Evaluation of Pyrolysis Products of Plastics and Coal

Abstract

Coke for iron-making is produced by pyrolysis of coals in coke oven. COG (Coke Oven Gas) by carbonizing is used as energy source in steel works. Waste plastics recycling process using coke ovens is mixed with coals and carbonized in coke oven. Though the process is in operation, the effect to COG is still uncertain.
Then first, in order to identify secondary decomposition of pyrolysis products of plastics such as light oil, tar, and gas and analyze more intimate behavior of plastics during pyrolysis, experimental system which has warm-up part for primary decomposition and heating part for secondary decomposition was developed. This experimental system has a Fourier transform-infrared spectrometer (FT-IR) as detector and can monitor the several kinds of gases, such as hydrocarbons, CO and CO₂ simultaneously, continuously and simply. Secondly, behavior of secondary pyrolysis of plastics was analyzed. Finally, behavior of pyrolysis of mixed sample composed by plastics and coals was analyzed and each pyrolysis product was evaluated on enrichment of calory.
In consequence, this paper reports that gas process of evolution, amounts of evolved gases, and compositions of evolved gases have additive property. Thus, there is no effect by mixing plastics resulting from the evolved gases during pyrolysis.