What is the addition concentration of HEDP•Na4 Granule?

The addition concentration of HEDP•Na₄ (Hydroxyethylidene Diphosphonic Acid Tetrasodium Salt) granule is not a single fixed value; it depends entirely on the specific application, water quality, and system parameters.

However, I can provide you with the standard recommended dosage ranges for its most common applications.

First, a Critical Pre-Step: Understanding Concentration
HEDP•Na₄ granule is typically a high-purity solid with a concentration of 90% or higher. When calculating dosage, you are always basing it on the active component (the pure HEDP•Na₄).

• Formula for Required Product Weight:
  Required Product (kg) = (System Volume (m³) × Target Dosage (ppm) ) / (1000 × Product Purity (%))

  • Example: To achieve a 5 ppm active concentration in a 100 m³ system with a 90% pure product:
    (100 m³ × 5 ppm) / (1000 × 0.90) ≈ 0.56 kg of granule product.

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Recommended Dosage Ranges by Application

Here are the typical dosage ranges for HEDP•Na₄ granule, based on active component:

1. Industrial Circulating Cooling Water Systems

This is the most common use. The dosage is influenced by water hardness (Ca²⁺, Mg²⁺ ions) and alkalinity.

• Low Hardness & Low Alkalinity Water:

  • Dosage: 5 – 15 ppm (as active component)

• Medium Hardness & Alkalinity Water (Most Common):

  • Dosage: 10 – 20 ppm (as active component)

• High Hardness, High Alkalinity, High Scaling Tendency:

  • Dosage: 20 – 30 ppm (as active component)

  • Note: In severe cases, it is often used in combination with polymers like PAPE or AA/AMPS for enhanced scale inhibition.

2. Reverse Osmosis (RO) Water Systems

In RO systems, the dosage is critical to prevent membrane scaling and is based on the feed water flow rate.

• Dosage: 2 – 5 ppm (as active component, relative to feed water flow)

• Crucial Note: The exact dosage MUST be determined by using RO projection software (like Genesys, WAVE, or similar) that analyzes a complete water quality report. Overdosing can lead to fouling.

3. Textile & Printing/Dyeing Industries

Used as a stabilizer for hydrogen peroxide (H₂O₂) during bleaching.

• Dosage: 0.5 – 1.5 g/L of bleaching bath (as product).

4. Oil Field Industry

Used in water flooding operations to prevent scale in the formation and well equipment.

• Dosage: 10 – 50 ppm (as active component, in the injection water). The dose is highly dependent on specific formation water chemistry.

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How to Determine the Exact Concentration for Your System

You cannot rely on a generic number. To find the optimal, cost-effective dosage:

1. Water Quality Analysis: This is the most important step. You need a full analysis of the water, including:

   • Calcium Hardness (as CaCO₃)

   • Total Alkalinity (as CaCO₃)

   • pH, Conductivity

   • Concentrations of Mg²⁺, Ba²⁺, Sr²⁺, SiO₂, etc.

2. Software Modeling: For cooling water, use programs like Betz Pilot, Nalco TRASAR, or similar. For RO, use dedicated projection software. These tools calculate the scaling potential and recommend a minimum effective dose.

3. Dynamic Scale Loop Test (DSL): This is the gold standard, especially for critical applications like oil fields. It physically simulates your system’s conditions to find the precise threshold inhibitor concentration.

4. Consult the Supplier: Always refer to the Technical Data Sheet (TDS) provided by your HEDP•Na₄ granule supplier. They will give a recommended starting range based on their specific product’s purity and performance data.

Summary Table

In summary: While a common starting point is 10-20 ppm for cooling water, the correct addition concentration of HEDP•Na₄ granule must be determined by analyzing your specific water chemistry and system conditions. Always start with a dose in the recommended range and adjust based on performance monitoring.