Boiler main steam temperature

PA/ SA - What is PA? What is SA?

PA is primary air given for main combustion to take place. SA is secondary or territory air given to accomplish the staged combustion. Primary air goes to fluidise the bed inventory and secondary air is admitted at a particular height in the furnace.

How does PA/ SA air flow distribution in CFBC boiler affect main steam temperature.

First of all on such a complex system you are not detailing the boiler size, the working pressure & temperature, what is the plant designed for, power only then how much MW, power + steam from process then how much, coal quality mosisture, calorific value, sulphur , ash etc etc.

In absence how do you expect one to answer you.

Do you have a combustion analyzer to check the Air/Gas ratio for complete combustion? What condition of sooth formation in the super heater? Any cfm meter and records for both PA/SA air flow in conjuction with the Fuel/air ratio?

Badly fouled superheaters with incomplete combustion will affect the steam temperature at the outlet.

Consider the purchase of the fine text "Steam" by B&W... well worth the money charged.

Consider taking the time to read it, understand it... and then come back with a more complete question

Steam temperature is dependent on boiler pressure and super-heater (mass) flow.

Is your concern 1) How much primary air air do I need to lift the fuel for good mixing, to prevent stagnation. 2) How much secondary air to I need for complete combustion (excess 02).

Without complete combustion you may get to temperature, but not carry the load.