NOVELTY - The process for separating hydrogen and carbon dioxide from a synthesis gas stream, comprises feeding a shifted synthesis gas stream at a pressure of 50 bar gauge to a membrane separator unit that is provided with a membrane having a selectivity for hydrogen over carbon dioxide of greater than 16 for withdrawing a hydrogen enriched permeate stream having a carbon dioxide content of less than 10 mol.% and a carbon dioxide enriched retentate stream comprising 70 mol.% carbon dioxide from the separator unit, and feeding the enriched retentate stream to a carbon dioxide condensation plant.    USE - The process is useful for separating hydrogen and carbon dioxide from a synthesis gas stream, where the carbon dioxide is useful for enhanced oil recovery and a hydrogen stream is useful as fuel for a power plant for generating electricity.    ADVANTAGE - The process is capable of effectively and easily separating hydrogen and carbon dioxide from the synthesis gas stream without nitrogen oxide emissions by reducing the hydrogen partial pressure of the permeate stream using the sweep gas thus improving the separation efficiency.    DETAILED DESCRIPTION - The process for separating hydrogen and carbon dioxide from a synthesis gas stream, comprises: feeding a shifted synthesis gas stream at a pressure of 50 bar gauge to a membrane separator unit that is provided with a membrane having a selectivity for hydrogen over carbon dioxide of greater than 16 for withdrawing a hydrogen enriched permeate stream having a carbon dioxide content of less than 10 mol.% and a carbon dioxide enriched retentate stream comprising 70 mol.% carbon dioxide from the membrane separator unit; feeding the carbon dioxide enriched retentate stream to a carbon dioxide condensation plant, where the retentate stream is cooled to condense out liquid carbon dioxide by: passing the carbon dioxide enriched retentate stream through a first heat exchanger, where the retentate stream is cooled to a temperature below the dew point of the retentate stream but above the triple point of carbon dioxide by heat exchange with a first internal refrigerant stream for forming a two-phase stream comprising a liquid carbon dioxide phase and a vapor phase that is enriched in hydrogen compared with the retentate stream, and the first internal refrigerant stream is a cooled liquid carbon dioxide stream that is produced in the process and is vaporized in the first heat exchanger for forming a first carbon dioxide vapor stream; passing the two-phase stream to a first separator vessel, where the liquid phase is separated from the vapor phase for withdrawing the liquid carbon dioxide stream and the hydrogen enriched vapor stream from first the separator vessel; if the carbon dioxide content of the hydrogen enriched vapor stream is greater than 10 mol.%, passing the vapor stream through a second heat exchanger, where the vapor stream is cooled to a temperature below the dew point of the vapor stream but above the triple point of carbon dioxide by heat exchange with a second internal refrigerant stream for forming an another two-phase stream, where the second internal refrigerant stream is a cooled liquid carbon dioxide stream that is produced in the process and is vaporized in the second heat exchanger for forming a second carbon dioxide vapor stream; and passing the two-phase stream to a second separator vessel, where the liquid phase is separated from the vapor phase for withdrawing the liquid carbon dioxide stream and the hydrogen enriched vapor stream from the second separator vessel, until the carbon dioxide content of the hydrogen enriched vapor stream that is withdrawn from the separator vessel is less than 10 mol.%; passing the hydrogen enriched vapor stream having a carbon dioxide content of less than 10 mol.% and/or the hydrogen enriched permeate stream having a carbon dioxide content of less than 10 mol.% as a fuel feed stream to the combustor of a gas turbine of a power plant at a pressure above the operating pressure of the gas turbines for the production of electricity; compressing the carbon dioxide vapor streams that are formed by vaporization of the internal refrigerant stream for forming a compressed carbon dioxide stream, where the pressure of the compressed carbon dioxide stream is above the critical pressure for carbon dioxide, and the carbon dioxide is either in a supercritical state or a liquid state when the temperature of the compressed carbon dioxide stream is above or below the critical temperature for carbon dioxide respectively; and sequestering the compressed carbon dioxide stream. When the shifted synthesis gas stream is fed to the membrane separation units at 20-40 degrees C, the membrane separation unit is provided with a hydrogen selective membrane that is capable of operating at the temperature of the shifted synthesis gas feed stream. When the shifted synthesis gas stream is fed to the membrane separator unit at 100-300 degrees C, the carbon dioxide enriched retentate stream removed from the membrane separation unit is cooled downstream of the membrane separation unit before the retentate stream enters the carbon dioxide condensation plant. The shifted synthesis gas stream comprises steam, where a condensate comprising water is separated from the cooled carbon dioxide enriched retentate stream before the retentate stream enters the carbon dioxide condensation plant. The shifted synthesis gas stream is cooled to below its dew point for forming a condensate that is separated from the shifted synthesis gas stream. The shifted synthesis gas stream is reheated to 100-300 degrees C. The shifted synthesis gas stream is fed to the membrane separator units at a pressure of 60 barg. The hydrogen enriched retentate stream is withdrawn from the membrane separation units at a pressure that is above the operating pressure of the gas turbines of the power plant. The hydrogen selective membrane that is employed in the membrane separator units has a hydrogen selectivity of greater than 40. The carbon dioxide content of the hydrogen enriched permeate stream is less than 2 mol.%. The carbon dioxide content of the carbon dioxide enriched retentate stream is in 70-85 mol.%. The carbon dioxide enriched retentate stream is passed to a pre-cooling heat exchanger of the carbon dioxide condensation plant, where the retentate stream is pre-cooled to 0-10 degrees C.    DESCRIPTION OF DRAWING(S) - The figure shows a block flow diagram of a separation of a hydrogen enriched fuel stream from a carbon dioxide enriched stream using a hydrogen selective membrane separation unit upstream of a carbon dioxide condensation plant.