积极推进煤炭地下气化技术的试验研究和示范应用

本文简要介绍了国内外煤炭地下气化的发展概况。与传统的煤炭地下开采相比,煤炭地下气化技术具有安全、高效、污染少等优点,是我国开展节能减排、调整能源结构和发展绿色经济的重要途径。积极推进煤炭地下气化技术研究和示范应用具有战略意义。提出我国煤炭地下气化技术需要尽快由目前的工业化试验阶段转入示范应用阶段。本文总结了影响我国煤炭地下气化技术发展的3个方面的主要问题,提出了积极推进煤炭地下气化技术的试验研究和示范应用的6项建议。     

利用煤炭地下气化技术生产合成氨的构想

介绍煤炭地下气化技术的最新进展,提出利用煤炭地下气化产生的水煤气作为生产合成氨的原料的构想。     

浅层地震勘探在地下采空区探测中的应用

随着现代科技进步和发展,地震勘探技术逐渐成为现代煤炭开采地质调查中的重要方法。地震勘探技术在地下采空区探测中也得到了广泛应用,并取得良好效果,为中国采空区探测发展奠定基础。针对浅层地震勘探技术在中国煤炭采空区探测中的应用进行分析,保障采空探测技术可持续发展。     

中国煤炭地下气化的近期研究与发展

为了进一步提高煤炭地下气化中的煤气热值和产量,在总结国内外地下气化工艺的基础上,提出了长通道、大断面、两阶段煤炭地下气化新工艺和分离控制注气点富氧-水蒸气煤炭地下气化新工艺以及提出了煤炭地下催化气化新工艺的构想.在理论研究、模型试验的基础上,进行了半工业性试验、工业性试验和工业性应用.新奥集团与中国矿业大学合作正在内蒙古乌兰察布市选点进行我国首次无井式煤炭地下气化试验.经过20多年的研究,UCG技术日臻成熟,目前用于矿井中"遗弃"煤炭资源的回收和浅部资源的开发,在技术上是可行的.     

烟道气中的二氧化碳可制取生物油

日前从内蒙古自治区乌兰察布政府了解到，内蒙古新奥煤炭地下气化项目日前成功实现了煤炭地下气化燃烧发电。目前该项目装置已平稳运行300多天，累计气化燃烧发电46．9万千瓦时。按照规划，到2012年前，利用地下煤炭气化技术还将建成年产2万吨优质甲醇生产线。     

洁净煤技术开发与应用

本文通过分析国内外煤层气开发和煤炭地下气化现状及发展前景，提出了我省开发煤层气和发展煤炭地下气化事业的建设。     

积极推进煤炭地下气化技术的示范应用

<正>煤炭地下气化(Underground Coal Gasification,以下简称UCG)是煤炭气化的一种创新技术,它是将处于地下的煤炭直接进行有控制的燃烧,通过对煤的热作用及化学作用而产生可燃气体的技术。与传统的煤炭地下开采相比,UCG具有安全、高效、污染少等优点。     

协庄煤矿煤炭地下气化取代无烟煤造气

[本刊讯]山东新汶矿业集团协庄煤矿利用煤炭地下气化技术取代无烟煤造气,取得良好经济效益,一年可为企业节约资金300余万元。煤炭地下气化是在地下将高分子煤用高温转变为低分子燃气,并输送到地面的一种综合性能源生产新技术。其实质是从煤炭中直接提取含能的部分,将矸石等附属物留在地下,从而达到避免环境污染,提高煤炭资源的利用率,实现安全生产的目的。该技术的另一个特点是可以回收被传统采煤工艺所遗弃的煤炭资源(煤柱、薄煤层、极倾斜煤层),开发城市、江河、交通线以下的煤炭资源。协庄煤矿煤炭地下气化技术工程于2000年下半年起步,今…     

气化采煤

气化采煤也就是煤炭地下气化技术。煤炭地下气化是将处于地下的煤炭进行有控制地燃烧,通过对煤的热作用及化学作用产生可燃气体,集建井、采煤、气化工艺为一体的多学科开发洁净能源与化工原料的新技术,其实质是只提取煤中含能组分,变物理采煤为化学采煤,因而具有安全性好、投资少、效率高、污染少等优点,     

煤炭地下催化气化新工艺

煤炭地下气化是我国洁净煤技术研究的重要领域之一,由于受各种复杂因素及工艺控制的影响,其煤气组分、热值及稳定产气率诸方面均无法与地面气化炉煤气相比较.针对这一问题,提出了煤炭地下催化气化新工艺,以钙盐作为主催化剂并运用特殊的带入装置将催化剂带入地下气化炉进行催化气化,从而提高煤气组分、热值和产气率.     

Public perceptions of underground coal gasification in the United Kingdom

There is growing interest internationally in the technology of Underground Coal Gasification (UCG) as a means of accessing the energy contained within inaccessible coal reserves. One of the potential obstacles to UCG deployment is adverse public perceptions and reactions, either stopping or delaying proposed applications. This paper explores the public perceptions of UCG in the UK through a detailed case-study and focus group discussion. A failed proposal for a UCG drill site at Silverdale (Staffordshire) provides an opportunity to understand the influence of local social, cultural and institutional factors on the manner in which the risks and benefits associated with UCG are perceived. The participants of the focus group recognised the potential of UCG as a secure source of energy for the UK in the future, provided that it is safe to humans and the environment and cost-effective. The group discussed potential benefits to the local community, potential risks, the role of carbon dioxide capture and storage, and links to the hydrogen economy. The group recommended that an open, transparent and consultative process of decision-making and operation should be adopted by the developer, operator and regulator; and that UCG should be developed at a remote site, preferably on land, before applying it in coal seams close to populated areas.     

Underground coal gasification: From fundamentals to applications

Underground coal gasification (UCG) is a promising option for the future use of un-worked coal. UCG permits coal to be gasified in situ within the coal seam, via a matrix of wells. The coal is ignited and air is injected underground to sustain a fire, which is essentially used to “mine” the coal and produce a combustible synthetic gas which can be used for industrial heating, power generation or the manufacture of hydrogen, synthetic natural gas or diesel fuel. As compared with conventional mining and surface gasification, UCG promises lower capital/operating costs and also has other advantages, such as no human labor underground. In addition, UCG has the potential to be linked with carbon capture and sequestration. The increasing demand for energy, depletion of oil, and gas resources, and threat of global climate change have lead to growing interest in UCG throughout the world. The potential for UCG to access low grade, inaccessible coal resources and convert them commercially and competitively into syngas is enormous, with potential applications in power, fuel, and chemical production. This article reviews the literature on UCG and research contributions are reported UCG with main emphasis given to the chemical and physical characteristic of feedstock, process chemistry, gasifier designs, and operating conditions. This is done to provide a general background and allow the reader to understand the influence of operating variables on UCG. Thermodynamic studies of UCG with emphasis on gasifier operation optimization based on thermodynamics, biomass gasification reaction engineering and particularly recently developed kinetic models, advantages and the technical challenges for UCG, and finally, the future prospects for UCG technology are also reviewed.     

Exergy analysis in the assessment of hydrogen production from UCG

The demand for H₂ increases rapidly with the gradual recognition of the potential of H₂ as an important secondary energy. At present, coal gasification is the main way to obtain hydrogen on a large scale and at a low cost in China. The underground coal gasification (UCG), as a kind of in-situ utilization technology that can exploit the unreachable deep coal resources, could become an alternative H₂ production pathway. This paper presents comparative study of energy utilization and resource consumption in H₂ production by UCG and typical surface coal gasification (SCG) technology, namely Lurgi fixed bed gasification, with 1.2 billion Nm³/a throughput of H₂ as example, to offer corresponding data support. The efficiency and the amount of resources consumed in constructing and operating each coal-to-hydrogen system under different conditions have been researched from exergetic point of view, which is not reported in existing literatures. In this paper, the exergy efficiency is calculated to be 40.48% and 40.98% for hydrogen production using UCG and SCG. The result indicates the competitiveness of UCG in the field of hydrogen production comparing with widely used coal gasification technology. The resource consumption is measured by cumulative exergy consumption (CExC), which is 8.17E+10 MJ and 6.57E+10 MJ for H₂ production from UCG and SCG. The result shows that although the H₂ production from UCG has higher CExC, it can significantly reduce the resource consumption of equipment comparing with H₂ production from SCG, indicating its advantage in total investment. It is found that the exergy efficiency increases with the rise in H₂O-to-O₂ and O₂-to-CO₂ ratio, while the value of CExC decreases with the appreciation of H₂O-to-O₂ ratio yet increases as the O₂-to-CO₂ ratio rises. In addition, the sensitivity analysis of production capacity reveals that the exergy efficiency gap and CExC gap between hydrogen production by UCG and SCG diminishes at smaller scale production capacities, showing that UCG is more suitable for small-scale hydrogen production.     

Underground coal gasification: A new clean coal utilization technique for India

Energy demand of India is continuously increasing. Coal is the major fossil fuel in India and continues to play a pivotal role in the energy sector. India has relatively large reserves of coal (253 billion tonnes) compared to crude oil (728 million tonnes) and natural gas (686 billion cubic meters). Coal meets about 60% of the commercial energy needs and about 70% of the electricity produced in India comes from coal, and therefore there is a need for technologies for utilization of coals efficiently and cleanly. UCG offers many advantages over the conventional mining and gasification process. UCG is a well proven technology. Due to the site-specific nature of the process, possibility of land subsidence and surrounding aquifer water contamination, this technology is still in a developing stage in India. Potential for UCG in India is studied by comparing the properties of Indian coals with the properties of coal that are utilized by various UCG trials. The essential issues are elaborated for starting UCG in India based on the reported information from the successful field trials conducted all over the world. Indian industries are in the process of initiating pilot studies of UCG at various sites. This study will help to motivate both applied and theoretical research work on UCG sites in India and after detailed analysis it will provide basic data to interested industries.     

Integration of underground coal gasification with a solid oxide fuel cell system for clean coal utilization

Underground coal gasification (UCG) is a promising clean coal technology. Typically, the syngas obtained from UCG is used for power generation via the steam turbine route. In the present paper, we consider UCG as a hydrogen generator and investigate the possibility of coupling it with a solid oxide fuel cell (SOFC) to generate electrical power directly. We show, through analysis, that integration with SOFC gives two specific advantages. Firstly, because of the high operating temperature of the SOFC, its anode exhaust can be used to produce steam required for the operation of UCG as well as for the reforming of the syngas for the SOFC. Secondly, the SOFC serves as a selective absorber of oxygen from air which paves the way for an efficient system of a carbon-neutral electrical power generation from underground coal. Thermodynamic analysis of the integrated system shows considerable improvement in the net thermal efficiency over that of a conventional combined cycle plant.     

Theory of reverse combustion linking

The present work suggests a theory of reverse combustion linking (RCL). RCL is a central unit operation of underground coal gasification (UCG) technology. The theory is based on analyzing the stability of different branches of the propagation speed curves and determining the regime that is responsible for propagation of the flame during RCL. The theory is in good qualitative and quantitative agreement with the data obtained in practical use of RCL in UCG operations.     

Production of power using underground coal gasification

Underground coal gasification (UCG) is a process that converts deep, un-mineable coal resources into syngas, which can then be converted into valuable end products such as electric power. This paper provides a summary of the options to combine UCG with electric power production and focuses on commercial-scale applications using a combined-cycle power plant including integration options and syngas cleanup steps. Simulation results for a UCG power plant with carbon capture are compared against the results for an equivalent Integrated Gasification Combined Cycle (IGCC) plant using the same feedstock. Relative capital cost savings for a UCG power plant are estimated based on published IGCC process unit costs. The UCG power plant with carbon capture is shown to provide a higher thermal efficiency, lower CO₂ intensity, and lower capital cost than an equivalent IGCC plant. Finally, the potential of UCG as a method for producing cost-effective, low-emissions electrical power from deep coal is discussed and some of the challenges and opportunities are summarized.     

Overview of underground coal gasification operations at Chinchilla,Australia

Underground coal gasification (UCG) is a process which converts deep, un-mineable or difficult to mine coal resources into syngas which can then be converted into valuable end products such as electric power, liquid fuels, synthetic natural gas and chemicals. This paper provides a summary of the UCG operations conducted at the Chinchilla Demonstration Facility in Australia, focusing on gasifiers constructed using directional drilling. A number of the experiences and key lessons learned from operating multiple underground gasifiers over several years at the facility are described. Implications for the implementation in commercial projects using UCG are also discussed. Finally, the potential of UCG as a method for producing syngas from deep coal is discussed and some of the challenges and opportunities are summarized.     

Thermal–mechanical modelling around the cavities of underground coal gasification

Underground coal gasification (UCG) is an efficient method for the conversion of the deep coal resources into energy. This paper is concerned with a feasibility study of the potential of deeply lying coal seams (>1200 m) for the application of UCG combined with subsequent storage of CO₂ for a site located in Bulgaria. A thermal–mechanical coupled model was developed using the ABAQUS software package to predict the heat transfer, the stress distributions around the UCG and the consequent surface subsidence. Material properties of rocks and coal were obtained from existing literature and geomechanical tests which were carried out on samples derived from the demonstration site in Bulgaria. Three days of gasification has been simulated by assigning a moving heat flux on a cell of 2 m × 2 m × 2 m at a velocity of 2 m/day. Results of temperature and stress distribution showed that the developed numerical model was able to simulate the heat propagation and the stress distribution around cavities under a thermal–mechanical coupled loading during the UCG process. Also, the surface subsidence was found to be 0.08 mm after three days of gasification for the case studied. It is anticipated that the results of this paper can be used for the prediction and optimization of the UCG process in deep coal seams.