Experimental And Numerical Simulation On Combustion Characteristics Of Furfural Residue And Oil Shale Mixture

Energy and environmental problems are important factors affecting the progress and development of human society.Energy shortage and environmental pollution are very unfavorable for industrial development and residents'production and life.It is of great significance to develop and utilize abundant oil shale and a large number of idle biomass furfural residue resources.There are different interactions in the co-combustion of different fuels.In this paper,for the co-combustion of oil shale and biomass furfural residue,the thermogravimetric analysis,mixing ratio and heating rate are used to analyze the combustion characteristics and dynamics of the mixed sample,and the possible interaction is studied.The response surface analysis is also used to optimize the mixing conditions.Secondly,in the case of the current co-combustion technology is not perfect,it can be used to optimize the mixing conditions Numerical simulation method was used to study the co-combustion of waste biomass furfural residue and oil shale in a large boiler.The results of thermogravimetry show that,oil shale and their mixture can be divided into three stages:moisture precipitation,volatile matter precipitation and combustion,partial volatile matter and fixed carbon burnout.In the combustion stage of volatile matter and fixed carbon,the peak value increases with the increase of the proportion of furfural residue.With the increase of heating rate,the peak value of weight loss rate increases.T₁and T₂ of furfural slag and oil shale mixture decreased with the increase of the proportion of furfural slag,while R_max,R_a,C and CCI of the mixture increased with the increase of the proportion of furfural residue;T₁,T₂,R_max,R_a,C and CCI of the sample increase with the increase of heating rate,which indicates that reasonable furfural residue mixing and higher heating rate are conducive to the combustion of the mixture.It is found that the interaction effect is more obvious in the high temperature range.At the same time,the mass average apparent activation energy(E_m)of furfural residue,oil shale and their mixture was calculated by coats Coats-Redfern integral method.It is found that the combustion activation energy of furfural residue is lower than that of pure furfural residue after mixing with oil shale,indicating that there is interaction between mixed combustion and furfural residue,which can improve the combustion performance of furfural residue and improve its reaction activity;and with the increase of heating rate,the combustion activation energy of mixed combustion decreases.According to the model optimization,the optimal conditions are obtained as follows:the ratio of oil shale mixture16.41%,the heating rate 87.45 K/min,the maximum predicted C is 15.6194×10^-4%·?^-2·min^-1,the maximum CCI is 93.3436×10^-7%²·?^-3·min^-2,and the minimum E_m is17.64164 k J/mol.The results of scanning electron microscopy(SEM),X-ray diffraction(XRD)and infrared spectroscopy(IR)show that the pore structure of furfural residue is developed,while the surface structure of oil shale is more compact.Furfural residue is easier to burn than oil shale.Compared with the single combustion,the mixed combustion SEM has more fine particles,more molten particles and smaller particles.co-combustion of oil shale and furfural residue can solve the problems of ash agglomeration and melting slagging in biomass combustion.Secondly,in the current situation of incomplete co firing technology,the co-firing of waste biomass furfural residue and oil shale can be preliminarily studied by numerical simulation method.In this paper,the physical model of tangentially fired boiler is built by gambit software,and the appropriate model and parameters are determined by Fluent software.The standard k-?model,finite rate model,two-step competitive reaction model,diffusion/kinetics model and P1 model are used.The pressure term is discretized by standard scheme and the other terms are discretized by second order upwind scheme.Fluent software was used to simulate the effects of different oil shale mixing ratios(0,25,50,75,100%)on combustion and pollutant emission in the furnace.The simulation results show that the higher the proportion of furfural residue,the higher the furnace temperature.However,the nitrogen content of oil shale is low,and with the increase of its proportion,the formation of NO_x in furnace combustion decreases.The velocity field,temperature field and the concentration of each component all conform to the distribution law of thermodynamics.The mixed combustion of biomass and oil shale in the original coal-fired industrial boiler has good economic and environmental benefits.The research in this paper combines combustion theory with numerical simulation,which can be used for reference in numerical simulation,experiment and application of biomass and oil shale co-combustion in large boilers.