Metallic Filters for Hot Gas Cleaning

Abstract:

<p>This document is the final report for the project titled 'Metallic Filters for Hot Gas Cleaning'.</p> <p>Hot gas filtration has not only been adopted as an essential system component in hybrid technologies like the Air Blown Gasification Cycle, but is also being used to remove particulate prior to water scrubbing of fuel gases in first generation Integrated Gasification Combined Cycle (IGCC) plants. The unreliability of the ceramic filter elements in demonstration trials and the high capital cost of these particle removal systems have hindered their application and are factors restricting the uptake of gasification power plants in general. The successful development of a durable metallic filter system for the Air Blown Gasification Cycle (ABGC) would be a major step towards its implementation. Metallic filter elements have potential applications in all IGCC systems and in other industries requiring hot gas cleaning.</p> <p>This project aimed to identify the optimum materials for the various component parts of metallic filter elements, evaluate candidate fabrication routes and determine likely service lives in gasifier hot gas path environments typical of IGCC and ABGC.</p> <p>A screening test (Activity A) was carried out to aid the selection of candidate materials for exposure in the main materials test programme (Activity B). The materials chosen for inclusion in the second phase tests were: Haynes D205 EN2691, Fecralloy, Haynes HR160, IN690, Haynes 188, AISI 310, IN C276, Hastelloy X, IN Alloy 800HT, AISI 316L and Iron Aluminide. Activity B tests were carried out in two environments, simulating high sulphur content IGCC fuel gas and low sulphur content ABGC fuel gas. The materials were evaluated at temperatures of 450, 500 and 550&deg;C for the high sulphur gas and at 550&deg;C for the low sulphur gas, for periods up to 3000 hours.</p> <p>Using the results of Activity B, existing corrosion life prediction models for gasification environments developed at Cranfield University, have been modified and used to predict the expected service lives under operational IGCC/ABGC filter conditions (Activity C). The design requirements for a prototype element for IGCC/ABGC applications have been identified and related to the data produced in this project (Activity D).</p> <p>When compared to the ABGC gas environment, the IGCC gas environment has been shown to cause significantly greater damage. The damaging effect of deposit coatings has also been demonstrated. The materials tested in Activity B have been ranked in order of degree of oxidation and Haynes D205 EN 2691, Fecralloy and HR 160 have shown the best performance.</p> <p>The project has provided the basis for new opportunities for the development of metallic filter media in gasification environments. To confirm this potential the manufacture of full sized elements is required together with their demonstration in pilot scale trials and in commercial installations. In addition to coal, biomass gasification can benefit from the improved reliability and filtration performance offered by metallic filters and it is recommended that further work is undertaken to evaluate materials suitable for operating in such environments.</p> This report is divided into the following sections: <ol> <li>Introduction</li> <li>Overall Aim</li> <li>Background</li> <li>Experimental</li> <li>Summary</li> <li>Recommendations</li> <li>Acknowledgements</li> <li>References</li> </ol>

Author(s):

Kilgallon, P., Simms, N.J., Oakey, J.E. & Boxall, I.