Research On Biomass Fuel Characteristics And Pollutant Emission Performance Of Blended Coal

With the rapid economic development,energy consumption continues to increase,reserves continue to decline,and environmental pollution becomes increasingly serious.As a kind of renewable clean energy,biomass energy is particularly important to improve the utilization rate of low calorific value biomass fuel.Carrying out research on the characteristics of biomass fuel and its blending performance is of great significance for energy saving and environmental protection.In this paper,the combustion performance of biomass and coal under different mixing ratios is numerically simulated,and the density functional theory is used to analyze the pyrolysis characteristics of biomass.Firstly,a reasonable geometric model and Realizable k-?turbulence model,PDF combustion model,DPM discrete phase model,power/diffusion coke combustion model,double competitive volatilization analysis model and other mathematics were established for the 130 t/h circulating fluidized bed boiler The model,and grid division and evaluation of the computing domain,to determine the number of 284 800 grids can meet the calculation requirements.A numerical simulation study was conducted on the combustion performance of the designed fuel in the furnace,and the flow field,temperature field,flue gas component field and pollutant emission law under hot combustion were analyzed.The error between the average concentration of SO₂ and NO at the exit section of the furnace and the design value were 8.82%and 9.5%,and the calculation errors were within 10%,which verified the rationality of the selected model.Secondly,a numerical simulation study was conducted on the combustion performance of the three biomasses of corn stalk,wheat stalk and sawdust and coal in different blending ratios.It was found that with the increase of the blending ratio of the mixed fuel,the calorific value in the furnace gradually decreased,but the environmental performance improved.The mixed fuel with the same ratio of blending was the pollutant SO₂ emission when the wood chips and coal were mixed.Compared with burning pure coal,blending 15%corn stover,wheat straw and wood chips can reduce SO₂ emissions by 8.3%,3.58%,and 9.42%,and NO emissions by 1.07%,1.99%,and 2.1%,respectively.Finally,a calculation model of biomass pyrolysis characteristics was constructed based on density functional theory?DFT?,based on the pyrolysis of cellulose monomers to generate 5-hydroxymethylfurfural,acetone,and dextran Quantum chemistry research was carried out on three pyrolysis pathways,and the activation energy to be overcome for each pyrolysis reaction pathway was calculated,which were289.66 k J/mol,297.69 k J/mol,and 315.39 k J/mol,respectively.The pyrolysis of different reaction pathways was analyzed.mechanism.It is concluded that the path of pyrolysis of cellulose monomer to 5-hydroxymethylfurfural overcomes the least activation energy and is most likely to occur,and the reaction process to produce L-glucan is least likely to occur.The main products of cellulose monomer pyrolysis are5-hydroxymethylfurfural and H₂O,followed by acetone,glycolaldehyde,and CO.