摘要
Abstract
The TRPO process is a treatment methodology for high-level waste liquid that has been independently developed in China.This process uses TRPO as an extractant to remove long-lived isotopes such as transuranic elements and highly toxic isotopes such as strontium and cesium from high-level waste liquid.However,TRPO undergoes a series of physical and chemical changes after irradiation,resulting in a decrease in quality and affecting extraction performance.Nevertheless traditional alkali washing and water washing methods are ineffective in removing the strong complex products generated by irradiation in TRPO.Consequently,the issue of retention of heavy metal nuclides,such as plutonium,resulting from these strong complex products cannot be adequately addressed through alkali and water washing alone.To significantly reduce both the costs and the volume of radioactive waste,it is essential to purify the dirty TRPO solvent generated during this process for potential reuse.The resin-fixed bed is emerged as an effective approach for purifying the dirty TRPO solvent.When designing a resin-fixed bed,it is necessary to accurately determine the penetration time under varying operational conditions.However,the high-level radioactivity poses a challenge in acquiring a sufficient quantity of radiation-degraded dirty solvents,making it difficult to ascertain penetration times through extensive testing.To address this challenge,a differential bed technique was employed utilizing a minimal amount of radiation-degraded dirty solvent.Through limited experimental trials,key thermodynamic and kinetic parameters for resin purification adsorption were determined,specifically the resin adsorption equilibrium curve and the mass transfer coefficient of the adsorption process.Based on these parameters,a mass transfer model for resin-fixed beds adsorption was established,through which a series of pentration curves were obtained.Furthermore,a mass transfer model available for resin-fixed beds was established,which facilitates the generation of penetration curves.The effects of resin-fixed bed length,feed rate,and feed concentration on the dynamic evolution of resin-fixed bed adsorption and penetration time were systematically examined through a total of 120 simulations in this study.A linear relationship between penetration time(tp)and resin saturation adsorption time(ts)was determined which is tp=3.94ts-9.64×103.The resin adsorption saturation time can be calculated based on operational conditions.In addition,the adsorption equili-brium curve and the liquid-solid mass transfer coefficient can be expressed as q=8.017×10-4+0.1804co-7.390×10-3c2o+1.177×10-4 c3o and εKLa=-0.021+1.32U-5.56U2,respectively.The novel method proposed in this research offers a solution to circumvent radioactive limitations and rapidly determine penetration time of resin-fixed bed during the dirtty TRPO solvent purification.关键词
高放废液/TRPO净化/树脂吸附/固定床模拟/穿透时间/设计方程Key words
high-level waste liquid/TRPO purification/resin adsorption/fixed bed simulation/penetra-tion time/design equation分类
能源科技
