Solutions to problems of corrosion & fouling

Below is a list of applications where our clients had problems with rust, corrosion lime scale amd bio-fouling. As usual Merus Technology was the Solution to each Problem.

As no two systems are ever exactly the same, results will vary from application to application. Flow characteristics, temperatures, electrical installations and varying water qualities each have an influence on the quality of the results and the time it takes to achieve these results. Some system types will take longer than others to observe results. In many cases results may be observed at around 30 – 50 days. Sometimes results are as fast as 2 weeks. The point is that different applications behave differently.

Semiconductor company, South Korea

The Problem

A lot of steam is required to manufacture microchips. This steam is produced in several big steam boilers, and distributed to separate buildings of the plant. The system design is to return condensate to the boilers to be reused to produce more steam. The condensate system at Hynix is several kilometres long and has started to corrode. Measurements of the condensate have an average of 2,5ppm iron shown. The internal quality requires feed water for the boilers with an iron content of less than 0,1ppm. Because the iron content is too high the condensate cannot be reused. Several 100m3 of condensate per day had to be wasted.

The solution

Merus was installed at several locations on the system. During the test, other rings were added to get a satisfying result.

The Result

The iron content in the condensate was regularly checked by the laboratory of the client. The first weeks after the installation, not much difference could be seen. All of a sudden, the iron content increased significantly. Over the next several months of operation the iron in the condensate got less and less, until the value has stabilized at an average of 0,05ppm iron.

  • Condensate can now be reused to produce new steam saving several 100m3 of condensate per day.
  • Energy savings for heating the water
  • Significantly less Chemical usage

Coca Cola Company

The Problem

The client uses a closed loop for cooling down the mould forms for production of PET bottles. The water is cooled by a plate heat exchanger. Due to a little leacking of the loop,This is also continuously introducing new lime scale as well as new oxygen into the loop. Causing corrosion,. The loop has to be cleaned on average every14 days. Mostly rust and a little scale. This leads to significant costs, not only the cleaning time and the chemicals used, but also in terms of shutting down the production for several hours. This cleaning was not always possible, and this leads to further serious quality problems in the bottles.

The Solution

We installed one Merus®-Ringe in the cooling loop. In between the heat exchanger and the moulds at the machine. It was installed very near to the mould forms, in order to get the best possible results in the forms.

The Result

From the time of installation there were daily samples of water taken, which was checked for iron content by the companies lab. In a closed loop it was expected, that the iron content in the water would increase, but due to the small leakage, the rust and the scale was being drained from the system as well. So it could bee seen, that the iron content in the water decreased steadily and stabilized on a very low and acceptable value.

Since then it could be seen by several inspections, that there was no corrosion or lime scale in the mould forms at all. As also there was no need of chemical cleaning. The big advantage for the client, was not only that the quality of the PET bottles is constantly high, but now there is no shutdown in production.

Chemical Company, Cairo Egypt

The Problem

In the chemical industry significant amounts of steam are needed for different processes. This client uses several boilers, with a total capacity of more then 100m3 per hour. The feed water is treated chemically. The demineralised water becomes aggressive and together with the high temperatures inside the boiler corrosion starts at all surfaces in contact with the water. The client regularly added inhibitors to prevent corrosion. Study shows that even by using chemicals, corrosion still occurs. Iron or rust in the steam will cause further corrosion in the pipe systems and this leads to a shorter lifespan of equipment.

The Solution

A Merus ring was installed at the feed pipe of the boiler. In the first weeks there no change in the use of inhibitors against corrosion

The Result

The iron content in the steam and the Blow down pipe was regularly checked. The iron in the steam became less and less, and finally stabilized on a very low level. Adding inhibitors didn’t stop until 6 weeks after installation. This was also the regular production break where service is carried out on the boiler. On visual recorded inspection, it was seen, that most of the surface was now black, coated with saturated iron oxide, only a few red spots of red rust was observed, and it was expected these would disappear too. After witnessing this result the client decided to stop adding corrosion inhibitors. The steam is still regularly checked for iron.
  1. No more chemical dosing.
  2. No more chemical cleaning costs
  3. No mechanical cleaning costs.
  4. Corrosin has stopped, no more rust or scale
  5. Internal surfaces protected by black oxide.
It is assumed that the lifespan of the system has now also increased dramatically.

International Hotel – Indonesia

The problem

Limescale was a big problem in the dishwashers. The maintenance personnel carried out a chemical cleaning every month.

The Solution

Two Merus rings were installed around the main cold and hot water pipe of the dish washers and around the corresponding feed lines of the washing machines.

The Results

  1. No new limescale develops on the inner walls.
  2. The limescale crusts in the washing machines started to soften. At the same time the deposition of new limescale stopped.
  3. The washing machines never had to be cleaned chemically again.
  4. After the first positive experiences it was decided that no more fabric softener should be used and still the laundry came out of the washing machines as soft as before.
  5. Furthermore it was observed that new towels which didn’t use to become soft right after the first wash, become soft immediately now and can be used instantly instead of having to be washed at least twice before being used.

Legionella in residential home for the elderly: Munich

The Problem

Due to extremely high legionella values the health authority shut down the sanitary equipment in a nursing home, which was built in the 1970s in three phases of construction with a total of almost 300 apartments. After repeated decontaminations by means of heat the legionella contamination increased again very quickly. The costs: several ten thousands of euros.

The solution

At first Merus was only installed at the inlets to the building and behind the hot water tank.

The Result

Shortly after the installation was completed the CFU – values dropped by about 80%. After three more months the numbers dropped further everywhere with the exception of a little used area.

This little used area had only slightly increased numbers in its recorded values. A further ring was placed in this part of the system. About one year later the water in this area also conformed to the compulsory limit value of 1000 CFU/l.

The rest of the system had reached compulsory value after only 6 months. Today, this building is considered to be free of legionella and no longer is on the watch list of the health authority.

Fresh & Waste-Water company (DEYA). Chrissoupolis, Greece

The Problem

In the village the supply of fresh water steadily decreases. Limescale clogs the pipes and the diameter decreased so much that in some parts of the village only very little water reached the household. DEYA was forced to take action. There were two possibilities. Either change the whole pipe system, which was not possible for economic reasons, or try to locate the spots where the problems urgent and replace part of the system. This method is also very expensive and the problem is never really fixed until eventually all of the system has been replaced anyway.

The Solution

In one part of the town where the problem was the worst and almost no water reached the houses, one 2″ Merus® ring was installed. The pipe was checked before and the documented.

The Result

Four months after the installation the pipe was FREE FLOWING again. The limescale had totally disappeared. The pipes were completely cleaned, and smooth metal could be seen. There was no sign of corrosion at any inspection points.

Even if the total system had been renewed, it would be in the same lime scaled condition at some point in the near future. Merus® is a permanent solution. Now the water supply for all users in this area is perfect. In all parts of the system pressure has returned again.

There is no data from the households in this area, because DEYA was interested in their own systems not the house holders. Nevertheless there were several positive comments from the users in the community.

Paper and Pulp Industry

The Problem

The feeding water of the steam boiler is rather soft, so the client decided out of economical reasons, to use city water, instead of an expensive and service intensive chemical treatment. So the steam boiler had to be chemically cleaned each summer. The coils especially had a thick layer of lime scale. This chemical cleaning was expensive and time consuming. The chemicals also damaged the internal surfaces of the machinery, which leads to additional corrosion.

The Solution

Approximatelly three month after the last chemical cleaning, one Merus®-Ring was installed at the feeding pipe of the steam boiler. At this time the performance of the boiler already started to drop as it usually did at this time.

The Result

  1. In the beginning it could be seen at the blowdown pipe, that the water contained small particles of lime scale. The particles got less with the ongoing cleaning of the boiler during the normal operation.
  2. The performance of the steam boiler was raised. Not only was the total amount of steam increased again, but the time taken in the morning to bring the system up to pressure was significantly shortened.
  3. At the next inspection of the boiler the following summer, there was no lime scale at all. This was the first time since the system started operating that there was no chemical cleaning necessary .

Cement production company

The Problem

The client uses a cooling loop for several big motors, which is fed by three independent 4” inlet pipes. The scale has reduced the diameter of the pipes so much that that the pumps were working over their capacity and the amount of cooling water which has reaching the motors was not sufficient anymore, to ensure adequate cooling. Heat transfer also occurs in the motors and because of scale build up, the efficiency was low. Scale build up of only 1mm can increase energy requirements by as much as 11%.

The Solution

Three 4″ Merus® rings were installed, one on each inlet pipe of the loop. In this way it was possible to treat all the incoming water and the whole cooling loop.

The Result

  • On the day of the installation, a connector of the pipe was opened. There was a lot of lime scale observed. After two months of operation the same part was opened again. More than half of the scale was gone. Only little pieces of scale where left on the pipe walls which would also disappear soon. This shows, that in only a few month a whole system, can be cleared of centimeters of lime scale
  • After a few weeks the cooling efficiency of the motors rose significantly. This means the scale from the heat exchanger had disappeared as well.surfaces where the heat transfer in the motors take place where cleaned as well.

Dyeing and textile industry

The Problem

This is a typical case, where the client didn’t even know he had a problem to begin with. The firefighting system covers the whole production area. The system is always under pressure, so that in an emergency there is enough water to fight a fire. During services where some valves were opened, it could be seen that there was corrosion in the pipes. This leads to the risk, that in the case of fire, the rust particles will clog the spray nozzles of the system and not enough water can flow.

The Solution

One 3″ Merus® ring was installed. At the feeding pipe of the fire fighting system, before the regular valve and the pumps. The Trial Target was to remove the existing corrosion and prevent the system from further corrosion, by flushing out the rust.

The Result

Directly after the installation a sample was taken at a shut off valve as far as possible away from the inlet. This was done slowly, so the water was mainly clear. Some days later a second sample was taken at the same place and under the same condition. This time the water was dark brown. In the sampling bucket, there was a thin layer of rusty particles to be seen. The client wouldn’t believe, how much rust was in the system and how well the Merus® ring was working in such a short time. The system was cleaned by flushing water at several points in the system, until it became clean. This was done four times, until no more brown water present. These days Sprinkler systems are a very common application for us. It has shown that this test is one of the fastest ways to show the client how efficient the Merus® technology is.

Food Production Company Germany

The Problem

Sauerkraut and other food are packed in canes. This machine needs constant cooling. The water has a lot of dissolved calcium , which leads to the problems of scale on pipes. This reduces the cooling efficiency. To minimize the effects of the calcium, the water in the cooling loop was constantly replaced, in order to hold the concentration of the calcium in the cooling water as low as possible, (below the point, where the calcium starts to fall out of suspension and starts to crystallize). This has lead to replacing approximately. 90m3 fresh water per day.

The solution

One Merus® Ring was installed in the cooling loop. Merus® increased the solubility of the calcium in the water. This allowed calcium to build to much higher levels in solution and stay there for much longer, so there is no scale build up.

The Result

After after the installation of Merus®, a lot of calcium was washed out of the system. In the sedimentation tank, a lot of sludge was found. This sludge was easily flushed from the system. The system was set to automatically top itself up when the water conductivity was at a set value. This value was increased slowly in the weeks after installation. The cooling capacity of the system was also monitored.
  • There is no longer any need to replace the water in the cooling loop anymore.
  • Today water top up replacement is 8m3 saving the client approximately 80m3 water per day.

THENAMARIS INC, Shipping Company, Greece

The Problem

sea water treatment ships
In every tanker there is at least one seawater boiler (evaporator), in which the seawater partially evaporates (at low pressure due to low temperature) and the residual brine is returned back into the sea. The produced water vapors are condensed at a cold surface and feed the ship’s fresh water tanks. Inside the heat exchanger of the evaporator a stony layer consisting of salt, lime and other solids contained in the seawater is gradually formed. This layer absorbs an essential part of the thermal energy, which is normally intended for the evaporation of the seawater.

As a result, the evaporator’s performance is reduced daily and the fresh water production becomes insufficient for the ship’s needs. When this point is reached, expensive fresh water has to be purchased at the harbors. The traditional solutions are chemical and mechanical cleaning. Both processes are hard, tough, unhealthy and expensive. It also means that the evaporator has to be stopped for many hours once per one to two months, which is not always convenient.

The Solution

We placed Merus® rings on the pipes which supplies sea water to the boiler and evaporator. The boiler was recently cleaned and the evaporator had not been cleaned lately and its daily fresh water production had already dropped noticeably as it usually did at this time. The flow rate was several m3/h.

The Result

The boiler and the evaporator did not need any cleaning again. Performance on both units increased dramatically and within a short time the evaporator reached its highest limit, according to its specifications. This means that the scale was removed without chemical cleaning.

Aout one month after the installation of the rings the tanker’s engineer reported that the daily fresh water production of the evaporator, instead of dropping gradually, as it always did, had increased from 28 to 31 tons.

…Thats 3 TONS more water produced PER DAY

Merus® rings not only prevent the formation of new scale, but also manages to dissolve residual scale, which cannot be reached with chemicals and scrapers. Chemical and mechanical cleaning can never remove scale build up or rust 100%. It is technically impossible to reach all surface area of the internal system.

City Council, Berlin, Germany

The Problem

In water fountains there are high amounts of water evaporating continuously. This water has to be replaced. Depending on the design of the fountain, there could be an evaporation line around the fountain, and a lot of scale. It is very common, to find in algae in fountains and ornamental pools. Despite the addition of chemicals to the water, the cleaning of the fountain was hard and time consuming. High pressure cleaners and strong chemicals have to be used, in order to get the fountain clean again. Cleaning was very expensive, with a total cost of several 1.000 EUR per year.

The Solution

A Merus® Bio ring was installed to stop chemical usage and to reduce scale build up.

The Result

Depending on the design of the fountain, results can be seen quite quickly. At one area in particular, it was noticeable on a daily basis how much the scale was reducing from the granite stones at the waterfall, where there is a constant flow of water. A lot of biomass from outside (eg pollen) is brought in the water, these accelerate the growth of the algae. The new growth of algae could therefore not be stopped totally, but the algae now only lasts for a few days, turns brown and falls to the bottom of the water. So in general the fountains have become cleaner The effect could be seen best during cleaning. Most of the scale and algae has been flushed away during the draining of the fountain or just with the water hose.
  1. The scale is gone
  2. Algae has decreased significantly
  3. The fountain is cleasner
  4. Cleaning time is halved
  5. Sigificantly less chemical usage