| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 642431 | Separation and Purification Technology | 2011 | 6 Pages |
Piperazine (PZ) and phosphates as additives were added into an aqueous N-methylmonoethanolamine (MMEA) to form complex absorbents, respectively. Performances of CO2 capture by the complex absorbents were evaluated in a bubble column reactor. Reaction mechanisms and activations of the additives were presented theoretically. Effects of type and concentration of additives, and gas flowrates on volumetric mass transfer coefficient were investigated, and effects of orifice size of the gas sparger and stirring rates on average absorption velocity were also discussed. Results show that CO2 loadings of MMEA–PZ and MMEA–K3PO4 complex absorbents were larger than that of single MMEA and MEA absorbents. The MMEA–PZ complex absorbent gave a highest CO2 loading in all complex absorbents. The overall mass transfer coefficient increased, subsequently reached a maximum and then decreased with the increase of K3PO4 concentration in the complex absorbent. The overall mass transfer coefficient increased with the increase of the gas flow rates. Average absorption velocities increased with the decrease of the orifice size and with the increase of the orifice numbers. The average absorption velocities in moderate intensity of stirring rates were higher than that in the high intensity of stirring rates.
► Two MMEA-based efficient complex absorbents were developed for CO2 capture. ► Activation scheme and mechanism were theoretically presented. ► A new theoretical expression for kLa calculation was developed. ► Effects of orifice parameter and stirring rate on CO2 capture were evaluated. ► Bubble coalescence led to a decrease of gas–liquid contact area.
