@article{oai:kansai-u.repo.nii.ac.jp:00011783,
 author = {Ikenaga, Naoki and Miyamura, Yoshinari and Suzuki, Toshimitsu},
 journal = {関西大学工学研究報告 = Technology reports of the Kansai University},
 month = {Mar},
 note = {As a part of the recycling of waste plastics, degradation of polyethylene to ethylene and propylene with HZSM-5 catalyst was studied by using a two-step process (thermal cracking and catalytic cracking). In the first stage, thermal cracking of high density polyethylene (HDPE) was carried out at 450-500℃. Yields of the cracked oil from HDPE were 79% at 450℃ and 88% at 500℃, respectively. Hydrocarbons of C7-C20 were the predominant products in the cracked oil. Higher hydrocarbons (>C20) increased with increasing reaction temperature. In the second stage, in order to obtain lower alkenes (mainly C_2H_4 and C_3H_6), the catalytic cracking of the thermally-cracked oil obtained in the first stage was carried out using a HZSM-5 catalyst at 600℃ in N_2 and CO_2 atmospheres. Since the cracked oil was difficult to handle, n-C_<16>H_<34>, which was a representative product in the thermal cracking of HDPE, was employed as a model compound. HZSM-5 catalyst increased the C1-C4 gas yield to 50% and C_2H_4 + C_3H_6 yield to 12% in N_2 atmosphere. On the other hand, in CO_2 atmosphere the gas yield reached 61% and C_2H_4 + C_3H_6 yield reached 30%, respectively. Addition of CO_2 promoted the catalytic cracking of n-C_<16>H_^<34> with HZSM-5 to give C_2H_4 + C_3H_6.},
 pages = {53--62},
 title = {Promoting Effext of CO2 on the Degradation of Polyethylene to Ethylene and Propylene Over HZSM-5 Catalyst},
 volume = {48},
 year = {2006}
}