Pathways of Chemical Recycling of Polyvinyl Chloride. Part 2
- PDF / 978,568 Bytes
- 46 Pages / 612 x 792 pts (letter) Page_size
- 69 Downloads / 190 Views
EWS
Pathways of Chemical Recycling of Polyvinyl Chloride. Part 2 E. M. Zakharyana,*, N. N. Petrukhinaa, E. G. Dzhabarova, and A. L. Maksimova,b a
Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, 119991 Russia b Chemical Faculty, Moscow State University, Moscow, 119991 Russia *e-mail: [email protected] Received July 3, 2020; revised July 21, 2020; accepted July 30, 2020
Abstract—The review deals with the hydrolysis of polyvinyl chloride waste in media of alkalis and organic bases and with the treatment of chlorine-containing waste in critical media (water, ammonia, methanol, carbon dioxide). The principles and mechanisms of the hydrodechlorination and hydroconversion of polyvinyl chloride/vacuum gas oil mixtures and of the gasification of polyvinyl chloride waste and municipal chlorinated plastic waste are described. Procedures for joint hydrothermal treatment and gasification of polyvinyl chloride waste with biomass and coal and various specific methods for polyvinyl chloride dechlorination are analyzed. The major advantage of hydrothermal treatment of polyvinyl chloride in subcritical water is that the products contain no chlorinated organic compounds. The major advantages of the dehydrochlorination of waste containing polyvinyl chloride are high degree of removal of organic chlorine and high H/C ratio in recycled products. Keywords: polyvinyl chloride, polyvinyl chloride waste, municipal plastic waste, dechlorination, hydrothermal treatment, critical media, biomass, hydrodechlorination, hydroconversion, gasification, joint recycling DOI: 10.1134/S1070427220100018
INTRODUCTION The need for recycling of chlorinated polymers is beyond doubt, but it is important to choose a proper recycling technology. This choice is influenced by the origin of the secondary resources (industrial or municipal waste), their purity, and commercial value of the recycling products. In [1], we considered the mechanochemical recycling of polyvinyl chloride, pyrolysis, and low-temperature catalytic dechlorination in the presence of metal oxides. These methods have a common drawback: formation of difficultly utilizable solid waste having no use, namely, of metal chlorides and chlorinated coke. Furthermore, liquid products of such processes often contain chlorinated compounds and require fining. In this review, we consider published data on recycling of chlorinated polymer waste to reveal the main trends in the development of dechlorination technologies, to analyze the dechlorination mechanism in various processes, and to evaluate prospects for producing monomers for chlorinated macromolecular compounds. In the second part of the review, we
analyzed environmentally safe approaches to polyvinyl chloride recycling to obtain chlorine-free liquid hydrocarbons: hydrolysis, treatment in sub- and supercritical water, ammonia, and methanol, joint hydrothermal treatment with biomass and coal, hydrodechlorination, gasification of polyvinyl chloride waste and municipal chlorinated plastic waste, and joint gasification of po
Data Loading...
