Theoretical Study on Optimal Conditions for Absorbent Regeneration in CO2Absorption Process

The considerable portion of energy demand has been satisfied by the combustion of fossil fuel and the consequent emission was considered as a main cause of global warming. As a technology option for emission mitigation, absorption process has been used in capture from large scale emission sources. To set up optimal operating parameters in absorption and solvent regeneration units are important for the better performance of the whole absorption plant. Optimal operating parameters are usually selected through a lot of actual operation data. However theoretical approach are also useful because the arbitrary change of process parameters often limited for the stability of process operation. In this paper, a theoretical approach based on vapor-liquid equilibrium was proposed to estimate optimal operating conditions of absorption process. Two absorption processes using 12 wt% aqueous solution and 20 wt% aqueous MEA solution were investigated in this theoretical estimation of optimal operating conditions. The results showed that loading of rich absorbent should be kept below 0.4 in case of 12 wt% aqueous solution for absorption but there was no limitation of loading in case of 20 wt% aqueous MEA solution for absorption. The optimal regeneration temperature was determined by theoretical approach based on loadings of rich and lean absorbent, which determined to satisfy the amount of absorbed . The amount of heating medium at optimal regeneration temperature is also determined to meet the difference of loading between rich and lean absorbent. It could be confirmed that the theoretical approach, which accurately estimate the optimal regeneration conditions of lab scale absorption using 12 wt% aqueous solution could estimate those of 20 wt% aqueous MEA solution and could be used for the design and operation of absorption process using chemical absorbent.