International Journal of Clean Coal and Energy

Journal Information
ISSN / EISSN : 2168-152X / 2168-1538
Published by: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 56
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SHERPA/ROMEO
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André Ndecky, Pierre W. Tavares, Aliou Senghor, Moustapha Kane, Hawa Ndiath, Issakha Youm
International Journal of Clean Coal and Energy, Volume 11, pp 1-12; https://doi.org/10.4236/ijcce.2022.111001

Abstract:
A number of persistent problems have been associated with the supply of traditional domestic fuels in developing countries and particularly in rural areas, including deforestation, scarcity of fuel wood and the high cost of fossil fuels. The use of biomass fuels derived from agricultural waste biomass, generally available in large quantities, has been advocated. This article, therefore, presents some bio-fuels in use or in acceptability test phase in some countries of West Africa and particularly in Senegal but also their characteristics, compared to those of wood or wood charcoal. Samples were prepared and analyzed for moisture content, ash content, volatiles mater, fixed carbon and calorific value. The results indicate that charcoal and bio-charcoal (not mixed with clay) have the best calorific value, while pellets and typha briquettes have the best results in volatile matter and fixed carbon. The results of moisture are generally satisfactory against the use of clay as a binder detrimental to fuel performance. These results suggest that pellets and bio-fuels are used as an energy source for domestic purposes; that the binder is changed in others; pelletizing and briquetting transformations are expanded in other residues such as rice husks, peanut shells.
Peng Gong
International Journal of Clean Coal and Energy, Volume 11, pp 13-23; https://doi.org/10.4236/ijcce.2022.112002

Abstract:
In coal-fired power generation industry, parameters such as particle size affect combustion efficiency. Especially in the application of two-phase flow clean energy, the parameters such as particle velocity, particle size distribution and concentration are very important, because the coal particle velocity, concentration or size range have an impact on the whole combustion process. This paper introduces an optical measurement setup based on the transmission fluctuation correlation spectrum measurement technique, which realizes the simultaneous measurement of particle velocity, particle size distribution and concentration. Compared with image method, ultrasonic spectrum method and other methods, the experimental device is simple and low-cost.
Ayoola Y. Jimoh, Olusola J. Ojo
International Journal of Clean Coal and Energy, Volume 10, pp 1-19; https://doi.org/10.4236/ijcce.2021.101001

Abstract:
The Benue Trough has been known to have great potential for resources such as coal, hydrocarbon, limestone, barite, gypsum, etc. The study area is Maiganga coal mine located at Gombe, Gongola Basin, northern Benue Trough in northeast Nigeria. Two coal seams, shales, siltstones, sandstones, and intercalation of ironstones make up the stratigraphic succession of 35 m thick. The coal is currently being exploited as a source of fuel at the Ashaka Cement Factory, Ashaka, Gombe state. Elemental and proximate analyses of the coal samples were carried out to investigate coking potential, acid generation potential and its suitability as a source of fuel. The paleodepositional condition and the original plant that form the coal were also examined. The proximate analysis showed that the moisture content ranges from 9.55% - 11.13%, volatile matter (40.88% - 44.89% dry), ash (5.29% - 13.99% dry), fixed carbon (41.30% - 53.41% dry) and calorific value (5469 - 6452 kcal/kg). Average values of the major elements; K2O, MgO and Fe2O3 are low but a high loss on ignition was obtained for the coal ash. The samples recorded low concentrations in the trace elements, except for Ni, Cu, Ba, Sr, and Zr. Coal seam A exhibits negative europium anomaly and positive cerium anomaly indicating peat vegetation (Sphagnum L.) while coal Seam B showed negative cerium anomaly indicating soil grown plants (Mangrove and Vicia villossa). The present investigation showed that the coals were deposited in fluvial to paralic environments. The coals are not suitable for coking but have potential as a source of fuel and power generation.
Editha M. Ndunguru
International Journal of Clean Coal and Energy, Volume 10, pp 41-58; https://doi.org/10.4236/ijcce.2021.103003

Abstract:
The majority of the population in developing countries have limited access to clean energy. To increase access to clean energy, the governments and other stakeholders have been working hard to create enabling environments for their adoption and utilization. For the household cooking sector, technological innovations such as improved biomass fuels, improved biomass cookstove, solar cooking, biogas and recently bottled gas service have been or are being deployed to scale up clean cooking. Nevertheless, a good number of the innovations intended for upscaling clean cooking in developing countries have failed to meet the desired goals due to limited support from the national governments or the international community. Pay-Go is among the recent innovations in the East African region intended for promoting the use of bottled gas (liquefied petroleum gas-LPG). This study evaluates the practicality of Pay-Go innovation on bottled gas, popularly known as Pay-as-you-Cook. Specifically, the article examines the evolution of Pay-as-you-Cook, its execution, usefulness and challenges; and its implications on household energy sector development. The study was conducted in Kinondoni Municipality, Dar es Salaam, Tanzania between 2018 and 2020. The study used both qualitative and quantitative approaches. Purposive and non-random sampling techniques were used in selecting respondents. Purposive sampling was used to identify key informants while snowball sampling was used to find household respondents. Information was gathered from KopaGas (Pay-as-you-Cook innovator) headquarter-Kinondoni Morocco; and from Pay-as-you-Cook clients in Kinondoni Moscow, Mkwajuni and Hananasif. Methods of data collection involved semi-structured interviews and observation. Instruments of data collection included interview guides and observation checklists. Data analysis was accomplished with Nvivo 12. Findings show that Pay-as-you-Cook innovation was intended for promoting bottled gas adoption mainly to low-income households. The innovation was discovered to be convenient to many low- income households as it enabled them to use bottled gas for cooking without necessarily climbing the economic ladder. Yet, the innovation presents several challenges which are doubtful to its practicality.
Adnan Ibrahim, , Yiran Jiang, Ali Riaz, Farrukh Saleem, Yifang Dong, Lei Jia, Panpan Zhao
International Journal of Clean Coal and Energy, Volume 10, pp 21-40; https://doi.org/10.4236/ijcce.2021.102002

Abstract:
The heat transfer of supercritical fluids is a vastly growing field, specifically to find suitable alternatives to replace conventional R134a, which can be beneficial for climate change. Most of the experimental and numerical investigations have been conducted to explore supercritical water, carbon dioxide and R134a as heat transfer working fluids. Hydrofluoroolefin (HFO) and refrigerants blends have been considered the most environment-friendly refrigerants to replace Chlorofluorocarbons (CFCs), Hydrochlorofluoro-carbons (HCFCs) and Hydrofluorocarbons (HFCs). Their main advantage of zero Ozone Depletion Potential (ODP) and comparatively lower Global Warming Potential (GWP) have attracted growing amount of attention to mitigate environmental issues. This work adopts the computational method and takes the environmentally friendly refrigerants to investigate the heat transfer characteristics under widely used shear-stress transport (SST) model. A comprehensive comparison was performed at reduced pressure of 1.10 for supercritical fluids R515A, R1234ze(E) and R134a. The peaks of heat transfer coefficient occurred in the vicinity of pseudo critical temperature for all of these considered fluids; however, R134a resulted in higher heat transfer coefficient, Reynolds number and Prandtl number in comparison with R515A and R1234ze(E). The higher heat transfer coefficient of supercritical fluid R134a is owing to its thermophysical properties and the specific heat plays crucial role in the heat transfer of supercritical fluids. Owing to environmental issues, R515A can be a considerable replacement of R134a. R1234ze(E) is also promising alternative to R134a; however, safety issues should thoroughly concern its mild flammable characteristics.
P. W. Tavares, H. D. Ndiath, M. Kâne, B. Mbow, A. T. Niang, I. Youm
International Journal of Clean Coal and Energy, Volume 09, pp 1-14; https://doi.org/10.4236/ijcce.2020.91001

Abstract:
This document presents the evaluation and the monitoring of the performances of the first grid-connected photovoltaic system installed in the Center of Studies and Researches on the Renewable Energies (CERER) inaugurated on December 4th, 2012 by the governmental authorities of Senegal and Tenerife. This mini power plant of 3.15 kWc is a perfect example of the political will of the government which is to reduce the production cost of the electricity, with the diversification of the sources of production, and the greater use of the other sources such as the natural gas, the coal, the renewable energies. The evaluation of the performances of the installation is realized by using the indicators of efficiency and performance as the photovoltaic surface yield, the ratio of photovoltaic performance, the photovoltaic specific yield, and the losses of captures. The obtained results show that a big part of the energy shone during the period of observation was not able to be used further to circumstances such as the losses of conductivity, the heat losses or for example the defects on components. The analysis also shows that a large part of the produced energy is not injected because of the dilapidation of the network, the defects of landing but especially one disjunction sees frequently at the level of the point of injection.
Xueyi Zhu, Liangfeng Zhu
International Journal of Clean Coal and Energy, Volume 09, pp 15-25; https://doi.org/10.4236/ijcce.2020.92002

Abstract:
In recent years, the Chinese government has asked enterprises to follow the path of “green development”. This requirement naturally becomes the guiding ideology of coal resource capitalization theory. this paper focuses on the core contents of the green development of coal resource capitalization, and uses the software of ROSTCM6 and UCINET to construct six frameworks of the green theory of coal resource capitalization with the method of “Condensed Subgroup”: the basic theory of capitalization, the conservation theory of capitalization, the environmental protection theory of capitalization, the harmonious coexistence theory of capitalization, the mainline development theory of ecological industry of capitalization Industrial theory, benign cycle sustainable development theory of capitalization, the paper further designs the outline content of the framework.
Olawale O. Olanrewaju, Obafemi O. Olubanjo
International Journal of Clean Coal and Energy, Volume 08, pp 15-31; https://doi.org/10.4236/ijcce.2019.82002

Abstract:
The overdependence on crude oil in African countries warrants the need for alternative sources of energy. A 56-litre-capacity biogas digester was designed, fabricated and evaluated. Investigations were made into the production of biogas from the mixture of cow dung, swine dung and poultry dropping. Standard equations and models were used in the design of the components of the manually operated digester. The digester temperature, ambient temperature and pH were monitored during the experiment. The proximate analysis showed that volatile solid, total solid and moisture content for the mixed substrates at the initial stage were: 64.7%, 83.5% and 13.5% respectively. Similarly, at the digestion stage, the volatile solid, total solid and moisture content were: 54.1%, 22.6% and 74.4% respectively. Advancement of decomposition leads to gradual increasing pH value from 7.2 to 7.4, which indicates the stability of organic matter. The moisture content on a wet basis was initially 13.5%. This value latter increased to 74.4%. On the average, 15 kg of mixed substrates with 25 litres of impure water produced biogas within 25 days of digestion. The gas produced from mixed substrates became flammable with blue flame after 16 days of production, indicating that the ratio of methane gas generated with the three mixtures of fresh animal waste was higher than other gases produced.
Weiguo Zhang, Jianye Yang, Yuan Shi, Tingting Lv, Mengmeng Fan
International Journal of Clean Coal and Energy, Volume 08, pp 1-13; https://doi.org/10.4236/ijcce.2019.81001

Abstract:
Stone coal is a special resource, because it is associated with a variety of rare metal elements. The elemental geochemical characteristics of stone coal can provide useful information for the study of its formation and evolution history. The content of rare earth elements in stone coal has been the focus of attention. Stone coal is widely distributed in southern Shaanxi province of China. In order to study the content and distribution of rare earth elements in stone coal, and provide a plan for the comprehensive development and utilization of stone coal, this study tested the rare earth elements content of stone coal, parting and coal ash samples, respectively, compared the content of rare earth elements in stone coal, parting, coal ash with the mean value of China coal, the mean value of world coal and the abundance value of upper crust, and discussed the features of rare earth elements content in different types of samples in southern Shaanxi province of China. The average contents of rare earth elements in the samples of stone coal, parting and coal ash were calculated, and the enrichment coefficients of the samples with the mean value of China coal, the mean value of world coal and the abundance value of upper crust were listed. The distribution rules and characteristics of the contents of rare earth elements in different types of samples in southern Shaanxi province of China were summarized.
André Ndécky, Sébastien Gamache, Fabé I. Barro, Issakha Youm
International Journal of Clean Coal and Energy, Volume 07, pp 39-57; https://doi.org/10.4236/ijcce.2018.73003

Abstract:
The Design of Experiments (DOE) and the Analysis of Variance (ANOVA) are used to determine the effect of fuel type, fuel initial load, secondary air inlet and ventilation on thermal efficiency and CO emission of two biomass fire cookstoves during boiling or simmering. Analysis of variance with Fischer’s statistical test (F-test) and Newman-Keuls test were applied to establish the influence of the independent parameters on the studied responses. The results of this study are useful to application of charcoal cooks stoves.
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