Abstract: A method for enriching a synthesis gas in hydrogen is presented. The method includes adding H2O to the synthesis gas to form a synthesis gas stream that includes hydrogen, carbon monoxide, and steam. The synthesis gas stream has a steam to dry gas molar ratio, S/DG; and an oxygen to carbon molar ratio, O/C. The method includes introducing the synthesis gas stream into a water-gas shift reactor and reacting the synthesis gas stream in the water-gas shift reactor in the presence of a non-iron-based catalyst to produce a shifted synthesis gas. The method further includes controlling an outlet temperature of the synthesis gas stream to remain at or below a critical temperature or to drop to or below the critical temperature by adjusting the S/DG ratio to maintain the O/C ratio below a lower O/C limit or above an upper O/C limit.