【作者】 杨超；

【导师】 曹发海；

【作者基本信息】 华东理工大学 ， 化学工艺， 2014， 硕士

【摘要】 F-T合成蜡加氢裂解是LTFT合成过程中增加柴油收率,改善油品性质的一个重要工艺,常规颗粒催化剂填充工业固定床反应器,容易受传热、内扩散等传递因素限制影响,本文对微纤结构化催化剂用于F-T合成蜡加氢裂解反应过程强化进行了探索研究。在压力为3.5MPa,氢/蜡比为1000(V),反应温度为290-320℃,WHSV为0.7-2h-1的实验条件范围内,考察了温度和WHSV对Pt/SAB催化剂加氢裂解反应性能的影响,并建立了56#半炼蜡加氢裂解四集总反应动力学模型。该模型模拟优化结果表明,较大的WHSV和较高的反应温度有利于提高柴油收率；反应温度为331.6℃,WHSV为5h-1时,反应转化率为84.61%,柴油收率(C10-C20)为46.68%,液体烃(C5-C20)收率达74.02%。不同粒径Pt/SAB催化剂实验结果表明,当催化剂颗粒大于0.18mm时,内扩散对56#半炼蜡加氢裂解过程存在严重不利影响,使得转化率和柴油选择性降低。恒壁温动态传热实验结果表明,与常规颗粒填充床相比,微纤包结结构化催化剂床层升温速率更快,管外壁与床层中心的温差更小,据此实验表明,微纤包结结构化催化剂能够提高催化床层的导热性能。通过SAB载体高温焙烧实验,证实了微纤包结Pt/SAB结构化催化剂制备工艺中的高温烧结过程会改变SAB载体的微观结构,降低催化剂的比表面积和酸性,从而引起催化剂失活。通过晶种涂覆、二次水热生长技术制备了Pt/ZSM-5/SSMF微纤生长分子筛结构化催化剂。56#半炼蜡加氢裂解反应结果表明,Pt/ZSM-5/SSMF微纤生长分子筛结构化催化剂具有更强的催化反应活性,270℃时反应转化率达80.06%,汽油(C5-C9)收率为53.21%,液体烃(C5-C20)收率达67.23%。更多还原

【Abstract】 Hydrocracking of F-T wax is an important process for improving diesel yield and quality of the products from low-temperature Fischer-Tropsch (LTFT) synthesis process. The industry fixed bed reactors packed with conventional catalysts are easily affected by heat transfer, inner diffusion and other transfer effects. In this paper, the hydrocracking process intensification of F-T wax was investigated over microfibrous structured catalysts.The influences of temperature and WHSV on hydrocracking of semi-refined56#wax with Pt/SAB catalysts were investigated at a pressure of3.5MPa, a temperature range of290-320℃, a WHSV range of0.7-2h-1and a hydrogen to wax ratio of1000(V/V). The four-lumped kinetic model was built based on experimental results. The simulation and optimization results from four-lumped kinetic model show that large WHSV and high reaction temperature can increase the diesel yield. When temperature is330℃and WHSV is5h-1, the conversion ratio of C20+is84.61%, diesel (C10-C20) yield is46.68%and the liquid hydrocarbon (C5-C20) yield is74.02%.The experimental results of Pt/SAB catalysts with different particle size show that inner diffusion has a disadvantageous effect on C20+conversion and makes diesel selectivity decrease when the catalysts particle size is larger than0.18mm. In the heat transfer study with constant wall temperature, the temperature rise of bed packed with microfibrous entrapped catalysts was much faster than conventional Pt/SAB catalysts. Meanwhile, the temperature difference of microfibrous entrapped catalysts was lower than the conventional Pt/SAB catalysts. These results confirmed that the microfibrous entrapped catalysts can enhance the heat transfer of fixed bed reactor. Pt/SAB2catalysts were prepared with carrier SAB calcined at850℃for1h. The results of Pt/SAB2catalysts demonstrate that the high sintering temperature in microfibrous entrapped Pt/SAB catalysts preparation damages the microstructure of SAB carrier, and makes catalysts specific surface area and acidity decrease which causes the deactivation of the microfibrous entrapped Pt/SAB catalysts.Structured microfibrous zeolite catalysts Pt/ZSM-5/SSMF were synthesized by zeolite coatings depositing technique and secondary growth process. The structured microfibrous zeolite catalysts of Pt/ZSM-5/SSMF have good hydrocracking activity. At temperature of270℃, the conversion ratio of semi-refined56#wax was80.06%, the petrol (C5-C9) yield was 53.21%and the liquid hydrocarbon (C5-C20) yield was67.23%.更多还原