How can the production of dihydrogen,obtained from 'coal gasification',be increased?

(N/A) Dihydrogen is produced by the coal gasification method as:
$C_{(s)} + H_2O_{(g)} \xrightarrow{1270 \ K} CO_{(g)} + H_{2_{(g)}}$
The yield of dihydrogen can be increased by reacting the carbon monoxide formed during the reaction with steam in the presence of an iron chromate catalyst. This is known as the water-gas shift reaction:
$CO_{(g)} + H_2O_{(g)} \xrightarrow[FeCrO_4]{673 \ K} CO_{2_{(g)}} + H_{2_{(g)}}$
In this process,carbon dioxide is removed by scrubbing the mixture with a solution of sodium arsenite.