Experimental Study On Co-pyrolysis Of Biomass And Coal

Biomass energy is a clean renewable energy resource. With the increasingly tight supply of fossil fuels and severe environmental pollution, biomass energy has been attached to great attention around the world. The co-pyrolysis behavior of biomass and coal mixture was studied by thermogravimetric (TG) analysis coupled with Fourier Transform Infrared Spectroscopy (FTIR). The coal samples used in experiment are long- flame coal (LC) and meager coal (MC),and the biomass experimental samples are corn straw (CS) and sawdust (SD).The pyrolysis performance of single coal and biomass were examined,and the influence of heating rate on pyrolysis process and release of gaseous products were analyzed. The co-pyrolysis characteristics of biomass and coal was discussed, as well as the kinetic model of co-pyrolysis was erected and the kinetic parameters were obtained. On the basis of research that the mechanism and release of gaseous products of biomass and coal co-pyrolysis was investigated at different blend- ing ratio of biomass in mixture (BR),temperature range and various combinations of biomass and coal, the synergetic effets during biomass and coal co-pyrolysis were dis- cussed.The experimental results showed that the DTG peaks of devolatilization becomes wider with the increase of the heating rate. The Tbmax and Tcmax which DTG peak temperature of biomass and coal co- pyrolysis was decreased with the increase of BR at the heating rate of 50℃/min. It could be deduced that the main pyrolysis temperature range of biomass and coal can be overlapped partly at high heating rate. In the overlapped temperature range, the free-radical generated from biomass pyrolysis might function as coal hydropyrolysis with the result that the synergetic effects might be existed during biomass and coal co-pyrolysisCompare with co-pyrolysis of biomass and LC, biomass had more effect on copyrolysis of biomass and MC. The higher BR wasn't benefit to increase the gaseous products yield in the co-pyrolysis of biomass and LC, but it was favor of the yield in the co-pyrolysis of biomass and MC. Compared with the theoretical and measured values of CH4 and CO yield resulted from coal and Biomass co-pyrolysis at different BR.It can be found that the measured values of CH4 yield was biger than the theoretical value(except SD&LC co-pyrolysis at 500℃) and the measured values of CO yield was smaller than theoretical value(except Bio.&MC co-pyrolysis at 500℃) ,and it indicated that the difference between theoretical and measured values were related with BR and species of coal or biomass.The change of component and content of gaseous products indicated that the synergetic effects may be existed during co-pyrolysis.With the increasing of BR and co-pyrolysis temperature, yield of CH4 and CO were increased. The yield of CH4 and CO were effected by BR which was more obvious than co-pyrolysis temperature during coal and SD co-pyrolysis; The yield of CH4 and CO were effected by co-pyrolysis temperature which was more obvious than BR during the conditions of LC and CS co-pyrolysis; During MC and CS co-pyrolysis, co-pyrolysis temperature had more obvious influence on yield of CO than BR, but less obvious influence on yield of CH4. So the synergetic effects during co-pyrolysis were relation to BR, Terminal temperature and species of coal and biomass.