Abstract
From a viewpoint of used tires recycling, their pyrolytic conversion into an adsorbent with co-production of gaseous fuels was examined. Crushed used truck tread with diameter of 3mm or less was mixed with potassium hydroxide, and the mixture was cracked under a flow of argon in a thermobalance or a gas flow continuous reaction apparatus. The resulting char was characterized in terms of CHO composition, specific surface area, and absorptive activity. The co-produced gases and liquids were subjected to gas and gel permeation chromatographic analyses to determine the composition and the average molecular weight (Mw), respectively. Sulfur content was measured for all the products. The presence of potassium hydroxide resulted in both increases of gas and char yields with decrease of a tarry product. This implied promoted cracking of tar by potassium hydroxide, although Mw of the remaining tar was increased. More amount of the alkali led to more productions of hydrogen and methane with less evolution of carbon monoxide and dioxide. Also, it allowed the obtained char to have a larger ability of absorption and a smaller content of sulfur. Sulfur contained in tar was likewise decreased with increasing the amount of potassium hydroxide. These results indicated that this system of thermal cracking would be a promising means for re-utilization of used tires.
