improved media for positive and rigid catalysts of purification of exhaust gases of diesel engines

摘要

1406903 Catalyst support element and method of preparing such an element SOC GENERALE DES PRODUITS REFRACTAIRES 2 Feb 1973 [4 Feb 1972] 5362/73 Heading B1F A catalyst support element for a catalyzer apparatus for purification of motor exhaust gases comprises a porous rigid unitary element composed of interwoven ceramic fibres and refractory binding material, the bonded fibre composition having an apparent density of not more than 0.6, an open porosity of at least 70%, a compressive strength of at least 100% by weight, a shrinkage when heated from ambient temperature to 1,000‹C of not more than 2%, and a specific surface area of at least 10 mSP2/SP/g, and shows substantially no deterioration after at least 100 thermal shocks, where a thermal shock is the effect occurring on the catalyst support of the sudden introduction thereof into an enclosure at 800‹C, maintaining it therein for 15 minutes, and thereafter cooling the catalyst support element in air at ambient temperature. A method of making the element comprises forming a paste of refractory ceramic fibres and a refractory binder material, introducing the paste into a mould, drying the formed shape and thereafter firing the shape at a temperature of from 1200-1300‹C, impregnating the resulting product with a gel or mol of at least one refractory oxide or a mixture of at least one refractory oxide with metals that form refractory oxides, drying the impregnated product and then firing the dried product at a temperature of 600-800‹C.