Scale and corrosion in 3 independent cooling systems stopped.
Company: Nuplas Industries, Jebel Ali Freezone Dubai, UAE
About the customer:
Nuplas Industries is a well known company producing packaging material based on polymeres, typically used in the food or pharmaceutical industry. Also there is a line of extruders producing drinking cups. The production was started in 1997 in the Jebel Ali Free zone in Dubai, UAE, and has been constant extended , both in size and quality of production. Today Nuplas Industries is supplying more then 25 countries, with their different lines of products.
The processing of polymere and similar products requires cooling in certain production steps. The customer plant is located in the middle east, where during the summer temperature might reach 40°C and more, so cooling is required for the labour and for some of the machinery. For the cooling in the plant there are 3 independent cooling systems, two chilled water systems and one open cooling system with a cooling tower. All these cooling systems shared one common problem, in all systems corrosion was a big issue and also scaling could be found. Additional in the cooling tower the problem of algae could be very easy seen, as the colour of the water in the cooling tower sump was bright green. Although the corrosion and fouling happened even with chemical treatment of all 3 cooling systems. These fouling problems required regular manual cleaning of the heat exchangers. So there has been regular cleaning every 2 to 3 month of the different machines.
None of the different cooling loops is longer then 200 metres, so only 2 Merus Rings have been installed in each cooling loop. In addition, at the feed line of the city water one more Merus ring was installed. The cleaning of the system took place in two steps. After the installation, the former setup of the water treatment hasn't been changed. After 30 days the half of the water was replaced. It could be found a lot of thicker scale and rust particles in the sump or in the chilled water tank. Seeing this, the chemical additives has been stopped, after another 30 days again half of the water has been replaced.
In the first step of the cleaning process it already could be recognized a lot of material coming out of the system. Also in the cooling tower the algae turned brown and fall down to the bottom of the cooling tower. As there is no high sophisticated machinery installed to monitor the water quality, pipes and heat exchangers has to be opened to be inspected and checked visually.
First the manager of the plant didn't see too much commercial benefits, as the cost of the Merus Rings has been almost as much as the cost of the chemicals used before. This opinion changed after seeing how well Merus performed. Not only all the chemical treatment is stopped, but also the results are far better then they have ever been before. Looking on the fact there is no need of cleaning the equipment anymore, this is nowadays done only during regular shutdown period, the calculation looks totally different. There is no emergency shutdown anymore, so the production time of the plant has increased. Also the energy balance is positive. As there is no fouling in the heat exchangers anymore the produced cold can be transferred at design level into the cooling water. Considering all the improvements done by Merus, the ROI is less then 6 month.