Energy & Fuels 2002, 16, 1251-1255
1251
Study on the Pressurized Hydrolysis Dechlorination of PVC Jun Lu,* Shibai Ma, and Jinsheng Gao Department of Chemical Engineering for Energy Resource, East China University of Science and Technology, Shanghai 200237, China Received February 25, 2002
The PVC pressurized hydrolysis dechlorination has been studied in an autoclave reactor under different operating conditions such as temperature, reaction time, and alkali concentration. About 95% of the chlorine in PVC can be effectively removed within 2 h at temperature 240 °C in hydrolysis process. The HCl yield increases and residue yield decreases with the increasing of hydrolysis temperature. The structure of residue was analyzed by using FTIR and SEM. It was found that the hydrolysis dechlorination process has advantages over the thermal decomposition of PVC.
Introduction The disposal of waste plastics has been recognized as a major environmental problem. Waste plastics are undesirable components for landfilling, since they are not biodegradable. Treatment of waste plastics by direct incineration is not very desirable due to increased greenhouse gas emission, primarily CO2, and other toxic pollutants. At the same time, waste plastics are regarded as an inexpensive and abundant source of chemicals and energy.1,2 The conversion of waste plastics into useful fuel oil has been considered as the most promising recycling method.3 In the case of waste plastics chemical recycling, PVC materials cause various problems. It is well-known that, during the thermal degradation of PVC, elimination of HCl occurs and leads to the formation of conjugated double bonds. The polar HCl molecule when liberated from PVC attacks the double bonds compounds leading to the production of chloroorganic compounds.4 These undesirable products can be prevented by dechlorination of PVC. For extensive dehydrochlorination, thermal degradation is not useful because secondary reactions, such as crosslinking, Diels-Alder reactions reduce the content of conjugated bonds as the reaction is carried out at high temperature.5,6 Although low temperatures (
