Performance evaluation of natural draft based agricultural residues charcoal system

A natural draft based agricultural residues charcoal reactor has been described herein along with its performance details. Instead of releasing pyrogases into the atmosphere, these gases are burnt inside the charcoal reactor, offering better energy efficiency and environmental acceptability. Agricultural residues like arhar stalks (Cajanus cajan), saw mill woody waste, Ipomoea (Ipomoea fistulasa, Syn. Ipomoea Carnea) and babul wood (Acacia nilotica), all sun dried, were used as the feedstocks for charcoal making. Saleable charcoal (SC) yield was in the range of 28 to 47% dry basis (db) with the maximum from saw mill woody waste and the minimum from Ipomoea. Fixed carbon (FC) content in the SC varies from 69 to 77% (db) in the agricultural residues based charcoal. Babul wood charring gave the highest SC yield (50%, db) and the best quality charcoal in terms of FC (80%, db). Economic analysis revealed that if the system developed was operated annually for 4000 h, the user could have a net profit of around Rs.1,00,000/– (US $2500).