Alkaline electrolysis arrangement with deaerator and method therefor

A method for producing hydrogen and oxygen by electrolysis of an alkaline electrolysis medium, in which the hydrogen so produced comprises an Argon content of less than 50 ppb (v/v), the method comprising the method steps of

• electrochemical splitting of water contained in the alkaline electrolysis medium by means of an electrolysis cell stack, whereby a hydrogen loaded catholyte withdrawn from a cathode section of the electrolysis cell stack and an oxygen loaded anolyte withdrawn from an anode section of the electrolysis cell stack are obtained;
• supplying the hydrogen loaded catholyte to a catholyte gas-liquid separator to separate hydrogen from the hydrogen loaded catholyte, whereby hydrogen gas and a hydrogen depleted catholyte are obtained;
• supplying the oxygen loaded anolyte to an anolyte gas-liquid separator to separate oxygen from the oxygen loaded anolyte, whereby oxygen gas and an oxygen depleted anolyte are obtained;
• withdrawing the hydrogen depleted catholyte from the catholyte gas-liquid separator, cooling the hydrogen depleted catholyte and supplying the hydrogen depleted catholyte to the cathode section of the electrolysis cell stack;
• withdrawing the oxygen depleted anolyte from the anolyte gas-liquid separator, cooling the oxygen depleted anolyte and supplying the oxygen depleted anolyte to the anode section of the electrolysis cell stack;
• degassing the hydrogen depleted catholyte withdrawn from the catholyte gas-liquid separator by means of a catholyte deaerating means, to thereby remove a catholyte dissolved Argon from the hydrogen depleted catholyte, and supplying the degassed hydrogen depleted catholyte to the electrolysis cell stack and/or degassing the oxygen depleted anolyte withdrawn from the anolyte gas-liquid separator by means of an anolyte deaerating means, to thereby remove an anolyte dissolved Argon from the oxygen depleted anolyte, and supplying the degassed oxygen depleted anolyte to the electrolysis cell stack, wherein an amount of dissolved Argon so removed results in the hydrogen having the Argon content of less than 50 ppb (v/v).