A Study On Lumped Kinetic Model Of Coal Tar Hydcracking Process

Coal tar is an inevitable byproduct produced in the coal pyrogenation process. Inrecent years, with the rapid development of China’s economic and coal chemicalindustry, coal tar production output increased quickly. Meanwhile, as the growthdemand for world oil and the climbing prices, production of clean fuel oil fromlow-temperature, as a new alternative energy sources, is strategic importance to ensureenergy security.During the research on the coal tar hydrogenation process, the calculation of akinetic model is necessary to acquire a good understanding of the hydrogenation ofcoal tar, particularly in order to design and simulate a reactor, to predict reactionbehavior, and to optimize operating conditions. For this kind of complex reactionsystem, lumping approach is usually used to study their dynamics at home and abroad.Therefore, in this thesis, based on small scale experimental apparatus measured datafrom the low-temperature coal tar hydrogenation process, coal tar hydrogenationlumped reaction kinetics were studied.The contents for the research include: A new5-lump kinetic model （coal tar,gasoline, diesel, gas, coke） of coal tar hydrocracking was proposed based on thespecial of coal tar and analysis of experimental product results. According to thedivision of lumped, five-lump reaction network was constructed and a lumped kineticmodel was also established.Using the MATLAB software programming regression ofthe kinetic model parameters. The proposed model was also validated. Comparisonsbetween the experimental data and predictions using the lumping kinetic modelshowed good agreement. with the relative error is lower5%. Thus the establishedmodel is suitable for the coal tar system.On the basis of the results of five-lump kinetic model, a new eight-lump kineticmodel containing19kinetic constants is proposed to describe coal tar hydrogenation. The model were not only fully considered the model establishment and assumptions,but also take into account the experimental conditions and the actual situation. Theresults show that the model is more suitable to the calculation of coal tarhydrogenation. The effect of temperature, space velocity, hydrogen/oil ratio, and initialhydrogen pressure on hydrogenation performance is also discussed. The resultsindicate that the hydrogenation of coal tar should be conducted at a low space velocityof0.4h^-1, hydrogen/oil ratio of1600, initial hydrogen pressure of8MPa, andtemperature of380oC in order to reach the optimal yields of products, which provide afeasibility of reference for the next pilot plant operation as well as the smooth progressof industrialization.