COKE FORMATION AND MINIMIZATION DURING STEAM REFORMING REACTIONS

The formation of coke during the steam reforming of Light hydrocarbons results mainly from catalytic reactions. It is believed that the proc ess is endemic to steam reforming in that the same intermediates are i nvolved in the main reaction as are involved in coking. As a result, c ontrol of coking depends on the control of the kinetics of intermediat e reactions. On an industrial scale, coking can be controlled by contr olling steam/carbon ratios in the feed. It can also be minimised by en semble size control on nickel surfaces and/or by interfering with the reactions leading to carbon. Doping with traces of sulphur or with sma ll amounts of metals that concentrate on the nickel surface is found t o reduce significantly the formation of coke. Further improvements may be possible as a result of detailed studies of support effects in the catalysis.