Co-gasification of waste biomass-low grade coal mix using downdraft gasifier coupled with dual-fuel engine system: Multi-objective optimization with hybrid approach using RSM and Grey Wolf Optimizer

Abstract

The looming global crisis over increasing greenhouse gases and rapid depletion of fossil fuels are the motivation factors for researchers to search for alternative fuels. There is a need for more sustainable and less polluting fuels for internal combustion engines. Biomass offers significant potential as a feed material for gasification to produce gaseous fuel. It is carbon neutral, versatile, and abundant on earth. The present study thus explores a mix of different feedstocks, such as mahua wood and low-grade coal for downdraft gasifiers. The resultant producer gas (PG), after cooling-cleaning will be used as the gaseous fuel to run the diesel engine in dual-fuel mode, while a tiny quantity of linseed biodiesel-diesel blends as B20 (20 % biodiesel + 80 % diesel) will be supplied as injected pilot fuel. The data from experimental work at different engine operation settings was employed to develop a prediction-optimization model using a twin approach of RSM and Grey wolf optimization (GWO). The three control factors for the engine were compression ratio (CR) 17 – 17.5 – 18, equivalence ratio 0.12–0.41, and engine loads in the range of 10–100 % were used to collect data on response variables i.e., brake-thermal efficiency (BTE) and emission data (CO2, NOx, UHC, and CO). A comparative approach of RSM and GWO was utilized for the multi-objective optimization revealing the best results were attained at 17.65 CR, 0.4 ER, 82.55 % engine load in the case of GWO.