Energy Characteristics of Prosopis juliflora with Binary Combination of Maize Cobs and Bagasse Agricultural Waste on Briquette Production

Abstract

The demand for energy in Kenya continues to grow despite efforts to increase the country's installed power capacity. There is need to explore clean and sustainable energy sources to meet increasing energy demand. Briquette production is an affordable and environmentally friendly source of energy that uses various feedstocks such as woody biomass, crop residues, municipal, and industrial wastes. The study aimed to investigate the use of Prosopis juliflora as a feedstock for briquette production and evaluate the influence of a binary combination of maize cobs and bagasse on the characteristics of the briquettes; this was done by establishing proximate and ultimate energy parameters. Binary combination ratios were done at 25% and 50% of the total sample weights. Proximate analysis results showed that using Prosopis juliflora in its pure form for briquette production achieved moisture content of 5.59±0.09%; volatile matter of 77.49±1.98%; ash content of 3.12±0.16%; fixed carbon of 19.39±1.82% and calorific value of 18.99±0.21 MJ/kg. Ultimate elemental composition was 46.26±0.70% carbon, 5.75±0.14% hydrogen, 0.27±0.03% nitrogen and 0.44±0.05% Sulphur; which were all within desirable range for briquette production. Experimental analysis showed that the binary combinations of maize cobs and bagasse increased the calorific value of Prosopis juliflora briquettes with 50% Prosopis juliflora and 50% Maize cobs fuel combination being the optimal fuel choice for briquette production since it had high calorific value of 19.73±0.05 MJ/kg compared to the other binary combination briquettes. The study's findings revealed a positive Net Present Value of Kshs. 7,863,216 and a higher Internal Rate of Return of 55% compared to a nominal discount rate of 13%; a discounted payback period of 2.07 years and a profitability index of 1.57 indicating that both the technology and biomass material of Proposopis juliflora and maize cobs are economically viable for use in producing cheaper and quality briquettes.