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Water is Nature's most Wonderful, most abundant, useful compound. It is estimated that 2/3 rd of the human body constitutes of Water. It also occupies a unique position in industries. It has a very important use as an engineering in stem generation. Water is also used as a coolant in power and chemical plants. Water is very complex in nature. It contains a lot of impurities in dissolved & suspended form. The calcium & magnesium salts present in the water determines the hardness of water. It is this hardness of water which is of concern for scale problems in industries.
Scale-Ban is a major breakthrough in preventing the formation of scale. Once installed in the system, it requires no maintenance or energy costs resulting in zero production down time and zero equipment deterioration because of hard water scale.
SCALE- BAN TREATMENT
Scale-Ban is an innovative concept in the field of hard water scale problems. It comes in the shape of a pipe and can be easily installed in the present cooling water circuit.
This On-line equipment does not require any energy for operation. It requires no regeneration or maintenance, resulting in zero equipment down time and zero equipment deterioration.
The theory of working of Scale-Ban is very simple. It makes the use of flow and chemical characteristics of water and precipitates out hardness causing salts of very small size as the water flows through Scale-Ban. These salts are suspended in water because of being light in weight and the turbulent flow. Thus , once precipitation of hardness causing salts have taken place, further precipitation because of temperature variation is not possible. The result is a totally scale free system.
PRINCIPLE OF WORKING OF SCALE-BAN
All crystallisation events require, that a thermodynamics driving Force exists. For the case of carbonate scale from hard water this driving force can be expressed as a ratio of the Concentration of Calcium ions and Carbonate ions in the water to their concentration in a water in Equilibrium with scale crystals. This is termed as the Super Saturation Ratio. If its value is less than one, any scaling will tend to dissolve. The parameters that control the super-saturation ratio for CaCO3 are the water composition i.e. hardness, alkalinity, pH, etc., temperature and pressure. The mechanism by which Scale-Ban can alter the super-saturation ratio of the water locally, and which therefor, affect this precipitation are scientifically proven.
- The Scale-Ban alloy adsorbs positive ions, which in the case of hard water are predominantly calcium ions, into the layer of water in contact the Scale-Ban unit. On order to retain an overall neutral charge negative ions such as carbonate, bicarbonate, and hydroxyl, accumulate in the water volume element adjacent to this layer; the bulk of the water remains unaffected by these events.
- The turbulence of the water flowing past the Scale-Ban causes pressure variation in the water. In regions of low pressure i.e. down streams of the turbulence bars and the Scale-Ban itself, carbon dioxide will come out of solution . This performs a dual role locally. The condition artificially stabilizes the growing crystals created by the first mechanism and, in addition, the total system becomes less likely to further precipitate calcium carbonate.
By this surface chemical adsorption effect Scale-Ban creates
an environment of an increase in the super-saturation ratio in the narrow
water volume close to the Scale-Ban surface enhancing the precipitation
of calcium carbonate crystals.
Having precipitated the salts into the core in the right size range
(0.01u - 0.5u) the turbulence in the water physically removes the precipitates
from the surface of the core and washes it downstream. If the flow is
not turbulent, the Scale-Ban will not work. The minimum flow
rate is approximately 5 ft/sec in the pipe or 9ft/sec in the unit itself.
The minimum flow rate for turbulence is that giving a REYNOLDS No. of
2000 minimum.
