| Abstrakt: |
Energy for household use is expensive and is thus less available to communities, especially in developing countries. In Kenyan rural households, the primary source of domestic cooking fuel is either locally available firewood, charcoal produced through gradual pyrolysis of these firewood, or biomass briquettes. Nonetheless, there have been minimal investigations that characterize and compare typical firewood species and the associated charcoal fuels in terms of moisture content, calorific values, and their relationships. Consequently, this study sought to ascertain the moisture content, ultimate analysis, and calorific values of Grevillea robusta, Arundinaria alpina, Eucalyptus globulus, Azadirachta indica, Gliricidia sepium, Adansonia digitata L., Cyprus,and Acacia auriculiformiswood fuels, and the corresponding charcoal and briquettes in Bomet, Narok, Taita Taveta, and Mombasa Counties. The bomb calorimeter method was used to determine the calorific values while the elemental analyzer was used to determine carbon, nitrogen, sulfur, and oxygen levels in the fuel. Moisture content of the wood fuels ranged from 2.36 ± 0.01% to 4.93 ± 0.02%, briquettes from 2.57 ± 0.02–3.22 ± 0.07%, and charcoal, from 2.02 ± 0.01–2.73 ± 0.05%. Briquette samples had the highest carbon composition of 74.69% and 75.77%, followed by charcoal and firewood, respectively. It was found that firewood fuels had a higher oxygen content (39.47–49.96%) than the other fuels (21.71–36.54%). In elemental analysis, the majority of the samples had sulfur and nitrogen content of less than 1% while the hydrogen content ranged from 1.26% to 6.04%. The calorific values of the solid fuels ranged between 13.13 ± 0.11 MJ/kg and 32.71 ± 0.19 MJ/kg. The findings suggest a relationship between moisture content and calorific values since low moisture content fuels had high calorific values which could be attributed to the increased value of the carbon-to-oxygen (C/O) proportion (ranging from 0.94 to 3.36). Based on the calorific value analysis, the order of fuel strength was found to be; charcoal > firewood > briquettes. As a result, the study's findings demonstrate that the proximate, ultimate, and calorific values analyses of solid fuel play a vital role in determining the best fuel with higher energy values in accordance with the International Energy Agency's (IEA) requirements. |
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