The Effect Of Atmosphere And Catalyst On Coal Pyrolysis In A Fluidized Bed

China is a big country of Energy consumption,and coal accounts for over 60%of the total energy consumption.But the use of coal brings us a lot of problems.Coal combustion directly causes the environmental pollution,and has a harmful effect on people's health.Face the energy and economic situation of our country,coal integrated technology is one of the ways to solve the problems,and conforms to the requirements for the long-term development of our country.The fluidized bed multi-generation technology developed by Zhejiang University has the features of high heat transfer rate,good reaction performance of coal and high coal type adaptability.In order to improve the yield and quality of coal tar,we studied the effect of atmosphere and catalyst on coal pyrolysis in fluidized bed.The atmosphere used in the study can be divided into pure atmosphere(N2?H2?CH4?CO2?CO)and mixed atmosphere(CH4+H2?CH4+CO2?CH4+H2+CO2+CO).The atmosphere of coal pyrolysis with 4%Ni/Al2O3 catalyst placed before the reaction segment is CH4?CH4+H2?CH4+H2+CO2+CO respectively.Coal tar is distilled by distillation apparatus for the fraction of before 300?.Light tar is analyzed by GC-MS.Using elemental analysis and scanning electron microscopy can study the element distribution and surface structure of the char.Catalyst is characterized by X-Ray Diffraction,specific surface area measurements,scanning electron microscopy and energy spectrum analysis.The results show as follows:Compared with N2 atmosphere,H2,CO,CH4 and CO2 have different degrees of promoting effect on coal pyrolysis.H2 and CH4 atmosphere at high temperature can increase the content of light component in the tar,and promote the formation of aromatic hydrocarbons.While CO and CO2 atmosphere is conducive to the formation of phenolic substances and aliphatic hydrocarbon in the tar during 700?800?.Mainly H2 in CH4+H2 atmosphere plays a leading role for the promotion of tar quality,and the existence of H2 inhibits the decomposition of CH4.CH4 + CO2 atmosphere can improve the yield of coal tar,but water yield can also increase greatly.Under simulating pyrolysis gas,the experiment has the highest tar yield.Compared with coal pyrolysis without catalyst,adding Ni/Al2O3 into atmosphere can get more tar and promote tar quality.