Elucidating the Solid, Liquid, and Gaseous Products from Batch Pyrolysis of Cotton Gin Trash

Abstract

Cotton gin trash (CGT) was pyrolyzed at different temperatures (500°C, 600°C, 700°C, and 800°C) using an externally heated batch reactor. The average yields of output products (solid/char, liquid/bio-oil, and gas) were determined. The heating value (HV) of CGT was measured to be around 15.5 MJ kg-1. Gas yield increased while char yield decreased as temperature was increased. The maximum char yield of 38 wt% was obtained after 30 min of pyrolysis at 500°C. The char had the largest fraction of the energy output (44% to 51%), followed by gas (6% to 15%) and bio-oil (4% to 5%). The maximum gas yield of 35 wt% was observed at 800°C. The average yield of CO, H2, and total hydrocarbons (THC) generally increased with increased temperature, while CO2 production decreased. Methane, ethane, and propane were the dominant constituents of the THC. The highest bio-oil yield of about 30 wt% was observed at 600°C. The HV of bio-oil was low (2 to 3 MJ kg-1) due to minimal non-hydrocarbon compounds and high moisture content (MC). The heating value of the organic portion of the bio-oil was measured to be 6.1 MJ kg-1.