Experimental evaluation on pyrolysis and gasification characteristics of simulated waste cation exchange resin

• Published in: Journal of thermal analysis and calorimetry 2024, Vol.149 (19), p.10965-10982
• Main Authors: Liu, Zhiyuan, Chen, Meiqian, Li, Bingyang
• Format: Article
• Language: English
• Subjects: Analytical Chemistry; Cation exchanging; Cationic polymerization; Chemistry; Chemistry and Materials Science; Copolymers; Decomposition reactions; Gasification; Inorganic Chemistry; Measurement Science and Instrumentation; Nitrogen; Nuclear power plants; Nuclides; Oxygen; Physical Chemistry; Polymer Sciences; Pyrolysis; Resins; Sulfur; Thermogravimetric analysis
• ISSN: 1388-6150; 1588-2926
• DOI: 10.1007/s10973-024-13060-4

The safe disposal of large irradiated cation exchange resin waste in nuclear power plant has drawn worldwide attention. The kinetic characteristics and product characteristics of the simulated spent cation exchange resin in the pyrolysis and gasification were evaluated based on thermogravimetric analysis as well as TG-FTIR and TG-GC/MS. The temperature ranges at different decomposition stages of the resins were determined. In nitrogen atmosphere, the metal nuclides would hinder the reaction of waste resin in the first stage and promote the reaction in the second stage. The second-order reaction model was the best one to describe the kinetic mechanism in the first and second stages of the spent resins in different atmospheres, while Mample Power model ( n  = 1) and two-dimensional shrinking cylinder model were for the third gasification stage of the waste resins in 10 % oxygen atmosphere and 10 % steam atmosphere, respectively. The average mass loss ratio of the waste resin in 10 % oxygen atmosphere almost reached to 90 % that was higher than in 10 % steam atmosphere (80 %) and much higher than in nitrogen atmosphere (55 %). The initial reaction temperature in the third stage in 10 % oxygen was about 100 °C earlier than that in 10 % steam atmosphere, indicating that the sulfur bond would easily break due to the strong oxidization action of the oxygen. In the nitrogen atmosphere, the sulfur bond broke at 700 °C, which would lead to low mass loss ratio of the waste resin since the copolymer matrix is difficult to decompose. This work could supply basic data for the pyrolysis and gasification treatment of irradiated spent cation exchange resin in nuclear power plant.