A method for operating a steam reforming plant wherein a hydrocarbon-rich feed is reacted with steam to form synthesis gas. The plant includes a steam reforming reactor and processing units to obtain a hydrogen-rich fraction after separation of carbon dioxide and carbon monoxide. The plant also includes a pressure-swing adsorption plant to separate the hydrogen-rich fraction into product and residual gas. A recycle compressor is included and allows the plant to operate is two different modes. In the first mode, carbon dioxide separated from the synthesis gas is compressed and added to the hydrocarbon-rich feed. In the second mode, the recycle compressor is used to recycle residual gas from the pressure-swing adsorption plant to the hydrogen-rich fraction upstream of the pressure-swing adsorption plant.