Genetic-based multi-objective optimization of alkylation process by a hybrid model of statistical and artificial intelligence approaches

The purpose of this research is to find the optimal operating point in the production process of the cumene. Therefore, the production process was optimized through statistical and genetic algorithm-based methods. The performance of an alkylation reactor was optimized through maximizing the yield of cumene production. Response surface methodology (RSM) with design type of central composite was applied for design of experiment, modelling, and optimizing the process. The analysis of variance (ANOVA) was performed for finding the important operative parameters as well as their effects. The effects of three parameters including temperature, reactor length, and pressure on the alkylation process were investigated. Further, two types of feed-forward neural network were applied to model the alkylation reactor. To develop the neural network model, leave-one-out method was used. The best prediction performance belonged to a fitting network with 2 and 8 neurons in the hidden layer, respectively. This model was used for optimizing the performance of the alkylation reactor. The statistical and artificial intelligence systems were capable of prediction of cumene production yield in different conditions with R² of 0.9098 and 0.9986, respectively. Genetic algorithm-based optimization was performed by the developed neural network model. The maximum accessible value of cumene production yield was 0.7771, which can be achieved when the temperature, length of reactor, and column pressure are 160°C, 2 m, and 4000 kPa, respectively. By finding the optimal operating point in the cumene production process, capital cost, energy consumption, and other operating costs can be significantly reduced.     

用于合成气制高值产物的InZrOx 氧化物制备及性能

以四水合硝酸铟和五水合硝酸锆为原料，通过共沉淀法和水热法制备InZrOx氧化物，并在最佳制备条件下探究煅烧温度对合成氧化物的影响，与SAPO-34分子筛结合为双功能催化剂用于用于合成气催化转化制高值产物。采用XRD、SEM-EDS、HRTEM、XPS和BET对氧化物的织构性质、晶体结构、形貌特征及表面电荷进行表征与测试，并在固定床反应器中系统研究了空速、原料气氢碳比（物质的量）、氧化物与分子筛质量比、反应温度及反应压力对催化效果的影响规律。结果表明，共沉淀法得到的氧化物在各方面表现均优于水热法，最佳煅烧温度为550 ℃。在空速为2000 mL/(gcat·h)、原料气氢碳比（物质的量）为3：1、m(InZrOx)：m(SAPO-34)=1：1、400 ℃、3 MPa的反应条件下，CO转化率为67.58%，高值产物选择性为70.81%[C2-4=选择性为37.74%、液体燃料（C5+）烃类选择性为33.07%]，C2-4=收率可达23.98%，副产物CO2选择性仅为5.99%。     

Transalkylation of diisopropylbenzene with benzene over SAPO‐5 catalyst: a kinetic study

BACKGROUND: The objective of this work was to improve the selective yield of cumene by transalkylating the (diisopropylbenzene) DIPB formed in benzene alkylation with propene and select the optimum process conditions for this transalkylation over SAPO‐5 catalyst. RESULTS: Higher benzene/DIPB mole ratios and higher space velocities were found to give better cumene selectivity. An apparent activation energy value of 130.2 kJ mol^?1 was obtained for the reaction with SAPO‐5 as the catalyst. CONCLUSION: SAPO‐5 shows promise when loaded with a small quantity of platinum (0.005% w/w) in the transalkylation of commercial DIPB (cumene column bottoms) with benzene. The kinetic investigations help in selecting optimum process operating conditions for maximizing the cumene yields in transalkylation of commercial DIPB over SAPO‐5. Copyright © 2008 Society of Chemical Industry     

异丙醇和苯液相烷基化反应制备异丙苯

研究MWW结构的有机硅微孔沸石催化剂在苯和异丙醇液相烷基化反应中的性能,考察反应温度、反应压力和空速等对催化剂催化性能的影响。结果表明,反应温度低于150℃时,催化剂活性和稳定性较差,主要反应为烷基化反应及异丙醇的分子内脱水和分子间脱水反应,反应产物为异丙苯、丙烯和异丙醚。反应温度高于170℃时,催化剂活性和稳定性良好,异丙醇接近完全转化,主要反应为烷基化反应,主要产物为异丙苯和多异丙苯。随着原料空速的增大,异丙醇转化率和异丙苯选择性降低,异丙醚和丙烯选择性增大。反应压力(1.5~2.5)MPa时,反应为液相烷基化过程,反应压力的变化对催化剂催化性能影响较小。     

Fe-MFI zeolite catalyzed C3 alkylation of benzene

Benzene alkylation with isopropanol has been carried out over ZSM-5 and Fe-MFI zeolites. It was observed that Fe-MFI zeolite showed a better selectivity for cumene (isopropylbenzene) andi/(i+n) propylbenzene ratio. This can be attributed to the acidity characteristic of the zeolite. The effects of variation in reaction conditions such as temperature, mole ratio of benzene/isopropanol and WHSV on the activity and selectivity of Fe-MFI are discussed.     

ALKYLATION OF BENZENE USING BATCH AND CONTINUOUS FIXED-BED REACTORS

Alkylation reactions of benzene with propylene using heterogeneous catalysts H⁺-β zeolite, MCM-22, and ZSM-5 were studied for their affinity for cumene production. This work focused on the gas-phase reaction using different crystalline catalysts at several temperatures and amounts of reactants using both batch and continuous fixed-bed reactors. The properties of baseline commercial H⁺-β catalysts versus versions modified with Ga, La, and Pt were studied. Quantitative analysis of product mixture was performed by gas chromatography. For the batch reactor, β-zeolite produced the highest cumene yield and selectivity of 72% and 92%, respectively, at 225°C. At this temperature, a benzene:propylene dilution of 7:1 molar ratio was the optimum. For the continuous system, cumene production is favored at lower space velocities, higher benzene-to-propylene ratio, and temperatures close to 225°C. Ga modification of the H⁺-β zeolite significantly enhanced cumene yield in the continuous fixed-bed reactor at 225°C, from 27% of the unmodified β-zeolite to 36% for the Ga-modified one. The life span of modified β-catalysts was studied in the fixed-bed reactor for the first eight hours of reaction.     

Selective synthesis of 2-methylquinoline over zeolites

The selective vapour-phase synthesis of 2-methylquinoline by alkylation of quinoline with methanol was carried out over HY, HZSM-5(30), CrHY, CeHY, LaHY, LaKHY and CeHZSM-5(30) zeolites in a fixed-bed reactor at atmospheric pressure. The yields of 2-methylquinoline over modified zeolites, especially those of doubly promoted LaKHY, were found to be higher than those of unmodified zeolites. The maximum yield of 2-methylquinoline obtained was 60.6 wt% at 91.5 wt% selectivity over LaKHY zeolite. The active sites responsible for this methylation were found to be more on Lewis acidic sites available over zeolite systems. This revised version was published online in July 2006 with corrections to the Cover Date.     

ALKYLATION OF BENZENE USING BATCH AND CONTINUOUS FIXED-BED REACTORS

Alkylation reactions of benzene with propylene using heterogeneous catalysts H⁺-β zeolite, MCM-22, and ZSM-5 were studied for their affinity for cumene production. This work focused on the gas-phase reaction using different crystalline catalysts at several temperatures and amounts of reactants using both batch and continuous fixed-bed reactors. The properties of baseline commercial H⁺-β catalysts versus versions modified with Ga, La, and Pt were studied. Quantitative analysis of product mixture was performed by gas chromatography. For the batch reactor, β-zeolite produced the highest cumene yield and selectivity of 72% and 92%, respectively, at 225°C. At this temperature, a benzene:propylene dilution of 7:1 molar ratio was the optimum. For the continuous system, cumene production is favored at lower space velocities, higher benzene-to-propylene ratio, and temperatures close to 225°C. Ga modification of the H⁺-β zeolite significantly enhanced cumene yield in the continuous fixed-bed reactor at 225°C, from 27% of the unmodified β-zeolite to 36% for the Ga-modified one. The life span of modified β-catalysts was studied in the fixed-bed reactor for the first eight hours of reaction.     

碱金属改性对SAPO-34分子筛催化性能的影响

通过等体积浸渍法,制备得到碱金属(Li、Na、K、Rb、Cs)改性的SAPO-34催化剂。并在常压连续固定床反应器上评价了各催化剂的甲醇制低碳烯烃(MTO)的性能,同时对催化剂进行了XRD、FT-IR、NH₃-TPD等表征分析。结果表明,碱金属负载量为2%时,除Cs离子改性的催化剂低碳烯烃的选择性和寿命有所降低外,其他碱金属离子改性的SAPO-34催化剂低碳烯烃的选择性和寿命都有了明显的提高,尤其是Li离子改性的催化剂乙烯+丙烯的选择性达77%左右,寿命相对延长了2.5倍;将该催化剂再生3次后乙烯、丙烯的选择性几乎保持不变。     

Alkylation of benzene with propylene catalyzed by FeCl3-Chloropyridine ionic liquid

Alkylation of benzene with propylene was carried out with FeCl₃-chloro-butyl-pyridine (FeCl₃-[bpc]) ionic liquid as catalyst to obtain cumene. Significant improvements in propylene conversion and cumene selectivity under mild reaction conditions were attained by modification of the catalyst with HCl. Under 20°C, 0.1 MPa, reaction time 5 min, mole ratio of benzene to propylene 10:1 and mass ratio of FeCl₃-[bpc] to benzene 1:100, conversion of propylene can increase from 83.60% to 100.00% and selectivity of cumene can increase from 90.86% to 98.47%. If reaction is carried out in following two stages, the result will be very good. At the initial stage of the reaction, alkylation is the main reaction and a higher conversion of propylene is obtained at a lower temperature. At the later stage of the reaction, transalkylation is the main reaction and selectivity to cumene can be increased by appropriately raising the reaction temperature. Translated from Petrochemical Technology, 2006, 35(9): 819–823 [译自: 石油化工]     

VPT法制备MCM-22分子筛催化剂颗粒及其烷基化性能

采用汽相法（VPT）制备了以成型干胶颗粒为基体的MCM-22分子筛催化剂.利用XRD、SEM和BET测试技术对所制备催化剂进行了物相表征、形貌观察和织构分析,并以苯和丙烯烷基化合成异丙苯为模型反应,在液-固固定床反应器上对所制备催化剂的性能进行了评价.结果表明：汽相法制备的MCM-22分子筛催化剂不仅具有较好的结晶度和较高的微孔表面积,而且具有更好的晶体生长取向性和更加致密的结构;在烷基化反应中也具有很好的活性、选择性和稳定性,特别是对目的产物异丙苯的选择性明显高于水热法（HTS）合成的催化剂,在异丙苯合成上具有很好的应用前景.     

悬浮床催化蒸馏新工艺合成异丙苯

以丙烯与苯烷基化合成异丙苯作为模型反应 ,对悬浮床催化蒸馏新工艺进行了初步探索 .结果表明 ,只要选择合适的催化剂 ,新工艺不仅能够稳定运转 ,而且可在常压、低温和低苯烯比的条件下取得高转化率、高选择性的较好反应结果 .     

ZSM-5/SAPO-5催化合成二芳基乙烷

对二甲苯与苯乙烯烷基化反应制二芳基乙烷反应体系进行考察。采用固定床反应器,在ZSM-5/SAPO-5复合分子筛催化剂下,研究了原料配比、反应温度、反应压力和空速对苯乙烯转化率和二芳基乙烷选择性的影响,确定了最佳工艺条件:苯乙烯与二甲苯物质的量比为1∶6,反应温度70℃,反应压力3.0 MPa,空速1.0 h~(-1),此条件下,苯乙烯转化率达100%,二芳基乙烷的选择性达80.48%。     

甲醇甲苯烷基化流化床反应器的数值模拟

利用甲醇甲苯烷基化工艺生产对二甲苯具有良好的应用前景。甲醇甲苯烷基化催化剂较易积炭失活,且反应存在明显热效应。流化床因传热传质性能好、易实现催化剂连续再生,适合用作甲醇甲苯烷基化反应器。本文采用离散颗粒模型,对甲醇甲苯烷基化流化床反应器进行了数值模拟研究,重点考察了进料比、反应压力、分段进料对反应特性的影响。结果表明,当甲苯进料量给定时：降低反应物中甲苯甲醇比可有效提升对二甲苯产率和选择性,但产物中对二甲苯和烯烃摩尔比值较低;提高反应压力可显著提升甲醇和甲苯转化率,但会降低对二甲苯选择性;在低苯醇比基础上采用甲醇分段进料方式不仅可有效提高甲苯利用率,还可灵活调节产物中对二甲苯和烯烃比率;流化床反应器气体返混不利于获得高对二甲苯选择性,且操作条件变化会造成流化床反应器内气固流动改变,导致气固接触效率或反应物局部分压发生改变,这亦将对反应转化特性造成显著影响。这些结果对于流化床反应器优化和放大具有一定的指导意义。     

模板剂用量对SAPO-11分子筛的物理化学性质及催化萘与甲醇烷基化性能的影响

考察了二正丙胺(DPA)模板剂用量对合成的SAPO-11分子筛的物化特性及催化萘与甲醇的烷基化的影响,并通过XRD、SEM、N2 adsorption-desorption、NH3-TPD、FTIR和29SiMAS NMR等手段对合成的样品进行了表征。结果表明:改变模板剂用量不仅可以调节SAPO-11的孔结构,还会改变Si在分子筛骨架上的分布,从而调节SAPO-11的酸性。当n(DPA)/n(Al2O3)=1.5时,样品具有较大的比表面积和孔容,分别为215 m2/g和0.173 cm3/g;样品的Si区面积最小,Si(nAl)(0相似文献   

Oxidative coupling of methane in fluidized- and packed-fluidized-bed reactors

Oxidative coupling of methane to higher hydrocarbons (C₂₊) using NaOH/CaO and pure CaO as catalyst was studied in fluidized- and packed-fluidized-bed reactors at 700°C to 800°C, partial pressures of methane from 0.5 to 0.7 bar and oxygen from 0.05 to 0.25 bar and a total pressure of ca 1 bar; oxygen conversion amounted generally to 50 to 100 %. C₂₊ selectivity depends for both reactors markedly on temperature and oxygen partial pressure. The optimum temperature ranges between 750 and 800°C. Highest selectivities (ca 76 %) were achieved at the lowest oxygen partial pressure (ca 0.06 bar); maximum yields (ca 13.5 %), however, were obtained at an oxygen partial pressure of ca 0.14 bar. The application of the fluidized-bed reactor is more favourable than the packed-fluidized-bed reactor with respect to operability and C₂₊ selectivity.     

超滤膜法CuO-ZnO复合催化剂的制备及催化性能

采用中空纤维超滤（UF）膜反应器制备了CuO-ZnO复合催化剂,考察了复合方式、ZnO含量及催化反应条件等因素对催化剂性能的影响。结果表明：共沉淀法制备的CuO-ZnO催化剂由于形成的铜锌固溶体具有协同催化效应,其性能优于复配法制备的CuO/ZnO催化剂;当ZnO质量分数为25%时,CuO-ZnO催化剂的比表面积达40.47 m2/g,颗粒粒径为19 nm;该催化剂在反应温度为90 ℃、用量为9 g/L条件下催化异丙苯氧化反应时,过氧化氢异丙苯产率可达38.74%,反应选择性达到84.62%,表现出最佳催化效果。     

以M-92分子筛为催化剂生产异丙苯的研究

利用M-92分子筛为催化剂以丙烯和苯为原料进行液相烷基化技术生产异丙苯,烷基化最佳条件:反应温度为125～145℃;反应压力2.4～2.6MPa;n(苯)∶n(丙烯)=(2～4)∶1;丙烯空速为0.5～1.0h-1。该技术与传统AlCl3相比具有工艺简单、丙烯基本可完全转化、异丙苯选择性高、原材料消耗低、节能、及环境友好等优点,具有一定经济效益。     

Liquid‐Phase Alkylation of Benzene with Propylene Catalysed by HY Zeolites

Benzene alkylation with propylene over a Ca modified HY zeolite to obtain cumene has been studied. Time on stream behavior of the catalyst was quite steady without any sign of deactivation and the results were reproducible. The external mass transfer does not influence the cumene reaction. The pore diffusion has a substantial influence on the cumene reaction only in the final region of the reactor, where the olefin concentration is very low. A simple power law kinetic model fits the experimental data significantly better than other models. A general time and space dependent model was developed to analyze the performance of a two‐phase downflow fixed bed reactor used for alkylation of benzene with zeolite catalyst. The model could be instructive in exploratory simulations evaluating the conditions for benzene alkylation in liquid phase.     

反应条件对D803C-Ⅱ01催化剂上甲醇制低碳烯烃的影响

采用小孔SAPO-34分子筛为活性基质,经过改性、喷雾干燥成型及适当温度焙烧后,得到适用于流化床的二甲醚或甲醇高选择性转化为低碳烯烃的催化剂D803C-Ⅱ01。研究反应温度、反应压力和催化剂停留时间对甲醇制低碳烯烃反应的影响以及D803C-Ⅱ01催化剂再生过程及其变化规律。结果表明,乙烯+丙烯选择性约在425℃达到最大值,在反应总压力不大于0.2 MPa、催化剂停留时间为55 min、催化剂与物料接触时间大于0.2 s条件下,均能保证反应转化率接近100%,但反应接触时间从0.6 s增大至3 s,会造成乙烯+丙烯选择性降低3～5个百分点。