The potential use of hydrothermally treated municipal solid wastes as an alternative fuel for power generation in Zimbabwe = The potential use of hydrothermally treated municipal solid wastes as an alternative fuel for power generation in Zimbabwe

다국어 초록 (Multilingual Abstract)

The quality of Municipal Solid Waste (MSW) management remains at a very low level in Zimbabwe. The challenges posed by inadequate and inappropriate tools for waste disposal are evident as Zimbabwe’s history is clouded by a string of fairly recent cholera and typhoid outbreaks. The urban areas are teeming with illegally dumped litter as cash-strapped local authorities are unable to collect the waste. An alternative strategy to prevent the problems associated with poor MSW disposal practices is needed. Waste management based on social, economic, and environmental conditions is necessary for the environment-friendly development of Zimbabwe. Electric power supply is also an important issue from the viewpoints of the economic growth and environmental protection. In Zimbabwe, where shortages in domestic coal production adversely affect electricity supply, a waste-to-energy technology can be a promising solution for waste related problems.
The hydrothermal conversion of municipal solid wastes into green products has received much attention in recent years. The partial substitution of coal by hydrothermally treated MSW has been tested extensively and the optimum blend levels are well known. However, limited studies have looked at the application of this technology for power generation in developing countries at a national level. In Zimbabwe, where MSW collection and disposal is less developed, the feasibility of hydrothermal technology largely depends on the quantities and quality of waste that can be converted amongst other factors be they social or economic. The aim of this study is therefore to determine the potential maximum amount of collectable MSW that can be converted for co-burning with coal if the technology is implemented.
A desk research approach was used to quantify and characterize Zimbabwe’s MSW. The qualitative analysis and quantification of the coal-alternative fuel produced by hydrothermal conversion of Zimbabwe MSW was predicted using a model. The model was developed using extensive experimental data in published works covering hydrothermal conversion, Zimbabwe MSW characteristics, typical heating values, ultimate and proximate analysis of MSW components. Coal consumption at Zimbabwe’s coal-fired power stations was estimated based on reported plant capacities and Zimbabwe coal chemistry. Results from the model were compared with other investigations to establish confidence in the approach.
The preliminary findings indicate that the quantities of MSW and theoretical yield of coal-alternate fuel justify the possibility of utilizing hydrothermal technology. When all of the coal-alternate fuel produced from MSW is utilized in coal-fired power plants with dependable operation capacity, 14.8% of the coal will be substituted, which is less than maximum acceptable substitution ratio (20%). However, further investigations such as cost analysis, or social feasibility analysis still need to be conducted to provide a conclusive answer to the question on the applicability of this technology in Zimbabwe.