A DEHA inhibitor is used in boiler systems to prevent corrosion. It acts as an oxygen scavenger, effectively removing oxygen from the water. This helps to protect the metal surfaces inside the boiler from rust and decay. The inhibitor also helps maintain system efficiency by keeping surfaces clean and free from buildup. DEHA is used in water treatment chemicals to ensure longer equipment life and reduced maintenance costs.
What is DEHA (N,N – Diethylhydroxylamine) in Water Treatment?
Dissolved oxygen in boiler water causes corrosion and metal surface damage, leading to inefficiency, equipment failure, and downtime. N,N-Diethylhydroxylamine (DEHA) is a volatile amine used to remove oxygen in boiler systems. Hydrazine was once widely used for its oxygen scavenging and surface protection properties. When found toxic in the early 1970s, DEHA became the preferred choice due to its lower toxicity and beneficial properties.
Why Use DEHA in Boiler Systems?
DEHA is effective due to its ability to neutralize free radicals, which can cause oxidative damage in boiler systems. It acts as an oxygen scavenger throughout the entire boiler, maintaining consistent protection against oxidation.
DEHA is suitable for various systems, including pressure boilers, due to its efficient oxygen-scavenging properties. It is the most effective for high and medium-pressure boilers but it is less efficient in low-pressure boilers due to low reaction rates. Its volatile nature allows it to spread through water and steam, offering complete protection for boiler systems.
DEHA also helps protect low-carbon steel by converting red rust to black magnetite throughout the boiler system, preventing further corrosion.
In boiler systems, DEHA breaks down into neutralising amines, diethylamine and ethylmethylamine, which increase the pH of condensate, reducing the need for extra treatment.
In wet lay-up scenarios, DEHA prevents corrosion and controls oxygen levels. It is commonly used with morpholine during boiler storage to maintain pH and prevent corrosion.
Although it is usually encountered in smaller systems, DEHA’s versatility makes it adaptable to diverse industrial applications.
Benefits of DEHA Inhibitor
Antioxidant Properties
DEHA inhibitor acts as an antioxidant in boilers. It prevents oxidation, reducing rust and decay. This leads to a longer lifespan for equipment. Regular use ensures optimal performance by maintaining clean internal surfaces and decreasing maintenance needs.
Stabilisation of Polymers
The DEHA inhibitor helps stabilise polymers within the boiler system. This ensures efficient operation and reduces the risk of equipment failure. Keeping polymers stable leads to improved safety and reliability in boiler operations.
Corrosion Inhibitor
DEHA is a powerful corrosion inhibitor for boilers. It reduces rust and scale formation. This ensures efficient boiler operation and longer equipment life. Using DEHA reduces maintenance costs and limits equipment downtime. It provides complete corrosion protection for metal surfaces.
Versatile Solvent
The DEHA inhibitor acts as a versatile solvent. It helps in dissolving impurities and contaminants in boiler systems. This property aids in maintaining system cleanliness and efficiency. Regular use of DEHA as a solvent reduces the need for extensive cleaning.
Environmental Benefits
DEHA is eco-friendly and less toxic than hydrazine. It decomposes into water and nitrogen, leaving no hazardous byproducts. This makes it safe for the environment. Using DEHA contributes to greener industrial processes by reducing harmful emissions.
Improved Product Shelf Life
Using DEHA in boilers improves product shelf life. It helps maintain water quality and system efficiency. This protection ensures equipment longevity and reduces downtime. Adopting DEHA leads to lower maintenance costs and sustainable operations for industries.
Chemical Intermediary
DEHA inhibitors serve as chemical intermediaries. They assist in reactions needed to create other compounds. This role makes them essential for producing desired chemicals in industrial processes. DEHA’s ability to facilitate these reactions ensures their practical application in manufacturing.
Energy Efficiency
DEHA improves energy efficiency in boiler systems. It minimises fuel consumption and cuts down on energy costs. The improved efficiency helps industries save money. Using DEHA contributes to sustainable operations and better utilisation of resources.
Application & Dosage Information
Steam Boilers
Feed CB22 / AT-2344 continuously to the deaerator storage, condensate, or directly to the boiler. Choose the feed point based on the issue to be fixed. Accepta technical support will advise on the concentration needed in the feedwater, as it varies with operating pressure and installation. Normally, 20 ml/m3 of feed water per mg/L of dissolved oxygen is used. Adjust the dosage to maintain 0.1-0.25 ppm of DEHA in the feed or boiler water.
High Pressure Hot Water Systems
DEHA is often employed in high pressure settings where rapid oxygen removal is critical. Dose CB22 / AT-2344 initially at 200ml/m3. Maintain a DEHA residual of 5-10ppm. Always conduct a ‘Control Of Substances Hazardous to Health’ (COSHH) assessment before use.
Safety, Storage & Handling
Safety, Storage & Handling
Use DEHA inhibitors with caution. Here are some steps to take:
- Ensure a proper safety assessment is conducted before handling
- Store the chemical in a cool, dry place away from direct sunlight
- Keep containers tightly sealed to prevent leaks or contamination
- Avoid skin and eye contact; use protective gear when handling
- Follow all safety guidelines and use appropriate ventilation in work areas
- Dispose of any waste as per local regulations.
Ensuring Quality Through DEHA Testing by Comfort Services Group
Comfort Services Group specialises in DEHA testing to maintain water treatment systems. Our tests measure DEHA levels in boiler systems accurately. Regular testing ensures the system operates efficiently and safely. We check DEHA concentration to prevent issues and prolong equipment life. Our process is reliable and trusted, making sure that systems are running at optimal conditions. We help clients meet their maintenance goals effectively and economically.
FAQs
Is DEHA an amine?
N,N-Diethylhydroxylamine (DEHA) is a volatile amine used to remove oxygen in boiler systems. Hydrazine was previously popular for treating boilers due to its ability to remove oxygen and protect surfaces.
What concentration of DEHA is recommended for effective oxygen scavenging?
Industrial applications needing oxygen scavenging and passivation with minimal solids in boiler water include pulp and paper utilities. For low to moderate pressure industrial boiler systems, an initial DEHA dosage of 300-500 ppb is recommended.
How effective is DEHA compared to traditional oxygen scavengers like hydrazine?
DEHA is an effective hydrazine replacement. It requires 40% more DEHA than hydrazine for oxygen scavenging. DEHA offers advantages like low toxicity and volatility over hydrazine and also reacts with ferrous metals to form a passivized film of magnetite throughout the entire boiler system due to steam carryover.
Are there specific testing methods for measuring DEHA levels in boiler water?
There is no official method to test for DEHA in boiler feedwater or condensate. However, a modified ferrous iron colorimetric test is often used for low levels of DEHA. In the PDTS method, ferric iron in the sample is reduced to ferrous iron by DEHA. The ferrous iron then reacts with PDTS to form a pink-purple complex. This colour change indicates the concentration of DEHA.
What safety precautions should be taken when using DEHA in boiler water treatment?
When using DEHA for boiler water treatment, it is important to ensure safety and follow specific guidelines. DEHA is a chemical that can be hazardous if not handled properly.
- Wear protective gear such as gloves and goggles.
- Ensure proper ventilation in work areas.
- Keep DEHA containers tightly sealed.
- Store DEHA in cool and dry conditions.
- Avoid contact with skin and eyes.
- Dispose of DEHA waste according to local regulations.
- Conduct regular safety assessments.
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