Understanding Antiscalants and Their Uses

In process industries dealing with water, such as desalination, power generation & food processing, scaling on the equipment is always an issue. Scale is a deposit in some forms of hard, chalky substance formed because of mineral deposits and these cause a decrease in operational efficiency, increases maintenance cost and shortens the operational life of equipment. This is where antiscalants come into play.   

What Are Antiscalants? 

Antiscalants are unique chemical additives that are used to guard water systems against the formation of scale. Calcium carbonate, calcium sulfate and silica are some of the minerals that cause scaling if not prevented as they hinder water circulation in membranes, pipes… Antiscalants are applied directly into the water reprocessing process. This helps hinder the formation of crystalline structures, hence making systems to operate as they should. 

How Do Antiscalants Work? 

Antiscalants are used to prevent scaling because they can affect the precipitation of scale-forming minerals. 

 Here's how: 

• Threshold Inhibition: Supersaturation of scaling ions such as calcium, magnesium, and silica are made possible, but the ions cannot form solids. 
• Crystal Modification: Antiscalants prevent the scale-forming from sticking to the surfaces or increasing in size through altering the component make-up of the possible formation of scale deposits. 
• Dispersion: Selective dispersants can also eliminate already formed scale crystal and inhibit formation of particles into larger particles. 

These mechanisms make sure that in the best-case scale will never be realized at all; in the worst case, its occurrence will occur less frequently and/or will be less severe. 

 Common Types of Antiscalants 

1. Phosphonates: These are used widely because of their efficiency in preventing calcium carbonate and calcium sulfate scale.
2. Polymers: Polymeric antiscalants may prevent several kinds of mineral scales such as silica, barium sulfate and iron.
3. Organic Acid Blends: They are prominently applied in water with high total dissolved solids and are most efficient in the suspension of solids. 

 Uses of Antiscalants 

1. Desalination Plants: In SWRO systems, antiscalants play an important role in stopping scale formation on membranes and hence, making the seawater desalination process effective and the membranes have a longer life. 
2. Power Generation: In power utilities where water is used extensively for cooling and numerous other processes, antiscalants are critical in suppressing scale deposition on boilers or in cooling towers which would slow energy throughput and increase maintenance time. 
3. Industrial Water Treatment: Some of the processes that use antiscalants include food processing, pharmaceutical industries, chemical industries that rely on water treatment systems like heat exchangers to be protected from scale.
4. Municipal Water Treatment: Antiscalants enable the municipal water treatment plants to be more efficient in terms of flow and quality since the pipes together with filtration membranes do not get blocked by mineral deposits, hence a steady supply of clean water.
5. Cooling Towers: In large constructions and industrial applications, cooling towers use antiscalants to prevent scaling, which improves efficiency and prevents damage. 

Pros of employing Antiscalants 

• Improved Efficiency: Antiscalants are beneficial to water treatment systems as they help reduce scale formation avoiding build-up on the system. 

• Cost Savings: The use of antiscalants daily makes it possible to avoid raw material cleanings, maintenance, and replacement of most used equipment. 

• Extended Equipment Lifespan: Antiscalants therefore reduce the level of fouling and erosion. 

• Reduced Downtime: Reducing the formation of scales enables organizations to reduce system shut-down, which in turn improves system performance. 

Conclusion 

Antiscalants are critical components in virtually all water treatment applications which aim at keeping industrial equipment from being scaled up. In desalination and power generation, particulate and scale control is accomplished effectively by antiscalants to enhance water treatment infrastructure, minimize cost of formation and maintenance, and improve efficiency of the systems in use in municipal water systems. In the sectors where the water treatment is crucial, the necessity of the antiscalants becomes apparent, as completely useful.