+49 6203 6204 654  Wallstadter Str. 59, D-68526 Ladenburg, GERMANY

Cooling Water

VDI 2047

  • Legionella

  • E.Coli

  • Pseudomonas aeruginosa

The cooling medium water often leads to considerable corrosion in cooling circuits. The quality requirements imposed on the cooling water are often of a contradictory nature and accordingly often differ.

Appearance: as far as possible colorless, clear and without sediment
pH value: 7 to 8.5 (no contact of the aluminum components with the water pH to 9.0)
Conductivity: <3000 S / cm = 300 mS / m
Total hardness: <60 dH after softening: <20 dH
Carbonate map: <4 dH (<0.7 mol / m3) after hard stabilization: <20 dH
Total salt content: <1800 mg / l
aggressive carbonic acid: 0 mg / l
Calcium:> 20 mg / l
Iron: <0.1 mg / l
Chloride: <250 mg / l
Sulphate: <600 mg / l
Germ count: <10,000 CFU / ml
Legionella: <100 cfu / 100 ml
KS 4.3: <1.4
after hard stabilization: <7

Too high hardness in the feed water, this is either softened to avoid deposits or conditioned by the addition of chemicals. The pure water withdrawn from the circulation by evaporation inevitably leads to a concentration, which is further increased by additional salt entry through the feed water. To avoid precipitation, encrustation and corrosion, the salt content must be kept within certain limits, which is usually done by desalination of the concentrated recirculating water and desserts of fresh water. The aforementioned limit values must be observed in the circulating water. When using partially / completely desalinated make-up water, it may be necessary to use a suitable corrosion inhibitor. Regardless of the additional water quality, the system thickening of EZ = 6-8 should not be exceeded.

Chloride:
The chlorides exert a significant influence on the corrosion behavior of a water. Since they can not be eliminated from the water by simple dropping methods, their concentration is maintained by means of blowdown in the range of 250 mg / l. They are highly corrosive to many metals, including stainless steel, and cause pitting. The higher the temperature, the stronger the corrosive effect.

Sulfate:
They also lead, like the chlorides, to corrosion on metallic materials, although not quite as strong, which is why in practice a value of 600 mg / l sulphate should not be exceeded.

carbonate:
The dissolved in the form of bicarbonates calcium and magnesium compounds cause, also referred to as temporary hardness, carbonate hardness. When changing the lime-carbonic acid balance (pH increase, heating with the result of increased CO2 discharge) form sparingly soluble carbonates (scale).

Total hardness:
Total hardness is defined as all compounds of calcium and magnesium contained in the water, that is to say not only the carbonates but also the sulphates, chlorides, etc.

TDS:
The sum of the substances dissolved in the water forms the total salt content. It can be determined by a comprehensive analysis of the compounds present in the water.

Surface tension:
The surface tension of water is given in (sigma). In order to ensure the effectiveness of the mist eliminators and fillers, the value should be 60 mN / m.
The limit values for the discharge of wastewater must be taken into account as well as any existing environmental protection requirements.

NonaChem GmbH
Wallstadter Str. 59
D-68526 Ladenburg
GERMANY

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