Syngas optimization and tar reduction via multistage catalytic gasification: Effects of catalyst pore, catalyzer stage, and temperature profile

• Published in: South African journal of chemical engineering 2024-04, Vol.48, p.246-253
• Main Authors: Wiyono, Apri, Aziz, Muhammad, Sholehudin, Agus, Sukrawan, Yusep, Purnawan, Anggrainy, Rani, Kadja, G.T.M, Pambudi, Nugroho Agung
• Format: Article
• Language: English
• Subjects: Catalyst pore; Catalyzer; Energy; Multistage catalytic gasification; Zeolite
• ISSN: 1026-9185
• DOI: 10.1016/j.sajce.2024.02.004

•Biomass is known to be potential source of carbon energy which can be used by various thermochemical methods such as pyrolysis and gasification.•The multistage catalytic gasification (MCG) of coconut shells was examined by using thermal and catalytic cracking processes (two-step gasification).•The addition of multiple stages in catalytic cracking process showed stable breakdown of hydrocarbon chains while exposing the pyrolysis products to lighter compounds.•Several parameters that affected the syngas production were the material of the catalyst, its surface area and its pore structure. Biomass stands out as a promising availability source of sustainable carbon energy due to its low pollution profile and versatile applications. This study investigates the multistage catalytic gasification (MCG) of coconut shells, employing thermal and catalytic cracking processes in a two-step gasification approach. Local source catalysts, including dolomite, kaolin, and zeolite, were utilized as eco-friendly additives at temperatures ranging from 200 to 300 °C. Zeolite emerged as the most effective catalyst, producing the highest energy content at 6.21 MJ/kg. Conversely, kaolin resulted in higher CO2 emissions. A blend of zeolite and kaolin achieved the highest energy content at 5.43 MJ/kg. However, the combined use of catalysts showed negligible improvements compared to individual catalysts. The study demonstrates that multistage catalytic gasification enhances syngas production and reduces tar content during the gasification of coconut shells. Optimal pyrolysis temperatures were identified within the 500–600 °C range. In conclusion, the introduction of multiple stages in the catalytic cracking process ensures a stable breakdown of hydrocarbon chains, promoting the exposure of gasification products to lighter compounds. Multistage catalytic gasification enhances oxygen supply for oxidation, thereby improving syngas production while mitigating tar and ash content.