MOLECULAR MODELING AND OPTIMIZATION FOR CATALYTIC REFORMING

In this paper, molecular modeling and optimization for the naphtha catalytic reforming process is studied. The catalytic reforming process is for producing high octane number gasoline by reforming reactions in three sequencing fixed bed reactors. Feed naphtha coming from an atmospheric distillation unit consisted of molecules from C5 to C10 including paraffin, iso-paraffin, naphthene, and aromatic. The molecular reaction network consisted of paraffin cracking, naphthene side-chain cracking, aromatic side-chain cracking, ring opening, ring closure, paraffin isomerization, dehydrogenation, and hydrogenation. A molecular model for catalytic reforming was built. On the basis of the simulation model, a process optimization was performed for feed temperature and pressure under constraints such as benzene content, aromatic content, and RON (Research Octane Number) limitations. High RON was contrasted to low benzene and aromatic content requirements. By optimizing and controlling the reaction pathway, we can obtain a final product with the highest profit and appropriate benzene and aromatic contents and RON value. This example shows significant benefits from applying molecular modeling to optimization in the process level. Since gasoline production is related to many different processes such as reforming, FCC, isomerization, alkylation, and so on, more benefits can be obtained by applying molecular modeling to plant-wide optimization.     

Catalytic cracking in presence of an aromatic addition

Fluidized bed catalytic cracking of vacuum gas oil fractions in the presence of extract from phenol purification of heavy lubricating oil fraction as an aromatic addition was investigated. Results show that, at the optimum concentration of the addition, coke formation on the catalyst decreases by 50 to 70% while the content of olefinic hydrocarbons in gasoline decreases, with a corresponding increase in the content of paraffin/naphthene hydrocarbons. The yield of gasoline increases, while its octane number increases by about two units.     

劣质原料催化裂化脱硫降烯烃生产清洁汽油技术

介绍了劣质催化裂化原料的特点,分析了催化裂化汽油清洁化对策,应从提高FCC汽油质量关键应从FCC进料预处理、优化FCC加工过程以及FCC汽油精制等3方面出发．采用有效的降烯烃技术以及选择性加氢和氧化一萃取等脱硫技术对催化裂化汽油进行清洁化处理。认为应注重发展加氢技术,增强加氢在清洁油品生产中的作用;适当减少FCC汽油所占比例,增加异构化油、烷基化油、重整汽油比例,缩小与国外成品油结构组成的差距。     

高标号车用汽油（Ⅲ）调合技术的研究

文章对采用茂名石化生产的重整汽油、催化汽油、芳烃抽余油及MTBE为调合组分,进行高标号车用汽油（Ⅲ）调合技术的研究。结果表明,采用茂名石化生产的重整汽油、催化汽油、芳烃抽余油和MTBE及MMT的情况下,可调制出符合GB17930-2006车用汽油（Ⅲ）93和97号质量标准的车用汽油,加入适量的MMT,辛烷值可达（RON）99以上。     

发展催化重整装置改善我国油品质量

针对我国汽油消耗量快速增长和油品指标日趋严格的现状,从芳烃及衍生物消费、加氢工艺氢源需求的增加等方面探讨了我国发展催化重整装置的重要性.指出制约我国催化重整发展的主要因素是与乙烯争夺原料,石脑油短缺问题.分析研究了扩大和优化催化重整原料来源的途径,以改变重整原料数量不足的局面.催化重整产品需求量的增加和原料供应的改善将使我国催化重整工艺进入一个新的发展时期.     

Improving the yield and quality of reformate via combined application of staged reforming and hydroisomerization

Three process flowsheets combining the processes of catalytic reforming, interstage separation, and reformate hydroisomerization are considered to improve the yield and quality of reformate (i.e., reduce the content of aromatics, including benzene). It is shown that the process flowsheet with the distillation of the intermediate reformate into three fractions (IBP-85°C, 85–150°C, and EBP-150°C) is the best one, since it allows the production of high-octane gasoline compounds with a reduced benzene content (less than 1 wt %) at an appreciable increase in the yield of reformate (up to 4–5 wt %) and its research octane number (RON) (up to 2), in comparison to traditional (fixed-bed) catalytic reforming. Effective catalysts are selected for the reforming and reformate hydroisomerization stages and are used to perform experimental modeling of the considered flowsheets for the combined reforming–hydroisomerization process. The results confirm analytical estimates for the effectiveness of the developed technology.     

用吸附分离技术优化石脑油原料质量的探索

石脑油作为蒸汽裂解工艺的主要原料，其性质直接影响裂解主要产品收率和裂解炉操作周期。石脑油中不同烃类组成的裂解性能存在较大差异。探索试验结果表明：采用吸附分离技术可以做到正构、非正构烷烃的分离，从而优化蒸汽裂解制乙烯和催化重整装置的原料，但需要有足够的石脑油资源和催化重整工艺装置生产能力。     

催化裂化轻汽油醚化工艺中试研究

针对催化裂化汽油烯烃含量高、汽油安定性差的问题,采用催化轻汽油醚化工艺技术,在2 L/h的醚化中试装置上,进行了催化轻汽油醚化工艺研究。研究结果表明:经该工艺技术处理后,可使催化裂化汽油烯烃含量降低8.03～11.68个百分点,RON辛烷值增加0.8～1.2个单位。     

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。     

烃重组汽油与催化重整汽油的PONA分析及其组成对比

烃重组技术和催化重整技术都可以生产高辛烷值汽油调和组分,采用气相色谱PONA分析法对烃重组汽油和催化重整汽油分别进行组成分析,并对数据结果进行对比讨论;PONA分析显示,虽然二者都是芳烃质量分数大于70％的高芳烃含量汽油,但在组成分布上存在明显不同;通过结果判断,烃重组汽油的芳烃集中在C8～C10范围,重整汽油中的芳烃...     

Thermal and catalytic degradation of waste high-density polyethylene (HDPE) using spent FCC catalyst

Thermal and catalytic degradation using spent fluid catalytic cracking (FCC) catalyst of waste high-density polyethylene (HDPE) at 430 °C into fuel oil were carried out with a stirred semi-batch operation. The product yield and the recovery amount, molecular weight distribution and paraffin, olefin, naphthene and aromatic (PONA) distribution of liquid product by catalytic degradation using spent FCC catalyst were compared with those by thermal degradation. The catalytic degradation had lower degradation temperature, faster liquid product rate and more olefin products as well as shorter molecular weight distributions of gasoline range in the liquid product than thermal degradation. These results confirmed that the catalytic degradation using spent FCC catalyst could be a better alternative method to solve a major environmental problem of waste plastics. This paper is dedicated to Dr. Youn Yong Lee on the occasion of his retirement from Korea Institute of Science and Technology.     

High efficient separation of olefin from fluid catalytic cracking naphtha: Separation mechanism and universal simulation method

The fluid catalytic cracking (FCC) naphtha critical component-oriented separation process is an efficient method to produce ultra-low-sulfur (<10 μg/g) gasoline with minimal loss of octane number (<1 RON). However, the product quality is highly dependent on the structure of the components of FCC naphtha. Aromatics and thiophene sulfides without a methyl side chain favor the separation of olefin. The major impulse of olefin separation is the solvent-induced dipole of aromatics or thiophene sulfides, leading to a “Plane-to-Plane” combination between the solvent and aromatics or thiophene sulfides, accompanied by a steric hindrance due to their side chains. This condition resulted in 2–3 times greater θ of benzene and thiophene compared with that of toluene and 3-methylthiophene. In addition, an improved non-random two-liquid model was proposed based on the above results, and a simulation method for FCC naphtha solvent extraction process was established. The calculation results accorded well with industry data.     

基于分子矩阵的炼油过程的全厂模拟

针对复杂的炼油生产过程及其物流成分,采用分子矩阵表征相关的物流分子组成,对催化重整、加氢脱硫、汽油稳定塔和油品调和四个过程建立了基于分子矩阵的过程模型. 通过物性-分子矩阵转换关系可以方便地从已知物流物性计算分子矩阵以及由分子矩阵得到物流物性. 基于分子矩阵的模型计算不仅可以提供比传统虚拟组分模型更为详尽的分子信息,而且可以统一传统建模中不同过程虚拟组分和集总参数之间的差异,将多个过程模型集成实现全厂的模拟.     

我国增产三苯的工艺路线评述

对中国未来的三苯(BTX)市场供求形势进行了分析,同时对传统的芳烃生产工艺(石脑油铂重整、蒸气裂解制乙烯)以及新开发的芳烃生产工艺(链烷烃沸石重整、轻烃芳构化)进行了详细介绍。在此基础上,对我国增产芳烃提出了建议。     

费托蜡催化裂化反应生产清洁汽油的热力学分析

费托蜡主要由链烷烃组成,不含硫、氮等杂原子,是生产清洁汽油的优质原料。由于缺少芳烃和环烷烃,费托蜡催化裂化过程需要强化异构化、芳构化反应以实现降低汽油馏分烯烃含量、保持高辛烷值的目标。对费托蜡为原料的催化裂化反应体系进行热力学分析,重点计算了不同温度下生成汽油馏分主要烃类的反应焓变和反应平衡常数。研究结果表明,以大分子链烷烃为主的费托蜡,其裂化吸热反应焓变约为80 kJ/mol,反应平衡常数随温度的升高而增大,高温有利于一次裂化反应。对于异构化反应,主要是大分子链烷烃裂化为烯烃,再由烯烃分子转化为异构烷烃,因此对于异构化反应,可以通过优化反应器促进汽油烯烃的转化。在考察温度范围内,烯烃环化反应平衡常数随温度升高而减小,环烷烃脱氢芳构化反应平衡常数随温度升高而增大,所以适宜的反应温度是制约进一步增加汽油中芳烃的重要因素。     

石脑油组成结构对乙烯收率的影响

就石脑油组成中直链烷烃含量、异构烷烃含量、环烷烃含量、烷烃正异比等因素与其蒸汽热裂解乙烯收率的关系进行粗略分析.并根据理论分析与实验、生产经验,结合最小二乘法的数学分析方法,在大量试验数据的基础上初步拟合了一些经验方程.这些方程可作为判断石脑油裂解性能优劣和预测石脑油乙烯收率的粗略工具.     

灵活运用各项工艺措施实现清洁汽油的生产

对车用汽油清洁化生产的主要控制难点进行了分析,结合镇海炼化公司的情况,对工业生产中所采取的诸如催化原料脱硫预处理、MIP—CGP改造、应用降烯烃催化剂、调整控制汽油干点、提高重整汽油辛烷值与产量、扩大MTBE产能、重整汽油苯组分抽提、汽油组分资源的调合优化利用等多项清洁汽油生产工艺措施的应用及效果进行了总结与探讨。     

催化裂解石脑油加氢利用路线开发

催化裂解与传统的高温蒸汽裂解相比,通过催化剂降低催化裂解反应活化能和反应温度,除生产乙烯、丙烯和丁烯等主要化工原料外,还副产一定量的轻质芳烃。分析催化裂解石脑油,结果表明,催化裂解石脑油主要为C₅~C₉馏分,芳烃质量分数62.97%,苯、甲苯和二甲苯质量分数54.38%,与全馏分裂解汽油相当,是优质的抽提芳烃原料。提出对原料进行预处理后,经两段加氢、产品抽提芳烃的利用路线,并在试验室采用切割塔及等温床完成对原料的预处理,制取满足两段加氢要求的原料。在一段入口温度(45~55) ℃、反应压力2.8 MPa、氢油体积比100∶1、液时空速1.5 h-1和二段入口温度(250~255) ℃、反应压力2.8 MPa、氢油体积比600∶1和液时空速1.5 h^-1条件下,对一段和二段进行1 000 h的加氢评价试验,结果表明,一段加氢后产品双烯值均＜2.5 g-I·（100g油）^-1,二段加氢产品溴价＜1.0 g-Br·（100g油）^-1,硫含量＜1.0 μg·g^-1,满足芳烃抽提对原料烯烃及硫含量的要求。     

催化裂化汽油脱硫精制技术研究进展

催化裂化汽油是我国车用汽油的主要调和来源,但是硫含量远高于车用汽油质量标准的要求值;因此如何高效降低硫含量是催化裂化汽油精制处理的关键。本文综述了国内外催化裂化汽油脱硫精制生产技术。从选择性加氢脱硫技术（Prime-G⁺技术、SCANfining技术、CD Tech技术、RSDS技术、OCT-M技术和DSO技术）,选择性加氢脱硫耦合辛烷值恢复技术（RIDOS技术和GARDES技术）以及吸附脱硫技术（S-Zorb技术）三方面来阐述国内外催化裂化汽油清洁化技术的原理、特点及其应用。指出深度脱硫和辛烷值保持、烯烃饱和率之间的矛盾,后续研究者仍需在工艺流程改进、工艺条件优化以及新型催化剂开发等方面做出巨大努力。     

高硅ZSM-5在辛烷值助剂中的应用

研究了不同硅铝比ZSM-5分子筛的催化裂化反应性能,结果表明,高硅铝比ZSM-5分子筛能实现提高汽油辛烷值的同时控制液化气产率增幅较小。考察不同硅铝比的高硅ZSM-5分子筛的反应性能,高硅ZSM-5助剂在ACE装置上的评价结果表明,助剂能使液化气和汽油辛烷值小幅增加,同时也能增加汽油中的芳烃含量。随着ZSM-5分子筛硅铝比的增加,助剂控制液化气的性能逐渐增强,但同时提高汽油辛烷值的性能逐渐减弱。在实际应用中,适宜的ZSM-5分子筛硅铝比应根据目标用户的实际情况和要求灵活选择。