ICI Caldaie ECOVAPOR Series, Инструкция по установке, использованию и техническому обслуживанию

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First commissioning
51
WATER CHARACTERISTICS
The values in the following tables are taken from tables 5.1 and 5.2 of EN 12953-10 (requirements for water delivery and water
inside generator).
Even for the generators not included in the mentioned standard, it is nevertheless necessary to adopt at least the indicated limits
and consult specialised companies to select the type of treatment to be carried out based on a comprehensive analysis of the
available water.
Water delivery - Limit values (at inlet)
CHARACTERISTICS u.m. Steam generator water with pressure up to 20 bar
Appearance Clear, limpid, without foam or suspended solids
Direct conductivity at 25°C μS/cm See table values "Operating water - threshold values"
pH at 25 °C [a] --- > 9,2 [b]
Total hardness (Ca+Mg) mmol/l < 0,01 [c]
Iron (Fe) mg/l < 0,3
Copper (Cu) mg/l < 0,05
Silica (SiO
2
) mg/l See the "Maximum acceptable silica content in the generator water up to 20 bar pressures" table
Oxygen (O
2
) mg/l < 0,05 [d]
Oily substances mg/l < 1
Concentration of organic substances - See note [e]
[a]
With copper alloys in the system the pH value must be kept within 8.7 and 9.2.
[b] With a softened water pH value > 7.0, the value of the generator water pH should be provided based on the chart
“Operating
water - limit values”
.
[c]
At operating pressure <1 bar, a maximum total hardness of 0.05 mmol/l must be acceptable.
[d] Instead of respecting this value with intermittent operation or operation without deaerator, in case of agents forming the film
and/or excess of oxygen, the additive must be used.
[e]
The organic substances are generally a mixture of several different compounds. The composition of these mixtures and the
behaviour of their single components at the operating conditions of the steam generating system are difficult to predict. The
organic substances can be decomposed to form carbonic acid or other acid decomposition products that increase the acid
conductivity and cause corrosion and deposits. They can also lead to the formation of foam and/or to the production of steam
with suspended water that has to be minimised as much as possible.
Maximum acceptable silica content in the generator water up to 20 bar pressures
Alkalinity Silica
0,5 mmol/l 80 mg/l
5 mmol/l 105 mg/l
10 mmol/l 135 mg/l
15 mmol/l 160 mg/l
Note
These values apply supposing the presence of a thermal deaerator. If no deaerator is present, the temperature of the water
contained inside the reservoir must be increased to at least 80 °C in order to reduce the content of dissolved gases (O
2
and CO
2
).
In any case, it is recommended to use chemical conditioners to completely deoxygenate the water delivery and to minimise the
corrosive effects of CO
2
.
5.2 Operating water - threshold values
CHARACTERISTICS u.m.
Steam generator water with pressure up to 20 bar
Water delivery direct conductivity > 30 μS/cm Water delivery direct conductivity ≤30 μS/cm
Appearance Clear, limpid, without foam or suspended solids
Direct conductivity at 25°C μS/cm < 6000 [a] < 1500
pH at 25°C --- 10,5 - 12 10 - 11 [b] [c]
Composite alkalinity mmol/l 1 - 15 [a] 0,1 - 1 [c]
Silica (SiO
2
) mg/l See previous table "Maximum acceptable boiler water silica content up to pressures of 20 bar"
Phosphates (PO
4
) [e] mg/l 10 - 30 6 - 15
Organic substances - See note [d]