Characteristics of Vanadium-Based Coal Gasification Slag and the NH3-Selective Catalytic Reduction of NO

Fang Han,Yanchun Gao,Weiren Bao,Lina Han,Qihuang Huo,Liping Chang,Jiancheng Wang

doi:10.3390/catal8080327

Fang Han, Yanchun Gao + Show 5 more

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https://doi.org/10.3390/catal8080327

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Abstract

In order to realize the resource utilization of coal gasification slag (CGS) and to effectively control the emission of nitrogen oxides (NOx) in coke oven gas, the effect of the reaction conditions and vanadium loading over the CGS catalysts was carried out for the selective catalytic reduction (SCR) of NO by NH3. The various vanadium loaded CGS catalysts were prepared using impregnation methods. The addition of 1% vanadium to the CGS catalyst (V1/CGS) significantly enhanced the NO conversion at a wide temperature range of 180–290 °C. The catalysts were characterized by N2 adsorption/desorption, X-ray photoelectron spectroscopy, H2-temperature programmed reduction, NH3-temperature programmed desorption, Inductively coupled plasma optical emission spectrometer (ICP-OES), thermo gravimetric analyses (TGA), Fourier Transform infrared spectroscopy (FTIR), Scanning electron microscope-Energy dispersive spectrometer (SEM-EDS), and X-ray powder diffraction (XRD). The experimental results show the following: That (1) the NO removal efficiency of the sample CGS3 was the best, and it could be up to 100% under the experimental conditions; (2) The NO removal efficiency of the catalysts was higher in the atmosphere with SO2 than that without SO2; (3) The XRD results indicated the active component of vanadium was homogeneously dispersed over CGS and the active component of catalyst was V2O5 according to the XPS results. In particular, the NH3-TPD spectra of the vanadium loaded CGS catalyst showed that vanadium produced more acid sites, and the Lewis acid sites on the vanadium species were the active sites for the catalytic reduction of NO at 240–290 °C.

Highlights

IntroductionThe nitrogen oxides emitted from coke oven flue gas pollute our living environment and endanger our physical health
The coking chemical industry is an important part of the coal industry
In the range of 180–260 ◦ C, V1/CGS3 shows a relatively higher DeNOx activity than V1/CGS1 and V1/CGS2, which may be due to the physical properties of V1/CGS3 catalyst

Summary

Introduction

The nitrogen oxides emitted from coke oven flue gas pollute our living environment and endanger our physical health. The coking industry’s flue gas treatment is imminent. NH3 selective catalytic reduction (SCR) technology is the most effective technology for removing NOx from flue gases [1,2]. The commonly adopted commercial catalyst is V2 O5 –WO3 (MoO3 )/TiO2 [2,3,4], and its working temperature must be above 300 ◦ C in order to obtain good catalytic activity and to avoid pore plugging caused by the deposition of ammoniumsulfate salts over the catalyst surface. At low temperatures, the presence of H2 O and SO2 can seriously affect SCR activity [5]. According to the Catalysts 2018, 8, 327; doi:10.3390/catal8080327 www.mdpi.com/journal/catalysts

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