Thermochemical emission and transformation of chlorinated paraffins in inert and oxidative atmospheres
2017
Xin, Shanzhi | Gao, Wei | Wang, Yawei | Jiang, Guibin
Chlorinated paraffins (CPs) generally function as flame retardants and plasticizers in various materials. They are most likely to be processed by thermal processes during the whole life cycle. However, data on the formation and emission of CPs during thermal processes are still not fully understood. In this study, we simulated industrial thermal processes to investigate the emission of medium-chain chlorinated paraffins (MCCPs) and short-chain chlorinated paraffins (SCCPs) using commercial CP52 as the feedstock. We found that CP52 decomposed very easily at 210–320 °C. The decomposition of CPs generated large quantities of MCCPs, SCCPs. They were remained in the residue at low temperature (∼200 °C) and were gradually released into the gas phase at increased temperatures. MCCPs and SCCPs were not detected in either the residue or the gas phase as the temperature exceeds 400 °C. However, significant concentrations of aromatic and chlorinated aromatic hydrocarbons (Cl-PAHs) were identified in the gas phase and they were formed as the amount of SCCPs and MCCPs diminished. Cl-PAHs were dominated by low chlorinated chlorobenzenes (CBz), polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs). Oxygen promoted the release and decomposition of SCCPs in the gas phase. The results of the present study revealed the release of MCCPs, SCCPs and their synergistic emission with Cl-PAHs when CPs was subjected to heat. This work may also provide data for developing techniques to control the emission of CPs and Cl-PAHs multiply.
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