SMALL COIL-SHAPED ALL-METAL CATALYST

摘要

1444978 Catalytic unit and element U O P INC 10 Aug 1973 [30 April 1973] 38039/73 Heading B1F A catalyst unit for catalytic treatment, e.g. oxidation, of gaseous materials comprises catalyst retaining means comprising a gas permeable member and defining a region in which to affect contact of gaseous material entering the region via the member with retained catalyst present in the region in the form of a catalyst coating on the surfaces of small coiled high temperature heat resistant alloy wire elements The alloy may be of nickel and chromium; nickel, chromium and iron; or of iron, chromium and aluminium. The metal may be palladium, platinum, ruthenium, thorium, iridium and may be deposited by elctrolysis. The coated coil may have a length and average diameter of 0.25" and the wire may be of 0.05-0.015" diameter. The coils may be helical or flat and may be of circular, oval or rectangular cross section. A catalyst element for use in the unit may be prepared by (a) forming into a small soil heat resistant alloy wire of 0.005"-0.015" diameter, such coil being less than 0.25" in average external diameter and less than 0.25" in length and with coil turn of the resulting coil being spaced from a next adjacent turn by a distance less than the diameter of the wire (b) cleaning the resulting coil with liquid (a) rinsing the elements to remove the liquid (d) electroplating the coil to provide a coating of platinum, palladium or a mixture thereof (e) rinsing the coil and (f) heating the coil in an air steam containing combustible vapours in concentration below the lower limit of explosibility for the mixture and at a temperature providing surface combustion of said vapours thereby affecting a conditioning of the noble metal casting into a porous active state on the alloy wire.