What is the amount of HPAA added?

The addition amount of HPAA (Hydrolyzed Polymaleic Anhydride) depends on the application scenario, water quality, and system requirements. Below are general dosage guidelines for common applications:

1. Industrial Cooling Water Systems

Scale Inhibition:

Low-hardness water (Ca²⁺ < 100 mg/L): 2–10 mg/L

Medium/high-hardness water (Ca²⁺ 100–500 mg/L): 10–20 mg/L

High-temperature/high-alkalinity systems: 15–30 mg/L

Corrosion Inhibition (when combined with organic phosphonates like HEDP/ATMP): 5–15 mg/L

2. Boiler Water Treatment

Low-pressure boilers (<1 MPa): 5–15 mg/L

Medium-pressure boilers (1–4 MPa): 10–20 mg/L

High-pressure boilers (>4 MPa): 15–30 mg/L (often combined with phosphate-based treatments)

3. Reverse Osmosis (RO) Systems

General antiscalant dosage: 3–10 mg/L (adjusted based on SDI, LSI, and Ca²⁺/SO₄²⁻ levels)

For high silica (SiO₂) waters: 5–15 mg/L (HPAA helps disperse colloidal silica)

4. Oilfield Water Treatment

Scale control in injection water: 10–30 mg/L

Combination with phosphonates (e.g., ATMP/HEDP): HPAA (5–15 mg/L) + HEDP (5–10 mg/L)

5. Detergents & Cleaning Agents

Laundry detergents: 0.1–0.5% (enhances anti-redeposition)

Industrial cleaners: 0.5–2% (improves scale removal)

Key Factors Affecting Dosage

Water Hardness – Higher Ca²⁺/Mg²⁺ requires more HPAA.

pH – Works best in pH 7–9; adjust dosage if outside this range.

Temperature – Stable up to 100°C, but higher temps may need increased dosing.

System Contaminants – High Fe³⁺/SiO₂ may require extra dispersant action.

Comparison with Other Scale Inhibitors

Scale Inhibitor Typical Dosage (mg/L) Best For

HPAA 5–30 High hardness, high temp

PAA 10–50 General dispersancy

HEDP 5–20 Calcium carbonate inhibition

PASP 5–25 Eco-friendly systems

Recommendations for Optimal Use

✅ For cooling water: Start with 10 mg/L HPAA + 5 mg/L HEDP for dual scale/corrosion control.

✅ For RO systems: Use 3–8 mg/L HPAA with pH adjustment (5–7) for best results.

✅ Monitor residuals: Test total organic phosphorous (TOP) to ensure proper dosage.