【作者】 田立达；

【导师】 沈本贤；

【作者基本信息】 华东理工大学 ， 化学工艺， 2012， 博士

【摘要】 对延迟焦化工艺进行优化是应对原油重质化、劣质化,提高重质油加工水平的重要方法。采用计算机集总动力学模型进行工艺优化方便可靠,是工艺优化的有效途径。结构导向集总新方法以新的理念实现分子尺度的集总。用其构建动力学模型将提升模型的适用性和实用性。论文首先对延迟焦化原料油分子组成进行了模拟。在对原有结构向量进行适当修改的基础上,提出了代表延迟焦化原料油分子组成的92种单核种子分子和46种多核种子分子,共7004种分子集总。结合分子集总数据库和优化算法,论文确定了模拟计算重质油分子组成的新方法。该方法较好反映了重质油分子集总组成和含量。由此计算得到的重质油宏观性质和实际值接近。其次,论文采用92条反应规则描述延迟焦化反应行为,利用计算机软件和回归算法理论计算反应速率常数,以求解动力学微分方程组的形式构建了一个延迟焦化结构导向集总模型,并编写了该模型的工艺包和用户操作界面。该模型能较好反映焦化过程的真实分子反应行为,具有较好原料适应性和产物分布预测功能。为确保模型验证和后续计算的合理性,论文对DVS-JHJL-1130型延迟焦化实验室小试装置进行了可靠性验证。通过小试试验数据和中石化高桥分公司二套焦化装置的工业统计数据比对,证实了该小试试验装置的可靠性。在此基础上,论文利用该小试装置数据和工业统计数据验证了所建立模型在不同条件下对不同原料的预测准确性。结果表明,模型预测结果和小试试验结果以及工业统计数据均吻合良好,相对误差不超过10%。随后,论文利用所建立的模型分析了原料性质对延迟焦化液体产物收率的影响,并进行了延迟焦化原料组成调优。在480℃,0.15MPa,0.3循环比条件下,论文对不同原料渣油相互掺炼进行了结构导向集总模型计算和小试试验。比对结果表明：工业操作条件下,2#和4#原料渣油按7：3(质量)掺炼,液体产物收率相比两种原料渣油单独焦化之和提高1.22%。接着,论文利用所建立的模型考察了回收废道路沥青作为延迟焦化原料的可能性。结果表明：回收废道路沥青含有饱和分和芳香分,而且其中胶质沥青质具有可发生裂解反应的大长链,可以作为延迟焦化掺炼原料。但是其直接焦化的生焦率高达70%,易堵,难以满足延迟焦化工艺要求,因而需要和渣油掺炼。通过结构导向集总模型计算渣油掺炼回收废道路沥青共焦化的结果后发现：焦化液体产物收率随着掺入量的增加而减少,气体和焦炭收率增大；焦炭收率随着共焦化反应温度和反应时间的提升而下降,气体和液体收率上升。为避免装置堵塞和操作安全,论文认为利用延迟焦化实验室小试装置开展渣油掺炼回收废道路沥青共焦化实验时,回收废沥青掺入量的上限是20%(质量),共焦化反应温度和反应时间也需要进行一定控制。最后,论文在470℃,0.15MPa,零循环比条件下利用实验室小试装置开展了渣油掺炼回收废道路沥青共焦化实验。回收废道路沥青采用旋转薄膜烘箱试验法模拟,掺入量为20%。渣油选用4#原料渣油。比较掺炼前后的产物分布发现：和全渣油结果乘以80%的数据相比,掺炼后增产气体2.3%,增产液体2.91%,增产焦炭14.79%。经济效益估算表明,掺炼废沥青共焦化有利于环境保护和经济效益。掺炼产物中,焦化气体烯烃含量增加。焦化汽柴油性质和掺炼前相近。焦化蜡油和石油焦的品质有所下降。焦化蜡油中重组分、残炭、硫、氮和金属含量增多。石油焦灰分和硫含量增加。掺炼后的焦化蜡油仍符合催化裂化进料标准,掺炼后石油焦从三A级变为三B级,但仍能作为燃料处理。这既拓宽了延迟焦化原料,又为回收废道路沥青如何合理利用开辟了一条值得尝试的新途径。更多还原

【Abstract】 Optimization of delayed coking is a main method to meet the problem that crude oil becoming heavier and worse and increase the heavy oil processing level. Optimizing with lumped kinetic model is convenient and reliable; it is an effective way to process optimization. Structure Oriented Lumping (SOL) new method achieved molecular level lumping with new concept. Build kinetic model with SOL method will increase applicability and commodity of the model largely.Firstly, the molecular composition of delayed coking feedstock has been simulated. After doing some modifications to original structure vectors,92 kinds of single-core and 46 kinds of multi-core seed molecules, totally 7004 kinds of molecular lumps were proposed to represent the molecular composition of delayed coking feedstock. Combining with optimizing algorithm and molecular lump database, the paper proposed a new method to calculate the molecular composition of heavy oil. The method reflected the composition and contents of molecular lumps of heavy oil. The calculation bulk properties of simulated heavy oil agreed with true values well.Secondly, paper used 92 kinds of reaction rules to describe the reaction behaviors of delayed coking, used computer software and regress algorithm to estimate the reaction rate constants of delayed coking, built a delayed coking SOL model with the function of predicting product distribution as the form of solving kinetic simultaneous differential equations, and compiled the interface and processing package. The model reflected real molecular reaction behaviors well, and had a good material flexibility and product distribution predict functions. To ensure the rationality of model test and next calculation, paper checked the reliability of DVS-JHJL-1130 delayed coking experimental device. The reliability of delayed coking experimental device was proved by the comparison of experimental data and industrial statistics data from Sinopec. Based on this, paper checked the reliability of the proposed model on different feedstock under different operating conditions with experimental data and industrial data. The results shows that, model predict results agreed with experimental results and industrial average results well. The relative errors are less than 10%.Thirdly, the effects of feedstock properties on liquid yields of delayed coking were analyzed by the proposed model, and do delayed coking materials composition optimization. Under the operating condition of 480℃,0.15MPa and 0.3 recycle ratio, model calculation and experiments on different material residues mix have been done. The results show that:mix 2# with 4# residue (7:3) will increase liquid yields 1.22% than sum of them coking independent under industrial operating conditions.Fourth, paper analyzed the possibility of recycling waste road asphalt as delayed coking new feedstock with the proposed model. The results shows that:recycling waste asphalt has saturates and aromatics, and the long side chains in resins and asphaltenes could also be break in delayed coking process, so it could be a new mix feedstock of delayed coking. However, coke yields were high to 70% when recycling waste asphalt as delayed coking feedstock directly. It is hard to satisfy the requirements of delayed coking and easy to block up. So, it is better to mix with residues. After calculating the results of residue and recycling waste asphalt co-coking with the SOL model, liquid yields of co-coking were decreased with the increasing of asphalt mixing ratio while gas and coke increasing, coke yields of co-coking were decreased with the increasing of reaction temperature and time while gas and liquid yields increasing. In view of device blocking and safety, the upper limit of asphalt mixing ratio was 20% and temperature and reaction time of co-coking also needed to be limited when do residue and asphalt co-coking experiments on the delayed coking experimental device.Lastly, experiments of residue and asphalt co-coking were carried out on the experimental device under the conditions of 470℃,0.15MPa and 0 recycle ratio. Recycling waste road asphalt was simulated by RTFOT experiments. Asphalt mixing ratio was 20%. Comparing with 80% residue coking, gas, liquid and coke yields of after-mixing were increased 2.3%,2.91% and 14.79% respectively. Economic benefit estimate shows that:residue and asphalt co-coking is helpful for environmental protection and economic benefit. After mixing, olefins in gas were increased. The quality of gasoline and diesel were similar. The quality of wax oil and coke were decreased. Carbon residue, heavy components, sulfur, nitrogen and metal content in wax oil were increased; ash and sulfur content in coke were increased. The wax oil from after-mixing was still accord with the standard of catalytic cracking feedstock. The coke turned to 3B from 3A, but it still could be used as fuel. This developed a new way to deal with the problem how to used recycling waste asphalt well and extend the material of delayed coking.更多还原