https://ir.cut.ac.zw:8080/xmlui/handle/123456789/3 Fri, 05 Jun 2026 23:17:56 GMT 2026-06-05T23:17:56Z https://ir.cut.ac.zw:8080/xmlui/handle/123456789/275 Pyrolysis characteristics and kinetics of acid tar waste from crude benzol refining: A thermogravimetry–mass spectrometry analysis Chihobo, Chido H; Chowdhury, Arindrajit; Kuipa, Pardon K; Simbi, David J Pyrolysis is an attractive thermochemical conversion technology that may be utilised as a safe disposal option for acid tar waste. The kinetics of acid tar pyrolysis were investigated using thermogravimetry coupled with mass spectrometry under a nitrogen atmosphere at different heating rates of 10, 15 and 20Kmin-1. The thermogravimetric analysis shows three major reaction peaks centred around 178°C, 258°C, and 336°C corresponding to the successive degradation of water soluble lower molecular mass sulphonic acids, sulphonated high molecular mass hydrocarbons, and high molecular mass hydrocarbons. The kinetic parameters were evaluated using the iso-conversional Kissinger–Akahira–Sunose method. A variation in the activation energy with conversion revealed that the pyrolysis of the acid tar waste progresses through complex multi-step kinetics. Mass spectrometry results revealed a predominance of gases such as hydrogen, methane and carbon monoxide, implying that the pyrolysis of acid tar waste is potentially an energy source. Thus the pyrolysis of acid tar waste may present a viable option for its environmental treatment. There are however, some limitations imposed by the co-evolution of corrosive gaseous components for which appropriate considerations must be provided in both pyrolysis reactor design and selection of construction materials Fri, 01 Jan 2016 00:00:00 GMT https://ir.cut.ac.zw:8080/xmlui/handle/123456789/275 2016-01-01T00:00:00Z https://ir.cut.ac.zw:8080/xmlui/handle/123456789/274 Determination of Cocombustion Kinetic Parameters for Bituminous Coal and Pinus Sawdust Blends Marangwanda, Garikai T.; Madyira, Daniel M.; Chihobo, Chido H. Cocombustion of bituminous coal (HC) and Pinus sawdust (PS) was investigated in this paper with the aim of determining the kinetic parameters relevant to cocombustion reactions of their fuel blends. PS was used because it is a waste biomass product capable of generating energy. Motivated by the need to partly substitute HC used in existing boilers with PS, the optimum kinetic parameters at different blending ratios were thus investigated with the ultimate goal of diversifying the energy portfolio for these boilers. Blended samples were prepared with a PS substitution by mass ranging from 0 to 30%, thus producing five samples, namely:100HC, 90HC10PS, 80HC20PS, 70HC30PS, and 100PS. A simultaneous thermogravimetric analyzer was used to investigate the degradation of the fuel samples under a synthetic air atmosphere using 5, 12.5, and 20 °C/min heating rates. The kinetic parameters were evaluated using the distributed activation energy model (DAEM) due to its ability to evaluate complex parallel chemical mechanisms. The influential homogenous volatile combustion and heterogenous combustion stages produced an increasing trend for activation energy (Ea) with increased PS (100HC to 70HC30PS) from an average of 61.80–104.34 kJ/mol while the pre-exponential factor increased from 1.31 × 105 to 6.52 × 108. Generally, blending of HC with PS did not produce a linear variation of the kinetic parameters; thus, by using various plots, an optimum blending ratio of 80HC20PS was deduced. Sat, 01 Jan 2022 00:00:00 GMT https://ir.cut.ac.zw:8080/xmlui/handle/123456789/274 2022-01-01T00:00:00Z https://ir.cut.ac.zw:8080/xmlui/handle/123456789/273 A systematic review of the techno-economic assessment and biomass supply chain uncertainties of biofuels production from fast pyrolysis of lignocellulosic biomass Makepa, Denzel C.; Chihobo, Chido H.; Ruziwa, Walter R.; Musademba, Downmore Biomass plays an essential role in enhancing global energy security and decreasing carbon emissions as a promising renewable energy option. Comprehensive techno-economic assessments have been carried out to spark industry stakeholders' interest and increase their investment in biomass-based enterprises. To provide a more accurate and reliable feasibility estimate, the evaluation must also take into account a variety of uncertainties in the biomass conversion industry. This review aims to present an overview of the various types of methodologies or techniques used in the techno-economic assessment of the viability of biomass conversion processes, and highlight the uncertainties that need to be taken into account in the evaluation model. A systematic literature review is used where four electronic databases viz., Scopus, Web of Science, Dimensions, and PubMed were used to identify the most recent original research articles in peer-reviewed journals. A total of 346 studies, covering the period 2012–2022 were screened for relevance to the study. Seventy-eight records (n=78) which include only original research articles met the inclusion criteria. The review identified several financial factors and uncertainties that affect the economic performance of fast pyrolysis systems. Furthermore, upgrading the bio-oil to transportation fuels and value-added biochemicals can significantly improve the economic performance of fast pyrolysis plants as opposed to selling raw bio-oil. Sun, 15 Jan 2023 00:00:00 GMT https://ir.cut.ac.zw:8080/xmlui/handle/123456789/273 2023-01-15T00:00:00Z https://ir.cut.ac.zw:8080/xmlui/handle/123456789/272 The adoption of energy efficiency and a policy framework for Zimbabwe Dzobo, Oliver; Tazvinga, Henerica; Chihobo, Chido Hermes; Chikuni, Edward Recent policy discussions on energy use in Zimbabwe sparked interest in the economic case for energy efficiency, suggesting the need to investigate the relevant costs and benefits. This paper investigated the potential of energy efficiency in manufacturing industries in Zimbabwe. Data col lection was done using questionnaires, walk-through audits and semi-structured interviews. The data set was then analysed using regression analysis. The results show that there would be signifi cant potential energy saving in Zimbabwe through adopting various energy efficiency programmes. The main energy efficiency barriers identified were: poorly structured electricity tariffs; risk of pro duction disruption; resistance of operational staff to a changed working style; lack of coordination between company divisions; lack of information on energy efficiency programmes; and lack of sup port from senior management on issues that relate to energy efficiency. A straightforward energy efficiency policy framework is proposed, and three main players identified, namely government, energy regulator, and research institutions. Sat, 01 Aug 2020 00:00:00 GMT https://ir.cut.ac.zw:8080/xmlui/handle/123456789/272 2020-08-01T00:00:00Z