萃取精馏法生产均三甲苯的平衡数据测定及模拟

以邻苯二甲酸二丁酯(DBP)为萃取精馏溶剂,测定了邻甲乙苯-均三甲苯-偏三甲苯体系的二元及三元汽液平衡数据;编程关联了Wilson模型参数;采用物料平衡三对角矩阵法对萃取精馏过程进行了模拟,得出了萃取精馏塔的最佳操作条件,为萃取精馏法生产均三甲苯提供了基础数据.     

C9芳烃中均三甲苯与邻甲乙苯的分离研究

介绍了均三甲苯分离技术的新发展，研究开发了一种新工艺，以叔丁醇为烷基化剂，无水三氯化铝为催化剂，通过傅-克烷基化反应将邻甲乙苯转化成沸点较均三甲苯高的重组分，使二者能通过常规精馏的方法得以有效地分离。研究了反应温度、原料配比、催化剂用量等反应条件对烷基化反应的影响，烷基化反应的最佳工艺条件为室温、反应时问2～4h、C9芳烃与烷基化剂(叔丁醇)及催化剂的摩尔配比为1：1：0．4，可使邻甲乙苯100%转化，而均三甲苯损失率小于2％。     

从C9芳烃中分离制备均三甲苯

评述了从C9芳烃混合物中分离制备均三甲苯的几种方法，并研究开发了一种新工艺，该工艺涉及的所有反应均在常温常压下进行，通过烷基化反应将C9芳烃混合物中与均三甲苯沸点极为接近的邻甲乙苯除去，再经过精馏可以获得98％以上的高纯均三甲苯。     

氯代烷对富集均三甲苯的精制

采用反应分离方法，用氯代烷对富集均三甲苯进行了精制。在选定催化剂和反应温度、反应时间后，当氯代烷与甲乙苯的摩尔比为1.4时，氯代烷对富集均三甲苯的精制起到了较佳的作用，甲乙苯的转化率超过99％，也使偏三甲苯高效异构化均三甲苯，使均三甲苯的产率在116％以上，反应液中均三甲苯与C9芳烃的质量比超过98.9％。     

均三甲苯生产与分离技术新进展

本文评述了均三甲苯生产技术的新进展，重点介绍了作者最近开发的通过偏三甲苯异构化和烷基化反应生产高纯均三甲苯联产均四甲苯的新工艺。该工艺已实现年产600吨均三甲苯工业化生产，产品纯度达98．5％。它是目前国内较先进的均三甲苯、均四甲苯生产技术，具有以下优点：采用异构化和烷基化相结合的方法既可消除甲乙苯的累积，又可保证均三甲苯和均四甲苯的产量和质量；采用变压强－塔顶累积联合操作法进行精馏分离可显著提高分离效率、缩短操作周期、 降低能耗与生产成本，是对传统分批精馏操作的有效改进。     

偏三甲苯生产均三甲苯工艺

在偏三甲苯异构化生产均三甲苯的过程中 ,虽然反应液中均三甲苯含量较高 ,但甲乙苯的累积使该过程的工业化难度大 ,生产成本高 .采用独特的异构化和烷基化反应联合工艺 ,通过烷基化有效抑制甲乙苯的累积 ,其副产品四甲苯用作异构化的原料以抑制歧化副反应 ,而异构化可弥补烷基化中均三甲苯含量低的缺陷 ,从而有效地实现均三甲苯的工业化 ,生产成本大幅度降低 .研究了工艺条件对反应的影响 ,找到了最佳的工艺条件 .目前 ,此工艺已实现了年产 6 0 0t纯度为 98.5 %的均三甲苯的工业化生产     

均三甲苯工业化生产工艺

综述了生产均三甲苯的各种生产工艺,指出其优缺点和工业化价值.主要介绍了使用偏三甲苯烷基化和异构化生产均三甲苯联产均四甲苯的工艺,该工艺有效抑制甲乙苯的累积,实现了高纯均三甲苯的工业化生产.     

异丁烯烷基化法制均三甲苯的研究

主要研究了以石油工业中C9芳烃精馏后的富均三甲革馏分为原料、异丁烯为烷基化剂,采用液相烷基化法制备高纯均三甲苯的工艺条件.使用异丁烯法在一次烷基化后均三甲苯含量可以达到70%以上,通过精馏去除重组分后,进行二次烷基化反应,均三甲苯的含量可达到94%以上,同时更彻底的消除了沸点附近的邻甲乙苯.然后通过精馏得到工业要求的含量为98.5%的高纯均三甲苯.     

C9芳烃催化烷基化法生产高纯度均三甲苯

以富集均三甲苯(均三甲苯含量≥35％)为原料，采用c。芳烃与丙烯进行催化烷基化反应，再对反应产物进行精馏获得高纯度均三甲苯。通过对均三甲苯装置进行改造设计和工艺优化，提高了产品的质量。均三甲苯产品纯度≥99％，偏三甲苯含量≤0．3％。     

甲醛+1,3,5-三聚甲醛+硫酸+水体系汽液相平衡实验和理论研究

工业上利用甲醛水溶液在硫酸催化下的反应精馏工艺生产1,3,5-三聚甲醛，因此，1,3,5-三聚甲醛生产工艺的优化和新型催化剂的开发受到了广泛关注。这需建立反应体系的汽-液相平衡模型，研究1,3,5-三聚甲醛合成过程中催化剂可能发挥的多重作用。为此，测定了(甲醛+1,3,5-三聚甲醛+硫酸+水)体系的汽-液相平衡数据，采用扩展型UNIFAC模型对汽-液相平衡数据进行了关联，确定了模型参数，并对该体系进行了系统的计算，揭示了硫酸催化剂在该反应精馏工艺中的三重作用。上述成果对优化1,3,5-三聚甲醛生产工艺和开发1,3,5-三聚甲醛新型催化剂具有重要意义。     

进口重芳烃宽馏分生产偏三甲苯与富集均三甲苯

重芳烃分离装置是为分离重整装置二甲苯塔塔底产出的碳九芳烃而设计的。为弥补原料不足,加工组分和馏程变化较大的、以碳九、碳十芳烃为主要成分的重芳烃宽馏分进口原料,经方案选择、工艺模拟计算及流程改进,成功地生产了偏三甲苯与富集均三甲苯工业产品。     

精制均三甲苯的进展

总结了近年来均三甲苯精制的方法：如萃取精馏法、反应分离法、异构化分离法、烷基化分离法等,比较各种方法的优缺点,提出采用萃取精馏法精制均三甲苯,不仅工艺简单、投资少,而且产品纯度高,为工业化和进一步研究提供了理论依据。     

环丁砜萃取精馏提纯连三甲苯的实验和模拟

针对混合C₉芳烃原料中沸点接近、分离困难的连三甲苯-茚满物系,以环丁砜为萃取剂进行了萃取精馏分离提纯实验,并采用Aspen Plus化工流程模拟软件对萃取精馏工艺过程进行了模拟研究,萃取精馏实验数据与模拟结果吻合较好,相对偏差小于5%。结合萃取精馏实验和流程模拟考察了萃取精馏塔的理论塔板数、溶剂比（萃取剂与原料的质量比）、回流比以及原料和萃取剂的进料位置等因素对分离效果的影响规律。结果表明,环丁砜萃取精馏提纯连三甲苯较适宜的工艺条件是：萃取精馏塔的理论塔板数为60~65、溶剂比为5~7、回流比为3~4、原料的进料位置为第34~36块板、萃取剂的进料位置为第8~10块板,在此条件下,塔顶可获得高纯度的连三甲苯产品,其质量分数可达99%以上,回收率可达93%以上。     

重芳烃分离填料塔结构研究与工业应用

鉴于1,2,4-三甲基苯装置原工艺流程存在偏三甲苯产品收率与纯度低、装置处理量小等缺点,对三甲苯填料塔的塔 内件结构进行研究与改造设计,并新上1台预分馏塔,将原预分馏塔用作偏三甲苯精馏塔,原偏三甲苯精馏塔用作富集均三甲 苯精馏塔。改造后偏三早苯产品收率由37.77％提高到96.39％,产量由原来的3 961.6 t／a提高到14 963.2t／a。     

A pillared-layer metal-organic framework for efficient separation of C3H8/C2H6/CH4 in natural gas

Metal-organic frameworks (MOFs) have great potentials as adsorbents for natural gas purification. However, the trade-off between selectivity and adsorption capacity remains a challenge. Herein, we report a pillared-layer metal-organic framework Ni(HBTC)(bipy) for efficiently separating the C₃H₈/C₂H₆/CH₄ mixture. The experimental results show that the adsorption capacity of C₃H₈ and C₂H₆ on Ni(HBTC)(bipy) are as high as 6.18 and 5.85 mmol·g^-1, while only 0.93 mmol·g^-1 for CH₄ at 298 K and 100 kPa. Especially, the adsorption capacity of C₃H₈ at 5 kPa can reach an unprecedented 4.52 mmol·g^-1 and for C₂H₆ it is 1.48 mmol·g^-1 at 10 kPa. The ideal adsorbed solution theory predicted C₃H₈/CH₄ selectivity is as high as 1857.0, superior to most of the reported materials. Breakthrough experiment results indicated that material could completely separate the C₃H₈/C₂H₆/CH₄ mixture. Therefore, Ni(HBTC)(bipy) is a promising material for separation of natural gas.     

Effects of water on steam rectification in a packed column

The effects of water on steam rectification, i.e., multi-stage saturated steam distillation, were investigated in a packed column. N-octane-p-xylene and 1,3,5-trimethylbenzene-1,2,4-trimethylbenzene were used as test systems. Both binary systems are nearly ideal systems and insoluble in water, thus the effects of water in steam rectification can be clearly and definitely revealed. Such unpolar organic liquid is named as “oil”. The water/oil at column top can be separated and refluxed at different ratio. Compared with conventional rectification, there are some peculiar phenomena in steam rectification. Water greatly enhances the flooding vapor velocity of the rectification, in addition, water plays a predominant role in pressure drop of the packed bed near flooding point. It is clear that liquid water in the packed bed can promote mass transfer of steam rectification, especially for materials with higher viscosity. In a word, steam rectification can be operated at low temperature with good mass transfer.     

Boosting selective C2H2/CH4, C2H4/CH4 and CO2/CH4 adsorption performance via 1,2,3-triazole functionalized triazine-based porous organic polymers

Nitrogen-rich porous organic polymers have shown great potentials in gas adsorption/separation, photocatalysis, electrochemistry, sensing and so on. Herein, 1,2,3-triazole functionalized triazine-based porous organic polymers (TT-POPs) have been synthesized by the copper-catalyzed azide-alkyne cycloaddition (Cu-AAC) polymerization reactions of 1,3,5-tris(4-azidophenyl)-triazine with 1,4-diacetylene benzene and 1,3,5-triacetylenebenzene, respectively. The characterizations of N₂ adsorption at 77 K show TT-POPs possess permanent porosity with BET surface areas of 666 m²·g^-1 (TT-POP-1) and 406 m²·g^-1 (TT-POP-2). The adsorption capacities of TT-POPs for CO₂, CH₄, C₂H₂ and C₂H₄, as well as the selective separation abilities of CO₂/N₂, CO₂/CH₄, C₂H₂/CH₄ and C₂H₄/CH₄ were evaluated. The gas selective separation ratio of TT-POPs was calculated by the ideal adsorbed solution theory (IAST) method, wherein the selective separation ratios of C₂H₂/CH₄ and C₂H₄/CH₄ of TT-POP-2 was 48.4 and 13.6 (298 K, 0.1 MPa), which is comparable to other adsorbents (5.6-120.6 for C₂H₂/CH₄, 10-26 for C₂H₄/CH₄). This work shows that the 1,2,3-triazole functionalized triazine-based porous organic polymer has a good application prospect in natural gas purification.     

Highly selective separation of propylene/propane mixture on cost-effectively four-carbon linkers based metal-organic frameworks

The separation of propylene and propane is an important but challenging process, primarily achieved through energy-intensive distillation technology in the petrochemical industry. Here, we reported two natural C₄ linkers based metal–organic frameworks (MIP-202 and MIP-203) for C₃H₆/C₃H₈ separation. Adsorption isotherms and selectivity calculations were performed to study the adsorption performance for C₃H₆/C₃H₈ separation. Results show that C₃H₆/C₃H₈ uptake ratios (298 K, 100 kPa) for MIP-202 and MIP-203 are 2.34 and 7.4, respectively. C₃H₆/C₃H₈ uptake ratio (303 K, 100 kPa) for MIP-203 is up to 50.0. The mechanism for enhanced separation performance of C₃H₆/C₃H₈ on MIP-203 at higher temperature (303 K) was revealed by the in situ PXRD characterization. The adsorption selectivities of C₃H₆/C₃H₈ on MIP-202 and MIP-203 (298 K, 100 kPa) are 8.8 and 551.4, respectively. The mechanism for the preferential adsorption of C₃H₆ over C₃H₈ in MIP-202 and MIP-203 was revealed by the Monte Carlo simulation. The cost of organic ligands for MIP-202 and MIP-203 was lower than that of organic ligands for those top-performance MOFs. Our work sets a new benchmark for C₃H₆ sorbents with high adsorption selectivities.     

Separation of Trimethylbenzene Isomers on Molecular Sieves 13X in High Pressure Carbon Dioxide

Abstract

An experimental study of the separation of 1,2,4-and 1,3,5-trimethylbenzenes from a mixture containing the weight composition 56% 1,2,4-trimethylbenzene and 44% 1,3,5-trimethylbenzene on molecular sieves 13X in high pressure carbon dioxide was performed. For a pulse of 1.18 cm³ of trimethylbenzene isomers and 40 g of molecular sieves 13X, the effects of pressure, temperature, and flow rate on separation effectiveness were examined. The results indicated that the most appropriate operating conditions for obtaining a higher recovery of each isomer with a purity of at least 98% and a shorter mean retention time for 1,3,5-trimethylbenzene were a temperature of around 363 K, a pressure of 74.8 atm, and a flow rate of 15.0 cm³/min.