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Structure Optimization And Drilling Capacity Analysis Of A Self-Propelled Straight-Swirling Mixed Jet Bits, Du Peng, Zhang Wending

Coal Geology & Exploration

As the core part of hydro-jet radial drilling technology for coal-measure gas extraction, the self-propelled jet drill bit has a decisive impact on drilling efficiency. In order to obtain the optimal parameters of the direct rotating mixed jet, the velocity characteristics of the three-dimensional flow field with different bit structure parameters are analyzed by the combination of Fluent numerical simulation and specific experiments, and the optimization criteria are given. The optimal parameters of the drill bit are obtained in the drilling test: the central hole of diameter 1.2 mm, the impeller groove of width 0.7 mm, the impeller of thickness …

Review Of A Framework For Sustainable Thinking: Is Ql For Citizenship Even Possible?, Nathan D. Grawe

Numeracy

Van Antwerp and Heun's A Framework for Sustainability Thinking offers an extensive collection of data related to sustainability with an emphasis on energy. Intended for a primary audience of undergraduate students, the authors set the data in the context of the IPARX identity which notes that impacts (I) are the product of population (P), affluence (A), resource intensity of economic activity (R), and impact of the resources (X). In addition to being a useful text for seminars focused on sustainability and energy use, the book provides a context for contemplating the roles of expertise vs. general quantitative literacy when addressing …

Research Advances Into Mine Safety Science And Engineering, Hani Mitri, Rudrajit Mitra, Ting Ren

Journal of Sustainable Mining

No abstract provided.

Carbon Capture, Utilization, And Storage, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about carbon capture, utilization, and storage (CCUS) and the Energy & Environmental Research Center’s CCUS capabilities. Includes information on the Plains CO₂ Reduction (PCOR) Partnership initiative, Brine Extraction and Storage Test (BEST), Carbon Storage Assurance Facility Enterprise (CarbonSAFE), Red Trail Energy Carbon Capture and Storage, a feed study at Coal Creek Station, Bell Creek and Cedar Creek anticline projects, and Partnership for CO₂ Capture (PCO₂C). [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Study On The Effect Of Coal Microscopic Pore Structure To Its Spontaneous Combustion Tendency, Xianwei Dong, Gaojing Li, Xuanmeng Dong, Fusheng Wang

Journal of Sustainable Mining

Coal is a porous medium. Due to the large number of pores in coal and the pore size on its surface, usually ranging from millimeter to nanometer, it is difficult to measure and analyze the microscopic pore structure of coal. In order to investigate the effect of the microscopic pore structure of coal on its spontaneous combustion tendency, coal samples from different coal mines of the Kailuan Group were selected as the research objects, and the data of the microscopic pore distribution of three different coal samples were measured by using mercury injection apparatus. The regression analysis of microscopic pore …

Potential Economic And Environmental Benefits Of Faecal Sludge Derived Compost And Char Briquettes: The Case Of Dar Es Salaam, Tanzania, Isabela T Mkude, Richard Kimwaga, Sara Gabrielsson

Tanzania Journal of Science

The concept of resource recovery, particularly from waste has recently gained much attention and popularity. The aim of this study was to quantify the potential economic and environmental benefits of recovering nutrients and energy from faecal sludge (FS). The empirical data were collected from three unplanned settlements of Dar es Salaam City at Keko, Kipawa and Manzese. Two scenarios were developed to recover nutrients and energy. The estimations of potential amounts of compost and char briquettes were performed by using the resource value mapping (REVAMP) tool. Results from REVAMP indicated daily economic benefits across the study areas ranging between 680 …

Multiple Solar Receivers Arrangement For High-Temperature Power Generation And Applications, Diego Jesus Guillen Perez

USF Tampa Graduate Theses and Dissertations

This dissertation presents an investigation of the specification and operation of multiple central solar receivers (CSR) sharing a heliostat field and an analysis of the receiver's thermal performance. A heliostat field was modeled in which different parts of the field aimed at different external or cavity receivers located on the same tower. Optical and thermal performance are analyzed, including the receivers' heat flux, solar thermal efficiency, and annual energy output. Some of the contributions of this research are:

1. Propose a novel configuration for a CSP power generation system using two receivers in a single central tower suitable …

Q-P Curve Equation Of Geothermal Well Recharge Test In The Urban Area Of Mei County, Western Guanzhong, Shen Xiaolong, Li Hao, Wang Wei, Cheng Zhouying

Coal Geology & Exploration

Clarifying the relationship between recharge pressure (p) and recharge volume (Q) is crucial for regional green and sustainable geothermal development in geothermal well recharge. The preliminary data of well G102 recharge test in Mei County in the western Guanzhong area were optimized, and three sets of data were determined to clarify this relationship. According to the data, the Q-p curve was drawn. Based on the characteristics of five types of curves in the pressurized water test, it was judged that the curves might be parabolic, logarithmic, and hower function. Therefore, three types of curves were drawn, …

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.

Experimental Study On The Migration And Distribution Law Of Pulverized Coal In Roadway During Coal And Gas Outburst, Zhang Chaolin, Wang Yibo, Wang Enyuan, Zeng Wei, Wang Peizhong

Coal Geology & Exploration

Coal and gas outburst is one of the geological disasters that seriously threaten coal mine safety production, and its main disaster forms are gas suffocation, impact and burial of pulverized coal. In this paper, the coal and gas outburst experiments under different gas pressures were carried out using the self-developed multi-functional test system for coal and gas outburst simulation. The results show that the gas entrains the pulverized coal and sprays into the roadway in a jet shape after the outburst is triggered. The gas expansion energy is under the pressure of 0.35 MPa and the initial acceleration of outburst …

Risk Assessment Of Floor Water Inrush By Weighted Rank Sum Ratio Based On Combination Weighting, Yao Hui, Yin Shangxian, Xu Wei, Zhang Runqi, Jiang Zhiting

Coal Geology & Exploration

Deep mining of the coal seam causes frequent water hazards in the coal mine floor. As the disadvantages of traditional water inrush risk assessment methods, such as single evaluation index and deviation of the evaluation results from reality are gradually revealed, many new assessment methods are emerging. In this paper, Donghuantuo Coal Mine, a North China type coalfield, in Hebei province is taken as the research object. The evaluation factor sets including aquifer capacity, aquifuge capacity, geological conditions and coal seam conditions are selected, and with ten evaluation factors being considered, a floor water inrush risk evaluation index system applicable …

Cross Wavelet Analysis Between Layered Monitoring Data Of Stratum Deformation And Groundwater Level Regime, Kong Xiangru

Coal Geology & Exploration

Land subsidence is usually caused by over-exploitation of groundwater, and its occurrence and development have a certain lag relative to the change in groundwater level. Obtaining the accurate lag time of land subsidence has always been an important topic in land subsidence research. Based on the layered monitoring data of the long-time series of land subsidence and groundwater level regime from 2008 to 2018 by Land Subsidence Monitoring Station in Pinggezhuang, Beijing, the lag effect between stratum deformation in layers at different depths and groundwater level regime is analyzed in this paper by adopting methods of Mann Kendall trend test, …

Sequence-Paleogeography And Coal Accumulation Of The Paleogene Hunchun Formation In The Hunchun Basin, Hou Haihai, Li Qiangqiang, Shao Longyi, Fan Xuejie, Liang Guodong, Li Yanan

Coal Geology & Exploration

The Hunchun Basin is an important coal-bearing region in Jilin Province, northeastern China. The analysis of the sedimentary paleogeography of the Paleogene Hunchun Formation and coal-accumulation law in the sequence framework provides a theoretical basis for future coal and coalbed methane exploration. The lithofacies, sedimentary systems, sequence paleogeography, and coal accumulation characteristics were analyzed based on regional geology, drilling cores and well logging data. The results show five rock types, including gravel, sandstone, siltstone, mudstone, and combustible organic rock, and twelve lithofacies. The Hunchun Formation was divided into three third-order sequences by three sequence interfaces, including the regional unconformity surface, …

Recognition Of Land Use On Open-Pit Coal Mining Area Based On Deeplabv3+ And Gf-2 High-Resolution Images, Zhang Chengye, Li Feiyue, Li Jun, Xing Jianghe, Yang Jinzhong, Guo Junting, Du Shouhang

Coal Geology & Exploration

A highly efficient means is provided by remote sensing and deep learning to keep tracking of land use in open-pit coal mining area. Based on the high–resolution images from the domestic GF-2 satellite, a DeepLabv3+ model was utilized to achieve recognition of land use on open-pit coal mining area. In addition, a comparison was made among Deeplabv3+, U-Net, FCN, Random Forest, Support Vector Machine, and Maximum Likelihood Method. Firstly, samples data from high-resolution images were produced and sensitivity tests were conducted to determine the optimal cutting size and mode of the sample. Then, the deep neural network model (DeepLabv3+) was …

Transport Mechanism Of Ammonia Nitrogen In The Simulated Gob Area Packed With Coal Gangue, Li Yusong, Lu Yucan, Cao Qiong, Zhao Li, Zhu Kaipeng, Zhang Qing, Yu Hongfei, Zhang Lei

Coal Geology & Exploration

In many coal mining areas in western China, waste water produced during coal mining is often dominant in mine water, resulting in high ammonia nitrogen content. The pretreatment of mine water by filling gangue in coal mine gob areas has become an important measure for the resource utilization of mine water and gangue. The research took the coal gangue from Baode Coal Mine of Shenhua Shendong Coal Group Corporation as the filling medium and the ammonia nitrogen in mine water as the research object. Based on CXTFIT2.1, column simulation experiments were carried out to study the migration mechanism of ammonia …

Research On Interpolation Error Analysis Of Geological Modeling Of Intelligent Working Face, An Lin, Han Baoshan, Li Peng, Dai Zhenhua, Wang Xinmiao

Coal Geology & Exploration

Working face modeling generally obtains the actual distribution of the working face through detection methods such as three-dimensional seismic, tunnel and borehole surveys, and then it establishes the corresponding model using interpolation algorithms. During the modeling process, sampling data are the foundation and interpolation is the necessary way to realize the working face model. The interpolation algorithm and the amount of sampled data affect the accuracy of the face model to varying degrees. Quantitative research on the factors affecting the accuracy of the face model will provide important reference value for the optimization of the interpolation algorithm and the amount …

Effect Of Kaolin On Biogenic Coalbed Methane Production And The Response Of Microbial Community, He Huan, Huang Xinying, Huang Zaixing, Zhang Qian, Chen Zihao, Zhao Han, Ren Hengxing, Huang Guanhua

Coal Geology & Exploration

Kaolin is a common inorganic mineral in nature, which can promote the growth and metabolism of microorganisms. There is a large amount of kaolin in coal, however, there are few reports about its bio-gas production of coal. In order to investigate the effect of kaolin on biogas production, the coal obtained from Yulin, Shaanxi Province was taken as the research object, domesticated microorganisms were taken as the research flora, and different qualities of kaolin were added into the culture media to make biological simulation of gas production. The changes of CH₄ content, volatile fatty acids (VFAs) concentration, coenzyme F …

Numerical Simulation Of Gas Production For Multilayer Drainage Coalbed Methane Vertical Wells In Southern Qinshui Basin, Liu Shiqi, Fang Huihuang, Sang Shuxun, Hu Qiujia, Duan Weiying, Jia Huimin, Mao Chonghao

Coal Geology & Exploration

With the development of CBM (coalbed methane) exploitation, multilayer drainage of the CBM well has received wide attention. The production control technology is the key to ensure high and stable gas production of CBM well multilayer drainage. However, the complex geological conditions of multiple coal seams increase the difficulty of production control of multilayer drainage. Numerical simulation technology is an effective method to study the production control technology of CBM well multilayer drainage. The scientific and reliable simulation results can provide a basis for production control. In this study, considering the influence of temperature effect, shrinkage effect of coal matrix, …

Mesoscopic Law Of Stress And Fracture Evolution Of Coal Seams Hydraulic Fracturing, Li Quangui, Deng Yize, Hu Qianting, Zhang Yuebing, Song Mingyang, Liu Jichuan, Shi Jialin

Coal Geology & Exploration

Hydraulic fracturing is a technology to increase coal seam permeability, and its stress evolution characteristics and the judgment of fracture morphology and propagation range are particularly important. In this paper, based on directional fracturing, a fluid-structure coupling model of hydraulic fracturing is established by using the discrete element numerical method. The effects of fracturing flow, Poisson’s ratio, natural fracture density on stress evolution and fracture evolution, and their mesoscopic laws are investigated by means of the stress path and crack hot spot diagram. The results show that the stress evolution direction and the final stress path curve shape are obviously …

Stress Sensitivity Characteristics Of Deep Coal Reservoirs And Its Influence On Coalbed Methane Productivity, Liu Shunxi, Fan Kunyu, Jin Yi, Yu Zhenfeng, Dong Jiabin, Wang Changzheng

Coal Geology & Exploration

Deep coal reservoirs are in a high in-situ stress environment, and their permeability change characteristics are quite different from those of shallow ones. In order to study the effect of the effective stress on the permeability difference of deep coal reservoirs and the characteristics of stress sensitivity anisotropy, the samples from 1 200 m to 1 700 m of the No.15 coal seam in the Hengling block in the Qinshui Basin are taken as the research objects. The overburden porosity and permeability experiments are used to study the permeability changes of parallel and vertical bedding samples under different effective stress …