Development and Evaluation of Nanoscale Sorbents for Mercury Capture from Warm Fuel Gas

Jadhav, Raja A. ; Meyer, Howard

Gas Technology Institute

关键词: Desorption;    Testing;    Capacity;    X-Ray Diffraction;    01 Coal, Lignite, And Peat;   

DOI  :  10.2172/881997
RP-ID  :  none
RP-ID  :  FC26-04NT42312
RP-ID  :  881997

美国|英语

来源: UNT Digital Library

【 摘 要 】

Gas Technology Institute (GTI), in collaboration with Nanoscale Materials, Inc. (NanoScale), is developing and evaluating several nanocrystalline sorbents for capture of mercury from coal gasifier (such as IGCC) warm fuel gas. The focus of this study is on the understanding of fundamental mechanism of interaction between mercury and nanocrystalline sorbents over a range of fuel gas conditions. Detailed chemical and structural analysis of the sorbents will be carried out using an array of techniques, such as XPS, SEM, XRD, N{sub 2}-adsorption, to understand the mechanism of interaction between the sorbent and mercury. The proposed nanoscale oxides have significantly higher reactivities as compared to their bulk counterparts, which is a result of high surface area, pore volume, and nanocrystalline structure. These metal oxides/sulfides will be evaluated for their mercury-sorption potential in an experimental setup equipped with state-of-the-art analyzers. Initial screening tests will be carried out in N{sub 2} atmosphere, and two selected sorbents will be evaluated in simulated fuel gas containing H{sub 2}, H{sub 2}S, Hg and other gases. The focus will be on development of sorbents suitable for higher temperature (420-640 K) applications. As part of this Task, several metal oxide (MeO)-based sorbents were evaluated for capture of mercury (Hg) in simulated fuel gas (SFG) atmosphere at temperatures in the range 423-533 K. Nanocrystalline sorbents prepared by NanoScale Materials, Inc. (NanoScale) as well as in-house (GTI) sorbents were evaluated. These supported sorbents were found to be effective in capturing Hg at 423 and 473 K. Based on the desorption studies, physical adsorption was found to be the dominant capture mechanism with lower temperatures favoring capture of Hg. A nanocrystalline sorbent formulation captured 100% of Hg at 423 K with a 4-hr Hg-sorption capacity of 2 mg/g (0.2 wt%) in SFG. The high capacity of the nanocrystalline sorbent is believed to be the result of its high surface area and small crystallite size.