The modified model for predicting the products distribution in pyrolysis of biomass

摘要

Pyrolysis is known as one of the promising thermochemical conversion routes in producing solid (charcoal),liquid (tar) and gaseous products.In the present study,deposition coefficient,defined as the fraction of volatile and gases deposited on the char due to the secondary reaction,is introduced to modify the kinetics model in literatures.The effects of heating rates,heating temperatures and deposition coefficients on pyrolysis products distribution under non-isothermal and isothermal conditions are discussed.The investigation based on the modified model shows that the deposition coefficient affects the secondary reaction products distribution significantly.When the deposition coefficient increases,the generation rate and the concentration of char increase and the volatile and gases in secondary reaction decrease.The results indicate that primary reaction plays a dominant role in volatile and gases generation and secondary reaction plays a dominant role in char generation.The work in this paper provides useful information for optimal design of biomass gasifiers and reactors.