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

Explanation

Dihydrogen is produced by coal gasification method as:
`underset("coal")(C_(s))+H_(2)O_(g) overset(1270K)to CO_(g)+H_(2)(g)`
The yield of dihydrogen (obtained from a coal gasification) can be increased by reacting carbon monoxide (formed during the reaction) with steam in the presence of iron chromate as a catalyst.
`CO_(s)+H_(2)O_(g) underset("Catalyst")overset(673K)to CO_(2_(g))+H_(2_(g))`
The reactio is called the water gas shift reaction. Carbon dioxide is removed by scrubbing it a solution of sodium arsenite.