Effects of H2O and CO2 on the catalytic oxidation property of V/W/Ti catalysts for SO3 generation. (1st February 2019)

• Record Type: Journal Article
• Authors: Qing, Mengxia; Su, Sheng; Wang, Lele; Liu, Lijun; Sun, Zhijun; Mostafa, Mohamed E.; Xu, Kai; Hu, Song; Wang, Yi; Xiang, Jun
• Is Part Of: Fuel. Volume 237(2019)
• Page Start: 545
• Page End: 554
• Publication Date: 2019-02-01
• Subjects: SCR catalyst -- SO2 oxidation -- SO3 generation -- H2O and CO2; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2018.09.152
• Languages: English
• ISSNs: 0016-2361

Abstract

Graphical abstract: Highlights: H2 O and CO2 have a nonlinear effect on the generation of SO3 . High concentration of H2 O decreases SO3 generation by inhibiting SO2 adsorption. High concentration of CO2 decreases of SO3 generation by decreasing Oα proportion on catalyst. Abstract: The understanding of the generation mechanism of SO3 on V/W/Ti catalysts provides needed information for the achievement of ultra-low emission of pollutants and effective control of SO3 generation. This study predominantly investigates the catalytic oxidation mechanism of V/W/Ti catalysts for SO3 generation under H2 O and CO2 conditions. Ion Chromatography (IC), X-ray Fluorescence (XRF), Brunauer–Emmett–Teller (BET) specific surface area, Scanning Electron Microscopy image (SEM), Energy Dispersive X-ray (EDX), SO2 Temperature-Programmed Desorption (SO2 -TPD), X-ray Photoelectron Spectroscopy (XPS) experiments, and Fourier Transform Infrared spectroscopy (FT-IR) were used to characterize catalyst properties and the catalytic oxidation generation mechanism of SO3 . Results show that Catalyst V content was more influential than physical property on the generation of SO3 . In this study, when H2 O or CO2 was added into the reaction atmosphere, the generation amount of SO3 would increase firstly, and then gradually decrease with the further increase of H2 O or CO2 concentration. Through further mechanistic analysis, it was found that the influence mechanism of H2 O and CO2 on the generation of SO3 was different. Various kinds of intermediate species such as [OH] and HOSO2 were introduced by the addition of H2 O, resulting in the increase of lattice oxygen (Oα) proportion and SO3 generation path. However, the inhibition effects of high concentration of H2 O on SO2 adsorption and sulfur oxides migration were the main reason for the decrease of SO3 generation under high H2 O containing conditions. Conversely, although the adsorption SO2 was promoted by CO2, high CO2 addition leads to the apparently reduction of Oα proportion on catalyst resulting in the decrease of SO3 generation.