CN110829897A - A thermoelectric conversion device based on hydrogen ion concentration difference battery - Google Patents

Abstract

A thermoelectric conversion device based on a hydrogen ion concentration battery, comprising a hydrogen ion concentration battery for ionizing hydrogen to generate electric current and a heat exchanger for heating the gas inside the hydrogen ion concentration battery; the hydrogen ion concentration battery Including the proton exchange membrane and the cathode and anode electrodes arranged on both sides of the proton exchange membrane, wherein, the anode electrode is fed with hydrogen to generate 2e ^‑ and 2H ⁺ , the cathode electrode is passed into the inert gas, and the ionized H ⁺ reaches through the proton exchange membrane Cathode electrode, ionized e ^- from the anode electrode through the external circuit to the cathode electrode, where hydrogen gas is regenerated, and in the external circuit, the current used by the electrical device is generated. The heating of the heat exchanger of the invention improves the proton passing rate of the proton exchange membrane, thereby improving the discharge efficiency. The hydrogen is not consumed in the whole reaction, but current is generated in the external circuit. Compared with the traditional waste heat power generation system, the invention has the advantages of high efficiency, no pollution, low noise and the like.

Description

A thermoelectric conversion device based on hydrogen ion concentration difference battery

technical field

The invention relates to the field of thermoelectric conversion, in particular to a thermoelectric conversion device based on a hydrogen ion concentration difference battery.

Background technique

With the worldwide energy shortage, countries are working hard to save energy, reduce emissions, and strive for sustainable development. Based on such a fact, the utilization of waste heat has increasingly become the main direction for countries to tackle, in order to obtain greater and more benefits.

The main reason for my country's energy shortage is the low energy utilization rate and low energy conversion efficiency. 60% to 65% of the industrial energy is converted into waste heat resources, and there is still a lot of room for recycling. There are many ways to utilize waste heat, but at present the most important, meaningful and valuable way of utilization is power generation, but because the technology of low temperature waste heat power generation is relatively backward, it restricts its further development. At present, the most commonly used waste heat power generation method is the ORC system (organic Rankine cycle power generation system), which is different from the traditional steam cycle power generation system and uses an organic working medium as a circulating working medium for power generation. However, this power generation method requires components such as evaporators, condensers, steam turbines (groups), pumps, etc., resulting in relatively low conversion efficiency, large floor space and high cost. At present, as a new power generation device, fuel cells have higher conversion efficiency (60% to 70%) than ordinary power generation methods, and fuel cells do not require boilers and steam turbines during the power generation process. Therefore, it neither It will emit polluting gases and there is no noise interference, and fuel cells have attracted more and more attention.

Gas electrode concentration cell is a special ion concentration fuel cell, such as Pt|H ₂ (P ₁ )|HCI(C)|H ₂ (P ₂ )|Pt, P ₁ >P ₂ , P is the hydrogen pressure , the electromotive force is generated by using the concentration difference between the yin and yang levels of hydrogen. The anode of the electrode is filled with hydrogen, and the hydrogen is ionized into H ⁺ under the condition of the catalyst. The anode reaction is H ₂ -2e ^- = 2H ⁺ , and the cathode of the electrode is filled with an inert gas, such as argon or nitrogen, and H ⁺ passes through the middle. The proton exchange membrane reaches the cathode, e ^- reaches the cathode through the external circuit, and the cathode reaction is 2H ⁺ +2e ^- =H ₂ , and the total electrode reaction is H ₂ =H ₂ , that is, H ₂ arrives from a place with a high concentration to a place with a low concentration. where, the total amount of _H2 did not decrease, but a charge was generated in the process, i.e., the external circuit was discharged. By heating the battery, the proton passing rate of the proton exchange membrane can be increased, thereby improving its discharge efficiency. Therefore, it is possible to improve the discharge efficiency by combining it with waste heat recovery and using waste heat. The experimental study shows that the thermoelectric conversion efficiency is much higher than that of the ORC system.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a kind of thermoelectric conversion device based on hydrogen ion concentration battery to replace the current ORC of waste heat recovery in view of the problem that the utilization rate of waste heat resources is low and the gas electrode concentration battery cannot be effectively utilized in the above-mentioned prior art. The system has high thermoelectric conversion efficiency, no pollution and no noise, and can be used in various waste heat recovery occasions.

In order to achieve the above purpose, the present invention has the following technical solutions based on the thermoelectric conversion device of the hydrogen ion concentration cell:

The thermoelectric conversion device includes a hydrogen ion concentration cell for ionizing hydrogen to generate electric current and a heat exchanger for heating the gas inside the hydrogen ion concentration cell; the hydrogen ion concentration cell includes a proton exchange membrane and a The cathode and anode electrodes on both sides of the proton exchange membrane, wherein the anode electrode is fed with hydrogen to generate 2e ^- and 2H ⁺ , the cathode electrode is passed into inert gas, the ionized H ⁺ passes through the proton exchange membrane to the cathode electrode, and the ionized e ^- From the anode electrode through the external circuit to the cathode electrode, where the hydrogen gas is regenerated and in the external circuit the current for the consumers is generated.

The hydrogen ion concentration battery includes stainless steel plates arranged outside the anode and cathode electrodes, and air guide grooves are provided on the surface of the stainless steel plate, and hydrogen and inert gas reach the anode electrode and the cathode electrode through the air guide grooves on the stainless steel plate respectively.

The heat exchanger adopts a plate heat exchanger, and the stainless steel plates on the outside of the anode and cathode electrodes are sandwiched between the two plate heat exchangers.

The stainless steel plate outside the anode electrode is provided with a hydrogen inlet and a hydrogen outlet, and a hydrogen circuit is connected between the hydrogen inlet and the hydrogen outlet; an inert gas inlet and an inert gas outlet are opened on the stainless steel plate outside the cathode electrode, and the inert gas inlet An inert gas circuit is connected with the inert gas outlet; a hydrogen return pump is arranged on the hydrogen circuit, and an inert gas circulation pump is arranged on the inert gas circuit. The inert gas loop is provided with an inert gas and hydrogen separator, and the separated hydrogen is drawn out of a pipeline and fed into the hydrogen return pump, and then re-entered into the hydrogen inlet through the hydrogen return pump.

The inert gas is nitrogen or argon.

The anode and cathode electrodes are all Pt/C catalytic electrodes, and the outer periphery of the anode and cathode electrodes is surrounded by a sealing gasket made of polytetrafluoroethylene.

The anode and cathode electrodes include carbon paper and a catalyst active layer. A catalyst mixture is obtained by uniformly mixing a Pt/C containing 40wt% of Pt and a Nafion solution of 5wt% with a sufficient amount of ethanol according to a mass ratio of 1:1 and sufficient ethanol through ultrasonic vibration. The mixture was pasted on carbon paper, and air-dried at 60° C. to obtain a catalyst active layer, so that the density of the catalyst reached 24 mg/cm ² .

The proton exchange membrane consists of a polybenzimidazole bulk immersed in an 85 wt% phosphoric acid solution, kept in the solution at room temperature for two days, and then taken out and sealed in a plastic bag to form a PBI-PA proton exchange membrane.

The anode electrode, the proton exchange membrane, and the cathode electrode were pressed in an environment of 1.5 Mpa and 130° C. to form a membrane electrode.

Compared with the prior art, the present invention has the following beneficial effects: heat flow is introduced into the heat exchanger, heat exchange is performed with the anode and cathode electrodes of the hydrogen ion concentration difference battery, the internal gas of the hydrogen ion concentration difference battery is heated by the heat exchanger, and the The proton passing rate of the proton exchange membrane, thereby accelerating the electricity generation efficiency. The ionization reaction occurs when hydrogen gas is introduced into the anode electrode to generate 2e ^- and 2H ⁺ , the cathode electrode is introduced into inert gas, the ionized H ⁺ reaches the cathode electrode through the proton exchange membrane, and the ionized e ^- from the anode electrode through the external circuit to the cathode electrode , hydrogen is regenerated at the cathode electrode. Therefore, in the overall reaction, there is no consumption of hydrogen and nitrogen, and electricity is generated in the external circuit, which is a perfect heat utilization method. In order to reduce heat loss as much as possible, the entire thermoelectric conversion device is wrapped by thermal insulation cotton. The thermoelectric conversion device of the invention can replace the current ORC system for waste heat recovery, is based on a hydrogen ion concentration difference thermal battery, has high thermoelectric conversion efficiency, has no pollution and no noise, and is suitable for various waste heat recovery occasions.

Further, in the present invention, stainless steel plates are arranged on the outside of the anode and cathode electrodes, and air guide grooves are provided on the surface of the stainless steel plate. The air guide grooves are shallow grooves that allow gas to flow, and a tortuous flow channel is arranged inside the stainless steel plate to ensure good heat exchange and improve heat exchange. efficiency.

Further, the anode electrode and the cathode electrode of the present invention are relatively pressed on the proton exchange membrane to form a membrane electrode, the outer periphery of the cathode and anode electrodes are respectively surrounded by sealing gaskets made of polytetrafluoroethylene, and the outer periphery of the membrane electrode between the stainless steel plates is sealed, Reduce leakage.

Description of drawings

In order to illustrate the technical solutions of the present invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are some embodiments of the present invention, which are common in the art. As far as technical personnel are concerned, other drawings can also be obtained based on these drawings without any creative effort.

1 is a schematic diagram of the overall structure of the thermoelectric conversion device of the present invention;

2 is a schematic diagram of the membrane electrode structure of the fuel cell of the present invention;

3 is a schematic diagram of the internal structure of the stainless steel plate of the hydrogen ion concentration battery of the present invention;

In the accompanying drawings: 1- Hydrogen reflux pump; 2- Inert gas circulation pump; 3- Plate heat exchanger; 4- External circuit; 5- Electric device; 6- Inert gas and hydrogen separator; 7- Stainless steel plate; 8 - sealing gasket; 9 - anode electrode; 10 - proton exchange membrane; 11 - cathode electrode.

Detailed ways

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

1-2, the hydrogen ion concentration cell of the present invention includes a proton exchange membrane (PBI-PA), and cathode and anode electrodes are respectively placed at both ends of the proton exchange membrane 10. Both anode and cathode electrodes are Pt/C catalytic electrodes. A membrane electrode (MEA) is formed together with the proton exchange membrane 10. There are two sealing gaskets 8 made of PTFE (polytetrafluoroethylene) on the periphery of the membrane electrode, and there are two stainless steel plates 7 on the outside of the sealing gasket 8. There are shallow grooves on the surface of 7 to allow gas to flow, and there are two plate heat exchangers 3 on the outside of the two stainless steel plates 7 for heat exchange. The interior of the stainless steel plate on the anode side is fed with hydrogen through the hydrogen reflux pump 1, and the interior of the stainless steel plate on the cathode side is fed with inert gas such as nitrogen or argon. The hydrogen enters the stainless steel plate 7 from the hydrogen inlet, and enters the anode electrode 9 of the fuel cell from the shallow groove on the stainless steel plate for ionization. The ionization reaction formula is: H ₂ -2e ^- = 2H ⁺ , and nitrogen acts as an inert gas and enters the stainless steel from the nitrogen inlet. The plate 7 enters the cathode 11 of the fuel cell from the shallow groove inside the stainless steel plate.

The ionized H ⁺ reaches the cathode 11 of the battery through the proton exchange membrane 10; the ionized e- reaches the cathode 11 ^from the anode 9 through the external circuit 4; at the cathode 11, 2H ⁺ +2e- ⁼ H ₂ is generated again at the cathode At the same time, a current is generated in the external circuit 4 for the electrical device 5 to use. The hydrogen generated at the cathode 11 is mixed with the nitrogen introduced into the cathode, and the nitrogen and hydrogen are separated from the nitrogen outlet through the separation device 6. The separated hydrogen is re-pressurized by the hydrogen reflux pump 1 and passed into the hydrogen inlet, and the separated The nitrogen gas is pressurized by the nitrogen circulating pump 2 and then re-introduced into the nitrogen inlet. Therefore, in the overall reaction, there is no consumption of hydrogen and nitrogen, and electricity is generated in the external circuit. In order to speed up the electricity generation efficiency, two plate heat exchangers 3 are respectively arranged outside the stainless steel plate 7, and the stainless steel plate 7 is heated by the plate heat exchanger 3, and then the internal gas is heated to improve the proton passing rate of the proton exchange membrane 10. , to speed up the electricity generation efficiency. In order to make the heat exchange as good as possible, a tortuous flow channel is arranged inside the stainless steel plate 7, as shown in Figure 3, to increase the heat exchange efficiency as much as possible. The anode electrode 9 and the cathode electrode 11 are relatively pressed on the proton exchange membrane 10 to form a membrane electrode, and the sealing gasket 8 arranged between the two sides of the membrane electrode and the stainless steel plate 7 can reduce leakage. In order to minimize heat loss and improve thermoelectric conversion efficiency, the entire device is wrapped in thermal insulation cotton to insulate as much as possible from the outside world.

Argon can also be used as the inert gas in the present invention.

The cathode and anode electrodes of the present invention, as well as the sealing gaskets, stainless steel plates and heat exchangers on both sides are symmetrical with respect to the intermediate proton exchange membrane.

The anode and cathode electrodes of the present invention comprise carbon paper and a catalyst active layer. The catalyst mixture is obtained by uniformly mixing Pt/C containing 40wt% Pt and 5wt% Nafion solution with sufficient ethanol in a mass ratio of 1:1 through ultrasonic vibration. The mixture was pasted on carbon paper and air-dried at 60° C. for 3 hours to obtain a catalyst active layer to ensure that the density of the catalyst reached 24 mg/cm ² , and the electrode fabrication was completed. The proton exchange membrane 10 consists of a polybenzimidazole bulk immersed in an 85 wt% phosphoric acid solution, kept in the solution for two days at room temperature, and then taken out and sealed in a plastic bag to form a PBI-PA proton exchange membrane. The anode electrode 9 , the proton exchange membrane 10 , and the cathode electrode 11 were pressed for 3 minutes in an environment of 1.5 Mpa and 130° C. to form a membrane electrode.

The heating of the heat exchanger of the invention increases the proton passing rate of the proton exchange membrane, thereby improving the discharge efficiency. The hydrogen generated at the cathode is mixed with the inert gas input at the cathode, separated by the separator, and then returned to the anode to participate in the reaction through the hydrogen return pump 1. The hydrogen is not consumed in the whole reaction, but an electric current is generated in the external circuit. Compared with the traditional waste heat power generation system, the device of the invention has the advantages of high efficiency, no pollution, low noise and the like, and has a great application prospect in the field of waste heat power generation.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the technical solutions of the present invention. Those skilled in the art should understand that, without departing from the spirit and principles of the present invention, the technical solutions also Several simple modifications and substitutions can be made, which also fall within the scope of protection defined by the claims.

Claims (10)

1. A thermoelectric conversion device based on a hydrogen ion concentration cell, characterized in that: comprising a hydrogen ion concentration cell for ionizing hydrogen to generate current and a heat exchanger for heating the gas inside the hydrogen ion concentration cell; The hydrogen ion concentration battery comprises a proton exchange membrane (10) and cathode and anode electrodes arranged on both sides of the proton exchange membrane (10), wherein the anode electrode (9) is fed with hydrogen gas to generate 2e ⁻ and 2H ⁺ , and the cathode electrode (9) undergoes an ionization reaction. (11) Inert gas is introduced, the ionized H ⁺ reaches the cathode electrode (11) through the proton exchange membrane (10), and the ionized e- goes ^from the anode electrode (9) through the external circuit (4) to the cathode electrode (11) , the hydrogen gas is regenerated at the cathode electrode (11), and the electric current used by the electrical device (5) is generated in the external circuit (4). 2. The thermoelectric conversion device based on a hydrogen ion concentration cell according to claim 1, wherein the hydrogen ion concentration cell comprises a stainless steel plate (7) arranged on the outside of the anode and cathode electrodes, and the surface of the stainless steel plate (7) is An air guide groove is opened, and the hydrogen gas and the inert gas respectively reach the anode electrode (9) and the cathode electrode (11) through the air guide groove on the stainless steel plate (7). 3. The thermoelectric conversion device based on the hydrogen ion concentration cell according to claim 2, wherein the heat exchanger adopts a plate heat exchanger (3), and the stainless steel plate (7) on the outside of the cathode and anode electrodes is sandwiched between the two. between the plate heat exchangers (3). 4. The thermoelectric conversion device based on hydrogen ion concentration cell according to claim 2, is characterized in that: A hydrogen inlet and a hydrogen outlet are provided on the stainless steel plate (7) outside the anode electrode (9), and a hydrogen circuit is connected between the hydrogen inlet and the hydrogen outlet; the stainless steel plate (7) outside the cathode electrode (11) is provided with There are an inert gas inlet and an inert gas outlet, and an inert gas loop is connected between the inert gas inlet and the inert gas outlet; the hydrogen loop is provided with a hydrogen return pump (1), and the inert gas loop is provided with an inert gas circulation pump ( 2). 5. The thermoelectric conversion device based on a hydrogen ion concentration cell according to claim 4, wherein the inert gas loop is provided with an inert gas and hydrogen separator (6), and the separated hydrogen is passed through a hydrogen return pump (1) Re-enter the hydrogen inlet. 6. The thermoelectric conversion device based on hydrogen ion concentration cell according to claim 1, is characterized in that: The inert gas is nitrogen or argon. 7 . The thermoelectric conversion device based on hydrogen ion concentration cell according to claim 1 , wherein the anode and cathode electrodes are all Pt/C catalytic electrodes, and the outer circumferences of the anode and cathode electrodes are respectively made of PTFE gaskets. 8 . Sheet (8) surrounds. 8. The thermoelectric conversion device based on hydrogen ion concentration difference battery according to claim 1, is characterized in that: The anode and cathode electrodes include carbon paper and a catalyst active layer. A catalyst mixture is obtained by uniformly mixing a Pt/C containing 40wt% of Pt and a Nafion solution of 5wt% with a sufficient amount of ethanol according to a mass ratio of 1:1 and sufficient ethanol through ultrasonic vibration. The mixture was pasted on carbon paper, and air-dried at 60° C. to obtain a catalyst active layer, so that the density of the catalyst reached 24 mg/cm ² . 9. The thermoelectric conversion device based on hydrogen ion concentration cell according to claim 1, is characterized in that: The proton exchange membrane (10) consists of a polybenzimidazole body immersed in an 85wt% phosphoric acid solution, kept in the solution for two days at room temperature, and then taken out and sealed in a plastic bag to form a PBI-PA proton exchange membrane. 10. The thermoelectric conversion device based on a hydrogen ion concentration cell according to claim 1, characterized in that: the anode electrode (9), the proton exchange membrane (10), and the cathode electrode (11) are placed in an environment of 1.5Mpa and 130°C Press down to form the membrane electrode.

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