Feasibility study of coconut shell biochar production using community-scale biochar kiln

The enormous coconut shell waste from local farmers and manufacturers has caused negative environmental and economic impacts in Thailand. A low-cost, small-scale pyrolysis kiln comprised of a cylindrical tank, gas circulating pipes, a kiln stand, and a manual drum lever was constructed and used to produce biochar from coconut shells in this study. The air intake and holding times for the biochar production process were varied. The biochar yield was 30.67% to 36.22%, or 4.6 kg to 5.4 kg per day per unit. The biochar porosity and fixed carbon content increased as the air intake and holding times were increased. The BET surface areas were 7.54 m²∙g-1 to 63.17 m²∙g-1. The pH values of biochar were alkaline, in the range of 7.34 to 10.24. Therefore, biochar can be used as a soil amendment material. The Net Present Value (NPV), the Internal Rate of Return (IRR), and the payback period are 52,757 THB (1,459.79 USD), 18.71%, 4 years, 10 months, and 27 days, respectively. According to economic analysis, investing in coconut shell biochar production under optimal conditions using the developed kiln is acceptable and can be viewed as a potential approach to providing additional economic benefits for coconut-based enterprises and the Thai community.