Synthesis and Characterization of Catalyst for Liquid Fuel Production from Polymer Waste

Abstract

Importance of alternate energy has been increasing day by day due to the rapid depletion of crude oil reserves. Besides, in developing countries as in Asia (where the waste management has been a problem), the potential of growth of plastic consumption is very high. Fuel from plastic serves the dual purpose of energy and waste management. Catalytic pyrolysis is so far the most suitable process among other physical and chemical methods that include land filling, mechanical recycling, biological recycling, thermal incineration, partial oxidation, depolymerization, hydro cracking and thermal cracking. One of the most commonly used solid catalysts in polymer degradation studies are zeolites due to their strong acidity, pore size and specific pore structure effects. Amongst the numerous kinds of zeolites investigated in polyolefin pyrolysis, the most commonly used are Beta, USY, ZSM- 11, REY, Mordenite, ZSM-5 etc. Some other solid acid catalysts used for plastic pyrolysis include molecular sieves, silica alumina, and MCM-41. Reports on the use of FCC catalysts are also found in literature. Other catalytic materials such as clays (montmorillonite, saponite), reforming catalysts, activated carbon, metal oxides, metal complexes of the type MCln-AlCl3 or M(AlCl4)n (M=Li, Na, K, Mg, Ca, Ba; n=1–2), and alkali metal carbonates or alkaline metal carbonates have also been tested for polymer degradation.This work was carried out to investigate the effect of temperature and degree of acid treatment of kaolin clay on catalytic cracking of plastic waste material (PP and mixed polymer waste). Untreated kaolin clay and acid treated kaolin clay were characterized by standard BET method and XRD. Product obtained was analyzed by GC-MS and FT-IR. Waste material was cracked thermally and catalytically in a batch reactor in the temperature range 350- 500°C for synthesis of liquid fuel. For this purpose, kaolin clay was first treated with different prepared molar solutions of HCl (1M, 3M and 5 M) under reflux condensation at 100°C and atmospheric pressure in a round bottom flask for 4 hours. Cracking activity of untreated kaolin clay was compared with acid treated kaolin clay. It was observed that acid treated kaolin clay performed better than untreated kaolin clay due to high surface area and greater number of acidic sites.