Investigation of Agricultural Residues Gasification for Electricity Production in Sudan as an Example for Biomass Energy Utlization under Arid Climate Conditions in Developing Countries
This study examines the possibility of electricity production through gasification of agricultural residues in Sudan. The study begins in Chapter 1, by providing general contextual analysis of the energy situation (production and consumption patterns) in Sudan with specific focus on electricity. It proceeded to study the potential of Petroleum, Biomass and other renewable sources for electricity production. Dramatic increase in electricity production was found to be essential especially through decentralised power plants as the current electricity production services cover ~ 13 % of the population of Sudan. Biomass potential in Sudan justifies the use of agricultural residues as energy source; its potential was estimated by ~ 350000 TJ/a. Further, the urban centres of arid regions in western Sudan were identified as the target group for this study. In chapter 2, specific investigations for selected study area through field work using statistical tools such as questionnaires, interviews and field observation show that income is highly correlated to electricity consumption. The flat rate system did not result in higher consumption thus the assumption that this consumption will not drastically change in the next 10 years could be accepted. As orientation value for BGPP, 8000 tons of GN.S are available annually, the average electricity consumption is ~ 4 kWh/day/family while acceptable price could be 40 SDD/kWh (0.15 €). In chapter 3, literature review was carried to spot out the comparative merits of the gasification technology and the most optimum gasifying and electricity production system. As a result downdraft gasifier and ICE were suggested as suitable systems. In chapter 4, fuel properties and fuel properties of agricultural residues were studied, different samples were tested and the results were presented. The main conclusions derived were: fuel properties of agricultural residues are modifiable properties, so utlization planning is possible as for any other energy resource. In Sudan, Baggase, Groundnuts shells and Roselle stalks could be considered as possible fuels. The experimental work done in chapter 5 showed that GN.S could be gasified in down draft gasifiers, which are less costly and simpler to operate than circulating systems. Acceptable values of gas thermal properties (c.v.~ 4 MJ/Nm3, 30 % of burnable gases) at fairly continuing processes were obtained. In chapter 6, a concept for biomass power plant was drafted, the main components are: downdraft, air based gasifier connected to ICE, multi-stage gas cleaning system (cyclones, washer and filters) mechanical ash removal and semi closed water cycle. Main operation measures are: electricity is the sole product; working time is 150 day/year between mid Novembermid Mars. Environmental hazards of waste management e.g. flue gas emission and waste water management are the limiting factors. In the last part of chapter 6 an economic analysis was carried out. At a value of 3000 €/kW for the initial system and fuel price of 100000 €/year for ~6 GWh then a price of 0.23 €/kWh and a return period of 24 years could be obtained. The study concludes in chapter 7 that biomass gasification under the local conditions has its comparative merits however a high institutional support is needed at the beginning.
Gasification, Biomass-Utlization ,Renewable energy, energy planning in developing countries, Biomasse-Nutzung, Vergasung, regenerative Energie, Energieplanung in Entwicklungsländern
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