Clean coal geology in China:Research advance and its future

In China,the connection between coal utilization and environmental pollution has been increasingly evident due to the rapid growth in energy consumption.Clean coal technology(CCT)is one of the effective methods to address coal-associated pollution.However,CCT needs the practical and theoretical support of clean coal geology(CCG).In this paper,a new definition of CCG is proposed,based on the definitions of coal,coal geology,and CCT,combined with the development of national CCG.CCG is the discipline comprehensively researching the genesis,nature,distribution,cleaning potential,clean utilization and environmental effects of resources(coal,coal bed methane,and other coal-associated resources)that can be cleaned by CCT.The research content of CCG is discussed from different aspects,such as cleaning potential evaluation,geological guarantee for coal mining,ash yields and sulfur contents,trace elements,pollution caused by coal,and mine reclamation.The progress of CCG in China is also briefly divided into four stages and delineated.Finally,scientific problems in CCG are summarized and an outlook for CCG is given.

Insights from principal component analysis applied to Py-GCMS study of Indian coals and their solvent extracted clean coal products

The present work aims at studying five Indian coals and their solvent extracted clean coal products using Py-GCMS analysis and correlating the characterization data using theoretical principal component analysis.The pyrolysis products of the original coals and the super clean coals were classified as mono-,di-and tri-aromatics,while other prominent products that were obtained included cycloalkanes,n-alkanes,and alkenes ranging from C_(10)-C_(29).The principal component analysis is a dimensionality reduction technique that reduced the number of input variables in the characterization dataset and gave inferences on the relative composition of constituent compounds and functional groups and structural insights based on scores and loading plots which were consistent with the experimental observations.ATR-FTIR studies confirmed the reduced concentration of ash in the super clean coals and the presence of aromatics.The Py-GCMS data and the ATR-FTIR spectra led to the conclusion that the super clean coals behaved similarly for both coking and noncoking coals with high aromatic concentrations as compared to the raw coal.Neyveli lignite super clean coal was found to show some structural similarity with the original coals,whereas the other super clean coals showed structural similarity within themselves but not with their original coal samples confirming the selective action of the e,N solvent in solubilizing the polycondensed aromatic structures in the coal samples.

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.

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.

Effect of a starch-based filter aid on the dewatering of fine clean coal

The dewatering of fine, flotation cleaned coals from Huaibei and Xuzhou (bituminous) and Yongcheng (anthracite) were studied. The supernatant and filter cake were examined to determine the rate and extent of flocculation and dewatering. A starch-based filter aid was used to increase flocculation and dewatering rates. The filtration constant, K, and compression index, s, of the Yongcheng slurry were measured under various conditions. A designed experiment was performed to determine optimum conditions for dewatering. The results showed that the filter aid enhanced flocculation and coagulation of the fine cleaned coal slurry, enhanced the structure of the filter cake and promoted dewatering of the cake. Moisture content in the cake was reduced to 17% after vacuum filtration.

Physical properties and filter cake structure of fine clean coal from flotation

In order to improve the dewatering rate and the effect of fine clean coal(FCC), the advanced method offine coal( 0.5 mm) dewatering and the correlated basic theory were investigated in this study. It was found that the dewatering by sleeve type press filter was an efficient way of FCC dewatering. On the other hand, the results also proved that particle size distribution, volatile matter, ash content, pore size distribution and specific surface area of coal particles of FCC samples, as well as viscosity and density of FCC slurry, were important parameters in determining the process of efficient dewatering. Especially, wet mass to dry mass, specific resistance of average mass, compressibility factor and microstructure of filter cake explained the reasons and mechanisms of fine clean coal efficient dewatering.

Triboelectrostatic Separation-an Efficient Method of Producing Low Ash Clean Coal

At present, coal is mainly consumed as fuel. In fact, coal is also a kind of precious raw material in chemical industry on the premise that some harmful minerals should be removed from coal. The paper presents the results of the research on producing low ash (<2%) coal with triboelectrostatic separator used for producing high-grade active carbon. The test is conducted in bench-scale system, whose capacity is 30～100 kg/h. The results indicate that: 1) the ash content of clean coal increases with the increase of solid content of feedstock, on the contrary, the yield of clean coal is declining; 2) a high velocity may result in a good separation efficiency; 3) for the same solid content, the reunion caused by intermolecular force makes the separation efficiency drop down when the ultra-fine coal is separated; 4) the separation efficiency is improved with the increase of electric field intensity, but there is a good optimized match between the electric field intensity and yield of clean coal; 5) a low rank coal is easy-to-wash in triboelectrostatic separation process; 6) the yield of clean coal can be enhanced and the ash decreased through adapting optimized conditions according to various coals.

Preparation of Ultra-Clean Coal by Selective Oil Agglomeration

This paper deals with the preparatiou of ultra-clean coals by selective oil agglomeration. It has been found that the deashing method used has high deashing rate and high combustible recovery but low oil consumption. So it will be widely used in the future. The ash content of coal 1# and 2# is reduced to less than 1%. It has been summarized that the main factors affecting deashing are coal rank, oil consumption, pulp density as well as particle size.

A New Parameter of Cleanability to Determine the Clean Potential of Coal Resources

Objective This work is based on analysis on large numbers of coal data such as the latest national coal potential evaluation data and previous data published by REN Deyi, TANG Xiuyi and LU Xukun, and the evaluation methods of clean potential of coal resources proposed by predecessors. It is found that previous method rank coal is only in accordance with raw coal or washed coal, which fail to take full account of the changes in elements before and after coal washing. Some elements can be removed by washing or other methods, and others may be even enriched after the coal is washed. For this reason, this work defined a new parameter of cleanability and developed its calculation formula to determine the clean potential of coal resources. Cleanability is a comprehensive indicator based on the removal rate of each indicator harmful element in coal. The clean potential of coal is proportional to the value of cleanability. The higher the cleanability value is, the better the clean potential is, and vice versa.

Clean Processing and Utilization of Coal Energy

The dominant status of coal on the energy production and consumption structure of China will not be changed in the middle period of this century. To realize highly efficient utilization of coal,low pollution and low cost are great and impendent tasks. These difficult problems can be almost resolved through establishing large-scale pithead power stations using two-stage highly efficient dry coal-cleaning system before coal burning,which is a highly efficient,clean and economical strategy considering the current energy and environmental status of China. All these will be discussed in detail in this paper.

Study on characteristics of pipeline transportation and sulfur fixing of cleaned coal logs

As special cylindrical briquettes of coal for long distance pipeline transportation and directly cleaned combustion the cleaned coal logs should possess two characteristics of transportation in pipeline and cleaned combustion. In order to make cleaned coal logs a rational technology for manufacturing, cleaned coal logs was designed and compound sulfur fixing binders with high effects of binding and sulfur-fixing was selected and combined. In addition, by means of characteristic experiments of strength, wear, waterproof and sulfur-fixing five different cleaned coal logs made with different compound sulfur fixing binders in different compaction conditions was tested and measured. Experimental results indicated that the manufacturing technology of cleaned coal logs was reasonable and the combination of compound sulfur fixing binders was scientific. Cleaned coal logs made up with the fourth group of coal mixture had high strength, good waterproof property, efficient sulfur-fixing, good characteristic of transportion, and achieved the performance requirement for pipeline transportation and sulfur fixing.

Co-gasification of coal and biomass an emerging clean energy technology: Status and prospects of development in Indian context

Co-gasification of coal and biomass is emerging as potential clean fuel technology to achieve high thermodynamic efficiency with relatively low CO2 emission. The coal and biomass have been exclusively gasified more than a century to obtain gas–liquid fuels and the production of chemicals. Co-gasification has higher efficiency than the solitary coal gasification because the cellulose, hemicellulose and lignin content of biomass help to ignite and enhance the rate of gasification. It is suggested that the extensive research on carbon reactivity pattern, heat release, reaction kinetics, etc. may support to reduce the uncertainties in the co-gasification performance of coal and biomass blends, particularly in India. The prospects of co-gasification technology in Indian context have been discussed considering the abundance of varieties of coal and biomass. The suitability of existing gasifier procedures and their limitations with operating parameters like temperature, residence time, density optimisation, feed rate, agglomeration intensity, the tar formation and techno-economics involved are described. Also, this paper reviews the research highlights of the history of co-gasification and the advancement in upcoming challenges like a design of gasifier, access and preparation of biomass, disposal of residue, environmental concerns and reassurance to the operators for execution of large and small-scale projects.

Intelligent and ecological coal mining as well as clean utilization technology in China: Review and prospects

Coal is an essential fossil fuel in China; however, coal mining and its utilization are being under the increasing pressure from ecological and environmental protection. Therefore, the consulting project "Technical Revolution in Ecological and Efficient Coal Mining and Utilization & Intelligence and Diverse Coordination of Coal-based Energy System," initiated by Chinese Academy of Engineering, puts forward three stages(3.0, 4.0 and 5.0) of China's coal industry development strategy. Aimed at "reduced staff,ultra-low ecological damage, and emission level near to natural gas," breakthroughs should be achieved in the following three key technologies during the China Coal Industry 3.0 stage(2016–2025): including intelligent coal mining, ecological mining, ultra-low emission and environmental protection. This paper focuses on the development trends of the China Coal Industry 3.0 and its support for China Coal Industry 4.0 and 5.0 is analyzed and prospected as well, which may offer technical assistance and strategy orientation for realizing the transformation from traditional coal energy to clean energy.

Life Cycle Assessment of Ultra-clean Micronized Coal Oil Water Slurry

Life cycle assessment is applied to assess the ultra-clean micronized coal oil water slurry (UCMCOWS) with SimaPro and the environmental impact of UCMCOWS on its whole life cycle is also analyzed. The result shows that the consumption of energy and products are increasing along with the deepening of UCMCOWS processing, UCMCOWS making and combustion are the two periods which have a bigger impact on eco-system and human health. As a new substitute of fuel, UCMCOWS merits to be utilized more efficiently and reasonably.

Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants

Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.

Cleaning of South African coal using a compound dry cleaning apparatus

复合干燥清洗原则简短被描述。南非的煤上的 beneficiation 测试用模型混合物被进行干燥清洗仪器。优秀结果被获得，操作参数的最佳是坚定的。他们是：3.0 公里， 47.5 Hz 的马达频率， 50% 的空气体积， 7 掳的一个横向的角度，和一个纵的角度的一个振幅 ? 2 掳。这些条件产出包含 11% 灰和 75% 的煤生产的干净的煤。器官的效率，畏，是 95.86% 。这些结果证明南非的煤能被复合干燥清洗有效地分开，它将推广复合干燥清洗方法。