Combustion Characteristics and Emission of Briquette Fuel from Biomass Mixed with Glycerin

ABSTRACT

This research investigates combustion characteristics and emissions of fuel briquettes made of biomass (rice husk and rice husk char) mixed with molasses and glycerin. An experiment was designed to find the best fraction of glycerin in fuel briquettes. The mixing ratios of biomass to molasses to glycerin tested are 90:10:0, 85:10:5, 80:10:10, 75:10:15, 70:10:20, and 65:10:25 by mass. Briquettes were combusted in an insulated burner in two conditions where air to fuel ratios of 16 and 24 times the stoichiometric optimal A/F_ratio were used at the initial stage of combustion. During the experiment, monitored parameters were time/temperature profile, combustion rate, and emissions of gases, such as CO, CO₂, NO_x, and Acrolein. Combustion characteristics show that glycerin raises the combustion temperature and combustion rate by 22% and 33.7%, respectively. The exhaust gas emission test reveals that CO₂ emissions are 11–15%, while the amounts of CO, NO_x, and Acrolein gas are 465–1128, 37–154, and 0.1–35.3 ppm, respectively. In conclusion, the most suitable glycerin ratio in briquettes was found in the 80:10:10 mixture because it gives combustion characteristics and emissions within the health standard.

KEYWORDS:

• Acrolein gas
• Biomass briquette
• Briquette combustion
• Emission
• Glycerin

Additional information

Funding

This research project was financially supported by the Higher Education Research Promotion and National Research University Project of Thailand, Office of the Higher Education Commission, through the Biofuel Cluster of Khon Kaen University. The authors gratefully thank the Center for Alternative Energy Research and Development, Khon Kaen University, Thailand.