Chemical Equilibrium Prediction on Release of Na,K,Cl and S-Species during Gasification of Biomass, Soft and Hard Chinese Coal at Elevated Temperature and Pressure by Fact Sage

摘要

The release of alkali species can cause of severe problem of hot corrosion during gasification especially at high temperature and pressure. The direct use of coal may harmful for power plants. The aim of work to obtained comprehensive knowledge prior utilization of coal. Therefore, thermodynamic equilibrium calculations were performed by Fact Sage 5.2 and simulated the gasification environment at elevated temperature and pressure. Four hard and soft Chinese coal such as Yungui (V_(ad)<6.6%), Xiao Tun(V_(ad)<11.1), Datong (V_(ad) <23.18), Ping Zhuan (V_(ad)<31.84),and Saw dust (V_(ad)<68.80) and Saw dust char (V_(ad)<3.39) belongs to anthracite, Sub-bituminous, lignite, biomass and biomass char were selected and releasing order was calculated by plotting mole fraction of each species Vs temperature (1000 to 1400°C) at 1 bar and VS pressure (5 to 15bar) at 1000°C. On the basis of predicted releasing order the H_2S species can be predicted most stable species for gasification at elevated temperature and pressure. The high released amount of SO_2,H_2S, NaCl, KCl and HCl was obtained for YUN, DAT,SAD and SADChar at (1400°C-1000°C) temperature and (15-5bar) pressure. Comparing with high pressure the predicted release of KCl and HCl was observed higher but SO_2, H_2S, and NaCl release was found lower than elevated temperature during combustion process. The above available predicted information is valuable for development of hot gas cleaning technology.