Process and Catalyst Needs for Hydrodenitrogenation

During the last decade there has been increased interest in the production of synthetic fuels and chemicals feedstocks from coal and oil shale due to declining petroleum reserves. Table 1 gives the projected gasoline to mid-distillate ratio through the year 2000 and beyond; the shift is away from high-octane fuels requiring a relatively high aromatics content and a relatively low hydrogen content to highly paraffin-based fuels having a high hydrogen content. Figure 1 shows the projected United States energy supply and demand through the year 1990 [2], Current petroleum production in the contiguous United States is about 9 million bbl/day and has declined at a rate of about 0.5 million bbl/day per year for a number of years. Alaskan oil will arrest this decline in production briefly but will not make up for even the loss in the rate of petroleum production incurred in the contiguous 48 states during the last 5 years. In all probability, declining production from current oil fields will not be offset by further new discoveries, and thus the United States will become increasingly dependent on foreign oil. Further, petroleum feedstocks are becoming harder to process as crude quality decreases, and as it becomes more and more necessary to process the bottom of the barrel. Declining oil supply in the face of increasing demand will ultimately require that some of the projected gap be made up with synthetics made from coal and oil shale. Such synthetic feedstocks and heavier petroleum fractions contain higher concentrations of nitrogen than light petroleum stocks, are decidedly more difficult to process, and will place increasing demands on hydroprocessing catalysts and processes.     

渣油加氢脱氮催化剂的研究

本研究用简便的混捏法制备高活性的渣油加氢脱氮催化剂,制备技术的关键是采用合适的扩孔剂、助剂和焙烧温度,以克服混捏法所固有的缺点。     

WP/γ-Al2O3催化剂的制备及加氢脱氮性能

采用程序升温、高纯氢气还原无定形磷钨酸盐的方法制备了活性组分为磷化钨的WP／γ-A1203催化剂，考察了催化剂对吡啶加氢脱氮(HDN)反应的催化活性。结果表明，先混合后还原方法制备的WP／γ～Al2O3催化剂WP2更有利于活性组分在载体表面的分散，且稳定性比较好。该催化剂具有较好的加氢脱氮性能，340℃时吡啶加氢脱氮率为95．4％。噻吩对催化剂WP2的HDN活性有较大影响。     

Hydrodenitrogenation of Quinoline Over a Dispersed Molybdenium Catalyst Using in situ Hydrogen

Hydrodenitrogenation (HDN) of quinoline using a Mo-based dispersed catalyst was studied in a batch reactor using H₂ generated in situ via the water gas shift reaction. In situ H₂ was found to be more active for HDN than externally supplied H₂. Both water and H₂S have an effect on HDN.     

Hydrodenitrogenation Catalysis

Catalytic hydrodenitrogenation (HDN) is a process in which organonitrogen compounds are removed from hydrocarbon feedstocks to produce processible, stable, and environmentally acceptable liquid fuels and lube base stocks. When coupled with hydrodesul-furization (HDS), this process is commonly referred to as “hydro-treating,” which is an integral part of oil refining. While it has long been recognized that HDN is more difficult than HDS, the former has historically been of little concern to the refiners because of the comparatively small quantities of nitrogen compounds present in conventional petroleum stocks. This situation, however, will certainly change because of the growing need to process heavy and low-quality stocks, and the anticipated need to upgrade syncrudes, both of which are rich in highly refractory nitrogen compounds. At present, conventional HDS catalyst technology is adapted for HDN, despite the fact that it is not ideally suited for nitrogen removal. In recent years there has been considerable interest in the development of more effective HDN catalysts, as witnessed by the rapidly expanding patent literature in this area.     

Hydrodenitrogenation of Petroleum

A high level of hydrodenitrogenation (HDN) is required to achieve a desirable conversion of other hydroprocessing reactions. This results from a strong adsorption of nitrogen‐containing compounds on catalytic sites that slows down the hydrogen activation process and hinders the adsorption of other reactants. Studies on model compounds and real feeds indicate that less than 50 ppm of nitrogen in the feed can poison catalytic sites. Kinetic studies determined adsorption constants of various nitrogen‐containing compounds and concluded that at least four different catalytic sites are required to interpret experimental observations in contrast with a dual site site?concept, which only considered two sites. The advancements in experimental techniques allowed identification of products formed during very early stages of hydrodenitrogenation. These results confirmed that the removal of the amino group from saturated amines, as the last step in hydrodenitrogenation, is governed by the type of carbon to which the amino group is attached rather than the number of hydrogen atoms attached to carbon in α and β position to nitrogen

Performance of conventional Co(Ni)Mo(W)/Al₂O₃ catalysts during hydrodenitrogenation was enhanced by combination with various additives and by replacing the traditionally used γ‐Al₂O₃ support with novel supports. Catalytic functionalities could be modified by using different precursors of active metals and varying conditions during preparation. Progress has been made in the development of catalysts possessing a high selectivity for hydrodenitrogenation. In this case, the nonconventional catalysts based on the carbides and nitrides of transition metals exhibited high activity and selectivity. Noble metal sulfides alone or supported on different supports were active for HDN as well. Feedstocks used for catalyst evaluation included model compounds and mixtures of model compounds as well as real feeds. The challenges in the development of catalysts for hydrodenitrogenation of heavy feeds containing asphaltenes and metals have been identified.     

Hydrodenitrogenation of isoquinoline

To determine the formation and reactivity of addition compounds produced during hydrodenitrogenation (HDN), we investigated the HDN of isoquinoline for a sulfided Ni–Mo/Al₂O₃ catalyst operated under a hydrogen pressure of 12 MPa (cold charge) in the temperature range 300–375°C. The reaction products were classified into five groups of compounds:

1. hydrogenated derivatives of isoquinoline (tetrahydroisoquinolines, decahydroisoquinolines, and their isomers);

2. nitrogen-containing ring-opened products (1-amino-2-(2-methylphenyl)ethane and 1-amino-1-(2-ethylphenyl)methane);

3. denitrogenated products (1-ethyl-2-methylbenzene, 1-ethyl-2-methylcyclohexane, and their isomers);

4. addition products (hydrocarbons with molecular weights of 238, 244, and 250 and nitrogen-containing compounds with molecular weights of 249, 251, and 257); and

5. cracked products (toluene, ethylbenzene, dimethylbenzenes, and their hydrogenated derivatives).

Most of the nitrogen-containing addition compounds appear to be substituted on the nitrogen atom. The HDN of isoquinoline was more than 10 times faster than the HDN of quinoline, whereas the hydrogenation of isoquinoline was difficult compared to the hydrogenation of quinoline. The reaction network for the HDN of isoquinoline is also presented.     

聚乙烯工艺及催化剂新进展

综述国内外聚乙烯生产工艺及其催化剂的最新进展，对国内如何开展这方面的工作提出了几点建议。     

工业NiW/Al2O3催化剂上喹啉的加氢脱氮宏观动力学

以喹啉为含氮模型化合物,在高压滴流床反应装置中考察了工业NiW/Al2O3催化剂RN-10上的加氢脱氮动力学规律,研究了反应温度330～420℃、氢分压1.2～5.2MPa、氢油比200～800(v/v)、重量空速(WHSV)20～70 h-1等反应条件对喹啉的加氢脱氮反应结果的影响.结果表明,反应温度对喹啉的脱氮率影响较大,提高反应温度可有效提高喹啉的脱氮率;同时,氢分压也是喹啉加氢脱氮的一个重要的影响因素,但是,当氢分压和氢油比较大时,氢分压和氢油比的变化对喹啉的脱氮率基本无影响.采用修正的n(n＜1)级反应动力学模型对实验数据进行拟合,求得了喹啉加氢脱氮反应的表观活化能为180.4 kJ·mol-1.经检验,模型计算结果与实验结果能较好地吻合.     

甲醇制丙烯(MTP)工艺过程中催化剂的再生过程分析

大连化物所的DMTO(甲醇制烯烃)工艺及鲁奇公司的MTP(甲醇制丙烯)工艺是目前世界上两种已经实现了商业化的甲醇制低碳烯烃技术,两种工艺均采用沸石催化剂。文章从工艺过程出发,介绍了MTP(甲醇制丙烯)工艺技术中所采用的沸石基甲醇制丙烯催化剂的再生操作过程。     

预转化工艺与高性能预转化催化剂

由于充分认识到预转化给合成氨行业带来的投资和能耗的效益 ,现在合成气生产厂已广泛采用预转化工艺。本文着眼于当前预转化市场的背景并对通过使用最新一代CRG转化催化剂产生更好的效益进行评价。第一代CRG催化剂是英国气体委员会在 60年代初研制出来的 ,当时的目的是为了寻找一条以资源丰富的液体蒸馏产物代替主导原料煤生产合成气的途径 ,KvaernerProcessTecknology(KPT) ,当时称为Powergas公司 ,是第 1批获得独创的CRG工艺专利许可证的公司之一 ,并且一直在工业应用中处于主导地位。 1 997年KPT从BritishGas获得了经营CRG技术…     

中低低流程变换装置催化剂的应用

介绍了中低低变换装置工艺流程;分析了该装置催化剂使用寿命偏低的原因;简述了中变采用B116低铬型和低变采用B303Q钴钼系催化剂的装填方案、升温还原和升温硫化过程以及生产运行情况。     

加氢催化剂预硫化的影响因素

加氢催化剂的预硫化是提高催化剂活性、优化加氧催化操作,获得理想经济效益的关键技术之一。为获得理想的预硫化效果,必须严格控制各阶段的反应条件。介绍了加氢催化剂预硫化的反应原理,探讨了在预硫化过程中影响催化剂预硫化效果的因素。预硫化操作中,温度是最敏感的因素之一。     

加氢催化剂预硫化的影响因素

加氢催化剂的预硫化是提高催化剂活性，优化加氢催化操作，获得理想经济效益的关键技术之一。为获得理想的预硫化效果，必须严格控制各阶段的反应条件。文章介绍了加氢催化剂预硫化的反应原理，探讨了在预硫化过程中影响催化剂预硫化效果的因素。预硫化操作中，温度是最敏感的因素之一。     

蒽醌法生产双氧水钯触媒与镍触媒之比较

对蒽醌法生产双氧水采用不同的触煤的差异进行比较和分析,指出以钯触毁取代镍触煤已势在必行。     

甲醇制丙烯工艺催化剂的汽蒸过程分析

甲醇制丙烯工艺采用ZSM-5型催化剂,为优化其丙烯选择性,在使用之前需要进行汽蒸。介绍了系统的氮气预热流程和工艺蒸汽预热流程;从工艺过程出发,简述了催化剂的汽蒸操作过程。     

生产清洁汽油的新型GOR系列裂化催化剂及其工艺技术

为解决原油深加工带来的催化裂化原料重质化与生产环境友好清洁汽油燃料的矛盾，石油化工科学研究院开发出新型降低催化汽油烯烃含量的GOR系列催化剂及其工艺技术，并成功应用在多套重油催化裂化装置上。实践证明：它能显著降低汽油中烯烃含量，保证汽油RON基因不变，改善安定性能，同时具有较强的重油转化能力、较好的产品选择性和较强的抗重金属污染能力等特点。     

水煤气无变换脱硫工艺中水解催化剂的选择和应用

我公司200 kt/a焦炉煤气配水煤气制甲醇装置的水煤气系统采用无变换精脱硫工艺,结合实际应用经验,对各种类型脱硫水解催化剂的选择和应用进行了总结和论述,对已采用或者拟采用同类型工艺的企业具有一定的参考价值。     

合成氨催化剂中毒原因分析和工艺处理方法

分析了凯洛格型氨合成塔催化剂中毒的原因,提出了预防催化剂中毒的技术措施。例举了催化剂水中毒和油中毒的典型案例,介绍了其工艺处理方法和操作实施过程。     

芳烃歧化工艺及催化剂研究

国内外甲苯歧化工艺研究,一直围绕着对传统的4种歧化工艺技术改进。一方面以提高产物中对二甲苯的热力学平衡浓度为目的,通过改变甲苯歧化催化剂的性能,以纯甲苯为原料,可获得较高的转化率和对二甲苯的选择性。另一方面,不断探索混合甲苯的歧化工艺,充分利用三甲苯原料;并综述了国内外甲苯歧化催化剂的现状及研究进展。