Techno-economic analysis of electricity and heat production by co-gasification of coal, biomass and waste tyre in South Africa

Abstract: South Africa has large deposit of coal that supports about 95 % of electric power generation in the country. The fuel is fast depleting, though the current reserve may serve for the next century. However, the emissions from the coal projects huge threat to the environment. Similarly, the country has abundant solid wastes that can be co-gasified with coal to H2 enriched syngas for clean energy production. A 5 MW combined heat and power plant was studied using different coal-to-solid waste ratios including 1:1, 3:2, and 4:1 with feedstocks costing, and without feedstock costing. The lower heating value of the fuels, determined from a model equation was applied to estimate the annual feedstocks requirement and the feed rate..

Prediction of emissions and profits from a biomass, tyre, and coal fired co-gasification CHP plant using artificial neural network: Nigerian and South African perspectives

Abstract : The local sourcing of feedstock for energy generation will reduce costs in the power plant, and promote energy sustainability. Most times, potential investors in this area show interest about understanding the profitability of the business because, the information boosts the confidence of the investors in the project, and gives them the opportunity of making a short and long term plans about the business. The emissions arising from the energy plant is an important aspect of the venture that requires proper attention, otherwise the costs of emission control may consume a greater part of the profit, hence rendering the business un-viable. Nigeria and South Africa (SA) have abundant biomass (e.g. corn cob, sugarcane bagasse, & pine saw dust) coal and tyre that can be used as fuel in an energy plant. A 10 MW CHP plant was fired with coal and biomass, and tyre obtained from Nigeria and South Africa (SA) respectively, at ratios of 1:1, 3:2, and 4:1 to study the emissions and profits in the plant. An empirical model was employed to estimate the annual amount of feedstock and feed rate required for the plant, after which, an artificial neural network (ANN); LevenbergMarquardt algorithm was used to predict the emissions and profits in the plant for 20-year- investment period with feedstock costing (WFC) and without feedstock costing (WOFC). The profit obtained from the South African feedstock, WFC and WOFC; produced about 45.18 % and 36.83 % ($3,900,000.07 and$3,179,184.49) higher profits than the Nigerian feedstock, but the CO, NOX, & SO2 emissions from Nigerian feedstock were lower than that of SA. The findings from this study could be used as a platform for decision making by potential investors and stake-holders, and further research and development in the area

Effect and optimization of process conditions during solvolysis and torrefaction of pine sawdust using the desirability function and genetic algorithm

Understanding optimal process conditions is an essential step in providing high-quality fuel for energy production, efficient energy generation, and plant development. Thus, the effect of process conditions such as the temperature, time, nitrogen-tosolid ratio (NSR), and liquid-to-solid ratio (LSR) on pretreated waste pine sawdust (PSD) via torrefaction and solvolysis is presented. The desirability function approach and genetic algorithm (GA) were used to optimize the processes. The response surface methodology (RSM) based on Box−Behnken design (BBD) was used to determine the effect of the process conditions mentioned above on the higher heating value (HHV), mass yield (MY), and energy enhancement factor (EEF) of biochar/hydrochar obtained from waste PSD. Seventeen experiments were designed each for torrefaction and solvolysis processes. The benchmarked process conditions were as follows: temperature, 200−300 °C; time, 30−120 min; NSR/LSR, 4−5. In this study, the operating temperature was the most influential variable that affected the pretreated fuel’s properties, with the NSR and LSR having the least effect. The oxygen-to-carbon content ratio and the HHV of the pretreated fuel sample were compared between the two pretreatment methods investigated. Solvolysis pretreatment showed a higher reduction in the oxygen-to-carbon content ratio of 47%, while 44% reduction was accounted for the torrefaction process. A higher mass loss and energy content were also obtained from solvolysis than the torrefaction process. From the optimization process results, the accuracy of the optimal process conditions was higher for GA (299 °C, 30.07 min, and 4.12 NSR for torrefaction and 295.10 °C, 50.85 min, and 4.55 LSR for solvolysis) than that of the desirability function based on RSM. The models developed were reliable for evaluating the operating process conditions of the methods studied.The Research and Innovation Support and Advancement and the National Research Foundation, South Africa (DST-NRF).http://pubs.acs.org/journal/acsodfam2022Chemical Engineerin

Potentials of torrefied pine sawdust as a renewable source of fuel for pyro-gasification : Nigerian and South African perspective

The impacts of fossil energy on the climate and environment emphasize the need for alternative energy resources. The use of waste wood is one such method to potentially reduce fossil-based energy dependence. However, raw biomass fuel properties are generally poor and unpredictable, thus requiring pretreatment to maximize their energy potentials for an efficient conversion to syngas via pyrogasification. Two species of pine sawdust (PSD) wastes generated in abundance from large-scale timber industries in Nigeria and South Africa were investigated for improvements in their fuel properties after torrefaction. Samples were torrefied under optimum conditions of 300 °C and 45 min. Different analytical procedures show that the higher heating value (HHV), enhancement factor, energy density, and solid yield of the Nigerian PSD exceeded those of their South African counterpart by 2.38, 5.37, 3.49, and 11.15%, respectively. The HHV of the torrefied fuels increased by 57.29 and 37.9% for the Nigerian and South African PSDs, respectively, when compared to the raw fuels. Also investigated were improvements in their H/C and O/C ratios and thermal degradation at varied heating rates.http://pubs.acs.org/journal/acsodfpm2021Chemical Engineerin

Potentials of torrefied pine sawdust as a renewable source of fuel for pyro-gasification : Nigerian and South African perspective

Abstract: The impacts of fossil energy on the climate and environment emphasize the need for alternative energy resources. The use of waste wood is one such method to potentially reduce fossil-based energy dependence. However, raw biomass fuel properties are generally poor and unpredictable, thus requiring pretreatment to maximize their energy potentials for an efficient conversion to syngas via pyrogasification. Two species of pine sawdust (PSD) wastes generated in abundance from large-scale timber industries in Nigeria and South Africa were investigated for improvements in their fuel properties after torrefaction. Samples were torrefied under optimum conditions of 300 °C and 45 min. Different analytical procedures show that the higher heating value (HHV), enhancement factor, energy density, and solid yield of the Nigerian PSD exceeded those of their South African counterpart by 2.38, 5.37, 3.49, and 11.15%, respectively. The HHV of the torrefied fuels increased by 57.29 and 37.9% for the Nigerian and South African PSDs, respectively, when compared to the raw fuels. Also investigated were improvements in their H/C and O/C ratios and thermal degradation at varied heating rates

Dataset on the assessment of the environmental, economic and energy parameters of 5 MW CHP co-gasification plant using South African coal, biomass and waste-tyre

The data provided in this article supplements the data information provided in “Techno-economic analysis of electricity and heat production by co-gasification of coal, biomass and waste tyre in South Africa” [1]. The generation of the data considered co-generation of a coal sample (Matla coal) with pine sawdust, sugarcane bagasse, corn cob, and waste tyre at a blend ratio of 1:1, 3:2, and 4:1. The cost evaluation of the use of the feedstocks was considered with feedstock costing (WFC) and without feedstock costing (WOFC). Profitability assessment tools for the case study included NPV, IRR and PBP. The data as contained in this article could be useful for a quick decision making on a similar project by the government and stakeholders in the sector. Keywords: Co-gasification, Biomass waste, Coal, Electricity and heat production, Techno-economic, South Afric

Thermogravimetric properties and degradation kinetics of biomass during its thermochemical conversion process

Please read abstract in the article.The Research and Innovation Support and Advancement in collaboration with the National Research Foundation, South Africa (DST-NRF).http://www.elsevier.com/locate/matpr2024-08-17hj2023Chemical Engineerin