Process for the production of synthesis gas by catalytic steam reforming
of a hydrocarbon containing feedstock in parallel in an autothermal steam
reformer and in one or more steam reformers in series, the heat for the
steam reforming reactions in the one or more steam reformers being
provided by indirect heat exchange with the combined effluents from the
one or more steam reformers with the autothermal steam reformer, and
wherein carbon monoxide containing gas is added to the feedstock prior to
the steam reforming in the autothermal steam reformer and/or prior to the
steam reforming in the one or more steam reformers, the carbon monoxide
containing gas having a molar ratio of hydrogen to carbon of less than
4.5 and being added in an amount resulting in a product stream having a
molar ratio of hydrogen to carbon monoxide of between about 1.8 and 2.3.