Ambient air separation and SOEC front-end for ammonia synthesis gas production

A method for generating ammonia synthesis gas by electrolysis, said method comprising the steps of:

• compressing air and feeding it to an air separation process to form a compressed and refined air, in which the content of nitrogen is concentrated while the content of oxygen and CO2 is diluted;
• feeding a mixture of steam and the compressed and refined air into a first of a series of electrolysis units;
• producing hydrogen by steam electrolysis in the electrolysis units;
• providing nitrogen and steam by burning the hydrogen with the compressed and refined air in or between the electrolysis units, wherein the burning produces a stream including steam and nitrogen which is fed to the next electrolysis unit;
• and
• passing an outlet from one electrolysis unit to an inlet of a next electrolysis unit, either together with compressed and refined air added after each electrolysis unit or only adding compressed and refined air after a last electrolysis unit,
• wherein the electrolysis units are run in thermoneutral or endothermal mode,
• wherein the nitrogen part of the synthesis gas is provided by burning the hydrogen produced by steam electrolysis with the compressed and refined air in the electrolysis units.