混相反应—催化蒸馏工艺生产MTBE的质量控制

从混相反应—催化蒸馏工艺生产MTBE的过程及原理出发,对反应及分离工序的控制因素分析,通过生产实践证明采取降低反应温度,调整醇烯比等方法,可提高产品转化率,抑制杂质组分生成,从而提高MTBE产品质量。     

影响醚化反应因素的探讨

主要介绍了醚化反应的机理,明确了反应温度、反应压力、醇烯比、空速等参数对异丁烯与甲醇反应生成甲基叔丁基醚(MTBE)这一个可逆放热反应的影响。从而优化了操作条件,该善了MTBE产品及醚后碳四产品质量、降低了生产成本、提高了经济效益。     

利用Aspen Plus模拟工业MTBE装置

MTBE(甲基叔丁基醚)是一种提高汽油辛烷值的添加剂和化工原料。工业上要提高MTBE产量、减少装置能耗,就需要探索最优的操作条件。文中运用Fortran语言编写反应动力学程序,并嵌入Aspen Plus中来模拟复杂的工业MTBE装置,模拟结果与工业装置较好吻合。通过模拟结果分析了反应精馏塔的温度、组成分布和MTBE生成速率,同时考察改变工艺参数对产品MTBE纯度和异丁烯转化率的影响。优化后MTBE产品质量分数高达98.5%,异丁烯转化率为99.7%。     

醚化反应器和催化蒸馏塔腐蚀原因分析及预防

从MTBE装置的生产过程的特点及基本原理出发,通过对反应器和分馏塔的控制因素进行取样和实验分析研究,并结合实际数据,找出造成MTBE装置醚化反应器和催化蒸馏塔腐蚀的主要原因,提出了严格控制碳四原料,控制好反应的操作指标,抑制杂质组分生成的建议,从而为提高MTBE的产品质量提供可借鉴的经验。     

MTBE装置运行中催化剂活性变化趋势分析及应对措施

文章介绍了大孔径强酸性阳离子交换树脂催化剂在醚化装置上的使用情况,通过开车初期、正常生产及后期装置的运行状况,分析了催化剂活性下降原因,及MTBE产品纯度和异丁烯转化率下降的原因,通过提高反应进料温度、催化蒸馏塔反应压力,控制原料碳五含量及调整醇烯比等优化操作措施,有效地延长了催化剂使用寿命,提高了MTBE纯度和异丁烯的转化率。     

MTBE装置高附加值产品优化研究

甲基叔丁基醚(MTBE)具有广泛的应用价值,新形势下如何生产装置高附加值产品并提高装置效益是值得研究的课题。通过采用精益六西格玛方法研究MTBE装置反应特点,提出降低MTBE碳四馏分中碳五馏分含量,提高高附加值产品产量的方案措施,为企业MTBE装置生产高附加值产品提供技术支持,也为同类装置提质增效提供参考和借鉴。     

甲基叔丁基醚裂解制异丁烯技术进展

介绍了甲基叔丁基醚(MTBE)裂解制异丁烯(IB)催化剂和生产工艺的研究进展,对不同的催化剂和生产工艺进行了分析。结果表明,开发活性高、选择性好的MTBE裂解制IB催化剂,最大限度地提高MTBE转化率、降低副反应深度,不断改进反应器的结构、优化反应操作条件,根据不同的下游产品选择合理的工艺流程是MTBE裂解制IB工艺的主要研究方向。就合理选择MTBE裂解制IB工艺流程提出了相应的建议。     

液化气C4组分异构化研究及应用

在实际生产过程中,MTBE装置加工后的剩余C₄中含有大量非活性C₄烯烃,该部分烯烃随着液化气作为产品进行销售,对于液化气中的C₄造成浪费。提出将MTBE装置剩余C₄引入汽油加氢醚化装置异构化反应器进行异构化反应,将剩余C₄中的非活性烯烃转化为活性烯烃,再将异构化产物送至MTBE装置原料缓冲罐中作为MTBE装置原料进行反应。通过调研后得出,异构化反应器催化剂对剩余C₄中的非活性烯烃转化率可达30%,异构化反应产物与进料对比,异丁烯含量上升约3%,可有效提高MTBE装置产品产量。     

硼改性沸石上甲基叔丁基醚气相合成反应

考察了HZSM-5、HY和Hβ等沸石催化剂上气相合成甲基叔丁基醚(MTBE)的反应性能,发现Hβ沸石对MTBE的合成具有比其它沸石更高的活性和选择性.研究了加入粘合剂后催化剂活性和选择性的变化.通过对催化剂的酸性表征,认为L酸中心对MTBE合成具有重要作用.在此基础上,设计制备出了硼改性B2O3/Hβ-Al2O3催化剂,使MTBE产率明显提高,选择性接近100%.讨论了反应性能与催化剂表面酸性的关系.     

优化工艺操作 提高MTBE产品质量

介绍了兰州石化MTBE/丁烯-1装置醚化反应原理,主要反应控制参数,分析了影响MTBE产品质量的原因,并实施了有效措施。     

Fe-zeolites as catalysts for chemical oxidation of MTBE in water with H2O2

The heterogeneous catalytic wet oxidation of methyl tert-butyl ether (MTBE) with hydrogen peroxide, catalyzed by the iron-containing zeolites Fe-ZSM5 and Fe-Beta, was studied at ambient conditions and pH 7. The kinetics of MTBE degradation could be well-fitted to a pseudo-first-order model. Using Fe-ZSM5, the dependence of the reaction rate constant on hydrogen peroxide and catalyst concentration was determined. Furthermore, the formation and oxidation of tert-butyl alcohol and tert-butyl formate as intermediates of MTBE oxidation were studied. A comparison of the reaction rates of MTBE, trichloroethylene and diethyl ether in the Fe-ZSM5/H₂O₂ system revealed that adsorption plays a positive role for the degradation reaction.Comparing the two types of Fe-containing zeolites applied in this study, Fe-Beta showed a lower catalytic activity for H₂O₂ decomposition and also MTBE degradation. However, in terms of utilization of H₂O₂ for MTBE degradation Fe-Beta is advantageous over Fe-ZSM5. This could be explained by the stronger adsorptive enrichment of MTBE on the Fe-Beta zeolite. This study shows that Fe-containing zeolites are promising catalysts for oxidative degradation of MTBE by H₂O₂.     

An experimental study on the application of polymer membranes to the catalytic decomposition of MTBE (methyl tert.-butyl ether)

In this experimental study, the methyl tert.-butyl ether (MTBE) decomposition was carried out in various inert membrane reactors composed of H₃PW₂O₄₀ and a polymer membrane. Polycarbonate (PC), polyarylate (PA) and cellulose acetate (CA) membranes were used in the membrane reactor. It was revealed that all the tested polymer membranes showed larger permeability of methanol than that of either MTBE or isobutene, and the membrane reactor showed better performance than the corresponding fixed bed reactor. The perm-selectivity of methanol/MTBE was in the order of CA > PC > PA, and the permeation ratio of product/MTBE was in the order of CA > PA > PC. Among the membrane reactors tested CA membrane reactor showed the best performance. The enhanced performance of the membrane reactor was mainly due to the selective permeation of methanol that made a methanol-deficient phase suppressing MTBE synthesis reaction in the reversible reaction.     

臭氧-生物活性炭技术处理MTBE污染水体的研究

本文采用臭氧-生物活性炭（O3-BAC）组合工艺处理含MTBE的污染水体，研究了影响处理效果的各种因素，提出优化的工艺及运行参数，并讨论了MTBE的去除机理。研究表明：臭氧／过氧化氢氧化一混凝沉淀一生物活性炭组合工艺能有效处理受MTBE污染的河道水。在MTBE浓度为10mg／L时，COD的去除率为80％，MTBE的去除率达到92．8％。采用GC／FID检测MTBE及其氧化产物，通过GC保留时间的比较确定臭氧氧化MTBE的中间产物为叔丁醇（TBA），叔丁基甲酯（TBF）、丙酮等。     

HF/USY分子筛催化合成2-叔丁基对甲酚

以USY负载 HF为催化剂、甲基叔丁基醚（MTBE）和对甲酚为原料,在小型固定床反应器上进行合成2-叔丁基对甲酚的研究,考察了HF负载量、反应温度、空速及原料配比对反应转化率和选择性的影响以及催化剂的稳定性。结果表明,HF改性后,USY的L酸中心增加,B酸中心减少,对甲酚转化率增大。L酸中心是烷基化反应的主要活性中心。最佳反应条件为：反应温度160 ℃,HF负载质量分数1%,空速1.2 h^-1,n(MTBE):n(对甲酚)＝1.5∶1。最佳条件下,对甲酚的转化率84.4%,2-叔丁基对甲酚的选择性98.6%。催化剂使用110 h,仍保持较好的催化活性。     

Synthesis of MTBE in zeolite membrane reactors

A zeolite membrane was employed to selectively remove water from the reaction atmosphere during the gas-phase synthesis of methyl-tert-butyl ether (MTBE) from tert-butanol and methanol. This reaction was carried out over a bed of Amberlyst™ 15 catalyst packed on the inside of a zeolite tubular membrane. The results obtained with different hydrophilic membranes (mordenite or NaA zeolite) are presented. Prior to reaction, the zeolite membranes were characterized by measuring their performance in the separation of the equilibrium mixture containing water, methanol, tert-butanol, MTBE and isobutene. The results obtained with zeolite membrane reactors (ZMR) were compared with those of a fixed bed reactor (FBR) under the same operating conditions. MTBE yields obtained with the ZMR at 334 K reached 67.6%, under conditions where the equilibrium value without product removal (FBR) would be 60.9%.     

Oxidation of Methyl tert-Butyl Ether (MTBE) and Ethyl tert-Butyl Ether (ETBE) by Ozone and Combined Ozone/Hydrogen Peroxide

The aim of this work was to study the reaction of ozone and combined ozone/hydrogen peroxide on oxygenated additives such as methyl tert-butyl ether (MTBE) and ethyl tert-butyl ether (ETBE) in dilute aqueous solution using controlled experimental conditions. Experiments conducted in a semi-continuous reactor with MTBE and ETBE in combination (initial concentration: 2 mmol/L of each) showed that ETBE was better eliminated than MTBE with both ozone and combined O₃/H₂O₂. Batch experiments led to the determination of the ratio of the kinetic constants for the reaction of OH°-radical with MTBE and ETBE [k_OH°/ETBE/k_OH°/MTBE = 1.7). Tert-butyl formate and tert-butyl acetate were identified as the ozonation byproducts of MTBE and ETBE, respectively, while tert-butyl alcohol was found to be produced during the ozonation of both compounds.     

Fenton-driven regeneration of MTBE-spent granular activated carbon—Effects of particle size and iron amendment procedures

Fenton-driven regeneration of spent granular activated carbon (GAC) can be used to regenerate organic contaminant-spent GAC. In this study, the effects of GAC particle size (>2 mm to <0.35 mm) and acid pre-treatment of GAC on Fenton-driven oxidation of methyl-tert-butyl ether (MTBE)-spent GAC were evaluated. Iron (Fe) was amended to the GAC using two methods: (1) untreated—where GAC was amended with a concentrated solution of ferrous sulfate and (2) acid pre-treatment—where GAC was amended with acid followed by sequential applications of a dilute ferrous sulfate solution. Subsequently, MTBE was amended to the GAC, followed by oxidative treatments with H₂O₂. H₂O₂ reaction and MTBE oxidation were inversely correlated with GAC particle size and were attributed to shorter intraparticle diffusion transport distances for both H₂O₂ and MTBE. Image analysis of the GAC cross-sections (i.e., prepared thin sections) revealed that the Fe amended to the GAC extended to the center of the GAC particles. Fe accumulated at higher levels on the periphery of the untreated GAC but Fe dispersal was more uniform in the acid pre-treated GAC. In the acid pre-treated GAC, conditions for MTBE oxidation were favorable and greater levels of MTBE oxidation were measured for all particle size fractions tested. Modeling and critical analysis of H₂O₂ diffusive transport and reaction indicated limited H₂O₂ penetration into large GAC particles which contributed to a decline in MTBE removal. Residual MTBE remaining on the GAC limited the quantity of MTBE that could be re-adsorbed, but no reduction in MTBE sorption capacity resulted from oxidative treatments.     

MTBE装置工艺中危险因素分布初探

MTBE装置从加工原料到产品均为易燃易爆并易挥发物质,一旦泄漏其蒸气就可能与空气混合形成爆炸性气体混合物,且发生的醚化反应为中强度放热反应,因此本装置存在的主要危险因素为火灾爆炸。对比MTBE装置中的催化蒸馏塔、甲醇萃取塔和甲醇回收塔装置的危险因素,找出MTBE装置的危险隐患分布。     

用工业品甲基叔丁基醚合成TBHQ的研究

研究了以工业品甲基叔丁基醚（MTBE）和对苯二酚（HQ）为原料,在硫酸催化下,合成食品抗氧剂TBHQ的工艺参数。对催化剂的活性、原料的配比和反应时间等进行了优化考察。当对苯二酚∶甲基叔丁基醚∶硫酸=1∶1∶0.5（mol）,反应温度为115℃,反应时间3 h,TBHQ的收率达77.65%。与传统方法相比,该方法具有价廉、操作简单的特点,具有较高的开发、应用价值。     

UV/O3工艺去除甲基叔丁基醚过程中BrO3-的产生与控制

引言臭氧用于饮用水处理已有悠久的历史,可有效去除色度和浊度,除异味,降解有机污染物和提高可生物降解性能。由于臭氧在紫外的激发下产生氧化能力更强的羟基自由基(·OH),该氧化剂与许多物质的反应速率常数在108～1010之间,因此,臭氧与紫外的联合作用能够迅速降解多种持久性有机物。面对水源地中出现的种类繁多的持久性有机物,UV/O3工艺受到了越来越多的关注。