Testing of novel sorbents for H₂S removal from coal gas

Abstract

Application of zinc ferrite, a regeneruble mixed metal oxide, for the removal of H2S from hot coal derived gas streams is limited to a maximum temperature of about 1,250"F (677°C) and to a minimum H2S concentration of about 5 ppmv in the cleaned gas. Four novel sorbents that have shown potential for ocercoming the limitations of zinc ferrite [ l , 41 were selected for development and bench-scale testing. Several variations of these mixed metal oxides were prepared, using different amounts of binders. They were tested in the presence of simulated coal gas using a thermogravimetric reactor (TGR) for selection of preparations possessing an adequate combination of reactivity, regenerability, capacity, and strength. Limited bench-scale tests were conducted in the presence of simulated fluidized-bed coal gas$er product gases at pressures from 1 to 2 MPa, temperatures from 525°C to 625°C and space velocities from 1,000 to 3000 Nm3/(m3 * h).

Advanced Sorbent Development Program; Development of Sorbents for Moving-Bed and Fluidized-Bed Applications

“…58 Because of the apparent limitations of the zinc ferrite sorbent, many investigators have been conducting research to develop a superior mixed metal oxide sorbent. [42][43][44][45][59][60][61][62][63] Earlier experimental studies that pioneered the use of mixed-metal oxides were performed at the Massachusetts Institute of Technology (MIT), [64][65][66] Research Triangle Institute (RTI), 67 68 Electrochem, 69 44,45 has shown that titanium oxide is a better alternative to iron oxide additives in terms of the higher stability of the titanates over the ferrite compounds of zinc, and their similar sulfidation equilibria. With zinc titanates, the sulfidation temperature has been shown to extend to 700 °C, and sintering of the ZnO was greatly reduced.…”

Effect of Preparation on Structure and Magnetic Properties of ZnFe2O4

“…Recently, progress in synthesis techniques has initiated new surge of concern in ferrites to improve their physical properties and develop their applications [1][2][3]. Zinc ferrite has long attracted researcher's interests because of its intriguing magnetic properties compared with other spinel ferrites.…”

Application of IGCC Technology to Power Generation

“…Not surprisingly, only a few metal oxides can meet all these stringent requirements simultaneously. Iron oxide [21], zinc oxide [22], copper oxide, as well as mixed-metal oxide compounds such as zinc titanates [23,24] and other copper-based [25) compounds have been investigated for use as regenerable sorbents in HGCU applications.…”