• Login
    View Item 
    •   NWU-IR Home
    • Research Output
    • Faculty of Engineering
    • View Item
    •   NWU-IR Home
    • Research Output
    • Faculty of Engineering
    • View Item
    JavaScript is disabled for your browser. Some features of this site may not work without it.

    Trace element behaviour in the Sasol-Lurgi MK IV FBDB gasifier. Part 1. The volatile elements: Hg, As, Se, Cd and Pb

    Thumbnail
    Date
    2008
    Author
    Bunt, J.R.
    Waanders, F.B.
    Metadata
    Show full item record
    Abstract
    Coal-fired power and heat production are the largest single source of Hg in the atmosphere, and in March 2005, the US-EPA ruled regarding Hg reduction from coal utilization in the USA. Appropriate Hg pollution control of technology, as well as reductions in the uses of Hg and coal-containing Hg can readily reduce the releases of Hg from coal utilities. Integrated multi-pollutant (SOx, NOx, particulate matter and Hg) control technologies may be a cost-effective approach. Prior to considering mitigation technologies, it is necessary to understand the quantity of mercury in the feed coal, its mode of occurrence (i.e. mineral or organic associations), its partitioning behaviour during the process, and the volume and species in which it is being emitted via stacks. These factors have all been investigated up to the point of release for the Sasol gasification and steam-raising plants, including other trace elements. The focus of this paper is to discuss the more recent environmental research developments by Sasol, where trace element simulation and validation of model predictions have been undertaken for the Sasol–Lurgi gasification process operating on lump coal. Fact-Sage thermodynamic equilibrium modeling was used to simulate the trace elements: Hg, As, Se, Cd and Pb gas phase and ash phase partitioning and speciation behaviour occurring in a fixed-bed pressurised gasifier. A Sasol–Lurgi Mark IV (MK IV) fixed-bed dry bottom (FBDB) gasifier was mined via turn-out sampling in order to determine the trace element changes through the gasifier, findings being used to validate the modeled results. This paper will focus on the behaviour of the volatile Class I trace elements: Hg, As, Se, Cd and Pb within the Sasol–Lurgi MK IV FBDB gasifier as function of coal quality. This study excludes the downstream gas cleaning partitioning and speciation behaviour of these elements, which will form the basis of a future paper. Good agreement between model-predictions and measurements have been attained in this study, with the exception of As. Hg, Cd, Pb, As and Se were all found to be highly volatile, partitioning into the gas phase. Hg was found to be the most volatile element during fixed-bed gasification and is present in the gas phase in the form of elemental Hg (g). As, Se, Cd and Pb have lower volatilities when compared to Hg, and they vary in an order: Hg > Se > Cd > Pb > As. Speciation predictions showed that: Hg, AsH3, H2Se, PbSe, Cd, CdS, and PbS/Pb/PbCl, species could potentially exist in the raw gas phase
    URI
    http://hdl.handle.net/10394/5893
    https://www.sciencedirect.com/science/article/abs/pii/S001623610800032X
    https://doi.org/10.1016/j.fuel.2008.01.017
    Collections
    • Faculty of Engineering [1107]

    Copyright © North-West University
    Contact Us | Send Feedback
    Theme by 
    Atmire NV
     

     

    Browse

    All of NWU-IR Communities & CollectionsBy Issue DateAuthorsTitlesSubjectsAdvisorThis CollectionBy Issue DateAuthorsTitlesSubjectsAdvisor

    My Account

    LoginRegister

    Copyright © North-West University
    Contact Us | Send Feedback
    Theme by 
    Atmire NV