Hello,
Good day everyone.
I'm currently working in a coal fired power plant industry with boiler pressure around 206 bar (HP, IP, and LP turbines). Today, the power plant is at its commissioning stage and I only provide support to the commissioning team such as review of documents needed for turn-over. I belong to the operations team particularly the boiler dosing, water treatment system and the laboratory department.
I would just like to ask an opinion and if there's any solid references which I could read regarding the proper dosing location of phosphate particularly sodium tripolyphosphate.
Here in our plant the dosing is located at the economizer inlet. As much as I am concern, my partial reference such as the GE Power and Water (Water & Process Technologies) states that phosphates are usually fed directly into the steam drum of the boiler. It has also been emphasized that polyphosphates must not be fed to the boiler feedwater line when economizers, heat exchangers, or stage heaters are part of the preboiler system. As presented by one of the references by Byworth Boilers: where an economizer or feedwater pre-heater is used they should be dosed directly into the boiler shell, this is to prevent deposition on the heat transfer surfaces. The information which I have are contradicting to the location of dosing point here in our plant which is at the economizer inlet.
Can someone help me with this concern? So that I could address it also to our management and do some necessary revisions if there's any solid information I could share to them
Hoping for a positive response.
Thank you in advance.