چكيده به لاتين
The main objective of this work is to optimize the operating conditions of CO2 adsorption and regeneration by Sodium carbonate adsorbent in a fixed bed reactor and optimize sorbent to improve adsorption capacity. Response surface methodology (RSM) was employed for optimization, using three temperature, H2O/CO2 mole ratio, and the vapor pretreatment time variables with initial adsorption capacity (Aci) and the deactivation rate constant of sorbent (kd) as the responses. Optimum conditions were introduced at the point where the initial adsorption capacity and deactivation rate constant of sorbent would be as high and low as possible, respectively.The optimum process variables obtained from the numerical optimization corresponded to 50°C, 1 and 9 min for the adsorption temperature, mole ratio of H2O/CO2, and vapor pretreatment time, respectively. The amounts of (Aci) and (kd) in these conditions were obtained 39.238 mgCO2/gsorbent and 0.416 min-1, respectively. In the sorbent optimization section, the physical properties of gamma alumina, such as the specific surface area and pore volume, and the effect of them on the adsorbent performance were investigated. A series of five mesoporous alumina supports were prepared by sol-gel method. The results showed that the specific surface area (344 m2/g) and the pore volume (2.2 cm3/g) of the best synthesis of alumina with a molar ratio of 0.05 polyethylene glycol to alkoxide compared to the synthesized sample in the absence of polyethylene glycol increased about 40 and 340%, respectively. It was also observed that with increasing molar ratio of polyethylene glycol to more than 0.05, no significant change was observed in the structure of alumina. In the next step, the best synthesized gamma gamma alumina was studied by nitrogen adsorption and dispersion analysis, scanning electron microscopy and X-ray diffraction. Subsequently, commercial gamma alumina prepared from Merck Co. with a specific surface area of 174 m2/g and a pore volume of 0.5 cm3/g Compared. The results show that by increasing the gamma alumina pore volume and specific surface area, the adsorption capacity of the sorbents increases. Then, the optimum loading of sodium carbonate on the best sorbent was introduced and the maximum total adsorption capacity obtained for the sodium carbonate supported by the synthesized alumina was 131.58 mgCO-2/gsorbent. The minimum temperature at which the adsorbent was completely regenerated was introduced using the TPD analysis of 300°C. It was shown that when sorbent is recovered at 300°C, the adsorption capacity does not change in four successive cycles.
Keywords: Optimization, Carbon dioxide adsorption, Sodium carbonate sorbent, Gamma alumina, Regeneration temperature
