Fundamental Research Of Solid Waste Gasification Model Tar Reforming By Rotating Gliding Arc Plasma Coupled With Ni-based Catalysts

Tar is a complex mixture containing a variety of condensable organic compounds produced in municipal solid waste gasification.Its existence leads to the blockage and corrosion of downstream equipment and hinders the wide popularization of gasification technology.Non-thermal plasma catalysis technology is a combination of traditional catalytic method and emerging plasma technology.It has the advantages of relatively high process capability,low specific energy consumption,normal temperature operation,instant on/off,long-term stable operation,and so on.In this study,the rotating gliding arc plasma coupled nickel-based single/bimetallic catalysts is used for the reforming of tar simulation components.Starting from the working condition of toluene reforming in a nitrogen atmosphere,the carrier gas is replaced with simulated gasification gas and the tar surrogate is replaced with complex components,to make the working condition closer to the actual situation and provide reference and guidance for the industrial application of similar technologies.The main contents of this paper are as follows:（1）In order to reasonably combine the catalytic method and non-equilibrium plasma degradation method in tar treatment,the optimal configuration of the rotating sliding arc plasma catalytic coupling system is deeply studied.According to the physical changes of the arc passing through the catalyst surface,the high-speed camera is used to analyze it.It is found that the arc becomes silk-like and the average voltage decreases at the same time.It shows that when the distance between them is too close,it will cause the change of arc discharge morphology and the formation of cathode spots,while if the distance between them is too far,it can not produce a synergistic effect.Therefore,for rotating gliding arc plasma reactors,the requirement of configuring an effective and cooperative catalytic coupling system is more stringent.（2）The effects of specific energy input and Ni loading on the performance of the reactor are studied with toluene as tar surrogate and nitrogen as carrier gas.The optimal conversion and SEC are 94.7%and 49.1 k Wh/kg,respectively,which is of great excellence in similar systems for toluene reforming.Subsequently,after the carrier gas is replaced with simulated gasification gas,the processing capacity of the system decreases,with part of the input energy being used for gas reforming.Compared with the original simulated components（dry basis）,the proportions of CO,CO_2,and CH₄ changed from 12%,15%,and 3%to 22%,8%,and 0.7%,respectively.The optimal selection of various parameters of the coupling system is studied,the shortcomings of the existing literature for evaluating the industrialization of the coupling system are recognized,and the excellent calorific value enhancement ability of the catalyst to the carrier gas is found.（3）Using toluene as tar surrogate and simulated gasification gas as the carrier gas,the effect of the addition of the second metal on the performance of the catalyst is studied.The results showed that the conversion and net increase of calorific value in Ni Cu group is the highest,which are 94.3%and 29.0%,respectively;Ni Co group has the lowest specific energy consumption,which is 64.5 k Wh/kg,and has the best stability.The understanding of the selection basis of the active components of the catalyst in the transition metal is improved,and the advantages of bimetallic catalyst over single metal catalyst in conversion,specific energy consumption,net increase of gas calorific value,stability,and carbon deposition are demonstrated.（4）Using toluene as tar surrogate and simulated gasification gas as the carrier gas,the performance of spherical catalyst and honeycomb catalyst is compared,and then the mass ratio of real tar components is measured.The complex tar mixture is configured to replace toluene,and the effect of Ni/Cu ratio on the performance of the system is tested.Among them,6Ni2Cu group showed excellent catalytic activity,and its overall conversion and specific energy consumption were the best,which are 89.3%and 84.0 k Wh/kg,respectively.The conversion of 6Ni2Cu group was 14.0%higher than that of the non-catalytic group（relative value）.This part of the research provides an important reference for the performance of the coupling system in the real industrial situation.The feasibility of technological industrialization is discussed through economic analysis,literature comparison and expanded application analysis.（5）The liquid by-products of toluene reforming in different atmospheres are analyzed.The difference in toluene reaction path between non-catalytic plasma system and coupling system and its possible mechanism is discussed.Then the activation energy of different paths of toluene reforming on the surface of different bimetallic catalysts is analyzed by DFT simulation.It was found that its activation energy was related to its activity to a certain extent.At the same time,the activation energy of OH radical in different reaction paths on the surface of bimetallic catalysts is calculated,and the difference in liquid products caused by catalyst back-spillover is explained.