The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors, especially its organic chlorine content. In this paper, experimental study of hydrothermal tre...The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors, especially its organic chlorine content. In this paper, experimental study of hydrothermal treatment on mixed plastic waste using the mixture of polypropylene, polystyrene, polyethylene and polyvinyl chloride （PVC） has been performed to observe the dechlorination effect of hydrothermal treatment on the waste. The system was generally applying saturated steam at around 2.4 MPa in a stirring reactor for about 90 minutes. After undergoing the process, the organic chlorine in treated plastic waste was reduced to 1,700 ppm level while the inorganic chlorine content was increased, suggesting an organic chlorine conversion phenomenon to inorganic chlorine, accompanied with low pH due to dehydrochlorination process. Additional limestone （Ca（OH）2） in subsequent experiment showed that the similar phenomenon was occurred but with higher pH and lower chlorine content in the condensed water, suggesting the production of inorganic salt rather than hydrochloric acid. Laboratory scale experiment was also performed to confirm the dechlorination phenomena especially for PVC, and the result showed that the main parameter which affected the dechlorination phenomena was the amount of water in hydrothermal process rather than limestone addition. It is suggested that a combination ofhydrothermal process and alkali addition would produce a low-chlorine solid product from plastic waste, promoting its usage as alternative solid fuel.展开更多
文摘The usage of plastic-impregnated waste derived solid fuel in conventional combustor is hindered by many technical factors, especially its organic chlorine content. In this paper, experimental study of hydrothermal treatment on mixed plastic waste using the mixture of polypropylene, polystyrene, polyethylene and polyvinyl chloride （PVC） has been performed to observe the dechlorination effect of hydrothermal treatment on the waste. The system was generally applying saturated steam at around 2.4 MPa in a stirring reactor for about 90 minutes. After undergoing the process, the organic chlorine in treated plastic waste was reduced to 1,700 ppm level while the inorganic chlorine content was increased, suggesting an organic chlorine conversion phenomenon to inorganic chlorine, accompanied with low pH due to dehydrochlorination process. Additional limestone （Ca（OH）2） in subsequent experiment showed that the similar phenomenon was occurred but with higher pH and lower chlorine content in the condensed water, suggesting the production of inorganic salt rather than hydrochloric acid. Laboratory scale experiment was also performed to confirm the dechlorination phenomena especially for PVC, and the result showed that the main parameter which affected the dechlorination phenomena was the amount of water in hydrothermal process rather than limestone addition. It is suggested that a combination ofhydrothermal process and alkali addition would produce a low-chlorine solid product from plastic waste, promoting its usage as alternative solid fuel.
