CO_2 Absorption in an Absorber Column with a Series of Intercooler Circuits

摘要

This work proposes an improvement to the carbon dioxide (CO_2) absorption process for a natural-gas fired combined cycle gas turbine (CCGT) power plant by the integration of intercoolers along the absorption column height with different arrangements of intercooler circuits. The intercooler circuits arrangements are a leap-stage intercooler and a serpentine-stage intercooler circuits. A certain amount of hot stream is split out of the absorber to enter into a series of both circuits in order to lower the absorber temperature. These two processes significantly reduce the temperature resulting from the exothermic heat of the chemical reaction between chemical absorbent and CO_2. The low temperature causes a reduction in Henry's law coefficient which subsequently increases the CO_2 capture capability. As a result, these allow improvements in mass transfer driving force, and in turn an increase of the solubility, all of which means an increase of CO_2 cyclic capacity. It is found that the reboiler heat duty of the leap-stage intercooler and a serpentine-stage intercooler are significantly decreased by 17% and 25%, respectively. Consequently, the CCGT's efficiency point drops of these two processes are reduced from 4.72% to 3.93% and 3.57%, respectively.