What is Polyacrylate
Polyacrylate is a synthetic polymer used in cooling tower water treatment as a dispersant and scale inhibitor. It’s one of the key components in modern cooling water treatment formulations, especially where phosphate, zinc, or phosphonate programs are used.
What Is Polyacrylate?
- A polymer made from acrylic acid monomers
- Comes in various molecular weights, typically from a few thousand to over a million Daltons
- Often used as sodium polyacrylate in liquid form
How Polyacrylate Works:
- Scale Inhibition
- Prevents precipitation and crystal growth of scale-forming salts like:
- Calcium carbonate (CaCO₃)
- Calcium sulfate (CaSO₄) Barium sulfate (BaSO₄)
- Mechanism:
- Threshold inhibition: Keeps ions soluble at higher concentrations
- Crystal distortion: Alters the shape of scale crystals, making them less adherent
- Dispersant Action
- Keeps silt, iron oxides, biofilm fragments, and corrosion byproducts suspended
- Prevents these from settling and forming under-deposit corrosion sites
- Makes blowdown and filtration more effective
- Stabilizes Other Treatment Chemicals
- Helps keep zinc, phosphate, and phosphonates in solution
- Reduces precipitation of these additives in hard or high-TDS water
Why Use Polyacrylate in Cooling Towers?
Benefit | Description |
Non-phosphorus | Ideal for discharge compliance |
Stable over pH 6–9 | Compatible with most tower conditions |
Works at high temp | Doesn’t degrade easily |
Compatible with biocides | Won’t interfere with oxidizers or biocides |
Typical Dosage:
- 5–20 ppm active polymer, depending on:
- Cycles of concentration
- Calcium/alkalinity levels
- Water reuse or contaminant load
Application Examples:
High cycle towers with scaling risk Zero or low phosphate programs
Towers running on reuse/reclaim water Systems prone to iron fouling or particulate loading