Experiment And Simulation Of Decoupling Combustion Of Biomass Pellets

Biomass energy is renewable and has the advantages of low pollution and low emissions.In this paper,the influences of fuel properties and furnace structure on the decoupling combustion of biomass pellets were studied experimentally.In order to obtain the pyrolysis kinetics of biomass pellets,a method called"Hot-thick particle temperature zoning correction"was proposed to modify the pyrolysis kinetics of biomass powder.By simulating the decoupling combustion of biomass pellets,the influences of turbulence model and porous media model were studied in detail.Forest biomass of high calorific value has better combustion performance and lower pollutant emissions than peanut shell biomass.Increasing the length of combustion channel before heat exchange tubes reduces the emission of NO,if only the combustion intensity and temperature in the combustion channel do not decrease significantly.Under the heating condition,the NO emission is less than 100 mg/m³（9%Vol.O₂）.The modified pyrolysis kinetics for biomass pellets characterizes well the actual process of biomass pellets.Comparing with the pyrolysis kinetics for biomass powder,the modified activation energy of pine pellets of 11.11 mm in diameter decreases by 10.44k J/mol,and the index factor decreases by 2 orders of magnitude correspondingly.Integrating the modified pyrolysis kinetics into the simulation of decoupling combustion of biomass pellets,the simulated gas velocity,volatiles,O₂,and CO distribution are reasonable.Moreover,the simulated temperature and component concentration at the chimney outlet are also close to the experimental values.