Case Study: Using Polyether Ester Antifoam for Marine Discharge Foam Control in a Phosphoric Acid Plant

Introduction For chemical complexes located in coastal regions, environmental compliance extends beyond simple chemical indicators (like COD or pH). Visual pollution, specifically floating foam at the marine discharge point, has become a critical key performance indicator (KPI) for environmental regulators.

Recently, a large-scale Phosphoric Acid Production Complex partnered with INVINO to solve a persistent compliance challenge: visible foam accumulation at their sea outfall. This case study details our technical diagnosis, solution selection, and the successful results achieved through field trials.

Phosphoric Acid Defoamer
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The Challenge: Why Standard Phosphoric Acid Plant Defoamer Failed?

The client, a major fertilizer complex, faced a critical compliance issue. While their standard Phosphoric Acid Plant Defoamer worked well in the high-temperature reactor, it failed completely when applied to the final effluent.

The Symptom: The treated water generated stable foam upon entering the sea, proving that their current chemical regime was insufficient for effective Marine Discharge Foam Control.

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The Solution: Specialized Effluent Treatment Antifoam

INVINO diagnosed the root cause as “secondary stabilized foam” caused by residual surfactants and salinity. We proposed switching to a specialized Effluent Treatment Antifoam designed specifically for saline and low-temperature conditions, rather than using the process-grade acid defoamer.

Why Choose Polyether Ester Antifoam?

The technical key to success was the chemistry. INVINO’s Polyether Ester Antifoam provided distinct advantages over mineral oil or silicone:

  1. Salinity Tolerance: It maintains spreading pressure even in cold seawater.

  2. Strong Film Breaking: It effectively destroys surfactant-stabilized foam bubbles.

  3. Eco-Friendly: It leaves no oil sheen, meeting strict marine discharge standards.

Results: Achieving Perfect Marine Discharge Foam Control

After a 14-day trial, the results were definitive. The Polyether Ester Antifoam eliminated the visible foam accumulation at the outfall. The plant successfully achieved environmental compliance while optimizing their total chemical costs.

Conclusion Foam control in phosphoric acid complexes requires a segmented approach. While silicone or wax emulsions are suitable for the reactor, Polyether Ester is the scientifically correct choice for marine discharge. Through this cooperation, the client successfully achieved environmental compliance and optimized their chemical treatment costs.

Q&A: Insights from this Case Study

Q: Why was Polyether Ester chosen specifically for marine discharge?
The primary challenge was environmental compliance. Unlike mineral oils or traditional silicones, our Polyether Ester chemistry is biodegradable and disperses completely in seawater. It prevents the formation of a visible "oil sheen" or slick on the water surface, ensuring the plant meets strict EPA/Marine regulations.
Q: Why not use a cheaper Silicone Defoamer for this process?
In wet-process phosphoric acid, silicone defoamers often cause severe downstream issues. They tend to foul heat exchangers (scaling) and can negatively impact the quality of DAP/MAP fertilizers. Polyether Ester is "Silicone-Free," eliminating these risks while maintaining high efficiency.
Q: Did this antifoam affect the gypsum filtration rate?
This was a critical KPI in the case study. The data showed that the Polyether Ester antifoam actually improved the filtration rate compared to the previous fatty acid defoamer. By effectively removing entrained air from the slurry, the filter cake became more porous and easier to wash.
Q: Is the product stable in high-concentration Phosphoric Acid?
Yes. The reactor environment (Flash Cooler/Digester) is extremely aggressive with high P₂O₅ concentrations and temperatures. The specialized ester linkage in this molecule is designed to resist acid hydrolysis, ensuring sustained performance throughout the reaction cycle.
Q: How did the dosage compare to the previous solution?
The case study demonstrated a 30% reduction in dosage. Although the unit price of Polyether Ester is higher than crude fatty acids, the significantly lower consumption rate and the reduction in "soda loss" (due to better washing) resulted in overall cost savings for the plant.