Specific Heat Consumption

Dear Experts,

Request your opinion on following 

1. Primary air fan requirement for Petcoke and Coal in % wise or in Nm3/kg cl- which is higher

2. Conveying air requirement for Petcoke and Coal in % wise or in Nm3/kg cl- which is higher

3. % of combustion air in petcoke and coal .firing

as seen Specific heat consumption for Petcoke is higher than Coal owing to finer grinding and sulphur levels. what are the other reasons for higher sp. heat consumption in Petcoke .

your views would help us further.

Regards,

SRP