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Francis Chinweuba, EbohORCID iD iconorcid.org/0000-0001-7478-3480
Publications (4 of 4) Show all publications
Eboh, F. C., Ahlström, P. & Richards, T. (2017). Exergy Analysis of Solid Fuel-Fired Heat and Power Plants: A Review. Energies
Open this publication in new window or tab >>Exergy Analysis of Solid Fuel-Fired Heat and Power Plants: A Review
2017 (English)In: Energies, ISSN 1996-1073, E-ISSN 1996-1073Article in journal (Refereed) Published
Abstract [en]

The growing demand for energy is particularly important to engineers with respect to how the energy produced by heat and power plants can be used efficiently. Formerly, performance evaluation of thermal power plants was done through energy analysis. However, the energy method does not account for irreversibilities within the system. An effective method to measure and improve efficiency of thermal power plant is exergy analysis. Exergy analysis is used to evaluate the performance of a system and its main advantage is enhancement of the energy conversion process. It helps identify the main points of exergy destruction, the quantity and causes of this destruction, as well as show which areas in the system and components have potential for improvements. The current study is a comprehensive review of exergy analyses applied in the solid fuels heat and power sector, which includes coal, biomass and a combination of these feedstocks as fuels. The methods for the evaluation of the exergy efficiency and the exergy destruction are surveyed in each part of the plant. The current review is expected to advance understanding of exergy analysis and its usefulness in the energy and power sectors: it will assist in the performance assessment, analysis, optimization and cost effectiveness of the design of heat and power plant systems in these sectors.

Place, publisher, year, edition, pages
Basel, Switzerland: MDPI, 2017
Keywords
exergy, heat and power, solid fuels, system efficiencies
National Category
Engineering and Technology Energy Engineering
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-11885 (URN)10.3390/en10020165 (DOI)000395469200019 ()2-s2.0-85014124644 (Scopus ID)
Available from: 2017-02-02 Created: 2017-02-02 Last updated: 2018-11-29Bibliographically approved
Eboh, F. C., Ahlström, P. & Richards, T. (2016). Estimating the specific chemical exergy of municipal solid waste. Energy Science & Engineering, 4(3), 217-231
Open this publication in new window or tab >>Estimating the specific chemical exergy of municipal solid waste
2016 (English)In: Energy Science & Engineering, ISSN 2050-0505, Vol. 4, no 3, p. 217-231Article in journal (Refereed) Published
National Category
Energy Engineering
Identifiers
urn:nbn:se:hb:diva-10793 (URN)10.1002/ese3.121 (DOI)000377213700005 ()2-s2.0-85014098626 (Scopus ID)
Available from: 2016-09-28 Created: 2016-09-28 Last updated: 2018-11-29Bibliographically approved
Eboh, F. C., Ahlström, P. & Richards, T. (2016). Estimating the specific exergy of municipal solid waste. Energy Science & Engineering, 4(3), 217-231
Open this publication in new window or tab >>Estimating the specific exergy of municipal solid waste
2016 (English)In: Energy Science & Engineering, ISSN 2050-0505, Vol. 4, no 3, p. 217-231Article in journal (Refereed) Published
Abstract [en]

A new model for predicting the specific chemical exergy of municipal solid waste (MSW) is presented; the model is based on the content of carbon, hydrogen, oxygen, nitrogen, sulfur, and chlorine on a dry ash-free basis (daf). The proposed model was obtained from estimations of the higher heating value (HHV) and standard entropy of MSW using statistical analysis. The ultimate analysis of 56 different parts of MSW was used for the derivation of the HHV expression. In addition, 30 extra parts were used for validation. One hundred and seventeen relevant organic substances that represented the main constituents in MSW were used for derivation of the standard entropy of solid waste. The substances were divided into different waste fractions, and the standard entropies of each waste fraction and for the complete mixture were calculated. The specific chemical exergy of inorganic matter in the waste was also investigated by considering the inorganic compounds in the ash. However, as a result of the extremely low value calculated, the exergy of inorganic matter was ignored. The results obtained from the HHV model show a good correlation with the measured values and are comparable with other recent and previous models. The correlation of the standard entropy of the complete waste mixture is less accurate than the correlations of each individual waste fraction. However, the correlations give similar results for the specific chemical exergy, indicating that HHV has a greater impact when estimating the specific exergy of solid waste than entropy.

Place, publisher, year, edition, pages
John Wiley & Sons, 2016
National Category
Energy Engineering
Research subject
Resource Recovery
Identifiers
urn:nbn:se:hb:diva-11085 (URN)10.1002/ese3.121 (DOI)000377213700005 ()2-s2.0-85014098626 (Scopus ID)
Available from: 2016-10-26 Created: 2016-10-26 Last updated: 2018-11-29Bibliographically approved
Eboh, F. C., Ahlström, P. & Richards, T. (2016). Method of Estimating Absolute Entropy of Municipal Solid Waste. World Academy of Science, Engineering and Technology, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, 10(7), 689-694
Open this publication in new window or tab >>Method of Estimating Absolute Entropy of Municipal Solid Waste
2016 (English)In: World Academy of Science, Engineering and Technology, International Journal of Environmental, Chemical, Ecological, Geological and Geophysical Engineering, E-ISSN 2010-3778, Vol. 10, no 7, p. 689-694Article in journal (Refereed) Published
Abstract [en]

Entropy, as an outcome of the second law of thermodynamics, measures the level of irreversibility associated with any process. The identification and reduction of irreversibility in the energy conversion process helps to improve the efficiency of the system. The entropy of pure substances known as absolute entropy is determined at an absolute reference point and is useful in the thermodynamic analysis of chemical reactions; however, municipal solid waste (MSW) is a structurally complicated material with unknown absolute entropy. In this work, an empirical model to calculate the absolute entropy of MSW based on the content of carbon, hydrogen, oxygen, nitrogen, sulphur, and chlorine on a dry ash free basis (daf) is presented. The proposed model was derived from 117 relevant organic substances which represent the main constituents in MSW with known standard entropies using statistical analysis. The substances were divided into different waste fractions; namely, food, wood/paper, textiles/rubber and plastics waste and the standard entropies of each waste fraction and for the complete mixture were calculated. The correlation of the standard entropy of the complete waste mixture derived was found to be somsw= 0.0101C + 0.0630H + 0.0106O + 0.0108N + 0.0155S + 0.0084Cl (kJ.K-1.kg) and the present correlation can be used for estimating the absolute entropy of MSW by using the elemental compositions of the fuel within the range of 10.3%  C 95.1%, 0.0%  H  14.3%, 0.0%  O  71.1%, 0.0  N  66.7%, 0.0%  S  42.1%, 0.0%  Cl  89.7%. The model is also applicable for the efficient modelling of a combustion system in a waste-to-energy plant.

Keywords
Absolute entropy, irreversibility, municipal solid waste, waste-to-energy
National Category
Energy Engineering
Identifiers
urn:nbn:se:hb:diva-10794 (URN)
Available from: 2016-09-28 Created: 2016-09-28 Last updated: 2017-05-04Bibliographically approved
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