The Study Of Heat Transfer And Kinetics Of Moroccan Oil Shale Pyrolysis

In this paper,I analyzes the basic properties of oil shale and its pyrolysis products in the Taarfaya region of Morocco,including Fischer assay,proximate analysis,heat value,ultimate analysis,composition of retorting gas,et al.The results show that the averaged oil content of Morocco oil shale is 5.50%,the sulfur content is 0.81%.The water content and fixed carbon content are low and ash content is high.The Morocco shale oil has the high value of density,saturate,aromatics,resin,and low value of freezing point,viscosity,flashing point,content of mechanical impurity,and bitumen.The major retorting gases are C₁,C₂,H₂,CO₂ and CO,respectively.The heat value of retorting gas is about 27404 kJ/m³.These basic analysis results can provide an important reference for the comprehensive machining utilization of the Morocco oil shale.The heat transfer and kinetics of oil shale pyrolysis are studied in this paper.This paper focus on the pyrolysis process,which was conducted in a self-designed fixed bed reactor.A one-dimensional spherical transient heat transfer model was established to study heat transfer.Firstly,the traditional analytical method is used to analyze the heat transfer,and then,the finite element analysis?FEA?was used.The internal temperature distribution and heat transfer rules of oil shale were obtained through finite element analysis?FEA?.The results showed that:many temperature gradients were formed from outside to inside of oil shale throughout the whole pyrolysis process,whose range and boundary changed with the pyrolysis process.The temperature difference between the inside and outside of the oil shale particles increased to the maximum and then decreased to the same temperature after the terminal temperature.If the heating rate is fixed,the smaller the particle size of sample,the smaller temperature difference between inside and outside,if the sample particle size is fixed,the smaller the heating rate,the smaller temperature difference between inside and outside.By comparing simulation data and experimental data,we found the temperature distribution obtained by the finite element analysis?FEA?is in good agreement with that obtained by the experiment,and the accuracy is good as well.The model based on finite element analysis in this study shows great performance for simulating the heat transfer of oil shale particles in the pyrolysis process,which would put forward a new idea for the development and utilization of the industrialization of oil shale.Shrinkage particle model was used to analysis the pyrolysis process for the first time,while considering the influence of the internal heat transfer.The kinetics parameters of Morocco oil shale are determined.The calculation results of shrinkage particle model show that the pyrolysis apparent activation energy of large particle Morocco oil shale are about 123.83-126.58 kJ/mol,and the apparent frequency factor are about 2.026×10¹⁴-2.714×10¹⁴ mol/?s·m²?.The shrinkage particle model can simulate the pyrolysis process well.