Hydrogen-Carbon Dioxide Separation by Electrochemcial Pumping

Steam reforming of hydrocarbons or coal followed by the water gas shift reaction produces a mixture of H2, CO2 and H20. The most common approaches to purify the hydrogen are by alkaline scrubbing of the gas mixture to remove the CO2 or pressure swing adsorption. We report here an alternative method of electrochemical pumping of hydrogen from mixtures of H2, CO2 and H20 using a polymer electrolyte membrane. This process produces high purity hydrogen (< 100 ppm CO2) at >98% recovery and modest power requirements. The equipment is essentially a PEM fuel cell run with an applied voltage to pump the hydrogen. Data is presented that shows the efficiency and recovery of this process. Process designs and an energy comparison to both alkaline scrubbing and PSA shows the electrochemical pumping is more energy efficient and readily adaptable for many a wide range of process scales.