Nitric Acid Production Process: From Science to Industrial Development

Nitric acid is an essential chemical compound in modern industry, widely used in the manufacture of fertilizers, explosives, chemicals and metal treatments. Its production requires a highly controlled process that combines technological innovation and strict safety standards. In this note, we will explore the fundamental stages of the nitric acid production process, highlighting its importance to the industry and its contribution to global development.

1. Raw Materials: Ammonia and Air

The nitric acid production process begins with two essential raw materials:

Ammonia (NH₃): Derived from the Haber-Bosch process, it is the main source of nitrogen in the process.
Air: Provides the oxygen necessary for the oxidation of ammonia.

Both raw materials undergo purification processes to ensure their quality and eliminate contaminants that may affect the efficiency of the process.

2. Oxidation of Ammonia

The first stage of the process, known as catalytic oxidation, converts ammonia into nitric oxide (NO). This step occurs in a reactor where:

Ammonia and air are mixed: In a specific proportion to avoid unwanted side reactions.
The mixture is passed through a catalyst: Usually a platinum-ruthenium mesh that facilitates the chemical reaction.
Chemical reaction: 4NH ₃ +5O₂→4NO+6H₂O

This step is performed at temperatures of 850–950 °C and high pressure (4–10 atm). The nitric oxide generated is the key precursor to nitric acid.

3. Oxidation of Nitric Oxide

The nitric oxide produced is further oxidized in the presence of oxygen to form nitrogen dioxide (NO₂): 2NO+O₂→2NO₂

This step is performed at lower temperatures, around 150-200 °C, to maximize the conversion of nitric oxide to nitrogen dioxide.

4. Absorption and Formation of Nitric Acid

The nitrogen dioxide generated is dissolved in water in an absorption tower to form nitric acid:

3NO₂+H₂O→2HNO ₃ +NO

At this stage:

Absorption tower: Specialized equipment guarantees efficient contact between gas and water.
Recirculation: Some of the unabsorbed nitric oxide is recirculated to improve process efficiency.

The nitric acid produced has a typical concentration of 55-65%, although it can be further concentrated by distillation.

5. Concentration (Optional)

For specific applications, nitric acid can be concentrated to levels above 98%. This step involves removing water by distillation or using concentrated sulfuric acid as a dehydrating agent.

6. Emissions Control

The nitric acid production process generates waste gases, mainly nitrogen oxides (NOₓ), which must be treated to minimize their environmental impact. Common technologies for emission control include:

Selective catalytic reduction (SCR) systems: They transform nitrogen oxides into molecular nitrogen and water.
Absorption in alkaline solutions: Neutralizes acid gases.

These practices ensure that the process complies with the most stringent environmental regulations.

7. Storage and Distribution

The finished nitric acid is stored in specialized tanks made of corrosion-resistant materials such as stainless steel or nickel alloys. The tanks are equipped with safety systems to prevent leaks and control pressure.

From storage, nitric acid is distributed to various industries in tank trucks, containers or barrels according to customer needs.

Applications of Nitric Acid

Nitric acid is a key compound in numerous industries, including:

Fertilizer manufacturing: Such as ammonium nitrate, widely used in agriculture.
Production of explosives: TNT and nitroglycerin.
Metal treatment: Pickling and passivation.
Chemical industry: Synthesis of intermediate products such as nitro compounds and polyurethanes.

Commitment to Sustainability

The modern nitric acid industry is committed to sustainable practices to minimize its environmental impact and improve process efficiency:

Energy optimization: Use of advanced technologies to reduce energy consumption.
Emissions reduction: Rigorous control of NOₓ through capture and neutralization systems.
Waste management: Reuse of by-products and recovery of waste heat.

These initiatives reflect the industry's commitment to sustainable development and compliance with environmental regulations.

Conclusion

The nitric acid production process is an example of how science and chemical engineering transform raw materials into an essential product for modern industry. Each stage, from ammonia oxidation to emissions control, is designed to ensure a high-quality, safe and sustainable product.

At Acciomate Engineering & Projects , we offer engineering and project services that optimize each stage of this process, helping companies in the chemical sector to improve their competitiveness, efficiency and sustainability.