采用分离集成技术从碳十芳烃中提取均四甲苯

采用萃取精馏和连续多级结晶相结合的分离集成技术从C_(10)芳烃中提取均四甲苯。选择甘油为萃取剂,考察实际塔板数、回流比、萃取剂与原料液的体积比(溶剂比)、进料量、结晶温度、结晶时间、抽滤时间等因素对分离均四甲苯的影响。萃取精馏条件:实际塔板数为106块、原料进料位置为第75块塔板、萃取剂进料位置为第5块塔板、溶剂比为1.0、回流比为4、原料进料量为2 mL/min,在此条件下,萃取塔顶馏分中均四甲苯的质量分数为42.7%,收率达到98.4%。连续多级结晶条件:结晶温度-6℃、结晶时间5 h、抽滤时间20 min,在此条件下,可将均四甲苯质量分数从42.7%提纯到99.18%,收率为90.95%。     

大型对二甲苯装置的节能设计与优化

以某企业1.50 Mt/a对二甲苯装置的设计为例,综合分析该装置中各单元的能耗分布及采用节能设计对装置能耗的影响;结合对二甲苯装置的特点,深入探讨提高加热炉热效率、优化低温热利用方案等措施对降低装置能耗的重要性。结果表明：举例装置基于“95+”的技术改进加热炉设计,最大限度地回收烟气余热,使加热炉热效率超过95%,明显高于常规设计值(92%),可节省燃料费用2 340万元/a;通过采用低温热发生蒸汽技术,1.2 MPa蒸汽产出量为89.2 t/h, 0.6 MPa蒸汽产出量为254.2 t/h,而且余热采用蒸汽压缩可得1.8 MPa蒸汽,满足多个蒸汽用户需求;通过采用低温热制热水,可得110℃热水约746.2 t/h,采用先进热水制冷等技术制备的冷冻水除满足装置自身需求外,还可服务多个用冷装置;通过整体优化设计,使对二甲苯分离、二甲苯异构化、二甲苯分馏等单元的产品能耗仅为5 190.9 MJ/t,与同类装置相比大幅降低,达到国内领先水平。     

Production of benzene,toluene, and xylenes from natural gas via methanol: Process synthesis and global optimization

A systematic global optimization‐based process synthesis framework is presented to determine the most profitable processes to produce aromatics from natural gas. Several novel, commercial, and/or competing technologies are modeled within the framework, including methanol‐to‐aromatics, toluene alkylation with methanol, selective toluene disproportionation, and toluene disproportionation and transalkylation with heavy aromatics, among others. We propose a stand‐alone chemicals facility: the main products are aromatics with allowable by‐products of gasoline, liquefied petroleum gas, and electricity. Several case studies are discussed that produce varying ratios of para‐, ortho‐, and meta‐xylene across multiple refinery capacities. The results indicate that utilizing natural gas for the production of aromatics is profitable with net present values as high as $3800 MM dollars and payback periods as low as 6 years. The required investment for these refineries represents as much as a 65% decrease compared to published estimates of similar coal‐based capacity plants. © 2016 American Institute of Chemical Engineers AIChE J, 62: 1531–1556, 2016     

优化工艺参数 降低芳烃抽提装置能耗

对芳烃联合装置进行简要概述,结合装置生产实际,通过工艺调整,生产调整等优化运行方案,降低了环丁砜抽提单元的蒸汽消耗,并能很好的保证抽余油及抽出物产品的质量。     

均四甲苯的生产方法

均四甲苯是一种重要的有机化工原料,主要用于生产均苯四甲酸二酐,近几年均苯四甲酸二酐的用途不断扩大,均四甲苯需要量也大幅上升。本文综述了C10重芳烃分离法、四甲苯异构化和偏三甲苯甲醇烷基化三种方法。认为在C10芳烃资源较集中的地区,以C10芳烃为原料,生产均四甲苯。有工艺流程短,投资少,成本低,见效快等优点。     

减二线油制备环保型橡胶填充油的实验研究

以滨化减二线油为原料,采用二次溶剂抽提工艺和催化加氢-溶剂抽提联合工艺制备环保型橡胶填充油。结果表明,二次溶剂抽提工艺在抽提温度50℃,剂油比1.5∶1时,可得到PCA为2.84%,C A值为10.76%,收率61.83%的环保型橡胶填充油。催化加氢-溶剂抽提联合工艺在催化加氢反应温度320℃,氢初压7 MPa,加氢时间2 h,抽提温度70℃,剂油比1.5∶1条件下,可得到抽余油PCA为2.03%,C A值为15.21%,收率75.20%的环保型橡胶填充油。催化加氢-溶剂抽提联合工艺的产品性质更优,收率更高。     

An Approximate Hückel Total π-Electron Energy Formula for Benzenoid Aromatics: Some Amendments

Abstract

Some results, recently reported by L. Türker (Polycyclic Aromat. Compd. 4 (1994) 107–114), are shown to be erroneous and amendments are offered.     

塑料洞洞鞋中可能存在的有毒化学物质危害分析及其对策

通过对我国洞洞鞋中有毒有害化学物质现状的调查,并结合流通领域样品检测数据,分析了洞洞鞋中可能存在的有毒有害化学物质及其对人体潜在危害。通过国内外的有关洞洞鞋中邻苯二甲酸酯、多环芳烃和可迁移重金属限量标准的对比分析,发现我国标准在限制洞洞鞋中有毒有害化学物质的方面滞后于欧美地区,缺乏强制性的洞洞鞋标准。建议相关部门完善洞洞鞋的相关标准,加强对企业原料质量和生产过程的监管,提高洞洞鞋产品质量。     

Exergy and exergoeconomic analyses for integration of aromatics separation with aromatics upgrading

Methanol to aromatics produces multiple products, resulting in a limited selectivity of xylene. Aromatics upgrading is an effective way to produce more valuable xylene product, and different feed ratios generate discrepant product distributions. This work integrates the aromatics separation with toluene disproportionation, transalkylation of toluene and trimethylbenzene, and isomerization of xylene and trimethylbenzene. Exergy and exergoeconomic analyses are conducted to give insights in the splitting ratios of benzene, toluene and heavy aromatics for aromatics upgrading. First, a detailed simulation model is developed in Aspen HYSYS. Then, 300 splitting ratio sets of benzene and toluene for conversion are studied to investigate the process performances. The results indicate that there are different preferences for the splitting ratios of benzene and toluene in terms of exergy and exergoeconomic performances. The process generates lower total exergy destruction when the splitting ratio of toluene varies between 0.07 and 0.18, and that of benzene fluctuates between 0.55 and 0.6. Nevertheless, the process presents lower total product unit cost with the splitting ratio of toluene less than 0.18 and that of benzene fluctuating between 0.44 and 0.89. Besides, it is found that distillation is the biggest contributor to the total exergy destruction, accounting for 94.97%.