Water quality of bolier

[fredkfchan]

Dear all,

Can anyone provide some information about the water quality inside a boiler of a CCGT facility. Any good books and standards (British standard, German Standard....) refer to this area.

What are the general parameters which defined the water quality? e.g. Oxygen content, pH, Silica, Fe..........

And also what is the difference between Conductivity and Cation Conductivity?

Thanks

Frederick Chan

 

[MJCronin]

Fred,

An organization called the ABMA ( American Boiler mf'rs Association) publishes a standard detailing boiler water and steam quality.

see page 4 of this .pdf:

http://www.esitenn.com/news/newsletter/issue18.pdf

Also see:

http://www.cip.ukcentre.com/steam.htm

Additionally, your CC steam turbine mf'r may have standards that are different or more restrictive.

MJC

 

[abcmex]

a) You can consult the standard VGB R 450 L (German,

http://www.vgb.org

) for information on Boiler feed water, Boiler water and steam characteristics.

b) ASME has information (

http://members.asme.org/catalog/ItemView.cfm?ItemNumber=I00367)

which perhaps is interesting for you.

Please be aware that the German recommendations (higher requirements) are different than the ASME recomendations.

When you measure specific conductivity you will measure all ions contained in the water. Cation conductivity is measured after a cation ion exchanger

RGS

 

[GBENARD]

Hello,
There is a reference for us which has to be amended according to your plant conditions and the discussions you should have with your boiler and turbine manufacturers. It comes from EPRI and is the counterpart of CS 4629 which is talking about fossil fired plants.

Interim Cycle Chemistry Guidelines for Combined Cycle Heat Recovery Steam Generators (HRSGs)
TR-110051 - 01/28/1998 - 04T079.0.

This is "giving" to you recommendations for water and steam quality in the different nodes, as well as rationales for this, for a CCGT. The only problem is that they are pricing that 12000 USD. Otherwise, you should just follow GE recommandations, they are just following that standard. (you should also have a look on "Steam" from B&W).

 

[iei9596]

Hi,
I hope this will help you

TO ASSURE GOOD QUALITY OF STEAM. S. NO BOILER PRESSURE(PSIG) TOTAL DISSOLVED(TDS) ALKALINITY(PPM) SILICA(PPM)
01 0-300 3500 700 125
02 301-450 3000 600 90
03 451-600 2500 500 50
04 601-750 2000 400 35
05 751-900 1500 300 20
06 901-100 1250 250 8
07 1001-1500 1000 200 2.5
08 1501-2000 750 150 1.0
09 ABOVE 2000 500 100 0.5
ALWAYS KEEP WATER PARAMETERS UNDER LIMITSGET MAXIMUM EFFICIENCY INCREASE YOUR PROFITS
TO ASSURE GOOD QUALITY OF STEAM. S. NO BOILER PRESSURE(PSIG) TOTAL DISSOLVED(TDS) ALKALINITY(PPM) SILICA(PPM)
01 0-300 3500 700 125
02 301-450 3000 600 90
03 451-600 2500 500 50
04 601-750 2000 400 35
05 751-900 1500 300 20
06 901-100 1250 250 8
07 1001-1500 1000 200 2.5
08 1501-2000 750 150 1.0
09 ABOVE 2000 500 100 0.5
ALWAYS KEEP WATER PARAMETERS UNDER LIMITSGET MAXIMUM EFFICIENCY INCREASE YOUR PROFITS



RECOMMENDED ABMA & ASME BOILER WATER LIMITS DRUM OPERATING PRESSURE (psig)
0-300 301-450 451-600 601-750 751-900 901-1000 1001-1500 1501-2000 OTSG
STEAM
TDS max (ppm) 0.2-1.0 0.2-1.0 0.2-1.0 0.1-0.5 0.1-0.5 0.1-0.5 0.1 0.1 0.05
BOILER WATER
TDS max (ppm) 700-3500 600-3000 500-2500 200-1000 150-750 125-625 100 50 0.05
ALK. max (ppm) 350 300 250 200 150 100 Not specified Not specified n/a
TSS Max (ppm) 15 10 8 3 2 1 1 n/a n/a
Conductivity max (µmho/cm) 1100-5400 900-4600 800-3800 300-1500 200-1200 200-1000 150 80 0.15-.25
Silica max (ppm SiO2) 150 90 40 30 20 8 2 1 0.02
FEED-WATER (CONDENSATE & MAKEUP, AFTER DEAERATOR)
Dissolved Oxygen (ppm O2) 0.007 0.007 0.007 0.007 0.007 0.007 0.007 0.007 Not sensitive
Total Iron (ppm Fe) 0.1 0.05 0.03 0.025 0.02 0.02 0.01 0.01 0.01
Total Copper (ppm Cu) 0.05 0.025 0.02 0.02 0.015 0.01 0.01 0.01 0.002
Total Hardness (ppm CaCO3) 0.3 0.3 0.2 0.2 0.1 0.05 None detected None detected None detected
pH @ 25º C 8.3-10.0 8.3-10.0 8.3-10.0 8.3-10.0 8.3-10.0 8.8-9.6 8.8-9.6 8.8-9.6
Nonvolatile TOC (ppm C) 1 1 0.5 0.5 0.5 0.2 0.2 0.2 None detected
Oily Matter (ppm) 1 1 0.5 0.5 0.5 0.2 0.2 0.2
MAKE-UP AT 0.5% BLOWDOWN
TDS 11.4 9.8 8.1 6.5 4.9 3.3 0.5 0.3
Silica (ppm SiO2) 0.75 0.45 0.2 0.15 0.1 0.04 0.01 0.005
MAKE-UP AT 1% BLOWDOWN
TDS 22.8 19.5 16.3 13 9.8 6.5 1 0.7
Silica (ppm SiO2) 1.5 0.9 0.4 0.3 0.2 0.08 0.02 0.01
MAKE-UP AT 2% BLOWDOWN
TDS 45.5 39 32.5 26 19.5 13 2 1.3
Silica (ppm SiO2) 3 1.8 0.8 0.6 0.4 0.16 0.04 0.02
MAKE-UP AT 3% BLOWDOWN
TDS 68.3 58.5 48.8 39 29.3 19.5 3 2
Silica (ppm SiO2) 4.5 2.7 1.2 0.9 0.6 0.24 0.06 0.03

 

[EMKWR]

Fred,

to get a proper idea about the conditioning regime, you first have to tell more about the type of boiler (pressure, temperature, what materials is the boiler including the condensor made of etc.). Then of course there is the question which quality of water you produce in your demin plant (take care of silicate, chloride, TOC etc).
There are several regimes available to choose from. You can use simply ammonium as conditioning agent (all volatile treatment), or if you have an extremely good quality water you can use combined treatment (oxygen and ammonium) or even oxygen treatment.

Take one advise from me, avoid organic amines. These will decompose in organic acids which will return in the first condensate on your turbine blades.

My company (KEMA) has issued its own guidelines for water/steam conditioning. The requirements are even higher than the German (VGB) ones but they have resulted in an extremely low number of problems in the Dutch power plants.

If you want more information, just ask.

Best regards,

Edwin

Edwin Muller
KEMA Power Generation & Sustainables
Arnhem, The Netherlands
E-mail e.f.muller@kema.nl
Internet:

http://www.kema-water.nl

http://www.kema.com

 

[EMKWR]

Fred,
forgot part of your question. Cation conductivity is the conductivity after passing a cationic ion exchanger. It is a more sensitive reading than conductivity (a hydronium ion has a larger specific conductivity than the other ions.
If you like advise on treatment of your boiler feed water, offer more details. Since it strongly depends on the boiler design, I cannot give you general advise.

Best regards,
Edwin

Edwin Muller
KEMA Power Generation & Sustainables
Arnhem, The Netherlands

 

[carlosc]

It is very important that you verify your ST requirements. Most of the time you have more restrictios with steam quality in the ST that in the HRSG or in the Boiler. The Siemens-Westinghouse clas G (gas turbines) also will require an exceptional steam quality for cooling in the TP and Total Volatil treatment (No Phosphate)
SiO2< 5PPB;
Cation Cond < 0.2umhos
Sodium <5 PPB and very low levels of Iron.