METHOD FOR DECOMPOSING POLYSTYRENE

摘要

PROBLEM TO BE SOLVED: To increase the recovery ratio of styrene monomer by raising the decomposition ratio and suppressing the side reactions of the styrene monomer when polystyrene is decomposed in high-temperature and high-pressure water. SOLUTION: This method is to decompose the polystyrene in the high- temperature and high-pressure water in a reactor. The temperature of the high- temperature and high-pressure water is 250-550 deg.C and the pressure thereof is the saturated steam pressure or above or the critical pressure or above at the temperature. An aqueous solution in which low-molecular compound components produced by the decomposition are dissolved therein is continuously led out to a region under conditions of a lower temperature than that in a decomposition reaction region while continuously feeding the high-temperature and high-pressure water to the reactor. Thereby, the time for the low-molecular compound component to stay in the decomposition reaction region is reduced.