Highly Efficient SO2 Absorption and Its Subsequent Utilization by Weak Base/Polyethylene Glycol Binary System
journal contributionposted on 05.02.2013, 00:00 by Zhen-Zhen Yang, Liang-Nian He, Ya-Nan Zhao, Bing Yu
A binary system consisting of polyethylene glycol (PEG, proton donor)/PEG-functionalized base with suitable basicity was developed for efficient gas desulfurization (GDS) and can be regarded as an alternative approach to circumvent the energy penalty problem in the GDS process. High capacity for SO2 capture up to 4.88 mol of SO2/mol of base was achieved even under low partial pressure of SO2. Furthermore, SO2 desorption runs smoothly under mild conditions (N2, 25 °C) and no significant drop in SO2 absorption was observed after five-successive absorption–desorption cycles. On the other hand, the absorbed SO2 by PEG150MeIm/PEG150, being considered as the activated form of SO2, can be directly transformed into value-added chemicals under mild conditions, thus eliminating the energy penalty for SO2 desorption and simultaneously realizing recycle of the absorbents. Thus, this SO2 capture and utilization (SCU) process offers an alternative way for GDS and potentially enables the SO2 conversion from flue gas to useful chemicals as a value-added process.