Synergistic Removal of SO_x and NO_x in CO₂ Compression and Purification in Oxy-Fuel Combustion Power Plant

Abstract

Oxy-fuel combustion is a carbon-reduction technology that can be utilized in coal-fired power plants. A compression and purification system is an important part of an oxy-fuel combustion power plant. This study aims to develop suitable technologies as well as equipment for CO 2 compression and purification for oxy-fuel combustion. A 300 t/a CO 2 compression and purification experimental system was designed. The proposed platform can be operated under good performance. The average desulfurization and denitration rates under different working conditions are more than 98%. Changes in the n(SO 2 ):n(NO x ) ratio exert limited effects on sulfur and nitrate purification. SO 2 can be partially oxidized into SO 3 under the pressurized atmosphere and the presence of O 2 and NO x . Moreover, SO 2 oxidation is promoted with pressure and the existence of H 2 O and NO x .

Simultaneous Absorption of NOx and SO2 into Water and Acids under High Pressures

“…The concentration of SO 2 gradually increased with time, and the concentrations of NO and NO 2 increased rapidly within 10 min and stabilized at 40 and 50 ppm, respectively. The reactions involved in the absorption of SO 2 into water includes () and (), − while the absorption of NO x into water includes ()–(). − The above absorption reactions () and () indicate that H + is produced and then affects the speciation of nitrogen and sulfur in liquid. Based on the pH measurement of the solution, after absorption for 5 min, the pH reached 4.00, and after absorption for 1 h, the pH reached 1.91.…”

Carbon Capture From Flue Gas and the Atmosphere: A Perspective

“…After WGS, the CO 2 concentration in the flue gas is relatively high, which is in the range of 15-60% (dry basis) at a total pressure of 2-7 MPa (Gazzani et al, 2013a;Gazzani et al, 2013b), thus physical solvents such as Selexol and Rectisol rather than chemical solvents are commonly used for precombustion capture. • Oxy-combustion is a relatively new technology (Jurado et al, 2015) and involves the combustion of fuel feedstocks in a nearly pure oxygen (95-99%) or O 2 -CO 2 -rich environment (Miller, 2017), resulting in a flue gas with very high CO 2 concentration, where the capture of CO 2 is thus normally not needed and CO 2 is basically ready for sequestration (Miller, 2017;Li et al, 2018;Wu et al, 2019). However, in order to obtain nearly pure oxygen (>95%) (Kather et al, 2008), usually a cryogenic air separation unit is required for oxygen separation from air, which makes the whole process costly.…”