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Fouling Heat Exchanger stopped and removed


  The fouling of Heat Exchangers and the resultant cleaning of Heat Exchangers is a common task in many companies. Unfavorable water, high temperatures and impurities in the water are the main reasons for fouling in Heat Exchangers. Fouling in a Heat Exchanger causes less performance in the heating or cooling process. The more fouling is found, the worse the internal heat transfer will get. In tubular Heat Exchangers the fouling happens as well on the tube side as on the shell side of the Heat Exchanger. In a water/water Heat Exchanger the fouling happens on the tube and the shell side in the same way. But in most cases there is water on one side of the Heat Exchanger and product on the other side, either to be cooled or heated.
Depending on the kind of product often the fouling in the Heat Exchanger is on the product side worse than on the water side. As can be seen on the picture the fouling happens first in the pass on the top left, where it is hottest and over time the fouling is happening in all passes.

Mostly responsible for fouling on the water side of a heat exchanger are scaling, corrosion and often also micro organism causing biofouling. The scale is formed mostly by salts solved or solids carried in the water, the corrosion is caused by aggressive water and the bio fouling is caused by algae or bacteria in the water which are forming a biofilm at the surfaces of the Heat Exchanger.

So in a lot of cases where heavy fouling happens in the Heat Exchanger, these have to be cleaned regularly. In order to clean a heat exchanger, the production has to be stopped, the heat exchanger has to be disassembled, and cleaned either manually or by the use of chemicals. To clean such a big heat exchanger, as shown on the picture, easily 2 or 3 days are required.

PursanovaTM is able to stop the fouling altogether in the Heat Exchanger or at least reduce it significantly. This is done by installing a PursanovaTM Disk at the inlet line of the Heat Exchanger, where the problem is found. If there is fouling on both side of the Heat Exchanger a PursanovaTM Disk has to be installed in each line. In the case several heat exchangers have to be taken care off and also the cooling loop has to be treated, it is most times not required to install a PursanovaTM Disk at each feed line of the Heat Exchanger, in such cases there will be several ring installed in the loop, and only on very critical Heat Exchangers there is a PursanovaTM Disk required direct ahead the single Heat Exchanger. As it is not possible to open the heat exchanger to check about the performance we are using the heat transfer coefficient to check the performance. To find a tool to calculate the heat transfer please click.

PursanovaTM is able to improve all cases of fouling, where the material which causes the scale is soluble in the liquid. In the case of water this is for instance lime scale, which is soluble in water. PursanovaTM is increasing the solubility, in some cases, up to more than 10 times its former value. In the case of product, e.g. chemicals or crude oil, the same thing is possible, but to what extent, we cannot tell without a trial.

Currently PursanovaTM is doing automatic cleaning of Heat Exchangers. This we have proven in a lot of cases, where almost fully blocked Heat Exchangers got cleaned after some time by themselves. The fouling of the Heat Exchanger is stopped and at the same time, existing scale is removed. For further information you can check the case studies, how it is done in refineries with scale or corrosion, with biofouling, at chemical plants or in hot water boilers in a public swimming pool in Munich