高氮原料的催化裂化研究进展

从FCC催化剂碱氮中毒机理、含氮化合物的转化等角度分析了含氮化合物对催化裂化的不利影响.在此基础上,对目前已工业化和在研的各种高氮原料直接催化裂化技术进行了概述,展望了高氮原料催化裂化发展的方向.     

流化催化裂化再生器数学模型的研究

本文的目的是将流态化理论应用于细粉催化剂流化催化裂化再生器数学模型之中。借助于光导纡维测试技术研究了在再生催化剂流化床中颗粒流动速度及其径向分布规律和气泡频率及其径向分布规律。实验所用装置为φ300×11400三维冷模流化床,介质为空气和工业再生催化剂,根据实验结果提出了一个流化催化裂化再生器数学模型。在模型中考虑了稀相的影响,并采用工业数据对所提出的模型进行了模型参数估值,得到了比较稳定的模型参数值。     

催化裂化装置再生斜管流化状态异常分析

再生斜管是维持反应器与再生器之间催化剂循环的重要通道，中国石化扬子石化有限公司炼油厂2.0Mt/a催化裂化装置存在流化异常的问题，表现为再生滑阀开度波动（44%～53%）、反应温度波动（515～526℃）、两器差压波动（27～51 kPa）。通过对影响再生斜管流化异常的因素进行分析，结果表明，采取置换催化剂改善催化剂中毒情况、调整再生斜管松动风量、装置日常操作精细化与标准化等措施后，再生斜管的流化问题得到改善。     

国内化学工程文献摘要

根据流化床气泡理论,推导出流化催化裂化反应器和再生器密相床平均密度的计算公(?),提出了一套计算再生器稀相催化剂密度分布公式。     

催化裂化催化剂显微观测图像技术的工业应用

催化裂化催化剂显微观测图像技术是用于流化催化裂化装置反应再生系统运行故障诊断的技术。严格的操作程序是获得清晰图像并具有可比性的可靠保证。阐述催化裂化催化剂颗粒显微观测实验室建设过程中的注意事项,包括显微照相设备的选择、实验室配置、样品制作和图像处理等,对操作过程进行标准化管理,保证了图像的可靠性和可比性。目前,该技术在装置事故的诊断上初显威力,对减少催化剂跑损和判断三旋效率具有指导作用。     

基于ESI FT-ICR MS对焦化蜡油窄馏分及其催化裂化液体产物中碱性含氮化合物的表征

利用实沸点蒸馏装置对辽河焦化蜡油进行窄馏分切割,并利用电喷雾傅里叶变换离子回旋共振质谱对窄馏分及其催化裂化液体产物中的碱性含氮化合物进行表征,分别获得随馏分沸点的升高碱性含氮化合物的分布规律和在反应过程中的迁移规律。结果表明,不同窄馏分中都以N1类碱性含氮化合物为主,N1O1类次之,其它类型的相对丰度均较低;随馏分沸点的升高,DBE>10的N1类碱性含氮化合物的总相对丰度明显增加,但其侧链所含碳原子数逐渐减小;DBE<10的N1类碱性含氮化合物的总相对丰度变化不大,但其侧链所含碳原子数显著增加;经过催化裂化反应,不同窄馏分所得液体产物中N1类碱性含氮化合物的结构分布差异显著变小,DBE<10的N1类碱性含氮化合物对催化剂活性位的毒害作用最大。     

基于ESI FT-ICR MS对焦化蜡油窄馏分及其催化裂化液体产物中碱性含氮化合物的表征

利用实沸点蒸馏装置对辽河焦化蜡油进行窄馏分切割,并利用电喷雾傅里叶变换离子回旋共振质谱对窄馏分及其催化裂化液体产物中的碱性含氮化合物进行表征,分别获得随馏分沸点的升高碱性含氮化合物的分布规律和在反应过程中的迁移规律。结果表明,不同窄馏分中都以N1类碱性含氮化合物为主,N1O1类次之,其它类型的相对丰度均较低;随馏分沸点的升高,DBE10的N1类碱性含氮化合物的总相对丰度明显增加,但其侧链所含碳原子数逐渐减小;DBE10的N1类碱性含氮化合物的总相对丰度变化不大,但其侧链所含碳原子数显著增加;经过催化裂化反应,不同窄馏分所得液体产物中N1类碱性含氮化合物的结构分布差异显著变小,DBE10的N1类碱性含氮化合物对催化剂活性位的毒害作用最大。     

催化裂化装置反应再生系统单独停工检修

从工艺流程分析入手,实施添加隔断盲板等检修管理措施,制定完善的停工检修方案,将反应再生系统与其他系统隔断,查找并解决了催化剂待生线路流化异常的原因,顺利完成了催化裂化装置反应再生系统单独停工检修。     

20世纪60年代微球硅铝裂化催化剂研发过程的回顾——回顾历史,指引未来

20世纪60年代,世界上最先进的炼油工艺是流化催化裂化工艺。在一个密相的催化剂流化床层中,重油被裂化成汽油、柴油和液化气,同时,催化剂上积炭,然后输送到一个再生器中烧去积炭,再返回反应器。1960年,大庆油田开发后,我国准备建设一座250万吨/年的炼油厂,其中最核心的工艺就是流化催化裂化,其中所用的催化剂就是微球硅铝裂化催化剂。1960年春节前夕,石油工业部余秋里部长在部里举行宴会,我应邀出席,跟余部长坐在一桌。余部长对我说:"你一年后给我把微球催化剂交出来。" 一年之内,要从科研开始,实现微球硅铝催化剂建厂生产,根本不可能。     

面向21世纪的炼油催化技术的新进展(续完)

本文系22篇有关炼油催化技术最新文献述评, 它涉及异构化、烷基化以及重整油改质与脱苯用催化剂, 馏份油的加氢处理与加氢裂化, 流化催化裂化渣油流化催化裂化和增产烯烃的流化催化裂化工艺, 渣油加氢处理以及生物催化脱硫。     

Nature of nitrogen specie in coke and their role in NOx formation during FCC catalyst regeneration

NO_x emission during the regeneration of coked fluid catalytic cracking (FCC) catalysts is an environmental problem. In order to follow the route to NO_x formation and try to find ways to suppress it, a coked industrial FCC catalyst has been prepared using model N-containing compounds, e.g., pyridine, pyrrole, aniline and hexadecane–pyridine mixture. Nitrogen present in the FCC feed is incorporated as polyaromatic compounds in the coke deposited on the catalyst during cracking. Its functionality has been characterized using XPS. Nitrogen specie of different types, namely, pyridine, pyrrolic or quaternary-nitrogen (Q-N) have been discriminated. Decomposition of the coke during the catalyst regeneration (temperature programmed oxidation (TPO) and isothermal oxidation) has been monitored by GC and MS measurements of the gaseous products formed. The pyrrolic- and pyridinic-type N specie, present more in the outer coke layers, are oxidized under conditions when still large amount of C or CO is available from coke to reduced NO_x formed to N₂. “Q-N” type species are present in the inner layer, strongly adsorbed on the acid sites on the catalyst. They are combusted last during regeneration. As most of the coke is already combusted at this point, lack of reductants (C, CO, etc.) results in the presence of NO_x in the tail gas.     

The correlation between nitrogen species in coke and NOx formation during regeneration☆

Nitrogen oxides(NO x)emission during the regeneration of coked fluid catalytic cracking(FCC)catalysts is an environmental issue.In order to identify the correlations between nitrogen species in coke and different nitrogencontaining products in tail gas,three coked catalysts with multilayer structural coke molecules were prepared in a fixed bed with model compounds(o-xylene and quinoline)at first.A series of characterization methods were used to analyze coke,including elemental analysis,FT-IR,XPS,and TG–MS.XPS characterization indicates all coked catalysts present two types of nitrogen species and the type with a higher binding energy is related with the inner part nitrogen atoms interacting with acid sites.Due to the stronger adsorption ability on acid sites for basic nitrogen compounds,the multilayer structural coke has unbalanced distribution of carbon and nitrogen atoms between the inner part and the outer edge,which strongly affects gas product formation.At the early stage of regeneration,oxidation starts from the outer edge and the product NO can be reduced to N_2 in high CO concentration.At the later stage,the inner part rich in nitrogen begins to be exposed to O_2.At this period,the formation of CO decreases due to lack of carbon atoms,which is not bene ficial to the reduction of NO.Therefore,nitrogen species in the inner part of multilayer structural coke contributes more to NO X formation.Based on the multilayer structure model of coke molecule and its oxidation behavior,a possible strategy to control NO X emission was discussed merely from concept.     

催化裂化油浆系统结焦原因及预防措施

介绍1.8 Mt/h催化裂化装置油浆系统结焦形成的机理并分析油浆系统结焦的原因,结合装置运行的实际操作以及经验,提出预防油浆系统结焦的措施。催化裂化油浆结焦的原因主要由一些稠环化合物具有热缩和反应活性,这些稠环化合物吸附、粘附在催化剂上并发生缔合或缩合反应并生成由有机物与无机物组成的混合结垢催化剂、焦炭及少量金属化合物。通过降低油浆密度、降低分馏塔底温度、加大油浆阻垢剂注入量等措施可以有效地预防油浆系统结焦。     

结炭B-02催化剂烧炭再生本征动力学模型

以工业两段绝热床中运行近4000h的结炭B—02催化剂为研究对象,利用内循环无梯度反应器,求得催化剂烧炭再生本征动力学模型.由于催化剂中的结炭是多核芳烃,因此可简单地以碳氧化和氢氧化的动力学方程表征烧炭再生动力学模型.碳氧化动力学方程为-dN_c/N_Cdt=K_Cp_(O_2)~(0.3)(N_C/N_C)~1.3式中,一段催化剂 K_C=13.37exp[-78.97×10~3/(RT)]二段催化剂 K_C=96.54exp[-89.30×10~3/(RT)]氢氧化动力学方程为-dN_H/N_Hdt=K_H(N_H/N_H)~1.1式中,一段催化剂 K_H=0.48exp[-39.04×10~3/(RT)]二段催化剂 K_H=4.79exp[-52.03×10~3/(RT)]     

Regeneration of coked catalysts

The intrinsic kinetics of carbon removal from a coked catalyst have been determined. Measurements have also been made of the transient temperature distribution inside a coked catalyst pellet during regeneration. These transient temperature distributions have been compared with predictions based on the sharp interface unreacted core model and on the finite thickness reaction zone model. The experimentally determined values of the maximum temperature rise were found to be in good agreement with the latter model but the sharp interface unreacted core model predicted temperature rises of a very much greater magnitude.     

A model for coke oxidation from catalyst pellets in the initial burning period

A model for predicting the transient temperatures during the initial period of regeneration of a coked catalyst has been developed. The model considers the reaction of both hydrogen and carbon in the coke. The hydrogen is assumed to react at a sharp interface and the carbon is assumed to react in the diffusion zone between the hydrogen interface and the surface. The maximum temperature profiles predicted by the model give better agreement with the experimental data reported in the literature especially in the lower temperature range of regeneration.     

GC-AED法研究催化裂化柴油中硫氮化合物

采用气相色谱-原子发射光谱（GC-AED）联用技术对FCC柴油中的含硫化合物、含氮化合物进行定性定量研究。结果表明：FCC柴油中硫化物的类型主要是噻吩类衍生物、苯并噻吩、苯并噻吩类衍生物、二苯并噻吩、二苯并噻吩类衍生物,其中苯并噻吩类衍生物、二苯并噻吩类衍生物的硫质量分数占总硫质量分数的93．6％以上。氮化物主要为碱性氮化物（Nb）和非碱性氮化物（Np）两大类型,其中碱性氮化物主要是苯胺及其衍生物,喹啉含量很低,约占总氮质量分数的0．1％,非碱性氮化物主要包括吲哚及其衍生物和咔唑及其衍生物,而咔唑类氮化物一般约占总氮质量分数的64％。不同来源的FCC柴油,其所含硫化物、氮化物的含量和分布不同。应根据其硫化物、氮化物的分布类型及规律,开发合适的柴油脱硫脱氮催化剂及相关工艺。     

Synergetic effects of Y-zeolite and amorphous silica-alumina as main FCC catalyst components on triisopropylbenzene cracking and coke formation

The synergetic effects of HY-zeolite and silica-alumina (SA), as two major components of an FCC catalyst, on the cracking activity and coking tendency during catalytic cracking of 1,3,5-triisopropylbenzene (TiPB, as a resid representative) were studied. NaY-zeolite and SA were synthesized by hydrothermal and co-precipitation methods, respectively, and ammonium exchanged for three times at 80 °C. The catalysts were characterized by XRD, XRF, SEM, BET, AAS and ammonia TPD techniques. TiPB cracking was investigated on four different catalyst configurations including SA, Y-zeolite, SA.Y and SA-Y in a fixed bed reactor. SA.Y stands for physical mixture of equal amounts of Y-zeolite and SA. For SA-Y, a bed of SA was placed upstream of the same amount of Y-zeolite. The catalysts were in-situ activated at 475 °C and evaluated by TiPB cracking at 350 °C. The coke content of the catalyst beds, after 40 min cracking of TiPB, was estimated by TPO using an FT-IR gas cell. At 3 min time on stream, 5.2 times higher yield of benzene, as a deep cracking product, is observed on SA-Y as compared to SA.Y. The TiPB conversion decreases in the order of SA-Y > SA.Y > Y-zeolite ? SA. Furthermore, as compared to Y-zeolite, 24% lower coke is formed on SA-Y. Also CO evolution during TPO of coked SA-Y catalyst is about 24% lower than that of the coked zeolite. As a result, protecting of Y-zeolite by SA from direct exposure to resid feed enhances the cracking activity, decreases the tendency to coke formation and diminishes CO emission in the catalyst regeneration process.     

催化剂烧炭再生模拟和分析

催化剂烧炭再生是非定态过程。本文建立了绝热反应器内催化剂烧炭模型,利用移动边界正交配置法求解。以结炭的BO2催化剂再生为工作反应,模拟预测与实验值吻合良好。模拟计算表明,用递升进口温度序列烧炭,使再生时间明显缩短。     

Influence of the final “ageing” temperature on the regeneration behaviour and location of the coke obtained in the HZSM-5 and USY zeolites during the LDPE cracking

In this work, the influence of the “ageing” temperature on the location and regeneration behaviour of the coke obtained in the cracking of LDPE in the presence of HZSM-5 and USY zeolites is studied. The coke content in the zeolites is influenced by the thermal treatment, and for both zeolites studied, the higher the final cracking temperature the lower the coke content. The nitrogen adsorption isotherms have shown the different deactivation mechanisms, related to the possible different locations of the coke on each zeolite and the influence of the final cracking temperature on these parameters. The regeneration study of the coked zeolites has shown that the coke combustion process strongly depends on the insoluble content of the coke (i.e., of the presence of bulky polyaromatic compounds) and of the zeolite framework.