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bjective Taking the coal chemical process of a company in Hami, Xinjiang as the research object, the problem of high energy consumption in the low temperature separation and liquefaction system of coal chemical syngas was solved. Methods Aspen HYSYS software was used to simulate the separation liquefaction process of the single mixed refrigerant synthetic natural gas. The distribution ratio of the component in mixed refrigerant and the first and second stage compression pressure of the mixed refrigerant cycle were optimized by using BOX algorithm, with the minimum specific power consumption of the system as the objective function and the minimum heat transfer temperature difference of the cold box as the constraint condition of 3 ℃. Results The results show that the cold-heat composite curve of the optimized cold box is closer and smoother and the heat exchange effects are optimized, while keeping the production of LNG and methanol raw gas unchanged, with overall power consumption of the system decreased by 16.59%, exergy efficiency increased from 37.96% to 43.04%, significantly increasing the energy utilization rate. Conclusions The optimization of mixed refrigerant ratio and compression pressure by BOX algorithm has a significant effect on reducing energy consumption of syngas liquefaction process and increasing exergy efficiency, which has reference significance for the research of low temperature separation and liquefaction process of syngas in coal chemical industry. [ABSTRACT FROM AUTHOR]

The study of pre-oxidation viscosity reduction technology of coal has been carried out on a fixed ffuidized bed device. The effects of temperature, atmosphere, residence time on the bond index were investigated. The results showed that the bond index could be reduced to below 5 under the conditions of temperature 200 °C, residence time 30 min, atmosphere air and air containing atmosphere, and the coke type has changed from F-type to C-type,and from weakly sticky coal to non sticky coal. By analyzing the com¬position of ZSLB and ZSLA tar products, it was found that tar of ZSLB and ZSLA mainly consists of naphthalene series, alkanes, phenols, phenanthrene series, benzene series, anthracene series, pyrene series, fluorene series, indene series, and other substances, with a similar proportion, with the highest content of naphthalene series; the content of low distillate substances in tar of ZSLB is higher, and the temperature corresponding to the same fraction is earlier, presents a lighter weight. [ABSTRACT FROM AUTHOR]

The research status of traditional gasification technology for hydrogen production from organic solid waste are reviewed, the influence of three main factors, gasification medium, gasification temperature and catalyst, on hydrogen production effect is analyzed in detail, by analyzing the action mechanism and summarizing the advantages and disadvantages in the application process, the technical disadvantages of this technology are put forward purposefully, it is pointed out that the technology should be developed from four aspects: mechanistic exploration, development of high-performance composite catalyst/catalyst with special structure, development of hydrogen production technology by co gasification with coal, and coupling with other new gasification hydrogen production technologies in the future, so as to better promote the industrial application of the technology. [ABSTRACT FROM AUTHOR]

The source and harm of oily sludge are briefly described.The thermal treatment technologies and characteristics of oily sludge, such as pyrolysis, coking, combustion and smoldering combustion are introduced.The types and characteristics of oily sludge combustion equipment are emphatically introduced.In view of the problem that a large amount of acid gas will be produced in the combustion and smoldering combustion process, which will further aggravate the corrosion of equipment, this paper summarizes the influence and control technology of the corrosion behavior of the oily sludge thermal treatment equipment, in order to provide a better reference for the corrosion control methods and development in the oily sludge thermal treatment process. [ABSTRACT FROM AUTHOR]

Coal chemical industry is a pathway for cleaner and more efficient consumption of coal. The modern coal chemical industry in China also acts as a national strategic technology reserve. However, high water demand by this industry and the high volume of outflow, often containing high levels of recalcitrant organic and inorganic pollutants, are some of the major environmental issues that need to be addressed. The implementation of new water treatment systems and the retrofit of existing water treatment facilities are of interest to both academia and the industry. This review selected coal gasification, coal liquefaction， and coking as three of the representative techniques, and briefly introduced the background, conversion processes， and then pinpointed the main wastewater discharge steps and the basic characteristics of the wastewater. At last， the review compiled representative research studies that apply electrochemical techniques in treating wastewater from the coal chemical industry and summarized the treatment mechanisms and performances. Recommendations for future study are provided accordingly. [ABSTRACT FROM AUTHOR]

As the economic development of China enters into a new normal, coal industry is changing greatly. To reduce the total cost of the coal supply industry in China and calculate the carbon emission of it, we developed the R-CSSM model based on linear program method to optimize the future pattern of China's coal production and transportation on the basis of the collection and analysis of the present situation of the coal supply industry and relevant policy. The carbon emission coefficients were calculated after we examined each link of the coal supply industry in different regions. Then we used these coefficients to calculate the carbon emissions from coal related activities under the optimized pattern. The results show that, under the existing arrangements and the constraints of resources and policy, China's coal production will continue to be centralized, the coal production of Shanxi, Shaanxi, Inner Mongolia, Ningxia, Gansu and Xinjiang will continue to rise, accounting for nearly 88% of all coal production in China by 2030, and this ratio rises by 17% compared with 2015. The pressure of coal transportation would increase first and then decrease, the railway transportation ability of Xinjiang, and southwestern and northeastern China for coal will be low, and railway expansion and reconstruction project need to be taken in these places. By 2020, the coal supply industry would have a total emission of about 641 million tons of carbon dioxide-equivalent, compared with 2015, and emission per unit of supply will fall by 8.75%. And the coal supply industry would have a total emission of about 526 million tons of carbon dioxide- equivalent in 2030, compared with 2015, emission per unit of supply will fall by 15.34%. Based on that, the coal production capacity, the coal transportation capacity, and the carbon emissions of coal supply industry in each province were analyzed. And the relevant suggestions for the development of China's coal industry have been put forward, which can provide a good support for the related decision making and the carbon emission reduction of coal industry. [ABSTRACT FROM AUTHOR]

With the deep coal mining in China, the contradiction between the mine water inrush from aquifer underling the coal seam and the decline ecological water level is more and more serious. Based on the analysis of the assemblage characteristics between the No. 5 coal seam and the aquifer(auifuge) in Chenghe mining area, the present study is to investigate the depth of destroyed floor by combining the theoretical calculation and in-situ measurement. The influence of coal seam mining on the confined water underling the coal seam has been studied from the perspective of aquifer structure, ecological water level and water quality. The results indicate that the maximum depth of destroyed floor of the No. 5 coal seam is 8-10. 8 m, and the main control factors of the depth of destroyed floor are the dip length of working face and the lithologic association of floor. And there is a positive correlation between the dip length of working face and the depth of destroyed floor, a negative correlation between lithologic association of floor and the depth of destroyed floor. Influence degree of the aquifer structure from large to small can be divided into Ⅰ,Ⅱ,Ⅲ level area, and the Ⅰ level areas are mainly distributed in the central-south and north,which covers an area of 6. 78 km2,accounting for 45． 2% of the total area; there is no obvious effect on water level and water quality. The paper puts forward a grouting reinforcement technology to protect water resources and stabilize the ecological water level in mining, and finds an effective way for the healthy development of coal industry in Weibei region. [ABSTRACT FROM AUTHOR]

In order to achieve the purpose of increasing more reclamation area and dump volume in the limited dump range, the reclamation area and dump volume were selected as the evaluation index of the dump optimize design, further followed the geometric parameters' adjustment to optimize the dump design when other influencing factors were optimal. The complexity relationship between geometric parameters and evaluation index was analyzed based on the dump surface area and dump volume calculation method. When the slope was stable, according to the characteristics of the three-dimensional space model,the geometric parameters of optimal geometric model of dump design was obtained by further dividing this area. The experimental results, based on the third dump of Yuanbaoshan opencast coal belong to Pingzhuang Coal Industry Group,show that the dump optimal design have achieved the desired effects. [ABSTRACT FROM AUTHOR]

Fully-mechanized top coal caving with large mining height is the main mining method for extra-thick coal seam. However, as the height of coal cutting and coal caving increases, prominent problems such as severe mine pressure behaviour severe rib spalling in working face, low top coal recovery rate and high gas emission rate and so on emerge. Based on the analysis of the development history of the fully-mechanized top coal caving in China, taking the working face 8105 at Tashan Coal Mine as the engineering background, authors studied the movement characteristics of the top coal and roof at the fully-mechanized top coal caving face with large mining height in the 14-20 m extra-thick coal seam, successfully developed key technologies such as the comprehensive prevention and control technology for rib spalling at the fully-mechanized top coal caving face with large mining height, high-efficient coal caving technology with high recovery rate and safety guarantee technology for mining under the condition of "low gas occurrence, high gas emission", etc. The underground test showed that the recovery rate at the fully-mechanized top coal caving face with large mining height 8105 at Tashan Coal Mine reaches 88. 9% which is 5.9% higher than that at working face 8104, the average operating rate of the equipment at the working face reach 92.1 %, and the raw coal produced at the face in 2011 reach 10.849 Mt, which achieve the objective of 10 Mt coal produced at the fully-mechanized top coal caving face with large mining height using domestic equipment in a year. [ABSTRACT FROM AUTHOR]

The slurry ability of lignite is too poor to be applied directly to coal-water slurry gasification technology. Luhuo lignite sample was pretreated differently by acid/water washing and pyrolysis in order to improve its slurryability. The treated samples were characterized by BET test, proximate analysis, ultimate analysis experiments, etc. The results show that the pore structure of the coal samples is destroyed by pretreatment, specific surface area decreases and average pore size increases, and the slurry concentration and mobility are improved. The concentration of coal water slurry can rise to 60% in the study of the slurryability of pretreated lignite washed with acid. The TherMax500 thermogravimetric apparatus was introduced to study the gasification characteristics of differently pretreated lignite. The results reveal that pretreatment with water washed has little effect on coal gasification reactivity, but acid washing pretreatment greatly reduces gasification reactivity of luhuo lignite. [ABSTRACT FROM AUTHOR]

In order to study the surface electric potential signals during the coal adsorbing gas, designed the experiment system of the coal adsorbing gas and tested the electric potential signal generated during the coal adsorbing gas under different gas pressure. Experiment results show that surface potential signals can be generated in the process of adsorbing gas, and they increases gradually along with the growth of adsorption time. For the same coal samples, different gas pressure from the coal surface potential signal to the first adsorption gas pressure of coal potential signal has a memory effect in the process of absorption. When the adsorption gas pressure is higher than the first adsorption gas pressure, the coal induces stronger surface potential signals. And when the adsorption gas pressure is lower than the first adsorption gas pressure, the coal induce weaker surface potential signals. The main reasons why surface potential signals can be generated from coal adsorbing gas are that the gas seepage in coal pores produces flow potential and free charge is generated when the gas damages micro cracks and crack of coal. [ABSTRACT FROM AUTHOR]

In order to scientifically optimize well mining working face advancing direction, further improving the coal recovery rate at the same time to guarantee the stability of slope, under the background of open-underground mining engineering practice in Pingshuo mining area, through similarity simulation, the different influence about deformation and failure of along slope mining and inverse slope mining under end slope coal pillar recovery was studied. Then mechanics model was constructed to analyze why the working face wall side caving angle is less than open-off cut side caving angle. The result shows that in the geological and mining conditions of Pingshuo mining area, the working face wall side caving angle is 7°,less than open-off cut side caving angle because of different overburden fracture mechanism, and the along slope mining is conducive to the slope stability. Based on the above conclusions, if use the along slope mining way, not only can reduce the influence of deformation and failure to the slope, but also can further narrow the boundary parameters of open-underground mining, and produce more end slope coal. [ABSTRACT FROM AUTHOR]

This paper aimed at the problems such as low restoration rate of land resources and long time for subsidence land reclamation by traditional technology with the condition of final subsided status. Based on the introduction and discussion of the research history for unsteady subsidence land reclamation, the concept of concurrent mining and reclamation (CMR) was proposed. The connotation, principles, technical classifications, and key technologies of CMR for underground coal mining were presented. The advantages with high reclamation percentage of land resources for the new technology were proved based on a case study, which indicated that CMR could increase farmland reclamation percentages to 37. 59% comparing with the farmland reclamation percentage of post-mining. The scope of application and application prospects of the technology were also discussed, CMR could be used in 5 of the 14 large coal bases. It is estimated that the application of CMR could increase land area by 6 680. 8 km². [ABSTRACT FROM AUTHOR]

Based on thirteen exploratory reports for coal mines form Bijie City, Guizhou Province, data about basic coal features such as sulphur content, ash yield, ash composition and concentration of eleven trace elements as Ge, Ga, U, Th, V, Cl, As, F, Pb, Cu and Zn was systematically analyzed and modeled, and the distribution characteristics, occurrence modes and controlling factors of those trace elements in Bijie coal were investigated. In order to obtain a relative accurate content level of those eleven trace elements in Bijie coal, a parameter called "Reserves Weight Coefficient" was applied. Results show that in Bijie coal Pb, Cu, Zn, U and V are abnormally enriched, Ga is relatively enriched, F and Th are slightly enriched while Ge and Cl are both lower than the Clarke Value, concentration of As in Bijie coal is higher than the common Chinese coal but markedly lower than the USA coal. Correlativity analysis reveals that F may occurs in carbonate minerals, Pb and Cu are probably hosted in sulphide minerals and Cu shows a certain degree of organic affinity. Evidence suggests that on the one hand enrichment of Cu, Zn and V in Bijie coal can be attributed to Emeishan basalt in terrigenous province whose content of those three elements are relatively high; on the other hand trace elements enrichment in coal are controlled by sedimentary environment, specifically some elements that migrate easily in continental sedimentation process such as Ge, Ga and Th tend to be of higher content in coal when the seawater influence is weakening. V is enriched in coal when the influence is strong. In addition, some elements' abnormal enrichment in Bijie coal is believed to be linked with the tectonic movement especially hydrothermal fluid. [ABSTRACT FROM AUTHOR]

To solve the problem of high dust concentration caused by rock tunnel excavation, in view of the characteristics of dust produced and analyzing the processes of roadheader cutting rock, the paper used Fluent software to carry on numerical simulation of dust movement and analyse the dust characteristics of motion and concentration distribution. Simultaneously, this paper designed the foam dust suppression system applied to fully mechanize large cross-section rock tunnel excavation on the principle of foam dust suppression, and put it into application at the driving face of the north main haulage roadway in Zhuxianzhuang Coal Mine, Huaibei Mining Co., Ltd. The results show that the dust concentration on the exhaust section of the driving face, reaches a maximum at the leeward side of dust source. Foam making by the foam dust suppression system can enclose roadheader's cutting head and cover palisades, reaching the results of wetting rock, reducing dust content, depressing the generation of dust and blocking the spreading alleyway. The average dust-settling effect is 86. 2% and 84. 4% for the total dust and respirable dust, and the effect is 3. 6 and 4. 6 times comparing with water spray, achieving a good effect. [ABSTRACT FROM AUTHOR]

Based on analyzing the reasons and characteristics of gas combustion under coal mine and integrating the situation of gas combustion accident which frequently occured at present, the authors built the experimental platform with the ultra fine water mist to prevent gas combustion. A series of experiments with the ultra fine water mist to prevent gas combustion was conducted. Finally, the best operation parameter to study the water mist restrained gas combustion was obtained with the methane flow of 150 mL/min, the methane concentration of 90%, the atomization quantity of 220 mL/min, and the water spray particle size of 5-30 µm. The results show that after release ultra fine watermist,a closed spray ring is formed around the gas flame, and the gas flame interact with ultra fine water mist appears the process of restrained-cut flame-restrained again-cut flame again, with the gas flame gradual becoming smaller until to extinguish. Comparing with free combustion, the temperature and oxygen concentration around gas flame all reduced with different degree, and the whole process of flame extinguish is only 90 s. [ABSTRACT FROM AUTHOR]

The field tests, which were conducted in an island longwall panel in the Tangshan Coal Mine in the city of Tangshan, China, are intended to provide researchers and mining engineers with the assessment of coal bump risk during extraction of an island longwall panel. In these tests, roadway roof displacement and electromagnetic radiation (EMR) of roadways in the panel were investigated to determine the zones of intensive roof deformation. The results of the field tests show that the roof deformation starts to occur at more than 30 m ahead of the longwall face and the deformation starts to accelerate after a distance of 10 m in front of the longwall face. Large and rapid roof deformation is considered to be an important precursor of coal bump occurrence during the extraction of an island longwall panel. It indicates that the bump-prone zones around island longwall panel and near the edge of the roadway during extraction is within 7.5 to 10. 0 m ahead of the mining face. [ABSTRACT FROM AUTHOR]

Through the industry linkage analysis of coal and related industries, three basic types of coal industry chain were brought forward. Gave the evaluation method of the industry chain efficiency based on date envelopment analysis (DEA), evaluated the operating efficiency of coal industry chain of 19 regions in China. It turns out that different provinces are different in the coal industry chain efficiency, and the eastern provinces are higher than the middle and western regions. Finally, this paper explored the development strategy of coal industry chain. [ABSTRACT FROM AUTHOR]