检索结果-南通市图书馆

A review of research on spontaneous combustion of coal

在线全文

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2020年第3期30卷 303-311页

作者： m.onifade B.Genc Department for management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityVietnam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh CityVietnam The School of mining Engineering University of the WitwatersrandSouth Africa

Coal oxidation at low temperatures is the heat source liable for the self-heating and spontaneous combustion of coal. This phenomenon has imposed severe problems in coal related industries. Attempts to understand this phenomenon by previous researchers have provided significant progress. It is wellknown that coal oxidation at low temperatures involves oxygen consumption and formation of gaseous and solid oxidation products. This process is majorly influenced by temperature, oxidation history of coal,coal properties, particle size distribution of the coal, etc. The current understanding of the phenomenon of self-heating and spontaneous combustion of coal is discussed along with the different experimental and numerical models established to predict self-heating characteristics of coal. This paper focuses on the global position of the study carried out by academics, research institutes and industries on spontaneous combustion of coal and coal mine fires. Within this framework, the generally used spontaneous combustion techniques to predict the spontaneous combustion liability of coal were evaluated. These techniques are well-known in their usage, but no specific method has become a standard to predict the spontaneous combustion liability. Further study is still needed to indicate a number of impending issues and to obtain a more complete understanding on the phenomenon.

关键词： Coalfields Experimental Numerical Propensity Self-heat Statistical method

A new apparatus to establish the spontaneous combustion propensity of coals and coal-shales

在线全文

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2018年第4期28卷 643-649页

作者： m.onifade B.Genc A.Carpede School of mining Engineering University of the Witwatersrand

Coal and coal-shale both tend to undergo spontaneous combustion under favourable atmospheric conditions. The Wits-Ehac index has been developed in South Africa since the late 1980's to test the spontaneous combustion liability of coal. However, in some cases, the Wits-Ehac index fails to produce tangible results when testing coal-shales. To overcome this problem, a new apparatus has been developed to test carbonaceous materials such as coal and coal-shale under chemical reactions with oxygen and an index has been obtained. This index is called the Wits-CT index. The equipment emulates the influence of oxygen adsorption on carbonaceous material for a period of 24 h without a heating *** Wits-CT index uses the total carbon content of the sample and the temperature variations obtained from the samples during reaction with oxygen to predict the spontaneous combustion liability. Eighteen samples have been analyzed using both indices and the results are in-line. It was found that coals and coal-shales with higher values of the Wits-CT index are more liable to spontaneous *** research on different coal-shales is underway in order to establish an extensive database for coal and coal-shales, together with known incidences of self-heating.

关键词： Coal Coal-shale Spontaneous combustion Wits-Ehac index Wits-CT index

Influence of organic and inorganic properties of coal-shale on spontaneous combustion liability

在线全文

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2019年第6期29卷 851-857页

作者： m.onifade B.Genc N.Wagner The School of mining Engineering University of the WitwatersrandJohannesburg 2050South Africa Department of Geology University of JohannesburgJohannesburg 2092South Africa

Coal and coal-shale undergo low-temperature oxidation when exposed to air,potentially leading to spontaneous ***-shale found in association with coal seams vary considerably in their intrinsic properties and spontaneous combustion liability *** coal-shale samples collected from four different coal mines in Witbank Coalfield,South Africa,were experimentally *** influence of coal-shale intrinsic properties and spontaneous combustion liability indices(determined by the WitsEhac Index and the Wits-CT Index)were *** liability indices indicate relationships with the intrinsic factors and thus,identifying the major intrinsic factors affecting liability toward spontaneous combustion in these coal-shale *** XRF analysis indicated that the coal-shale samples are rich in Si O2,Al2O3 and Fe2O3,while the XRD showed that same coal-shale samples are generally dominated with kaolinite and *** coal-shale occurred in association with medium Rank C bituminous coal and contained varying proportion of *** Wits-Ehac Index was unable to reliably determine liability indices of some coal-shale samples,and hence the Wits-CT Index was *** results obtained from the characterisation tests may be used as a tool to predict the spontaneous combustion liability in carbonaceous material and may serve as a reference when comparing coal-shale from different coal mines.

关键词： Wits-Ehac Index Wits-CT Inde Witbank Coalfield and self-heating

Spontaneous combustion liability of coal and coal-shale: a review of prediction methods

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2019年第2期6卷 151-168页

作者： m.onifade B.Genc The School of mining Engineering University of the Witwatersrand P.O. WITS Johannesburg 2050 South Africa

This study presents a review of the various methods to predict the spontaneous combustion liability of coal and coal-shale. The relative propensity of coal to undergo self-heating can be established by different methods. These methods are well established in their usage, but the fact that no particular test method has become a standard to predict the spontaneous combustion liability indicates that doubt still exists as to the validity of all of them. The underlying principle of all the tests is that the more readily the coal undergoes exothermic oxidation, the more liable it is to self-heat. Comprehensive studies that centres on the international position on research being conducted by academics, different research institutes and industries on spontaneous combustion of coal and coal mine fires were evaluated. Relationships between the geochemical analysis (proximate and ultimate analysis, forms of sulphur, petrographic properties, X-ray diffraction and X-ray fluorescence) and spontaneous combustion testing methods (numerical and experimental approaches) used to predict the spontaneous combustion liability of coal were reviewed. The combination of these tests provides a better understanding of the mechanism that controls the spontaneous combustion phenomena. However, irrespective of the extensive studies that have been conducted over time, spontaneous combustion is still a major problem in the coal value chain.

关键词： Coalfields Spontaneous combustion liability macerals Numerical and geochemical analysis

Analysis of spontaneous combustion liability indices and coal recording standards/basis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2020年第5期30卷 723-736页

作者： A.R.Gbadamosi m.onifade B.Genc S.Rupprecht School of mining Metallurgy and Chemical EngineeringUniversity of JohannesburgSouth Africa Department for management of Science and Technology Development Ton Duc Thang UniversityHo Chi Minh CityViet Nam Faculty of Applied Sciences Ton Duc Thang UniversityHo Chi Minh CityViet Nam School of mining Engineering University of the WitwatersrandJohannesburgSouth Africa

The characterization of the physical and chemical properties of coal on a standard provides an understanding of its characteristics towards spontaneous *** trend of linear relationships between coal recording standards(%air-dried(ad),%dry(db)and%dry ash free(daf)basis)of 30 selected coal samples from the Witbank coalfields and spontaneous combustion liability indices were *** spontaneous combustion liability indices of these samples were evaluated by crossing point temperature(XPT),Stage II Slope,FCC(Feng,Chakravorty,Cochrane)and the Wits-Ehac tests,while the coal properties were determined from the proximate and ultimate *** results obtained from these coal properties were related to different liability indices to develop trends of linear relationships using regression *** ad basis indicated higher correlation coefficients than the db and daf basis for the XPT and FCC index,while the daf showed higher correlation coefficients than the ad and db basis for the Wits-Ehac *** was found that the trend of linear relationships of these coal properties differs from one liability index to the *** XPTs showed a better trend followed by the Stage II Slope on the coal properties among the spontaneous combustion liability indices evaluated.

关键词： Coal basis Correlation analysis Liability indices Spontaneous combustion

Development of multiple soft computing models for estimating organic and inorganic constituents in coal

在线全文

学校读者我要写书评

暂无评论

International Journal of mining Science and Technology 2021年第3期31卷 483-494页

作者： m.onifade A.I.Lawal J.Abdulsalam B.Genc S.Bada K.O.Said A.R.Gbadamosi Department of mining and metallurgical Engineering University of NamibiaWindhoekNamibia Department of mining Engineering Federal University of TechnologyAkureNigeria DSI/NRF Clean Coal Technology Research Group Faculty of Engineering and the Built EnvironmentUniversity of the Witwatersrand2050 JohannesburgSouth Africa The School of mining Engineering University of the Witwatersrand2050 JohannesburgSouth Africa mining and mineral Processing Engineering Department Taita Taveta UniversityVoiKenya School of mining Metallurgy and Chemical EngineeringUniversity of Johannesburg2006 JohannesburgSouth Africa

The distribution of the various organic and inorganic constituents and their influences on the combustion of coal has been comprehensively ***,the combustion characteristics of pulverized coal depend not only on rank but also on the composition,distribution,and combination of the *** the proximate and ultimate analyses,determining the macerals in coal involves the use of sophisticated microscopic instrumentation and *** this study,an attempt was made to predict the amount of macerals(vitrinite,inertinite,and liptinite)and total mineral matter from the Witbank Coalfields samples using the multiple input single output white-box artificial neural network(mISOWB-ANN),gene expression programming(GEP),multiple linear regression(mLR),and multiple nonlinear regression(mNLR).The predictive models obtained from the multiple soft computing models adopted are contrasted with one another using difference,efficiency,and composite statistical indicators to examine the appropriateness of the *** mISOWB-ANN provides a more reliable predictive model than the other three models with the lowest difference and highest efficiency and composite statistical indicators.

关键词： multiple soft computing models Coal Organic and inorganic constituents

modelling spontaneous combustion liability of carbonaceous materials

在线全文

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2018年第2期5卷 191-212页

作者： m. onifade B. Genc The School of mining Engineering University of the Witwatersrand Johannesburg 2050 South Africa

This paper presents predictive models to determine spontaneous combustion liability of carbonaceous materials （coals and coal-shales） using statistical analysis. The intrinsic properties and spontaneous combustion liability index were determined by testing 14 coals and 14 coal-shales from Witbank coalfields, South Africa. The relationship between these intrinsic properties （obtained from proximate, ultimate and petrographic analysis） and spontaneous combustion liability indices （the Wits-Ehac Index and Wits-CT Index） were established. The influence of the intrinsic properties of coal-shales in relation to coal properties affecting spontaneous combustion has been established using a statistical method. The linear regression analysis indicates better linear relationships between some of the selected intrinsic properties and spontaneous combustion liability index and thus, identifies the major intrinsic factors affecting their liability toward spontaneous combustion. It was found that a definite positive or negative correlation coefficient exists between the intrinsic factors and spontaneous combustion liability. A set of models to predict the spontaneous combustion liability was derived. The best significant correlation along with the most appropriate model as indicated by R-squared values, the coefficient of corre- lations and standard error was used to predict the incident of spontaneous combustion.

关键词： Coals Coal-shales Statistical analysis Wits-Ehac Index Wits-CT Index Spontaneous combustion

Comparative analysis of coal and coal-shale intrinsic factors affecting spontaneous combustion

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2018年第3期5卷 282-294页

作者： m. onifade B. Genc The School of mining Engineering University of the Witwatersrand P.O. WITS Johannesburg 2050 South Africa

Coal and coal-shales tend to undergo spontaneous combustion under favourable atmospheric conditions. Spontaneous combustion liability index and intrinsic properties of coals and coal-shales varies between （above and below） coal seams. The spontaneous combustion liability index （obtained from the Wits-Ehac Index） and intrinsic properties （obtained from proximate, ultimate, and petrographic analysis） of fourteen samples representative of in situ coal （bituminous） and fourteen coal-shales obtained in Witbank coalfield, South Africa were experimentally studied. Comparative analysis of the relationships between the spontaneous combustion liability index and intrinsic properties of coals and coalshales were established to evaluate their effects on self-heating potential. The intrinsic properties show linear relationship with spontaneous combustion liability and therefore, identifies the factors affecting spontaneous combustion of these materials. The influence of coal-shales intrinsic properties towards spontaneous combustion liability shows higher correlation coefficients than the coals. Both coals and coal-shales show inertinite maceral as major constituents than the vitrinite and liptinite macerals, hence the reactivity of inertinite macerals may show greater influence on spontaneous combustion liability. A definite positive or negative trends exists between the intrinsic properties and spontaneous combustion liability index. This research is part of a larger project which is considering the influence of intrinsic properties of coals and coal-shales on spontaneous combustion liability.

关键词： Coal-shales Spontaneous combustion Liability index Statistical analysis and correlation coefficient

Folic Acid Supplementation Ameliorates Inflammation and Apoptosis in Ethanol-Induced Gastric Ulceration in Rats

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Biosciences and medicines 2017年第12期5卷 101-117页

作者： K. O. Ajeigbe L. E. Jaja A. A. onifade P. O. Obabueki W. m. Owonikoko School of Basic medical Sciences Igbinedion University Okada Nigeria College of medicine University of Ibadan Ibadan Nigeria

Although the gastroprotective potential of folic acid has been reported, little is known about the role of inflammation and apoptosis in the said activity. This study, therefore, assessed lipid peroxidation (LPO), Neutrophil-lymphocyte ratio (NLR), C-reactive protein (CRP) as markers of inflammation and, p53 and BCl-2 as markers of apoptosis in ethanol-induced gastric ulcer pretreated with Folic acid (FA) for twenty-one (21) days. Adult male Wistar rats were arranged into experimental groups (n = 5) viz: 1) Control;2) Ulcer control;3) 2FA (2 mg/kg folic acid + Ulcer);4) 3FA (3 mg/kg folic acid + Ulcer);5) OmEP (20 mg/kg omeprazole + Ulcer);6) 2FA + OmEP + Ulcer;and 7) 3FA + OmEP + Ulcer. Ulcer score, LPO, NLR, serum CRP were all determined one hour post ulcer induction. Paraffin gastric sections were stained first with H & E, then immunostained for p53 and BCl-2. Ethanol caused gastric lesion with an index of 3.0 ± 0.2. Ulcer severity and LPO was significantly decreased in the 2FA, 3FA, OmEP, 2FA + OmEP and 3FA + OmEP groups. NLR reduced significantly in the 2FA, 3FA, OmEP and OmEP + 3FA group. Qualitatively, there was absence of C-reactive protein in the 2FA group while quantitatively, presence of CRP appeared sustained in the 3FA and OmEP treated groups. Unlike p53, the expression and labeling index of BCl-2 were significantly enhanced more in the FA and OmEP combination than OmEP alone. Folic acid ameliorates the development of gastric ulcer in rats via its anti-inflammatory and anti-apoptotic activities.

关键词： Folic Acid Lipid Peroxidation (LPO) Neutrophil-Lymphocyte Ratio (NLR)