NOVELTY - Capturing and isolating carbon dioxide and hydrogen gases from a high temperature synthesis gas stream containing carbon monoxide and sulfur compounds, comprises: reducing temperature of high temperature synthesis gas stream; removing all sulfur compounds in synthesis gas stream; converting a first portion of carbon monoxide present in the synthesis gas stream to carbon dioxide using a first high temperature water-gas shift reaction; converting a second portion of carbon monoxide to carbon dioxide; converting a third portion of carbon monoxide to carbon dioxide; and separating all hydrogen.    USE - The method is useful for capturing and isolating carbon dioxide and hydrogen gases from a high temperature synthesis gas stream (claimed).    ADVANTAGE - The method: allows removal of the unwanted sulfur contaminants; and produces more fuel efficient feed to a gas turbine engine.    DETAILED DESCRIPTION - Capturing and isolating carbon dioxide and hydrogen gases from a high temperature synthesis gas stream containing carbon monoxide and sulfur compounds, comprises: reducing the temperature of the high temperature synthesis gas stream; removing all the sulfur compounds present in the synthesis gas stream; converting a first portion of carbon monoxide present in the synthesis gas stream to carbon dioxide using a first high temperature water-gas shift reaction; converting a second portion of carbon monoxide present in the synthesis gas stream to carbon dioxide using a second low temperature water-gas shift reaction; converting a third portion of carbon monoxide present in the synthesis gas stream to carbon dioxide using a third low temperature water-gas shift reaction; and separating out all hydrogen present in the synthesis gas stream after completing the first, second and third water-gas shift reactions. An INDEPENDENT CLAIM is also included for system for generating electrical power using a modified synthesis feed, comprising: a gasification device for generating a synthesis gas feed comprising free hydrogen, steam, carbon monoxide, methane, carbon dioxide, nitrogen and sulfur compounds, a high temperature desulfurization unit configured to remove the sulfur compounds from the synthesis gas feed, a first high temperature water-gas shift reactor configured to convert carbon monoxide in the synthesis gas feed to carbon dioxide and form a first converted synthesis gas stream, a second low temperature water-gas shift reactor configured to further convert carbon monoxide to carbon dioxide to form a second converted synthesis gas stream, a third low temperature water-gas shift reactor configured to further convert carbon monoxide to carbon dioxide to form a third converted synthesis gas stream, a hydrogen separator comprising membranes configured to separate out free hydrogen from the third converted synthesis gas stream, a gas turbine engine configured to receive and combust the free hydrogen, and an electrical generator coupled to the gas turbine engine.    DESCRIPTION OF DRAWING(S) - The figure shows a process steps and components of the system for capturing and isolating carbon dioxide and hydrogen gases from a high temperature synthesis gas stream (Drawing includes non-English language text).    High temperature desulfurization feed line (12)    High temperature desulfurization unit (13)    High temperature shift feed (14)    High temperature shift exhaust feed (16)    Discharge (18)