Desorption Kinetics of the Monoethanolamine/Macroporous TiO2-Based CO2 Separation Process

作者：Sun Zhuoyan; Fan Maohong^*; Argyle Morris

来源：Energy & Fuels, 2011, 25(7): 2988-2996.

DOI：10.1021/ef200556j

Monoethanolamine (MEA)/macroporous TiO2 sorbent is a promising material for CO2 separation because of its low energy demand. Similar to other CO2 separation technologies, CO2 desorption from the MEA/macroporous TiO2 sorbent is the most energy-intensive step in the overall CO2 separation process. The presence of water during the CO2 desorption process leads to a significant increase in energy consumption. Therefore, CO2 desorption in the absence of water is an important method to reduce energy consumption of CO2 separation using MEA/macroporous TiO2, which is determined by several major factors, including desorption kinetics. However, the study on CO2 desorption kinetics of supported MEA is lacking. This research was designed to make progress in this area. The CO2 desorption kinetic model of the MEA/macroporous TiO2 sorbent is experimentally derived with the data collected within the water-free desorption environment and theoretically proven by the pseudo-steady-state theory. The Avrami-Erofeyev mechanism controls the CO2 desorption process, which is first-order with respect to RNH3+RNHCOO-, RNH3+, or RNHCOO-. The activation energy of the CO2 desorption process is 80.79 kJ/mol. The kinetic characteristics of the CO2 desorption are much superior to those associated with aqueous MEA-based CO2 separation. The energy savings because of the use of MEA/macroporous TiO2 for CO2 separation not only results from avoiding the use of water, with its high specific heat capacity and high vaporization enthalpy, but also from the favorable desorption kinetics of the MEA/macroporous TiO2-based CO2 separation.

• 出版日期2011-7