| With the increasing depletion of fossil resources,the development and utilization of new energy has attached great attention in today’s society.Hydrogen energy is a typical clean energy with high efficiency and low pollution.Water gas shift reaction（WGSR）is the main hydrogen production reaction in industry.It consumes CO and produces hydrogen at the same time.This WGSR method is widely implemented in ammonia synthesis,fuel cell and other fields.However,WGSR is an exothermic reaction,and its equilibrium conversion rate drops sharply at high temperature.Therefore,WGSR in low temperature has become a research hotspot in this field.The core problem is how to improve the reaction rate of WGS in low temperature environment.In this paper,we have proposed the method of combining low temperature plasma with catalytic process to realize the fast reaction of WGS at the temperature below 150℃.Compared with traditional thermal catalysis,low temperature plasma concerted catalysis WGSR can be carried out in low temperature environment,reducing energy consumption.In this paper,the low temperature plasma is produced by dielectric barrier discharge.Firstly,several studied has been carried on to analysis the factors on the water gas reaction without catalyst filling,including,the influence of water gas ratio,discharge length,discharge voltage,energy density,gas flow and other system operation factors.The results show that CO conversion increases with the rise of water gas ratio,discharge length and discharge voltage,and decreases with the surge of gas flow rate.Furthermore,the activity of Ti O2,SAPO-34,Si O2 and Al2O3 catalysts in WGSR was studied.It was found that the order of activity of the catalysts was Ti O2>Al2O3>SAPO-34>pure DBD>Si O2 at the same discharge power.Besides Si O2,the CO conversion in the WGSR was improved with the addition of catalyst.Al2O3-Ti O2composite oxide was prepared.Through the activity test of Al2O3-Ti O2catalyst with different calcination temperature,it was found that Al2O3-Ti O2 catalyst had the best activity when the calcination temperature of catalyst was 600℃.In the experiment of the p H value influence on different mixed salt solution,it was found that Al2O3-Ti O2 catalyst had the best activity when the p H value of mixed salt solution was9.5.The activity of Al2O3-Ti O2 catalyst was tested with different aging time and quality ratio.When the aging time was 5 h and Ti O2 content was 10%,Al2O3-Ti O2 catalyst had the best activity.Meanwhile,we have compared the discharge parameters of empty tube and with catalyst,and analyzed the interaction between plasma discharge and catalyst.As the catalyst being added in the discharge area,the discharge form changes from the typical filamentary discharge to the combination of surface discharge and filamentary discharge,compared with a single Al2O3 catalyst,the 10%Al2O3-Ti O2 catalyst is more conducive to expanding the discharge,generating more corona-like micro-discharge forms,allowing gas molecules to react more fully on the catalyst surface,and the 10%Al2O3-Ti O2 catalyst is more helpful to increase the effective capacitance of a single cycle,in the plasma-catalyzed WGS reaction,more energy can be stored,which enhances the generation of charge,the amount of transfer,and the average electric field strength,promote more active substances and high energy electron,and increase the efficiency of the WGS reaction of input energy,in the order of 10%Al2O3-Ti O2>Al2O3>empty tube,which is related to the higher dielectric constant of Ti O2.The introduction of catalyst affects the physical characteristics of plasma discharge and improves the reaction efficiency of WGSR. |
