Steam reforming of sugars: Roles of hydroxyl group and carbonyl group in coke formation

Abstract

Steam reforming of sugars features with the high tendency towards coke formation, which relates to the multiple hydroxyl groups and the carbonyl functionality. In this study, steam reforming of glucose, fructose and sorbitol were conducted to clarify the roles of these functionalities in the formation of coke. The results showed that reforming of sorbitol produced more hydrogen and less coke, unlike those of glucose and fructose which produced rather little hydrogen and too much coke. The carbonyl functionality was the main reason for the serious coking behavior but not the multiple hydroxyl groups. The coke from the reaction of sorbitol was mainly catalytic coke with a higher C/H and more defective large fused aromatic rings, which was more thermally stable, more resistant towards oxidation and having a higher crystallinity. Unlike those produced by the reforming of glucose and fructose. Functionalities of the sugars determined the properties of the coke generated.