How can production of hydrogen from water gas be increased by using water gas shift reaction?

Water gas is produced when superheated steam is passed over red hot coke or coal at 1270 K in presence of nickel as catalyst.
C(s)Coke+H2O(g)Steam+121.3 kJNickel1270 KCO(g)+H2(g)Water gas
It is inconvinient to obtain pure H2 from water gas as CO is difficult to remove. Hence, to increase the production of H2 from water gas, CO is oxidised to CO2 by mixing it with more steam and passing the mixture over FeCrO4 catalyst at 673 K.
CO(g)+H2(g)Water gas+H2O(g)SteamFeCrO4673 KCO2(g)+2H2(g)
This is called water-gas shift reaction. Carbon dioxide is removed by scrubbing with mixture of sodium arsenite solution or by passing the mixture through water under 30 atm pressure when CO2 dissolves behind H2 which is collected.