Stabilisation of pyrophoric copper-zinc oxide catalyst - by heating in non-oxidising gas with gradual addition of oxygen

摘要

Stabilisation of pyrophoric Cu-ZnO catalysts is carried out by heating in a non-oxidising gas stream, then adding O2 to an initial concn. of 0.2-0.5 vol % rising in stages by 25-100% to 1 vol % without exceeding the heating temp. until 93% of the Cu is still in the elementary form, as in DT 2015585, in which the temp. used is 38-66 degrees C. The improvement comprises heating to 66-107 degrees C and maintaining at 60-107 degrees C at an O2 concn. of 0.2-0.5 vol % which is increased first by 20-100% and then in stages by 25-100%, whilst the temp. is kept at max. 107 degrees C, then last heating stage being continued until the oxidn. reaction ceases. The use of a higher temp. reduces the treatment time without impairing the activity of the catalyst and it is not necessary to add water vapour to the oxiding gas.