Surface characterization of Pd/Al₂O₃sorbents for mercury capture from fuel gas

Abstract

The surface composition of a series of Pd/alumina sorbents has been characterized to better understand the factors influencing their ability to adsorb mercury from fuel gas. Both a temperature effect and a dispersion effect were found. Maximum adsorption of Hg occurred at the -lowest temperature tested, 204°C, and decreased with increasing temperatures. Maximum adsorption of Hg on a per-atom basis of Pd is observed at low loadings of Pd ( < S.5% Pd) due to better dispersion of Pd at those loadings; a change in its partitioning occurs at higher loadings. The presence of H2S "in the fuel gas acts to promote the adsorption of Hg through its association with Hg in the Pd lattice.

Elemental Mercury Capture from Syngas by Novel High-Temperature Sorbent Based on Pd–Ce Binary Metal Oxides

“…PC x A sorbents with higher CeO 2 loadings showed stronger sulfur-tolerance performance until the CeO 2 /Al 2 O 3 mass ratio reached 1.0, with E cap being greater than 30% at 270 °C. PC1.0A showed the highest Hg 0 removal efficiency, which was likely due to an excellent sulfur removal performance resulting from a relatively higher surface area . Further increasing the CeO 2 /Al 2 O 3 mass ratio to 1.5 also resulted in a slight decrease of E cap .…”

EXAFS and XRD characterization of palladium sorbents for high temperature mercury capture from fuel gas

“…It has been shown that palladium offers an attractive option for mercury vapour removal from fuel gas at elevated temperatures, though it would probably require sorbent regeneration to make it cost competitive. [9][10][11][12][13][14] We have also previously reported the Hg adsorption capacities of a range of Pt/alumina and Pd/alumina sorbents using a synthetic fuel gas feed containing Hg vapour at temperatures from 204 to 388 1C. 15,16 Here we focus our attention on the use of supported Pd sorbent materials, in particular silica and alumina supported systems.…”

“…Although supported metal catalysts, in particular palladium-based systems, are extensively used in the field of catalysis, [17][18][19][20][21][22] only a few examples are reported in the literature for their use in scavenging mercury. [9][10][11][12] Most previous studies have focused on the use of chemical characterization methods to estimate and understand the mercury uptake. Although such studies provided direct evidence for the removal of mercury from the fuel gas, the nature of adsorbed mercury in the sorbent material is poorly understood.…”

High-Performance Arsine Removal Using CuOx/TiO2 Sorbents under Low-Temperature Conditions

“…Additionally, copper oxide possessed the advantages of easy preparation, low toxicity, and low cost. Palladium (Pd) is an excellent sorbent for the removal of AsH 3 , Hg, and H 2 Se from fuel gas at elevated temperatures − and has attracted significant research attention recently. However, palladium is not yet widely employed for arsine capture due to the small number of gasification facilities in the United States, as well as the need for further demonstration of the technology.…”