重油催化裂化沉降器结焦的研究进展

分析了重油催化裂化 (RFCC)沉降器结焦的影响因素和机理。反应油气中含有催化剂颗粒以及油气中重组分的冷凝是沉降器结焦的物理因素 ,而重芳烃、胶质、沥青质的高温缩合和油气中烯烃和二烯烃的环化聚合反应则是沉降器结焦的化学因素。通过对液相重组分高温缩合机理、相分离生焦机理和自由基反应机理等沉降器结焦机理的分析 ,认为沉降器中油气的气、液相分别遵循不同的结焦历程 ,抑制沉降器结焦的关键在于抑制反应油气中重组分的冷凝和缩短反应油气的停留时间     

浅析重油催化裂化装置沉降器结焦原因及对策

中国石油哈尔滨石化分公司1.2Mt·a-1三重油催化装置经检修改造后于2008年8月开工,该装置在2009年4月14日全厂停电后进入紧急停工状态。在恢复生产时,发现待生催化剂循环线路不畅,不能正常建立催化剂循环,被迫停工处理。打开沉降器后,发现现场结焦严重。本文通过分析沉降器结焦部位和结焦结构形态,结合生产中的操作数据,找出沉降器内结焦的原因,并提出相应的对策。     

催化裂化装置沉降器防结焦技术

对炼油企业来说,催化裂化设备是石油炼制二次加工中的关键部分。随着原油供应量日益增加,炼油厂中的催化裂化掺渣比日益增大的环境下,催化裂化装置沉降器的防结焦工作已刻不容缓。为此,本章重点剖析了催化裂化装置沉降器结焦的成因和特性,并主要研究了催化裂化装置沉降器防结焦问题的技术应用,希望能够为催化裂化装置解决类似问题提供一定的帮助。     

催化裂化沉降器结焦过程的研究进展

阐述了沉降器内油气结焦的原理,影响因素及各因素的作用,分析了结焦的形成过程,平均停留时间对结焦量的影响以及流动状态对结焦形貌的影响,介绍了防止沉降器结焦的研究进展情况和存在的问题.     

催化裂化沉降器的结焦原因和防焦措施

随着炼油厂催化裂化掺渣比的提高，催化裂化沉降器结焦日益严重，并直接影响威胁到催化裂化装置的正常运行。分析了原料性质、催化剂浓度和反应条件等因素对催化裂化沉降器结焦的影响，并通过总结国内外所采取的一些防焦措施，提出了今后的发展趋势和要求。     

重油催化裂化油浆系统结焦分析及优化措施

180万吨/年催化裂化装置于2011年6月下旬投产,随着装置运行时间的增加,逐渐发现油浆循环系统结焦较为严重。针对其结焦的原因及分析,在2012年5月检修中,我们做了大胆的尝试:在油浆蒸汽发生器冷路后新配一条管线至油浆下返塔,这项措施应用于生产实践后,取的了很好的效果。     

石油催化裂化沉降器抗结焦的研究与应用

重油催化沉降器内结焦严重,威胁装置的长周期平稳运行。中国石油大学(北京)针对沉降器结焦问题进行了较深入系统的数值模拟与实验研究,揭示了结焦的形成、发展、粘壁的机理和油气流动环境对结焦的影响,从沉降器工程装备设计方面开发了系列沉降器结焦综合防治技术并已成功应用于催化裂化工业装置,为重油催化裂化装置的长周期安全运行提供了技术支持。     

重油催化裂化结焦问题及解决策略

重油催化裂化生产过程中经常会出现局部结焦的问题,不但会影响设备的热传导效率,同时也会对设备的使用寿命产生很大的影响,很容易出现工艺操作波动或其他事故的发生.本文首先介绍了重油催化裂化生产过程中结焦问题的定义与主要类型,接着介绍了重油催化裂化生产过程中出现结焦问题的相关原因,最后结合上面原因分析进行相应的总结探讨,制定相...     

催化裂化沉降器顶部旋风分离器升气管外壁结焦的原因分析

本文在催化裂化沉降器升气管外壁颗粒沉积实验的基础上,结合气相流场数值模拟的结果,分析了升气管外近壁气相流场的分布特点和颗粒所受径向力的分布特点.结果表明对应工业旋风分离器结焦区域为边界层增厚区,非结焦区域对应边界层分离区.对应工业旋风分离器结焦区域,气体、颗粒径向速度均朝内;对应非结焦区域,气体、颗粒径向速度均朝外.在此基础上分析了结焦的原因.     

浅析重油催化裂化装置结焦原因及防止对策

在综合分析了重油催化裂化装置(RFCCU)容易结焦的部位及结焦原因,介绍了防止结焦的技术措施。认为在装置开工前,增强检修清焦质量、延长原料油塔外循环时间;生产中,保持操作平稳、尽量避免切断原料等事件的发生,加强对再生剂温度、预提升段催化剂密度、各喷嘴进料量和雾化蒸汽量、反应温度、沉降器出口温度、分馏塔底温度和塔底液位、油浆循环量、外甩量及油浆中固含量等参数的控制,采用优良的提升管出口技术,添加搅拌油浆等措施都对减少、防止RFCCU结焦有利。     

催化裂化结焦反应的研究进展

综述了近年来催化裂化结焦反应的研究进展情况,重点介绍了结焦反应的影响因素、焦炭对催化反应的影响、结焦机理以及焦炭的表征4个方面。研究认为,原料的性质、反应温度、催化剂的类型等因素均会对焦炭的生成产生影响。焦炭可以导致催化剂的失活,而位于孔道内部的焦炭对反应物或产物的扩散不利,进而影响产物的分布。研究表明,各种烃类组分形成焦炭的过程都必须经历芳香烃这一步。对于结焦催化剂可以采取多种表征手段,其中利用XPS以及GC-MS对焦炭进行表征的报道日益增多。尽管国内外对于催化裂化结焦反应的研究开展较早,然而探究焦炭的具体成分仍存在不小的困难,通过先进的表征手段鉴定焦炭中高缩合度芳烃组分以及如何减小催化裂化催化剂的结焦量将成为未来的研究方向。     

The effect of pre‐coking on the activity and selectivity of the catalytic cracking of squalane

The pre‐coking of cracking catalysts has been reported to increase the yield of light cycle oil from fluid catalytic cracking. The present studies investigating an equilibrated catalyst show that this is not the case. The effect of pre‐treating equilibrated catalysts with coke and with ammonia shows that conversion was decreased in both cases and the product selectivity of the process changed. Both coke and ammonia were found to decrease site density, reducing the importance of hydrogen transfer reactions. Increased yields of light cycle oil as a result of pre‐coking can only be expected with fresh catalyst, where small amounts of coke deactivate the most acidic sites. Such sites have already been deactivated on equilibrated catalyst. Copyright © 2004 Society of Chemical Industry     

Behavior of sulfur species present in atmospheric residue in fluid catalytic cracking

The selective removal of sulfur species in atmospheric residue (AR) is strongly wanted since the species of the hydrodesulfurized AR (HDS-AR) define the sulfur content of the product gasoline in the subsequent fluid catalytic cracking (FCC). Hence, the correlations between sulfur species in HDS-AR and FCC gasoline were explored in the present study. HDS-AR was fractionated into vacuum gas oil (VGO) and vacuum residue (VR) by distillation. Reactivities of HDS-AR (S = 3000 mass ppm) and its VGO (S = 900 mass ppm) were measured by micro activity test to clarify which fractions and sulfur compounds in HDS-AR were converted into gasoline and its sulfur species. The yields and sulfur contents of the product gasoline were 45.0 mass% and 52 mass ppm from HDS-AR and 47.7 mass% and 14 mass ppm from VGO, respectively. The sulfur content of the gasoline from HDS-AR was markedly higher than that from HDS-VGO. The saturate and aromatic fractions in HDS-AR are mainly converted to the gasoline in the FCC process, providing similar gasoline yields from HDS-VGO and HDS-AR. Thiophene, methylthiophenes, and benzothiophenes were major sulfur species in both gasolines from HDS-AR and HDS-VGO. Such sulfur species are concluded to be derived from benzothiophenes in VGO and dibenzothiophenes in VR fractions, respectively through hydrogen transferring ring opening and dealkylation during FCC. Sulfur compounds are also produced from H₂S and olefins in FCC, increasing the sulfur content in the product gasoline. The larger sulfur content in the gasoline from HDS-AR than that from HDS-VGO is ascribed to more H₂S being produced during the FCC process as well as dibenzothiophenes being present in the feed.     

Four-lump kinetic model for fluid catalytic cracking process

In the fluid catalytic cracking reactor heavy gas oil is cracked into more valuable lighter hydrocarbon products. The reactor input is a mixture of hydrocarbons which makes the reaction kinetics very complicated due to the involved reactions. In this paper, a four-lump model is proposed to describe the process. This model is different from others mainly in that the deposition rate of coke on catalyst can be predicted from gas oil conversion and isolated from the C₁–C₄ gas yield. This is important since coke supplies heat required for endothermic reactions occurring in the reactor. By this model we can also conclude that the C1–C4 gas yield increases with increasing reactor temperature, while production of gasoline and coke decreases.     

LV-23BC催化剂在渣油FCC装置上的应用

本文介绍了LV-23BC催化剂在庆化炼油厂Ⅱ套催化裂化装置上工业应用情况及使用效果。结果表明，LV-23BC具有良好的抗金属污染及渣油裂化能力、焦炭选择性和液化气选择性较高、催化剂单耗低、稳定性好等特点。     

LDO-75重油催化裂化催化剂的工业应用

介绍了LDO-75重油裂化催化剂在中国石油大连石化公司年产3.5 Mt重油催化裂化装置的工业应用.结果表明,LDO-75催化剂达到系统总藏量50%后,装置催化剂单耗由1.34kg·t-1降至1.04 kg·t-1,干气和油浆收率分别降低0.03%和1.36%,液化气收率增加1.19%,总液收提高1.42%.     

催化裂化油浆利用的技术进展

概述了催化裂化油浆的组成、性质和净化技术,介绍了催化裂化油浆在石油加工、石油化工领域利用的技术进展。分析了油浆在沥青改性、与煤共处理制取沥青改进剂、溶剂脱沥青、强化蒸馏、减黏裂化和延迟焦化工艺中的应用;评述了油浆的深度分离技术及分离所得组分的利用。     

降低催化汽油烯烃含量的灵活多效催化裂化工艺

在对催化裂化反应机理分析的基础上,提出了一种新的催化剂并联流动的双提升管催化裂化反应体系———灵活多效催化裂化(FDFCC)工艺。该工艺能显著降低催化裂化汽油的烯烃含量,中试及工业应用结果表明,烯烃含量可降低20%～30%,硫含量下降15%左右,改质汽油诱导期增加,马达法辛烷值(MON)和研究法辛烷值(RON)略有增加,苯含量基本维持不变,芳烃含量远小于规定指标。     

催化裂化提升管反应器中颗粒聚团裂化反应的数值模拟

Behavior of catalytic cracking reactions of particle cluster in fluid catalytic cracking (FCC) riser reactors was numerically analyzed using a four-lump mathematical model. Effects of the cluster porosity, inlet gas velocity and temperature, and coke deposition on cracking reactions of the cluster were investigated. Distributions of temperature, gases, and gasoline from both catalyst particle cluster and an isolated catalyst particle are presented. The reaction rates from vacuum gas oil (VGO) to gasoline, gas and coke of individual particle in the cluster are higher than those of the isolated particle, but it reverses for the reaction rates from gasoline to gas and coke. Less gasoline is produced by particle clustering. Simulated results show that the produced mass fluxes of gas and gasoline increase with the operating temperature and molar concentration of VGO, and decrease due to the formation of coke.