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《应用化工》2022,(9):1947-1951
为了探究线筒式直流电晕等离子重整CH_4和CO_2制合成气的效果,利用直流电晕放电装置对CH_4和CO_2进行了重整实验。考察了大气压下甲烷含量、放电电压和进气流量对反应物转化率、产物选择性和能量转化效率的影响。结果表明,随着进气中甲烷含量的增大,CH_4转化率下降,CO_2转化率上升,产物选择性和能量转化效率皆先上升后下降;随着电压的增大,原料转化率和选择性皆呈上升趋势,但都存在一个极限值,能量转化效率先上升后下降;随着进气流量的增大,原料转化率和产物选择性皆下降,能量转化效率先上升后下降。整体上,线筒式直流电晕等离子体重整甲烷和二氧化碳制取合成气具有设备简单、产物选择性高和能量转化效率高的优点。 相似文献
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甲烷二氧化碳氧气氧化重整的研究 总被引:3,自引:0,他引:3
在镍基催化剂化的甲烷二氧化碳重整反应中加入氧气使得热性的甲烷选择性氧化与吸热的二氧化碳重整责任中反应能够同时进行。实验结果表明,氧气的加入降低了反应温度,同时还可以在一定程度上调节H2CO比。良好的催化剂稳定性可能是由于镍粒子在表面镧氧化物中的分布的结果。 相似文献
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综述了90年代以来CH4-CO2重整反应在改性镍基催化剂、贵金属负载型催化剂和分子筛催化材料研究方面的最新发展。 相似文献
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由于二氧化碳重整甲烷制合成气具有很多优点,因此引起了广泛的关注。本文综述了二氧化碳重整甲烷制取合成气的研究进展,介绍了二氧化碳重整甲烷热力学、甲烷和二氧化碳的活化、二氧化碳重整甲烷反应过程中的表面积碳和消碳和二氧化碳重整甲烷反应机理的研究现状,并进行了讨论和分析。 相似文献
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The kinetics of CO2 reforming of methane has been studied at 976-1033K on a commercial NiO/CaO/Al2O3 catalyst in a packed-bed continuous reactor. The reaction was carried out at atmospheric pressure and CO2/CH4 ratio > 2. The Hougen-Watson rate models were fitted to experimental data assuming the dissociative adsorption of methane as the rate-determining step. The reaction rate showed an effective reaction order of about unity for CH4. The apparent activity energy was found to be 104kJ·mol-1. Therefore the kinetic reaction parameters were determined and a possible reaction mechanism was proposed. 相似文献
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Richard Blom Ivar M. Dahl se Slagtem Bjrn Sortland Aud Spjelkavik Elisabeth Tangstad 《Catalysis Today》1994,21(2-3):535-543
Nickel on lanthanum-modified aluminas were prepared and tested as catalysts for the CO2 + CH4 2CO + 2H2 reaction in a fluidized-bed reactor. Attrition tests show that lanthanum increases the strength of the carrier significantly. TPR and XRD results indicate that nickel enters into positions in the Al-O spinel blocks of the subsurface LaAl12O19 phase. This results in lower reducibility and thus lower activity for the reforming reaction as compared to nickel on unmodified alumina. While the unmodified catalyst deactivated rapidly under the chosen test conditions, the modified catalysts seem to be stable over several hours. However, the stability is sensitive to the pretreatment conditions of the catalysts. 相似文献
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Eakkapon Promaros Suttichai Assabumrungrat Navadol Laosiripojana Piyasan Praserthdam Tomohiko Tagawa Shigeo Goto 《Korean Journal of Chemical Engineering》2007,24(1):44-50
The carbon dioxide reforming of methane under periodic operation over a commercial Ni/SiO2·MgO catalyst was investigated at two different temperatures, 923 and 1,023 K. According to this operation, pure methane and
carbon dioxide were alternately fed to the catalyst bed where methane cracking and the reverse Boudouard reaction took place,
respectively. Therefore, hydrogen and carbon monoxide products appeared separately in different product streams. The performance
of this operation was compared to that of the steady state operation with simultaneous feed of both carbon dioxide and methane.
At 1,023 K, the methane conversion and hydrogen yield from the periodic operation initially decreased with time on stream
and eventually leveled off at values about half of those obtained in the steady state operation with co-feed of both reactants.
The decreased catalytic activity was due to the accumulation of carbonaceous deposit and loss of metal active sites. However,
a different trend was observed at 923 K. The methane conversion and hydrogen yield were almost constant over the time on stream,
although more carbonaceous deposit was progressively accumulated on the catalyst bed during the reaction course. At this temperature,
the periodic operation offered the equivalent hydrogen yield to the steady state operation. The observed behavior could be
due to the different mechanisms of carbon formation over the catalyst. Finally, it was found that cycle period and cycle split
did not influence the reaction performance within the ranges of this study. 相似文献
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采用XRD、氢化学吸附作用、TPR和XPS等技术研究了共沉淀方法制备N i-Ce-ZrO2催化剂对二氧化碳甲烷重整的性能。N i的载入量和CeO2与ZrO2的比率系统地被改变将使N i-Ce-ZrO2催化剂最优化。发现15w t%N i与Ce0.8Zr0.2O2共沉淀有体相的状态,在800℃用CH4制合成气超过97%,并且经过100h的反应,活性被维持没有重大的损失。 相似文献
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Xiao‐Song Li Bin Zhu Chuan Shi Yong Xu Ai‐Min Zhu 《American Institute of Chemical Engineers》2011,57(10):2854-2860
The spark‐discharge plasma, generated between tubular and rotary‐disc electrodes using a sine‐wave high voltage with 5 kHz frequency, was explored for CO2 reforming of CH4. Based upon the investigation on the effects of specific energy input and CO2/CH4 ratio, the energy costs (EC) and fuel‐production efficiencies (η) at various CO2/CH4 ratios (r) in the same conversion range were compared and accordingly their sequences were given: EC (r = 0.5) and EC (r = 3) are the lowest; η(r = 0.5) is the highest. Compared with other nonthermal discharge techniques, the kilohertz spark discharge exhibits low EC and high fuel‐production efficiency, especially at high total‐carbon conversions. Preliminary investigation on partial oxidation and CO2 mixed reforming at (O2 + CO2)/CH4 = 0.5 exhibited high H2/CO ratio (nearly 2) and low total‐carbon EC (0.59–0.96 MJ/mol, 58–77% of total‐carbon conversion, and O2/(CO2 + O2) = 0.8). © 2010 American Institute of Chemical Engineers AIChE J, 2011 相似文献
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Soon Sam Kim Masih Jorat Gerald Voecks Andras Kuthi Subbarao Surampudi Ronald L. Kent 《American Institute of Chemical Engineers》2020,66(4):e16880
A scaled-up dielectric barrier discharge (DBD) reactor has been developed and demonstrated for the production of hydrogen from steam methane reforming (SMR) by catalytic nonthermal plasma (CNTP) technology. Compared to SMR, CNTP offers conversion at ambient pressure (101.325 kPa), low temperature with better efficiency, making it suitable for distributed hydrogen production with small footprint. There have been several lab-scale DBD reactors reported in the literature. Dimension of the scaled-up DBD reactor is about six times the lab-scale version and can produce 0.9 kg H2/day. The scale-up is, however, nonlinear; several technical innovations were required including spray nozzle for homogeneous introduction of steam, perforated tube central electrodes for generation of homogeneous plasma. Conversion efficiency of the scaled-up DBD reactor is 70–80% at 550°C and 500 W. A continuous run of 8 hr was demonstrated with typical product gas composition of 69% H2, 6% CO2, 15% CO, 10% CH4. 相似文献
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Carbon dioxide reforming of methane to syngas is one of the primary technologies of the new poly-generation energy system
on the basis of gasification gas and coke oven gas. A free energy minimization is applied to study the influence of operating
parameters (temperature, pressure and methane-to-carbon dioxide ratio) on methane conversion, products distribution, and energy
coupling between methane oxidation and carbon dioxide reforming methane. The results show that the methane conversion increases
with temperature and decreases with pressure. When the methane-to-carbon dioxide ratio increases, the methane conversion drops
but the H2/CO ratio increases. By the introduction of oxygen, an energy balance in the process of the carbon dioxide reforming methane
and oxidation can be realized, and the CO/H2 ratio can be adjusted as well without water-gas shift reaction for Fischer-Tropsch or methanol synthesis.
This work was presented at the 6
th
Korea-China Workshop on Clean Energy Technology held at Busan, Korea, July 4–7, 2006. 相似文献
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High‐temperature CO2 selective membranes offer potential for use to separate flue gas and produce a warm, pure CO2 stream as a chemical feedstock. The coupling of separation of CO2 by a ceramic–carbonate dual‐phase membrane with dry reforming of CH4 to produce syngas is reported. CO2 permeation and the dry reforming reaction performance of the membrane reactor were experimentally studied with a CO2–N2 mixture as the feed and CH4 as the sweep gas passing through either an empty permeation chamber or one that was packed with a solid catalyst. CO2 permeation flux through the membrane matches the rate of dry reforming of methane using a 10% Ni/γ‐alumina catalyst at temperatures above 750°C. At 850°C under the reaction conditions, the membrane reactor gives a CO2 permeation flux of 0.17 mL min?1 cm?2, hydrogen production rate of 0.3 mL min?1 cm?2 with a H2 to CO formation ratio of about 1, and conversion of CO2 and CH4, respectively, of 88.5 and 8.1%. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2207–2218, 2013 相似文献
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《Chemical engineering journal (Lausanne, Switzerland : 1996)》2003,91(1):23-31
This work is dedicated to the study of methane steam reforming (SR) using a rotating discharge reactor. The process efficiency is described in terms of methane conversion, SR selectivity, energy input and hydrogen production cost. The experiments clearly demonstrated the ability of glidarc to accelerate chemical reactions at low temperatures and with very low energetic costs. A good approximation model describing the chemical processes on the basis of classical thermodynamics is also proposed. The analysis gives information on reactor design in order to improve its chemical performances. 相似文献
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Lin Li Luming Zhang Xiaofeng Shi Yuhua Zhang Jinlin Li 《Journal of Porous Materials》2014,21(2):217-224
In this paper, ordered mesoporous MgO nanocrystals [MgO(M)] were synthesized, and the nickel catalysts supported on MgO(M) were facilely prepared by impregnation method. The obtained Ni/MgO(M) catalysts with advantageous textural properties were investigated as the catalysts for the carbon dioxide reforming of methane reaction. It was found that compared with the Ni/MgO(C) catalyst [MgO(C): commercial MgO], the mesoporous pore structure of MgO(M) could effectively limit the growth of the activity metal, and the Ni/MgO(M) catalysts showed high catalytic activities as well as long catalytic stabilities toward this reaction. The results showed that the conversions of CH4 and CO2 were only decreased <5 % after 100 h of reaction at 650 °C. The improved catalytic performance was suggested to be closely associated with both the advantageous structural properties, such as large specific surface area, uniform pore size, and the “confinement effect” of the mesoporous matrixes contributed to stabilize the Ni active sites during the reaction. The carbon species deposited on the spent Ni/MgO(M) catalyst were analysized by TG and Raman, and the results exhibited that the carbon species after 100 h of reaction were mainly active carbon species. 相似文献
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Carbon dioxide reforming of methane to synthesis gas has been investigated over supported Ni catalysts in the temperature range of 500–850°C. Addition of CaO (10mol%) promoter to the Ni/γ-Al2O3 resulted in an increase of reaction rate and an improvement of catalyst stability, which may be related to enhanced reducibility of the promoted catalyst. The kinetic studies show that the overall reaction can be described by a Langmuir-Hinshelwood mechanistic scheme, assuming that methane dissociation is the rate determining step. In addition to adsorbed CO and formate species, three types of carbonaceous species, C, Cβ and Cγ, were found to exist on the Ni catalyst. While the active C, species is suggested to be responsible for CO formation, the less active Cβ and Cγ species are attributed to causing catalyst deactivation. 相似文献