Research On Combustion Performance Of Biomass In Layer Burner

Biomass as a renewable energy has a broad distribution in china,biomass is renewable and clean and has other advantages. While in China the number of multi-layer burner is large,low efficiency,small output and environmental pollution is serious, researches on biomass combustion of energy for mitigation pressure and environmental protection are significant.In this paper,we choose a 10T/h layer burner as the research object.Three experiments have been selected by biomass industry analysis, calorific value, and dynamic performance, etc. The results show that:volatile content of biomass can reach more than 70%,while heat value and activation energy are low which indicate that ignition performances of biomass are good. Obtained by numerical simulation of the temperature distribution,velocity distribution,pressure distribution and radiation heat load distribution, the results show:the temperature and heat flux of fruit branches are higher than wheat straw and peanut shells, the pressure of wheat straw is higher than fruit branches and peanut shells. Three kinds of biomasses combus completely. Production of CO2 for peanut shells is greater than wheat straw and fruit branches,three biomasses have similar CO2 concentration distribution.Ansys influence on combustion characteristics of biomass for excess air ratio, the results show that:α=1.4, the maximum combustion temperature occurs, heat flux is biggest, but less combustion pressure,α=1.2, combustion is incomplete, the combustion temperature is low, economy is the worst in the case,α=1.4, the radiation heat transfer coefficient can reach 135～245W/m2·K.α=1.2, the radiation heat transfer coefficient is the smallest,which can reach 120～230 W/m2·K.α=1.4, Boltzmann number reaches 0.7～1.7,α=1.3, Boltzmann number reaches 0.6～1.6,α=1.2, Boltzmann number reaches 0.5～1.5.By numerical simulation, comparison of different characteristics for biomass and coal is made,the results show:combustion temperature for coal is higher than biomass,but biomass can combus completely and produce less CO2.Change structure of furnace arch,it is found that increasing the arch angle can enhance disturbance of air flow to improve temperature near the arch,at the same time it can increase the temperature of the furnace and boiler efficiencyThis study can be used to provide a theoretical basis and design guidance as combustion optimization of biomass burning and industrial boiler.