A Cu doped TiO2 catalyst mediated Catalytic Thermo Liquefaction (CTL) of polyolefinic plastic waste into hydrocarbon oil

Abstract

Plastic waste has been identified as a potent feedstock for liquefaction to produce hydrocarbon liquid oil (HC-Oil) by employing Catalytic Thermo Liquefaction (CTL). The resulting process for liquefaction of plastic was termed as Poly-Urja process and produced hydrocarbon oil was termed as HC-Oil. The CTL explores copper doped TiO2 (Cu@TiO2) catalyst as a selective, robust, non-toxic, inexpensive and promising material for liquefaction of polyolefinic plastic waste with minimum char and gas formation. The use of simple, non-expensive and non-complex co-precipitation method has provided a series of Cu@TiO2 catalysts with variable composition of the metal. Of the synthesized catalysts, Cu@TiO2 with 5% metal loading gave maximum conversion and yield of HC-Oil in laboratory batch reactor. The physicochemical and surface morphological properties of the catalyst were studied by using ATR-FTIR, XRD, SEM-EDX, BET and ICP-MS. Process intensification study was conducted to obtain maximum conversion and yield. The intensified CTL process gave >85% conversion and >80% yield of HC-Oil at less stringent conditions. HC-Oil is a carbon rich substrate comprises of 75–85% carbon, 5–15% hydrogen, 5–10% other elements and have a calorific value of ~42 MJ/kg thus it can be used for multiple applications of energy, fuels and chemicals etc. Physicochemical characterization of HC-Oil showed the presence of long and short; straight and branched chains of hydrocarbons (C8-C28). Moreover, CTL can convert any combination of plastic waste into HC-Oil with minimum carbon loss and >80% yield. Thus, the CTL process for polyolefinic waste provides an efficient, sustainable and environmentally friendly alternative to convert plastic waste into energy.