混合原料在不同发酵工况下的产气规律研究

分别在五种不同条件下进行了沼气产气对比试验。试验条件分别为:干牛粪,温度为20℃,排气方式分别为持续排气、间歇排气(每天排气4次);干牛粪,温度为35℃,排气方式分别为持续排气、间歇排气;干牛粪与小麦秸秆按质量比1∶1配比的混合物,温度为35℃,排气方式为间歇排气。将原料装入100 L自动生物发酵罐中,并控制发酵温度和压力,检测发酵过程中沼气的日产气量、料液pH及产气中甲烷体积分数。结果发现,在间歇排气条件下,干牛粪与小麦秸秆混合物与相同质量的干牛粪相比总产气量提高约20%,但日产气量降低,产气周期延长近40%。相同质量的干牛粪,在35℃时发酵与在20℃时发酵相比总产气量提高约35%,高峰产气速度提高约1倍;持续排气相比于间歇排气,日产气量提高约1倍,但甲烷平均体积分数降低约10%。     

贵州合层开发煤层气井产层孔渗特征研究

贵州省煤层发育,煤层气资源富集,对其合层开发煤层气产层孔渗特征进行研究能够为煤层气高产、稳产提供依据。基于贵州合层排采煤层气井产层特征统计,综合现有地质及工程数据,系统研究产层孔渗特征。研究结果表明：贵州境内受煤变质程度高的影响,煤层气产层孔隙度较低,主要在2% ～ 6%之间;煤储层大多发育两组相互近正交的内生裂隙,外生裂隙则与区内深大断裂活动以及煤层厚度有关;产层渗透率均低于0.35 mD,属于中低渗透率产层,且以小于0.1 mD的低渗产层为主。     

加快构建山西本省稳定气源

随着中国经济的发展及人们对环境保护认识的提高,清洁能源受到越来越广泛的关注,要发展更要环境的理念越来越深入人心。目前,山西正在实施＂气化山西＂战略,以实现清洁发展、低碳发展、绿色发展,立足于探讨建设山西本省稳定气源,确保足够的气源供应,筑牢山西经济社会发展的能源保障基石。     

沼气池产气率随气温地温变化规律的研究

为了准确掌握户用沼气池在不同模式条件下的产气能力,探讨其产气率率环境温度的关系,以便科学地评价其经济效益,更好地指导农户管理、使用沼气池,采用观察、记载统计方法,得到“四位一体”模式、“三结合”模式和露地池的产气量变化规律.     

国外煤层气生产概况及对加速我国煤层气产业发展的思考

我国煤层气资源丰富,埋深2000m以浅的煤层气资源量达到31．46×10^12m3;是世界第三大煤层气储藏国。加速我国煤层气产业发展,既有利于煤矿安全生产,增加洁净能源供应,也有利于减少温室气体排放。美国是煤层气产业发展最早、最快、最成功的国家,居世界领先地位,其煤层气产量从1985年的2．8×10^8m3;增加至2008年的493×10^8m3;加拿大的煤层气资源集中在西部的沉积盆地,以艾伯塔省为主,该省2008年产量达到73．4×10^8m3;我国目前已建成地面煤层气产能20×10^8m3;产量5×10^8m3;,民用煤层气用户超过90万户．煤层气发电装机容量达到92×104kW．2008年井下抽采瓦斯53×10^8m3;具体进展表现为山西煤层气顺利注入西气东输主干线,沁水盆地南部煤层气开发示范工程开始商业运营,煤层气进入规模化开发新阶段;与此同时,相关行业标准陆续出台,有关技术取得可喜进步。招商引资和对外合作也初见成效;国家还出台了一系列方针政策支持煤层气产业发展。但也存在一些亟待解决的问题．如探明储量仅占总资源量很少一部分,煤层气年商业产量不足4×10^8m3;,煤矿瓦斯平均抽出率仅23％等。国有企业应勇于承担加快我国煤层气产业发展的重任,加大人力、物力、财力投入,加快煤层气勘探开发步伐：科技创新方面应以重大科技专项为契机,尽快取得突破性进展;同时应进一步加速煤层气管网建设,加强招商引资和对外合作。     

Controlling Mechanism and Resulting Spray Characteristics of Injection of Fuel Containing Dissolved Gas

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The production of ultra-clean coal from Zonguldak bituminous coal by chemical leaching

From run-of-mine coal with an average ash of 50% being produced at Zonguldak coal basin, clean coal with 7% ash can be produced through physical enrichment methods such as jig and heavy media. However, for the production of coal with an ash content of lower than 7%, it is required for the coal to be first ground and then subjected to chemical leaching operation. In this study, chemical leaching tests were performed with aqueous HF, HCL, HNO₃, and citric acid (CA) in order to produce ultra-clean coal (UCC) from Zonguldak bituminous coal. The effects of type of chemical, grain size, temperature, and leaching time in the leaching process were studied. It was observed that UCC with 0.82% ash could be produced from sample coal with 8.84% ash as the result of leaching operation with aqueous HF.     

Synthesis gas and H2 production from solar gasification of albertan coal

A site-specific study has been carried out on the economics of commercial, hybrid solar and solar coal-gasification plants of 10⁷ GJ/yr capacity located at a coal field near Edmonton, Alberta.

It has been found that the gasification efficiencies have been improved by approx. 10% in hybrid solar gasification plants and by 25% in solar coal-gasification plants. As a result, the coal economy is from 12 to 30% for hybrid solar and solar plants. For typical values of $5/t coal price and 15% capital charge rates, the levelized^† costs of synthesis gas are estimated to be $6.76/GJ from the commercial Koppers-Totzek (K-T) process, $5.62/GJ from the commercial Lurgi process, $7.63/GJ from the hybrid solar K-T process, $10.75/GJ from the solar K-T process, $6.49/GJ from the hybrid solar Lurgi process and $10.15/GJ from the solar Lurgi process. For the same conditions, the estimated costs of H₂ are $7.89/GJ from the commercial K-T process, $8.77/GJ from the hybrid solar K-T process and $12.85/GJ from the solar K-T process.     

煤层气的运移机理及其强化抽采

煤层气是一种优质的洁净能源。在分析煤层气运移过程的基础上,建立了钻孔抽放煤层气的渗流运动方程,并求得其近似解析解。基于此,分析了煤层气抽采的主要影响因素,结果表明:增强煤层透气性,提高煤层压力,增大孔径和提高抽采负压都有利于促进煤层气的抽采。实际中,对于低渗煤层,应采取有效的强化措施,以提高煤层气的回收率。     

Batch analysis of H2-rich gas production by coal gasification using CaO as sorbent

In this study, a clean coal gasification technology was developed for production of H₂-rich gas from coal with CaO as sorbent. The conditions including [CaO]:[C] ratios, reaction temperature, and reaction time for the coal gasification process were optimized. The products were H₂, CH₄, CO, and CO₂. The highest H₂ percentage (82.66%) for bituminous coal was obtained at [CaO]:[C] = 2:1 and T = 1203 K. Meanwhile, the highest H₂ percentages for high-sulfur coal and high-sulfur coke were 77.41 and 81.57% at [CaO]:[C] = 1:4 and T = 1203 K, respectively. Moreover, the residual H₂S were 0.28 and 2.19%, correspondingly.     

褐煤热解提质系统的煤气净化及脱硫

对褐煤热解提质系统所生产的副产热解煤气进行了简要分析,并针对褐煤热解提质系统的特点提出了四种煤气净化工艺,同时对煤气脱硫工艺进行了简要介绍,提出了煤气净化与煤气脱硫合理结合的几点建议.     

A novel hydrogen production system based on the three-step coal gasification technology thermally coupled with the chemical looping combustion process

Coal gasification technology is a significant process for the coal-based hydrogen production system and is considered as a key technology in the transition to “Hydrogen Economy”. To decrease the exergy destruction and enhance the cold gas efficiency of the coal gasification process, a novel three-step gasification technology thermally coupled with the chemical looping combustion process is proposed. And the hydrogen production system with CO₂ recovery is integrated based on the three-step gasification technology. Results indicated that the cold gas efficiency of the three-step coal gasification technology is 86.9%, which is 10.1% points enhanced compared with GE gasification technology. Besides, the novel system has an energy efficiency of 62.3%, which is 3.1% higher than that of the reference system. Exergy analysis presented that the employment of the three-step gasification technology contributed to the reduction of system exergy destruction by 4.2%. Furthermore, the energy utilization diagram (EUD) suggested that matching between endothermic reactions and exothermic reactions plays important role in the enhancement of cold gas efficiency.     

Long term forecasting of natural gas production

Natural gas is an important energy source for power generation, a chemical feedstock and residential usage. It is important to analyse the future production of conventional and unconventional natural gas. Analysis of the literature determined conventional URR estimates of 10,700–18,300 EJ, and the unconventional gas URR estimates were determined to be 4250–11,000 EJ. Six scenarios were assumed, with three static where demand and supply do not interact and three dynamic where it does. The projections indicate that world natural gas production will peak between 2025 and 2066 at 140–217 EJ/y (133–206 tcf/y). Natural gas resources are more abundant than some of the literature indicates.     

Continuous method development and numerical study of HHV water gas production by pulverized coal

In energy industries,it is always of difficulty to produce high heat value(HHV) gas continuously using pulverized coal.In this paper,a new type furnace for partitioned alternative gasification using pulverized coal is developed,in which the oxidation and reduction reaction occur alternatively with the dropping of pulverized coal and finally HHV gas could be continuously obtained at the reduction zone exit and low heat value(LHV) gas at the oxidation zone exit.Furthermore,the gasification characteristics and their factors in furnace are numerically simulated under two dimensional model with a self-coded program,based on heat,mass and energy transfer as well as reaction principles.It is found that the producing rate of HHV gas is 1.10Nm3/kg with heat value of 11.72MJ/Nm3,however,that of LHV gas is 2.58Nm3/kg with heat value of 5.30MJ/Nm3,and the coal gas efficiency is 81.16% under optimized conditions.     

沼气重整制合成气技术可行性探讨

论述了沼气的组成和利用现状,通过天然气蒸汽重整中的加碳技术说明了沼气中二氧化碳的利用价值。借鉴天然气重整工业经验和模拟沼气重整的实验室研究,探讨了沼气重整制合成气技术的可行性,初步提出了沼气重整制合成气的试验方案。分析认为,沼气通过脱硫、脱氧、与水蒸气混合加热进行重整制合成气是提高沼气综合利用率的有效途径,为沼气重整制合成气工业研究提供了参考依据。     

Hydrogen production from coal using coal direct chemical looping and syngas chemical looping combustion systems: Assessment of system operation and resource requirements

Coal direct chemical looping (CDCL) substitutes the gasification process in syngas chemical looping (SCL), thus eliminating the need for higher oxygen consumption. In this study, operating conditions are assessed for CDCL and SCL, directed towards hydrogen production from coal. The main objective is to increase the overall H₂/CO₂ ratio for a given amount of coal, based on the various conditions. The operating variables considered as part of a resource optimization analysis include: (i) inlet conditions to the primary reactors, (ii) minimum resource requirements (air, steam and iron oxide), (iii) hydrogen-to-component ratios, and (iv) effect of coal carrier gas. The results suggest that CDCL has a higher hydrogen-to-CO₂ ratio than SCL along with advantages such as low overall resource requirements (steam and air) and fewer intermediate processes. The coal carrier gas affects the hydrogen production only in the SCL system by altering the composition of syngas induced by gasifier temperature variation.     

关于山西煤层气发电价格的调查

利用煤层气发电,对保护生态环境和优化能源产业结构都具有十分重要的意义。运用价格政策推进煤层气发电进程,当前要对煤层气产权进行政策界定,要合理解决煤矿企业和煤层气发电企业在已开采煤层气成本方面的矛盾,尽快落实国家鼓励煤层气发电的补贴政策,简化煤层气发电的上网程序,合理解决工业用气和生活用气的矛盾。     

Study of the crystal structure effect and mechanism during chemical looping gasification of coal

Chemical looping gasification (CLG) of coal, in which oxygen is provided to coal by oxygen carriers directly, is a clean and efficient way to generate syngas. Thermo-gravimetric analysis (TGA) of lignite char with oxygen carriers was conducted in this work, and the experimental results indicated that the oxygen carriers, Ti_0·5Mn_0·5Fe₂O₄, MnFe₂O₄, FeTiO₃ and Fe₂TiO₄, had a positive effect on CLG of lignite char. The effect of these oxygen carriers was discussed in the perspective of the crystal structure. XPS experiment was performed and the spectra of O 1s revealed the effect of different element on reactivity of spinel-based oxygen carriers. Five kinetic models, including Uniform Reaction (UR), Integrated Model (IM), Modified Random Pore Model (MRPM), Random Pore Model (RPM) and Modified Volumetric Model (MVM), were employed for revealing the reaction mechanism. MRPM had the highest correlation coefficient for each oxygen carrier, which means the introduction of the oxygen carriers effectively increases the active site of the reaction surface.     

Study the reaction mechanism of catalytic reforming of acetic acid through the instantaneous gas production

In order to study the reaction mechanism of steam reforming of bio-oil, acetic acid was selected as the model compound and Ni/Al₂O₃ as the catalyst to carry out a series of experiments. Through the comparative analysis of instantaneous gases productions, composition of liquid phase products and carbon deposition, we can infer the reaction mechanism of acetic acid catalytic reforming and carbon deposition process. It is found that dehydrogenation reaction, water-gas shift reaction and methane (CH_x) reforming reaction are the main source of H₂, while [CH_x] catalytic cracking reaction and CO disproportionation reaction lead to carbon deposition, furthermore carbon-steam gasification reaction can consume carbon deposition to a certain extent. Acetone is an important intermediate for carbon deposition, leading to rapid deactivation of the catalyst. By characterizing the catalyst after the reforming reaction, we consider that the formation of carbon deposition mainly includes two stages: the coating of active sites and the growth of fibrous carbon deposition. The carbon deposition on the surface of used-catalyst is 0.86%, which is mainly composed of the accumulated [CC] and [CC] bonds.     

中国农村户用沼气生产及其影响因素分析

对我国农村沼气生产情况进行了分析,认为我国农村沼气生产在取得较快发展的同时,存在较大的地区差异.文中采用面板数据对农村沼气生产影响因素进行分析,指出我国农村沼气生产明显受到该地区大牲畜存栏数量、平均温度、农户收入水平以及制度和技术进步因素的影响,而农户人均受教育程度和沼气的替代能源价格等因素对沼气生产的影响并不明显.