Systems and methods for pressurizing hydrogen used in proton exchange membrane fuel cells

A fuel cell system, the system comprising:

• a proton exchange membrane (PEM) fuel cell configured to receive hydrogen and air to produce electrical power for an electrical load;
• a hydrogen production unit for producing the hydrogen, the hydrogen production unit comprising:
• a reformer for reforming a hydrocarbon to produce an output stream comprising the hydrogen and a plurality of secondary outputs;
• a separator for separating the output stream into a raffinate stream at a first pressure and at least a portion of the hydrogen at a second pressure, wherein the second pressure is lower than the first pressure;
• and
• a turbocharger comprising:
• a turbine expander for receiving the raffinate stream at the first pressure and exhausting the raffinate stream at a third pressure, wherein the third pressure is lower than the first pressure, wherein an expansion of the raffinate stream rotates a shaft rotationally connected to the turbine expander;
• and
• a compressor for receiving the portion of the hydrogen at the second pressure and compressing the portion of the hydrogen to a fourth pressure, wherein compressor is rotationally connected to the shaft.

A method of operating a fuel cell system, the method comprising:

• reforming a hydrocarbon to produce a reformer output comprising hydrogen and a plurality of secondary outputs;
• separating the reformer output into a hydrogen stream at a first pressure and a raffinate stream at a second pressure;
• directing the hydrogen stream into a compressor of a turbocharger to compress the hydrogen stream from the first pressure to a third pressure, wherein the third pressure is higher than the first pressure;
• and
• directing the raffinate stream into a turbine expander of the turbocharger, wherein an expansion of the raffinate stream in the turbine expander powers the compressor to compress the hydrogen stream from the first pressure to a third pressure.