Mercury emissions and removal by ash in coal-fired oxy-fuel combustion

Spörl, Reinhold; Belo, Lawrence; Shah, Kalpit; Stanger, Rohan; Giniyatullin, Roman; Maier, Jörg; Wall, Terry; Scheffknecht, Günter

Title: Mercury emissions and removal by ash in coal-fired oxy-fuel combustion
Creator: Spörl, Reinhold; Belo, Lawrence; Shah, Kalpit; Stanger, Rohan; Giniyatullin, Roman; Maier, Jörg; Wall, Terry; Scheffknecht, Günter
Relation: Xstrata Coal Low Emissions R&D Corporation Pty Ltd..CC08-71
Relation: Energy & Fuels Vol. 28, Issue 1, p. 123-135
Publisher Link: http://dx.doi.org/10.1021/ef4014604
Publisher: American Chemical Society
Resource Type: journal article
Date: 2014
Description: This paper presents results of experiments performed at a 20 kW once-through combustion rig of the Institute of Combustion and Power Plant Technology (IFK) of the University of Stuttgart. A methodology to investigate oxy-fuel process configurations was used in which impurities were injected to the oxidant gas of the once-through reactor to simulate different extents of oxy-fuel recycle gas treatment. Three Australian coals, which had previously been tested in the Aioi furnace of IHI in Japan, were used in the experiments. A comprehensive set of total (Hg^tot), elemental (Hg⁰), and oxidized (Hg²⁺) mercury concentrations was measured for various air and oxy-fuel combustion conditions. These data enable an evaluation of process parameters that influence the Hg emissions of an oxy-fuel combustion process. A theoretical mass balance between Hg fed to the process (fuel and Hg⁰ injection) and Hg measured before the filter matched well, indicating that no mercury was captured by fly ash at high temperatures. The capture of Hg⁰ and oxidized Hg²⁺ by ash in a baghouse filter has been determined for all experiments. Measured Hg concentrations show an increase when switching from air to oxy-fuel operation for all investigated coals and oxy-fuel settings, even when no additional Hg⁰ is injected to the oxidant gas. Moreover, the Hg²⁺/Hg^tot ratios in the flue gas are higher during oxy-fuel combustion. The Hg capture by ash in the baghouse filter has been found to reduce the Hg emissions considerably. Reduction rates in a range between 18 and 51% for air and between 11 and 29% for oxy-fuel combustion were observed.
Subject: oxy-fuel combustion; Australian coals; gas treatments
Identifier: http://hdl.handle.net/1959.13/1302484
Identifier: uon:20478
Identifier: ISSN:0887-0624
Language: eng
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