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对煤制合成天然气、一步法合成二甲醚、两步法合成二甲醚3种典型煤化工工艺的进行了比较和能量转化率分析,提出一步法合成二甲醚无论在工艺、投资还是在能量转化率上都较其他2种工艺具有优势。 相似文献
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简述了重要的化工原料——二甲醚的性质、合成方法以及各方法的工艺特点,综述了二甲醚在燃料、气雾剂制冷剂和合成低碳和合成低碳烯烃等方面的应用,指出了二甲醚具有广阔的发展前景。 相似文献
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介绍了氧烃化、乙烯加成、氢解、氯化物分子间的消除、甲醚的偶联等反应,综述了生产与合成乙二醇二甲醚的方法,包括其工艺流程、催化剂和反应条件,并重点介绍了Williamson合成法以及由环氧化合物开环与二甲醚的插入反应合成乙二醇二甲醚的合成工艺路线的研究进展,认为由碳酸二甲酯与乙二醇单甲醚以及甲醚与环氧乙烷制备乙二醇二甲醚,具有重大应用前景。 相似文献
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二甲醚合成工艺技术现状 总被引:3,自引:0,他引:3
简要介绍二甲醚的性质和用途,并对几种主要的二甲醚生产合成技术作了比较,重点介绍了一步法合成二甲醚的工艺,特别介绍了煤制二甲醚的国内外现状及发展趋势,同时还介绍了合成氨联产二甲醚的工艺,并简要分析及预测了二甲醚的市场前景和发展方向。 相似文献
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浆态床中合成二甲醚的研究 总被引:1,自引:0,他引:1
考察了浆态床中3种甲醇合成催化剂反应行为,考察了温度、压力、催化剂比例和种类对二甲醚合成的影响.结果表明,低压下甲醇合成催化剂中C30l活性最好,温度降低和压力升高有利于甲醇的合成.二甲醚合成中,不同脱水催化剂反应性能不同.在考察范围内,温度升高,CO转化率变化不大,二甲醚的选择性增加;压力升高,CO转化率和二甲醚选择性都随之升高;两种催化剂(C301Hβ)的质量比为41时,CO转化率和二甲醚选择性最高. 相似文献
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Simulation of DME synthesis from coal syngas by kinetics model 总被引:1,自引:0,他引:1
Hyun Min Shim Seung Jong Lee Young Don Yoo Yong Seung Yun Hyung Taek Kim 《Korean Journal of Chemical Engineering》2009,26(3):641-648
DME (Dimethyl Ether) has emerged as a clean alternative fuel for diesel. There are largely two methods for DME synthesis.
A direct method of DME synthesis has been recently developed that has a more compact process than the indirect method. However,
the direct method of DME synthesis has not yet been optimized at the face of its performance: yield and production rate of
DME. In this study it is developed a simulation model through a kinetics model of the ASPEN plus simulator, performed to detect
operating characteristics of DME direct synthesis. An overall DME synthesis process is referenced by experimental data of
3 ton/day (TPD) coal gasification pilot plant located at IAE in Korea. Supplying condition of DME synthesis model is equivalently
set to 80 N/m3 of syngas which is derived from a coal gasification plant. In the simulation it is assumed that the overall DME synthesis
process proceeds with steadystate, vapor-solid reaction with DME catalyst. The physical properties of reactants are governed
by Soave-Redlich-Kwong (SRK) EOS in this model. A reaction model of DME synthesis is considered that is applied with the LHHW
(Langmuir-Hinshelwood Hougen Watson) equation as an adsorption-desorption model on the surface of the DME catalyst. After
adjusting the kinetics of the DME synthesis reaction among reactants with experimental data, the kinetics of the governing
reactions inner DME reactor are modified and coupled with the entire DME synthesis reaction. For validating simulation results
of the DME synthesis model, the obtained simulation results are compared with experimental results: conversion ratio, DME
yield and DME production rate. Then, a sensitivity analysis is performed by effects of operating variables such as pressure,
temperature of the reactor, void fraction of catalyst and H2/CO ratio of supplied syngas with modified model. According to simulation results, optimum operating conditions of DME reactor
are obtained in the range of 265–275 °C and 60 kg/cm2. And DME production rate has a maximum value in the range of 1–1.5 of H2/CO ratio in the syngas composition. 相似文献
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Yingying Zhu Xiaolan Ge Qian Liu Zhongyang Luo Kefa Cen 《Fuel Processing Technology》2010,91(4):424-429
Dimethyl ether (DME) has received growing attention due to its potential use as a multi-purpose fuel. A new technical route of improved two step synthesis is proposed for DME production, which is composed of methanol synthesis and methanol dehydration in a fixed-bed reactor. The influences of the operating conditions including reaction pressure, temperature, H2/CO mole ratio in the syngas and space velocity on CO conversion, selectivity and yield of DME are investigated. CO conversion and DME yield both increase monotonically with the pressure increase. The optimal reaction temperatures for the synthesis and dehydration of methanol are different. CO conversion increases at first and keeps constant when the H2/CO mole ratio is above 2. DME yield increases obviously and then decreases gradually with the space velocity increase. The optimal conditions are obtained to maximize the CO conversion and DME selectivity. The reaction temperatures of the top and bottom stage are in the range of 270-280 °C and 235-245 °C, respectively. The optimal ratio of H2/CO is above 2, and the space velocity is in the range of 1000-1300 h− 1. 相似文献
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Wen-Jie Shen Ki-Won Jun Ho-Suk Choi Kyu-Wan Lee 《Korean Journal of Chemical Engineering》2000,17(2):210-216
The thermodynamics involved in the catalytic hydrogenation of CO2 have been examined extensively. By assuming that methanol and dimethyl ether (DME) are the main products, two reaction systems
each consisting of two pararell reactions were analyzed and compared in terms of the equilibrium yield and selectivity of
the useful products, methanol and DME. The calculation results demonstrated that the production of DME allows much higher
oxygenate yield and selectivity than that of methanol. 相似文献
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Sung-Hwan Ahn Song-Hyoung Kim Kwang-Bo Jung Hyun-Sik Hahm 《Korean Journal of Chemical Engineering》2008,25(3):466-470
The effect of pressure on the direct synthesis of dimethyl ether (DME) from syngas over metal (Cu, Zn) pillared ilerites and
metal (Cu, Zn) impregnated metal-pillared ilerites was explored. The prepared catalysts were characterized by XRD, BET, ICP-AES,
SEM and FT-IR. The direct DME synthesis reaction was carried out in a differential fixed bed reactor with the prepared catalysts
at various pressures (10, 20, 30 bar), 250°C and H2/CO ratio of 2. The Cu/Zn-pillared ilerite catalyst showed the highest catalytic activity among the prepared catalysts at
20 bar, in which CO conversion was about 62% and DME selectivity was about 89%. CO conversion increased with pressure, and
DME selectivity increased with pressure in the range of 10–20 bar, and above the pressure slightly decreased with pressure.
The optimum pressure for this reaction was 20 bar. 相似文献
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Design and operation of integrated pilot-scale dimethyl ether synthesis system via pyrolysis/gasification of corncob 总被引:1,自引:0,他引:1
The integrated pilot-scale dimethyl ether (DME) synthesis system from corncob was demonstrated for modernizing utilization of biomass residues. The raw bio-syngas was obtained by the pyrolyzer/gasifier at the yield rate of 40-45 Nm3/h. The content of tar in the raw bio-syngas was decreased to less than 20 mg/Nm3 by high temperature gasification of the pyrolysates under O2-rich air. More than 70% CO2 in the raw bio-syngas was removed by pressure-swing adsorption unit (PSA). The bio-syngas (H2/CO ≈ 1) was catalytically converted to DME in the fixed-bed tubular reactor directly over Cu/Zn/Al/HZSM-5 catalysts. CO conversion and space-time yield of DME were in the range of 82.0-73.6% and 124.3-203.8 kg/mcat3/h, respectively, with a similar DME selectivity when gas hourly space velocity (GHSV, volumetric flow rate of syngas at STP divided by the volume of catalyst) increased from 650 h−1 to 1500 h−1 at 260 °C and 4.3 MPa. And the selectivity to methanol and products was less than 0.65% under typical synthesis condition. The thermal energy conversion efficiency was ca. 32.0% and about 16.4% carbon in dried corncob was essentially converted to DME with the production cost of ca. ¥ 3737/ton DME. Cu (1 1 1) was assumed to be the active phase for DME synthesis, confirmed by X-ray diffraction (XRD) characterization. 相似文献
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Miriam StiefelRuaa Ahmad Ulrich ArnoldManfred Döring 《Fuel Processing Technology》2011,92(8):1466-1474
Various dehydration catalysts were studied in the synthesis of dimethyl ether (DME) directly from carbon-monoxide-rich synthesis gas under a series of different reaction conditions. The investigated catalyst systems consisted of combinations of a methanol catalyst (CuO/ZnO system) with catalysts for methanol dehydration based on γ-Al2O3 or zeolites and γ-Al2O3 was identified as the most favorable dehydration catalyst. Various reaction parameters such as temperature, H2/CO ratio and space velocity were studied. The impact of water on Cu/ZnO/Al2O3-γ-Al2O3 catalysts was investigated and no deactivation could be observed at water contents below 10% during running times of several hours. A running time of several days and a water content of 10% led to a significant increase of CO conversion but the water gas shift reaction became dominating and CO2 was the main product. After termination of water feeding significant deactivation of the catalyst system was observed but the system returned to high DME selectivity. Catalyst stability and the influence of CO2 in the gas feed were studied in experiments lasting for about three weeks. The presence of 8% of CO2 caused an approximately 10% lower CO conversion and an about 5% lower DME selectivity compared to the reaction system without CO2. 相似文献
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艾珍 《化学工业与工程技术》2010,31(1):15-18
综述了合成气一步法合成二甲醚反应器的发展近况,着重介绍了固定床、浆态床及组合床的研究进展,并根据国内外的研究对几种反应器进行了工艺比较。 相似文献
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DME synthesis from syngas via methanol has been carried out in a single-stage liquid phase reactor. Cu/ ZnO/Al2O3 and γ-Al2O3 were used together as methanol synthesis catalyst and dehydration catalyst, respectively. The influence of water on the catalytic
system was investigated mainly. Water affected the activity of methanol dehydration catalyst as well as methanol synthesis
catalyst. Thus, removal of water from the reaction system, by adding a dehydrating agent or controlling methanol formation
rate by the reaction parameters, was efficient in maintaining the high catalytic activity and stability.
Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8-10, 2001), dedicated to Prof. H. S. Chun on the occasion of his
retirement from Korea University. 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