焦炉气加氢催化剂及净化工艺的开发

介绍了适合于焦炉气加氢催化剂及净化工艺的研究实验结果,实验表明,JT-1及JT-8型加氢催化剂均可适用于含高浓度CO和CO2气氛下原料气的加氢净化,且净化度高,副反应小,并满足以焦炉气为原料的甲醇厂的原料净化要求,可将原料气中硫化物脱除至总硫体积分数<0.1×10-6。     

Modular handover algorithm for 5G HetNets with comprehensive load index

Most existing handover decision system (HDS) designs are monolithic, resulting in high computational cost and unbalance of overall network. A novel modular handover algorithm with a comprehensive load index for the 5th generation (5G) heterogeneous networks (HetNets) is proposed. In this paper, the handover parameters, serving as the basis for handover, are classified into network's quality of service (QoS) module, user preference (UP) module and degree of satisfaction (DS) module according to the new modular HDS design. To optimize switching process, the comprehensive network load index is deduced by using triangle module fusion operator. With respect to the existing handover algorithm, the simulation results indicate that the proposed algorithm can reduce the handover frequency and maintain user satisfaction at a higher level. Meanwhile, due to its block calculation, it can bring about 1.4 s execution time improvement.     

制备条件对MoO_3/γ-Al_2O_3结构的影响及ZnO改性作用的LRS研究

当MoO_3含量低于单层分散容量时,MoO_3/γ-Al_2O_3喇曼谱图上两个最突出的峰是～950cm~(-1)的宽峰和876cm~(-1)的较尖锐峰。前者代表“二维聚铝酸”(其中的铝主要是八面体配位的),是加氢脱硫(HDS)等活性中心的前身;后者代表孤立的、四面体配位的钿物种,在加氢脱硫反应中没有活性。用定性和定量的方法系统研究了浸渍液的pH值、焙烧温度、时间、MoO_3总含量等因素对MoO_3/γ-Al_2O_3中两种钼物种相对含量的影响。探讨了在制备过程中减少这种四面体配位钼物种相对含量的方法。指出添加ZnO,使γ-Al_2O_3变成缺锌铝酸锌可以在一定程度上抑制此种非活性钼物种的生成,从而达到提高催化剂活性的目的。     

焦炉煤气加氢脱硫催化剂的试验及应用

焦炉煤气生产甲醇的技术关键之一是其深度净化技术,有机硫的加氢净化精度是转化催化剂和甲醇催化剂长周期稳定运行的关键。介绍了焦炉煤气加氢净化催化剂的组成、使用条件及批试验结果,以及研制的JT-8和JT-1型焦炉煤气两级加氢催化剂的工业应用结果,可使出口总硫小于0.1×10-6,达到工艺设计要求,具有较好的社会效益和经济效益。     

Reactivity of several olefins in the HDS of full boiling range FCC gasoline over PtPd/USY

Reactivity of C₄–C₆ olefins during the selective HDS of a full boiling range FCC gasoline over PtPd/USY catalyst was studied under various process conditions. Effect of the structure and carbon number of olefins on their conversion is discussed. It was found that the rate of hydrogenation decreases with the carbon number of linear olefins. Terminal olefins are readily converted to internal ones by double bond shift to approach the equilibrium composition of olefin isomers.     

Study of accelerated deactivation of hydrotreating catalysts by vanadium impregnation method

The main causes of catalysts deactivation for hydrotreating are coking and metals deposition. In this present work, accelerated deactivation of hydrotreating catalysts was studied. In this respect, vanadium which is deposited with nickel during hydrotreating reaction was impregnated into the fresh hydrotreating catalyst. Different percentage of vanadium was impregnated and their hydrodemetalization (HDM) and hydrodesulfurization (HDS) activities were studied in bench-scale reactor of heavy crude oil. Accelerated deactivations for both HDM and HDS were observed on vanadium impregnated catalysts. The rate of HDS deactivation was faster than that of HDM reaction. The rapid deactivation of HDS may be due to the coverage of active sites by impregnated vanadium atom. The deactivation is slower when the V loading is low; but above 10 wt% loading a rapid deactivation is observed. A comparison of deactivation is made in between normal deactivation and the deactivation by vanadium impregnation. It was found that deactivation by vanadium impregnation is lower than that of normal deactivation. It suggests that at initial stage the formation of coke causes deactivation of the catalyst whereas at later stage when metals sulfides deposition is quite high, these sulfides take part in deactivation.     

Effect of preparation methods and content of phosphorus on hydrotreating activity

The effect of phosphorus content and preparation methods is studied in this present investigation. Three different methods are employed for preparation of catalysts. The catalysts are characterized by pore size distribution, X-ray diffractogram and temperature programmed reduction. Thiophene hydrodesulfurization (HDS), cumene hydrocracking (HC), gas oil HDS and Maya heavy crude HDS and hydrodemetallization (HDM) activities are performed. It is found that specific surface area gradually decreases with P loading. The addition of phosphorus increases the formation of polymolybdate species which are more active for hydrotreating reaction. It is also observed that reducibility of these species also increases with P loading. However, at higher P loading the crystalline MoO₃ is formed at the expense of these multilayer polymeric molybdates. The increment in the activity is more in the catalyst prepared by co-impregnation method. The activity increases with P loading up to 1 wt% P content. At higher loading the activity decreases. It is also noted that P inhibits coke formation on the catalyst during hydrotreating of heavy crude oil. Phosphorus can also modify the Brønsted acidity of the catalyst and hence cumene hydrocracking activity slightly increases.     

Heavy crude oil hydroprocessing: A zeolite-based CoMo catalyst and its spent catalyst characterization

This study presents an effect of zeolite with alumina as a support for heavy oil hydroprocessing. The high surface area, moderately acidic meso- and macro-porous support was prepared with the mixing of alumina and ultra-stable Y zeolite (US-Y). The micro-structure and the composition of the zeolite crystals formed in the bulk of the alumina were examined by scanning electron microscopy with energy dispersive X-ray analysis (SEM-EDX), and there were two main crystal phases homogeneously distributed in it. A CoMo sulfide supported catalyst is evaluated for hydroconversion of Maya heavy crude oil at moderate pressure conditions. The combination of ultra-stable zeolite and alumina is able to produce bi-modal type of pores in the catalyst which may contribute to a better combination of hydrodesulfurization (HDS), hydrodemetallization (HDM) and the selective cracking of asphaltene over the acidic catalysts. The characterization of spent catalysts can help as an assistance for the selection of optimum catalyst properties along with the reactor bed length and type of catalyst pore in each bed. The strapping reaction condition indicated that the acidic catalyst for heavy oil can be used more effectively at lower temperature. An increase in temperature showed that the HDM and hydrogenation of asphaltenes (HDAs) conversions are more affected than HDS and HDN. These results indicate occurrence of a thermal cracking of complex molecules like asphaltene and metal porphyrins, which is confirmed by the gaseous selectivity of the hydrocarbons.     

油品深度加氢脱硫催化研究进展

汽油深度脱硫的关键是在脱硫同时避免辛烷值的下降和汽油收率的损失;柴油深度脱硫的关键是对反应活性最低的4,6-二甲基苯并噻吩类化合物中硫原子的脱除,并克服原料中多环芳烃和含氮物以及产物中H2S对脱硫效果的抑制作用.本文概述了汽油和柴油深度脱硫催化剂在工业应用方面的研究进展,综述了加氢脱硫催化剂基础研究方面的最新动态;强调了在分子和原子水平上认识加氢脱硫催化剂微观结构和反应机理对研发超高活性及选择性深度脱硫催化剂的指导作用.     

TiO2复合氧化物的制备及其在加氢脱硫中的应用

对TiO₂、TiO₂-Al₂O₃、TiO₂-SiO₂和TiO₂-ZrO₂载体的制备技术及其在加氢脱硫中的应用进行了综述。研究表明，以TiO₂调变的Al₂O₃、SiO₂和ZrO₂载体能影响MoO₃与Al₂O₃、MoO₃与SiO₂及MoO₃与ZrO₂之间的相互作用，改善MoO₃在载体表面的分散，促进其还原，有利于提高催化剂表面活性组分的数量，提高催化剂的加氢脱硫活性。