Assessment of the Potential Utilization of Sugarcane Derived Press Mud for Electricity Generation in South Nyanza Sugar Zones, Kenya

Abstract

Sugarcane derived press mud (SDPM) is among the 3 major by-products found in the process of raw sugar production; these are Bagasse, Press Mud and Molasses. A precipitate, which is called press mud weighs about 4-5% of the cane weight. The aim of this study was to assess the potential for utilization of sugarcane derived press mud as a renewable energy resource for biogas production and generation of electricity. Sugar derived press mud samples were collected from South Nyanza Sugar zones (SONY, Sukari industries and Transmara Sugar Companies). Chemical treatment and characterization analysis of its parameters were carried out at Kenya Sugar Research Foundation laboratories in Kisumu City. Production of biogas and biogas composition analysis was carried at JKUAT. Samples taken to JKUAT were blended with cow dung at a ratio of 3:1 as inoculum. The gas compositions, upgrading and gas yields were studied. The result of the compositional analysis of the sugarcane press mud from the three sugar factories had variations of (p≤0.05) in all parameters analysed. Average values were: Moisture content 63.1 ±1.0%, ash content 16.1 ±1.0%, C/N ratio 19.6 ±1.0% and pH 7.3-7.6. Biogas was found to contain 40% - 52% methane (CH4), 30% - 32% carbon dioxide (CO2), 13% - 15% nitrogen (N2) and 1%-2% hydrogen sulphide (H2S).The raw biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content up to 70% - 71% this was good concentration compared to the upgraded biogas from water hyacinth of 70%-76%. From theoretical calculations using Buswell equation, it was found that for every 1kg of mixed SDPM and cow Dung (inoculant) we can generate 72.0 kWh. When a small generator was used to produce electric power with the clean biogas 1M3 produced 3.54kWh. And when the annual potential of SDPM biogas converted to electric power it was found that it could produce 453.5MWh per annum. The study concludes that sugarcane press mud is a potential feedstock for biogas production. For 1kg of SDPM produced 2.341/kg and the annual potential of SDPM biogas converted to electric power was approximated at 453.5MWh per annum