PH OF FEED WATER COMES DOWN IN STEAM DRUM

[pradeep4u]

Dear All
I want to know that why after dozing ammonia or morphiline at upstream of deaerator we doze trisodium phosphate in steam drum to increase PH . Whether PH of water comes down when water reaches boiler then how PH reduces?
Regards
Pradeep

 

[Dhurjati Sen]

Hi Pradeep,

Why do we dose hydrazine / sodium sulphite at de-aerator upstream?
Its oxygen scavenger from the boiler feed water.

Why do we dose morpholine at de-aerator upstream?
It removes carbon dioxide from the boiler feed water.

Why do we dose sodium tri-phosphate in the steam drum?
There are some salts like calcium carbonate that have inverse solubility, i.e. they get deposited as the temperature goes up. Na3PO4 reacts with them to form salts which do not have inverse solubility. These are removed thru continuous and intermittent blowdowns, etc. etc.

Happy reading.

DHURJATI SEN