CN107093757B

CN107093757B - Proton exchange membrane fuel cell waste heat recovery system and method

Info

Publication number: CN107093757B
Application number: CN201710367889.0A
Authority: CN
Inventors: 王彬; 岳晨; 韩东; 蒲文灏; 何纬峰
Original assignee: Nanjing University of Aeronautics and Astronautics
Current assignee: Nanjing University of Aeronautics and Astronautics
Priority date: 2017-05-23
Filing date: 2017-05-23
Publication date: 2023-05-23
Anticipated expiration: 2037-05-23
Also published as: CN107093757A

Abstract

The invention discloses a proton exchange membrane fuel cell waste heat recovery system and a method, and belongs to the field of energy and power. The method is characterized in that: after humidification, hydrogen (2) and air (22) enter an anode reaction chamber (6) and a cathode reaction chamber (8) of the fuel cell respectively to participate in chemical reaction, the fuel cell generates a large amount of heat dissipation during operation, an evaporation chamber (15) is arranged outside the proton exchange membrane fuel cell, dilute solution is introduced into the evaporation chamber (15) to absorb the heat dissipation of the fuel cell, so that the heat dissipation problem of the fuel cell is solved, and concentrated solution can be prepared. The water vapor (11) generated in the evaporating chamber (15) passes through the expander (12), expands in the expander (12) to output work, and enters the condenser (13) for cooling, so that purified water can be obtained. Compared with the conventional system, the invention has the advantages that the evaporation flow and the working flow are increased, the heat dissipation problem of the fuel cell part is solved, the power generation efficiency of the fuel cell is improved, the electric energy and the mechanical energy are obtained, and the concentrated solution and the purified water can be prepared.

Description

Proton exchange membrane fuel cell waste heat recovery system and method

Technical Field

The invention relates to a proton exchange membrane fuel cell waste heat recovery system and a method, belonging to the field of energy and power.

Background

Thermal power stations require that the generator sets be large enough in order to pursue higher power generation efficiency, which limits the flexibility of the thermal power station towards users, while also emitting harmful substances. Compared with the traditional thermal power generation, the fuel cell power generation has a plurality of advantages, and the fuel cell power generation can be used for directly converting chemical energy into chemical energy without burning or rotating parts, so that the energy conversion efficiency is high; the power generation output is determined by the output and the number of groups of the battery stacks, the capacity of the unit can be flexibly adjusted according to the needs, the degree of freedom is high, and the capacity can be as small as supplying power to a mobile phone and is as large as compared with a thermal power plant; the size of the unit has little influence on the power generation efficiency, and can keep higher power generation efficiency; under different loads, the fuel cell can also have higher power generation efficiency; the load response is fast, the operation quality is high, the emission is mainly water and carbon dioxide, and the environmental pollution is small.

In proton exchange membrane fuel cells, the quality of thermal management is an important factor affecting performance. The heat accumulation of the fuel cell can raise the temperature of the cell, dehydrate, shrink and even break the electrolyte membrane, and simultaneously, the recovery of the waste heat discharged by the fuel cell is beneficial to improving the power generation efficiency of the fuel cell. Therefore, designing a suitable system to carry away and recover the waste heat of the fuel cell is of great significance to the development and application of the fuel cell.

About 40% -50% of energy in the fuel cell is dissipated as heat, and the heat mainly comes from three aspects, namely chemical reaction heat emitted by chemical reaction of the electrode, joule heat generated after the circuit is electrified, and heat brought by humidified air. In order to prevent waste heat accumulation, overheat of the battery affects battery performance and service life, and proper heat dissipation means are needed to discharge heat. The conventional heat removal is mainly carried out in three directions by adopting a cooling plate with a channel in the electric pile, and the electrode reaction waste gas is discharged to take away part of heat, and the heat is naturally exchanged by convection on the outer surface of the battery or is cooled by cooling water. The former increases the complexity and cost of the system and also reduces the efficiency of the system, and the heat dissipation requirements are not met by natural convection of the exhaust gas and the surface, so that other effective ways for improving the heat dissipation efficiency are required to be sought.

Disclosure of Invention

The invention aims to provide a multifunctional energy-saving waste heat recovery system and method for a proton exchange membrane fuel cell. A proton exchange membrane fuel cell waste heat recovery system, characterized by: the system comprises a hydrogen storage tank, a valve A, a mixer, a humidifier A, a proton exchange membrane, an expander, a condenser, a condensed water storage tank, an evaporation chamber, a valve B, a concentrated solution storage tank, a valve C, a dilute solution storage tank, a humidifier B and a compressor; the two sides of the proton exchange membrane are respectively provided with an anode reaction chamber and a cathode reaction chamber; the proton exchange membrane, the anode reaction chamber and the cathode reaction chamber form a main body part of the fuel cell, and an evaporation chamber is arranged outside the fuel cell; the hydrogen storage tank is connected with a first inlet of the mixer through a valve A, an outlet of the mixer is connected with an inlet of the humidifier A, an outlet of the humidifier A is connected with an inlet of an anode reaction chamber of the fuel cell, and an outlet of the anode reaction chamber is connected with a second inlet of the mixer; the inlet of the compressor is connected with the atmosphere, the outlet of the compressor is connected with the inlet of the humidifier B, the outlet of the humidifier B is connected with the inlet of the cathode reaction chamber of the fuel cell, and the outlet of the cathode reaction chamber of the fuel cell is connected with the ambient atmosphere; the dilute solution storage tank is connected with the inlet of the evaporating chamber through a valve C, and the solution outlet of the evaporating chamber is connected with the concentrated solution storage tank through a valve B; the steam outlet of the evaporating chamber is connected with the inlet of the expander, the outlet of the expander is connected with the hot side inlet of the condenser, and the hot side outlet of the condenser is connected with the condensed water storage tank.

The working method of the proton exchange membrane fuel cell waste heat recovery system is characterized by comprising the steps of

The method comprises the following steps: air enters a humidifier B after being compressed by a compressor and then enters a cathode reaction chamber of the fuel cell; hydrogen enters an inlet at one side of a mixer from a hydrogen storage tank through a valve A, is mixed with waste gas discharged from an anode reaction chamber at the other inlet of the mixer, is humidified by a humidifier A, enters an anode reaction chamber of a fuel cell, protons in the hydrogen and water are combined and enter a cathode reaction chamber through a proton exchange membrane to react, electrons are externally supplied with power through a fuel cell power supply auxiliary system, and then enter the cathode reaction chamber to react with oxygen in the air to release heat, so that water is generated; the anode waste gas is discharged into a mixer and mixed with fresh hydrogen to participate in the reaction again; the dilute solution enters an evaporation chamber from a dilute solution storage tank through a valve C, heat released by chemical reaction is absorbed in the evaporation chamber to evaporate, evaporated concentrated solution enters a concentrated solution storage tank through a valve B, water vapor enters an expander through a vapor outlet of the evaporation chamber, expands in the expander and acts on the outside, the water vapor enters a condenser from the outlet of the expander, and is condensed into liquid by heat release in the condenser, and the liquid is collected by a condensed water storage tank.

Compared with the conventional system, the proton exchange membrane fuel cell waste heat recovery system has the advantages that the evaporation chamber is arranged on the outer side of the fuel cell, waste heat of the fuel cell is taken away, and meanwhile, the effect of concentrating a dilute solution is achieved. The evaporated water vapor is used as a working medium, enters an expansion machine for expansion, can output work outwards, cools and condenses the expanded water vapor, and can collect purified water. In addition, the waste gas discharged from the anode reaction chamber is mixed with fresh hydrogen and reenters the anode reaction chamber to participate in the reaction, so that the residual hydrogen in the anode waste gas can be recovered, and the raw materials are saved.

The system can solve the problem of partial heat dissipation of the fuel cell by utilizing the evaporating chamber, can be used for a condensation process to obtain concentrated solution and purified water, and can also do work externally. The power generation efficiency of the fuel cell is improved, and various products are obtained.

Drawings

FIG. 1 is a schematic diagram of a proton exchange membrane fuel cell waste heat recovery system according to the present invention;

reference numerals in the figures: 1. hydrogen storage tank 2, hydrogen, 3, valve a,4, mixer 5, humidifier a,6, anode reaction chamber, 7, proton exchange membrane, 8, cathode reaction chamber, 9, anode exhaust gas, 10, cathode exhaust gas, 11, steam, 12, expander, 13, condenser, 14, condensate storage tank, 15, evaporation chamber, 16, valve B,17, rich solution storage tank, 18, valve C,19, lean solution storage tank, 20, humidifier B,21, compressor, 22, air.

Detailed Description

The operation of the proton exchange membrane fuel cell waste heat recovery system will be described with reference to the accompanying drawings.

Valve A3 is opened, valve B16 is opened, and valve C18 is opened.

Air 22 is compressed by a compressor 21, enters a humidifier B20, and then enters the fuel cell cathode reaction chamber 8; the hydrogen 2 enters a first inlet of the mixer 4 from the hydrogen storage tank 1 through a valve A3, is mixed with waste gas 9 discharged from an anode reaction chamber 6 at a second inlet of the mixer 4, is humidified by a humidifier A5, enters the anode reaction chamber 6 of the fuel cell, protons in the hydrogen enter a cathode reaction chamber 8 through a proton exchange membrane 7 to react with air 22, heat is released, electrons are externally supplied with power through a fuel cell power supply auxiliary system, and the anode waste gas 9 is discharged into the mixer 4 for recycling; the dilute solution enters an evaporation chamber from a dilute solution storage tank 19 through a valve C18, heat of chemical reaction is absorbed in the evaporation chamber 15 to evaporate, evaporated concentrated solution enters a concentrated solution storage tank 17 through a valve B16, water vapor 11 enters an expansion machine 12 through a vapor outlet of the evaporation chamber 15, expands in the expansion machine 12 and acts on the outside, the water vapor 11 enters a condenser 13 from an outlet of the expansion machine 12, and is condensed into liquid by heat release in the condenser 13, and the liquid is collected by a condensed water storage tank 14.

The system is additionally provided with the evaporation chamber on the basis of the proton exchange membrane fuel cell, can recover the reaction heat of the fuel cell, evaporates the dilute solution by utilizing the reaction heat of the fuel cell, and applies work to high-temperature water vapor through the expander, so that the system can concentrate the dilute solution while generating power through the fuel cell, and applies work to the outside through the expander.

Claims

1. The working method of the proton exchange membrane fuel cell waste heat recovery system is characterized by comprising the following steps of:

the system comprises a hydrogen storage tank (1), a valve A (3), a mixer (4), a humidifier A (5), a proton exchange membrane (7), an expander (12), a condenser (13), a condensed water storage tank (14), an evaporation chamber (15), a valve B (16), a concentrated solution storage tank (17), a valve C (18), a dilute solution storage tank (19), a humidifier B (20) and a compressor (21); the two sides of the proton exchange membrane (7) are respectively provided with an anode reaction chamber (6) and a cathode reaction chamber (8); the proton exchange membrane (7), the anode reaction chamber (6) and the cathode reaction chamber (8) form a main body part of the fuel cell, and an evaporation chamber (15) is arranged outside the fuel cell;

the hydrogen storage tank (1) is connected with a first inlet of the mixer (4) through the valve A (3), an outlet of the mixer (4) is connected with an inlet of the humidifier A (5), an outlet of the humidifier A (5) is connected with an inlet of the anode reaction chamber (6) of the fuel cell, and an outlet of the anode reaction chamber (6) is connected with a second inlet of the mixer (4); an inlet of the compressor (21) is connected with the atmosphere, an outlet of the compressor (21) is connected with an inlet of the humidifier B (20), an outlet of the humidifier B (20) is connected with an inlet of the fuel cell cathode reaction chamber (8), and an outlet of the fuel cell cathode reaction chamber (8) is connected with the ambient atmosphere; the dilute solution storage tank (19) is connected with the inlet of the evaporation chamber (15) through a valve C (18), and the solution outlet of the evaporation chamber (15) is connected with the concentrated solution storage tank (17) through a valve B (16); the steam outlet of the evaporation chamber (15) is connected with the inlet of the expansion machine (12), the outlet of the expansion machine (12) is connected with the hot side inlet of the condenser (13), and the hot side outlet of the condenser (13) is connected with the condensed water storage tank (14);

the working method comprises the following steps:

air (22) enters the humidifier B (20) after being compressed by the compressor (21), and then enters the cathode reaction chamber (8) of the fuel cell; the hydrogen (2) enters an inlet at one side of a mixer (4) from a hydrogen storage tank (1) through a valve A (3), is mixed with waste gas discharged from an anode reaction chamber (6) at the other inlet of the mixer (4), is humidified by a humidifier A (5), enters an anode reaction chamber (6) of a fuel cell, protons in the hydrogen (2) and water are combined and enter a cathode reaction chamber (8) through a proton exchange membrane (7) to react, electrons are externally supplied by a fuel cell power supply auxiliary system, and then enter the cathode reaction chamber (8) to react with oxygen in air (22) to release heat, so that water is generated; the anode exhaust gas (9) is discharged into a mixer (4) and mixed with fresh hydrogen (2) to participate in the reaction again; the dilute solution enters an evaporation chamber (15) from a dilute solution storage tank (19) through a valve C (18), heat released by chemical reaction is absorbed in the evaporation chamber (15) to evaporate, the evaporated concentrated solution enters a concentrated solution storage tank (17) through a valve B (16), water vapor (11) enters an expansion machine (12) through a vapor outlet of the evaporation chamber (15), expands in the expansion machine (12) and does work to the outside, the water vapor (11) enters a condenser (13) from an outlet of the expansion machine (12), and is condensed into liquid by heat release in the condenser (13) and is collected by a condensed water storage tank (14).