Since the beginning of time, hard water has been a problem for humans, whether it's making it tough to wash our clothing and cars, or leaving deposits on our kettles and hot water heaters. Typically, calcium and magnesium compounds have precipitated out of water to form hardness scale, e.g., calcium carbonate, magnesium silicate.
This hard deposit can cause chaos by shortening system lifespan and elevating energy, maintenance, and operating expenses. It develops in HVAC cooling systems and process water systems.
How does scale affect water treatment?
Contrary to popular belief, calcium-carbonate hardness is retrogradely soluble. This implies that calcium carbonate becomes less soluble at increasing water temperatures. This property causes scale to frequently accumulate, on the cooling water system's hottest surfaces, which are typically the locations where heat transfers occur.
The system's ability to transport heat is diminished by this extremely insulating coating. In addition to taking up space inside the pipes, scale can affect the system's flow rate and efficiency. In addition to having to work harder to transport energy through this scale, the corrosion inhibitors that have been applied to the system are no longer able to adhere, to the system's metallurgy, which could cause under-deposit corrosion and system damage.
Treatment for scales in water treatment
The amount and likelihood of scale deposition will depend on specific water quality criteria. High amounts of calcium, magnesium, alkalinity, and pH all contribute to an increased risk of scale formation. Pretreatment and chemical additives are two often used strategies for reducing scale formation.
1- Pretreatment
In order to soften the water before it enters the system, water softeners are frequently employed in pretreatment. The softeners have resin beads that are imperceptibly coated in sodium ions. The calcium and magnesium ions are drawn to and allowed to adhere to these beads, by the charged sites on them, whereas the sodium ions are expelled.
The water softener enters a regeneration phase when all the sodium has been extracted, and the beads are coated in hardness ions, releasing the calcium and magnesium that have been trapped and resupplying the beads, with fresh sodium ions.
2- Chemical
It is another strategy used to achieve chemical scale control's goal. The main objective of chemical scale management is to prevent hardness, from building up on the surfaces of cooling water system.
Various methods are combined to achieve this, including:
Threshold Inhibitors: These substances chemically boost the number of scale ions that can be kept in solution.
The amount of hardness the system water can hold is significantly increased, by low concentrations of threshold inhibitors like phosphonates. The systems that concentrate hardness are the ones where threshold inhibitors work best, i.e., cycled up cooling towers. These systems can reach greater concentration cycles while accumulating less scale, when a threshold inhibitor is present.
These inhibitors may wear out if they keep the hardness in solution for an excessive amount of time. In order to make place for new inhibitors to be put into the system to safeguard it, blowdown helps remove the worn-out threshold inhibitors and the concentrated hardness ions, they are retaining.
Changing the growth of crystals: Polymers alter the hardness scale shape, thus making it less stable and more likely to disintegrate. To prevent scale from forming on surfaces, crystal growth modification polymers can also be added to cooling system water.
This is achieved by altering the scale formation's shape, which makes it harder for deposits to form on the system surfaces. Consider the scale molecules to be the bricks of a wall. The crystal growth modifier may cause the molecules' brick-like rectangular form, to convert to a circular one. In order to prevent the hardness from forming on heat transfer surfaces, these polymers are frequently used in cooling towers and boiler systems
Dispersants: These are substances that alter the forces to attract small particles. Dispersants prevent the scale molecules from adhering to one another and generating deposits on the system surfaces, in a way that is similar to how crystal growth modification polymers function, but they do it through a different process.
In other words, molecules with the same charge will resist one another. Dispersants bind to the molecules of the scale, creating a uniform charge all around them. Due to this, molecules resist one another rather than joining forces, and depositing on heat transfer surfaces.
Conclusion
Any efficient cooling water treatment scheme must include the control of scale deposition. While, chemical addition can enhance the capacity for hardness and diminish its adhering characteristics, ion exchange softeners can remove hardness from the water. This allows for higher concentration cycles with less deposition.
In order to keep these systems working longer and more efficiently while lowering operating and maintenance expenses, scale deposition control techniques must be used.
Scale build-ups may eventually lead to continuously increasing fuel and maintenance expenses. The professionals at Netsol Water can assist you in identifying possibilities to increase the lifespan, effectiveness, and dependability of your water systems.
Netsol Water is Greater Noida-based leading water & wastewater treatment plant manufacturer. We are industry's most demanding company based on client review and work quality. We are known as best commercial RO plant manufacturers, industrial RO plant manufacturer, sewage treatment plant manufacturer, Water Softener Plant Manufacturers and effluent treatment plant manufacturers. Apart from this 24x7 customer support is our USP. Call on +91-9650608473, or write us at enquiry@netsolwater.com for any support, inquiry or product-purchase related query.