Chemical injection quills allow direct delivery of chemicals into fluid systems. Their design protects pipelines, ensures safe flow, and improves mixing. Each chemical must match the quill’s material to prevent corrosion and failure.
This article lists five common chemicals that are compatible with most chemical injection quills. It explains why these chemicals are used and how they interact with system components.
1. Sodium Hypochlorite (NaOCl)
Sodium hypochlorite is a strong oxidizer. It is used in water treatment to kill bacteria and viruses. It also removes odors and helps control algae.
Injection quills made from PVC, CPVC, or Hastelloy are usually safe for sodium hypochlorite. These materials resist the oxidizing effect of the chemical. The check valve must also use compatible seals, such as Viton or EPDM.
Use Case
Water plants use sodium hypochlorite to disinfect drinking water. The quill delivers it directly into the flow for fast reaction.
2. Sulfuric Acid (H₂SO₄)
Sulfuric acid is a strong acid. It lowers pH and removes minerals from fluid systems. It is common in cooling towers, power plants, and chemical industries.
Quills made from PTFE-lined stainless steel or Hastelloy can handle sulfuric acid. The design must avoid metal parts exposed to the acid. This prevents damage and extends system life.
Use Case
Cooling systems use sulfuric acid to reduce scaling. The acid enters the pipe through the quill and mixes with the circulating water.
3. Sodium Hydroxide (NaOH)
Sodium hydroxide is a strong base. It raises pH and neutralizes acids. It is used in wastewater treatment, pulp processing, and food cleaning systems.
Sodium hydroxide reacts with some metals. Stainless steel 316 and certain plastics like PVDF or PTFE can resist the base. Choosing the correct material prevents wear and cracking.
Use Case
In wastewater systems, sodium hydroxide helps balance the pH. The injection quill allows direct dosing into the stream without damaging the pipe.
4. Corrosion Inhibitors (Amine-based)
Corrosion inhibitors protect metal pipes from rust and erosion. Amine-based inhibitors form a protective film inside the pipe. These chemicals are common in oil and gas systems and boiler water treatment.
Stainless steel, Hastelloy, and certain plastics can tolerate these inhibitors. The quill must inject the chemical near the pipe center for full mixing. This ensures the film forms evenly.
Use Case
Gas pipelines use injection quills to deliver corrosion inhibitors. The chemical forms a layer on the inner pipe surface, reducing wear over time.
5. Antiscalants (Phosphonate-based)
Antiscalants stop mineral build-up. Phosphonate-based antiscalants work by changing how minerals crystallize. This keeps pipes and equipment clean and efficient.
Most antiscalants are compatible with stainless steel, PVC, and CPVC. The quill should have a non-stick surface to reduce residue and buildup at the nozzle.
Use Case
Reverse osmosis systems use antiscalants to keep membranes clean. The chemical enters through a quill to mix with the incoming water.
Material Matching Is Key
Chemical compatibility depends on matching the chemical to the material of the injection quill. Some materials work with many fluids, while others are specific.
| Material | Works With |
|---|---|
| PVC / CPVC | Sodium hypochlorite, phosphonates |
| Stainless Steel | Sodium hydroxide, corrosion inhibitors |
| Hastelloy | Sulfuric acid, oxidizers, harsh chemicals |
| PTFE / PVDF | Strong acids, strong bases, sensitive fluids |
Safety and Mixing Considerations
Each chemical must enter the center of the flow. This ensures quick and even mixing. If a chemical touches the pipe wall, it may corrode the metal or form deposits. Injection quills prevent this by placing the nozzle in the right position.
The quill’s check valve stops fluid from flowing backward. This protects the chemical tank and pump from contamination.
Conclusion
Chemical injection quills safely deliver chemicals into flowing systems. Their design protects pipelines and improves chemical use. Five common compatible chemicals are:
- Sodium hypochlorite
- Sulfuric acid
- Sodium hydroxide
- Amine-based corrosion inhibitors
- Phosphonate-based antiscalants
Each chemical requires a specific material match. This prevents corrosion and ensures long-term performance. The injection quill, when selected and used correctly, helps control treatment processes with safety and accuracy.