phosphate dosing in LP steam generators

[amar122amar]

we have 3 LP steam generators (2 in line, 1 standby). there is one phosphate dosing pump. we were doing batch wise dosing in two generators (4 hours in each). Due to batchwise addition, phosphate concentrtion and pH in CBD was fluctuating. we desided to make it continuous dosing. but we are getting different concentration of phosphate and pH value in CBD samples of two generators. this may be slight difference of pressures of two generators. what should be the solution? putting a ristriction orifice in dosing line of generator which is having high phosphate level, throttling the valve? having dedicated pumps? if we changeover the steam generators then...? any permanent solution.please give ur views.

 

[ash9144]

Flow indication and control valves.

 

[amar122amar]

we dont use control valve in any CBD stream.is it used anywhere?

Amarjeet Singh
Reliance Industries Limited

 

[ash9144]

Not on cbd line. Control valve on the phosphate addition.

 

[amar122amar]

Ash9144, phosphate dosing line is 3/4 inch. Pump is PD type. I've seen many steam gens but cv is never used in dosing line or cbd. Dosing is adjusted by pump stroke adjustment.

Amarjeet Singh
Reliance Industries Limited

 

[ash9144]

Ok great you've seen another boiler then you must already have the answer to your question.

 

[amar122amar]

in other boilers there is dedicated pump, but here we have only one pump for two boilers, thats why the problem.

 

[abcmex]

If you have one common boiler feed water supply you may try to dose the additive into the boiler feed water pump suction header. This may distribute the product in a more efficient way.

In each case you could check with a chemical treatment supplier. They are experts in their field (although they may try to sell you their products

rgs

 

[ntq]

You could also inject in the common BFW header before it splits to go to different generators. Also consider adding a static mixer to ensure uniform concentrations.