Abstract: A gas turbine system includes a fuel reformer comprising: a fuel inlet; an oxygen inlet; a pre-mixing zone configured to mix the fuel and the oxygen in a pre-mixing device to form a gaseous pre-mix; wherein the pre-mixing device comprises a flow conditioning device configured to pre-condition the fuel stream, wherein the flow conditioning device is disposed upstream of the oxygen inlet; a diffuser disposed downstream of the flow conditioning device; a catalytic partial oxidation zone disposed downstream of the diffuser, wherein the catalytic partial oxidation zone comprises a catalyst composition configured to react the fuel and the oxygen to generate a syngas. The generated syngas is then mixed with rest of the fuel to form a hydrogen-enriched fuel mixture, which is then sent to the combustion chamber of a gas turbine to reduce the NOx emission and extend the lean blow out limit.