The effects of gas-to-oil rate in ultra low sulfur diesel hydrotreating

Hydrotreating has become a critical refining process as fuel sulfur specifications are tightened around the world. Recently, refiners in the United States have been learning how to optimize the performance of ultra low sulfur diesel (ulsd) hydrotreaters. The gas-to-oil feed rate ratio is known to be an important variable in this respect. It is well known that the gas-to-oil rate must be kept high enough to maintain the desired hydrogen partial pressure through the hydrotreating reactor, and to minimize the inhibiting effect of hydrogen sulfide. A lesser-known effect is the effect of gas-to-oil rate on the vapor–liquid equilibrium in the reactor. Changing the gas-to-oil rate alters the distribution of reactants between vapor and liquid in a way that changes the relative reaction rates of different sulfur compounds. This paper presents some pilot plant data and analysis showing this effect of phase equilibrium in deep diesel desulfurization. The effect can be modeled using the Frye–Mosby equation, which accounts for the effects of feed vaporization and phase equilibrium on the reaction rates of individual sulfur compounds in a trickle bed hydrotreater.     

前郭石化分公司柴油加氢装置工艺技术路线研究

前郭石化分公司柴油产品质量与国家新标准存在差距，主要原因是催化裂化柴油质量差，催化柴油必须经过加氢装置进行处理。根据企业实际生产情况，柴油加氢装置宜选择加氢精制、改质及临氢降凝三位一体的工艺技术路线，这样既能满足提高柴油产品质量的要求，又能生产经济效益比较好的低凝柴油。     

Alumina-silica binary mixed oxide used as support of catalysts for hydrotreating of Maya heavy crude

Alumina-silica binary mixed oxide support is used to prepare catalysts for hydrotreating of Maya heavy crude. Support is prepared by urea hydrolysis. Sequential incipient wetness and co-impregnation techniques are employed for preparation of catalysts. Ammonium heptamolybdenum is used as precursor of MoO₃. Catalysts are characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR) and the pore size distribution. Hydrodemetallation (HDM), hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and asphaltene conversion (HDAsp) reactions are studied on these catalysts. One reference catalyst is also taken for comparison. Coke and metals depositions on spent catalysts are measured. The catalyst deactivation rate is also studied. The X-ray diffraction (XRD) results reveal that molybdenum atoms are well dispersed into CoMo catalyst, whereas MoO₃ crystalline phases are found in PCoMo and PNiMo catalysts. TPR reduction profiles are different for different catalysts. The laboratory made catalyst is reduced at one temperature, whereas the reference catalyst shows two reduction profiles. The reference catalyst shows the highest activities among four catalysts. The highest HDM and HDAsp activities of the reference catalyst may be due to its bigger pore diameter. The presence of TiO₂ in the reference catalyst enhances HDS and HDN activities. The CoMo catalyst shows higher activities than those of PCoMo and PNiMo catalysts. The presence of crystalline MoO₃ causes for lower activities of catalysts PCoMo and PNiMo.     

Aromatic Hydrogenation Catalysis: A Review

High aromatic content in diesel fuel has been recognized both to lower the fuel quality and to contribute significantly to the formation of undesired emissions in exhaust gases [1, 2]. Because of the health hazards associated with these emissions, environmental regulations governing the composition of diesel fuels are being tightened in both Europe and the United States, leading to limitations on aromatics [3, 4].     

常压渣油加氢处理技术的研究开发

介绍了几年来中国石化抚顺石油化工研究院(FRIPP)在常压渣油固定床加氢处理技术的研究开发方面所取得成就,此项技术包括催化剂研制和相应工艺的研究试验。FRIPP开发的常压渣油加氢处理催化剂R3中试结果表明在反应温度384℃,反应压力14.0MPa,体积空速0.20h-1,氢油体积比为700∶1的条件下,催化剂活性和稳定性良好,与参比催化剂性能相当。1999年底在大连西太平洋石油化工有限公司(WEPEC)的ARDS装置上进行工业应用,催化剂运转周期达到17个月,结果表明催化剂活性和稳定性良好,满足工业生产要求。     

Comparative investigations of hydrotreating catalysts in laboratory and process conditions

Hydrotreating procedures have exceptional place in modern oil refineries as the most effective way to improve oil products quality. The variation of process parameters by laboratory reactor simulation using different crudes and catalysts is a useful and economic tool for the optimisation of these processes in practice. There are presented comparative investigations of commercial industrial hydrotreating catalysts and various feeds as a support for real refinery practice.     

High quality diesel by hydrotreating of atmospheric gas oil/light cycle oil blends

An improved process for high-quality diesel fuel production by hydrotreating atmospheric gas oil (SRGO) and light cycle oil (LCO) blends is presented in this paper. For this purpose, a set of blends of 5, 10 and 15% by volume of LCO with final boiling points of 300, 325 and 350 °C with a full range gas oil (FBP 350 °C) was hydrotreated in a pilot plant at 340-380 °C, 5.4 MPa, 2.5 h⁻¹ LHSV using a commercial Co-Mo catalyst. A relationship between the concentration of refractory sulfur compounds (those boiling above 316 °C) and aromatics content in the feedstock with the hydrotreating temperature required for meeting a 0.05% sulfur specification was found.The experimental data obtained during the desulfurization was quantitatively represented by a 1.50 to 1.56 order rate equation, with activation energies between 18.9 and 34.1 kcal/mol, depending on the feedstock.     

加氢装置运行中进行技术改造的安全管理

总结了加氢装置技术改造项目边生产边施工用火安全管理经验,介绍了在生产装置内施工用火的火灾危险性和施工安全防护措施,确保了边生产边施工用火的安全。     

渣油加氢转化过程中沥青质的结构变化

通过1H -NMR、元素分析和平均相对分子质量等方法研究了不同沥青质质量分数的渣油在高压釜内加氢反应前后沥青质结构和组成的变化。结果表明, 加氢反应后沥青质的平均相对分子质量和H/C 原子比减小, 芳碳分率增大, 芳香环系周边氢取代率σ及芳香环系缩合度参数H AU/ CA 减小, w(HA)增加, 而w(Hα)、w(Hβ)、w (H γ)减少, 沥青质的取代芳碳分率减少, 质子芳碳分率增加, 表明加氢反应后所得沥青质的缩合度增大, 沥青质发生了明显的脱烷基侧链反应。加氢后沥青质的含硫质量分数降低, 含氮质量分数增加。随原料中沥青质质量分数的增加, 加氢后沥青质的环烷环数和芳香环数均逐渐增加, 尤其是芳香环数, 甚至会大于原生沥青质。渣油加氢过程中沥青质主要是以单元薄片为基本单元参与反应的, 沥青质的加氢反应, 既有自由基反应, 又有正碳离子反应。     

A comparative activity study of a new ultra-dispersed catalyst system for a hydrocracking/hydrotreating technology using vacuum residue oil: Merey/Mesa

Ultra-dispersed catalysts give an improvement over the main reactions activity by having a low deactivation rate. They provide as well other advantages like a diminution in the catalysts metal concentration, a reduction in contaminants and also these catalysts can be used in almost every area where heterogeneous catalysts are used. Catalysts synthesis optimization is important to improve process recovery, especially in hydrocracking/hydrotreating processes, where feedstock is vacuum residue. Here, we have evaluated the catalytic performance of two molybdenum–nickel catalysts prepared using different emulsion formulation, named E-T (base catalyst) and AT-48 (new catalyst). Our results showed that, the percentage of converted products for VR 500 °C⁺, asphaltenes and microcarbon are comparable for both E-T and AT-48 catalysts, despite the fact that for the latter a lower molybdenum concentration was used. In addition, post-catalytic particles analyses using SEM and TEM techniques demonstrated that AT-48 catalyst showed a non-aggregated and homogeneous narrower distribution of metallic particles than E-T one. The lower average particle size distribution is related to the improvement of the liquid product yields for the hydroconversion of Mery/Mesa VR using the AT-48 catalyst.