Study Of The Syngas Production By Co-gasification Of Biomass And Wet Lignite

Lignite,as a low rank coal,is not suitable for direct application as the single source for the production of syngas due to its low calorific value and negative contributions to environment(CO2,NOX,and SOX emission)in pyrolysis or gasification process.Co-pyrolysis and co-gasification of biomass and lignite can solve the above problems to a large extent,improving the conversion efficiency of parent fuel.In this paper,first,thermogravimetric analyzer and fixed bed reactor are applied to research pyrolysis characteristics of biomass and lignite;second,the influence of water content in the wet lignite on synthesis gas index(gas production,H2 / CO,H2 + CO)was investigated;third,the Aspen Plus software was used for the pyrolysis process simulation.The results obtained are summarized as follows:First,TGA was used for the co-pyrolysis of rice husk and lignite analysis.It was found that the higher blending ratio of rice husk brings the lower pyrolysis initial and terminated temperature,the smaller final pyrolysis char solid mass,the lower temperature of maximum weight loss rate and the higher maximum weight loss rate.Most E value of blends for corresponding pyrolysis stage and reaction order is lower than data calculated by additional modal.The E value attains the minimum at the blending ratio was 1:1.Second,in a fixed bed reactor,the effects of final pyrolysis temperature and blending ratio on co-pyrolysis products was investigated.The results showed the gas yield as final pyrolysis as the temperature and blending ratio increase.Char and tar yields show the opposite trend.Volatile and fixed carbon content of char obtained from co-pyrolysis was less than the theoretical value.This shows that synergies can promote the release of volatile and decomposition of solid and char gasification of lignite.Third,the influence of the water content of wet lignite on co-gasification product(gas yield,gas composition,char yield)and the synthesis gas index.The results show that during the low blending ratio,increasing water content of wet lignite leads to increasing gas yield and decreasing char yield.(H2 + CO)value is mainly influenced by final temperature and blending ratio of rice husk.Moisture content improves H2/CO ratio of syngas.Fourth,Aspen Plus simulation software was used to build biomass and coal pyrolysis model to investigate the impact of final pyrolysis temperature and blending ratio on the gas composition.The results showed that the main factors causing the deviation between the simulated and experimental values were the mass and heat transfer process between gas phase and solid and the synergies during the co-gasification.