Experimental Study On Mechanism Of Co-gasification Of Biomass And Coal

Biomass has been the hot issue of energy study because it is renewable and environment friendly—there would be no carbon dioxide emission during its utilization. Biomass gasification is the main technology of its utilization.On the basis of biomass gasification,co-gasification of biomass and coal is discussed in this thesis,along with its allied experiment.Elaborations on biomass gasification technology are presented in the thesis.Based on existing coal gasification technology,the research on co-gasification of biomass and coal is conducted,and advantages that biomass and coal co-gasification in earlier stage are found as follows:①Coal can not only generate heat but also carry heat in fluidized bed;it can substitute inert particles and make the fluidized bed run steadily.②It is easier to set up high-temperature in fluidized bed by using co-gasification of biomass and coal and can accelerate the tar cracking with steam as gasifying agent.③It can improve the caloric value of the gas and conversion ratio of the carbon.Based on the above test results,the main task of the mechanism research on co-gasification of biomass and coal includes the following several respect.The cold-state experimental study on biomass and coal in fluidized bed was carried out:The fluidization behaviors of three kinds of different biomass(corn core,sawdust and rice husk)and the mixtures of these bio-fuels with inert particles(cinder and sand)were investigated experimentally in a fluidized bed.Test result shows that the fluidization behaviors of mixtures are easier to fluidize than the single bio-fuels,and adding a small amout of cinder and sand as inert particles may tangibly improve its fluidization,with inert particles portion at least 20%higher than the mixture. Based on the equation of Ergun and theoretical analysis,empirical formulas for the calculation of minimum fluidization velocity of the binary mixture particle system were obtained,and the error is around less than 10%.According to two different kinds of ash formation of binary mixture of biomass and coal,ash melting test and X ray diffraction (XRD)about binary mixture are tested.The test finds that ash melting temperature and ash composition of binary mixture lie between that of single coal and biomass.With the qualities of coal or its ash increasing,the ash melting temperature and ash composition of binary mixture gradually grow to that of coal ash.At last,on the basis of traditional judge index of coal ash slagging,fuzzy synthetic evaluation is provided to predict the ash slagging behavior of binary mixture.Research work of this paper may offer a basis and may of some reference value to co-gasification technology of biomass and coal in the future.