Breakthrough in Air Pollution Control: How MirShine’s “Ammonia Injection in Acidic Medium” Technology Eliminates Ammonia Slip and Aerosols

The urban clusters along the northern slope of the Tianshan Mountains in Xinjiang occupy only 4.1% of the region’s land area, yet account for nearly half of total coal consumption, emitting over 50% of sulfur dioxide (SO₂) and about one-third of nitrogen oxides (NOₓ) and particulate matter.

Characterized by a heavy industrial structure and coal-dependent energy mix, combined with mountain-enclosed terrain and winter temperature inversions, pollutant dispersion is extremely limited. In winter, the atmospheric environmental capacity is only one-eighth of that in summer, placing enormous pressure on air quality management.

Under China’s “dual-carbon” strategy and increasingly stringent environmental regulations, industrial enterprises in Xinjiang are facing unprecedented challenges in emission control.

The Core Bottleneck: Ammonia Slip and Aerosol Formation

At the end of 2025, the Changji Ecological Environment Bureau, together with the Chinese Research Academy of Environmental Sciences, conducted special monitoring of ammonia slip at key coal-fired power plants.

While the region promotes the “One Enterprise, One Strategy” approach, a fundamental issue remains:
the inherent limitations of conventional ammonia-based flue gas desulfurization technology.

Traditional ammonia-based desulfurization can convert SO₂ into ammonium sulfate fertilizer, but it is often accompanied by two major problems:

• Ammonia Slip: Free ammonia volatilizes from the circulating liquid and escapes with flue gas
• Aerosols: Gaseous ammonia reacts with acidic oxides to form ultrafine ammonium salt particles that are difficult to capture with conventional dust removal systems

An even more subtle issue is condensable particulate matter (CPM). Escaped ammonia reacts with sulfuric and nitric acids to form ammonium sulfate and ammonium nitrate—key contributors to PM2.5. Monitoring data from Changji show that ammonium ions account for up to 21.6% of PM2.5 composition.

Beyond secondary pollution, ammonia slip can also generate ammonium bisulfate, a highly corrosive substance that damages surrounding equipment.

Root Cause of the Problem in Conventional Processes

In traditional ammonia-based systems, ammonia reacts directly with SO₂ to form unstable intermediates such as ammonium sulfite and ammonium bisulfite.

At high temperatures, these compounds easily decompose, releasing gaseous ammonia and SO₂ again—directly causing ammonia slip and aerosol formation.

At the same time:

• Crystallization inside the absorption tower causes continuous increases in circulating liquid density
• Ammonium sulfate becomes difficult to extract efficiently
• Fertilizer accumulates inside the tower, gradually worsening crystallization efficiency
• Ultimately, system instability and shutdown risks arise

These three challenges—ammonia slip, aerosol formation, and poor crystallization efficiency—have long constrained the industry.

MirShine’s Innovation: “Ammonia Injection in Acidic Medium”

Zhang Bo, Chairman of MirShine Environmental, proposed a fundamentally new approach:

Instead of allowing ammonia to directly capture SO₂, the process first uses water to absorb SO₂, forming a sulfite solution. Ammonia is then introduced into the liquid phase to neutralize the solution and directly generate ammonium sulfate.

This innovation ensures that:

• The entire reaction occurs within the liquid phase
• High-temperature flue gas SO₂ never directly contacts ammonia or ammonium sulfite
• Thermal decomposition is fundamentally avoided

As a result, ammonia slip and aerosol formation are eliminated at the source.

Supporting Technology: External Crystallization System

MirShine further enhances system stability with an external crystallization circulation process:

• Crystallization is carried out outside the absorption tower
• Circulating liquid inside the tower remains stable and controllable
• Liquid density no longer continuously increases
• Ammonium sulfate can be efficiently extracted

This provides a solid foundation for long-term stable operation.

Extensive laboratory analysis confirms that:

• The circulating liquid primarily consists of ammonium sulfate solution
• Only trace amounts of ammonium sulfite are present
• Unstable intermediates such as ammonium bisulfite and ammonium bisulfate are virtually eliminated

  Outstanding Environmental Performance

  The emission performance of MirShine’s system is highly competitive:

  • Aerosols, ammonia slip, and CPM are controlled at ultra-low levels (near-zero, in the order of hundredths of mg)
  • Ammonia slip concentration is maintained below 2 mg/Nm³, significantly outperforming the standard requirement of <3 mg/Nm³ specified in Technical Specification for Ammonia-Based Flue Gas Desulfurization (HJ2001-2018)

  In February 2025, MirShine was granted a national patent titled:
  “A Method for Significantly Reducing Ammonia Slip in Ammonia-Based Desulfurization and Its Application,” further strengthening its technological leadership.

  From Pollution Control to Circular Economy Value

  Chairman Zhang Bo also highlights a broader issue:
  Conventional calcium-based desulfurization reduces pollution but generates significant CO₂ emissions, creating a paradox of “pollution control with increased carbon output.”

  MirShine addresses this challenge through a dual approach of ecological recycling and low-carbon economy, converting SO₂ into valuable ammonium sulfate fertilizer and realizing both pollution control and resource recovery.

  A Practical Path for Xinjiang’s Industrial Transformation

  For industrial enterprises in Xinjiang, controlling ammonia slip and aerosols is not only about compliance—it is essential for improving overall regional air quality.

  As air pollution control in the northern Tianshan region enters a critical stage and “One Enterprise, One Strategy” is fully implemented, MirShine’s “ammonia injection in acidic medium” technology provides a practical and scalable solution:

  • Effectively resolves ammonia slip, aerosol, and CPM emissions
  • Transforms environmental investment into economic returns
  • Converts industrial waste gas from an environmental burden into a valuable resource

  As Zhang Bo emphasizes, the ultimate solution to environmental challenges lies in turning waste into value through circular economy principles.