7 replies to this topic

[process En]

Is it possible that TH in Boiler feed water was higher than TH in conteneous blowdown for boiler which in in service with load=125 t/h,P=45 barg.
otherwise;could anybody advise me for discussing with water specialist?

[ankur2061]

Is it possible that TH in Boiler feed water was higher than TH in conteneous blowdown for boiler which in in service with load=125 t/h,P=45 barg.
otherwise;could anybody advise me for discussing with water specialist?

Your question is very general. Please specify data for total hardness in both the BFW (Boiler Feedwater) and the CBD (Continuous Blowdown) from your boiler.

Also are you familiar about how to calculate the BFW and Blowdown rates given the steam production rate and the inlet TDS (total dissolved solids) from BFW as well as the TDS in the Blowdown.

Regards,
Ankur.

[joesteam]

Unless you have contaminated boiler feedwater, like from a leaking heat exchanger or some other way 'bad' water can enter this system, it is impossible for the feedwater TH to be greater than the boiler TH, because the boiler water is cycling up in concentration.

[process En]

Unless you have contaminated boiler feedwater, like from a leaking heat exchanger or some other way 'bad' water can enter this system, it is impossible for the feedwater TH to be greater than the boiler TH, because the boiler water is cycling up in concentration.

Dear Joesteam;
How can I confidence that the only reason could be Process leackage?(Is there special procedure?)



Results;
TH in BFW is 1.08 and 1.02 mg/L
TH in CBD is 0.66 /0.51 and 0.9 mg/L

[ankur2061]

Unless you have contaminated boiler feedwater, like from a leaking heat exchanger or some other way 'bad' water can enter this system, it is impossible for the feedwater TH to be greater than the boiler TH, because the boiler water is cycling up in concentration.

Dear Joesteam;
How can I confidence that the only reason could be Process leackage?(Is there special procedure?)



Results;
TH in BFW is 1.08 and 1.02 mg/L
TH in CBD is 0.66 /0.51 and 0.9 mg/L

process En,

Joesteam is right. Due to concentration of cycles the normal phenomena is to have higher TDS in CBD then in BFW. There could be another posibility that your TDS are being carried over into the steam which is a very undesirable phenomena. You could take a sample of your steam and check it out since your TDS material balance needs to check out which means:

TDS in BFW = TDS in CBD + TDS carried over over with steam.

Hope this helps.

Regards,
Ankur.

[joesteam]

I forgot about carryover, getting high TDS liquid leaving the boiler with the steam. but even if you have 100% carryover, the TDS of the condensate still would not be higher than in the boiler itself.
I still say start looking for contamination, taking hardness readings in different areas of the facility until you can find the source.

[Satyajit]

Hi,
There could be another possibility that you have much higher Continuous blow down than theoretically ( 2% of BFW flow rate) done.

Please check your IBD valve, is it passing ?

Kind regards,
Satyajit