Carbon Dioxide Capture under Low-Pressure Low-Temperature Conditions Using Shaped Recycled Fly Ash Particles

Carbon-capture technologies are extremely abundant, yet they have not been applied extensively worldwide due to their high cost and technological complexities. This research studies the ability of polymerized fly ash to capture carbon dioxide (CO₂) under low-pressure and low-temperature conditions via physical adsorption. The research also studies the ability to desorb CO₂ due to the high demand for CO₂ in different industries. The adsorption–desorption hysteresis was measured using infrared-sensor detection apparatus. The impact of the CO₂ injection rate for adsorption, helium injection rate for desorption, temperature, and fly ash contact surface area on the adsorption–desorption hysteresis was investigated. The results showed that change in the CO₂ injection rate had little impact on the variation in the adsorption capacity; for all CO₂ rate experiments, the adsorption reached more than 90% of the total available adsorption sites. Increasing the temperature caused the polymerized fly ash to expand, thus increasing the available adsorption sites, thus increasing the overall adsorption volume. At low helium rates, desorption was extremely lengthy which resulted in a delayed hysteresis response. This is not favorable since it has a negative impact on the adsorption–desorption cyclic rate. Based on the results, the polymerized fly ash proved to have a high CO₂ capture capability and thus can be applied for carbon-capture applications.