A Study On The Pyrolysis And Combustion Properties Of Moulded Hybrid Biomass

Biomass fuels have the advantages of wide distribution, low cost, CO2 zero emission, low sulfur content and high oxygen content, easy ignition, high burning rate and easy processing into particles that are easy to store and transport, and attract increasing attention. Biomass have a wide range of variety, different biomass differs in the characteristics of combustion and pyrolysis. Furthermore, the mixing ratio influences directly on the characteristics, which are the bases of production of biomass particles and the efficient combustion. In this thesis, paricles of straw, sawdust, mixure of sawdust and peanut shell from Xuzhou were selected, and their characteristics of combustion and pyrolysis were researched. The biomass combustion theory was introduced to provide foundation for the analysis of biomass particles formation test.The approxinate analysis, ultimate analysis and ash fusion analysis on the combustion of biomass particles, which are straw and sawdust particles with different diameter and the mixture of both, was processed, the results of ash fusion characteristics with varied biomass mixing ratio were obtained. Biomass with varied fineness had different proximate analysis and ultimate analys results, the biomass mixture ash fusion characteristics was better than that of the same single component.Using the thermo-gravimetric-infrared analyzer, straw, sawdust, sawdust and peanut shell mixture(1:1) and straw and sawdust mixture of different mass proportion, under different particle size and heating rate, the pyrolysis and combustion characteristic tested and analysed were conducted under the atmosphere of nitrogen and oxygen. The combustion and pyrolysis TG-DTG curves were obtained, the results show that:(1) straw particles with varied diameters have different precipitation process in pyrolysis process;(2) the higher heating rate the biomass, the wider temperature range in the pyrolysis, with the increase of the heatin g rate, the burnout temperature of rice straw and pine sawdust increase both in a certain degree;(3) adding appropriate amount straw in sawdust contribute to the start and rate of comnustion process. In short, the two component mixture biomass influence e ach other in combustion process.By using single heating rate method, thermal analysis kinetic research on biomass particles TG-DTG curves was conducted, the pyrolysis and combustion kinetic parameter analysis calculation with Coats-Redfern method. It’s shown that, combustion kinetic parameter the activation energies of biomass particles with different mix ratios differ from each other, those have 13 percentage of straw have the maximum activation energy 45.930 k J/mol, in contrast, the activation energy of saw dust reaches the minimum energy 21.137 k J/mol. In addition the activation energy increases with respect to the ratio of straws in the biomass particle in the range of above 25%.