Design and Development of Energy Recovery System for Continuous Biochar Production System

Abstract

The experimental study was carried out on designing of energy recovery system consisting of cooling chamber and syngas burner for continuous biochar production system (Pratap Kiln). Biochar production system is used for pyrolysis of agro residues such as Groundnut Shell (GS), Chickpea Straw (CS) and Wheat Straw (WS). Cooling chamber was design to recover the bio-oil from the condensable gases produced during the pyrolysis of the selected feedstock whereas premixed syngas burner was used to combust the remaining non condensable gaseous fraction of syngas. The pyrolysis system work at temperature 450°C and residence time of 4 min. The yield of biochar and biooil, and physiochemical properties were determined. The syngas was analysed for its composition and heating value. newlineThe result shows that, the maximum biochar yield was found in CS at 35% followed by WS and GS, i.e. 33% and 29%, respectively which is depends on the rate of devolatilization and type of feedstock. The bio-oil recovery in GS, CS and WS was 31%, 26% and 30% respectively, whereas the syngas production was 40%, 39% and 37% respectively. The viscosity of the bio-oil was found maximum in GS followed by the CS and WS i.e. 32.3, 30.1 and 29.9 respectively. The density of the bio-oil was found maximum in GS followed by CS and WS i.e. 1.04, 1.02 and 1.01. The bio-oil recovered was mostly acidic in nature as the pH was below 4 in all cases. The biochar produced from GS, CS and WS have heating value of 23.79, 20.91 and 22.88 MJ/kg. The bio-oil produced from GS, CS, WS have heating value of 20.63, 20.41 and 21.76 MJ/kg. The syngas produced from GS, CS, WS have heating value of 4.91, 5.49 and 5.02 MJ/m3. The effectiveness of the cooling system was found 43.15%. The capital cost of the complete pyrolysis system and energy recovery system was Rs. 9,25,000/-. The total cost of production per year with repair and maintenance is Rs. 9,11,650. Contd....