Enhancement of CO ₂ absorption in aqueous diethanolamine amine using microchannel contactors

Carbon dioxide (CO ₂) is the largest volume contributor and the fastest growing component of greenhouse gases. Based on current technology the only commercially available process that can absorb a reasonable amount of CO ₂ from flue gases is chemical absorption. The other techniques are generally less energy efficient and more expensive. MicroChannel technology can be used to enhance the mass transfer rate by increasing surface-to-volume ratio and improving the thermal controllability of the absorption process. In the current study we investigated the performance of microchannel contactors for absorption of CO ₂ in aqueous diethanolamine (DEA). A series of experiments was performed to measure CO ₂ absorption rate and removal efficiency for various gas-to-amine flow rate ratios. The rate of absorption was determined based on the variation of electrical conductivity of the aqueous DEA due to the CO ₂ absorption process. The effect of contactor length was studied for 200, 500, and 800 mm long microchannels. The pressure drops of two-phase flow for various flow rate ratios and microchannel length were measured. The results demonstrated high potential of the microchannel contactors for enhancement of the absorption process.