Vacuum pyrolysis of commingled plastics containing PVC II. Product analysis

Citation
R. Miranda et al., Vacuum pyrolysis of commingled plastics containing PVC II. Product analysis, POLYM DEGR, 73(1), 2001, pp. 47-67
Citations number
54
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Organic Chemistry/Polymer Science
Journal title
POLYMER DEGRADATION AND STABILITY
ISSN journal
0141-3910 → ACNP
Volume
73
Issue
1
Year of publication
2001
Pages
47 - 67
Database
ISI
SICI code
0141-3910(2001)73:1<47:VPOCPC>2.0.ZU;2-5
Abstract
Vacuum pyrolysis of individual plastics including high density polyethylene (HDPE), low density polyethylene (LDPE), polypropylene (PP) and polystyren e (PS) has been performed at a final temperature of 500 degreesC and under a total pressure of 2 kPa. A PVC sample and a commingled plastic sample com posed of HDPE/LDPE/PP/PS/PVC have been pyrolyzed in two consecutive steps a t 360 and 520 degreesC in order to separately trap HCl. A pyrolysis set-up consisting of a bench scale batch reactor with a condensation train was use d to collect the pyrolysis products. The main gaseous and liquid products, including the chlorinated hydrocarbons, were identified by chromatography. Global and chlorine mass balances were performed. The yields and pyrolysis product composition from each single polymer were compared with those from the commingled plastics. At 520 degreesC, 99.55 wt.% of the total chlorine was trapped as HCl corresponding to 4.6 wt.% in yield, on an original feeds tock basis, followed by 62.0 wt.% wax, 31.1 wt.% oil, 1.0 wt.% gas and 1.2 wt.% solid char residue (loss was 0.1 wt.%). The pyrolysis oil contained 12 ppm Cl on a pyrolysis oil basis. This value was less than what was expecte d (153 ppm) from the theoretical values which were calculated when the indi vidual polymers were pyrolysed. The chlorinated hydrocarbons formed during the pyrolysis of commingled plastics were different from those obtained dur ing the thermal decomposition of pure PVC. However, the hydrocarbons produc ed in the oil fraction were similar to those identified during the pyrolysi s of the single plastics. (C) 2001 Elsevier Science Ltd. All rights reserve d.