Estimating the efficiency of catalysts for catalytic pyrolysis of polyethylene

The paper is devoted to investigation of the catalytic pyrolysis of high-density polyethylene (PE) in the presence of HBEA, HZSM-5 and HFER catalysts and natural clay. Catalytic pyrolysis of plastic materials is a promising method for treatment of secondary raw materials because it allows converting polymers into chemical compounds, which further serve as a source for chemical industry. Physicochemical parameters of the catalysts were estimated using various methods: IR Fourier spectroscopy, X-ray diffraction analysis, physical adsorption of N2, thermogravimetric analysis, and pyrolytic gas chromatography. Temperature dependences of PE destruction were obtained as well as the dependence of chemical composition of the catalytic pyrolysis products on the catalyst type. Two main factors were shown to determine the efficiency of cracking and the qualitative composition of products – structural and acidic parameters of the catalyst. The presence of Broensted acid sites in zeolites promoted the cracking and aromatization reactions. The possibility of using the clay sample for thermal decomposition of PE was estimated.