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

Water gas is produced when superheated steam is passed over red-hot coke or coal at $1270 \ K$ in the presence of a nickel catalyst:
$C_{(s)} + H_2O_{(g)} \xrightarrow[Ni]{1270 \ K} CO_{(g)} + H_{2(g)}$
It is difficult to obtain pure $H_2$ from water gas because $CO$ is hard to remove. To increase the production of $H_2$,$CO$ is oxidized to $CO_2$ by mixing it with more steam and passing the mixture over an $FeCrO_4$ catalyst at $673 \ K$:
$CO_{(g)} + H_{2(g)} + H_2O_{(g)} \xrightarrow[FeCrO_4]{673 \ K} CO_{2(g)} + 2H_{2(g)}$
This process is known as the water gas shift reaction. The $CO_2$ produced can be removed by scrubbing the mixture with sodium arsenite solution or by passing it through water under $30 \ atm$ pressure,leaving behind pure $H_2$.