In the countries having developed industry the majority of the industrial water  - depending on the sector - 35-90 % is utilized in the form of cooling water. Also a significant quantity of water consumption is used for steam generation, as well as the water supply of central heating systems and air conditioning equipment. In most cases the heat transport takes place through the heat-transfer surface (appliance wall) and it its totality it can be characterised by the extent of heat transmission (K). The provision of the optimum conditions of heat transport if fundamentally a technical-economic problem, but it has serious safety engineering concerns too.

What causes the problem?

The improperly treated water flows, and those contaminated in the course of multiple use can create deposits of diversified composition and morphology on the heat-transfer surface, the heat-transfer resistance of which is much greater than that of the clean structural material.
Some examples as a quantitative illustration of the above:

Concerning their nature the deposits are scales of various type, suspended matters, oils various corrosion products (iron oxides), and the combinations thereof. Due to the extremely high heat-transfer resistance of the settled contaminations the heat transmission drastically reduces, the appliance uneconomically operates, and then it becomes unable to fulfil its original task. In case of boilers explosion risk exists due to the local overheating and possible scale separation.

Can this problem be evaded?

The brief answer: NO!
In ideal case the quality of the cooling water should be near that of the drinking water, but it is too expensive and not justified. In case of boiler feed-water the requirements are even more strict. The components causing deposits are originally present in the cooling water, and/or they get in it anyway.

Suspended matters:

They are of organic and mineral origin. The particle under 30 mm cannot practically be settled in the course of pre-treatment, they thicken, agglomerate during the recirculation, and they stick at the locations favourable from the point of view of hydrodynamics, possibly in a structure joint with the scales.
In the course of the air-recooling of the cooling water in open system, approx. 1000 m3 cooling air is required for 1 m3 water, the dust content of which is transferred to the cooling water by washing over (5 to 15 g dust pollution per hour calculated for 1 m3 cooling water).
In cooling elements of low wall temperature, recirculated cooling water system the excess growth of algae occurs frequently, which create carbohydrates, greases, proteins using light energy, and then when they die, they increase the amount of suspended matter content.
During the cooling of machines, appliances oil- and grease contaminations may get into the water on the suspended matter surface of which and on the appliance wall they stick causing hard-to-remove deposits.

 

Scale formation:

Formation of carbonate scale Ca(HCO3)2
The scales of other type (sulphate, silicate, phosphate) are formed due to polluting gases washed out from the air (e.g. SO2), and/or the chemicals used for treating the cooling water.

Corrosions products:

First of all secondary deposits of iron oxide nature, in which wüstite, magnetite and haematite occur. Their formation during operation originates in the effect of chemicals used in the modern water treatment technologies.

What to do?

The factors affecting the formation of deposits are usually given (appliance geometry, flow conditions, wall temperature, pH), so the optimisation of the operation can be hard-to-implement or impossible in practice. At the same time with due attention the operator can record - through the change of the characteristic technical parameters, - when the equipment reached the critical level of contamination. Following or even preceding this the appliances should be cleaned or be made cleaned. Regarding that most of the operators do not have sufficient experience and outfit it is expedient to entrust it to a specialized expert.

How do our experts work?

They assess the nature and extent of the contamination with a quick on-site analysis after the sectionalisation of the appliance to be treated.
Having this knowledge they determine the chemical combination to be applied and the required active agent content, as well as the required working temperature and the expected duration of the treatment.
During the chemical-technical cleaning they regularly check the critical parameters (acid concentration, inhibitor effect, pH).
After the completion they restore the original technology condition, they document the work performed.
The work of our experts is characterised by quickness, effectiveness, complexity and last but not least reasonable prices.

Scale of considerable amount next to a cleaned cooling tower

In case of cooling towers the deposited scale amount entails a large electricity bill, not to speak about the fact that the cooling becomes insufficient due to the decrease of efficiency, which may be critical in case of many industrial applications. It is better to prevent the trouble through regular cleaning and maintenance, replacement of worn cooling elements, which our experts carry out with established knowledge. Regardless of the make, design, size of the cooling tower, Heves Cleaning Kft. can revitalise your cooling tower.