ACS Omega. 2023 Aug 10;8(33):30598-30611. doi: 10.1021/acsomega.3c04209. eCollection 2023 Aug 22.
A new sustainable solid carbon catalyst has been developed for biodiesel synthesis using pyrolytic coconut shell ash (CSA). The CSA support was loaded with various amounts of potassium carbonate (K2CO3), and response surface methodology with a central composite design was used to optimize the transesterification process. The best-performing catalyst was the 30 wt % K2CO3/CSA catalyst. The optimal conditions included a catalyst loading of 3.27 wt %, methanol:oil molar ratio of 9.98:1, reaction time of 74 min, and temperature of 65 °C, resulting in an obtained biodiesel yield of 97.14%. This catalyst was reusable for up to four cycles, but a reduction in the biodiesel yield was observed due to potassium ion leaching during the recovery process. A techno-economic analysis to assess the financial viability of the project revealed a net present value of 5.16 million USD for a project lifetime of 20 years, a payback period time of 2.49 years, and an internal rate of return of 44.2%. An environmental assessment to evaluate the impact of global warming potential from the production of biodiesel revealed a lower level of carbon dioxide emission (1401.86 ton/y) than in the conventional process (1784.6 ton/y).