Adsorption Properties of Modified Soda Lime for Carbon Dioxide Removal within the Closed Environment of a Coal Mine Refuge Chamber

In coal mine safety, providing and maintaining a safe closed environment and reducing the casualties of coal mine disasters are a long-term challenges. A novel and modified soda lime with higher adsorption rate and capacity was developed through analyzing the reaction mechanism and adsorption factors. The best combinations of soda lime with different mass fraction is additives 6%, H2O 12%, and NAOH 6%, while the best working modes is 25 W fan power, 8 cm thickness, and S-5 soda lime according to the multi-index orthogonal experiment. The order of influence for CO2 adsorption rate of different compositions (mass fraction) is NaOH > H2O > Al2O3, and the order of influence in different working modes is fan power > thickness > the type of soda lime. Through the optimization design, the novel soda lime is easy to form without binding together in the process of adsorption for CO2 and the dust outflow reduced by about 50%. The adsorption rate still remain at a high level in a high temperature and high humidity environment (humidity 70% and temperature 30 °C). It was demonstrated that the adsorption capacity increased by 28%, the adsorption rate increased by 32.2%, and the power consumption reduced by 33.3%.