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71.
在自制催化剂上进行了甲烷氧化制合成气工艺 30 0m3 /d规模的扩大实验。实验表明在原料气中加入少量水蒸气抑制了反应初期表面Ni晶粒的烧结 ,尤其是抑制了床层上部催化剂Ni晶粒的烧结 ,提高催化剂活性 ,甲烷转化率、CO和H2 选择性分别可达到 94%~ 96 %、90 %~ 92 %、94%~ 99% ;在V(CH4 ) /V(O2 ) /V(H2 O) =1 90 / 1/ 0 2 2、干气空速 1 3× 10 5/h、310m3 /d规模 2 0 0h寿命实验中 ,甲烷转化率和CO选择性均大于 90 % ,而H2 选择性高达 99%以上 ,催化剂显示了较好的活性和稳定性 ;实验也表明在高密度放热状态下 ,甲烷催化部分氧化制合成气工艺具备可操作性和工业化潜力 ,但工艺参数的优化有赖于工程模型的建立 ,需要进一步的扩大实验。 相似文献
72.
试验研究了木屑在水蒸气气氛下的热失重行为及气化过程中合成气释放特性。首先采用TG-DTA对木屑样品进行了水蒸气气氛下的热重行为分析,结果表明,木屑气化过程可以分为挥发分释放和半焦气化两个阶段,分别可由二级反应动力学和三维扩散Ginstling-Broushtein方程描述,对应的表观活化能分别为87.014kJ/mol和103.35 kJ/mol。此外,在自制的固定床气化反应装置上,研究了生物质气化过程中挥发分释放和半焦气化阶段合成气释放特性。另外,半焦水蒸气气化阶段对气体中合成气含量和H2/CO起到决定性作用,通过合理调控半焦气化阶段反应条件,可以得到合适化学当量比的生物质合成气。 相似文献
73.
《International Journal of Hydrogen Energy》2022,47(79):33664-33676
Strontium ferrite (SrFeO3-δ) is a very attractive oxygen transfer agent for chemical looping reactions and hydrogen-rich syngas generation. Dispersing SrFeO3 in a medium such as Ca0.5Mn0.5O could enhance the activity and cyclability. In this study, SrFeO3-δ-Ca0.5Mn0.5O (30 wt% SrFeO3-δ) nanocomposite with a reticulated foam structure was explored as the oxygen carrier for chemical looping reforming of methane in a solar tubular reactor. The foam nanocomposite was prepared by a hard-templating method. The performance was investigated at temperatures of 850–1000 °C and methane flowrates of 25–250 STP mL/min, and the oxidative gas was either CO2 or H2O in the oxidation step. In the reduction step of 27 successive redox cycles, the production rate of CO changed marginally and CO yield maintained at about 1.9 mmol/g, even though sintering occurred. The productivity of H2 decreased first and then tended to be stable at 3.8 mmol/g (i.e., twice the CO yield) as the cycling number increased (the average oxygen storage capacity of the material was ~1.95 mmol/g). Microscopic and X-ray diffraction investigations suggested that the element distribution pattern and crystalline phase of the foam nanocomposite remained almost unchanged after 27 redox cycles, confirming material stability. The maximum solar-to-fuel efficiency for the foam nanocomposite was 5.68%, which was 21.4% higher than that for the powder nanocomposite. To increase syngas productivity and solar-to-fuel efficiency, it is required to conduct the reforming reaction at high temperatures and methane flowrates. However, the energy upgrade factor will decrease as methane flowrate increases. 相似文献
74.
Dr. Sivaraman Balasubramaniam Dr. Sneh Badle Dr. Swati Badgujar Dr. Vinod P. Veetil Dr. Vidhya Rangaswamy 《Chembiochem : a European journal of chemical biology》2021,22(4):705-711
A method for producing buta-1,3-diene (1,3-BD) by an amalgamation of chemical and biological approaches with syngas as the carbon source is proposed. Syngas is converted to the central intermediate, acetyl-CoA, by microorganisms through a tetrahydrofolate metabolism pathway. Acetyl-CoA is subsequently converted to malonyl-CoA using a carbonyl donor in the presence of a carboxylase enzyme. A decarboxylative Claisen condensation of malonyl-CoA and acetaldehyde ensues in the presence of acyltransferases to form 3-hydroxybutyryl-CoA, which is subsequently reduced by aldehyde reductase to give butane-1,3-diol (1,3-BDO). An ensuing dehydration step converts 1,3-BDO to 1,3-BD in the presence of a chemical dehydrating reagent. 相似文献
75.
生物质合成气的化学当量比调整 总被引:1,自引:1,他引:1
针对生物质气化气中硫化物少、V(H2/CO)低和V(CO2)高的特点,采用气化炉内铁系高温变换催化剂和气化炉外钛促进的钴钼耐硫催化剂进行水煤气变换调整H2/CO比,添加部分沼气重整过量CO2,对生物质合成气化学当量比调整进行了实验研究。结果表明:气化炉内铁系催化剂调整效果不明显;在高温低硫的生物质气化气中,钛促进的钴钼耐硫催化剂具有较高的变换活性,CO转化率达到80%以上,合成气H2/CO比在1-8范围内可调;在V(CH4,CO2)=1、常压、750℃和镍基催化剂作用下沼气重整过量CO2,制备出宽V(H2/CO)、V(CO2)和V(CH4)均低于5%(摩尔百分比)的合成气;通过水煤气变换过程结合沼气重整过程,可依据目的产物合成的要求,制备合适化学当量比、高碳转化率的生物质合成气。 相似文献
76.
Dynamic Matrix Control of a Bubble‐Column Reactor for Microbial Synthesis Gas Fermentation 下载免费PDF全文
A spatiotemporal metabolic model of a representative syngas bubble‐column reactor was applied to design and evaluate dynamic matrix control (DMC) schemes for regulation of the desired by‐product ethanol and the undesired by‐product acetate. This model was used to develop linear step response models for controller design and also served as the process in closed‐loop simulations. A 2 × 2 DMC scheme with manipulation of the liquid and gas feed flows to the column provided a superior performance to proportional integral (PI) control due to slow process dynamics combining the multivariable and constrained nature of the control problem. Ethanol concentration control for large disturbances was further improved by adding the flow of a pure hydrogen stream as a third manipulated variable. The advantages of DMC for syngas bubble‐column reactor control are demonstrated and a design strategy for future industrial applications is provided. 相似文献
77.
我国乙二醇对外依存度居高不下,而富煤少油的资源特性使得我国煤制乙二醇技术具有较好的成本与原料优势,发展迅速。本文综述了国内外煤制乙二醇技术的技术现状和发展趋势,重点介绍了煤气化、草酸二甲酯合成和乙二醇合成与精制等关键单元技术的技术特征、工艺流程和技术进展,并分析了相关单元对整个煤制乙二醇系统技术经济性能的影响。针对现有煤制乙二醇技术存在能耗高、质能效率低和CO2排放大的问题,着重讨论了集成CO2高效利用的煤与富氢资源联供制乙二醇集成工艺的进展,包括耦合焦炉气、页岩气和绿氢等资源的新工艺等。以焦炉气为例,集成不同重整技术的新工艺使得传统工艺的碳效率和?效率分别提升了23.35%~39.17%和4.25%~10.12%,生产成本降低了8.73%~19.88%,内部收益率提高了3.6%~9.6%。因此,集成富氢资源与CO2高效利用的煤制乙二醇创新工艺是该行业向高效-经济-清洁可持续发展的重要方向。 相似文献
78.
Suk‐Hwan Kang Jin‐Ho Kim Ki‐Jin Jung Young‐Don Yoo Kwang‐Jun Kim Dong‐Jun Koh Jae‐Hong Ryu 《国际能源研究杂志》2017,41(3):353-364
In synthetic natural gas (SNG) reaction process, the water gas shift (WGS) reaction and methanation reaction take place simultaneously, and an insufficient supply of steam might deactivate the catalyst. In this study, the characteristics of the methanation reaction with a commercial catalyst and using a low [H2]/[CO] mole ratio in SNG synthesis are evaluated. The reaction characteristics at various possible process parameters are evaluated varying different process parameters such as the [H2O]/[CO] mole ratio, [H2]/[CO] mole ratio, flow of different % CO2, and reaction temperature. Temperature profiles on catalyst bed are monitored as a function of the [H2O]/[CO] mole ratio, [H2]/[CO] mole ratio, and flow of different % CO2. Through a lab‐scale optimization process, suitable optimum conditions are selected and in the same condition a 50‐kW pilot‐scale SNG production process through adiabatic reactors is carried out. The pilot scale SNG reaction is stable through overnight and the CO conversion efficiency and CH4 selectivity are 100% and 97.3%, respectively, while the maximum CH4 productivity is 0.654 m3/kgcat · h. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
79.
Medhat A. Nemitallah Mohamed A. Habib Hassan M. Badr Syed A. Said Aqil Jamal Rached Ben‐Mansour Esmail M. A. Mokheimer K. Mezghani 《国际能源研究杂志》2017,41(12):1670-1708
The increased level of emissions of carbon dioxide into the atmosphere due to burning of fossil fuels represents one of the main barriers toward the reduction of greenhouse gases and the control of global warming. In the last decades, the use of renewable and clean sources of energies such as solar and wind energies has been increased extensively. However, due to the tremendously increasing world energy demand, fossil fuels would continue in use for decades which necessitates the integration of carbon capture technologies (CCTs) in power plants. These technologies include oxycombustion, pre‐combustion, and post‐combustion carbon capture. Oxycombustion technology is one of the most promising carbon capture technologies as it can be applied with slight modifications to existing power plants or to new power plants. In this technology, fuel is burned using an oxidizer mixture of pure oxygen plus recycled exhaust gases (consists mainly of CO2). The oxycombustion process results in highly CO2‐concentrated exhaust gases, which facilitates the capture process of CO2 after H2O condensation. The captured CO2 can be used for industrial applications or can be sequestrated. The current work reviews the current status of oxycombustion technology and its applications in existing conventional combustion systems (including gas turbines and boilers) and novel oxygen transport reactors (OTRs). The review starts with an introduction to the available CCTs with emphasis on their different applications and limitations of use, followed by a review on oxycombustion applications in different combustion systems utilizing gaseous, liquid, and coal fuels. The current status and technology readiness level of oxycombustion technology is discussed. The novel application of oxycombustion technology in OTRs is analyzed in some details. The analyses of OTRs include oxygen permeation technique, fabrication of oxygen transport membranes (OTMs), calculation of oxygen permeation flux, and coupling between oxygen separation and oxycombustion of fuel within the same unit called OTR. The oxycombustion process inside OTR is analyzed considering coal and gaseous fuels. The future trends of oxycombustion technology are itemized and discussed in details in the present study including: (i) ITMs for syngas production; (ii) combustion utilizing liquid fuels in OTRs; (iii) oxy‐combustion integrated power plants and (iv) third generation technologies for CO2 capture. Techno‐economic analysis of oxycombustion integrated systems is also discussed trying to assess the future prospects of this technology. Copyright © 2017 John Wiley & Sons, Ltd. 相似文献
80.
Yun Gao Babak Ghorbanian Hossein Najari Gargari Wei Gao 《Petroleum Science and Technology》2017,35(21):2074-2079
An important step in developing clean energy and reducing greenhouse gas emissions is the use of clean technologies such as gasification. In this work, we were used a bubbling fluidized bed (BFB) to convert the bitumen oil into a clean syngas in presence of three kinds of Ni/dolomite catalysts. While all three catalysts were acceptable in the process of tar elimination, but DN-22 was more successful in eliminating tar than the other two samples, which might be due to the higher amount of CaO in the composition DN-22. With increase in Ni, the amount of eliminated tars in the tar cracking process was also increased due to the delay in the deactivation of the dolomite catalyst. 相似文献