Nowadays,the evaluation of coal deposits becomes crucial,due to many uncontrollable factors,which affect the energy sector.A comparative evaluation of coal deposits is essential for their hierarchical classification r...Nowadays,the evaluation of coal deposits becomes crucial,due to many uncontrollable factors,which affect the energy sector.A comparative evaluation of coal deposits is essential for their hierarchical classification regarding their sustainable exploitation,when compared to other coal deposits or competitive fuels,which may be used as alternative solutions for electricity generation.In this paper,a method for spatial analysis and evaluation of a lignite deposit is proposed,by creating four spatial key indicators via GIS analysis,which are then aggregated by applying a weighted linear combination.The analytical hierarchy process is applied to estimate the relative weights of the indicators,in order to perform a weighted cartographic overlay.Through the synthesis of the indicators,an overall,total spatial quality indicator is calculated.The weighted analysis was shown to be more effective compared to the unweighted one,because it can provide more reliable results regarding the exploitation of the examined lignite deposit.The implementation of GIS-based analytical hierarchy process in spatial analysis and evaluation of lignite deposits,in terms of sustainable exploitation,demonstrates that this method can be extensively applied for evaluating the economic potential of mineral deposits.展开更多
The goal of this study was to investigate coal quality features and their relationship to coal spontaneous combustion characteristics in multi-seam coal mines to better predict when coal spontaneous combustion is like...The goal of this study was to investigate coal quality features and their relationship to coal spontaneous combustion characteristics in multi-seam coal mines to better predict when coal spontaneous combustion is likely to occur.To that end,coal samples of various particle sizes were obtained from five coal seams(Nos.6,8,9,12 and 20)in the Shuangyashan City Xin’an Coal Mine.The samples were then respectively heated using a temperature programming system to observe and compare similarities and differences in the sponta-neous combustion process of different particle sizes in response to rising temperature.The experimental results show,that in all five coal seams,the concentration of CO,C_(2)H_(4),and C_(2)H_(6) increased with a certain degree of regularity as a function of rising temperature.However,of these three gasses,only CO and C_(2)H_(4) can be used as indicators to predict coal mine spontaneous combustion.The critical temperature for samples from all five coal seams ranged from 50–85℃,while the dry cracking temperature of coal seams 8 and 12(80–100℃)were lower than those of 6,9,and 20(100–120℃).Furthermore,the production rate of CO,C_(2)H_(4),and C_(2)H_(6) is related to both coal particle size and temperature.The smaller the particle size,the faster the production rate;and the higher the temperature,the more gas that gets produced.All five coal seems are mainly com-posed of long flame coal.However,they differ in that the No.12 coal seam contains weak cohesive coal;the No.8 coal seam contains lean and gas coal;and the Nos.6,9,and 20 coal seams contain a certain amount of anthracite.During the programmed coal heating,the CO,C_(2)H_(4),and C_(2)H_(6) release trend for the coal seams was No.12>No.8>Nos.6,9,and 20.These results demonstrate that the presence of weak cohesive coal and anthracite highly influence the concentration of CO,C_(2)H_(4),and C_(2)H_(6) released during coal spontaneous combustion.展开更多
In order to investigate the correlation between the variations in the environmental water quality indexes and the distance of water bodies from the planting region of vetiver, samples of surface water were gathered fr...In order to investigate the correlation between the variations in the environmental water quality indexes and the distance of water bodies from the planting region of vetiver, samples of surface water were gathered from the water bodies surrounding an abandoned coal gangue mountain of Dahead coal mine (Dahe, Liupanshui, Guizhou Province) based on the method of field survey and typical analysis. According to the results, the planting of vetiver could effectively purify the water bodies surrounding the coal gangue mountain. Detailed findings include three aspects:(1) The main pollutants detected in water bodies around the coal gangue mountain were SO4 2-, NO3 -, Fe and Cu, with a concentration of 869.45, 35.16, 26.06, and 40.85 mg/L respectively in wet season and all exceeded the national environmental standards for surface water.(2) The pH values of water bodies 150~200 m away from the vetiver planting region stayed within the limits of national environmental standards for surface water and presented a homogeneous feature, revealing that vetiver has the capacity to adjust the pH of the surrounding water body.(3) The contents of Fe, Mn, Cu, SO4 2-, and NO3 - under all treatments, tended to increase with the increasing distance of water bodies from the vetiver planting region;it means the shorter the distance between the water body and the vetiver planting region is, the higher the adsorption rate and purification effects will be;the optimal concentrations of Fe, Mn, and Cu were 0 mg/L, much lower than the national environmental standards for surface water.展开更多
Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The pape...Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The paper mainly focuses on the progress of the past few years in the fundamentals, data pretreatment, calibration model, and experimental issues of LIBS and its application to coal analysis. Many important domestic studies focusing on coal quality analysis have been conducted. For example, a proposed novel hybrid quantification model can provide more reproducible quantitative analytical results; the model obtained the average absolute errors (AREs) of 0.42%, 0.05%, 0.07%, and 0.17% for carbon, hydrogen, volatiles, and ash, respectively, and a heat value of 0.07 MJ/kg. Atomic/ionic emission lines and molecular bands, such as CN and C-2, have been employed to generate more accurate analysis results, achieving an ARE of 0.26% and a 0.16% limit of detection (LOD) for the prediction of unburned carbon in fly ashes. Both laboratory and on-line LIBS apparatuses have been developed for field application in coal-fired power plants. We consider that both the accuracy and the repeatability of the elemental and proximate analysis of coal have increased significantly and further efforts will be devoted to realizing large-scale commercialization of coal quality analyzer in China.展开更多
为解决传统多元线性回归(Multivariate linear regression,MLR)模型在煤炭发热量预测方面精度不足和适用性有限的问题,提出了一种基于改进自适应增强算法(Adaptive boosting,Adaboost)的煤发热量的预测模型。将随机森林(Random forest,...为解决传统多元线性回归(Multivariate linear regression,MLR)模型在煤炭发热量预测方面精度不足和适用性有限的问题,提出了一种基于改进自适应增强算法(Adaptive boosting,Adaboost)的煤发热量的预测模型。将随机森林(Random forest,RF)作为Adaboost的基学习器,以提高模型在工业煤质分析中的发热量预测精度和泛化能力。研究基于某电厂1万组入炉煤的工业分析数据,选取水分、挥发分、灰分和固定碳作为模型输入,建立煤炭低位发热量的预测模型。通过与传统的多元线性回归方程及其他非线性模型比较,模型展现出更高的预测精度和更好的泛化能力。大样本测试的实验结果表明,本模型的平均绝对百分比误差为0.5417%,均方根误差为0.1304 MJ/kg,拟合度(R^(2))达到0.9799,其在煤炭发热量预测方面优于其他模型。此外,200组真实的混煤工业分析数据的模拟验证,进一步确认了本模型较优的泛化性能。展开更多
文摘Nowadays,the evaluation of coal deposits becomes crucial,due to many uncontrollable factors,which affect the energy sector.A comparative evaluation of coal deposits is essential for their hierarchical classification regarding their sustainable exploitation,when compared to other coal deposits or competitive fuels,which may be used as alternative solutions for electricity generation.In this paper,a method for spatial analysis and evaluation of a lignite deposit is proposed,by creating four spatial key indicators via GIS analysis,which are then aggregated by applying a weighted linear combination.The analytical hierarchy process is applied to estimate the relative weights of the indicators,in order to perform a weighted cartographic overlay.Through the synthesis of the indicators,an overall,total spatial quality indicator is calculated.The weighted analysis was shown to be more effective compared to the unweighted one,because it can provide more reliable results regarding the exploitation of the examined lignite deposit.The implementation of GIS-based analytical hierarchy process in spatial analysis and evaluation of lignite deposits,in terms of sustainable exploitation,demonstrates that this method can be extensively applied for evaluating the economic potential of mineral deposits.
基金support from the Major Project of Engineering Science and Technology in Heilongjiang Province in 2020(Grant No.2020ZX04A01)support from the Scientific Research Projects of Undergraduate Universities in Heilongjiang Province(Grant No.2020-KYYWF-0534).
文摘The goal of this study was to investigate coal quality features and their relationship to coal spontaneous combustion characteristics in multi-seam coal mines to better predict when coal spontaneous combustion is likely to occur.To that end,coal samples of various particle sizes were obtained from five coal seams(Nos.6,8,9,12 and 20)in the Shuangyashan City Xin’an Coal Mine.The samples were then respectively heated using a temperature programming system to observe and compare similarities and differences in the sponta-neous combustion process of different particle sizes in response to rising temperature.The experimental results show,that in all five coal seams,the concentration of CO,C_(2)H_(4),and C_(2)H_(6) increased with a certain degree of regularity as a function of rising temperature.However,of these three gasses,only CO and C_(2)H_(4) can be used as indicators to predict coal mine spontaneous combustion.The critical temperature for samples from all five coal seams ranged from 50–85℃,while the dry cracking temperature of coal seams 8 and 12(80–100℃)were lower than those of 6,9,and 20(100–120℃).Furthermore,the production rate of CO,C_(2)H_(4),and C_(2)H_(6) is related to both coal particle size and temperature.The smaller the particle size,the faster the production rate;and the higher the temperature,the more gas that gets produced.All five coal seems are mainly com-posed of long flame coal.However,they differ in that the No.12 coal seam contains weak cohesive coal;the No.8 coal seam contains lean and gas coal;and the Nos.6,9,and 20 coal seams contain a certain amount of anthracite.During the programmed coal heating,the CO,C_(2)H_(4),and C_(2)H_(6) release trend for the coal seams was No.12>No.8>Nos.6,9,and 20.These results demonstrate that the presence of weak cohesive coal and anthracite highly influence the concentration of CO,C_(2)H_(4),and C_(2)H_(6) released during coal spontaneous combustion.
文摘In order to investigate the correlation between the variations in the environmental water quality indexes and the distance of water bodies from the planting region of vetiver, samples of surface water were gathered from the water bodies surrounding an abandoned coal gangue mountain of Dahead coal mine (Dahe, Liupanshui, Guizhou Province) based on the method of field survey and typical analysis. According to the results, the planting of vetiver could effectively purify the water bodies surrounding the coal gangue mountain. Detailed findings include three aspects:(1) The main pollutants detected in water bodies around the coal gangue mountain were SO4 2-, NO3 -, Fe and Cu, with a concentration of 869.45, 35.16, 26.06, and 40.85 mg/L respectively in wet season and all exceeded the national environmental standards for surface water.(2) The pH values of water bodies 150~200 m away from the vetiver planting region stayed within the limits of national environmental standards for surface water and presented a homogeneous feature, revealing that vetiver has the capacity to adjust the pH of the surrounding water body.(3) The contents of Fe, Mn, Cu, SO4 2-, and NO3 - under all treatments, tended to increase with the increasing distance of water bodies from the vetiver planting region;it means the shorter the distance between the water body and the vetiver planting region is, the higher the adsorption rate and purification effects will be;the optimal concentrations of Fe, Mn, and Cu were 0 mg/L, much lower than the national environmental standards for surface water.
文摘Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical spectroscopy technique. This review presents the main recent developments in China regarding the implementation of LIBS for coal analysis. The paper mainly focuses on the progress of the past few years in the fundamentals, data pretreatment, calibration model, and experimental issues of LIBS and its application to coal analysis. Many important domestic studies focusing on coal quality analysis have been conducted. For example, a proposed novel hybrid quantification model can provide more reproducible quantitative analytical results; the model obtained the average absolute errors (AREs) of 0.42%, 0.05%, 0.07%, and 0.17% for carbon, hydrogen, volatiles, and ash, respectively, and a heat value of 0.07 MJ/kg. Atomic/ionic emission lines and molecular bands, such as CN and C-2, have been employed to generate more accurate analysis results, achieving an ARE of 0.26% and a 0.16% limit of detection (LOD) for the prediction of unburned carbon in fly ashes. Both laboratory and on-line LIBS apparatuses have been developed for field application in coal-fired power plants. We consider that both the accuracy and the repeatability of the elemental and proximate analysis of coal have increased significantly and further efforts will be devoted to realizing large-scale commercialization of coal quality analyzer in China.
