Easy fabrication method of Li4SiO4-K2CO3 based pellets for CO2 capture at high temperature

Abstract

This study focuses on a novel fabrication method of K2CO3-Li4SiO4 based sorbents for CO2 capture from hot flue gas of gas turbines. The developed pellets were produced by sintering K2CO3-Li4SiO4 powders at 550 °C using viscous polyalphaolefins as pore formers. This mild calcination temperature was selected as the optimal condition for the development of a suitable porosity preventing powder degradation which typically occurs at higher temperatures. The sorption/desorption performance was tested by thermogravimetric analysis conducted at 580 °C under 0.04 atm of CO2 and 620 °C under 1 atm of N2, respectively. Results showed that the use of 20 wt% K2CO3 represents the optimal content to achieve a stable formation of molten eutectic K2CO3-Li2CO3 mixture during CO2 chemisorption, while avoiding K2CO3 crystals phase segregation during multiple sorption cycles. In addition, the use of 30 wt% olefin allowed the development of resistant and porous pellets of tuneable dimension and shape with a stable sorption capacity up to 130 mgCO2/g obtained over 25 multiple cycles of 30 min each. The present research lays the groundwork for the adoption of a novel pelletizing technique to produce innovative sorbents with enhanced CO2 capture and cycling capabilities, manufactured via a simple and more sustainable approach.