please help with a. answer for a should be around 220871 m3/h

A process gas stream with a flowrate of 826m3/s at 07fegC and 1 atm is to be incinerated-at 1038 degC in an oxidiser of dimensions: 9.1m9.1m12.1m. Natural gas is to be employed using primary air. The stoichiometric combustion of natural gas produces 11.4kgmol flue gas/kgmol natural gas. The heat available from natural gas is 19772kJ/m3 at 1038degC. Assume that the process gas stream has properties of air. Calculate: a. The required natural gas flowrate b. Does the unit meet the required residence time of 0.7s