Evaluation of the capacity of adsorption CO2 in commercial zeolites on pilot plant
Multi-scale and/or multi-disciplinary approach to process-product innovation
Analysis of Environmental Issues (T3-3b)
Keywords: zeolite, adsorption, PSA
The technology for the separation of CO2 from industrial gaseous streams through monocomponent adsorption has lately been used as an efficient process of obtaining high purity CO2, particularly after the recent development of new adsorbents, although further research on zeolite adsorption capacity and operating conditions is needed. This research study is concerned with the capacity of CO2 adsorption on commercial zeolites in a Pressure Swing Adsorption (PSA) pilot-plant.
The commercial zeolites tested (5A and 13X) have been selected due to their high CO2 adsorption capacity, as already shown in previous research work already reported in scientific literature.
The determination of the equilibrium CO2 adsorption capacity of these adsorbents has been carried out through gravimetry. The experimental apparatus involved mass flow meters, an adapted mufle and a high precision microscale. The results have shown that zeolite 13X has a greater CO2 adsorption capacity than zeolite 5A. The isotherms obtained for both zeolites were adjusted to the models proposed by Langmuir, Freundlich and Tóth and have shown a particularly good agreement to the Langmuir model. The equilibrium isotherm for zeolite 13X has then been used to determine the optimum operating conditions for the PSA pilot-plant, with regard to temperature and adsorbent moisture content, so as to maximize CO2 adsorption.
The breakthrough experiments in the PSA pilot-plant, using zeolite 13X as adsorbent, have been undertaken at 300.15 K and flow rate of 3.0 mL/min, for a gaseous mixture containing 11,5 % CO2, 87,5 % N2 and 1.0 % O2. Results indicate an adsorption capacity of 10.38 g of CO2 / 100 g of adsorbent. This is in agreement with the equilibrium adsorption isotherms obtained through gravimetry (10.4 g of CO2 / 100 g of adsorbent), and shows that at, these operating conditions, the adsorption of CO2 in the PSA pilot-plant is very close to equilibrium.
Presented Tuesday 18, 09:45 to 10:05, in session Analysis of Environmental Issues (T3-3b).
