Effective absorption of SO2 by imidazole-based PILs with multiple active sites: Thermodynamic and mechanical studies

In view of the environmental hazards caused by SO2, the development of efficient SO2 capture technology has important practical significance. In this work, a low viscosity protic ionic liquids containing imidazole, ether linkage, and tertiary amine structure, was synthesized by acid-base neutralization of tris(3,6-dioxaheptyl)amine (TMEA) and imidazole (Im) for SO2 absorption. The results showed that the solubility of SO2 in [TMEA][Im] reached 12.754 mol·kg-1 at 298.2 K and 100 kPa and the ideal selectivity of SO2/CO2(1/1) and SO2/H2S(1/1) are 141.6 and 11.8 at 100 kPa, respectively. Furthermore, [TMEA][Im] can be reused and the SO2 absorption performance was not significantly reduced after five cycles. In addition, the absorption of low-concentration SO2 (2000 ppm) in [TMEA][Im] was also tested. Further spectroscopic research and thermodynamic analysis suggested that the high SO2 uptake by [TMEA][Im] was caused by the synergistic effect of physical and chemical absorption.

Limestone Sorbents Market for Flue Gas Desulphurisation in Coal-Fired Power Plants in the Context of the Transformation of the Power Industry—A Case of Poland

Since the beginning of the 1990s, due to international regulations on air quality, a large number of flue gas desulphurisation (FGD) installations have been constructed in the Polish coal-fired power industry. Thanks to that, SO2 capture in this industry increased to ca. 90%. Since wet lime or fluidized bed boilers were mostly used for FGD purposes, a significant increase in the domestic demand for lime sorbents has been reported. Between 1994 and 2019, it has increased from virtually zero before 1994 to about 3.3–3.4 million tpy (tonnes per year) today. On the basis of official governmental data and completed surveys of the Polish power companies, the paper analyses the process of the implementation of FGD in Poland along with limestone sorbents consumption and FGD gypsum production in the Polish coal-fired power plants. It also presents the current and potential limestone resource base for production of limestone sorbents applied in FGD. Electric energy mix in Poland is expected to be changed radically in the coming 30 years. Share of coal-based electricity is still very high—ca. 80%—and it will remain dominant for at least next decade. With the next coming FGD installations, further moderate increase of limestone sorbents consumption is expected, up to 3.7 million tpy in 2030. After 2030, a significant, quick decrease of share of coal-fired electricity is expected in Poland, down to max. 30% just before 2050. This will result in a gradual decrease in limestone sorbent demand, to max. 1.3 million tpy before 2050 and virtually zero after 2050, which will be followed by collapse of FGD gypsum production.