C8芳烃中二甲苯和乙苯的分离技术进展

论述了用于C8芳烃中二甲苯异构体以及乙苯分离的各种吸附分离技术进展,对各种工艺和特点以及工业应用状况进行了分析比较.详细介绍了目前国内C8芳烃吸附分离装置中的工业生产状况和面临的问题及挑战.提出应抓紧开发具有自主知识产权的C8芳烃吸附分离技术,尤其是开发一种对乙苯和二甲苯同时具有高选择性、高吸附能力、容易脱附的吸附剂,实现从C8芳烃中同时得到乙苯和二甲苯高纯度产品的目的,打破国外的技术垄断.     

C_8芳烃异构体的分离技术进展

C8芳烃是化工生产中重要的基础原料,二甲苯异构体的分离也一直是分离领域的重要课题之一,文章综合论述了用于二甲苯异构体分离的结晶分离法、吸附分离法、络合萃取法以及目前的研究热点膜分离法,列举了部分已经工业化的生产工艺,并对各种工艺方法和特点进行了分析比较。     

扬子石化开拓聚酯产业链

<正>根据产业链发展需要,该公司研究院对芳烃原料进行优化,开展了混合二甲苯乙苯分离技术研究,初步编制完成20万t工艺包,目前正推进工业化应用。针对公司芳烃二甲苯异构单元乙苯转化率低且增加装置能耗的问题,研究院开展了混合二甲苯中的乙苯分离技术研究,     

对二甲苯装置开工技术分析

对二甲苯芳烃联合装置(以下简称二甲苯装置)是由歧化、异构化、吸附分离和二甲苯分馏四个单元组成。二甲苯装置开工以装置引C8芳烃作为开工起始节点,经历装置各单元升温,改循环,吸附单元相关管线处理,吸附分离装置开工,异构化装置开工以及歧化装置开工,最后以产出达到设计要求的对二甲苯产品作为开工结束节点。文章主要讲述四川石化二甲苯装置开工的基本过程以及在开工过程中所遇到的问题和处理方法。     

C8芳烃中乙苯在纳米HZSM-5沸石上选择性催化裂解

本文采用自装的小型固定床常压反应器为反应器,以纳米HZSM-5沸石为催化剂,对混合C8芳烃中的乙苯选择性催化裂解脱烷基反应进行了研究。结果表明,反应温度对于各种碳八芳烃的异构体互相转化有重要影响。通过实验可知乙苯催化裂解后脱烷基反应的最小温度应是450-480℃左右。高的反应温度有利于提高乙苯转化率,但反应温度过高会导致乙苯侧链裂解,并产生二甲苯脱烷基等副反应。根据钠离子改性和NH3-TPD谱图、吡啶红外光谱表征发现,乙苯分子催化裂解脱烷基反应需要强酸中心。但过强的酸中心可能会加重乙苯侧链裂解反应和二甲苯脱甲基、氢转移等副反应。     

世界芳烃生产技术的发展趋势

分析了近年来国内外聚酯和对二甲苯的供需状况及未来需求发展趋势;介绍了当前芳烃主要生产技术,包括催化重整、芳烃抽提、甲苯歧化与烷基转移、二甲苯异构化和二甲苯分离等;指出了扩大芳烃原料来源、通过催化剂的改进提高甲苯歧化过程的对二甲苯选择性、提高C9及以上重芳烃处理能力、提高乙苯转化率等将是未来芳烃技术的主要发展方向。     

烃类异构化分子筛催化剂的反应性能研究

合成了具有EUO拓扑结构的FZ-10分子筛,并对其进行改性研究,考察了催化剂酸强度分布和酸量对二甲苯异构反应性能的影响规律.结果表明:中等强度B酸中心数目较多的FCZ-102催化剂表现了更好的C8芳烃收率和乙苯转化率,当二甲苯异构体接近热力学平衡组成、乙苯转化率为27％时,C8芳烃收率达到98％以上.     

模拟移动床技术及其在石化领域中的研究进展

本文介绍了模拟移动床技术的工作原理及其在石化领域中分离二甲苯、乙苯、芳烃及正构烷烃分离等方面的应用。     

碳八芳烃分离制乙苯及苯乙烯工艺技术研究

一、前言炼厂铂重整—加氢联合装置是由预分馏和重整抽提,芳烃分离及柴油加氢精制四大部份组成。装置的芳烃分离只分出苯、甲苯、混合二甲苯。而碳八芳烃中的乙苯、混合二甲苯中的邻二甲苯,对二甲苯、间二甲苯均未进行分离,这些芳烃是重是的化工原料。乙苯脱氢可以制取苯乙烯。而聚苯乙     

二乙苯溶液中C_8芳烃的吸附动力学性质

本文以连续流动单管实验装置,研究了C_8芳烃的单溶质在二乙苯溶液中的液相吸附动力学性质.测定了在170℃下对二甲苯、邻二甲苯、乙苯在二乙苯溶液中各系统的穿透曲线.根据穿透曲线以及有关的参数,分析和计算了在二乙苯溶液中C_8芳烃吸附的一些性质.并且研究和确定了本系统的吸附控制机理.     

PAI-01型C_8芳烃异构化催化剂的工业应用及再生

介绍了PAI-01型C8芳烃异构化催化剂在辽阳石化公司25万吨/年对二甲苯芳烃联合装置异构化单元上替代I-300催化剂的工业应用和再生情况。在乙苯脱烷基型异构化装置上换装了乙苯转化型催化剂,对装置进行改造,增加一轻烃分离塔。结果表明,PAI-01型催化剂的技术指标达到国际先进水平。催化剂应用满三年后,进行了器内再生,再生后催化剂活性可达到新鲜催化剂水平。     

High suppression of the formation of ethylbenzene in benzene alkylation with methanol over ZSM-5 catalyst modified by platinum

The generation of ethylbenzene is difficult to be avoided in benzene alkylation with methanol over ZSM-5 catalysts to produce toluene and xylene. Moreover, the separation or removal of ethylbenzene from C8 aromatic yet remains as a major challenge. In this study, the effect of Pt addition on the catalytic performance of ZSM-5 for benzene alkylation was investigated. It was found that the presence of a small amount of Pt in ZSM-5 catalyst would largely suppress the formation of ethylbenzene and extend the life-span of the catalyst, which was mainly due to the hydrogenation of ethylene into ethane on Pt particles.     

西藏麝香合成新工艺

以催化重整C9芳烃分离装置分离出均三甲苯、偏三甲苯后的副产品重组分溶剂(169～178℃馏分)—混合C9芳烃为原料,其中含连三甲苯40%～50%,以三氯化铝为催化剂与异丁烯进行烷基化反应,合成出5 叔丁基 1,2,3 三甲基苯中间体,经蒸馏后,用混酸进行硝化反应得到西藏麝香。本方法不但具有工艺路线简单,生产成本低的特点,同时也解决了富集连三甲苯的利用问题。     

Separation of Aromatic Solvents from the Reformate Fraction of an Oil Refining Process using Extraction by a Designed Ionic Liquid

Separation of aromatic solvents, from mixtures containing aliphatic solvents as the major fraction, is important, inter alia, for its reuse in industrial processes. This report deals with the use of a designed and synthesized ionic liquid (N-butyl-N-methyl-2-oxopyrrolidonium bromide) for the separation of benzene, toluene, ethylbenzene, and xylene (BTEX), including all the isomers of xylene. For comparison purposes, a previously-used ionic liquid (1-ethyl-3-methylimidazolium ethyl sulphate) was also synthesized and used. The experimental parameters established for the separation/extraction of the mixed standard of BTEX were applied to the separation/extraction of the components of BTEX from the reformate fraction of an oil refining process. The method was tested for BTEX components varying in concentration from 0.5 to 10%. The results show that the new ionic liquid gives higher extraction efficiency than the one used in a previous project. The results are as good as that obtained by a local oil refinery which used a conventional solvent. Furthermore, the results reveal a general increase in percentages extracted in the following order: m-xylene < p-xylene ? o-xylene < ethyl benzene < toluene < benzene.     

新型碳八芳烃异构化催化剂的制备及其性能

选用独特结构的分子筛材料为酸性组元,制备了新型碳八（C8）芳烃异构化催化剂,并对该催化剂的异构化能力进行了研究。选取目前工业用催化剂作为对比催化剂,采用相同的反应原料,在各自最佳的反应条件下,与新型催化剂进行比较。实验结果表明,随着原料的不同,在反应产物中,新型催化剂反应中的对二甲苯在二甲苯中的浓度为19.06%～24.14%,乙苯转化率为32.07%～41.50%,C8烃收率为97.08%～99.11%,远高于对比催化剂;同时,甲苯含量为0.26%～1.20%,重芳烃含量为0.22%～0.62%,远低于对比催化剂。同对比催化剂相比,新型催化剂具有较高的异构化活性和选择性,能在较高的空速下运行。     

混合C_9芳烃与异丁烯合成西藏麝香的工艺研究

以催化重整C9芳烃分离装置分离出均三甲苯、偏三甲苯后的副产品重组分溶剂(169～178℃馏分)———混合C9芳烃为原料,其中含连三甲苯40%～50%,以三氯化铝为催化剂与异丁烯进行烷基化反应,合成出5 叔丁基 1,2,3 三甲基苯中间体,经蒸馏后,用混酸进行硝化反应得到西藏麝香。本方法不但具有工艺路线简单,生产成本低的特点,同时也解决了富集连三甲苯的利用问题。     

Preparation of nano-zeolite tubular membrane for ethylbenzene separation from ternary mixed xylene by microwave functional coating method

The ethylbenzene separation from mixed xylene is one of the critical issues in the chemical industry. In this study, separation of ethylbenzene from ternary xylene mixtures system [ethylbenzene (EB), para-xylene (PX) and meta-xylene (MX)] was performed using a nano-zeolite coated tubular membrane system. Nano-zeolite membranes with different Si/Al ratios (Si/Al = 30, 100 and ∞) were prepared by a microwave hydrothermal method and the separation performance was compared. MFI-type nano-zeolite membranes were synthesized on alumina tubes from the randomly oriented seed layers by dip coating and functional coating using 3-chloropropyltrimethoxysilane, respectively. After the microwave-assisted secondary growth, it was observed that thinner layers of nano-zeolites were prepared by functional coating (3–4 μm) compared to the typical dip coating (6–8 μm). Ethylbenzene separation tests were performed using a comparatively high EB-containing ternary mixture feed (EB/PX/MX = 80/5/15 molar ratio). The silicalite-1 (Si/Al ratio = ∞) membrane with a functional layer shows the best ethylbenzene separation factor of 3.11 from the high EB-containing ternary mixture feed (ethylbenzene flux: 1,010.6 mol/m² s Pa ×10^?10).     

碳八芳烃异构体分离技术评述

介绍了碳八芳烃异构体工业分离技术的现状、对二甲苯分离技术的新发展。评述了择形催化生产对二甲苯的技术、利用结晶处理高浓度对二甲苯原料、变压吸附低成本浓缩对二甲苯技术、分子筛膜分离对二甲苯等。     

Effect of Electrolyte and Temperature on Volatile Organic Compounds Removal from Wastewater Using Aqueous Surfactant Two-Phase System of Cationic and Anionic Surfactant Mixtures

Abstract

Benzene, toluene, ethylbenzene, and xylene are frequently observed contaminants in industrial wastewaters causing concerns about environmental and health effects. An aqueous surfactant two-phase (ASTP) extraction system using mixtures of cationic and anionic surfactants have been shown to be a promising surfactant-based separation technique to concentrate solutes such as proteins and dyes from aqueous solution. A phase separation of a surfactant solution occurs at certain surfactant compositions and concentrations, forming two isotropic phases. One is rich in surfactant aggregates (surfactant-rich phase) and the other is lean in surfactant aggregates (surfactant-dilute phase). Most of the organic contaminants tend to solubilize and concentrate in the surfactant-rich phase, leaving the surfactant-dilute phase containing only small amounts of contaminants as remediated water. The effect of NaCl addition on the critical micelle concentration (CMC) and the extraction ability of ASTP formed by mixtures of cationic surfactant (dodecyltrimethylammonium bromide; DTAB) and anionic surfactant (alkyl diphenyloxide disulfonate; DPDS) at 50 mM total surfactant concentration with a 2:1 molar ratio of DTAB:DPDS was investigated; the CMC of the mixture slightly decreases with increasing NaCl concentration. The extraction and preconcentration of benzene are greatly enhanced by added NaCl. The higher the degree of hydrophobicity of contaminants, the greater the extraction into the surfactant-rich phases. At 1.0 M NaCl addition, about 95% of xylene, 92% of ethylbenzene, 90% of toluene, and 79% of benzene are extracted into the surfactant-rich phase within a single stage extraction and the contaminant partition ratios can be as high as 395 for xylene, 273 for ethylbenzene, 206 for toluene, and 84 for benzene, which are greater than those obtained from the conventional ASTP extraction system using nonionic surfactants.     

Development of a test method using a VOC analyzer to measure VOC emission from adhesives for building materials

A volatile organic compound (VOC) analyzer is a portable device to measure the four main aromatic hydrocarbon gases: toluene, ethylbenzene, xylene and styrene. With the VOC analyzer, a semiconductor gas sensor eliminates the need for the carrier gas which is required for conventional gas chromatography. In addition, since the semiconductor gas sensor is supersensitive to gas components, it is not necessary to use a conventional gas concentrator or other complicated equipment. Compared with other measurement methods, the VOC analyzer is useful for measuring toluene, ethylbenzene, xylene and styrene in new buildings because of its ease in obtaining field results and repeating the test. For easy, fast and economic testing of total (TVOC) emission from adhesives used for building materials, we developed a test method using the VOC analyzer and compared its measurement of VOC emissions from building materials such as adhesives, paints and wood-based panels with that of the 20-l chamber method, which is the standardized test method in Korea. There was a good correlation between the TVOC emission concentrations determined by the VOC analyzer and the TVOC emission factor (EF) by the 20-l chamber. Based on this good correlation, the VOC analyzer is expected to gain widespread use in the manufacturing field application where a quick and easy test for VOC emission from adhesives for building materials is required. Furthermore, the VOC analyzer offers the potential to become an easier, faster and more economical technique than the currently used standard methods.