Comparison of Regeneration Energy, Solvent Loss and Cyclic Capacity of Different Solvents

https://doi.org/10.3390/pr9122184

“In addition to regeneration energy, this work also compares the solvent loss and cyclic capacity of each solvent to comprehensively evaluate the economic performance of the solvent. During the operation process, each solvent will have varying degrees of loss as the solution volatilizes in the desorption tower. If the ratio of the loss to the solvent in solution is too large, the concentration of the solution will be diluted. Therefore, it is necessary to constantly replenish the solvent, which increases the cost of the solvent and reduces the economic efficiency of the technology. Therefore, the lower the ratio, the better the economy of the solvent. It can be seen from Table 3 that the solvent with the lowest ratio is HEPZ, which is 0.02%. The operating temperature of the desorption tower in this process is 123–125 °C. HEPZ has the highest boiling point, so it is the least volatile. 1-MPZ and DMEA have the highest loss ratios because their boiling points are the lowest. In actual operation, the temperature of the desorption tower may be higher. If it exceeds 130 °C, the economic cost for solvent loss will be greater. Therefore, HEPZ has obvious advantages. The cyclic capacity shows the amount of CO₂ absorbed by the circulation per kilogram of solution. As a sterically hindered amine, the cyclic capacity of AMP is the highest, which is consistent with the initial theory. The cyclic capacity of HEPZ is 47% lower than AMP, but 64.7% higher than PZ and 21.6% lower than the primary amine MEA. Considering the absorption rate PZ > HEPZ > MEA [33], the economic value of HEPZ as a promotor will be significantly better than MEA and PZ. HEPZ can replace PZ and MEA as an absorbent to configure a mixed amine system with sterically hindered amine AMP. It is expected to be superior to the AMP/PZ system and has value for conducting pilot studies.”