Non-volatile Oxygen Scavenger for Boiler Water

Non-volatile Oxygen Scavenger for Boiler Water

BOILER WATER OXYGEN SCAVENGER D410

1. PRODUCT DEFINITION AND CHEMICAL IDENTITY

Food Contact Steam Approval: D410 is composed solely of non-volatile raw materials. It does not undergo chemical carryover into the vapour phase. The substances in its content consist of raw materials listed in FDA § 173.310 and permitted as additives for boilers producing steam that comes into contact with food. Therefore, it can be used safely in food processes, sterilization, and systems requiring high-purity steam.

2. TYPICAL PHYSICAL AND CHEMICAL PROPERTIES

3. FUNCTIONAL PROPERTIES AND MECHANISM OF ACTION

• Chemical Oxygen Scavenging:

  • Mechanism: Sulfite, the active component of D410, reacts rapidly and quantitatively with dissolved oxygen (O₂) present in the feedwater and boiler water, converting it to sulfate (SO₄²⁻). This reaction occurs very quickly, especially in the presence of a catalyst (pre-added to the product).
    2 Na₂SO₃ + O₂ → 2 Na₂SO₄

  • Result: Dissolved oxygen in the water is completely eliminated, preventing oxygen pitting corrosion on all water-contacted surfaces of the boiler.

• Phase Distribution (Non-Volatile Property):

  • All components constituting D410 are non-volatile. That is, they remain in the boiler water and do not enter the vapour phase.

  • Result: The steam produced remains chemically pure. This property makes the product ideal for food-contact steam applications, pure steam generators, and sterilization systems. It does not provide protection to the condensate line.

• Suitability for Food Contact Steam:

  • The formulation of D410 consists of raw materials listed in FDA § 173.310 (Boiler Water Additives) regulation, permitted for use in boilers whose steam will come into contact with food.

  • Result: Can be used legally in food processing plants, the dairy industry, slaughterhouses, and food packaging sterilization.

4. SECTORAL APPLICATIONS AND USAGE AREAS

5. EXAMPLE RECIPE / DOSAGE RECOMMENDATION

• Initial (Shock) Dose: 200 – 400 ppm (mg/L) based on boiler water volume to rapidly eliminate existing dissolved oxygen and condition the system.

• Maintenance (Continuous) Dose: 20 – 80 ppm (mg/L) continuously, depending on the feedwater flow rate and dissolved oxygen content. As a general rule, dosing of 8-10 ppm sulfite (active substance) is recommended for every 1 ppm O₂ in the feedwater. This amount should be adjusted according to the active substance percentage of the product.

• Dosage Point: For best results, the product should be injected continuously via a dosing pump into the feedwater tank or the feedwater line after the deaerator. The dosing point should be located to provide sufficient contact time for the oxygen scavenger to react before entering the boiler.

Control Parameters: The adequacy of the dosage is checked by the sulfite (SO₃) excess measured regularly in the boiler water. Typically, a sulfite residual of 20-40 ppm is targeted in the boiler water. The feedwater oxygen level should also be monitored.

6. ADVANTAGES

• Suitable for Food Contact Steam (FDA § 173.310): Its formulation is legally suitable for use in boilers whose steam may come into direct contact with food. Ideal for food safety and quality control.

• High-Purity Steam Production: No volatile chemical carryover into the vapour phase. The steam produced is chemically pure; suitable for pure steam generators and sterile processes.

• Fast and Effective Oxygen Removal: Its reaction with dissolved oxygen is extremely rapid, especially in catalyzed formulations.

• Cost-Effectiveness: Generally has a lower unit cost compared to volatile (organic) oxygen scavengers.

• Ease of Use and Control: Its liquid form is suitable for precise feeding with a dosing pump. Its performance can be easily monitored with simple and widely available sulfite test kits.

• Odourless: Unlike amine-based products, it does not have a pungent odour; provides working comfort.

7. DISADVANTAGES AND LIMITATIONS

• Does Not Provide Condensate Protection: As it is non-volatile, it is only effective in the boiler water and feedwater line. It does not provide any protection against CO₂ corrosion occurring in the steam and condensate line. A separate neutralizing or filming amine may need to be dosed for condensate protection.

• Increase in Dissolved Solids: Sulfate is formed as a result of sulfite oxidation. This increases the total dissolved solids (TDS) level in the boiler water. Consequently, the blowdown rate may need to be increased to meet TDS limits.

• Pressure Limitation: In boilers above 40 bar, it is not recommended for use as sulfite can thermally decompose and form corrosive gases such as SO₂ (sulfur dioxide).

• No Steam Space Protection: Cannot provide protection against oxygen corrosion in the boiler steam space where steam does not condense.

8. ALTERNATIVES AND COMPARISON

9. SAFETY AND STORAGE

• GHS Classification (For a typical formulation):

  • Signal Word: Warning (or unclassified).

  • Hazard Statements: H319 (Causes serious eye irritation). Some formulations may have additional warnings. Refer to the product SDS for precise information.

• Personal Protective Equipment (PPE): Use of safety goggles and chemical-resistant gloves (e.g., nitrile, neoprene) is recommended when handling the product.

• Storage: Store in a cool (preferably 5 – 40 °C), dry, and well-ventilated area, in its original, closed packaging. Keep away from strong acids and oxidizers. Contact with acidic substances can release toxic sulfur dioxide (SO₂) gas. Protect from freezing; frozen product will thaw at room temperature and can be used after homogenization.

• Environmental Precautions: Prevent large quantities from directly entering the aquatic environment or drains. At high concentrations, sulfite can deplete oxygen levels in the aquatic environment.

10. FREQUENTLY ASKED QUESTIONS

Q1: Can I safely use D410 in my food factory?
Yes. D410 contains no volatile components that can carry over into the vapour phase and consists of raw materials listed in FDA § 173.310. This means that if the steam it produces comes into direct contact with food, it does not pose a food safety risk. It is specifically formulated for food-contact steam applications.

Q2: What is the fundamental difference between D410 and D401?
The most important difference is that D410 is non-volatile. D410 works only in the boiler water and ensures your steam remains pure, making it ideal for food and sterile applications. D401, on the other hand, is volatile; it also protects steam and condensate lines but is not suitable for food contact steam.

Q3: Why should I monitor the sulfite residual when using D410?
The sulfite residual is the best indicator that you are dosing the correct amount of product. If the residual is zero, it means there is still unremoved oxygen in your water and you need to increase the dosage. If the residual is very high, you are overdosing and unnecessarily increasing the boiler TDS.

Q4: Why doesn't D410 protect my condensate line?
Because D410 is non-volatile, it cannot leave the boiler with the steam. Its protection is physically limited to the boiler water and feedwater line. If you are experiencing corrosion problems in your condensate line, you may need to add a separate food-compatible neutralizing amine to the system via a separate dosing pump.

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