How to avoid fouling, scaling and corrosion in a heat exchanger
In a heat exchanger there are different parameters, which are responsible for the build up of deposits. Water with high TDS or other inpurities cause fouling or limescale crusts at the inner surfaces. Which finally require the heat exchanger cleaning. Some factors can not be directly influenced, whilst using a heat exchanger. These are its construction (plate or tubular), the design of the water loop (material, open/closed system, blow down). Nevertheless they have a significant impact on the cycles for heat exchanger cleaning.
What is important for us at Merus, are the parameters which can be influenced. One of these we focus on is the solubility of foreign substances in the water flow through the heat exchanger bundle. We install one or more of our Merus Rings at the inlet pipes, depending on the size of the heat exchanger system. Sometimes we even install on both sides, the cooling water side and the product side. Doing this we have a far better performance in critical applications.
In effect foreign substances in the water won't settle, but are transported through the heat exchanger without forming deposits. Thus the surfaces stay clean and biofilm, bacteria and other organisms can't stick to the inner pipes. This means that blocked tubes as showed in the picture are not an issue anymore.
As a result cleaning cycles are enhanced significantly and the heat exchanger cleaning is quite simple as there are no hard crusts inside the pipes.
Learn more about how the Merus Technology works in our explanation concerning the function.
Reducing Service Cycles - Results
Over 20 long years we are improving the heat exchanger cleaning. We keep of course track of the improvements. Some of the used data are from the evaluation period after the installation. Majority of the data are from big projects, where we are until today regularily in contact with the customer and control the situation at the heat exchanger. Using parameters as the pressure drop (delta P) or the heattransfer.
In the table below you see the approximate result of heat exchangers, where we are treating the water side. These results where achieved in a system where the cooling water had not more than 3000 TDS and the substances causing the fouling were soluble in the water.
Nevertheless a high TDS is not working against the Merus Technology. We will discuss the expected results with the customer before the installation. To get control of Biofouling, it might not be enough to treat only the heat exchanger. One have to look on the cooling system as a whole.
If we are treating the product side things are far more difficult, see also fouling in an oil application.
Heating and Cooling - Water Treatment for Heat Exchanger and Cooling Loop
Heating and Cooling are often connected and therefore should not be treated as separate systems. Where one medium (water, air) is heated up, the other one is cooled down in the same process step.
With the Merus Technology we treat water, not the devices. Therefore the connection between heat exchanger and cooling (tower) for example in an air condition can be important to detect and locate the problem. If the cooling tower is full of algae and biofilm this can be a hint that there might also be a problem in the heat exchanger.