Top 7 Applications of Ammonia Synthesis Catalysts

Ammonia synthesis catalysts play a central role in converting purified nitrogen and hydrogen into ammonia through the Haber–Bosch process. Although the catalyst performs the same fundamental function in each plant, its operating environment can vary considerably according to feedstock, production capacity, synthesis-loop design and downstream application.

Modern ammonia producers require catalysts that provide high activity, stable long-term operation and reliable performance under the selected temperature and pressure conditions.

This article examines seven major industries and production scenarios in which ammonia synthesis catalysts are used.

What Is an Ammonia Synthesis Catalyst?

An ammonia synthesis catalyst accelerates the reversible reaction between nitrogen and hydrogen:$$N_2 + 3H_2 \rightleftharpoons 2NH_3$$

Without a catalyst, the reaction rate would be too slow for economical industrial production. Inside the ammonia converter, the catalyst helps nitrogen and hydrogen react efficiently under elevated temperature and pressure.

Industrial catalyst performance can be affected by several factors, including:

• Operating temperature and pressure
• Hydrogen-to-nitrogen ratio
• Synthesis-gas purity
• Catalyst particle size
• Converter and catalyst-bed design
• Resistance to heat and catalyst poisons
• Catalyst reduction and start-up procedures

Honrel supplies an iron-cobalt dual-active ammonia synthesis catalyst designed for high catalytic activity under low-temperature and low-pressure conditions. Available oxidised and pre-reduced grades support different plant start-up and operating requirements.

1. Nitrogen Fertiliser Production

Nitrogen fertiliser production is the largest industrial application for ammonia synthesis catalysts. Ammonia is the essential nitrogen source used to manufacture products such as:

• Urea
• Ammonium nitrate
• Ammonium sulphate
• Ammonium phosphate fertilisers
• Compound NPK fertilisers

In an integrated fertiliser plant, hydrogen and nitrogen are first purified and compressed before entering the ammonia synthesis loop. The catalyst enables ammonia formation inside the converter, after which the ammonia is separated and sent to downstream fertiliser units.

Stable catalyst activity is especially important in this industry because fertiliser plants commonly operate continuously and at large scale. A decline in conversion efficiency can increase circulation requirements, energy consumption and production costs.

For fertiliser manufacturers, catalyst selection should therefore consider long-term stability, mechanical strength, reduction behaviour and compatibility with the existing converter.

2. Natural Gas-Based Ammonia Plants

Natural gas is one of the most widely used feedstocks for conventional ammonia production. In these plants, natural gas is desulphurised and converted into hydrogen-rich synthesis gas through steam methane reforming. Nitrogen is generally introduced through the secondary reforming stage.

After carbon monoxide, carbon dioxide, water and other impurities are removed, the purified hydrogen and nitrogen enter the ammonia synthesis loop.

Natural gas-based plants usually benefit from relatively mature process technology and consistent feed conditions. However, catalyst performance remains crucial to:

• Maintain the required ammonia concentration at the converter outlet
• Support steady synthesis-loop operation
• Reduce unnecessary recycle loads
• Improve production efficiency
• Extend the operating period between catalyst replacements

Sulphur compounds, oxygen-containing impurities and other contaminants must be carefully controlled before the synthesis gas reaches the catalyst. Even a high-performance catalyst depends on effective upstream purification.

3. Coal-Based Ammonia Production

Coal-based ammonia production is important in regions with abundant coal resources and limited access to competitively priced natural gas.

In this production route, coal is gasified to create raw synthesis gas. The gas then passes through several purification and conditioning stages, which may include:

• Particulate removal
• Sulphur removal
• Water-gas shift conversion
• Carbon dioxide removal
• Methanation or final gas purification
• Hydrogen-to-nitrogen ratio adjustment

The treated gas is then compressed and sent to the ammonia synthesis converter.

Compared with natural gas-based production, coal gasification may create a more complex impurity profile. Efficient desulphurisation and final gas purification are therefore necessary to protect the ammonia catalyst.

Catalysts used in coal-based ammonia plants should provide dependable activity, thermal stability and resistance to short-term variations in operating conditions. Proper catalyst loading and uniform gas distribution are also important for achieving consistent performance across the catalyst bed.

4. Green Ammonia Production

Green ammonia is produced using hydrogen generated from water electrolysis powered by renewable energy. Nitrogen is normally obtained from an air-separation system, and the two gases are purified and fed into an ammonia synthesis unit.

Unlike traditional plants, green ammonia facilities may receive electricity from variable sources such as wind and solar power. Depending on the plant design, this can create changes in hydrogen availability and overall production load.

Ammonia synthesis catalysts used in these projects may need to support:

• Lower-temperature operation
• Lower-pressure synthesis concepts
• Flexible production rates
• Frequent load changes
• Efficient start-up and shutdown strategies
• Smaller or modular plant configurations

The catalyst alone does not determine whether a plant can operate dynamically. Converter design, heat management, hydrogen storage and synthesis-loop control are also critical. Nevertheless, high low-temperature activity can give process designers more flexibility when developing energy-efficient green ammonia systems.

Green ammonia can be used in fertiliser production, chemical manufacturing, energy storage and other emerging low-carbon applications.

5. Nitric Acid and Industrial Explosives Industry

Ammonia synthesis catalysts support the production of ammonia used as the main feedstock for nitric acid and ammonium nitrate. These materials are widely consumed by the mining, quarrying, construction and industrial explosives industries.

In nitric acid plants, ammonia is oxidised to produce nitric acid. The resulting nitric acid can then react with additional ammonia to manufacture ammonium nitrate. Industrial ammonium nitrate is used to produce products such as:

• Ammonium nitrate fuel oil (ANFO)
• Emulsion explosives
• Water-gel explosives
• Mining-grade ammonium nitrate
• Blasting agents for quarrying
• Explosives used in infrastructure construction

Mining and explosives manufacturers depend on a stable ammonia supply because interruptions in upstream ammonia production can affect nitric acid and ammonium nitrate output.

The ammonia synthesis catalyst does not participate directly in nitric acid or explosives production. Its role is to maintain efficient ammonia production at the beginning of the manufacturing chain. Stable catalyst activity, low pressure drop and long operating life help ensure a dependable supply of ammonia for downstream plants.

This application is particularly relevant to integrated chemical facilities that combine ammonia synthesis, nitric acid production and ammonium nitrate manufacturing at one industrial site.

6. Synthetic Fibres and Engineering Plastics Industry

Ammonia is an important upstream raw material in the production of several chemicals used by the synthetic fibre, textile and engineering plastics industries.

Major ammonia-derived chemical routes include:

• Caprolactam production: Caprolactam is the primary monomer used to manufacture nylon 6 fibres, engineering plastics and industrial yarns.
• Acrylonitrile production: Ammonia reacts with propylene and oxygen to produce acrylonitrile, which is used in acrylic fibres, ABS plastics and nitrile rubber.
• Hydrogen cyanide production: Ammonia is used in industrial processes that produce hydrogen cyanide, an intermediate for acrylic materials, resins and specialised chemicals.
• Hexamethylenediamine production: Ammonia-related chemical processes support the production chain for nylon 6,6 and other polyamide materials.

The resulting materials are used in:

• Automotive components
• Electrical and electronic housings
• Industrial textiles
• Carpets and clothing fibres
• Packaging materials
• Mechanical components
• Nitrile rubber products
• Consumer appliances

In these production chains, the ammonia synthesis catalyst is used upstream to produce the ammonia required by downstream chemical units.

7. Ammonia for Industrial Chemicals, Metallurgy and Electronics

Not all ammonia is used to manufacture fertiliser. Industrial ammonia also serves as a raw material or process gas in several non-fertiliser sectors.

Chemical manufacturing

Ammonia is used to produce nitric acid, amines, nitriles, refrigerants, explosives, polymers and numerous other chemical intermediates.

Metallurgical processing

Ammonia-derived atmospheres can be used in heat treatment, nitriding, sintering and other controlled-atmosphere processes. In these cases, ammonia production supports the upstream supply of the required industrial gas.

Electronics and high-purity applications

High-purity ammonia is used in semiconductor, LED and specialised electronic-material production. These applications require additional purification after synthesis to achieve the necessary impurity specifications.

The ammonia synthesis catalyst is used during the initial production of ammonia; it does not by itself determine final electronic-grade purity. Downstream purification, storage and contamination control remain essential.

This distinction is also important for ammonia cracking. Ammonia synthesis catalysts produce ammonia from nitrogen and hydrogen, whereas ammonia cracking catalysts are selected to decompose ammonia back into hydrogen and nitrogen. The two processes should not be treated as the same application when selecting a catalyst.

How to Select an Ammonia Synthesis Catalyst

The appropriate catalyst cannot be chosen solely by comparing product names. Buyers should provide detailed operating information so that the supplier can assess compatibility with the plant.

1. Plant capacity
   Specify the required daily or annual ammonia output.
2. Converter design
   Provide the converter type, bed configuration and available catalyst volume.
3. Operating conditions
   State the inlet temperature, maximum operating temperature and synthesis pressure.
4. Synthesis-gas composition
   Include the hydrogen-to-nitrogen ratio and expected concentrations of residual impurities.
5. Existing catalyst information
   Share the current catalyst grade, particle size, loading quantity and operating results.
6. Pressure-drop requirements
   Particle size must balance catalytic surface area with gas-flow and pressure-drop requirements.
7. Start-up strategy
   Determine whether an oxidised or pre-reduced catalyst is more suitable for the project.
8. Expected operating cycle
   Discuss production continuity, turnaround schedules and target catalyst service life.

Buyers can explore Honrel’s broader range of industrial catalysts or review the company’s complete chemical raw material product portfolio.

Why Catalyst Quality Matters

The ammonia converter is one of the most important sections of an ammonia plant. Catalyst quality can directly influence conversion performance, start-up time and long-term operating stability.

A suitable industrial catalyst should offer:

• High activity within the specified operating range
• Good thermal stability
• Reliable resistance to catalyst poisons
• Consistent particle size and bulk density
• Adequate mechanical strength
• Stable catalyst-bed performance
• Predictable reduction behaviour
• Batch-to-batch quality consistency

Honrel’s HY201 series uses iron and cobalt as dual active components. The product range includes grades developed for low-temperature and low-pressure activity, wider operating-temperature requirements and pre-reduced applications. Final grade selection should be confirmed against actual plant data.

Conclusión

Ammonia synthesis catalysts are primarily associated with fertiliser production, but their industrial relevance extends across multiple feedstock routes and production models. They are used in natural gas-based and coal-based ammonia plants, green ammonia projects, integrated chemical complexes, modular production units and facilities supplying ammonia to metallurgy, electronics and other chemical industries.

Across all seven scenarios, successful performance depends on matching the catalyst to the synthesis-gas quality, converter design and operating conditions. Upstream purification, correct loading, controlled reduction and sound plant operation are just as important as the catalyst itself.

Honrel produces and supplies chemical raw materials and industrial catalyst products for customers in international markets. To discuss catalyst grades, particle sizes, technical requirements or sample availability, Contacta con Honrel with your plant and operating information.

item	unit	HA201-2	HA201-2-H
Apariencia		Black,with metallic luster and magnetic properties,irregular solid particles	Silver-gray,with metallicluster and magnetic properties,irregular solid particles
Size	mm	1.5～3.0、2.2～3.3、3.3～4.7、4.7～6.7、6.7～9.4、9.4～13.0
Bulk density	Kg/l	2.9～3.2	2.2～2.5
Particle density	Kg/l	3.8～4.2	2.8～3.2
Skeleton density	Kg/l	7.2～7.6	7.2～7.6
Porosity	%	~45	~45
Form factor	φs	Large-particle catalyst: 0.40～0.50Small particle catalyst: 0.50～0.60

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Preguntas frecuentes

What is the main application of an ammonia synthesis catalyst?

Its main application is catalysing the reaction between nitrogen and hydrogen during industrial ammonia production. Most ammonia is used in nitrogen fertilisers, while the remainder supports chemical, metallurgical, energy and electronics-related industries.

Which catalyst is commonly used for ammonia synthesis?

Promoted iron-based catalysts are widely used in industrial ammonia plants. Some formulations incorporate additional active components or promoters to improve low-temperature activity, thermal stability or resistance to impurities.

Can the same catalyst be used in natural gas- and coal-based plants?

Potentially, but suitability must be evaluated against each plant’s synthesis-gas purity, converter design, pressure, temperature and expected impurity profile. The feedstock route alone is not sufficient for selecting a catalyst.

Can ammonia synthesis catalysts be used in green ammonia plants?

Yes. Green ammonia still requires nitrogen and hydrogen to react in an ammonia synthesis loop. Catalyst selection should account for the plant’s pressure, temperature, production scale and expected load variation.

Does an ammonia synthesis catalyst also crack ammonia?

Ammonia synthesis and ammonia cracking are reverse processes, but industrial catalysts are selected and engineered for their specific operating duties. A dedicated ammonia cracking catalyst should be used when the objective is to decompose ammonia into hydrogen and nitrogen.