Membrane units can be used as a method to reduce the H2/CO ratio in syngas streams for use in downstream processes. A membrane unit can also be used to produce relatively high purity streams of H2 or CO as well. In a typical membrane unit, the syngas is cooled to remove any condensable hydrocarbons or water, and then heated before entering the membrane. In the membrane, hydrogen preferentially permeates through the membrane, producing a purified hydrogen stream. This results in the remaining stream having a lower, or adjusted, H2/CO ratio.