A Study on the Regenerable Co and Ni-Based Sorbents to Remove Hydrogen Sulfide at Middle Temperature

Abstract

To remove hydrogen sulfide from hot coal gases at middle temperature, the various sorbents were prepared by precipitation or co-precipitation method. The cobalt and nickel-based sorbents promoted with alumina showed good regeneration properties during multiple cycles. The roles of each component in the sulfidation and regeneration were discussed with the results from XRD and TPD.

Effect of cobalt (nickel) oxide on the properties of zinc–titanium sorbents for high temperature desulphurization of model coal gas

“…For the ZTCo sorbents, conversion of active components did not exceed 45% in any work cycle, while for ZTNi it was in the range 50-70% (Table 3). This observation is convergent with results presented by Park et al (2010). The degree of H 2 S removal on ZTNi increases in subsequent cycles (Fig.…”

“…The XRD patterns of all sulphided sorbents show peaks of mixed metal oxides that indicate incomplete conversion of an active metal oxide to sulphided forms (tests were terminated after reaching 100 ppm H 2 S in the outlet gas). Park et al (2010) and Jun et al (2001) found Co 9 S 8 in the sulphided ZTC sorbent; however, their experiments were performed under different conditions. The X-ray diffraction patterns of the sulphided ZTNi1 and ZTNi2 (Fig.…”

“…In the XRD pattern of sulphided ZTNi3, strong peaks of ZnS (average crystallite size 31.6 nm) and less intense signals of TiO 2 and Ni 3 S 2 are visible. Jun et al (2001) reported that NiS in ZTNi sulphided at medium temperature is amorphous whereas Park et al (2010) found Ni 3 S 4 in sulphided NiO/Al 2 O 3 with high Ni content (50 wt%). It is considered that the phase composition of the sulphided Ni containing sorbents is determined by the sulphidation parameters: temperature, pressure and H 2 S concentration (Wang et al 2016).…”

“…Results of theoretical studies of Girard et al (2014) showed that the concentration of H 2 S under equilibrium conditions with NiO is significantly lower than that in the case of CoO. Park et al (2010) showed that, at medium temperature, the Zn-Ti sorbents doped with Ni are characterised by a higher sorption capacity than those containing of Co.…”

“…Ensuring a stable sorption capacity during sulphidation/regeneration cyclic work is another challenge. Park et al (2010) suggested that the admixture of Ni or Co oxides to Zn-sorbent facilitates regeneration, probably due to a catalytic effect. Girard et al (2015) studied regeneration of Zn-Mo sorbent and found that the oxidation of MoS 2 apparently lowers the temperature of ZnS oxidation.…”