Study On Sorption Characteristic Of CO₂with Alkali Metal Based Sorbent Using Bentonite As The Supporter

Solid sorbents were combined with the characteristics of chemical absorption method and adsorption separation method, through solidifying the liquid sorbent and loading it on porous carrier. Solid alkali metal-based sorbents for CO2capture through CO2react with K2CO3/Na2CO3. Solid sorbent has high circulation efficiency and excellent absorbing capacity, in addition it has simple preparation processes, low energy consumption and no secondary pollution. In brief, this method shows great promise in terms of CO2capture.Using bentonite as the supporter and KHCO3as precursor, the potassium-based solid sorbents used in this study were prepared by spray-drying methods. The sorbent has a size distribution of0.6-180μm, and a bulk density of1.73g-mL-1. The sorbent was used to absorb CO2and through laboratory simulation of fixed bed device CO2sorption mechanism and the reaction characteristics were investigated. During several continuous operations, the parameters such as loading amount, carbonation temperature, sorption reaction time and aspect ratio of the bed were used to evaluate CO2absorption efficiencies of potassium-based solid sorbent. The mechanism of carbon dioxide absorbed by potassium-based solid sorbent was analyzed.In addition, NaHCO3were employed as precursor to manufacture sodium-based sorbent and compared its carbonation characteristics with potassium-based sorbent. The structure identification and carbonation characteristics of the solid potassium-based sorbent for CO2capture have been investigated with X-ray diffraction, gas adsorption method (BET)and scanning electron microscopy. The experimental results show that either potassium-based or sodium-based sorbent has a high CO2absorption efficiency, especially potassium-based sorbent has a higher rate of carbonation reaction.Different processes and methods will influence the sorption capacity. The CO2absorption efficiency of potassium-based sorbent did not diminish during multiple continuous operations, and within60-80℃potassium-based sorbent has an excellent CO2absorption efficiency. Results indicate that the carbonation conversion ratio for potassium-based sorbents could arrive84.8%during10sorption reaction cycles, and it shows excellent carbonation and regeneration capacity, and the maximum sorption capacity of CO2with potassium-based sorbents is115.3mg/g when the concentration of impregnation solution is23.1%and K2CO3loading amount is43.8%. Comparing with other capture technologies this method is more energy-efficient and lower cost, and shows great promise in terms of CO2capture.