Syngas production from South African coal sources using Sasol–Lurgi gasifiers

Sasol has been operating the Sasol–Lurgi fixed bed coal gasification process for more than fifty years, and with ninety seven units in operation still remains the world's largest commercial application of this technology. The combined operational and engineering expertise vested in Sasol represents a formidable capability in the field of coal and gasification science. Coal is a crucial feedstock for South Africa's unique synfuels and petrochemicals industry, and is used by Sasol as a feedstock to produce synthesis gas (CO and H₂) via the Sasol–Lurgi fixed bed dry bottom gasification process.South Africa, as well as many other countries in the world, will for many years to come rely on its abundant coal resources for energy and specifically for the production of petrochemical products. Synthesis gas production through gasification is growing at a rate of approximately 10% per annum [Office of Fossil Energy, National Energy Technology Laboratory and the Gasification Technologies Council, 2000. Gasification: Worldwide use and acceptance. Contract DE-AMO1-98FE65271], indicating that gasification is definitely not a dying technology. The Sasol plants located in Secunda and Sasolburg (South Africa) gasify > 30 million tons per annum of bituminous coal to synthesis gas, which is converted to fuels and chemicals via the Fischer–Tropsch process. The production of chemicals is currently the dominant application for synthesis gas, followed by power generation, Fischer–Tropsch synthesis and gaseous fuels.Sasol–Lurgi gasifiers are extremely robust devices, and coal from sources with widely varying properties (e.g. ash content < 10% to as high as 35% or “brown coal” with moisture content of approximately 30%) can be gasified provided that certain operational changes are implemented. Other properties, like high caking propensity for example, require blending to acceptable levels and /or mechanical modifications. Interpretation of coal characterization data gives an indication of expected gasifier performance and the suitability of a specific coal source for Sasol–Lurgi Fixed Bed Gasification process. It is therefore critically important to gain an accurate and fundamental understanding of the properties and expected behavior of the targeted coal feedstock in order to (1) prepare a suitable conceptual flow scheme and (2) to maximize the eventual probability of success in any proposed gasification venture and (3) to optimize the operation and profitability of existing plants and (4) effectively address the environmental aspects.It is the view of the authors that fixed bed gasification technology has a bright future in the areas mentioned above and that Sasol has a unique role in the future application and commercialization of gasification technology globally. The unique skills of Sasol could however be complementary to those of other parties who share our view on the future of gasification and related technologies.     

Study on the suitability of New Zealand coals for hydrogen production

Internationally there is considerable interest in utilizing hydrogen as an energy carrier. The use of hydrogen offers considerable potential benefits such as reducing greenhouse emissions, reducing urban pollution, increased energy security and increased efficiencies from the use of advanced energy conversion technologies.One of the most important questions when considering the development of a hydrogen economy is “where will the hydrogen come from?” Possible answers include electrolysis of water, steam reforming of methane and the gasification of coal. Given the high costs associated with electrolysis of water, and the increase in the cost of methane predicted over time, the gasification of coal is viewed by many as being the cheapest method of hydrogen production in the foreseeable future. These considerations are particularly relevant to New Zealand where gas supplies are dwindling but where there is sufficient coal to last for many centuries at present utilization rates. This, along with the current high international interest in hydrogen energy, has been recognized by the New Zealand Government in the form of a six-year [2002–2008] research project “Hydrogen Energy for the Future of New Zealand”.One important coal property that, in particular, determines the suitability of a particular coal for use in a fluidised bed gasifier is its reactivity towards the gasification reaction. It was found that a high percentage of New Zealand's coal resource is particularly well-suited towards fluidised bed gasification, reacting at anywhere between 0.9 to 1.75 times the rate of Australian brown coals. It was found the New Zealand lignites contained significant levels of organically bound calcium, which was shown to be responsible for not only the high reactivity of the New Zealand lignites, but also a product gas composition with higher than expected hydrogen concentrations. These findings are discussed along with their implications for the gasifier and gas clean-up design.     

Measuring, understanding and visualising coal characteristics—innovations in coal geology for the 21st century

For the coal industry to remain competitive into the 21st century, particularly if coal prices remain low, it is incumbent upon the industry to understand their products and use this knowledge to improve the efficiency, environmental performance and safety with which their products are mined, processed and used. A full understanding of coal characterisation empowers the user to achieve these goals. Areas where coal characterisation is of crucial importance include integrated gasification and combined cycle (IGCC) combustion, metallurgical uses, gasification, extraction of coal bed methane and liquefaction. Future coal characterisation research avenues are reviewed. For this understanding to be achieved, radical new analytical methods that are cost effective, avoid subjective judgement, can provide prompt online measurements and are meaningful in terms of performance prediction will be required. Examples of emerging technologies are presented. Visualisation of coal quality data and the coal chain has always been important to the coal mining community. Methods of building and maintaining databases, and simulating such data are reviewed.     

煤炭地下气化中的地质问题

煤炭地下气化(UCG)产业化有助于煤炭能源结构转型发展,提高煤炭资源的低碳化利用水平,是一项符合可持续发展战略的环境友好型能源开发技术。20世纪80—90年代的国际能源危机,促使美国大力发展UCG技术,先后开展了6大系列UCG先导试验,极大推进了UCG技术进步,为全球现代UCG技术的形成提供了关键基础。系统收集整理美国40余年的UCG先导试验成果,梳理关键技术发展路径,目的是为我国正在推进的UCG技术产业化进程提供启示和借鉴。研究表明,美国通过UCG先导试验和技术探索,确定了适宜于UCG技术的煤层和煤质条件,创新发展了钻井式UCG方法和工艺,尤其是发明了可控后退式注入点(CRIP)和双水平井(P-CRIP)技术,提供了气化通道建造、气化过程控制、合成气质量提高三方面技术难题的解决方案;提出了相邻孔腔相互融合的技术思路,为从单炉开始扩大UCG气化规模奠定了可行基础。在政府层面上组织实施系统的协同科技研发计划,是美国UCG技术创新能力持续释放的关键。同时,美国UCG系列试验尚有诸多技术难题有待进一步解决,如UCG炉地质密封性及其动态监测评价、气化通道动态监控与稳定性、煤层充分气化保障技术、炉宽安全有效扩展技术、UCG炉环境监测与控制、与碳减排密切结合的UCG技术等,为我国UCG技术发展提供了需要关注的重点方向。

     

宁东煤田侏罗纪煤岩煤质特征及清洁高效利用

宁东煤田侏罗纪煤炭资源量巨大,是当前宁夏回族自治区煤炭资源开发利用的主体。为保障煤炭资源的清洁高效利用,以煤田大量勘查资料为主要依据,分析了宁东煤田侏罗纪煤的煤岩、煤质特征。结果显示：宁东煤田侏罗纪煤具有特低-低灰、特低-低硫、低磷、低砷、低氟、高发热量的特征,这些特征表明其为高清洁度动力用煤;同时还具有中高挥发分、较高氢碳原子比、焦油产率较低（普遍<7%）及富惰质组等特征表明不适于直接液化用或提取煤焦油。无黏结性、较低水分产率、较高的与二氧化碳反应性（950℃）、煤灰熔融温度,表明其适于气化,且以水煤浆气流床和干煤粉气流床为宜。综合认为研究区煤炭资源的清洁高效利用方式为动力用煤,气化用煤及以气化为基础的间接液化用煤。     

国内外煤炭地下气化技术现状及新奥攻关进展

介绍了国内外煤层地下气化的发展状况及最新进展,阐明了煤炭地下气化的优越性及技术发展过程中的坎坷历程,指出煤炭地下气化（UCG）是解决传统煤炭开采方法存在的一系列技术和环境问题的重要途径。介绍了新奥无井式煤炭地下气化技术攻关成果,展望了地下气化采煤的前景。     

煤层节理及其工程地质意义

煤层节理在煤层中普遍发育, 它不仅是矿井构造研究的重要内容, 同时也是极其重要的工程地质因素。煤层节理影响煤层的结构构造和物性特征, 从而影响煤层采落特征、顶板工程性质、瓦斯运移规律和煤层气储运采工程地质条件。研究掌握煤层节理几何和力学特征, 可指导井巷工程布置、采掘工艺的选择、安全措施的采用和煤层气开发方案的制定。     

特殊用煤研究进展及工作前景

基于煤炭地质转型及煤炭清洁高效利用要求的精细化勘查,梳理以往研究中稀缺煤、稀缺煤种、特殊煤、特殊煤种的含义,指出了特殊用煤是基于煤炭清洁高效利用具有特殊工业用途的煤炭资源,其主要种类有液化用煤、气化用煤、焦化用煤以及特殊高元素用煤。本次特殊用煤资源评价以煤岩煤质评价为基础,以煤炭分级分质利用为目标,归纳了特殊用煤资源评价的关键技术指标、经济指标及评价参数,初步提出了基于煤岩煤质特征、资源分布、产业布局的特殊高元素用煤–焦化用煤–液化用煤–气化用煤的特殊用煤评价原则及评价方法,并对晋陕蒙3省的煤炭资源进行了分级评价,统计了75个国家规划矿区液化、气化和焦化特殊用煤保有资源/储量。认为新形势下特殊用煤的研究方向是修改完善煤炭地质勘查规范、制定煤炭利用的分质分级评价标准,按照煤炭利用工艺要求实现煤质和资源的动态评价。     

江苏煤层气资源分析

简要地归纳了江苏省煤层气的成矿地质环境，分析了成煤区地质构造特征、煤层及围岩储层的物性特征，在此基础上，对主要地区煤层气资源进行了估算。     

成煤大地构造学研究

将大地构造学和煤地质学相结合,提出了一门新的边缘学科－成煤大地构造学。首先对它的定义,范围,方法,手段和特色作了详细阐述,把全球构造聚煤区分为域,带,盆三级。然后以中国为例,对成煤大地构造问题进行了讨论,主要是聚煤盆地和含煤建造分类,古构造对聚煤作用的制约和成煤大地构造与聚煤盆地的时空演化,海域构造聚煤带,深部构造对中,新生代煤盆地的控制作用,成煤构造地球化学,与成煤构造环境有关若干问题如灾变论,     

Hydrogen from coal gasification: An economical pathway to a sustainable energy future

Although hydrogen is the most abundant element in the universe, it does not occur naturally in large quantities or high concentrations on Earth. Hydrogen must be produced from other compounds such as fossil fuels, biomass, or water and is therefore considered an energy carrier like electricity. Gasification of carbonaceous, hydrogen-containing fuels is an effective method of thermal hydrogen production and is considered to be a key technology in the transition to a hydrogen economy. However, for gasification to play a major role during the transition period, capital and operating cost must be reduced and reliability and performance must be improved.Analyses show that hydrogen produced from coal-based gasification can be competitive with production from natural gas provided the cost of natural gas remains above $4/10⁶ Btu and the high reliability of gasification-based processes can be demonstrated. But for coal to be considered in a carbon-constrained environment, the cost of natural gas would have to be greater than $5.50/10⁶ Btu. The development of advanced technologies, however, offers the potential for significant reductions in capital costs, improved thermal efficiencies, and increased reliability. If these advanced technologies are capable of achieving their goals, the cost of producing hydrogen from coal could be reduced by 25–50%, even with the capture and sequestration of CO₂. With these reductions, the cost of natural gas would have to be less than $2.50/10⁶ Btu to compete, a scenario that is very unlikely to occur in the future. This potential cost reduction provides considerable impetus for continuing research and development in the production of hydrogen from coal.     

贵州盘县煤炭矿区煤（层）的物性及煤质特征研究

综合利用矿产资源现状调查工作成果,全面揭示盘县煤炭矿区已知煤（层）固有的物理化学特征,旨在总结煤炭资源的地质分布规律.区内含煤地层主要为二叠系龙潭组,煤的种类齐全,不同品质煤的分布较规律,煤炭矿区以低硫中挥发分为主,是主要的炼焦用煤和动力用煤,丰富的煤藏助力贵州经济发展.     

Advance in geochemical research on Au in coal ash北大核心CSCD

Recent researches on Au in coal ash were summarized in this paper, including the distribution law and the migration rule of gold in coal ash, as well as the influencing factors on volatility and use feasibility of Au in the progress of coal combustion. Au content in coal ash is much higher than that in the raw coal in most cases worldwide, only a small number of opposite cases are found in certain places. Occurrence of Au in coal, geological-geochemical environment of coal-forming and combustion conditions are the main factors controlling the volatility of gold in coal combustion, while the occurrence of Au in coal dominates the redistribution of Au. Through preliminary calculation, gold in coal ash is expected to have a considerable utilization potential in the southwestern Guizhou Province.     

平顶山矿区影响煤层气含气量的地质因素研究

通过对研究区煤层气含气量的研究,揭示了影响研究区煤层气含气量的地质因素。沉积因素对煤层气有重要影响：煤层厚度与含气量之间的正相关关系;构造因素对含气量具有控制作用;水文地质因素有利于煤层气的保存。     

关于煤层甲烷资源量分级的思考

通过对淮南煤田西部煤层甲烷资料的分析, 选择了煤炭储量的类别、煤层甲烷含量的有效测点密度和评价验证钻孔中参数的获取情况作为煤层甲烷资源量分级的综合指标, 建立了包括实证、控制、概略、远景和潜在等五个级别的煤层甲烷资源量的分级标准。     

江苏南部地区煤层气资源

根据江苏南部地区二叠系龙潭组煤系的分布和规模、煤矿瓦斯涌出特征、煤的产气能力、煤层的储集条件等煤层气地质条件综合研究工作，认为该区煤层气资源存在一定的勘探开发前景，对各典型含煤区块煤层气综合评价出有远景区（A类）、较有远景区（B类）和远景差区（C类）。     

An overview of the Permian (Karoo) coal deposits of southern Africa

The coal deposits of southern Africa (Botswana, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe) are reviewed. The coal seams formed during two periods, the Early Permian (Artinskian–Kungurian) and the Late Permian (Ufimian–Kazanian). The coals are associated with non-marine terrestrial clastic sedimentary sequences, most commonly mudrock and sandstones, assigned to the Karoo Supergroup. The Early Permian coals are most commonly sandstone-hosted while the younger coals typically occur interbedded with mudstones. The sediments were deposited in varying tectono-sedimentary basins such as foreland, intracratonic rifts and intercratonic grabens and half-grabens. The depositional environments that produced the coal-bearing successions were primarily deltaic and fluvial, with some minor shoreline and lacustrine settings. Coals vary in rank from high-volatile bituminous to anthracite and characteristically have a relatively high inertinite component, and medium- to high-ash content. In countries where coal is mined, it is used for power generation, coking coal, synfuel generation, gasification and for (local) domestic household consumption.     

保和堂矿区龙潭组下三角洲平原聚煤特征

邵东保和堂矿区龙潭组１，２煤形成地下三角洲平原废弃期，３煤形成于三角洲建设期，前者聚煤条件较好。在三角洲废弃破坏期，潮汐水流对形成于三角洲平原的煤层有较强的发行作用。本文提出了潮汐对煤厚，煤质及煤岩组成的作用机制。     

双碳背景下煤炭安全区间与绿色低碳技术路径

相对于地面煤化工装置,煤炭地下气化(UCG)炉体为地质体,地质条件准确认识是推进UCG气化成功的关键前提。为了最大限度避免煤炭地下气化选区选址地质风险,以贵州复杂地质条件为例,系统探讨其煤炭地下气化的敏感性地质因素。通过收集梳理贵州煤炭资源勘查资料,建立归一化的参数分级赋值、参数权重向量算法、参数权重积算法等数学模型,准确获取研究区地质参数量化数据;基于由26个地质因素构成的地质参数集,采用数理统计方法,识别地质风险关键因素对复杂构造区煤层UCG可行性的交叉影响,查明建炉可行性、过程易控性、气化安全性、开发经济性“四性”指标敏感性地质风险源。结果表明：“四性”指标地质参数的敏感性有所差异,建炉可行性、过程易控性、气化安全性、开发经济性的地质因素敏感性依次变弱,UCG可行性对建炉可行性的依赖性最强,过程易控性次之,其他两个条件离散性相对较大,敏感性明显降低;就敏感性程度而言,26项地质参数中最为敏感的是煤的坚固性系数,其他8个主控地质因素分别是煤层厚度、煤层倾角、煤厚变异系数、夹矸厚度系数、断层指数、煤层埋深、奥亚膨胀度和黏结指数,影响建炉可行性、过程易控性两个方面。就贵州UCG敏感性地质因素来说,UCG项目成功与否的关键在于建炉可行性,气化炉选址应优先考虑构造发育特征及其对煤层条件的影响;为持续推进煤炭地下气化产业发展,下一步或可立足于我国煤炭资源特性及赋存条件实际,以“四性”认识为基础建立统一的UCG地质风险评价准则,进而为典型地质条件先导性试验区选址提供科学依据。

     

矿井瓦斯涌出量影响因素分析

矿井瓦斯涌出量是受多因素综合影响的参数.地质构造、煤化作用、煤层厚度变化以及煤体结构均影响着瓦斯的涌出.矿井地质构造是控制瓦斯涌出的主导地质因素.其主要类型、规模、性质、疏密程度、排列组合以及构造部位等差异,对瓦斯涌出有不同程度的影响.在煤化作用过程中,瓦斯小断产生,而煤层瓦斯的伴生量直接依赖于煤化变质程度,故变质程度越高,产生的瓦斯量就越多.