METHOD OF CATALYTICALLY OXIDIZING ALCOHOL VAPOR ACCOMPANIED BY VARYING AMOUNTS OF EXCESS OXYGEN

摘要

21 A method of substantially completely oxidizing alcohol and/or formaldehyde vapor contained in the exhaust gas of a methanol fueled engine, heated to a temperature of about 150.degree.C, while using air/fuel mixtures of lambda from 0.9-7.0 for combustion in the engine, the method comprising the treatment of the exhaust gas mixture (i) by a first catalyst consisting substantially of palladium or palladium and rhodium in a weight ratio of Rh/Pd of 0-0.3 and (ii) subsequently immediately by a second catalyst, physically separate from the first catalyst, and consisting substantially of silver, whereby the oxidation process taking place within the first catalyst promotes more favourable conditions for increased alcohol or formaldehyde oxidation processes within the second catalyst, thereby to produce an oxidized exhaust gas mixture having less than 0.5% of the converted methanol as formaldehyde, and at least 96% conversion of the methanol vapor.