However, the actual catalyst employed in WGSreaction has a mild catalytic activity at the above specified temperatureso it is difficult to reach the reaction equilibrium state, which in turnmay lead to higher CO concentration than the calculated value. Inaddition, the concentration of N2 at the exit of the PrOx reactor, whichis also higher than the calculated value, is related to the higher CO concentration at the exit of the WGS reactor because the air flow fed intothe PrOx reactor is increased to remove CO from the WGS reactor outlet