Hallgeir Klette

Chapter 21 – Grace: Development of Supported Palladium Alloy Membranes

The Grangemouth Advanced CO 2 Capture Project (GRACE) was a two-year (2002–2003) research program concerned with the capture of CO 2 from a UK refinery site. One of the technologies that were pursued in the program was the development of hydrogen gas separation by membrane technology. Such technology can be used to enhance the water gas shift reaction for CO 2 capture by pre-combustion decarbonization of refinery fuel gas. This chapter presents the development and testing of flat and tubular supported palladium alloy membrane modules. Membranes with thickness in the range of 1 μm are prepared by a two-stage magnetron sputter process using a single crystal silicon wafer as intermediate support and a wire mesh or porous material as final support. Testing of the hydrogen flux through the tubular membranes at 300 °C has shown that permeance values of about 3 × 10 −6 mol/(m 2 s Pa) can be attained. For a flat membrane, peak permeance values of about 6.8 × 10 −6 mol/(m 2 s Pa) is attained at 300 °C. The membranes are able to separate hydrogen gas from nitrogen gas with 100% selectivity within the detection limits of the equipment. Tubular membrane supports that have been reinforced by a steel insert are tested up to 14 bar transmembrane pressure. Although the selectivity drops at high pressure, the tests show that the membrane film does not disintegrate at high pressure even at 300 °C.