|
|
Boeters Ketel Constructie B.V.
Voor het in bedrijf stellen dient de waterkwaliteit aan
de onderstaande norm te voldoen!
The waterquality should meet these standards, noted
below, before operating!
Table 5-1: Feedwater for steam boilers (except attemperator spray
water) and hot water boilers.
|
Parameter |
Unit |
Feedwater for steam
boilers |
Make-up
water for hot waterboilers |
| Operating pressure |
bar (= 0,1 MPa) |
> 0,5 to 20 |
> 20 |
total range |
| Appearance |
- |
clear, free from suspended
solids |
| Direct conductivity at 25° C |
µS/cm |
not specified, only guide
values relevant for boiler water see table 5-2 |
| pH value at 25° Ca |
- |
> 9.2 b |
> 9.2 b |
> 7,0 |
| Total hardness (Ca + Mg) |
mmol/l |
< 0,01c |
< 0,01 |
< 0,05 |
| Iron (Fe) concentration |
mg/l |
< 0,3 |
< 0,1 |
< 0,2 |
| Copper (Cu) concentration |
mg/l |
< 0,05 |
< 0,03 |
< 0,1 |
| Silica (SiO2)
concentration |
mg/l |
not specified,
only guide values for boiler water relevant, see table 5-2 |
- |
| Oxygen (O2)
concentration |
mg/l |
< 0,05 d |
< 0,02 |
- |
| Oil/grease concentration (see
EN 12953-6) |
mg/l |
< 1 |
< 1 |
< 1 |
| Organic substances (as TOC)
concentration |
- |
See footnote
e |
| a With copper
alloys in the system the pH value shall be maintained in the
range 8,7 to 9,2. |
| b With softened
water pH value > 7,0 the pH value of boiler water according
to table 5-2 should be considered. |
| c At operating
pressure < 1 bar total hardness max. 0,05 mmol/l shall be
acceptable. |
| d Instead of
observing this value at intermittent operation or operation
without deaerator if film forming agents and/or excess of
oxygen scavenger shall be used. |
| e Organic
substances are generally a mixture of several different
compounds. The composition of such mixtures and the
behaviour of their individual components under the
conditions of boiler operation are difficult to predict.
Organic substances may be decomposed to form carbonic acid
or other acidic decomposition products with increase the
acid conductivity and cause corrosion or deposits.They also
may lead to foaming and/or priming which shall be kept as
low as possible. |
Table 5-2: boiler water for steam boilers and hot water boilers.
|
Parameter |
Unit |
Boiler
water for steam boilers
using |
Boiler
water for hot waterboilers |
|
Feedwater direct
conductivity > 30 µS/cm |
Feedwater direct
conductivity ≤ 30 µS/cm |
| Operating pressure |
bar (= 0,1 MPa) |
> 0,5 to 20 |
> 20 |
> 0,5 |
total range |
| Appearance |
- |
Clear, no stable foam |
| Direct conductivity at
25°C |
µS/cm |
< 6 000
a |
see fig.
5-1a |
< 1 500 |
< 1 500 |
| pH value at 25° C |
- |
10,5 to
12,0 |
10,5 to
11,8 |
10,0 to
11,0 b, c |
9,0 to 11,5
d |
| Composite alkalinity |
mmol/l |
1 to 15
a |
1 to 10
a |
0,1 to 1,0
c |
< 5 |
| Silica (SiO2)
concentration |
mg/l |
pressure
dependent, according to figure 5-2 |
- |
| Phosphate (PO4)
e |
mg/l |
10 to 30 |
10 to 30 |
6 to 15 |
- |
| Organic substances |
- |
See
footnote f |
| a With superheater
consider 50% of the indicated upper value as maximum value. |
| b Basic pH
adjustment by injection NA3PO4,
additional NaOH injection only if the pH value is < 10. |
| c If the acid
conductivity of the boiler feedwater is < 0,2 µS/cm, and its
Na + K concentration is < 0,010 mg/l., phosphate injection
is not necessary. Under the conditions AVT (all volatile
treatment, feedwater pH ≥ 9,2 and boiler water pH ≥ 8,0) can
be applied, in this case the acid conductivity of the boiler
water is < 5 µS/cm. |
| d If non-ferrous
materials are present in the system, e.g. aluminium, they
may require lower pH value and direct conductivity, however,
the protection of the boiler has priority. |
| e If coordinated
phosphate treatment is used: considering all other values
higher PO4 -concentrations are acceptable (see
also clause 4). |
| f Seee
in table 5-1. |
According NEN/EN12953-10:2003.
|
10-03-2011
We hebben
de afgelopen tijd een paar keer problemen gehad met de
aangeleverde waterkwaliteit voor het afvullen van onze nieuw
geleverde ketels. Vanwege dit probleem, waar nogal eens
gemakkelijk over wordt gedacht, zoals is gebleken, hebben
wij stickers laten maken met bovenstaande tekst. Hierop
staan de NEN-eisen waaraan het water moet voldoen. Wij
zullen deze stickers in het vervolg op onze nieuwe ketels
plakken. De verantwoording ligt uiteraard bij de
waterleverancier. Wij hopen u hiermee voldoende te hebben
geïnformeerd, voor verdere vragen kunt u uiteraard altijd
bij ons terecht. Hier
kunt u eventueel ook de tekst downloaden in PDF.
|
|
