Fuels by Chemical Recycling of Waste Plastic and Biomass Mixture and Utilization of the Products

Abstract

Plastics are key tools in many sectors in our everyday life. In 2016, 320 Mt of plastic waste was generated worldwide and the volume is growing rapidly. In Europe, plastic production increases by 3 % - 5 % a year. Plastics appear in mixed form with other constituents of the waste bins. In one hand, many processes are available for the selection of the pieces by type; on the other hand, these steps need additional cost. The amount of annual biomass waste is around 3.5x109 t, which contain a huge amount of paper, cardboard, etc. Waste pyrolysis should be one possible option for high value-added, sustainable waste polymer and biomass recycling. During the pyrolysis valuable hydrocarbons could be obtained from waste streams. However, the long-term utilization of the products is an unsolved problem. This work is dedicated to the pyrolysis of plastic waste and biomass under mild conditions and investigation of the product properties by catalysts. For this purpose, synthetic zeolite catalysts were applied. It was concluded that the gas yields could be increased from 16.4 % to the range of 22.6 % - 32.2 % and to the range of 24.3 % - 29.4 % by using Ni/ZSM-5 and Ni/SAPO-11based catalyst mixture. The quality of oil produced by catalytic pyrolysis had favorable properties (lower C/H ratio, high mono-aromatic ration (13.9 % - 21.2 %); higher energy content, fewer contaminants or even better long-term properties) by the using of catalysts. Contaminants from raw materials move to gaseous and liquid fractions, and their level can decrease by catalysts.