Desulfurization Performance and Kinetics of Potassium Hydroxide-Impregnated Char Sorbents for SO₂ Removal from Simulated Flue Gas

Abstract

Potassium hydroxide-impregnated char sorbents (KOH/char) prepared via an ultrasonic-assisted method were used for SO 2 removal from flue gas. The desulfurization experiment was analyzed using a fixed-bed reactor under 40–150 °C temperature range, using simulated flue gas. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy, and scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM/EDS) were used to analyze both the chemical and physical characteristics of the sorbents. The analyzed results exposed that the complete elimination of SO 2 from flue gas was achieved when using the char/KOH sorbent with a mass ratio of char to KOH of 11:1. It was noted that temperature had a substantial influence on the desulfurization performance with sulfur capacity maximized at 100 °C. Experimental results also revealed that a small amount of O 2 present in the solvent could improve the SO 2 removal efficiency of the sorbent. The analyzed XRD patterns showed that K 2 SO 4 was the main desulfurization product, which was consistent with the SEM/EDS analysis. The experimental results were well-described with the Lagergren first-order adsorption kinetics model with the activation energy ( E a ) of the SO 2 adsorption by KOH/char sorbent of 20.25 kJ/mol.

Impregnated Activated Carbon Materials for Respiratory Purpose. Chemisorption of Sulfur Dioxide

“…Functional groups have a great influence on SO 2 adsorption and oxidation [40,48,49]. Currently, the experimental study of this effect was carried out by impregnating AC or raw materials for its production with aqueous solutions of HNO 3 [27,29,[50][51][52][53], H 3 PO 4 [53,54], KOH [29,33,[54][55][56][57], NaOH [39, 51, 58]); modification or activation by high-temperature gas or steam: CO 2 [33, 54], H 2 O [33], etc.…”

“…Microporous AC obtained by mixing anthracite with KOH or NaOH was distinguished by a large surface area, which makes it a promising sorbent for SO 2 capture [55]. In addition, the products of desulfurization are alkali metal sulfates (K 2 SO 4 , Na 2 SO 4 , etc.)…”

Role of Surface Paramagnetic Oxygen Species in the Desulfurization Reactions on Zinc Oxide

“…However, the tail gas of the Claus process (the Claus tail gas) still contains ∼0.1% H 2 S and therefore requires further removal (or deep desulfurization). Desulfurization of the SO 2 gas is performed by the wet flue gas desulfurization process, in which it is oxidized to SO 3 on a range of surfaces, such as carbonaceous materials. , The development of new materials and technologies for the removal of both H 2 S and SO 2 is a highly intense research activity because the current approaches are still suffering from various drawbacks. These include the H 2 S desulfurization reaction causing chemical changes to the sorbent material and therefore affecting the recyclability of the surface and the wet flue gas desulfurization process for the removal of SO 2 causing high water consumption and high costs …”

“…These include the H 2 S desulfurization reaction causing chemical changes to the sorbent material and therefore affecting the recyclability of the surface 6 and the wet flue gas desulfurization process for the removal of SO 2 causing high water consumption and high costs. 5 ZnO has been intensively investigated as a candidate surface for the removal of H 2 S 2,6−14 but not as much for the removal of SO 2 . 15 The reaction process investigated for ZnO for the removal of H 2 S is the two-step Claus process.…”