Conversion of refuse derived fuel from municipal solid waste into valuable chemicals using advanced thermo-chemical process

Abstract

In this study, thermo-chemical decomposition of Refuse Derived Fuel (RDF) from municipal solid waste pre-treatment plant has been conducted in pyrolytic conditions. Due to high heterogeneity, individual RDF samples are not necessarily representative of the full variety of different components present. To overcome this, five different samples of RDF with varying compositions were treated in a rotary kiln reactor. RDF feed has been characterized based on the amount of biomass and plastic content. Product (oil & char) composition and quality were analysed using different characterization techniques. It was observed that the quality of pyrolysis products varied with the feed composition and operating temperature. Maximum oil yield of oil ∼43% was obtained from RDF containing ∼77% of plastics at 500 °C. This study showed that the interaction of RDF components has a major role in the pyrolysis oil composition. The oil phase mainly consisted of n-aliphatic, branched aliphatic compounds and primary alcohols while, the aqueous phase consisted of organic acids, furans, methanol, phenols, and their derivatives along with ketones. At higher temperatures, the phenolic compounds decreased and the alcohol content was found to increase. Using solvent extraction, phenolic compounds were extracted with hexane while, ketones and acids were extracted using acetone. With high plastic content (∼85%), the char yield reduced from 55% to 30% with increase in temperature. Char samples consisted of different functional groups such as –OH and –COOH along with the micronutrients such as K, Mg and P, with pH in the range of 7.8–9.5 making it suitable for soil applications. Detailed chemical composition analysis of pyrolysis oil and char is the key to design pyrolysis process and evaluating its importance for producing the value-added chemicals.