. In order to eliminate the inert gas and impurities accumulated in the stack, the tail gas discharge function is set in the hydrogen support system and oxygen support system. However, since tail gas emission is a waste of the reactants, the current common practice is to impose strict requirements on the raw materials of the reactants (the purity is generally required to reach more than 99.99%, which poses a challenge to the production, transportation and storage of the reactant raw materials. high requirements), in order to reduce the exhaust emissions as much as possible, but it is still unavoidable to discharge a part of the exhaust.

Contents of the invention

The purpose of the present invention is to provide an electrochemical tail gas recovery and utilization device, which can reduce the amount of tail gas emissions, and re-participate in the fuel cell reaction by selectively enriching and pressurizing the hydrogen and oxygen in the tail gas discharged from the fuel cell. , effectively improving the utilization of reactants.

In order to achieve the above object, the present invention provides an electrochemical tail gas recovery and utilization device, which comprises:

case,

a first current collector and a second current collector disposed in the housing respectively adjacent to both sides of the housing, and

n adjacent repeating unit assemblies arranged between the first current collector and the second current collector, wherein n is a natural number ≥ 1.

Wherein, one side of the housing is provided with an exhaust gas inlet, and the other side is provided with an exhaust gas outlet.

Wherein, the upper ends of the first current collector and the second current collector are both exposed outside the housing and connected to an external power source.

Wherein, the repeating unit assembly includes: a collection chamber, an enrichment chamber, and an electrochemical reaction assembly arranged between the collection chamber and the enrichment chamber.

Wherein, the electrochemical reaction component is used for electrochemical reaction to enrich hydrogen or oxygen.

One side of the collection chamber is provided with a first flow field.

A second flow field opposite to the first flow field of the collection chamber is provided on one side of the enrichment chamber.

The structures of the first flow field and the second flow field are any one of rectangular cavities, circular cavities, dotted flow fields or parallel groove flow fields.

When n=1, the first current collector and the second current collector are arranged adjacent to the inner sides of the collection cavity and the enrichment cavity respectively, and at this time, the first current collector and the second current collector are both Porous or net-like structure, the collection cavity and enrichment cavity are respectively integrated with the housing, and both the collection cavity and the enrichment cavity are made of insulating materials.

One side of the collection chamber is provided with a first flow field, and the other side is provided with an inlet.

One side of the enrichment chamber is provided with a second flow field, and the other side is provided with an inlet.

When n≥2, both the collection chamber and the enrichment chamber are made of conductive materials, and the adjacent collection chamber and the enrichment chamber are integrated as a whole.

The electrochemical reaction assembly includes: an anode gas diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer and a cathode gas diffusion layer;

Wherein, the proton exchange membrane includes: a central active reaction area and surrounding exposed areas.

The enrichment chamber can withstand a maximum bias voltage of +0.5MPa relative to the collection chamber.

The present invention provides an electrochemical tail gas recovery and utilization device, which solves the waste problem of tail gas discharge in fuel cells, and has the following advantages:

The device is equipped with electrochemical reaction components, which can purify the oxygen and hydrogen in the tail gas; through the gas enrichment chamber, the enrichment of oxygen and hydrogen can be realized; compared with the collection chamber, the enrichment chamber can withstand the highest + The bias voltage of 0.5MPa can cover the working pressure range of most proton exchange membrane fuel cells at present, so the gas recovered by the recovery device can be directly pressurized to the inlet pressure of the fuel cell for recycling; Electrochemical reaction, collecting and enriching hydrogen and hydrogen; the device is not only beneficial to improve the utilization rate of fuel cell reactants, but also improves safety for the application of fuel cells in closed spaces where hydrogen or oxygen is not allowed to be discharged.

Description of drawings

Fig. 1 is a structural schematic diagram of an electrochemical tail gas recycling device for recovering oxygen provided by the present invention.

Fig. 2 is a structural schematic diagram of an electrochemical tail gas recycling device for recovering hydrogen provided by the present invention.

Fig. 3 is a three-dimensional structure diagram of an electrochemical tail gas recycling device for recovering hydrogen provided by the present invention.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the drawings and embodiments.

Example 1

An electrochemical tail gas recovery and utilization device with a simple structure (n=1) of the present invention is used for recovering oxygen in the tail gas.

As shown in Figure 1, a kind of electrochemical tail gas recycling device provided by the present invention, this device comprises:

1 repeating unit assembly 40, the repeating unit assembly 40 includes: a collection chamber 41, an enrichment chamber 43, and an electrochemical reaction assembly 42 arranged between the collection chamber 41 and the enrichment chamber 43; adjacent to the collection chamber 41 and the enrichment chamber The first current collector 20 and the second current collector 30 are arranged on the inside of 43 respectively, and the upper ends of the first current collector 20 and the second current collector 30 are exposed outside the housing 10 and connected to an external power source.

Wherein, the first current collector 20 and the second current collector 30 are porous or reticular, made of titanium alloy, and prepared by laser etching.

Wherein, the collection chamber 41 and the enrichment chamber 43 are respectively integrated with the housing 10 , and both the collection chamber 41 and the enrichment chamber 43 are made of insulating materials. The insulating material is any one or two or more of polycarbonate, epoxy resin or organic glass.

One side of the collection chamber 41 is provided with a first flow field, and the other side is provided with an inlet 411 . One side of the enrichment chamber 43 is provided with a second flow field, and the other side is provided with an outlet 431 . The first flow field is set opposite to the second flow field. The enrichment chamber 43 can withstand a maximum bias of +0.5MPa relative to the collection chamber 41, which can cover the current working pressure range of most proton exchange membrane fuel cells (+0.1MPa~+0.3MPa), so the gas recovered by the recovery device It can be directly boosted to the inlet pressure of the fuel cell for recycling. At present, in the prior art, the pressure of the enrichment chamber and the collection chamber is the same, and it is necessary to add a pressure device to input the enriched gas to the fuel cell, but the device of the present invention can realize the enriched gas without a pressure device. input into the fuel cell.

The electrochemical reaction component 42 includes: an anode gas diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, or a cathode gas diffusion layer. Among them, the proton exchange membrane includes: the central active reaction area and the surrounding exposed area, and the surrounding exposed area is provided with tightly bonded gaskets and fasteners. Under the pressure of the fasteners, the gasket enhances the sealing of the entire device . The electrochemical reaction component 42 is used for electrochemical reaction to enrich oxygen.

The working principle of the electrochemical tail gas recovery and utilization device to recover oxygen is:

The inlet 411 of the electrochemical tail gas recycling device is connected to the fuel cell oxygen tail gas discharge port, and the outlet 431 is connected to the fuel cell oxygen inlet. Connect the first current collector 20 close to the oxygen exhaust outlet side to the negative pole of the DC power supply, and the second current collector 30 close to the oxygen inlet side of the fuel cell to the positive pole of the DC power supply, and load an appropriate DC power supply voltage according to the exhaust gas pressure or oxygen concentration , so that the electrochemical reaction in the electrochemical component 42 is continuously performed.

When the electrochemical reaction module 42 recovers oxygen, the reaction process that occurs is that the oxygen in the exhaust gas on the cathode side (towards the collection chamber 41) reacts with the hydrogen ions in the proton exchange membrane and the electrons conducted by the current collector to generate water, which penetrates through the protons The exchange membrane reaches the anode side (towards the enrichment chamber 43) and decomposes to generate oxygen, hydrogen ions and electrons. The hydrogen ions reversely permeate to the cathode to continue to participate in the reaction, and make the pressure of the enrichment chamber 43 greater than the pressure of the collection chamber 41, thereby realizing Purify and enrich oxygen from exhaust gas for fuel cell cycle.

Example 2

An electrochemical tail gas recovery and utilization device with a complex structure (n≥2) of the present invention is used to recover hydrogen in the tail gas.

As shown in Figure 2 and Figure 3, a kind of electrochemical tail gas recycling device provided by the present invention, this device comprises:

housing 10,

a first current collector 20 and a second current collector 30 disposed on both sides of the casing 10, and

n adjacent repeating unit assemblies 40 are arranged between the first current collector 20 and the second current collector 30 .

Wherein, an exhaust gas inlet 11 is arranged on one side of the housing 10 , and an exhaust gas outlet 12 is arranged on the other side.

Wherein, the upper ends of the first current collector 20 and the second current collector 30 are both exposed outside the casing 10 and connected to an external power source.

Wherein, the repeat unit assembly 40 includes: a collection chamber 41 , an enrichment chamber 43 and an electrochemical reaction assembly 42 arranged between the collection chamber 41 and the enrichment chamber 43 . Both the collection chamber 41 and the enrichment chamber 43 are made of conductive materials, and the adjacent collection chamber 41 and the enrichment chamber 43 are integrated as a whole.

The electrochemical reaction assembly 42 includes: an anode gas diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer, and a cathode gas diffusion layer. The proton exchange membrane includes: the central active reaction area and the surrounding exposed area, and the surrounding exposed area is provided with tightly bonded gaskets and fasteners, and the gasket enhances the sealing performance of the entire device under the pressure of the fasteners. The electrochemical reaction assembly 42 is used for electrochemical reaction to enrich hydrogen.

Both the upper ends of the first current collector 20 and the second current collector 30 are exposed outside the casing 10 . The first current collector 20 and the second current collector 30 are made of pure copper. The housing structure 10 is made of insulating material (preferably epoxy resin) and processed by a CNC milling machine.

One side of the collection chamber 41 and the enrichment chamber 43 are respectively provided with a first flow field and a second flow field, and the first flow field and the second flow field are oppositely arranged. Both the first flow field and the second flow field are parallel groove flow fields. The collection chamber 41 and the enrichment chamber 43 are made of titanium alloy and are manufactured by sheet stamping. Compared with the collection chamber 41, the enrichment chamber 43 can withstand a bias voltage of +0.5MPa at most, which can cover the working pressure of most current proton exchange membrane fuel cells. Range (+0.1MPa~+0.3MPa), so the gas recovered by the recovery device can be directly pressurized to the inlet pressure of the fuel cell for recycling. At present, in the prior art, the pressure of the enrichment chamber and the collection chamber is the same, and it is necessary to add a pressure device to input the enriched gas to the fuel cell. However, the device of the present invention can realize the enriched gas without a pressure device. input into the fuel cell.

The working principle of hydrogen recovery by the electrochemical tail gas recovery and utilization device is as follows:

The tail gas inlet 11 of the electrochemical tail gas recycling device is connected to the outlet of the pre-buffer tank, the tail gas outlet 12 is connected to the inlet of the rear buffer tank, and the inlet of the front buffer tank is connected to the hydrogen exhaust outlet of the fuel cell, The outlet of the rear buffer tank is connected to the hydrogen inlet of the fuel cell. Connect the first current collector 20 close to the hydrogen exhaust outlet side to the positive pole of the DC power supply, and the second current collector 30 close to the hydrogen inlet side of the fuel cell to the negative pole of the DC power supply; according to the exhaust gas pressure or hydrogen concentration, load a suitable DC power supply voltage , allowing the reaction to proceed continuously in the electrochemical assembly.

When the electrochemical reaction component 42 recovers hydrogen, the reaction process that occurs is that the hydrogen in the exhaust gas on the anode side (towards the collection chamber 41) decomposes to form hydrogen ions and electrons, and the hydrogen ions are conducted through the proton exchange membrane to reach the cathode side (towards the enrichment chamber 41). chamber 43) recombines with electrons to generate hydrogen, because other gases on the anode side cannot pass through the ion-selective proton exchange membrane, and make the pressure of the enrichment chamber 43 greater than the pressure of the collection chamber 41, thereby realizing the purification of hydrogen from the tail gas And enriched for fuel cell recycling.

In summary, the present invention is used to provide an electrochemical tail gas recovery and utilization device, which can realize the purification and enrichment of oxygen and hydrogen in fuel cell tail gas, save resources, reuse the purified oxygen and hydrogen, and improve The utilization rate of the reactant.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (7)

1. An electrochemical tail gas recycling device, characterized in that the device comprises: housing (10), The first current collector (20) and the second current collector (30) arranged in the housing (10) adjacent to both sides of the housing (10), and n adjacent repeating unit assemblies (40) arranged between the first current collector (20) and the second current collector (30), wherein n is a natural number ≥ 2; An exhaust gas inlet (11) is arranged on one side of the housing (10), and an exhaust gas outlet (12) is arranged on the other side; The upper ends of the first current collector (20) and the second current collector (30) are exposed outside the housing (10) and connected to an external power source; The repeating unit assembly (40) comprises: a collection chamber (41), an enrichment chamber (43) and an electrochemical reaction assembly (42) arranged between the collection chamber (41) and the enrichment chamber (43); The electrochemical reaction component (42) is used for electrochemical reaction to enrich hydrogen or oxygen. 2. The electrochemical tail gas recovery and utilization device according to claim 1, characterized in that a first flow field is provided on one side of the collection chamber (41). 3. The electrochemical tail gas recycling device according to claim 2, characterized in that, one side of the enrichment chamber (43) is provided with a second flow field opposite to the first flow field of the collection chamber (41). field. 4. The electrochemical tail gas recycling device according to claim 3, characterized in that, the structures of the first flow field and the second flow field are rectangular cavities, circular cavities, point-like distribution Either flow field or parallel groove flow field. 5. The electrochemical tail gas recovery and utilization device according to claim 1, characterized in that, the collection chamber (41) and the enrichment chamber (43) all adopt conductive materials, and the adjacent collection chamber (41) and the enrichment chamber The cavity (43) is integrated into a whole. 6. The electrochemical tail gas recycling device according to claim 1, characterized in that, the electrochemical reaction assembly (42) comprises: an anode gas diffusion layer, an anode catalyst layer, a proton exchange membrane, a cathode catalyst layer and a cathode gas diffusion layer; The proton exchange membrane includes: a central active reaction area and surrounding exposed areas. 7. The electrochemical tail gas recovery and utilization device according to claim 1, characterized in that, the enrichment chamber (43) can withstand a maximum bias voltage of +0.5MPa relative to the collection chamber (41).