Ammonia-Based FGD: Turning SO₂ Removal Into a Resource Recovery Opportunity

Focus Keywords: ammonia-based FGD, ammonia desulfurization, ammonia FGD system, flue gas desulfurization, ammonium sulfate fertilizer

Meta Description: Discover how ammonia-based FGD removes SO₂ from industrial flue gas while producing ammonium sulfate as a useful by-product. MirShine provides customized ammonia desulfurization solutions for industrial applications.

Why Ammonia-Based Desulfurization Is Attracting Industrial Attention

Sulfur dioxide (SO₂) is one of the major pollutants generated by combustion and industrial processes using sulfur-containing fuels or raw materials.

Power plants, steel mills, chemical plants, non-ferrous metal smelters, and other heavy industries have traditionally relied on different desulfurization technologies to control SO₂ emissions.

Among these technologies, ammonia-based flue gas desulfurization has a particularly interesting feature: the desulfurization reagent can become part of a useful product rather than simply becoming a waste stream.

In an ammonia-based FGD system, ammonia reacts with sulfur dioxide and produces ammonium sulfate.

Ammonium sulfate is widely used as a nitrogen and sulfur fertilizer. This creates the possibility of combining pollution control with resource recovery.

For industrial companies that have access to ammonia and have a market or internal use for ammonium sulfate, ammonia-based FGD can be an attractive alternative to conventional limestone-based processes.

MirShine Environmental Group has developed experience in ammonia-based flue gas treatment and provides customized solutions according to different industrial flue gas conditions.

How Does Ammonia-Based FGD Work?

The basic principle is based on the reaction between ammonia and sulfur dioxide.

When SO₂-containing flue gas contacts an ammonia-containing absorption solution, sulfur dioxide is absorbed and reacts with ammonia.

The resulting ammonium salts can be further processed into ammonium sulfate.

The simplified overall process can be represented as:

SO₂ + NH₃ + H₂O → ammonium sulfite/bisulfite

The absorbed sulfur compounds can then be oxidized to form ammonium sulfate.

The exact process configuration depends on the selected technology and operating conditions.

Unlike processes that use limestone to produce gypsum, ammonia-based FGD uses ammonia as the absorbent and creates an ammonium sulfate product.

What Makes Ammonia-Based FGD Different?

The most important difference is the value of the final product.

In a conventional limestone-gypsum FGD system, sulfur dioxide is removed by limestone slurry and converted into calcium sulfite or calcium sulfate, ultimately producing gypsum under suitable process conditions.

In ammonia-based FGD, the sulfur component is combined with ammonia and can be recovered as ammonium sulfate.

This means the system can be considered from two perspectives:

Pollution control

The plant removes SO₂ from flue gas and reduces atmospheric emissions.

Resource recovery

The sulfur is converted into a fertilizer product rather than being treated solely as a waste.

This combination is one of the reasons ammonia-based FGD is particularly interesting for industries that already have an ammonia supply chain.

Where Can Ammonia-Based FGD Be Used?

Power Generation

Coal-fired power plants and other combustion facilities can use ammonia-based FGD to control SO₂ emissions.

The suitability of the technology depends on fuel sulfur content, flue gas volume, emission requirements, ammonia availability, and the intended use of the ammonium sulfate product.

Steel Industry

Steelmaking and related processes can generate sulfur-containing flue gas.

An ammonia-based system can be considered when the plant is looking for both emission reduction and potential sulfur resource recovery.

Chemical Industry

Chemical plants may already have ammonia infrastructure, making ammonia-based FGD particularly interesting.

Existing ammonia storage and distribution facilities can potentially be integrated with the FGD system, subject to detailed engineering and safety assessment.

Smelting and Metallurgical Processes

Non-ferrous metallurgy can generate SO₂-rich gases.

The gas composition and concentration may differ considerably from conventional boilers, so process design must be based on actual operating data.

The Role of Ammonia Quality and Supply

Because ammonia is directly used in the desulfurization process, its availability is an important factor in project planning.

The project team needs to consider:

• Ammonia concentration

• Supply method

• Storage capacity

• Transportation

• Consumption rate

• Safety requirements

The economics of ammonia-based FGD are closely connected to ammonia price and the value of the ammonium sulfate product.

Therefore, a technical evaluation should normally be combined with an economic assessment.

Ammonium Sulfate as a By-Product

One of the major advantages of ammonia-based FGD is the potential production of ammonium sulfate.

The product contains both nitrogen and sulfur and can be used as a fertilizer when it meets the applicable product quality requirements.

This creates a different economic model from traditional waste treatment.

Instead of paying only for reagent consumption and waste disposal, the plant may be able to recover a useful material from the sulfur contained in its flue gas.

The actual product quality depends on process control, raw gas composition, oxidation conditions, crystallization or concentration processes, and downstream handling.

Engineering Considerations for Ammonia FGD

Although the basic chemistry is straightforward, industrial ammonia FGD requires careful system design.

Gas-Liquid Contact

Efficient contact between flue gas and absorption liquid is essential.

The absorber must provide sufficient contact area and residence time while controlling pressure drop and energy consumption.

Ammonia Utilization

Excess ammonia should be minimized.

Poor control may increase ammonia consumption and create ammonia-related operating problems.

Oxidation

The oxidation stage affects the conversion of absorbed sulfur compounds into ammonium sulfate.

Stable oxidation conditions are therefore important when the plant intends to recover a marketable product.

Product Handling

The ammonium sulfate solution or crystals need to be handled according to the selected process.

Depending on the design, downstream equipment may include concentration, crystallization, separation, drying, and storage systems.

Ammonia FGD Compared With Limestone FGD

Both technologies can provide effective SO₂ removal, but their process economics and product streams are different.

Limestone FGD uses limestone as the main reagent and commonly produces gypsum.

Ammonia FGD uses ammonia and can produce ammonium sulfate.

The appropriate choice depends on:

• Reagent price

• Reagent availability

• Product value

• Waste disposal requirements

• Plant location

• Flue gas composition

• Existing infrastructure

There is no universal answer for every project.

MirShine's Ammonia Desulfurization Solutions

MirShine Environmental Group focuses on industrial flue gas treatment and ammonia-based desulfurization technology.

Our approach is based on the actual conditions of each plant.

The design can consider the complete process, including flue gas characteristics, ammonia supply, absorber operation, oxidation, product recovery, and integration with existing environmental equipment.

MirShine also has experience in other flue gas treatment technologies, allowing ammonia-based FGD to be considered as part of a wider environmental protection system.

For customers requiring multiple pollutant control systems, integrated solutions can combine desulfurization, denitrification, dust removal, and related processes.

Conclusion

Ammonia-based FGD offers more than SO₂ removal.

By converting sulfur dioxide into ammonium sulfate, the process creates an opportunity to combine environmental protection with resource utilization.

For plants with reliable ammonia availability and suitable demand for ammonium sulfate, this technology can provide both environmental and economic advantages.

MirShine develops customized ammonia-based desulfurization systems for industrial customers, with the process design adapted to actual flue gas conditions and project objectives.

Frequently Asked Questions

What is ammonia-based FGD?

Ammonia-based FGD is a flue gas desulfurization process that uses ammonia to absorb and react with SO₂, producing ammonium salts that can be further converted into ammonium sulfate.

What is the main product of ammonia FGD?

The sulfur-containing product is commonly ammonium sulfate, which can be used as a fertilizer when it meets the required quality specifications.

Is ammonia FGD suitable for power plants?

Yes. It can be considered for power plants and other combustion facilities, subject to flue gas conditions, ammonia availability, emission requirements, and project economics.

What is the difference between ammonia FGD and limestone FGD?

Ammonia FGD uses ammonia and can produce ammonium sulfate, while limestone FGD uses limestone and commonly produces gypsum.

Does ammonia FGD require ammonia storage?

An industrial system normally requires an appropriate ammonia supply and storage arrangement. The exact configuration depends on the selected ammonia source and local safety requirements.

Can ammonia FGD produce fertilizer?

Yes. Under suitable process conditions, ammonium sulfate can be recovered and processed as a fertilizer product.

What affects ammonia consumption?

SO₂ concentration, flue gas flow, required removal efficiency, ammonia utilization, process conditions, and system control all affect ammonia consumption.

Can MirShine provide a complete ammonia FGD system?

MirShine can provide customized engineering and equipment solutions for ammonia-based flue gas desulfurization projects, including integration with other pollution control systems.