Material conversion from used oil sorbents by pyrolysis

A lab-prepared cellulosic oil sorbent—used for oil spill cleanup—was pyrolyzed in a quartz, pipe-type horizontal furnace at different temperatures to recover energy and material. Model sorbent was exposed to different oils (diesel and two different motor oils) to simulate oil spill cleanup prior to pyrolysis. The pyrolysis products were analyzed using gas chromatography–mass spectrometry, Fourier transform infrared spectroscopy, and elemental analysis. The highest liquid yield of 85% was obtained at 500 °C for sorbent with 10W30 motor oil. Produced oils were two-phase immiscible liquids having different physico-chemical properties. Upper phases of the oils contain basic paraffinic groups, such as hexadecane, tridecane, tetradecane, pentadecane, octadecane, nonadecane, and heptadecane, while lower phases contain mainly carboxylic acid, aldehydes, ketones, and furan groups. Carbon content and energy value of the upper phases were higher than lower phase liquids. Char yields ranged between 6.5 and 29.1%, highest of which is the sorbent with no oil. Char from sorbent with 10W30 motor oil has the highest C/H ratio (16.20) and highest (31.5 MJ/kg) calorific value. Results indicate that pyrolysis can be an alternative for converting oil sorbents to value-added end products that can be used in electricity production, as chemical feedstock, medical products, or fuel additives.