Dual response surface methodology-based optimization of biomass blend and densification process for sugarcane bagasse, sawdust and areca leaf plate residues briquettes with improved thermochemical and mechanical properties

Abstract

Most of the biomass residues from agricultural lands in India are either burned in the atmosphere or take a long time to decompose in the soil. The present work focuses on collecting high-calorific agricultural residues such as sugarcane bagasse (SB), sawdust (SD), and areca leaf plate residues to develop an optimal briquette based on their calorific value (CV). A total of 20 binderless biomass briquette samples were produced using SB, SD and areca leaf plate residues based on a face-centered central composite design. Analysis of variance and response surface methodology (RSM) were used to evaluate the influence of biomass blend and determine the optimum composition. The optimal CV of 18.075 (MJ kg−1) and ash content of 1.831%, with input factors of SB (45 g), SD (12.5 g), and areca leaf plate residues (2.5 g), were obtained from the regression model. A hydraulically operated pressing mechanism, including a controller, is designed to produce different combinations of briquettes from agro-industrial residues. The mechanical characteristics of more than 30 combinations of briquettes were analyzed and the best combinations were selected based on densification factors. RSM was used to determine the significance of compression pressure and retention time (RT) on the compressive strength, shatter index, and density. The optimal densification variables achieved were 150 bar and 25 min for compression pressure and RT, respectively. In this study, the optimization was limited to the three biomass feedstocks, and the obtained CV was not controlled by automation. In future, the findings furnish a basis for the development of automated and IoT-based biomass briquetting systems for making biofuels with consistent CV. Overall, densified biomass briquetting is an alternative energy source to fossil fuels in industrial applications and also reduces pollution.