Start-up with ruthenium catalysts

This patent describes a process for the conversion of synthesis gas to hydrocarbons by contacting at reaction conditions a feed characterized as an admixture of carbon monoxide and hydrogen with a bed of particulate ruthenium catalyst constituted of a catalytically active amount of ruthenium composited with titania, or a titania-containing support. The improvement is described comprising contacting and pretreating the catalyst, prior to initiating the conversion reaction, with an admixture of steam and a carrier gas or an admixture of steam and hydrogen at temperatures ranging from about 2000C. to about 5500C. It is sufficient to mildly agglomerate and ruthenium and form on the particles of catalyst larger agglomerates of ruthenium of average crystallite size from about 15 A to about 25 A approximating that obtained on completion of the startup portion of a synthesis gas operating run