FEATURES OF RECEIVING THE GASOLINE FRACTION BY THERMAL PYROLYSIS OF POLYOLEFIN RAW MATERIALS

Abstract

The article examines the peculiarities of the process of thermal pyrolysis of secondary polymer raw materials, aimed at obtaining a gasoline fraction - the basis for obtaining mixed or synthetic automobile gasoline. Based on the global experience of polymer processing, polyolefins represented by high-density polyethylene (HDLP) and polypropylene (PP) were chosen for the study. Thermal pyrolysis was carried out at atmospheric pressure (0.10-0.12 MPa) on a reactor-type laboratory installation with subsequent removal of the gasoline fraction (30-210 °C) from liquid pyrolysis products according to the ASTM D 86 method. It has been established that the temperature interval in which pyrolysis of polyolefin raw materials must be carried out is for HDLP - 400-430 °С (the maximum output of the gasoline fraction at 420 °С); for PP - 350-370 °C (maximum yield of gasoline fraction at 365 °C). By controlling the duration of thermal pyrolysis, it is possible to increase the yield of the gasoline fraction by an average of 15-17%, which must be taken into account during the industrial implementation and further operation of pyrolysis plants for polymer raw materials. Increasing the temperature of the end of boiling of the gasoline fraction from 150 °С to 210 °С allows to increase its output by 9% (for HDLP) and by 12% (for PP). But at the same time, there is also an increase in the content of olefins in it (by 13-14%), which is a positive point from the point of view of resistance to detonation of the gasoline fraction, and a negative point - in view of its low chemical stability. The conducted studies showed that secondary polyolefin raw materials should be considered as an alternative to classic raw materials (oil and gas condensate), and the pyrolysis process as the main technological process for obtaining the gasoline fraction - the basis for obtaining commercial automobile gasoline. Prospective places for the implementation of this technology are both production sites of oil refineries and sites located in close proximity to places of accumulation of raw materials - ports, city landfills, special landfills.