预混天然气在多孔介质燃烧器中的燃烧与传热

在一台小型渐变型多孔介质燃烧器上进行了预混天然气燃烧与传热试验研究,探讨了天然气速度和多孔介质厚度对多孔介质燃烧室的温度分布、排烟温度和流动阻力的影响。结果表明,天然气在渐变型多孔介质燃烧器中燃烧稳定,燃烧室与水冷夹套间的换热受天然气速度和多孔介质厚度影响,换热效果比空管中燃烧明显增强,同时预混天然气通过多孔介质的进出口压差随着天然气速度和多孔介质厚度的增加而增加。     

合成天然气水合物实验研究

天然气水合物(NGH)是天然气与水在低温高压条件下形成的笼形物,亦称可燃冰.在冻土带和海洋中已发现大量天然气水合物,是清洁燃料的后续天然资源,但开采技术尚不成熟.由于1m~3天然气水合物在常温下可释放约164m~3的天然气和0.8m~3的水,因此合成天然气水合物,可实现天然气的固态运输,更便于在天然气汽车上的储存.本文介绍天然气水合物的基本性质及其人工合成研究取得的进展.     

天然气水合物合成与分解模拟实验研究与设计

针对大学化学中有关天然气水合物的内容,设计了天然气水合物的教学实验和模拟实验装置,实现了天然气水合物在不同实验条件下的合成与分解等多个实验。仪器操作简单,实验可重复性高,可通过多种方式判断水合物是否生成或分解。     

建立天然气检测实验室的技术方案

提出建立天然气检测实验室的技术方案,提供天然气质量评判基础数据。分析商品天然气、页岩气、液化天然气、压缩天然气及煤层气等5类天然气产品的主要技术指标,确定天然气检测的14种技术。综合考虑"人、机、料、法、环"几个方面,建立技术全面、管理科学、过程可控、质量可靠的天然气检测实验室,保证天然气质量检测结果准确、公正、可信。     

提高碘量法测定天然气中硫化氢效率的方法

碘量法是测定管道输送天然气中硫化氢的一种经典方法,而管道输送天然气中硫化氢含量较低,按照GB/T11060.1–2010方法测定,取样量较大,取样时间长,影响工作效率。针对此问题,从两方面对碘量法进行改进:减小天然气取样量进行试验,并与国标规定取样量时的实验结果进行比对,确定最佳取样量;增大取样流量进行试验,并与国标规定取样流量时的实验结果进行比对,确定最佳取样流量。对硫化氢质量浓度为7.2~14.3,14.3~28.7 mg/m~3的天然气样品进行试验测定,结果表明,将天然气取样量减少为20 L,取样时间分别由200,100 min缩短为40 min;将天然气取样流量设定为750 m L/min,取样时间分别由200,100 min缩短为133,67 min。减少取样量或者提高取样流量,均能缩短管输天然气的取样时间,提高检测效率。     

基于量子化学计算方法的天然气水合物稳定性研究进展

天然气水合物以资源丰富、优质、洁净等特点,被视为21世纪新能源。天然气水合物稳定性的研究对天然气水合物资源勘探开发具有重要意义。本文简述了微观、介观、宏观、矿藏四个尺度天然气水合物稳定性的研究,重点从微观量子尺度介绍了量子化学计算方法对水合物晶体结构及其稳定性以及水合物宏观物理特性微观表征的计算研究。应用量子化学计算方法可以对天然气水合物的晶体结构、电子轨道分布、振动光谱、成键特性及主客体相互作用进行计算研究,其结果能够为天然气水合物在油气储运、水合物成藏、开采及其综合利用等方面的研究提供理论支持。目前,量子化学计算方法的优化与分子动力学模拟、分子力学模拟等方法的结合将有助于水合物形成和分解微观机理研究的发展,提升计算精度和扩大研究体系,为矿场尺度的天然气水合物资源开采利用提供理论支持。     

天然气水合物浆体分解对其在垂直管中流动特性影响的研究

针对天然气水合物浆体开采提升过程中水合物分解的问题,采用Euler多相流模型以及Finite-Rate/Eddy-Dissipation模型对天然气水合物浆体垂直管输的固-液两相流动以及气-液-固三相流流动特性进行研究。结果表明,受天然气水合物分解产生的气体影响,天然气水合物颗粒的速度分布、体积浓度分布均随高度的变化呈现出波动-均匀-波动的规律;水合物分解对浆体管道运输具有减阻作用,并提出天然气水合物浆体分解工况下,其流动速度不应低于3m·s~(-1);通过对管道的阻力特性分析,拟合出水合物分解下的水力提升阻力损失与流速的关系式,为天然气水合物浆体管道的经济提升参数提供指导。     

天然气水合物研究进展

本文介绍了天然气水合物研究的历史和现状, 天然气水合物的结构, 它在冻土地带和海洋底部地表层的形成过程, 它对石油天然气工业的影响以及抑制生成天然气水合物的方法。介绍了天然气水合物作为潜在能源的巨大优势以及它对地球气候变化--温室效应的潜在危险性。     

“一带一路”国家战略催生仪器仪表新机遇

正"一带一路"加速了国际市场的布局,仪器仪表等制造业作为国民经济的基础,也将面临新的机遇与挑战。石油、天然气等能源行业一直是"一带一路"建设重要支点。位于"丝绸之路经济带"上的中亚各国油气储量丰富,历来是海外能源合作的重点地区。目前,我国已开展土库曼斯坦阿姆河天然气田勘探开发与生产运营、中亚天然气管道建设运营以及相应的天然气进口与贸易等业务。在石油、天然气等能源的开发、运输过程中,各种测量的液位仪表和仪表等一系列的装备设施具有十分重要的作用,     

天然气密度计算结果的不确定度分析比较

天然气的密度通常采用气相色谱分析方法得到。分析了这种方法计算密度结果的不确定度,并与SY/T6143《天然气流量的标准孔板计量方法》中经验公式计算的密度不确定度进行比较。结果表明:按照SY/T 6143标准计算的密度不确定度与天然气压力和温度有关,而采用气相色谱分析方法计算的密度结果的不确定度仅与天然气组分含量有关;SY/T 6143标准所计算的密度不确定度结果更可靠些。     

The role of natural gas as a primary fuel in the near future, including comparisons of acquisition, transmission and waste handling costs of as with competitive alternatives

Natural gas comprises about a quarter of the United States' energy use. It is more environmentally friendly than oil and coal due to lower carbon dioxide (CO2) emissions per unit, less costly per unit of energy and more readily available domestically in abundant supply. However, due to a number of barriers in the political, infrastructural, pricing and other arenas, the use of natural gas as a significant energy source in the United States has been limited. In our paper, we highlight the favorable qualities of natural gas and its benefits for the consumer, producer, and environment, having compared the costs of the various components of the natural gas business such as drilling and transport to that of coal and oil. Moreover, we touch upon the major issues that have prevented a more prevalent use of the gas, such as the fact that the infrastructure of natural gas is more costly since it is transported though pipelines whereas other energy sources such as oil and coal have flexible systems that use trains, trucks and ships. In addition, the powerful lobbies of the coal and oil businesses, along with the inertia in the congress to pass a national climate change bill further dampens incentives for these industries to invest in natural gas, despite its various attractive qualities. We also include discussions of policy proposals to incentive greater use of natural gas in the future.     

A New Model for the Genesis of Natural Gases——Multi-source Overlap, Multi-stage Continuity, TypeControlled by Main Source and Nomenclature by Main Stage (Ⅱ)——Multi-stage Continuity and Nomenclature by Main Stage

The generation of natural gases involves several stages and the various stages are of continuous transition. This is another feature of natural gas generation. The term "multi-stage" is relative mainly to oil-generating threshold value and liquid window. The evolution of organic matter is affected by different epigene agencies and natural gases differing in geochemical properties such as biogenic gas (bacterial gas), thermocatalytic gas and pyrolytic gas could be produced at different stages of the evolution of organic matter. The proposal of bio-thermocatalytic transitional-zone gas presents a pattern of mutual linking and continuous transition of natural gases originated at different stages.In the genetic classification of natural gases, the nomenclature of a certain gas is based mainly on the epigene agency which is responsible for its formation, for example, biogenic gas, pyrolytic gas. That is the "nomenclature by the main stage" described in this study. On account of the continuity of gas generati     

Natural gas storage cycles: Influence of nonisothermal effects and heavy alkanes

A mathematical model is developed for examining the influence of nonisothermal effects and accumulation of heavy alkanes on natural gas storage cycles. The model is solved for the charge and discharge steps of the cycle. This is the first study to solve the natural gas storage problem for a nonisothermal charge of natural gas containing impurities. We examine both adiabatic and isothermal operation of natural gas and pure methane storage cycles on BPL carbon and an activated carbon prepared from coconut shells. Our simulations show for both carbons that the adiabatic gas storage cycles operate under subcooled conditions with respect to the feed temperature due to long discharge times and the desorption heat. It is also shown that degradation of gas storage performance due to impurities depends more on selectivity of the material for heavy alkanes than on adsorption capacities.     

Metrological issues in energy measurement on biogas

The use of biogas as regenerative energy can be achieved more efficiently by injecting the treated biogas into natural gas grids since the localisation of the biogas CHP (combined heat and power) plant is made independent from the site of the biogas production. Thus, the utilisation of the heat generated in the CHP plant may be optimised. For that reason, the National and European regulations support injection into the natural gas grid. This paper deals with the general metrological issues concerning injection from the specific aspects of measurement technology. The issues discussed include the adjustment of biogas to the characteristics of natural gas (treatment to produce biomethane) and the measurement of biomethane calorific value. Measuring the calorific value of natural gas today is almost always based on the use of process gas chromatographs specifically designed for the analysis of typical natural gases. Natural gas chromatographs are only suitable under minted conditions for use with biomethane due to differences in the composition of natural gas and biomethane. This paper explains the specific issues and solutions for the measurement of the calorific value of biomethane and their implementation in current plants equipped with injection facilities.     

Conventional processes and membrane technology for carbon dioxide removal from natural gas:A review

Membrane technology is becoming more important for CO 2 separation from natural gas in the new era due to its process simplicity,relative ease of operation and control,compact,and easy to scale up as compared with conventional processes.Conventional processes such as absorption and adsorption for CO 2 separation from natural gas are generally more energy demanding and costly for both operation and maintenance.Polymeric membranes are the current commercial membranes used for CO 2 separation from natural gas.However,polymeric membranes possess drawbacks such as low permeability and selectivity,plasticization at high temperatures,as well as insufficient thermal and chemical stability.The shortcomings of commercial polymeric membranes have motivated researchers to opt for other alternatives,especially inorganic membranes due to their higher thermal stability,good chemical resistance to solvents,high mechanical strength and long lifetime.Surface modifications can be utilized in inorganic membranes to further enhance the selectivity,permeability or catalytic activities of the membrane.This paper is to provide a comprehensive review on gas separation,comparing membrane technology with other conventional methods of recovering CO 2 from natural gas,challenges of current commercial polymeric membranes and inorganic membranes for CO 2 removal and membrane surface modification for improved selectivity.     

Determination of sulfur components in natural gas: A review

More stringent environmental regulations as well as higher demands presently being imposed on the sulfur content of natural gas feed-stocks for chemical processes necessitate the development of new analytical procedures for sulfur determination in natural gas. Only analytical procedures based on gas chromatography can meet the sensitivity and accuracy requirements dictated by environmental regulation institutions and modern chemical industry. The complexity of the natural gas matrix as well as the extremely low concentration levels at which the sulfur species occur make the development of these analytical methods a true challenge. In this review the three steps common for analytical methods for trace analysis in complex matrices, i.e. pretreatment, chromatographic separation, and detection, are discussed in detail. Possible methods for calibration of the system are discussed in the final section. Various techniques to determine sulfur in natural gas are described. Depending on the application, the most suitable system has to be selected. For example, for on-line application in a hazardous area a simple and rugged system is required, i.e. a simple gas chromatograph with a flame photometric detector, while for laboratory application a more complex instrument including preconcentration, column switching, and more exotic detection systems could be more suitable. Therefore it is crucial to define the requirements of the instrument at an early stage and use the information in this review article to develop/select a dedicated instrument/procedure for the problem at hand.     

天然气与硫酸盐热化学还原反应的模拟实验研究

为探讨天然气中高含量硫化氢形成的化学机制，利用高温高压反应装置，对天然气与固态硫酸钙反应体系进行了热模拟实验研究。使用气相色谱仪、微库仑仪、傅里叶变换红外光谱仪和X射线衍射仪对产物进行了分析，探讨了硫酸盐热化学还原反应的热力学特征，并进行了反应动力学研究。结果表明，高温下天然气与固态硫酸钙可以发生反应，产物主要为硫化氢、二氧化碳、碳酸钙、水和炭。热力学研究表明，天然气与固态硫酸钙的反应可行，升高温度对反应有利，同一温度下长链烷烃与固态硫酸钙发生反应的可能性要比短链烷烃大。根据动力学模型得到反应活化能为96.824kJ/mol。     

Tuning methane content in gas hydrates via thermodynamic modeling and molecular dynamics simulation

Storage and transportation of natural gas as gas hydrate (“gas-to-solids technology”) is a promising alternative to the established liquefied natural gas (LNG) or compressed natural gas (CNG) technologies. Gas hydrates offer a relatively high gas storage capacity and mild temperature and pressure conditions for formation. Simulations based on the van der Waals–Platteeuw model and molecular dynamics (MD) are employed in this study to relate the methane gas content/occupancy in different hydrate systems with the hydrate stability conditions including temperature, pressure, and secondary clathrate stabilizing guests. Methane is chosen as a model system for natural gas. It was found that the addition of about 1% propane suffices to increase the structure II (sII) methane hydrate stability without excessively compromising methane storage capacity in hydrate. When tetrahydrofuran (THF) is used as the stabilizing agent in sII hydrate at concentration between 1% and 3%, a reasonably high methane content in hydrate can be maintained (∼85–100, v/v) without dealing with pressures more than 5 MPa and close to room temperature.     

Forecasting China’s natural gas consumption based on a combination model

Ensuring a sufficient energy supply is essential to a country. Natural gas constitutes a vital part in energy supply and therefore forecasting natural gas consumption reliably and accurately is an essential part of a country's energy policy. Over the years, studies have shown that a combinative model gives better projected results compared to a single model. In this study, we used Polynomial Curve and Moving Average Combination Projection (PCMACP) model to estimate the future natural gas consumption in China from 2009 to 2015. The new proposed PCMACP model shows more reliable and accurate results: its Mean Absolute Percentage Error (MAPE) is less than those of any previous models within the investigated range. According to the PCMACP model, the average annual growth rate will increase for the next 7 years and the amount of natural gas consumption will reach 171600 million cubic meters in 2015 in China.     

First-Principles Evaluation of One-Dimensional Metal-Organic Frameworks for Electrocatalytic C−H Activation of Natural Gas

To replace the oxygen evolution reaction with thermodynamically more favorable and economically more profitable methane and ethane (the major components of natural gas) electrochemical partial oxidation, we employed constant electrode potential density functional theory calculations to screen 20 one-dimensional metal-organic frameworks containing heteroatom-substituted benzene as electrocatalysts. By computing the Pourbaix diagrams, O−H binding energies, and C−H activation barriers, we determined that although none of these catalysts were able to activate methane, one was able to hydroxylate ethane to ethanol with facile kinetics, making it a promising electrocatalyst for natural gas oxidation.