The Complete Guide to Acid Cleaning Copper Coils & Heat Exchangers
What you will learn
💡 Frequently Asked Questions
Find quick answers to common questions about the complete guide to acid cleaning copper coils & heat exchangers.
The Complete Guide to Acid Cleaning Copper Coils & Heat Exchangers
Compare chemical properties and select the right acid for descaling copper coils and heat rolls.
Acid Cleaning Heat Rolls and Copper Coils
Acid cleaning heat rolls and copper coils removes mineral scale, oxidation, and fouling that degrade thermal efficiency. Copper is highly conductive but susceptible to corrosion if exposed to the wrong acid or excessive concentrations. Selecting the correct chemical—whether phosphoric, citric, acetic, or hydrochloric acid—depends on the scale type, system metallurgy, and application environment.
Phosphoric Acid (85% Technical Grade) for Copper
Phosphoric acid 85% is widely used for descaling copper heat exchangers because it dissolves mineral deposits while being less aggressive on base metals than stronger mineral acids.
- CAS Number: 7664-38-2
- Molecular Weight: 98
- Boiling Point: 213°C (415.4°F)
- Melting Point: 42°C (107.6°F)
Citric Acid Monohydrate (USP Food Grade)
Citric acid monohydrate is a weak organic acid ideal for food-grade applications and sensitive copper components. It acts as a chelating agent, binding to metal ions to remove scale without severe corrosive effects.
- CAS Number: 5949-29-1
- Molecular Weight: 210.14
- Boiling Point: 175°C (347°F)
- Flash Point: 385°C (725°F)
Acetic Acid (Glacial Technical)
Glacial acetic acid (100% concentration) is a highly concentrated organic acid used for specialized descaling where water introduction must be controlled before dilution.
- CAS Number: 64-19-7
- Molecular Weight: 60.05
- Boiling Point: 118°C (244.4°F)
- Flash Point: 39°C (102.2°F)
Hydrochloric Acid (31% Technical Grade)
Hydrochloric acid 31% (HCl) is a strong mineral acid that rapidly dissolves severe calcium and magnesium scale. However, it is highly aggressive toward copper and must be used with extreme caution.
- CAS Number: 7647-01-0
- Molecular Weight: 36.46
- Boiling Point: 108°C (226.4°F)
- Melting Point: -74°C (-101.2°F)
General Acid Cleaning Procedures
When performing acid cleaning on heat rolls or copper coils, operators must follow systematic procedures to prevent metal loss.
- System Isolation: Disconnect the heat exchanger from the main process loop.
- Flushing: Flush the system with water to remove loose debris.
- Acid Circulation: Circulate the diluted acid solution. Consult manufacturer instructions for specific dilution ratios and circulation times.
- Neutralization: Thoroughly flush the system with water and a neutralizing agent to halt the acid's reaction with the copper.
| Chemical | CAS Number | Molecular Weight | Boiling Point |
|---|---|---|---|
| Phosphoric Acid 85% | 7664-38-2 | 98 | 213°C |
| Citric Acid Monohydrate | 5949-29-1 | 210.14 | 175°C |
| Acetic Acid Glacial | 64-19-7 | 60.05 | 118°C |
| Hydrochloric Acid 31% | 7647-01-0 | 36.46 | 108°C |
Frequently Asked Questions
What is the best acid for cleaning copper coils?
Phosphoric and citric acids are commonly preferred for copper due to their effectiveness on scale and lower corrosivity compared to strong mineral acids.
How do you perform acid cleaning on heat rolls?
Isolate the system, flush with water, circulate the appropriate acid solution according to manufacturer instructions, and follow with a thorough neutralizing rinse.
Can hydrochloric acid be used on copper heat exchangers?
Yes, but HCl 31% is highly aggressive. It should only be used for severe scaling, typically with inhibitors, and requires strict adherence to SDS and manufacturer guidelines to prevent pitting.
Is citric acid safe for food-grade systems?
Yes, Citric Acid Monohydrate USP Food Grade is frequently used to descale copper coils in food and beverage processing facilities.
What is the boiling point of 85% phosphoric acid?
According to its chemical profile, 85% technical grade phosphoric acid has a boiling point of 213°C or 415.4°F.
Why does glacial acetic acid freeze?
Acetic Acid Glacial Technical has a melting point of 16°C or 60.8°F, causing it to solidify in cool environments.
Ready to source high-quality acids for your facility's maintenance program? Alliance Chemical offers technical and food-grade acids for industrial descaling. Browse our selection of <a href="/products/phosphoric-acid-85-technical-grade">Phosphoric Acid 85%</a>, <a href="/products/citric-acid-monohydrate-usp-food-grade">Citric Acid Monohydrate</a>, <a href="/products/acetic-acid-glacial-technical">Acetic Acid Glacial</a>, and <a href="/products/hydrochloric-acid-31-technical-grade">Hydrochloric Acid 31%</a> to keep your heat exchangers operating at peak efficiency.
Acetic Acid Glacial TechnicalHydrochloric Acid 31% Technical GradePhosphoric Acid 85% - Technical GradeFrequently Asked Questions
What is the best acid for cleaning copper coils?
Phosphoric and citric acids are commonly preferred for copper due to their effectiveness on scale and lower corrosivity compared to strong mineral acids.
How do you perform acid cleaning on heat rolls?
Isolate the system, flush with water, circulate the appropriate acid solution according to manufacturer instructions, and follow with a thorough neutralizing rinse.
Can hydrochloric acid be used on copper heat exchangers?
Yes, but HCl 31% is highly aggressive. It should only be used for severe scaling, typically with inhibitors, and requires strict adherence to SDS and manufacturer guidelines to prevent pitting.
Is citric acid safe for food-grade systems?
Yes, Citric Acid Monohydrate USP Food Grade is frequently used to descale copper coils in food and beverage processing facilities.
What is the boiling point of 85% phosphoric acid?
According to its chemical profile, 85% technical grade phosphoric acid has a boiling point of 213°C or 415.4°F.
Why does glacial acetic acid freeze?
Acetic Acid Glacial Technical has a melting point of 16°C or 60.8°F, causing it to solidify in cool environments.
