Large central power stations $($about $1000$ MW electrical$)$ using fluidized bed combustors may be built some day. These giants would be fed $240$ tons of coal$/$hr $(90\%$ C$,10\%$ H$),50\%$ of which would burn within the battery of primary fluidized beds, the other $50\%$ elsewhere in the system, One suggested design would use a battery of $10$ fluidized beds, each $20$ m long, $4$ m wide and containing solids to a depth of $1$ m$.$ Find the rate of reaction within the beds, based on the oxygen used.