• Energy Research
• 2021-2025close

Utilization of mesoporous materials to enhance structure–performance relationship of Fischer–Tropsch catalysts.

The effectiveness of the adsorption process is determined by the type of adsorbent used, but some adsorbents require a significant amount of processing to achieve the desired quality, and this has become a drawback economically and environmentally. This study focused on mitigating the issue of waste management and land pollution by using amarula waste biomass, which is a low-cost adsorbent that is obtained from the industrial waste by-product. The amarula shell (AmSh) waste was found to have a higher adsorption efficiency of 30 ± 3% compared to the amarula seed (AmSe) waste and the amarula fruit (AmWa) waste, which had 19 ± 5% and 9.5 ± 0.7% efficiency, respectively. It was found that the amarula waste biomass performed better at lower adsorption temperatures. The adsorption capacity was found to decrease with an increase in the quantity of the biomass. Kinetic models were applied to the experimental data. Thermodynamic parameters were also studied to determine the spontaneity of the adsorption process. The characteristics of both the fresh and used amarula waste biomass was analyzed by using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy with Energy Dispersive Spectroscopy (FESEM-EDS), Brunauer-Emmett-Teller (BET) and Thermogravimetric Analysis (TGA). It was then concluded that cellulose and hemicellulose structures in amarula waste biomass played a major role in reducing the content of dibenzothiophene in model diesel fuel.

Several anthropogenic activities reduce the supply of freshwater to living organisms in all ecological systems, particularly the human population. Organic matter in derived wastewater can be converted into potential energy, such as biogas (methane), through microbial transformation during anaerobic digestion (AD). To address the current lack of data and values for wastewater generation in Sub-Saharan Africa, this review analyzes and estimates (at 50% and 90% conversion rates) the potential amount of wastewater-related sludge that can be generated from domestic freshwater withdrawals using the most recent update in 2017 from the World Bank repository and database on freshwater status in Sub-Saharan Africa. The Democratic Republic of the Congo (DRC) could potentially produce the highest estimate of biogas in Sub-Saharan Africa from domestic wastewater sludge of approximately 90 billion m3, which could be converted to 178 million MWh of electricity annually, based on this extrapolation at 50% conversion rates. Using same conversion rates estimates, at least nine other countries, including Guinea, Liberia, Nigeria, Sierra Leone, Angola, Cameroon, Central African Republic, Gabon, and Congo Republic, could potentially produce biogas in the range of 1-20 billion m3. These estimates show how much energy could be extracted from wastewater treatment plants in Sub-Saharan Africa. AD process to produce biogas and energy harvesting are essential supplementary operations for Sub-Saharan African wastewater treatment plants. This approach could potentially solve the problem of data scarcity because these values for Freshwater withdrawals are readily available in the database could be used for estimation and projections towards infrastructure development and energy production planning. The review also highlights the possibilities for energy generation from wastewater treatment facilities towards wastewater management, clean energy, water, and sanitation sustainability, demonstrating the interconnections and actualization of the various related UN Sustainable Development Goals.

Abstract Energy in the form of plasma was used to thermally decompose wood in the presence of O2. Heat required to sustain the gasification reactions was provided indirectly by: (i) the electricity fed to the nitrogen N2 plasma torch; (ii) the chemical potential of the oxygen fed to the reactor. Two sets of experiments were carried out at 700 °C and 900 °C in a plasma reactor to investigate syngas composition variation. The results show that increasing the O2 flow rate reduced the lost work potential caused by the plasma electrical energy being degraded to heat, but increased the lost work during the reaction, as well as across the process, thus increasing the irreversibility of the overall process. Furthermore, a plasma torch that requires cooling is not the best way to add high temperature heat in form of electricity to the gasifier, as this results in enormous heat and work loss.

Abstract This paper proposes that the approach of social acceptance of renewable energy technology needs to include the concept of naturalness to understand the social rejection of biogas technology. Because naturalness concerns are not only strongly associated with the physical emotions of disgust and fear but also with disgust as a moral emotion, which is experienced as an indignity to the community, they have the potential to prevent energy projects from succeeding. Results from a survey and a case study conducted in South Africa demonstrate that relative to other renewable energy technologies, biogas technology elicited stronger naturalness concerns and the emotions of disgust and fear (Study 1: N = 452) and that indignity experiences of community members of an informal settlement were sufficient to reject a small scale biogas technology project (Study 2: N = 155). The implications of our findings are discussed and solutions are provided to address the naturalness concerns about biogas technology.

Immobilized cobalt nanoparticles on SiO2 reduced via hydrogenation–carburization–hydrogenation (HCH) afforded a 40% higher CO conversion compared to the standard H2treatment. The HCH treatment increased the catalyst reducibility and the dispersion of Co-hcp, with a high intrinsic activity for Fischer–Tropsch synthesis (FTS), via the Co2C intermediate. It is postulated that the Co2C was responsible for the high CH4 and olefin selectivity observed over the HCH treated sample, which resulted in a detrimental effect on the selectivity of liquid fuels. Nonetheless, this is a groundbreaking contribution to future FTS catalyst design and for synthetic fuel production.