合成气一步法制二甲醚催化剂研究进展

简述了二甲醚的物化特性及其应用前景,对现有的几种合成气一步法合成二甲醚的反应机理及动力学模型进行了概述。分别研究了双功能催化剂中的甲醇合成活性组分和甲醇脱水活性组分,CuO/ZnO/Al₂O₃ 作为甲醇合成组分,活性和稳定性较好,甲醇脱水活性组分以γ-Al₂O₃ 、分子筛及其改性后产物较为常用。探讨了双功能催化剂的制备方法及改性方法。     

二甲醚与合成气反应制乙醇的热力学计算与分析

采用Benson基团贡献法估算得到二甲醚（DME）和乙酸甲酯（MA）的标准生成焓和标准生成吉布斯自由能,在298～1000K时计算了DME与合成气制乙醇（DME羰基化反应、MA加氢反应以及二者组成的总反应）过程中的反应焓变、反应熵变、反应吉布斯自由能变和化学反应的平衡常数。在此基础上,分析了反应压力、反应温度和原料比对DME转化率的影响。在413K、1×105Pa、CO∶DME=1条件下考察了不同H2浓度情况下合成乙醇反应中两个反应的协同效应。分析结果表明,在低于493K、3MPa、n(CO)∶n(DME)=1的条件下有利于合成反应的进行,由于两反应的协同效应,使MA加氢反应的平衡转化率有大幅度提高。     

合成气一步法制二甲醚工艺及催化剂研究进展

二甲醚在车用燃料和民用燃料方面具有良好发展前景。合成气一步法制二甲醚工艺分气相法和浆态床法。综述了合成气一步法制取二甲醚的工艺和催化剂的研究进展以及工业化前景。     

Liquid phase methanol and dimethyl ether synthesis from syngas

The Liquid Phase Methanol Synthesis (LPMeOH^TM) process has been investigated in our laboratories since 1982The reaction chemistry of liquid phase methanol synthesis over commercial Cu/ZnO/Al₂O₃ catalysts, established for diverse feed gas conditions including H₂-rich, CO-rich, CO₂-rich, and CO-free environments, is predominantly based on the CO₂ hydrogenation reaction and the forward water-gas shift reactionImportant aspects of the liquid phase methanol synthesis investigated in this in-depth study include global kinetic rate expressions, external mass transfer mechanisms and rates, correlation for the overall gas-to-liquid mass transfer rate coefficient, computation of the multicomponent phase equilibrium and prediction of the ultimate and isolated chemical equilibrium compositions, thermal stability analysis of the liquid phase methanol synthesis reactor, investigation of pore diffusion in the methanol catalyst, and elucidation of catalyst deactivation/regenerationThese studies were conducted in a mechanically agitated slurry reactor as well as in a liquid entrained reactorA novel liquid phase process for co-production of dimethyl ether (DME) and methanol has also been developedThe process is based on dual-catalytic synthesis in a single reactor stage, where the methanol synthesis and water gas shift reactions takes place over Cu/ZnO/Al₂O₃ catalysts and the in-situ methanol dehydration reaction takes place over -Al₂O₃ catalystCo-production of DME and methanol can increase the single-stage reactor productivity by as much as 80%. By varying the mass ratios of methanol synthesis catalyst to methanol dehydration catalyst, it is possible to co-produce DME and methanol in any fixed proportion, from 5% DME to 95% DMEAlso, dual catalysts exhibit higher activity, and more importantly these activities are sustained for a longer catalyst on-stream life by alleviating catalyst deactivation.     

生物质气一步法合成二甲醚双功能催化剂失活研究

概述了生物质气一步法合成二甲醚双功能催化剂的热失活、中毒失活的原因及其解决方案。提出了载体是二甲醚合成催化剂需要突破的重点,将整体式催化剂载体应用二甲醚合成中,不失为一个新的研究方向。     

生物质合成气一步法合成二甲醚的研究

用共沉淀沉积法制备了生物质合成气直接合成二甲醚(DME)的催化剂,考察了固定床中温度、压力、空速等工艺条件对二甲醚合成性能的影响,同时基于Gibbs自由能最小法对合成DIME反应的化学平衡进行模拟计算,并与实际测试结果相比较.结果表明,模拟结果与测试结果吻合较好.     

能源化工与催化固定床一步法制二甲醚催化剂性能

采用固定床反应装置,以共沉淀法制备甲醇催化剂和一步法合成二甲醚催化剂,采用BET、XRD和SEM对催化剂进行表征。在反应压力2.5 MPa、反应温度260 ℃和空速(500~900) h^-1条件下,催化剂催化活性最好,其中,CO转化率≥90%,二甲醚收率≥60%,二甲醚选择性≥65%。     

Equilibrium calculations for direct synthesis of dimethyl ether from syngas

Thermodynamic analysis of single‐step synthesis of dimethyl ether (DME) from syngas over a bi‐functional catalyst (BFC) in a slurry bed reactor has been investigated as a function of temperature (200–240°C), pressure (20–50 bar), and composition feed ratio (H₂/CO: 1–2). The BFC was prepared by physical mixing of CuO/ZnO/Al₂O₃ as a methanol synthesis catalyst and H‐ZSM‐5 as a methanol dehydration catalyst. The three reactions including methanol synthesis from CO and H₂, methanol dehydration to DME and water–gas shift reaction were chosen as the independent reactions. The equilibrium thermodynamic analysis includes a theoretical model predicting the behaviour and a comparison to experimental results. Theoretical model calculations of thermodynamic equilibrium constants of the reactions and equilibrium composition of all components at different reaction temperature, pressure, and H₂/CO ratio in feed are in good accordance with experimental values.     

合成气一步法制二甲醚研究进展

综述了合成气一步法制二甲醚的研究进展,包括气相法、液相法反应条件及催化剂的研究进展。     

合成气一步法制二甲醚过程的热力学模拟研究

使用Aspen plus软件对合成气一步法制二甲醚过程进行热力学模拟计算。考察了温度、压力、合成气组成及CO2体积分数对CO转化率、二甲醚选择性和产率的影响。模拟结果与文献实验结果相比对,具有较好的一致性。     

Dehydration of methanol over Nordstrandite based catalysts for dimethyl ether synthesis

This study focused on the investigation of Nordstrandite as a catalyst for dehydration of methanol to dimethyl ether synthesis. The structure phase of Nordstrandite has been changed to boehmite and γ-Al₂O₃ in sequence via calcinations at various temperatures. Moreover, the properties of the samples have been varied significantly with heat treatment. The number of acid sites of Nordstrandite was much higher than the other aluminas. However, the catalytic activity of Nordstrandite was comparable to the other catalysts with fewer amounts of acid sites. This means that structure phase is one of the most important factors for catalytic performance in this reaction.     

Higher alcohol synthesis from syngas over KCoMoP catalysts

Carbon modified K_xCo_0.75MoP (0 ≤ x ≤ 1.5) catalysts were prepared from a sol–gel method using citric acid as a complexant. The catalysts were evaluated with CO hydrogenation and characterized by XRD, XPS and CO₂-TPD techniques. Results show that the addition of cobalt accelerates the dispersion of catalytic components in phosphide catalysts while the participation of potassium in phosphide catalysts enhances the interaction between MoP and CoMoP and facilitates the rearrangement of electron density in different Mo species. In K₁Co_0.75MoP, a large number of Mo^4 + species resulted in high selectivity to C_2 + higher alcohol.     

合成气合成二甲醚平衡转化率及选择率计算模型

对合成气合成二甲醚反应体系进行热力学参数计算,应用SHBWR状态方程计算了各组分的逸度系数。选取CO、CO2 加氢合成甲醇及甲醇脱水生成二甲醚为独立反应,CO、CO2、二甲醚为关键组分,提出了合成气合成二甲醚的碳转化率、二甲醚与甲醇选择率及收率的计算模型。讨论了温度、压力、原料气组成对合成气合成二甲醚化学平衡的影响。     

串联催化剂在二甲醚与合成气制备乙醇反应中的性能研究

通过水热合成法和共沉淀法分别制备了分子筛催化剂和Cu/ZnO催化剂,将分子筛与Cu/ZnO调控成双层串联催化剂,并用于二甲醚与合成气通过两段反应制备乙醇。研究了反应温度和反应气组成等因素对反应的影响,比较了分子筛类型、助剂种类和含量等对催化剂活性的影响。结果表明,随反应温度增加,DME转化率和乙醇选择性呈现先增加后减小趋势,随着DME含量减少和CO含量增加,DME转化率和乙醇选择性增加。H-MOR分子筛与Cu/ZnO串联催化剂显示了最佳的催化活性;金属助剂能提高催化剂活性,尤其是含5%Cu的Cu/H-MOR与Cu/ZnO串联催化剂显示了最佳的催化反应活性,于最佳反应温度493 K下以Ar/DME/CO/H_2(1.6/1.0/47.4/50.0)为原料进行反应,DME转化率达到33.6%,乙醇选择性达到了44.5%。     

合成气一步法制备二甲醚的工艺流程模拟与优化

二甲醚作为燃料的替代品,其生产开发在化学工程领域受到了广泛关注。本文对合成气一步法制备二甲醚过程进行了模拟分析,提出了用水作为吸收剂并采用多效精馏的二甲醚生产新工艺。利用Aspen Plus化工模拟软件对吸收塔进行模拟比较了甲醇和水作为吸收剂的能耗,模拟结果表明,用水吸收较甲醇吸收总热负荷降低23.54％,总冷负荷降低35.97％,更为节能。从节能降耗角度出发,根据不同的分离任务,提出了采用两塔分离甲醇-水及三塔分离甲醇-水的两项工艺改进措施。结果表明,采用两塔分离甲醇-水工艺比原工艺二甲醚产量增加了11.50%,能量消耗无明显变化。进一步采用三塔精馏工艺总冷负荷比原工艺减少45.07％,总热负荷减少19.27%,且二甲醚产量增加11.15％,节能效果显著。     

三相床中合成气一步法制二甲醚

在反应温度 2 30～ 2 70℃、压力 2～ 5MPa下 ,以医药用石蜡油为惰性液相介质 ,使用C30 2铜基催化剂和CM - 3- 1改性分子筛组成的复合催化剂 ,在三相搅拌釜中研究了合成气 (CO、CO2 、H2 )一步法合成二甲醚的反应。结果表明随着温度的升高 ,碳的转化率增加 ,二甲醚的选择性提高 ,甲醇的选择性降低 ;随着压力的增加 ,碳的转化率升高 ,二甲醚的选择性提高 ,甲醇的选择性降低     

浆态床合成气合成二甲醚的工艺研究

考察了反应温度、反应压力、进料空速对浆态床合成二甲醚反应过程的影响,结果表明,在245～300℃范围内,随着反应温度的升高,一氧化碳转化率、二甲醚选择性和时空收率逐渐增加,在265℃时达到最大值后开始下降;在3.0～5.0MPa范围内,随压力的升高,一氧化碳转化率、二甲醚选择性和时空收率逐渐增加;在700～2500h-1范围内,一氧化碳转化率、二甲醚选择性随空速的增加而逐渐减小,空速以1200h-1为宜。     

复合固体酸催化剂在合成气制二甲醚中的应用研究

对镁碱沸石(FER)进行Zn、Mn金属改性,对γ-Al2O3进行S2O2-3、Ni2+改性,将改性后的FER和γ-Al2O3复合用于合成气直接制二甲醚催化剂中,作为甲醇脱水催化剂组分,制备出了Cu-Zn-Al/ASN/FZM双功能催化剂.在连续固定床高压反应器中,研究了改性条件、复合比及反应温度对催化剂性能的影响.在2...     

生物质合成气合成二甲醚的研究

在加压固定床反应装置上进行了生物质合成气合成二甲醚(DME)的研究.采用机械混合法制备二甲醚合成双功能催化剂.考察了组成为V(H_2):V(CO):V(CO_2):V(CH_4)=52:24:23:1的生物质合成气在不同反应温度、空速、压力下对合成二甲醚反应的影响.同时进行了102 h的催化剂的稳定性实验.结果表明,在260-300℃范围内,随反应温度的升高,CO转化率和二甲醚的选择性均先增大后减小;随反应压力的升高,CO转化率和二甲醚选择性都随之升高;原料气中高浓度的CO_2可导致铜基催化剂较快的失活.     

合成气经二甲醚/乙酸甲酯制无水乙醇的研究进展

乙醇是一种重要的清洁能源,可以作为燃油替代品或者含氧添加剂使用,市场潜力巨大。由合成气出发,经二甲醚羰基化合成乙酸甲酯、乙酸甲酯加氢制乙醇是近年来备受关注的乙醇合成新工艺。该工艺选择性高、反应条件温和、催化剂价廉易得,且避免了乙醇-水共沸物的产生,节省了分离的能耗,是典型的绿色化学工艺。围绕这一工艺的两步核心反应(羰基化和加氢)的研究现状进行了综述,着重介绍了催化剂开发、反应机理方面的进展。该工艺路线的研究和推广,对促进我国能源多元化、清洁化发展有重要的意义。