Carbohydrazide as an Oxygen Scavenger: Mechanism, Benefits & Industrial Use
Release time: 2025-10-31
BLIT CHEMICAL Carbohydrazide CAS 497-18-7 oxygen scavenger
In industrial water treatment and boiler systems, oxygen is one of the most damaging impurities. Even trace amounts of dissolved oxygen can cause severe corrosion, pitting, and degradation of metal surfaces. To prevent such damage, chemical oxygen scavengers are used to eliminate oxygen before it causes harm. Among these, Carbohydrazide has emerged as one of the most effective, safe, and environmentally responsible options.
This article explains the mechanism, benefits, applications, and handling of Carbohydrazide as an oxygen scavenger, offering insights for engineers, formulators, and buyers seeking reliable water treatment solutions.
For technical support or supply inquiries, you may contact BLi-T (Hefei) Chemical Co., Ltd. at info@blitchem.com — a professional manufacturer of Carbohydrazide with years of industry experience.
What is Carbohydrazide?
Carbohydrazide (chemical formula CH6N4O, CAS No. 497-18-7) is a white crystalline solid derived from hydrazine and carbonic acid. It is classified as a reducing agent and is primarily used to remove dissolved oxygen from water systems, particularly in boilers and power plants.
Despite its name similarity, Carbohydrazide is not toxic like hydrazine. Instead, it serves as a safer alternative with comparable or even superior performance. When dissolved in water, it reacts rapidly with oxygen to produce harmless nitrogen, water, and carbon dioxide.
Key properties of Carbohydrazide:
- Molecular weight: 90.08
- Melting point: 153–154 °C
- Solubility: Soluble in water and alcohol
- Appearance: White crystalline powder
- Odor: Odorless
- Toxicity: Low (safer substitute for hydrazine)
Why Oxygen Scavengers are Essential in Water Treatment
Oxygen dissolved in water is a major cause of corrosion in industrial systems such as:
- Boilers and heat exchangers
- Condensate and feedwater lines
- Power plant turbines
- Closed cooling systems
Even a few parts per billion (ppb) of oxygen can lead to rust and metal pitting, shortening equipment lifespan and decreasing efficiency. To prevent this, oxygen scavengers chemically react with oxygen, converting it into stable and non-corrosive compounds.
Carbohydrazide offers a reliable solution because it is:
- Fast-reacting, ensuring complete oxygen removal before the water enters the boiler.
- Thermally stable, effective under high-pressure and high-temperature conditions.
- Environmentally safer, decomposing into gaseous byproducts without solid residues.
How Carbohydrazide Works as an Oxygen Scavenger
Reaction Mechanism
Carbohydrazide removes oxygen through a redox reaction, where it donates hydrogen atoms to oxygen molecules, reducing them to water. The overall simplified reaction is:
[2 N_2H_3CO + O_2 → 2 N_2 + 2 H_2O + CO_2]
In this reaction:
- Oxygen (O₂) is reduced to water (H₂O).
- Carbohydrazide is oxidized to nitrogen (N₂) and carbon dioxide (CO₂).
The process is clean and efficient, producing only gases that easily vent out of the system without forming sludge or deposits.
Comparison with Hydrazine
| Feature | Hydrazine | Carbohydrazide |
| Toxicity | Highly toxic, carcinogenic | Low toxicity, safer handling |
| Decomposition products | Ammonia, nitrogen, hydrogen | Nitrogen, CO₂, water |
| Environmental impact | Hazardous | Eco-friendly |
| Storage stability | Moderate | Excellent |
| Handling safety | Requires special precautions | Normal industrial safety sufficient |
This makes Carbohydrazide the preferred replacement for hydrazine in modern boiler operations.
Benefits of Carbohydrazide as an Oxygen Scavenger
High Reactivity and Efficiency:Quickly eliminates oxygen even at low concentrations, ensuring zero oxygen residuals in boiler feedwater.
Thermal Stability:Performs effectively at temperatures up to 300°C, making it ideal for high-pressure steam generation systems.
No Corrosive Residues:Leaves no solid byproducts, keeping boiler tubes and pipelines clean.
Safety and Environmental Compliance:Non-carcinogenic and compliant with modern environmental regulations, replacing hydrazine-based systems.
Versatility:Can be used in a wide range of applications, including power plants, refinery boilers, and chemical process water systems.
Extended Equipment Lifespan:Reduces corrosion and scaling, leading to fewer maintenance shutdowns.
Cost Efficiency:Its long-lasting protective effect lowers chemical consumption and operational costs.
Applications of Carbohydrazide
1. Boiler Feedwater Treatment
Carbohydrazide is primarily used to protect metallic surfaces in boilers and feedwater systems from oxidative corrosion. It reacts with any remaining oxygen that escapes the deaerator, providing a final chemical deoxygenation step.
2. Power Plants
In high-pressure steam systems, Carbohydrazide maintains a reducing environment in the water circuit, preventing corrosion in turbines and heat exchangers.
3. Cooling Systems
Used in closed recirculating cooling systems where oxygen ingress is minimal but must still be controlled to prevent long-term corrosion.
4. Electronics & Semiconductor Water Systems
Its purity and low residue formation make it suitable for use in high-purity water systems required by semiconductor and electronics manufacturing.
5. Reducing Agent in Chemical Synthesis
In chemical processes, Carbohydrazide functions as a mild reducing agent, participating in the synthesis of pharmaceuticals, dyes, and polymer stabilizers.
Dosage and Application Method
| System Type | Recommended Dosage | Injection Method |
| Low-Pressure Boiler | 0.2–0.4 mg/L | Continuous feed into deaerated water |
| Medium/High Pressure Boiler | 0.5–1.0 mg/L | Injection into feedwater line |
| Condensate Return System | 0.1–0.3 mg/L | Dosing pump at condensate tank |
| Closed Cooling System | 0.05–0.1 mg/L | Manual or automatic feed |
It is best added continuously using a metering pump before the economizer or deaerator. Periodic testing ensures oxygen levels remain below 10 ppb.
Safety and Handling Precautions
Although Carbohydrazide is much safer than hydrazine, it should still be handled carefully:
- Avoid inhalation or prolonged skin contact.
- Use gloves and goggles during handling.
- Store in tightly sealed containers, away from moisture and direct sunlight.
- Dispose of waste according to local regulations.
Shelf life: 24 months under dry, ambient conditions.
Since carbazine is a dangerous chemical and its dangerous goods category is 9, UN3077, the packaging we use for international transport complies with international transport conditions.
For safety data sheets (MSDS) and technical guidance, please contact info@blitchem.com.
Environmental and Regulatory Advantages
Carbohydrazide is compliant with most environmental protection guidelines. It meets the safety standards required by modern industries and is considered a green chemical alternative to toxic hydrazine.
Because it decomposes into harmless gases, it poses no risk of water contamination or air pollution, aligning with sustainable water treatment practices worldwide.
Why Choose BLi-T (Hefei) Chemical Co., Ltd.
BLi-T Chemical is one of the reliable manufacturers and exporters of Carbohydrazide in China.We have been manufacturing carbazine for over ten years and supplying it to many factories and distributors.
Our advantages include:
- Consistent high purity (≥99%) product quality and Free hydrazine ≤250 PPM(BLIT Chemical manufactures carbonylhydrazine using virgin hydrazine hydrate, not recycled hydrazine hydrate.)
- Reliable global supply and export support(BLIT Chemical’s carbonylhydrazine has been successfully exported to several countries, including Türkiye, Saudi Arabia, and Russia.)
- Technical assistance for water treatment formulation
- Fast logistics and documentation support (MSDS, COA, TDS)
We serve customers in power generation, chemical processing, and water treatment sectors across more than 10 countries.
For product details or quotations, please contact:info@blitchem.com
FAQs
Q1: What makes Carbohydrazide a safer choice than hydrazine?
A1: Unlike hydrazine, Carbohydrazide is non-carcinogenic, less volatile, and easier to handle, making it a safer choice without compromising oxygen scavenging performance.
Q2: Can Carbohydrazide be used with other treatment chemicals?
A2: Yes, it is compatible with most boiler treatment formulations including pH adjusters, scale inhibitors, and phosphates.
Q3: Is Carbohydrazide suitable for food industry steam systems?
A3: It can be used in systems where indirect steam contact occurs, but compliance with local regulations should always be verified.
Q4: What is the best way to store Carbohydrazide?
A4: Keep in airtight containers, away from heat and moisture, and in a well-ventilated storage area.
Carbohydrazide has become the preferred oxygen scavenger for industrial water treatment due to its high efficiency, low toxicity, and eco-friendly profile. It effectively removes dissolved oxygen, prevents corrosion, and extends equipment lifespan—without the hazards of traditional hydrazine.
For high-purity Carbohydrazide supply, technical consultation, or bulk purchase, reach out to BLi-T (Hefei) Chemical Co., Ltd. at info@blitchem.com.
Our team provides full support, including MSDS, TDS, COA, and custom packaging to meet your specific needs.
