Integrated Analysis Of Chemical Looping Hydrogen Production And Fuel Cell System

As a new efficient and clean power generation technology,fuel cell has been widely used in aerospace,vehicle transportation,electronic communication and other fields.Because it directly converts the chemical energy of fuel into electric energy,it is not limited by the Carnot cycle effect,so the energy utilization efficiency is high.The best energy source of fuel cell is hydrogen.However,hydrogen is a secondary energy.It needs to be produced by various hydrogen production processes,and then compressed,stored and transported before it can be applied to fuel cell.Therefore,in order to improve the efficiency of energy utilization,the integration of hydrogen production system and fuel cell system has become one of the important directions of fuel cell development.In this paper,a new integrated system of hydrogen production by chemical looping of methane and solid oxide fuel cell is proposed.The matching mechanism of the new system is studied,and the influence of important parameters on the performance of the new system is analyzed.The main contents of this paper are as follows:(1)The basic structure of the integrated system of chemical looping hydrogen production and solid oxide fuel cell is constructed,and the matching process of each subsystem is designed.Solid oxide fuel cell can not only obtain the hydrogen produced by chemical looping hydrogen production system,but also input the waste heat generated by itself into chemical looping hydrogen production system to drive the hydrogen production reaction,which can not only realize the cascade utilization of energy and waste heat recovery It can also achieve zero energy consumption capture of carbon dioxide;(2)Aspen Plus software is used to model and simulate the integrated system of chemical looping hydrogen production and solid oxide fuel cell.The important parameters of the integrated system are analyzed by the method of exergy analysis.It is concluded that the power generation efficiency of the new system reaches 61.2%,which is 18% higher than the reference system.The results show that when the flow ratio of oxygen carrier to methane is8 and the cell temperature is 900 ℃,the power generation efficiency of the integrated system is the highest;(3)The key process of hydrogen production by chemical chain in the integrated system was studied experimentally.The physical morphology of oxygen carrier before and after cyclic reaction was analyzed by scanning electron microscope.The results showed that the oxygen carrier particles with inert carrier not only did not appear sintering phenomenon,but also made the reaction more efficient because of the attachment of small particles on the surface to large particles;(4)The performance of proton exchange membrane fuel cell under different working conditions was studied experimentally,which made the preliminary work for the future hydrogen production and proton exchange membrane fuel cell complementary.The effects of anode back pressure,cell temperature and hydrogen concentration on the performance of PEMFC were analyzed.The results show that the optimal temperature of PEMFC is about62 ℃.Too high or too low will reduce the performance of PEMFC.Higher anode back pressure and appropriate temperature are the conditions to improve the performance of PEMFC.The decrease of hydrogen concentration will decrease the performance of PEMFC,but increase the gas emission The effect of hydrogen concentration can be reduced by increasing the amount of hydrogen.