Water treatment systems supplier Water Engineering Systems Unlimited (WESU) uses a new water filtration system to keep heat exchangers working efficiently.

WESU uses water treatment engineering and manufacturing company Universal Environmental Technology’s (UET’s) ScaleBio filter technology to eliminate scale corrosion and biolife in water systems and heat exchangers, making them work more effectively. The technology uses a partial electrolysis technique to balance the water, based on its chemical parameters and the engineering parameter of the system.

“The water treatment itself is mainly used to keep heat exchangers efficient and scale-and corrosion-free, which no other chemical treatment can guarantee,” says WESU representative Zwi Wagner.

UET partial electrolysis technology prevents scale, corrosion and biolife in industrial, commercial and mining water systems, and treats supply water, industrial water, sea water, and process water. The systems are manufactured for WESU by UET, the developer of the partial electrolysis water treatment technology.

“The system effects a reduction in maintenance, labour, capital replacement and energy costs, while at the same time being environmentally friendly,” says Wagner.

“The system does not require skilled labour to operate, or maintain, nor does it need any added chemicals. “It can be monitored from any place in the world, ensuring that your water treatment is performing at all times,” says Wagner.

Wagner adds that the treatment has been installed in over a thousand applications worldwide.

“Illovo Sugar has installed two systems for a power plant and Sappi is in the process of commissioning another system,” states Wagner.

De Beers uses the system at its Orapa and Letlhakane mines, in Botswana, on its raw water, process water and plant potable water. Illovo Sugar uses it in its Sezela mill for its power station cooling system.

Internationally, it is used by Coca-Cola in Austin Texas, BMW, Bayer, and Thyssen Krupp Steel, in Germany, for use in cooling systems, and by Ingersoll Rand and BAC, for use in the gasfields of Kazakhstan. Siam Steel, in Thailand, is using it on their steel wire plant, and a village in Israel is using it to treat its main supply water.

“Sasol has successfully com- pleted a pilot run and is in the implementation stage of the technology at its synfuel plant, to prevent scale in its heat exchangers,” states Wagner.

He adds that AngloGold Ashanti’s Noligwa plant is budgeting for it in its capital investment budget for next year to treat its gland water. Many other mines and plants are in various stages of implementing this technology.

ILLOVO SUGAR SELEZI MILL

In January, the ScaleBio filter was commissioned in the Illovo Sugar Selezi sugar mill’s power station in Durban to solve the problems excess scale, iron and sulphur-reducing bacteria that originate in the river water.

The scale had reduced the heat transfer efficiency on the turbine bearings to the extent that some of the pipes had to be renewed, and the bacteria caused excessive corrosion, affecting the maintenance load and resulting in excessive maintenance and equipment replacement costs, says WESU.

The system is monitored by the WESU RS1000, which sends short message service signals in cases of a change in the status of the machines. It also sends a status signal once a day to assure manage- ment that the system is working well.

MAKHTESHIM CHEMICAL WORKS

A UET water treatment process unit was installed in the hot water system at the Makhteshim Chemical Works in Israel, with water on the one side of a heat exchanger, and steam on the other.

The UET-SR-HW process unit was installed to protect a plate heat exchanger from scaling and fouling.

WESU says that previously the heat exchanger would block frequently owing to extensive scale build-up on the heat exchanger’s plates, which resulted in a drop in efficiency.

The factory had to open the plate heat exchanger for cleaning every three weeks. This cleaning procedure is very expensive and time-consuming as the plates have to be cleaned by hand with acid and new gaskets have to be installed and oven-cured, says WESU.

“Since the installation of our UET-SR-HW, the heat exchanger is free of scale and the efficiency is constant and there is no need for cleaning every three weeks,” says Wagner.

SIAM STEEL

Siam Steel, in Thailand, which produces 400 000 t/y of special quality wire rods for the construction industry, has been using the UET partial electrolysis technology in its cooling towers and other applications.

The latest installation was in its mould cooling system where previously distilled water was used and where the contact temperature reached 1 000 �C.

WESU says the installation of the UET system resulted in a saving in water, cutting the blow-down from 36 m3/d when treated by chemicals, to 0,5 m3/d.

Total customer cost of the water treatment was reduced significantly, taking into account a 40% saving in water, increased mould life, reduced maintenance cost, lessened production down time, and capital replacement cost, as no acid treatment is required.

ORAPA DIAMOND MINE PLANT 2

In August 2006, the scale and biolife filter, based on the UET technology, was commissioned in the Botswana Orapa diamond mine to treat the process and gland water and to solve the problems of excess scale in the gland water, corrosion in the process water, as well as scale and biolife in the potable water.

The scale blocks the water pipelines and accelerates the wear of the mechanical seals, shafts and glands of the slurry pumps. The potable water, with a total dissolved solids level of 2 700 ppm, has a large scale potential and requires disinfection, both of which are tackled by the scale and biolife filter, says WESU.

CONTAINERISED WATER FILTRATION SYSTEMS

WESU also delivers some of the water filtration systems in ocean freight containers for ease of use.

“The systems are sometimes delivered, already installed inside containers. “This saves a company building costs and makes connection easier as it only needs to be connected on the outside. The rest is already done,” comments Wagner.

In December 2006, a containerised water filtration system was delivered to Sappi Saiccor, in Durban.

“The most common scale we normally deal with is calcium carbonate in cooling towers, closed and open cooling systems, and hot and cold natural water,” says Wagner.

The system was designed to filter out calcium sulphate in the process liquid. Calcium, in association with sulphate, has a much stronger bond than the normal scale composed of calcium and carbonate, and as such it is much more difficult to remove from the water system.

WESU supplies and maintains water treatment systems that use no chemicals, to prevent scale, corrosion, and biolife. The UET water treatment system, based on partial electrolysis technology, was developed in Israel 15 years ago.