Status and Suggestion for Modern Coal Chemical Industry and Coal Clean Technology

Coal is fossil fuel abundant and widespread all over the world. It is a vital resource for energy security in our country, because the supply is stable. In this paper, the important role of coal played in the total primary energy supply was described, and the status of modern coal chemical industry and clean coal technologies was analyzed. Based on the scientific research experiences of author, strategy and suggestion for Chinese development were proposed according to the regulation of scientific panning. In China, there are more social benefits and strategic meaning for developing the coal high-efficiency utilization technology. Considering of the general situation of our countries, these technologies with the features of can be industrialized, advanced, applicative, mature and feasible should be developed preferentially. The high-expend, low economic effectiveness and behindhand technologies should be abandoned. So, the development of coal clean technology in China should meet the natural resources, restrictive condition and elements of our countries industry situations. Based on these analysis, the most important technologies and fundamental researches should be prior developed in China.

Clean coal technologies in Japan： A review

Coal is the primary fossil fuel most used in the world for the electricity generation, iron making, and cement/concrete and chemical production. However, utilization of coal also results in emissions of CO_2, SO_x, NO_x and other noxious compounds. The development of clean coal technology(CCT) is a main issue to maintain a clean environment. CCT in Japan is considered the highest level in the world. In this review, the developing CCTs in Japan including high efficiency combustion technologies, advanced gasification technologies, CO_2 recovery and utilization technologies, and flue gas cleaning technologies are introduced and discussed. It is expected to provide some new view-of-points for CCT development.

Prospect of Clean Coal Technologies to be Used in Fujian Province Power Industry

This paper is based on the existing status and development prediction of Fujian power industry, and describes that the structure of energy sources for generating power which will mainly use coal, will not be changed in the 2010s and 2020s in Fujian Province. In order to meet the requirements of high efficiency and envirofimental protection, the usage of clean coal technologies for power generating will be an inevitable option and the technologies will occupy the important position in Fujian power industry. This paper puts forward the staged targets and measures of developing and utilizing clean coal technologies, suggests that all government depotments related should give support and guarantee in policies and conditions, and welcome technical and economic cooperation at home and abroad, which is good for co-development of both parties.

新型能源体系发展背景下煤炭清洁高效转化的挑战及途径

当今世界地缘政治风险加剧、气候环境问题凸显,能源转型变革加快。在此背景下,构建更加适应形势变化的能源体系对提高我国能源供应系统的可持续性及安全稳定性意义重大。目前我国化石能源仍占据主体地位。油气资源存在能源安全问题及新能源技术水平有待提升,中国短期内对煤炭能源仍将保持较高依赖性。因此,推进煤炭清洁高效转化对于新型能源体系的构建具有重要意义。首先对新型能源体系的具体内涵与构建方向展开讨论,并在此基础上,对新时代中国煤化工产业的发展现状以及面临的机遇与挑战进行了阐述,以期为煤炭的清洁高效转化技术的进步及煤化工产业的未来发展提供建议。新时代要求赋予新型能源体系更多的内涵。因此从战略上看,未来能源体系应具备“安全高效、清洁低碳、多元协同、智能普惠”多个特征,这也对煤炭产业的清洁高效发展提出了更高的要求。我国的煤炭清洁高效转化已取得显著进步,但多个关键技术仍亟待突破。结合煤炭产业转型发展与“双碳”目标关系的系统性认识,在新型能源体系建设的需求下,推进煤炭清洁高效转化对于社会经济发展、助力“双碳”目标实现具有重要意义,其关键在于加强该领域相关学科专业的基础研究和煤炭清洁高效转化技术的创新开发。

基于专利信息分析的洁净煤技术研发现状和趋势分析

洁净煤技术是实现煤炭清洁高效利用的重要途径,对于减少二氧化碳排放、实现“双碳”目标意义重大。基于Patsnap专利数据库,以全球洁净煤技术的相关专利数据为研究对象,采用TAM三维分析模型,从技术发展、专利权人构成以及市场分布3个层面对专利信息进行知识挖掘和知识计量,通过与全球各国的发展状况横向对比,分析我国目前存在的技术短板、核心技术以及洁净煤技术未来的发展趋势,并据此提出相应的对策建议。研究表明:当前洁净煤技术正处于由成长期向成熟期过渡阶段;我国洁净煤技术专利存在量优质劣、海外布局薄弱、缺乏核心竞争机构、企业研发力度不强等短板;碳减排技术与污染物控制技术是当前专利技术的焦点,未来洁净煤技术发展的重点研究方向为煤炭资源综合利用技术。企业应发挥技术研发创新的主体作用,加强碳减排技术和煤炭综合利用技术的研发,进一步关注技术研发的质量;政府未来应加大对碳减排技术以及综合利用技术示范项目建设的政策支持力度,在这两个领域做好科学布局和技术储备,加大财政税收政策支持力度,构建健全的市场激励手段,引导企业加强研发以及运用先进的洁净煤技术。

“双碳”背景下干法选煤技术研究新进展

干法选煤技术适合高寒干旱地区煤炭的分选加工,尤其对于我国来说,大的煤炭基地都位于中西部缺水地区,发展干法选煤是我国未来煤炭分选一个大的发展趋势。文章简要介绍了几种常用的干法选煤设备。然后分析了“双碳”背景下,我国干法选煤技术的新进展和新方向,包括以射线干选机、风力干选机为代表的大型干法选煤设备,专用于0~13mm细粒级煤炭干法分选技术,以及干选智能化建设领域的研究进展:射线类干法分选机通过双源识别算法的改进升级,使识别精读进一步提升;风力干选设备通过研制分选床面横向、纵向角度伺服控制系统和数字供风系统,以及建立选煤过程闭环控制数学模型和干法选煤数字孪生平台等实现智能化管理模式。最后,笔者从绿色干法分选、高效干法分选、智能干法分选三方面展望了新形势下干法选煤技术的发展方向。

管状带式输送机常见故障分析及综合治理方案

为有效解决管状带式输送机因跑偏、扭转等故障导致的设备停运、损坏、使用寿命降低等实际问题,基于故障产生的原因分析,逐步形成了以跑偏及扭转故障管控、辅助清扫措施设置、电气保护设施设计、日常检查和周期性检查维护为一体的综合治理方案。生产实践表明:经过综合治理,管状带式输送机事故率有效降低,轻微跑偏故障处理时间能有效缩短至10min以内,输送带有效使用年限延长50%。该治理方案解决了管状带式输送机常见的故障,提高了自动监测保护水平,可以有效避免事故的扩大化,降低事故处理难度,延长运输设备的使用寿命,有利于生产的稳定运行。

专业群建设视角下化工生产技术与煤的清洁利用思考

煤炭作为一种重要的化石能源,在全球能源结构中有着重要地位。然而,传统煤炭开采及利用方式不仅存在能源浪费和环境污染的问题,也无法满足日益增长的能源需求和可持续发展的要求。煤炭产业发展正朝着智能、环保、绿色、安全等方向发展。从煤炭智能开采与煤的清洁利用产业链出发,结合六盘水职业技术学院煤矿智能开采技术专业群建设的经验,思考化工生产技术在煤的清洁利用中的作用,遵循煤炭产业发展,促进专业群的动态发展,适应煤炭产业高质量发展需要。

The view of technological innovation in coal industry under the vision of carbon neutralization

This paper analyzed the current situation and development trends of energy consumption and carbon emissions,and the current situation and development trend of coal consumption in China.In the context of recently established carbon peak and carbon neutralization targets,this paper put forward the main problems associated with the green and low-carbon development and utilization of coal.Five key technological innovation directions in mining were proposed,including green coal development,intelligent and efficient mining,low-carbon utilization and conversion of coal,energy conservation and emission reduction,carbon capture,utilization and storage(CCUS).Focusing on the above technological innovation directions,it is suggested to carry out three basic theories,including the theory of green efficient intelligent mining,clean and low-carbon utilization and transformation of coal,and CCUS.Meanwhile,it is proposed to develop 12 key technologies,including green coal mining and ecological environment protection,efficient coal mining and intelligent mine construction,key technologies and equipment for efficient coal processing,underground coal gasification and mining,ultra-high parameter and ultra-supercritical power generation technology,intelligent and flexible coal-fired power generation technology,new power cycle coal-fired power generation technology,the development of coal-based special fuels,coal-based bulk and specialty chemicals,energy conservation and consumption reduction,large-scale and low-cost carbon capture,CO_(2) utilization and storage.Finally,necessary measures from the governmental perspective were also proposed.

Development of a Fuel-flexible Co-gasification Technology

As one of promising clean coal technologies used to reduce pollutant emission and CO2 discharge, cogasification has been extensively investigated. In this paper, a new co-gasification technology using coal and natural gas was developed. The distinct advantages of this technology are the excellent fuel flexibility and the availability to establish the gasifler by reconstructing the blast furnace or similar shaft furnace. Based on the concept of the new co-gasification technology, lab-scale experiments and modeling study were carried out. The obtained results indicate that gasification is undertaken at ideal thermodynamic environment where quasi-equilibrium could be reached without catalysts. The modeling results are in agreement with experimental data, demonstrating the validity of the model and that Aspen Plus is a useful tool for the analysis of the co-gasification process. Furthermore,the effect of major operation parameters, including oxygen flow rate and steam flow rate, on co-gasification process was investigated using the developed model.

Gasification of lignite from Polish coal mine to hydrogen-rich gas

The efforts of the world research activities involved in clean coal technologies development focus to a considerable extent on integrated hydrogen and power generation technologies based on coal gasification.As an alternative to combustion pro-cesses,gasification offers increased efficiency,lower negative environmental impact as well as wider application range of the main product—synthesis gas—in power generation and chemical syntheses.In order to select the most optimal lignite for the purpose of gasification,it is necessary to determine coal reactivity,the key parameter characterizing how fast the fuel reacts with the gasifying medium and controlling its process ability in thermochemical conversion to energy and/or energy carriers.This paper presents the experimental results of oxygen/steam gasification of lignite coal char in a fixed bed reactor under atmospheric pressure and at the temperature of 700,800 and 900℃;the samples come from an open pit lignite mine in the southwest of Poland.The effectiveness of the gasification process was tested in terms of the total gas and hydrogen yields,gas composition,carbon conversion rate and chars reactivity.

Simulation of Ash Deposition Behavior in an Entrained Flow Coal Gasifier

Fly ash deposition is an important phenomenon associated with ash/slag handling and discharge in the entrained-flow coal gasification process. Fouling and slagging inside the gasifier may cause reliability and safety problems because they can impose strong negative effects on the gasifier wall in the way of heat transfer and chemical corrosion. For these reasons, this study focuses on investigating the ash deposition distribution inside of a two-stage entrained-flow gasifier. The computational model is developed in order to simulate the gasification process with a focus on modeling ash formation, fly ash, and ash deposition. The Eulerian-Lagrangian approach is applied to solve the reactive thermal-flow field and particle trajectories with heterogeneous reactions. The governing equations include the Navier-Stokes equations, twelve species transport equations, and ten global chemical reactions consisting of three heterogeneous reactions and seven homogeneous reactions. The coal/ash particles are tracked with the Lagrangian method. The effects of different coal/ash injection schemes and different coal types on ash deposition have been investigated. The results show that the two-stage fuel feeding scheme could distribute the ash throughout a larger gasifier’s volume and, hence, could reduce the peak ash deposition rate and make the ash distribution more uniform inside the gasifier. Gasification of a high-ash coal results in a high ash deposition rate, low syngas higher heating value (HHV), and low carbon conversion rate. The result of ash deposition rate in this study can be used as a boundary condition to provide ash particle influx distribution for use in slagging models.

Characterization of Size and Density Separated Fractions of a Bituminous Coal as a Feedstock for Entrained Slagging Gasification

Coal is one of the main sources of energy in many parts of the world and has one of the largest reserves/production ratios amongst all the non-renewable energy sources. Gasification of coal is one among the advanced technologies that has potential to be used in a carbon constrained economy. However, gasification availability at several commercial demonstrations had run into problems associated with fouling of syngas coolers due to unpredictable flyash formation and unburnt carbon losses. Computer models of gasifiers are emerging as a powerful tool to predict gasifier performance and reliability, without expensive testing. Most computer models used to simulate gasifiers tend to model coal as a homogenous entity based on bulk properties. However, coal is a heterogeneous material and comminution during feedstock preparation produces particle classes with different physical and chemical properties. It is crucial to characterize the heterogeneity of the feedstocks used by entrained flow gasifiers. To this end, a low ash US bituminous coal that could be used as a gasifier feedstock was segregated into density and size fractions to represent the major mineral matter distributions in the coal. Float and sink method and sieving were employed to partition the ground coal. The organic and inorganic content of all density fractions was characterized for particle size distribution, heating value, ultimate analysis, proximate analysis, mineral matter composition, ash composition, and petrographic components, while size fractions were characterized for heating value, ash composition, ultimate and proximate analysis. The proximate, ultimate and high heating value analysis showed that variation in these values is limited across the range of size fractions, while the heterogeneity is significant over the range of density fractions. With respect to inorganics, the mineral matter in the heavy density fractions contribute significantly to the ash yield in the coal while contributing very little to its heating value. The ash yield across the size fractions exhibits a bimodal distribution. The heterogeneity is also significant with respect to the base-to-acid ratio across the size and density fractions. The results indicate that the variations in organic and inorganic content over a range of density and size classes are significant, even in the low ash, vitrinite rich coal sample characterized here. Incorporating this information appropriately into particle population models used in gasifier simulations will significantly enhance their accuracy of performance predictions.

Employment of Two-Stage Oxygen Feeding to Control Temperature in a Downdraft Entrained-Flow Coal Gasifier

The traditional practice of employing a two-stage coal-fed gasification process is to feed all of the oxygen to provide a vigorous amount of combustion in the first stage but only feed the coal without oxygen in the second stage to allow the endothermic gasification process to occur downstream of the second stage. One of the merits of this 2-stage practice is to keep the gasifier temperature low downstream from the 2nd stage. This helps to extend the life of refractory bricks, decrease gasifier shut-down frequency for scheduled maintenance, and reduce the maintenance costs. In this traditional 2-stage practice, the temperature reduction in the second stage is achieved at the expense of a higher than normal temperature in the first stage. This study investigates a concept totally opposite to the traditional two-stage coal feeding practices in which the injected oxygen is split between the two stages, while all the coal is fed into the first stage. The hypothesis of this two-stage oxygen injection is that a distributed oxygen injection scheme can also distribute the release of heat to a larger gasifier volume and, thus, reduce the peak temperature distribution in the gasifier. The increased life expectancy and reduced maintenance of the refractory bricks can prevail in the entire gasifier and not just downstream from the second stage. In this study, both experiments and computational simulations have been performed to verify the hypothesis. A series of experiments conducted at 2.5 - 3.0 bars shows that the peak temperature and temperature range in the gasifier do decrease from 600?C - 1550?C with one stage oxygen injection to 950?C - 1230?C with a 60 - 40 oxygen split-injection. The CFD results conducted at 2.5 bars show that 1) the carbon conversion ratio for different oxygen injection schemes are all above 95%;2) H2 (about 70% vol.) dominates the syngas composition at the exit;3) the 80% - 20% case yields the lowest peak temperature and the most uniform temperature distribution along the gasifier;and 4) the 40% - 60% case produces the syngas with the highest HHV. Both experimental data and CFD predictions verify the hypothesis that it is feasible to reduce the peak temperature and achieve more uniform temperature in the gasifier by adequately controlling a two-stage oxygen injection with only minor changes of the composition and heating value of the syngas.

“双碳”目标下清洁高效灵活煤电技术现状及煤电前景展望

阐述了“双碳”战略对煤电目前总体影响以及面临的发展问题;对煤电机组清洁排放、节能减碳、供热提效、灵活运行的现状和关键技术进行了梳理分析,展望了煤电发展前景,得出了基于我国资源禀赋及能源战略安全来积极看待煤电发展的结论,应重视清洁高效灵活煤电技术的研发与应用,与各种新能源的优势互补,动态协同发展,以推动新型电力系统稳健发展。

CHINA'S RECENT DEVELOPMENT IN COAL MINING,PROCESSING AND UTILIZATION

This paper describes the state-of-the-art and Outlook of coal mining and clean coal technology in China. As the major mining method,underground mining accounts for 96% of the total production. Among the state own mines, the percentage of mechanized mining reached 71 %. A rapid development of high-productive and high-profitable mines,especially those with longwall sublevel caving method, is described. The issues of heavy duty equipment, roof bolting,mine safety are also addressed. The Chinese government is paying more and more attention on the environmental problems inducing from coal mining,processing and utilization. A basic framework of clean coal technology is being formed and a wide range of technology is included.