利用“清洁发展机制”促进山西煤层气开发

山西省蕴藏着丰富的煤层气资源,合理利用煤层气资源不仅是对能源的补充,也对减轻温室效应起着重要作用。介绍了山西省正在进行的清洁发展机制CDM项目和CO2减排购买意向项目。分析看出,山西省目前井下瓦斯利用和地面煤层气利用可以产生良好的环境效益,煤层气减排市场可获得巨大的经济效益。指出了目前山西省CDM项目申报中存在的问题及未来发展的方向,分析了未来大规模开采利用煤层气所带来的CO2减排市场的巨大潜力。     

Oxidative coupling of methane in a bubbling fluidized bed reactor

The oxidative coupling of methane to higher hydrocarbons (C₂₊) was studied in a bubbling fluidized bed reactor between 700°C and 820°C, and with partial pressures of methane from 40 to 70 kPa and of oxygen from 2 to 20 kPa; the total pressure was ca 100 kPa. CaO, Na₂CO₃/CaO and PbO/γ-Al₂O₃ were used as catalytic materials. C₂₊ selectivity depends markedly on temperature and oxygen partial pressure. The optimum temperature for maximizing C₂₊ selectivity varies between 720 and 800°C depending on the catalyst. Maximum C₂₊ selectivities were achieved at low oxygen and high methane partial pressures and amounted to 46% for CaO (T = 780°C; P_CH4 = 70 kPa; P_O2 = 5 kPa), 53% for Na₂CO₃/CaO (T = 760°C; P_CH4 = 60 kPa; P_O2 = 6 kPa) and 70% for PbO/γ-Al₂O₃ (T = 720°C; P_CH4 = 60 kPa; P_O2 = 5 kPa). Maximum yields were obtained at low methane-to-oxygen ratios; they amounted to 4.5% for CaO (T = 800°C; P_CH4 = 70 kPa; P_O2 = 12 kPa), 8.8% for Na₂CO₃/CaO (T = 820°C; P_CH4 = 60 kPa; P_O2 = 20 kPa) and 11.3% for PbO/γ-Al₂O₃ (T 2= 800°C; P_CH4 = 60 kPa; P_O2 = 20 kPa).     

水合物法分离低浓度煤层气中的甲烷

向模拟煤层气(13.11vol% CH4+86.89vol% N2)中添加5.8mol%四氢呋喃(THF)?0.03mol%十二烷基硫酸钠(SDS)促进剂溶液分离提纯煤层气,考察了压力、温度、反应时间对气体消耗量、反应速率、分解气中甲烷浓度、甲烷回收率和甲烷分离因子的影响,采用色谱分析法分别测定了CH4在剩余气相和分解气相中的浓度。结果表明,压力增加,CH4回收率增大,CH4分离因子增大,CH4分离效果越好;温度是影响甲烷分离因子的关键因素,温度降低,氮气和甲烷竞争进入水合物晶体中,导致水合物相中甲烷浓度降低;温度升高有利于提高水合物对甲烷的选择性。甲烷回收效率最高可达98.65%,分离因子最大为14.83。随反应时间增加,分解气中CH4浓度升高。     

低浓度煤层气分离提纯的研究进展

综述了应用于低浓度煤层气分离的主要方法,包括低温精馏法、吸附分离法、膜分离法和水合物法,探讨了各种方法在不同工艺条件下的分离效果,分析了它们的优缺点。文中总结了每种方法需要解决与突破的关键性问题：低温精馏法获得的甲烷浓度高,但在处理含氧煤层气时首先要脱氧;吸附分离的关键技术在于吸附剂的选择,吸附剂决定了该方法的经济效益与难易程度;对于膜法分离,影响煤层气分离效果的主要因素在于膜材料的选择及制膜工艺;对于水合物法,寻找制备具有较高分离效率的添加剂是关键。最后指出,多种方法结合、多级分离的分离方法是未来研究发展方向。     

煤层气水合化的基础研究

自行设计制造了一套可用于煤层气水合物生成与分解的可视化实验系统,利用该实验系统研究了阴离子表面活性剂、非离子表面活性剂和多孔介质煤对煤层气水合物生成的影响,进行了煤层气水合物生成相平衡参数和分解热力学方面的研究。结果表明:表面活性剂的加入促进了水合物的生长,但水合物的生成情况与表面活性剂的种类和浓度有关;表面活性剂的加入有效地改变了水合物生成的热力学条件;水合物分解过程所需热量较多,证实了利用煤层气水合化技术预防煤矿煤与瓦斯突出以及进行煤层气固化储运的可行性。     

Evaluation of gas content of coalbed methane reservoirs with the aid of geophysical logging technology

The geophysical logging technology has been employed in connection with field and laboratory tests for coal reservoir evaluation in Huainan and Huaibei coalfields, China. The relationships between coalbed gas content of coal reservoir and characteristics of geophysical logs have been investigated by means of the combined analyses of experimental and geophysical logging data. Coalbed gas content of drilling core samples from coal seams was determined experimentally. The results, together with the log data obtained from geophysical logging technology, have been analyzed by using geological statistics, permitting correlation of the coalbed gas content to the log responses. The correlation developed in this study provides better understanding of the coal reservoir for coalbed methane exploration in given coalfields by an improved prediction of the coalbed gas content.     

煤制合成天然气现状及其发展

随着人们对天然气需求的快速增长,煤制天然气技术受到越来越多的关注,而煤制天然气的核心技术是甲烷化技术。对煤制合成天然气的国内外发展现状进行了介绍,并对甲烷化技术需要解决的关键技术及其发展提出了自己的见解。     

贵州省煤层气地质条件及开发利用现状

贵州煤层气资源丰富,笔者在分析了贵州省煤层气地质条件的基础上,得出影响煤层气开发的主要因素是复杂的地形条件;煤层气开采成本较高,且成品价格较低;煤层气与煤炭矿权没有分离是导致煤层气不能有效利用的主要原因,解决这些问题的主要措施是尝试煤层气的井下液化,国家重点扶持大型企业等。     

地球物理技术在煤层气勘探中的应用

煤层气的勘探对于优化能源结构、保障煤矿安全、减少温室气体排放等具有重要意义。基于煤储层的方位各向异性和双相介质特征,方位AVO、转换横波法和AVO等地震勘探技术能够对煤层气富集区做出有效预测。测井技术具有方法种类多、分辨率高等特点,在煤层气储层识别和储层参数定量解释方面取得了较好的应用效果。开展地震技术和测井技术的综合利用是今后煤层气勘探技术的发展方向。     

A review on transport of coal seam gas and its impact on coalbed methane recovery

This paper presents a summary review on mass transport of coal seam gas (CSG) in coal associated with the coalbed methane (CBM) and CO₂ geo-sequestration enhanced CBM (CO₂-ECBM) recovery and current research advances in order to provide general knowledge and fundamental understanding of the CBM/ECBM processes for improved CBM recovery. It will discuss the major aspects of theory and technology for evaluation and development of CBM resources, including the gas storage and flow mechanism in CBM reservoirs in terms of their differences with conventional natural gas reservoirs, and their impact on CBM production behavior. The paper summarizes the evaluation procedure and methodologies used for CBM exploration and exploitation with some recommendations.     

Synthesis gas formation by direct oxidation of methane over Rh monoliths

The production of H₂ and CO by catalytic partial oxidation of CH₄ in air or O₂ at atmospheric pressure has been examined over Rh-coated monoliths at residence times between 10^–4 and 10^–2 s and compared to previously reported results for Pt-coated monoliths. Using O₂, selectivities for H₂ ( ) as high as 90% and CO selectivities (S _CO) of 96% can be obtained with Rh catalysts. With room temperature feeds using air, Rh catalysts give of about 70% compared to only about 40% for Pt catalysts. The optimal selectivities for either Pt or Rh can be improved by increasing the adiabatic reaction temperature by preheating the reactant gases or using O₂ instead of air. The superiority of Rh over Pt for H₂ generation can be explained by a methane pyrolysis surface reaction mechanism of oxidation at high temperatures on these noble metals. Because of the higher activation energy for OH formation on Rh (20 kcal/mol) than on Pt (2.5 kcal/mol), H adatoms are more likely to combine and desorb as H₂ than on Pt, on which the O+ H OH reaction is much faster.This research was partially supported by DOE under Grant No. DE-FG02-88ER13878-AO2.     

煤层气开发利用的制约因素及对策

介绍了中国煤层气资源状况及开发利用现状,在此基础上分析了制约中国煤层气资源开发利用的不利因素,并针对这些制约因素提出了解决对策,为加快中国煤层气开发利用提供了思路。     

Catalytic combustion of natural gas as the role of on-site heat supply in rapid catalytic CO2---H2O reforming of methane

Development in highly active catalysts for the reforming of methane with H₂O, CO₂, and H₂O+CO₂, and partial oxidation of methane was conducted to produce hydrogen with high reaction rates. A Ni-based three-component catalyst such as Ni---La₂O₃---Ru or Ni---Ce₂O₃---Pt supported on alumina wash-coated ceramic fiber in a plate shape was very suitable for both reactions. The catalyst composition was set at 10 wt.-% Ni, 5.6 wt.-% La₂0₃, and 0.57 wt.-% Ru for example, or molar ratios of these components were 1:0.2:0.03. Even with such a low concentration, the precious metal enhanced the reaction rate markedly, and this synergistic effect was ascribed to the hydrogen spillover effect through the part of precious metal and it resulted in a more reduced surface of the main catalyst component. In particular, a marked enhancement in the reaction rate of CO₂-reforming of methane was observed by the modification of a low concentration Rh to the Ni---Ce₂0₃---Pt catalyst. Very high space-time yields of H₂ (i.e., 8300 mol/1 h in partial oxidation of methane at 600°C with a methane conversion of 37.5%, and 3585 mol/1 h in CO₂reforming of methane at 600°C with a methane conversion of 58%) were realized in those reactions. By combining the catalytic combustion reaction, methane conversion to syngas was markedly enhanced, and even with a very short contact time (10 ms) the conversion of methane increased more than that at 50 ms. The space-time yield of hydrogen amounted to 2,780 mol/1 h with a methane conversion of 90% at 700°C. Furthermore, in a reaction of CH₄---CO₂---H₂O---O₂ on the four components catalyst, an extraordinarily high space-time yield of hydrogen, 12 190 mol/1 h, could be realized under the conditions of very high space velocity (5 ms).     

煤层气脱氧剂的研究进展

阐述了燃烧脱氧、催化氧化、化学吸收法等3种脱氧机理,主要综述了贵金属、铜系、铁系、锰系、钼系以及多孔陶瓷材料等相关脱氧剂的制备工艺、脱氧原理和研究现状。通过对比不同脱氧剂的制备成本以及脱氧效果、后处理程序等,指出各种脱氧剂的优缺点。其中贵金属脱氧剂脱氧效果最好,但消耗甲烷、氢气等还原气体,且产生CO₂/H₂O等杂质;非贵金属脱氧剂价格低廉,但脱氧效果略差,使用温度相对较高;非金属型脱氧剂具有不易硫中毒等优缺点。最后,综合前述脱氧剂的特点,提出脱氧剂的两个发展方向,即非金属脱氧剂和具有较强吸附、催化性能的复合型脱氧剂。     

大型煤化工企业制冷工艺选择

煤制天然气项目对天然气的净化是一个较大的问题,在这其中如何给低温甲醇洗、甲烷化工序提供冷量是一个关键的因素,对投资额的大小、投产后的经济效益有较大的影响,混合制冷方法是几种制冷手段中比较合适的手段     

Cu/γ-Al2O3 catalyst for the combustion of methane in a fluidized bed reactor

The applicability of a catalyst based on copper dispersed on γ-Al₂O₃ spheres (1 mm diameter) for fluidized bed catalytic combustion of methane has been assessed. Catalyst properties have been determined by physico-chemical characterization techniques and fixed bed activity tests revealing the presence of a surface CuAl₂O₄ spinel phase, still active and stable in methane combustion after repeated thermal ageing treatments at 800 °C. Methane catalytic combustion experiments have been performed in a 100 mm premixed fluidized bed reactor under lean conditions (0.15–3% inlet methane concentration), showing that complete CH₄ conversion can be attained below 700 °C in a fluidized bed of 1 mm solids with a gas superficial velocity about twice the incipient fluidization velocity.     

利用煤层气发展山西化工

煤层气是近30年开始开发与应用的新能源,是非常规天然气,其主要成分为甲烷,山西省地下煤层气可彩资源约9000亿m^3,按热值换算相当于11.7亿t煤炭。利用煤层气制造合成气发展化学工业,成本低,污染轻。     

Devolatilization of coals of northeastern India in inert atmosphere and in air under fluidized bed conditions

Devolatilization of five coals having volatile matter in the range of 31 to 41% was studied in argon and in air under fluidized bed conditions. The diameter of the coal particles varied between 4 and 9.5 mm. The variation of devolatilization time with particle diameter was expressed by the correlation, t_v = Ad_vⁿ. The superficial gas velocity was found to have a significant effect on the rate of devolatilization. The devolatilization rate increased with the increase in the oxygen concentration in the fluidizing gas. The correlations developed in this study fitted the mass versus time profiles of the coal particles satisfactorily. The same correlations were found to be appropriate for predicting devolatilization of a batch of coal particles. The correlations developed in the present study will be useful for the design of fluidized bed combustors.     

晋城矿区煤层气发电现状及规划

晋城矿区赋有丰富的煤层气资源 ,为充分利用这部分煤层气资源 ,晋城无烟煤矿业集团利用美国的打钻、压裂、排采技术实施煤层气开发示范工程 ,经潘庄、寺河两矿煤层初步发电试验 ,取得成功 ,2 0 0 2年初运转的 1 1× 1 0 4kW发电示范工程 ,取得良好的经济效益 ,为后续煤层气资源利用积累了宝贵的经验。