Cleaner Engineering and Technology (Dec 2020)
Off-grid electricity generation in Nigeria based on rice husk gasification technology
Abstract
Nigeria is purely an agrarian nation and the people depend on agriculture for survival. One of the missing links to wealth creation in Nigeria is lack of economic exploitation of abundant agricultural wastes. Instead of wealth creation, rice husk has become a serious threat to the environment. The unutilized rice husks in rice mills in Nigeria generate millions of tons of C02 when burnt. This increases environmental degradation and deaths associated with respiratory diseases. The sustainable use of this rice husk for bioenergy applications such as electricity generation at low cost, to mitigate greenhouse gas emissions is imperative. In this paper, an off-grid gasification power supply option for Adani, in Uzo-Uwani Local Government Area of Enugu state, of eastern Nigeria is presented. A detailed load assessment and availability of rice husk for power generation in the study area was conducted. This information was used to design the gasification system. The gasification system was designed based on the mass flow rate of producer gas required to power the gas engine at full load. The gasifier was designed downdraft with air and steam as the oxidizing agent, in order to maintain uniform temperature in the oxidation and reduction zones. Furthermore, techno-economic analysis approach was used to determine the economic viability of the designed power system considered in this study. The estimated total load demand of the study area is 850.054kW. The estimated total daily, monthly and yearly energy demands of the study area are: 8,991 kWh, 269,736.42 kWh and 3,236,837.04 kWh. The annual availability of rice husk in the study area is 3,636t/y and it has potential of 1.52MW power generation with daily, monthly and yearly energy generation of: 36.48 MWh, 1,094.4 MWh and 13,132.8 MWh. This potential of electricity generation has power station capacity of 1.9 MVA, which is approximately equal to 2 MVA. The Levelized Cost of Electricity of the designed power system is 3.6 Naira/kWh, which is cheaper than 30.93 Naira/kWh tariff bill by Enugu Electricity Distribution Company to its R2S customers. Based on the proposed rice husk gasification system, a community could generate power to meet their electricity demand in most economical way, thereby reducing emission, waste and saving cost translating to sustainable development.
