Experimental study on treatment of mixed ion exchange resins by supercritical water gasification

Nuclear power acts as a significant role in the current world energy supply system. The treatment of radioactive waste from nuclear station is a considerable issue and has attracted more and more attention. Spent ion exchange resins used in nuclear power plants are typical organic nuclear waste which are difficult to deal with. Super-critical water gasification could offer an efficient and clean treatment to spent ion exchange resins. In this study, Supercritical water gasification of mixed ion exchange resins was carried out in a batch reactor with various conditions. Effects of reaction parameters such as temperatures (550oC-750 degrees C), concentrations (5 wt%-15 wt%), catalysts (K2CO3, Na2CO3, KOH and NaOH) and residence times (10 min-60 min) were investigated. Results showed that high temperature, low concentration, K2CO3 addition and long residence time promote the gasifi-cation result. And the carbon gasification efficiency reached up to 97.2% with 10 wt% concentration and K2CO3 catalyst addition at 750 degrees C. The main intermediate organic component residues in liquid products were trime-thylamine, benzene, toluene, ethylbenzene p-xylene styrene benzene, 1-ethyl-4-methyl-and naphthalene. Re-action pathways in supercritical water have been discussed and proposed. And the conversion pathways and distributions of sulfur and nitrogen were disclosed.

Automated summary

Supercritical water gasification offers an efficient and clean treatment for spent ion exchange resins, with high temperature, low concentration, K2CO3 catalyst addition, and long residence time promoting the gasification result. The carbon gasification efficiency reached 97.2% at 750 degrees C with 10 wt% concentration and K2CO3 catalyst addition. The main organic component residues in the liquid products were identified, and the reaction pathways and distributions of sulfur and nitrogen were discussed.