Potential of Manihot Esculenta (Cassava) Peels for Electricity and Heat Co-Generation in Nigeria

Nigeria is the largest producer of cassava in the world and the peel accounts for between 5 -15% of the tuber. Cassava peel  is often left unattended in the country, making it a source of methane gas which is one of the culprits of global warming.  Agricultural residues are good sources of renewable energy. This study investigated the potential of electricity and heat  generation from cassava peels. The dried peel was ground and used for proximate analysis according to ASTM D 5142-04  procedure, from where moisture, ash, Volatile Matter (VM) and the Fixed Carbon (FC) contents were determined. The  Higher Heating Value (HHV) of cassava was calculated using the FC. Performance of four plants tagged A, B, C and D  were simulated using thermodynamics equations. Plant A was simulated as a boiler-steam turbine combination, Plant B,  gasifier-boiler steam turbine, Plant C, gasifier-gas turbine and Plant D, gasifier-internal combustion engine combination.  Parameters investigated were power output, heat output, annual electrical energy generation per peel mass. Results gave  the moisture, ash, VM and FC contents as 6.53, 3.78, 89.57 and 6.65 % respectively while the HHV was determined to be  15.422 MJ/kg. Estimated power output was 2.51 x 105, 1.78 x 105, 1.39 x 106 and 1.26b x 106 kW for Plants A, B, C and  D respectively. In a like manner, the heat output is1.02 x 107, 7.24 x 106, 8.84 x 106 and 1.06 x 107 MJ/h. Annual electrical  energy output was determined to be 9.03 x 108, 6.42 x 108, 5.00 x 109 and 4.52 x 109 kWh and the electrical energy gener ation per cassava peel consumption was 0.202, 0.144, 1.121 and 1.009 kWh/kg for Plants A, B, C and D respectively. Cas sava peel possesses good potential for heat and electrical energy co-generation in Nigeria.