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研究了浆态床中自行开发的LP201甲醇合成催化剂上二氧化碳加氢合成甲醇的过程。探讨了不同操作条件,如温度、压力、气体空速、原料气配比等对反应的影响;考察了该催化剂在浆态床二氧化碳加氢合成甲醇过程中的稳定性。实验结果表明,浆态床二氧化碳加氢合成甲醇过程中主要产物为甲醇、CO和水;随温度的增加,CO2的转化率和甲醇产率呈现上升的趋势,但甲醇的选择性明显下降;压力的升高有利于CO2的转化率、甲醇产率以及甲醇的选择性提高;原料气空速的提高会增大甲醇产率,但同时降低CO2的转化率以及甲醇的选择性;CO2的转化率、甲醇收率以及甲醇的选择性在氢碳摩尔比4~5获得极大值。LP201催化剂的寿命考察结果表明,该催化剂具有较好的催化活性和稳定性。 相似文献
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完全液相法催化剂上甲醇脱水合成二甲醚的动力学及DFT研究 总被引:1,自引:1,他引:0
采用完全液相法制备AlOOH催化剂并进行了浆态床反应器中甲醇脱水制备二甲醚的反应动力学和DFT的研究。在3种甲醇脱水制备二甲醚的反应机理中,以表面反应即两个同时吸附的甲醇反应生成二甲醚作为速控步骤,所建立动力学模型的计算值和实验值吻合较好。采用DFT计算了液体石蜡环境中AlOOH(100)面的脱水反应,其反应过程和活化能结果与动力学模型结果基本一致,进一步表明采用该模型可以合理描述完全液相法制备的AlOOH催化剂表面甲醇脱水反应过程。 相似文献
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浆态F—T法宏观反应动力学的参数估计 总被引:2,自引:1,他引:1
利用浆态床 F-T 合成反应,经长周期试验数据估算宏观反应动力学参数。用多组分数学模型,考虑了反应器内催化剂浓度间歇变化,并引入催化剂活性修正因子,采用正交排列与单纯形方法进行计算。最后用得到的动力学参数进行模拟计算,合成气转化率预报值与实测值相对误差2.5%,最大误差7.7%。可以认为采用的数学模型及动力学参数可以描述用沉淀铁催化剂,进行浆态床 F-T 合成反应的结果。 相似文献
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利用磷酸浸渍改性甲醇脱水催化剂γ-Al2O3得到的P-γ-Al2O3与甲醇合成催化剂C301制备双功能催化剂(C301/P-γ-Al2O3).以C301/P-γ-Al2O3为催化剂,液体石蜡为溶剂,在浆态床反应器中研究合成气一步法制二甲醚(DME),考察了反应温度、压力、空速和合成气中的CO2含量对一步法制DME的影响... 相似文献
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考察了过渡金属钼作为助催化剂添加到完全液相法制备的CuZnAl浆态催化剂中,对催化剂结构和CO加氢液相反应的产品分布的影响。Mo改性CuZnAl催化剂在250℃,5.0 MPa,空速为360 mL/(g·h)和V(H2)/V(CO)=1条件下进行活性评价,在500 mL浆态床中CO加氢反应120 h;并运用XRD,H2-TPR,NH3-TPD和BET对催化剂进行表征。结果表明:完全液相法制备的Mo-CuZnAl催化剂对液相CO加氢反应有良好稳定性;Mo助剂能促进铜氧化物在较低温度还原,增强催化剂表面酸性,在温和条件下提高烃,特别是甲烷的选择性。 相似文献
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采用完全液相法制备了不同SiO2含量的二甲醚(DME)合成CuZnAlSi双功能催化剂,并在浆态床反应器中评价其催化反应活性,通过in-situ XPS、XRD、BET、NH3-TPD等方法对其物理化学性能进行研究。结果表明,CuZnAl催化剂中加入SiO2组分,能够促进活性组分Cu的分散,并通过与AlOOH的作用调变催化剂的孔结构和表面酸性,从而提高催化剂在DME合成反应中的活性。准原位 XPS表征结果显示,还原后的催化剂表面Cu0和ZnO共同构成DME合成反应中的甲醇合成活性中心。SiO2的加入可能导致Cu、Zn和Al组分间的相互作用减弱,催化剂稳定性降低。 相似文献
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在减少CO2释放战役中一个大问题是如何处理来自工业设备中的所有CO2。日本Kansai电力有限公司联合Mitsubishi重工业公司开发出一种直接用CO2和氢气生产二甲醚(DME)的方法。上述气体经反应可产生甲醇,然后甲醇脱水可生产DME。反应如下:CO2+3H2=CH3OH+H2O2CH3OH=CH3OCH3+H2O两步反应同时在250~300℃和4~10MPa压力下的固定床反应器中进行,使用专用的甲醇合成催化剂和脱水催化剂。附产水从DME-甲醇混合物中分离出来,然后通过蒸馏从过量甲醇中回收DME。在扩大试验中,KEP取得了CO2转换… 相似文献
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Komal Tripathi Vrinda Gupta Varsha Awasthi Kamal Kishore Pant Sreedevi Upadhyayula 《加拿大化工杂志》2023,101(6):3213-3225
A comprehensive thermodynamic study was conducted to evaluate the comparative efficacy of methanol and dimethyl ether (DME) synthesis using CO2 rich syngas feed. The first part of our study included assessing the relative performances of the methanol synthesis system, two step DME synthesis system, and one step DME synthesis system in terms of the COx conversion and product yield (methanol/DME) based on the Gibbs free energy minimization approach. The wide range of composition of CO2-enriched syngas feed produced by the coal and biomass gasification was simulated using Aspen Plus and the following evaluation parameters were analyzed for a broad parameter range: reaction temperature (180–280°C), reaction pressure (10–80 bar), stoichiometry number (SN) (0–11), and CO2/(CO2 + CO) molar feed ratio (0–1) for isothermal as well as adiabatic conditions. Based on the equilibrium yield, one-step DME synthesis was discovered as the most viable process to utilize the co-gasification derived syngas effectively. In the second part of our study, the overall process efficiency was inspected through the process design of 1 tonnes per day (TPD) DME plant inclusive of heat integration, resulting in significant CO2 abatement and DME production with high product purity and minimum energy consumption. Consequently, one-step DME production via CO2-enriched syngas obtained through the coal or biomass gasification process is identified as the leading technology based on energy utilization and CO2 abatement. 相似文献
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Gokhan Celik Ayca Arinan Aysegul Bayat H. Onder Ozbelge Timur Dogu Dilek Varisli 《Topics in Catalysis》2013,56(18-20):1764-1774
Dimethyl ether (DME), which is an excellent green diesel fuel alternate, is synthesized following a direct synthesis route from synthesis gas, by using a bi-functional catalyst mixture, which was composed of a silicotungstic acid incorporated mesoporous catalyst [TRC-75(L)] and a commercial Cu–Zn based catalyst. Higher DME selectivity values were obtained by using TRC-75(L), than commercial γ-alumina at 50 bars. Presence of CO2 in the feed stream caused significant enhancement in DME selectivity. Results showed that DME selectivity of about 0.85 was obtained in a temperature range 250–275 °C in the presence of 10 % CO2. In fact, CO2 was also used as a resource to produce DME at lower temperatures. Reverse dry reforming and ethanol formation reactions were observed as side reactions, especially at higher temperatures. Results also proved that direct synthesis of DME from syngas has major CO conversion and DME selectivity advantages over the two step process involving consecutive methanol synthesis and dehydration steps. 相似文献
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I. I. Lishchiner O. V. Malova A. L. Tarasov S. V. Korobtsev M. F. Krotov B. V. Potapkin 《Catalysis in Industry》2016,8(3):205-212
Dimethyl ether (DME) synthesis from syngas over a mixture of a methanol synthesis catalyst (ZnO, 25.10 wt %; AuO, 64.86 wt %; Al2O3, 10.04 wt %) and a methanol dehydration catalyst (γ-A12O3) has been investigated for one-, two-, and three-layer catalyst beds. There is a common regularity for these three variants: with an increasing temperature, the total CO conversion decreases, the CO-to-methanol conversion decreases, and the CO-to-DME conversion increases. The largest values of DME selectivity and DME yield have been attained with the three-layer bed. The highest DME yield has been obtained at 250–285°C. Use of a mechanical mixture of the methanol synthesis catalyst and alumina makes it possible to efficiently obtain DME from syngas ballasted with nitrogen (20 vol %) at an H2/CO ratio of 1, which is unfavorable for methanol synthesis. The DME yield on the syngas input basis in this case with the ballast gas (nitrogen or CO2) taken into account can be about 10 wt %. 相似文献
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The low-temperature catalytic dehydration of methanol to dimethyl ether (DME) has been analyzed. Efficient sulfocationic catalysts for the liquid-phase dehydration of methanol within a temperature range of 90–150°C and polyoxide catalysts for the gas-phase dehydration of methanol within a temperature range of 130–220°C have been selected. Kinetic models of these reactions are constructed, and their constants are determined from the results of kinetic experiments. The constructed models are shown to be adequate to experiment. The selected catalysts open additional opportunities for intensifying the processes of DME synthesis from methanol and syngas, abruptly reducing the primecost of the target product, dimethyl ether. 相似文献
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Prasert Reubroycharoen Suwattana Teppood Tharapong Vitidsant Chaiyan Chaiya Suchada Butnark Noritatsu Tsubaki 《Topics in Catalysis》2009,52(8):1079-1084
A new DME synthesis route from syngas at a relatively low temperature (443 K) has been developed for the first time by the
combination of a conventional DME synthesis catalyst (Cu/ZnO:HZSM-5 catalyst) with methanol as a catalytic solvent. The addition
of methanol to the reaction system is the key to the success of DME synthesis at this temperature. Indeed, a CO conversion
of 29 and 43% with a DME selectivity of 69 and 68% were achieved at 443 or 453 K, respectively, and 4 MPa, when methanol was
used as a catalytic solvent. Importantly, no other by-products including methanol and hydrocarbons were observed in the DME
product attained, suggesting no significant subsequent purification stages. Assuming no scale up problems, this process potentially
provides a high purity of DME with less energy consumption, and so offers an opportunity for the economically viable future
sustainable production of DME. 相似文献
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Kai Cai Ying Li Hongbao Shen Zaizhe Cheng Shouying Huang Yue Wang Xinbin Ma 《Frontiers of Chemical Science and Engineering》2021,15(2):319-329
Dimethyl ether(DME)carbonylation is considered as a key step for a promising route to produce ethanol from syngas.Heteropolyacids(HPAs)are proved to be efficient catalysts for DME carbonylation.In this work,the reaction mechanism of DME carbonylation was studied theoretically by using density functional theory calculations on two typical HPA models(HPW,HSiW).The whole process consists of three stages:DME dissociative adsorption,insertion of CO into methoxyl group and formation of product methyl acetate.The activation barriers of all possible elementary steps,especially two possible paths for CO insertion were calculated to obtain the most favorable reaction mechanism and rate-limiting step.Furthermore,the effect of the acid strength of Br?nsted acid sites on reactivity was studied by comparing the activation barriers over HPW and HSiW with different acid strength,which was determined by calculating the deprotonation energy,Mulliken population analyses and adsorption energies of pyridine. 相似文献
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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. 相似文献
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Four CuZnAl slurry catalysts with different contents of Al were directly prepared from the solution of these metal salts to catalyst slurry by a complete liquid-phase method. The structure properties of the catalysts were characterized by XRD, BET, XPS, FTIR, and their catalytic performances for the single-step synthesis of Dimethyl ether (DME) from syngas were evaluated in a slurry reactor of 250 mL with a mechanical magnetic agitator. The results indicate the main phase existed in the catalysts are Cu, Cu2O, ZnO and boehmite (AlOOH) and the structures of pore and surface are comparable with those of the commercial methanol synthesis catalysts. Activity tests show that the slurry catalysts are quite effective for the single-step synthesis of DME from syngas. Among them, the catalyst with 2.09 mol% Al is best, whose DME selectivity reaches 93.08%. All of the catalysts prepared by the novel method exhibit good stability during the reaction time investigated for 18 days. 相似文献