$(14$ points$)$ The initial moisture conteat of a certain wet material is $64b,$ and

after drying, the moisture eontent is $196($iev wet basis$).$ The processiag

capacity of the wet material is $0\mathrm{.}6k\frac{g}{h},$ and the initial temperature of the air

is $20C.$ The initial moisture conteat is $0\mathrm{.}005kg$ of waterike of dry ain

Asuming that all moisture is removed during the surface gasification stage.

the drying equipment is well iasulated, and the outlet temperature of the air

is solected as $70C.$ If preheat the air to $150C,$ how maeh heat is eseded?

What is the thermal effeiency: