Maximizing steam methane reformer combustion efficiency by pre-heating pre-reformed fuel gas

A method for improving thermodynamic efficiency in a hydrogen generation system, the method comprising the steps of:

• a) desulfurizing a hydrocarbon to form a process gas stream and a fuel gas stream in a hydrodesulfurization (HDS) unit;
• b) pre-reforming the process gas stream in a first pre-reformer at a first pressure in the presence of steam under conditions effective to form a pre-reformed process gas stream;
• c) pre-reforming the fuel gas stream in a second pre-reformer at a second pressure in the presence of steam under conditions effective to form a pre-reformed fuel gas stream, wherein the first pressure is larger than the second pressure;
• d) drying the pre-reformed fuel gas stream by cooling the fuel gas stream to a temperature below the dew point of water thereby producing a dry fuel gas stream;
• e) heating the dry fuel gas stream to form a heated dry fuel gas stream;
• and
• f) converting methane within the process gas stream into carbon monoxide and hydrogen, thereby producing a syngas stream in a reaction zone of a reformer and a flue gas stream in a combustion zone of the reformer through combusting the heated dry fuel gas stream in the combustion zone of the reformer in the presence of combustion oxidant, wherein the combustion chamber is configured to exchange heat with the reaction zone;
• and
• g) introducing the syngas stream into a pressure swing adsorption (PSA) unit under conditions effective for producing a product hydrogen stream and a PSA off-gas stream.