Continuous CO2 capture in a circulating fluidized bed using supported amine sorbents

Abstract

In this work, supported amine sorbents were prepared by physical impregnation of silica and polymethylmethacrylate (PMMA) with tetraethylenepentamine (TEPA) and studied for post-combustion CO2 capture purposes in a lab scale circulating fluidized bed (CFB) reactor. Sorbent amine loading and support pore size effects were investigated by thermal gravimetric analysis (TGA). The sorbent CO2 capacity was found to be a strong function of amine loading and pore volume. Significant improvement of the sorbent CO2 adsorption capacity (3.5molkg−1) was achieved by tuning these variables. From preliminary testing of the fluidization behavior of PMMA based sorbent particles, it was found that, at high desorber temperatures, these sorbent particles formed aggregates plugging the reactor. This underlines the importance of not only evaluating sorbent capacity but also fluidization behavior in an early stage of process development. Continuous CO2 capture was demonstrated applying the developed silica based sorbent particles in the CFB reactor. Here, CO2 was captured from dry simulated flue gas applying a temperature difference of only 70°C between the adsorber column (40°C) and the desorber column (110°C). To the best of our knowledge this was the first time, a high (90%) purity CO2 product gas was produced at the regenerator outlet in continuous mode using these supported amine sorbents.