Migration and diffusion of molybdenum catalyst during CO/steam coal hydrogenation

CO/steam hydrogenation of an Australian high volatile bituminous coal was carried out at 350–400 °C with molybdenum as catalyst. In most experiments, molybdenum trioxide was mechanically mixed with coal, although impregnation of the coal with a solution of ammonium paramolybdate was also investigated. Naphthalene was used as a vehicle. Microscopic examination of the hydrogenation residues indicated that the molybdenum had migrated towards the coal surface at the early stages of CO/steam hydrogenation. It is thought that molybdenum carbonyl formation is the most likely pathway for molybdenum migration and diffusion. The physical distribution and quantity of catalyst had little influence on conversion yields, as would be expected if only a small proportion of the molybdenum is in highly mobile catalytic form. By itself, molybdenum hexacarbonyl was found to be an excellent CO/steam hydrogenation catalyst.     

Early coal hydrogenation catalysis

Three inputs were necessary to make catalytic hydrogenation of coal possible. One was the ammonia synthesis which, in 1910, introduced high pressure and temperature into the chemical industry. The second was the experimentation by F. Bergius who showed, in 1913, that coal can be liquefied by adding hydrogen at high pressure and temperature. The liquid products were similar to coal tar. They were not of the quality required for gasoline or diesel fuel production. The use of catalysts to refine the coal oil appeared then to be hopeless since coals contained sulfur, a poison for all then known hydrogenation catalysts. The third input was methanol synthesis in 1923. M. Pier found selective, oxidic catalysts that were less sensitive to sulfur than e.g. the metallic catalyst for the ammonia synthesis.In 1924 M. Pier, in the laboratories of the BASF, prepared sulfur resistant coal hydrogenation catalysts: sulfides and oxides of molybdenum, tungsten, and the iron group metals. With these catalysts it became possible to add hydrogen; split carbon-carbon bonds; and eliminate such heteroelements as sulfur, oxygen and nitrogen from coals and oils. Thus fuels were produced that met petroleum fuel specifications.Optimum catalyst action was achieved by subdividing coal hydrogenation into two stages. The coal was converted, with a dispersed catalyst in the “liquid phase”, into middle oil. This was then hydrogenated over fixed bed catalyst, in the “vapor phase”, to gasoline. On this basis a large scale demonstration plant for the liquefaction of central German brown coal was erected in 1927.The development of catalysts for these two stages proceeded on different routes. Liquid phase catalysts were discarded after one pass through the reactor. They were cheap, or used in very small amounts. It was found soon that coal of different rank required different catalysts, and that the mineral matter of the coal played an important role.The first commercially used vapor phase catalysts were of the hydrorefining type. Hydrocracking activity was achieved by using high temperatures. A great step forward was made in 1930 when a special preparation of tungsten disulfide permitted hydrocracking activity at low temperatures. Thus the first essentially dual function catalyst was found. Its hydrocracking activitity was further increased, and gasolines with a higher octane number were obtained by using it on acidic supports such as materials containing alumina-silica.Such supported catalysts were poisoned by the nitrogen compounds present in coal oils. Therefore a refining step for these oils was needed. The vapor phase was subdivided into the “prehydrogenation” (hydrorefining) and “splitting hydrogenation” (hydrocracking) steps. Further development of catalysts with specific functions for these two steps proceeded rapidly. In addition, separate catalysts were developed for the production of gasolines with a high content of aromatics.The various catalysts developed primarily for the hydrogenation of coal derived oils introduced hydrogen processing into the petroleum refining industry. There they were further modified and improved for the processing of petroleum. These improved catalysts, in turn, will be of help to a future coal liquefaction industry.     

煤焦油加氢裂化反应及其催化剂的研究

以煤焦油为原料,研究加氢裂化反应类型及反应产物油馏分的调制机理。以γ-Al2O3为载体,Mo、Ni为加氢活性组分,采用分步浸渍法制备负载型MoO3-NiO/γ-Al2O3加氢裂化催化剂。在高压反应釜上考察反应压力、反应温度对煤焦油加氢催化裂化反应的影响,比较了3种不同NiO质量分数的催化剂加氢活性,实验结果表明,NiO质量分数为3.68%的催化剂活性最好,并获得了低硫、低氮、低芳烃的反应产物油。     

煤焦油加氢工艺技术

针对鲁奇炉生产煤气过程的副产品煤焦油,以资源合理利用和环保为目标,利用现有的各种加氢工艺技术,及新型催化材料和助剂研制煤焦油专用加氢催化剂,选择合理的加氢工艺路线,利用炼油工业现代技术向煤加工领域改进性移植,降低加氢反应的氢分压,生产优质、环保的洁净燃料油,提高煤焦油的品质和煤焦油的附加值,并保护环境。     

预硫化型CoMo加氢脱硫催化剂性能

采用等体积浸渍方法制备CoMo催化剂,选用不同预硫化方法制备一系列硫化型CoMo催化剂,考察反应温度和空速对加氢脱硫性能的影响,并与对比剂进行比较。结果表明,硫化型CoMo催化剂在不同温度和空速下,具有较好活性,在200 h周期实验中,硫化型CoMo催化剂表现出良好的稳定性,脱硫率98.7%。TEM表征显示,硫化型CoMo催化剂具有更多的MoS_2堆垛层,形成更多高活性Co-Mo-SⅡ型活性相。     

新型磷化钨加氢精制催化剂的研究

以γ-Al₂O₃为载体,磷酸氢二铵和偏钨酸铵为原料,通过化学浸渍法制备系列磷化钨催化剂。以噻吩加氢脱硫反应为探针,考察浸渍顺序、WP负载量、焙烧温度和还原温度等因素对磷化钨催化剂加氢性能的影响。研究表明,WP负载质量分数为30％的WP-1催化剂具有较高的噻吩加氢脱硫活性, P的加入在一定程度上能够改善催化剂加氢活性。     

微波辅助制备Ni-W-P/γ-Al2O3煤焦油加氢催化剂

采用微波辅助浸渍法、微波管式焙烧制备了Ni-W-P/γ-Al₂O₃催化剂,并以中低温煤焦油轻油为原料,在固定床反应器装置上评价了催化剂的加氢活性。通过N₂吸附-脱附、GC-MS等方法对催化剂的物化性能及加氢产物油进行表征,并根据FHH模型,计算出催化剂的表面分形维数。结果表明,添加助剂P可调节催化剂的微观孔结构,改变催化剂的酸性分布与强度,并有助于加氢饱和反应的进行;当助剂P含量为0.9%时,催化剂的加氢脱硫、脱氮活性最高,加氢饱和性能最好;焙烧温度直接影响催化剂物性参数,当温度为500 ℃时,加氢活性最高、加氢产物品质最佳;微波焙烧相比常规制备方法,可增加晶粒烧结程度,形成更多三维孔隙结构,为加氢反应提供更大的表面和空间,且增加中等强度酸的酸量,更有助于表面活性组分的分散及硫化性的增强。     

Evaluation of hydrogenation catalyst activity

The AOCS Recommended Practice for testing activity of hydroge-nation catalysts was used to compare activity and properties of a number of commercial catalysts with the AOCS standard catalyst. Four of five commercial catalysts tested were similar to the standard but one commercial catalyst was markedly more active and more selective. It also was very difficult to filter after hydrogenation. Selectivity of the catalysts in hydrogenation of soybean oil was determined from change in fatty acid composition. The most selective catalyst produced the highest level oftrans isomers and the highest dropping point. Solid fat contents measured after 30 and 40 min of hydrogenation time were determined by wide-line nuclear magnetic resonance. The Recommended Practice and standard catalyst were useful tools in evaluating activity and selectivity of hydrogenation catalysts.     

超声辐射下钯系加氢催化剂的新型制备方法

提供了一种钯系加氢催化剂新型制备方法。采用经β-环糊精改性载体,以醋酸钯为活性组分前驱体在超声辐射下进行催化剂有机相制备;并以碳三液相加氢为探针反应,对利用4种不同方法制备的催化剂进行200 h对比评价。结果表明,该方法可有效提高活性组分分散度,使催化剂在保持较好加氢活性的同时具有较好的加氢选择性,为优化钯系加氢催化剂综合性能提供一条行之有效的途径。     

煤直接液化制油技术研究现状及展望

煤直接液化制油技术是促进煤炭清洁高效利用、缓解石油供需矛盾、保障我国能源安全的重要途径。为全面了解煤液化反应机理、动力学、催化剂及工艺的全过程,促进煤直接液化技术基础研究的快速进步和新工艺的开发,笔者综述了国内外在煤加氢液化反应机理、反应动力学、催化剂以及液化工艺方面取得的研究成果,重点介绍了德国IGOR、日本NEDOL和我国的神华煤液化工艺,分析了这些典型煤液化工艺的开发历程和特点;指明了煤直接液化制油技术发展趋势。煤的加氢液化反应是自由基反应机理,是一系列顺序反应和平行反应的综合结果,包含煤的热解、自由基加氢、脱杂原子和缩合反应等,总体上以顺序反应为主。借助同位素示踪、原位实时检测、等离子体技术以及微波快速加热技术等现代分析方法和试验手段,重点研究自由基的产生速率、活性氢产生速率及定量传递机理,有助于深入认识和精准阐明煤加氢液化反应机理。各国学者利用不同的研究方法,针对不同煤种、催化剂、工艺条件和供氢溶剂等,建立了各种各样的动力学模型。动力学模型从单组分到双组分和多组分,从连续反应、平行反应到复杂的网络反应,从最初的一步反应到后来较为合理的多段反应,模型越来越复杂,越来越接近工业应用。根据反应阶段不同进行分段处理的多组分"集总"反应动力学模型将是今后煤加氢液化反应动力学发展的主要方向。借助先进分析手段及科学的处理方法,建立真正揭示不同条件下煤液化动力学规律的通用型动力学模型是未来的发展趋势。借助纳米合成、等离子体等高新技术,调控组分配伍、降低催化剂粒径、优化制备方法是制备高活性催化剂的有效手段。强化系统合理配置和优化集成,重视煤的温和液化和分级转化,优化产品结构,发展直接液化-间接液化耦合技术是煤直接液化未来的发展趋势。     

Scanning electron microscopic study on the catalytic gasification of coal

The behaviour of nickel catalyst during coal gasification of Leopold coal (West Germany) was examined by means of scanning electron microscopy. Microscopic observations of the same field were made several times as the reaction proceeded. In addition to the uncatalysed gasification, the nickel-catalysed gasification was clearly observed under the microscope. With steam gasification, catalysts moved very actively, and they seemed to accelerate the gasification mainly by pitting holes into the char. The topological changes on char surfaces by hydrogasification were not so pronounced. The function of catalyst may not be restricted to the pit formation, for it seems to accelerate the gasification over all of the char surface. Because of the high hydrogasification temperature, agglomeration of catalyst takes place to a considerable extent. Finely dispersed nickel catalysts were observed when the coal had been pretreated with liquid ammonia. The catalytic activity of these fine particles was so large that the char beneath them was gasified rapidly.     

Kinetics of conversion of tetralin during hydrogenation of coal

Tetralin has been considered a reasonably good hydrogen donor for the hydrogenation of coal, but in the literature little attention has been given to the kinetics of its conversion. In this paper it is suggested that the conversion of tetralin, mainly to naphthalene, may be either a reversible or a non-reversible reaction depending on the catalyst employed. It is further concluded that stannous chloride, though considered one of the best coal hydrogenation catalysts, is inferior to cobalt oxide when the side reaction tetralin^→ decahydronaphthalenes and the rate of dehydrogenation of tetralin are considered.     

新型裂解汽油一段加氢催化剂的性能评价

对新研制的裂解汽油一段选择性加氢催化剂的性能进行了研究，考察了入口温度、反应压力、氢油比、空速、原料水含量及胶质含量等因素对双烯加氢率及加氢选择性的影响。结果表明，在适宜的工艺条件下，该种催化剂双烯加氢活性和选择性与现行工业用一段加氢催化剂性能相当，抗胶质性能较好，具有良好的工业应用前景。     

Catalytic reforming of tar during gasification. Part II. Char as a catalyst or as a catalyst support for tar reforming

Char, char-supported catalysts and ilmenite were investigated for the steam reforming of biomass tar derived from the pyrolysis of mallee wood in situ. Special attention was given to the reforming of aromatic ring systems in tar. The results indicated that the char-supported iron/nickel catalysts exhibited much higher activity for the reforming of tar than the char itself. Ilmenite and the char-supported iron catalyst contained similar active phase but showed different tar reforming activities. Kinetic compensation effects demonstrated that the reaction pathways on the char-supported catalysts were similar but were different from those on ilmenite. The proprieties of support could play important roles for the activities of the catalysts and the reaction pathways on the catalysts. Char would not only disperse the catalysts but also interact with the catalysts to enhance their activity for the steam reforming of tar.     

催化剂形态与酚类化合物加氢反应活性构效关系的研究进展

木质素是一种重要的生物质可再生资源,其降解后得到的酚类物质加氢后可得大量高附加值化学品,在环境治理和原料利用方面都有着十分重要的影响。本文综述了近年来国内外木质素酚类加氢反应催化剂的研究进展,总结了液相酚类催化加氢催化剂的种类、反应机理及结构敏感性因素对酚类催化加氢反应活性的影响,阐述了催化剂颗粒尺寸对液相酚类加氢反应活性影响,并以木质素液相酚类加氢反应催化剂的活性金属和载体为体系,对现有的结构敏感性反应中催化剂存在的形貌效应、晶相效应进行了讨论。提出未来可通过控制催化剂形貌和晶相来研究催化剂形态与催化活性之间的构效关系,为今后设计高活性木质素液相酚类加氢催化剂提供借鉴和参考。     

Catalytic coprocessing of LDPE with coal and petroleum resid using different catalysts

Catalytic coprocessing of low density polyethylene (LDPE) with coal and heavy petroleum resid was investigated using four different catalysts that included both hydrotreating and hydrocracking catalysts. Reaction systems that were evaluated included LDPE alone; LDPE with coal; and LDPE, coal, and resid. The catalysts used were NiMo/Al₂O₃, a hydrotreating catalyst with some hydrocracking activity, and the hydrocracking catalysts Zeolyst 753, NiMo/zeolite, and HZSM-5. These catalysts were reacted individually or in combinations of 10 wt.% of each hydrocracking catalyst in NiMo/Al₂O₃. The catalytic reactions were performed at two temperatures, 400 and 430°C, using 1 wt.% of each catalyst or a combination of catalysts on a total feed basis. The effects of the different catalysts on the reaction products were measured in terms of solvent fractionation and total boiling point distribution. Reactions at the higher reaction temperature of 430°C resulted in substantially higher conversion and production of lighter products than the reactions at 400°C. The LDPE reaction system was sensitive to the catalyst type, and yielded increased conversion and lighter products when Zeolyst 753 and NiMo/zeolite were used. By contrast, the conversion and product slate obtained from the LDPE and coal systems were low and showed no effect due to the different types of catalyst. Introduction of resid to the LDPE/coal system increased the reactivity of the system and allowed the catalysts to have a larger effect. The hydrocracking catalysts were the most active in producing more conversion and hexane soluble material. Comparison of the effect of increasing the reaction time up to 5 h with 1 wt.% catalyst loading to the effect of increasing the catalyst loading from 1 wt.% to 10 wt.% for a reaction time of 1 h showed that increased reaction time was much more effective than catalyst loading in converting the solid LDPE to liquid reaction products.     

Ni/W比对NiWCx催化剂加氢性能的影响

过渡金属碳化物具有类似贵金属的电子结构和加氢性能。采用等体积浸渍法制备了不同Ni/W比的NiW/γ-Al₂O₃催化剂,以程序升温碳化法转化为NiW碳化物后对芳烃模型化合物和低温煤焦油中分离所得芳烃组分进行加氢处理。催化剂的N₂吸附、XRD、H₂-TPR和SEM表征表明,Ni的添加促进了载体表面WO₃物种的分散和还原,抑制了WO₃晶体的团聚和大晶粒的生成。萘的加氢实验表明,Ni/W原子比为0.6时催化剂的活性最佳,而添加苯酚和吡啶后的模型油加氢过程中萘的转化率和十氢萘的产率均明显下降,Ni/W原子比为0.47和0.6的催化剂性能相近,煤焦油中芳烃组分加氢后Ni/W原子比为0.47的催化剂性能更优。结果表明,Ni和W均具有良好的加氢活性,但Ni耐杂原子性能较差,二者存在一个最佳的配比以使加氢性能更优。有杂原子化合物存在时,如煤基芳烃组分的加氢,Ni/W原子比为0.47的NiW碳化物催化剂具有更好的加氢性能。     

Continuous slurry hydrogenation of soybean oil with copper-chromite catalyst at high pressure

Selective hydrogenation of soybean oil to reduce linolenic acid is accomplished better with copper than with nickel catalysts. However, the low activity of copper catalysts at low pressure and the high cost of batch equipment for high-pressure hydrogenation has precluded their commercial use so far. To evaluate continuous systems as an alternative, soybean oil was hydrogenated in a 120 ft × 1/8 in. tubular reactor with copper catalyst. A series of hydrogenations were performed according to a statistical design by varying processing conditions: oil flow (0.5 L/hr, 1.0 L/hr and 2.0 L/hr), reaction temperature (180 C and 200 C), hydrogen pressure (1,100 psig and 4,500 psig) and catalyst concentration (0.5% and 1.0%). An iodine value (IV) drop of 8–43 units was observed in the products whereas selectivity varied between 7 and 9. Isomerization was comparable to that observed with a batch reactor. Analysis of variance for isomerization indicated interaction between catalyst concentration and hydrogen pressure and between catalyst concentration and temperature. The influence of pressure on linolenate selectivity was different for different temperatures and pressure. Hydrogenation rate was significantly affected by pressure, temperature and catalyst concentration.     

煤催化加氢气化研究进展

煤加氢气化制天然气技术具有工艺路径短、热效率高等优点,其应用基础研究备受关注。但煤中存在部分致密的芳香碳结构,加氢反应性较差,即使在苛刻的反应条件下(~1 000℃、~7 MPa H_2),仍难以转化。通过引入催化剂,进行煤催化加氢气化可在温和的反应条件下实现煤的碳转化率和CH_4收率的同步提高。论述了碱金属(K、Na等)、碱土金属(Ca)和过渡金属(Fe、Co、Ni等)催化剂对模型碳加氢气化的催化作用原理。探讨了反应温度、氢气压力、和碳结构对C-H_2催化反应的影响规律,分析了适用于原煤催化加氢气化的最佳催化剂及工艺条件,并从CH_4和轻质液体焦油等产物生成规律、煤中碳结构随着反应进行的衍变过程等角度,讨论了催化剂分别对煤加氢热解和热解半焦加氢气化的催化作用行为。提出了煤催化加氢气化联产CH_4和轻质液体焦油技术从基础走向应用的进一步研究建议。现有研究结果表明,过渡金属与碱土金属组成的二元催化剂(Fe/Co/Ni-Ca)对煤加氢气化的活性较高。过渡金属元素在反应过程中主要提供C-H_2反应所需的活性氢,并削弱C—C键的键能;碱土金属元素Ca主要促进Fe/Co/Ni的分散,防止其发生硫中毒失活,并增强Fe/Co/Ni与碳之间的相互作用。温度升高一方面为化学键断裂过程提供了更高能量,加速C-H_2反应,另一方面促进催化剂在煤结构中扩散,提升催化剂的供氢和断键效率。升高压力促进了活性氢的供应,同时CH_4浓度得到稀释,反应向生成CH_4的方向移动。以5%Co-1%Ca为催化剂,在850℃、3 MPa H_2反应条件下,30 min内可同时达到90.0%的碳转化率和77.3%的CH_4收率。Co-Ca催化剂在煤加氢热解过程中具有催化解聚和催化加氢的作用,提高焦油和CH_4收率,同时催化剂在煤加氢热解过程中对煤结构产生催化活化作用,使得生成的半焦具有较高的气化活性。煤催化加氢气化的机理研究目前仍处于推测阶段,另外,该技术气化剂、煤种的适应性,催化剂循环利用性能有待进一步阐明。     

响应面法优化Ni-P/APO-11非晶态催化剂催化松节油加氢反应

以二异丙胺、氢氧化铝为原料,采用水热合成法制得APO-11磷酸铝分子筛。采用化学还原法制备非晶态Ni-P/APO-11催化剂用于α-蒎烯加氢反应,考察了α-蒎烯加氢反应条件,通过响应面法实现进一步优化,而后采用XRD、BET、SEM、XPS、ICP等对该催化剂进行了表征。结果显示,在反应温度124.8℃,反应压力4.9 MPa,催化剂用量6.3%,反应时间90 min时,α-蒎烯转化率为99.45%,顺式蒎烷选择性97.35%。为进一步拓宽该催化剂使用范围及提高松节油体系的深加工利用水平,将该催化剂用于松节油其他组分的加氢反应中,展现出良好的催化活性,原料转化率均可达到99%以上,选择性65%以上。