Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit

One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas–liquid–solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio(recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.     

渣油悬浮床加氢研究现状及发展趋势

本文介绍了渣油固定床、移动床、沸腾床和悬浮床四种加氢工艺及相应催化剂。重点综述了重油悬浮床加氢工艺和催化剂的研究及进展。     

渣油深度加氢裂化技术应用现状及新进展

长远来看,原油重劣质化的发展趋势不可避免,能够实现渣油清洁高效转化的深度加氢裂化技术是应对这一挑战的关键,正逐渐成为炼厂最主要的渣油加工技术手段。本文介绍了渣油沸腾床加氢裂化和渣油悬浮床加氢裂化技术的应用现状,结合技术特点和技术经济指标进行了对比分析,进一步综述了两种渣油加氢裂化技术的研发新进展。文中指出渣油沸腾床加氢裂化技术是目前最为成熟的渣油高效转化技术,未来仍将在渣油高效加工利用方面发挥重要作用,其中组合集成工艺以及未转化塔底油的处理工艺是其研发和应用的重点。渣油悬浮床加氢裂化技术具有高转化率的优势,但在工业化应用方面尚不如沸腾床成熟和普遍,仍需继续开发高活性、高分散的催化剂以及着重解决装置结焦问题,未来发展前景看好。     

提炼重油的沸腾床技术的介绍

重质原油产生的渣油可以通过多种工艺进行,在这些工艺当中,沸腾床催化加氢转化工艺可以深度转化杂质含量高的重质原料,其操作周期长,这可以通过经常在线更换催化剂床层的一小部分催化剂来实现。沸腾床反应器有一个器内液体循环系统以让催化剂床层沸腾。目前,全球有两家公司致力于这种工艺的开发,本文将介绍H-Oil的沸腾床加工技术。     

沸腾床渣油加氢处理催化剂失活研究

沸腾床催化剂失活主要是由于金属和焦炭沉积导致的,同时在沸腾状态下催化剂的物理和机械性质也发生了改变。使用后的催化剂向小的粒度分布方向偏移;催化剂沉积了大量的金属和焦炭,使催化剂的堆积密度增加,同时导致催化剂的孔结构、酸性质发生了变化。失活催化剂沉积的金属和焦炭在颗粒内外分布均匀,表明催化剂利用率较高。     

煤直接液化沸腾床加氢催化剂失活原因分析及使用方案探讨

简述了T-Star沸腾床加氢工艺的特点及优势。分析了T-Star催化剂的失活原因,合理的催化剂置换速率可将催化剂上的积炭、Fe和Ca的沉积量维持相对稳定;而磨损导致催化剂藏量降低对整体活性的影响较小。探讨了催化剂整体更换和日常置换两种不同使用方案的优劣。最后提出了开发新型催化剂和优化使用方案是今后工作的重点。     

渣油加氢技术应用现状及发展前景

渣油加氢技术是实现渣油清洁高效转化的关键技术,正逐渐成为炼厂主要的渣油加工技术手段。本文详细介绍了渣油加氢技术在应对石油需求量不断增加、原油重劣质化趋势加剧、环保法规日益严格、加工利用非常规石油资源等诸多挑战方面的重要性和紧迫性;重点分析了渣油固定床加氢处理技术、沸腾床加氢裂化技术和悬浮床加氢裂化技术的发展现状及未来趋势。渣油固定床加氢处理与催化裂化组合技术将是中长期内发展的重点技术,沸腾床加氢裂化技术需解决装置投资大、操作复杂等问题,悬浮床加氢裂化技术具有独特的优势,推广应用前景看好。     

Activity of hydroprocessing catalysts prepared by reprocessing spent catalysts

In this study, two spent catalysts from the 3rd and 4th fixed beds of the atmospheric residue desulfurization (ARDS) process and one spent catalyst from the H-Oil process employing the expanded bed were used as the starting material for preparation of hydroprocessing catalysts. The spent catalysts were used either in a coked or decoked form. The procedures involved pulverizing the spent catalysts before mixing, kneading and extruding with boehmite in the presence of peptizing agent such as HNO₃. The hydrodesufurization (HDS) and hydrodemetallization (HDM) activities of the new catalysts were evaluated in the microreactor using the atmospheric residue derived from Kuwait crude. The new catalysts prepared from the spent catalysts used in the fixed bed reactors exhibited higher activity than that of commercial catalysts. The HDS activity of the new catalysts prepared from spent catalysts used in the ebullated bed reactor was much lower than that of the other catalysts. This was attributed to a high content of vanadium in the former spent catalyst. At the same time, the adverse effect of vanadium on HDM was much less evident.     

CFD方法在固定床反应器传热研究中的应用

固定床反应器是一种常见的化学和生化反应器,由于内部结构十分复杂,固定床内的局部流动和传热过程研究一直是一个颇具挑战性的问题。有效参数法是长期以来固定床传热研究的常用方法,但是由于对固定床内温度场缺乏准确的了解,目前为止许多基于有效参数法的传热模型的普适性仍然存在问题。计算流体力学（CFD）的数值模拟方法是近年来应用于固定床流动和传热研究的一种新的研究方法,它通过数值方法求解流动和传递的微分方程组而获得流场和温度场。CFD数值模拟方法能够提供精确的局部流动和传递信息如速度分布、压力分布、温度分布、组分浓度分布等。本文综述和分析了CFD方法在固定床反应器的流动和传热研究领域的最新进展,讨论了CFD方法在该领域的应用前景。     

有机硅单体合成流化床反应器研究进展

介绍了应用于有机硅单体合成中的流化床反应器的工作原理及其技术的进展和国内外现状,分析了现有的流化床反应器内部换热结构及底部气体分布器,并指出了的主要优缺点。在此基础上重点介绍了一种新型有机硅单体流化床反应器以及改进的指管束二级管盘式导热油均布器。该设备的特点是：指管束中的导热油并联直流,取热均匀;能耗低,采用了催化剂直接回床技术,代表了有机硅流化床反应器新的发展方向。     

CFD simulation of fluidized bed reactors for polyolefin production – A review

This literature survey focuses on the application of computational fluid dynamics (CFD) in various aspects of the fluidized bed reactor. Although fluidized bed reactors are used in various industrial applications, this first-of-its-kind review highlights the use of CFD on polyolefin production. It is shown that CFD has been utilized for the following mechanisms of polymerization: governing of bubble formation, electrostatic charge effect, gas–solid flow behavior, particle distribution, solid–gas circulation pattern, bed expansion consequence, mixing and segregation, agglomeration and shear forces. Heat and mass transfer in the reactor modeling using CFD principles has also been taken under consideration. A number of softwares are available to interpret the data of the CFD simulation but only few softwares possess the analytical capability to interpret the complex flow behavior of fluidization. In this review, the popular softwares with their framework and application have been discussed. The advantages and feasibility of applying CFD to olefin polymerization in fluidized beds were deliberated and the prospect of future CFD applications was also discussed.     

Design of mixed conducting ceramic membranes/reactors for the partial oxidation of methane to syngas

The performance of mixed conducting ceramic membrane reactors for the partial oxidation of methane (POM) to syngas has been analyzed through a two‐dimensional mathematical model, in which the material balance, the heat balance and the momentum balance for both the shell and the tube phase are taken into account. The modeling results indicate that the membrane reactors have many advantages over the conventional fixed bed reactors such as the higher CO selectivity and yield, the lower heating point and the lower pressure drop as well. When the methane feed is converted completely into product in the membrane reactors, temperature flying can take place, which may be restrained by increasing the feed flow rate or by lowering the operation temperature. The reaction capacity of the membrane reactor is mainly determined by the oxygen permeation rate rather than by the POM reaction rate on the catalyst. In order to improve the membrane reactor performance, reduction of mass transfer resistance in the catalyst bed is necessary. Using the smaller membrane tubes is an effective way to achieve a higher reaction capacity, but the pressure drop is a severe problem to be faced. The methane feed velocity for the operation of mixed conducting membrane reactors should be carefully regulated so as to obtain the maximum syngas yield, which can be estimated from their oxygen permeability. The mathematical model and the kinetic parameters have been validated by comparing modeling results with the experimental data for the La_0.6Sr_0.4Co_0.2Fe_0.8O_3‐α (LSCF) membrane reactor. © 2009 American Institute of Chemical Engineers AIChE J, 2009     

Design of monolithic catalysts for multiphase reactions

Monolith reactors are emerging as an attractive alternative for gas-liquid-solid reactor applications. The use of monolithic catalysts in new reactors as well as in retrofit designs should be based on an optimal choice of monolith geometry and operating conditions.In this contribution, we illustrate through fundamental modeling of the transport-kinetic interactions in a monolith catalyst how such an optimal design may be evolved. We also highlight the potential benefits a monolith catalyst has as compared to a pellet-based trickle bed reactor.     

STRONG沸腾床示范装置工业应用

随着原油重质化程度的不断加深,沸腾床渣油加氢技术成为了炼厂提高渣油附加值的重要手段。抚顺石油化工研究院开发的STRONG沸腾床渣油加氢成套技术无需使用传统沸腾床技术中的高温高压循环泵及配套设备,提高了反应体系的稳定性与反应器空间利用率,降低了投资。首套采用STRONG沸腾床技术的工业化装置累计平稳运行8000 h,540℃+单程转化率达到了78%以上。     

Trickle-Bed Oxidation Reactors

For reactions necesitating a solid catalyst and which invoive both reisuvely volatile and nonvclarile reactants, three-phase reactirs are required. Equipment used to achieve intimate contacting of the three phases has been procominantly in the form of slurry reactors, analogous to the stirred-tank homogenous system, or fixed-bed reactors in which the two fluid phases flow through a stationary bed of catalyst particles. Trickle-bed reactors are a type ofthe second classification in which both gas and liquid flow downward through the catalyst bed. Such systems avoid the disadvantage of separating small catalyst particles from the fluid product streams associated with slurry reactors, and also avoid the limitation of flow rates uncountered with upflow or countercurrent flow through fixed beds.     

Mathematische Modellierung von Wirbelschichten

Mathematical modeling of fluidized bed reactors. In the past fluidized bed reactor modeling has focused on heterogeneously catalyzed gas-phase reactions. Recently, however, greatly increased activity is obvious in the field of fluidized bed combustion where attempts are made to describe coal combustion in the fluidized bed and emission of sulphur dioxide and nitric oxides from FBC units, with the ultimate aim of modeling the operating behavior of industrial fluidized bed combustors. The present paper surveys the state of the art in fluid bed reactor modeling. The influence of the fluid-dynamic state of fluidization which is governed by gas and solids properties, fluidizing velocity, and bed geometry, as well as the influence of different zones within the reactor and of design details, respectively, are discussed on the basis of several models described in the literature.     

浆态床渣油加氢催化剂研究进展

渣油加氢技术主要有固定床、沸腾床、移动床和浆态床。浆态床技术不存在催化剂的失活问题,几乎能处理各种性质的原料,是近年来的研究热点。浆态床技术通过加入催化剂达到劣质渣油改质的目的,使用的催化剂可分为不具有加氢活性的添加剂和具有加氢活性的催化剂两大类,添加剂的作用在渣油高转化率下较明显,所起的作用是阻隔生焦中间相的聚集以减少生焦;催化剂主要通过提供活性氢抑制大分子自由基的缩合和生焦并改质劣质渣油。对浆态床渣油加氢催化剂和添加剂的使用情况与机理进行总结,对未来发展进行展望,认为低成本有加氢活性的催化剂是未来浆态床渣油加氢催化剂的研究重点。     

STRONG沸腾床渣油加氢技术开发

介绍了中国石化自主开发的STRONG沸腾床渣油加氢技术,该技术具有反应器内温度均匀、传热传质好、装置操作灵活、运转周期长及原料适应性强等优点,可以加工高硫、高残炭、高金属等劣质渣油及其他非常规油品。此外,对沸腾床加氢技术的应用范围及前景进行了介绍。目前在金陵分公司建成一套5万t/a的工业示范装置,正在开展工业试验。     

粒径变化对沸腾床渣油加氢催化剂的影响

采用抚顺石油化工研究院(FRIPP)自主研发的微球形催化剂,以伊朗常压渣油(IRAR)为原料油,在间歇式高压反应釜内考察了粒径变化对沸腾床渣油加氢催化剂性能和加氢反应后催化剂性质影响.结果表明:减小催化剂粒径可以提高脱金属率、脱硫率、残炭转化率.生焦后催化剂的比表面积、孔容损失严重.