Adsorption Kinetics of Nano CaO Base CO2 Adsorbent

摘要

The paper concerns the CO2 adsorption kinetics of nano CaO based adsorbent at high temperatures. The experiments measuremented the CO2 adsorption ratio of the nano scale CaO (70 nm) and micro scale CaO (60-80 μ m) adsorbent respectively at the temperature of 500-650 ℃ by a TGA. ,and evaluated with an Avrami-Erofeeve kinetic equation ： ()()() ln1 n G x x kt ==, exp( ) E k A RT =. A new criterion 2 2 0 d x d t = has been proposed to divide reaction section and diffusion section. The simulation results showed that a relative deviation of CO2 adsorption ratio of the reaction section and diffusion section were lower than 3.5% and 0.86% respectively. The activity energy of reaction section of nano scale CaO is 11.9 kJ/mol. The activity energy of diffusion section of nano scale CaO is 106.9 kJ/mol. Nano scale CaO with a higher reaction constants and diffusion constants than the micrometer scale CaO under the temperatures of 500-650 ℃. This explains the reason of nano CaO base CO2 adsorbent has higher adsorption ratio and reaction rate than the micrometer scale CaO base adsorbent.