Co-production Of Hydrogen-rich Gas And Porous Carbon By Partial Gasification Of Coal Char And Pine Sawdust

China's coal resources are abundant,but their comprehensive utilization leaves much to be desired,resulting in resource waste at a certain extent accompanying with serious environmental problems.Coal pyrolysis is a potential way for clean coal conversion and utilization,and coal char,which is the main product of medium-low temperature pyrolysis of coal,is currently facing the problems and challenges of overcapacity.In order to realize the high-value utilization of coal char,this work based on the development of catalytic coal gasification proposed that co-generation of hydrogen-rich gas and porous carbon by steam partial gasification of coal char.In this thesis,the effects of K2CO3,Ca O,Ni and Ce O2 as single-component catalysts were investigated on co-production of hydrogen-rich gas and porous carbon in gasification of coal char.K2CO3 shows the best catalytic performance among the catalysts.At the following conditions,the steam flow rate of R3,the mass ratio of coal char and K2CO3 being 1.00:0.75,and the reaction temperature of 700 °C,the H2 generation rate can up to 3.2-3.5 mmol/(min·gCC).The specific surface area and pore volume of the resultant porous carbon can reach 812 m2/g and 0.473 cm3/g,respectively,close to the surface and structural properties of the commercial porous carbon.The effects of K-Ca,K-Ni and K-Ce catalysts were also investigated on partial gasification of coal char.Specially,two types of bed packing methods were designed and studied for the K-Ca catalysts.The results show that the packing pattern II is conducive to seperation of the solid residual coke(or semi-finished porous carbon products)and Ca O sorption bed after the gasification reaction.Meanwhile,the surface and structural properties of the resultant porous carbon is not greatly affected.The K-Ni catalyst prepared by the impregnation method can improve the dispersity of the catalyst components,thereby improving the catalytic stability.In this paper,pine sawdust was used as a substitute of coal char,and the effects of several catalysts were investigated on the gasification performance.It was found that K2CO3 was more favorable for the gasification of PS under higher temperature conditions.Hydrogen production rate was up to 0.59 mmol/(min·gPS),and the amount of hydrogen production can be up to 52 mmol/g PS within 120 min.However,due to the high reaction temperature and long reaction time,the carbon conversion of PS during thegasification conditions is relatively high,and thus the residual carbon with the pore structure destroyed.Therefore,it is not conducive to the formation of porous carbon.