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11.
Effect of O2 and H2O on the tri-reforming of the simulated biogas to syngas over Ni-based SBA-15 catalysts 总被引:2,自引:0,他引:2
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A series of Ni/SBA-15 catalysts with Ni contents from 7.5 wt% to 15 wt% were prepared by impregnation method. The effect of O2 and H2O on the combined reforming of the simulated biogas to syngas was investigated in a continuous flow fixed-bed micro-reactor. The stability of the catalyst was tested at 800 ℃. The results indicated that 10 wt%Ni/SBA-15 catalyst exhibited the highest catalytic activities for the combined reforming of the simulated biogas to syngas. Under the reaction conditions of the feed gas molar ratios CH4/CO2/O2/H2O = 2/1/0.6/0.6, GHSV = 24000 ml•g{cat}-1\cdoth-1 and the reaction temperatureT = 800 ℃, the conversions of CH4 and CO2 were 92.8% and 76.3%, respectively, and the yields of CO and H2 were 99.0% and 82.0%, respectively. The catalytic activities of the catalyst did not decrease obviously after 100 h reaction time on stream. 相似文献
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中国中部规模养殖沼气工程系统顶点赋权图分析 总被引:9,自引:1,他引:8
基于系统动力学反馈分析理论,提出定性与定量紧密结合的系统顶点赋权因果关系图分析法。以萍乡地区兰坡村泰华猪场规模养殖沼气工程系统为实例,对我国中部农村生猪养殖沼气工程系统的利润、粪尿等废弃物二次生物质再生能源开发、沼肥对水稻和蔬菜种植促进的正效益以及过剩招气对大气的污染、沼液与灌溉用水混合排灌造成水稻苗发青、由于承载沼肥的农田不足和长达七个月的冬闲季节沼肥浪费引发的二次污染等问题进行定量动态反馈分析研究,得出系统蕴含的四条增长、四条制约反馈环的反馈规律。给出针对我国中部地区小流域地域特征的,有利于规模养殖系统可持续发展的沼气工程系统建设的三条对策建议。 相似文献
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Jinglin Liu Xiaobing Zhu Xiaosong Li Kai Li Chuan Shi Aimin Zhu 《Journal of Energy Chemistry》2013,22(5):681-684
In a novel plasma-shade reactor for oxidative reforming of biogas (CH4/CO2 = 3/2), the effects of specific-energy-input (SEI) on CH4 and CO2 conversions and energy cost of syngas were investigated at O2/CH4 ratios ranged from 0.42 to 0.67. At each of O2/CH4 ratios, V-shape profiles of energy cost of syngas increasing with SEI were observed, reaching the lowest value at the optimal SEI (Opt-SEI). With the increase of O2/CH4 ratio, the Opt-SEI decreased significantly. Moreover, at the Opt-SEI, O2 and CH4 conversions and dry-basis concentration of syngas increased and energy cost of syngas decreased greatly with the increase of O2/CH4 ratio. 相似文献
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CO2 capture by hydrate formation is a novel gas separation technology, by which CO2 is selectively engaged in the cages of hydrate and is separated with other gases, based on the differences of phase equilibrium for CO2 and other gases. However, rigorous temperature and pressure, high energy cost and industrialized hydration separator dragged the development of the hydrate based CO2 capture. In this paper, the key problems in CO2 capture from the different sources such as shifted synthesis gas, flue gas and sour natural gas or biogas were analyzed. For shifted synthesis gas and flue gas, its high energy consumption is the barrier, and for the sour natural gas or biogas (CO2/CH4 system), the bottleneck is how to enhance the selectivity of CO2 hydration. For these gases, scale-up is the main difficulty. Also, this paper explored the possibility of separating different gases by selective hydrate formation and reviewed the progress of CO2 separation from shifted synthesis gas, flue gas and sour natural gas or biogas. 相似文献
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Grzegorz Piechota Roman Buczkowski 《International journal of environmental analytical chemistry》2013,93(8):837-851
By empirically examining the persistent theme, we hope to produce a more complete understanding of methods for determination of volatile methylsiloxanes in biogas stream. Therefore, we made an attempt to investigate a rapid and sensitive method for simultaneous analysis of linear and cyclic volatile methylsiloxanes in sewage biogas in the context of the perspective for application in online systems. The gas chromatographic (GC) parameters were optimised, and sampling of volatile methylsiloxanes from biogas was performed using novel direct sampling procedure with applying of three kinds of liquid-media. Through application of well-established gas chromatography technique coupled with two types of detector – flamed ionisation detector and mass spectrometer detector – we developed the characterisation of the presented methods. Moreover, during the samples preparation the extraction procedure was consistently excluded, as well as the time of analysis was significantly reduced. The analyses were carried out by applying special constructed sampling train where the absorbed VMSs were trapped and analysed directly by GC technique, afterwards. The instrumental analytical protocol was found to yield a linear calibration in the range 0.1–55.13 (µg g?1) with R2 values 0.996 and in the range from 0.1 to 65.17 µg g?1) with R2 values > 0.99 for GC-FID and GC-MS method respectively. In all analysed samples linear and cyclic VMSs were found in sewage gas with quantities exceeding 4.6 mg Nm?3 and 19.9 mg Nm?3, respectively Furthermore, estimation of VMSs solvent absorption efficiency was tested and the highest absorption efficiency was obtained when acetone was used as a primary solvent. High range of linearity (0.1–65.17 µg/g), and low values of limit of detection (0.01 µg/g), limit of quantification (0.04 µg/g) clearly indicate that the analysis can be successfully repeated in other independent laboratory. The proposed method creates the real perspective for analyis of VMSs in on-line system. 相似文献
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Eva Gallego Francisco Javier Roca José Francisco Perales Xavier Guardino Enrique Gadea 《International journal of environmental analytical chemistry》2015,95(4):291-311
An analytical method based on TD-GC/MS was developed and validated for the determination of volatile organic compounds (VOCs), including linear and cyclic volatile methylsiloxanes (VMSs), in biogas. Biogas was first sampled in Supel? Inert Film bags and subsequently dynamically sampled onto multisorbent bed tubes (Carbotrap, Carbopack X and Carboxen 569) using portable pump equipment. Two sample volumes, 100 and 250 ml, were evaluated. Desorption efficiency values for both volumes are in the range of 99–100% for almost all studied compounds while breakthrough values (%VOC on sample tube back section) are below 1% for most evaluated VOCs. However, acetaldehyde, carbon disulphide, ethanol and 1,3-butadiene have breakthrough values higher than 5%. Method detection limits were in the range of 0.01–0.8 ng per sample. The most abundant VOCs in biogas were terpenes with concentrations between 500 and 700 mg m?3. Other important families were ketones, aromatic hydrocarbons and alkanes, with concentrations in the range of 36–46 , 20–35 and 14–16 mg m?3, respectively. VMSs presented average concentrations of 4.9 ± 0.4 mg m?3. Additionally, the Supel? Inert Film bags were evaluated for stability for 4 days at room temperature. Although several VOC families’ concentrations in the bag increased or decreased significantly (t-test; p ≤ 0.01, n = 5) 2 days after collection, recoveries were around 70–130% for most studied VOCs. The results shown demonstrate that the presented methodology is reliable and satisfactory for the evaluation of VOCs in biogas and presents an alternative to the currently existing biogas analytical techniques. 相似文献
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Grzegorz Piechota Bartłomiej Igliński Roman Buczkowski 《International journal of environmental analytical chemistry》2015,95(9):867-877
This paper reports on an absorption method used for the determination of six target volatile methylsiloxanes and trimethylsilanol existing in raw biogas samples by means of a special and portable sampling train system. After biogas sampling (no accurate pump needed), the samples obtained were analysed by gas chromatography-mass spectrometry (GC-MS). The optimisation of the used solvent was carried out, and acetone was selected as the preferred liquid medium for trapping the siloxanes. The results clearly showed that using pure acetone and a mixture of acetone and water (97/3% = v/v) ensures very good solvation of silicon-contained molecules; thus the sampling procedure was more accurate. Replicate samples showed that the relative standard deviation of the method was less than 5.7% and 6.3% for methylsiloxanes as well as less than 2.1% and 2.4% for trimethylsilanol analysed 24 and 72 hours after sampling, respectively. Furthermore, limits of detection were determined theoretically and experimentally. The limits of detection for siloxanes and trimethylsilanol were in the range 0.04–0.11 mg/Nm3 and 0.08–0.12 mg/Nm3, respectively. The limit of quantification for trimethylsilanol was 0.1 mg/Nm3, whereas the limit for siloxanes ranged from 0.1 to 0.13 mg/Nm3. Finally, raw biogas samples were successfully analysed by the developed method. Trimethylsilanol and methylsiloxanes were found in the concentrations of 34.5 mg/Nm3 and 1.7–20 mg/Nm3 in the analysed raw biogas, respectively. 相似文献