Ammonia escape is a hidden threat in industrial emission control. Excess NH3 that escapes from SCR or SNCR systems can lead to environmental pollution, equipment corrosion, and operational inefficiencies. If not properly managed, it can negatively impact both industrial processes and regulatory compliance.
Ammonia escape causes environmental pollution, equipment damage, and reduced NOx removal efficiency. Effective control strategies include optimizing SCR systems, using high-efficiency catalysts, and continuously monitoring ammonia emissions with advanced gas analyzers.
Understanding ammonia escape is crucial for industries relying on NOx reduction technologies. While selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) systems are designed to minimize nitrogen oxide emissions, improper control can result in excessive ammonia escaping into the atmosphere. Let’s explore its effects and the best ways to manage it.
What Is Ammonia Escape?
Ammonia escape refers to the unreacted NH3 that is released into the exhaust gas stream during NOx reduction processes. This occurs when ammonia, injected into a Selective Catalytic Reduction (SCR) or Selective Non-Catalytic Reduction (SNCR) system, does not fully react with nitrogen oxides (NOx) and instead exits through the flue gas.
Ammonia escape is primarily caused by:
1. Excessive Ammonia Injection – If too much NH3 is introduced into the system relative to the NOx concentration, the surplus ammonia will not have enough NOx to react with and will escape.
2. Catalyst Degradation – Over time, SCR catalysts lose efficiency due to fouling, poisoning, or thermal aging, reducing their ability to facilitate the NOx-ammonia reaction and leading to higher ammonia escape levels.
3. Inadequate Mixing and Reaction Time – Poor distribution of ammonia in the flue gas or insufficient residence time in the reactor can result in incomplete reactions, causing unreacted ammonia to pass through the system.
4. Incorrect Operating Temperature – Both SCR and SNCR systems require specific temperature ranges for optimal reactions. If temperatures are too low, ammonia does not react efficiently, increasing ammonia escape levels.
Since ammonia escape can lead to environmental pollution, equipment corrosion, and regulatory compliance issues, industries must implement precise monitoring and control strategies to minimize its occurrence.
What Are the Main Effects of Ammonia Escape?
Ammonia escape has serious environmental, operational, and economic consequences. When excess NH3 is released into the exhaust gas stream, it not only reduces the efficiency of NOx control systems but also leads to harmful byproducts that affect air quality and industrial equipment. Below are the major impacts of ammonia escape:
1. Environmental Pollution
Ammonia escape contributes to the formation of fine particulate matter (PM2.5) and secondary pollutants, which degrade air quality and pose health risks.
• Unreacted ammonia can react with sulfur dioxide (SO₂) and nitrogen oxides (NOx) in the atmosphere to form ammonium sulfate and ammonium nitrate, which are major components of PM2.5 pollution.
• PM2.5 is a known health hazard that can cause respiratory diseases, cardiovascular issues, and reduced lung function when inhaled over long periods. NH3 emissions can also contribute to acid rain formation and nitrogen deposition, which negatively impact soil and water ecosystems.
2. Equipment Corrosion and Maintenance Issues
Ammonia escape can lead to the formation of ammonium salts, which corrode industrial equipment and increase maintenance costs.
• In power plants and industrial boilers, ammonia reacts with SO₂ and sulfur trioxide (SO₃) in the flue gas, forming sticky deposits of ammonium bisulfate (ABS) on heat exchangers and air preheaters.
• These deposits reduce heat transfer efficiency, leading to increased energy consumption and equipment wear over time.
• Corrosion caused by ammonia-related compounds can result in frequent shutdowns, expensive repairs, and shorter equipment lifespans in SCR systems and downstream components.
3. Reduced NOx Removal Efficiency
High ammonia escape levels indicate inefficient NOx control, leading to non-compliance with environmental regulations and increased operational costs.
• If ammonia is escaping, it means that the system is either injecting too much reagent or the catalyst is not performing effectively, reducing overall NOx removal efficiency.
• Inefficient NOx control can cause regulatory violations, leading to fines, operational restrictions, and increased scrutiny from environmental agencies.
• Industries may need to increase NH3 injection to compensate for catalyst inefficiencies. further escalating reagent costs and ammonia escape risks.
The impacts of ammonia escape extend beyond simple inefficiencies in NOx reduction. Ammonia escape causes pollution, equipment damage, and compliance issues, making it a key concern for industries. Using advanced monitoring, optimizing injection, and maintaining catalysts help reduce its impact.
How to Control Ammonia Escape Effectively?
1. Optimizing Ammonia Injection – Proper control of the ammonia-to-NOx ratio ensures complete reaction and minimizes excess ammonia.
2. Upgrading Catalysts – Using high-performance catalysts with better conversion efficiency helps reduce ammonia escape while maintaining NOx removal rates.
3. Real-Time Monitoring – Continuous ammonia escape monitoring allows operators to adjust injection rates dynamically and maintain optimal performance.
What Role Do Gas Analyzers Play in Ammonia Escape Monitoring?
Gas analyzers play a crucial role in detecting and controlling ammonia escape in industrial processes. They provide real-time data on ammonia concentrations in exhaust gases, allowing industries to optimize NOx reduction systems and ensure compliance with environmental regulations. By using advanced gas analysis technologies, facilities can minimize ammonia escape, improve efficiency, and prevent costly maintenance issues.
1. Continuous Emission Monitoring for Compliance
• Many environmental agencies, such as the U.S. Environmental Protection Agency (EPA) and the European Environment Agency (EEA), impose limits on ammonia emissions.
• Real-time monitoring helps prevent regulatory violations, reducing the risk of fines, penalties, and operational shutdowns due to excessive ammonia escape.
• CEMS gas analyzers provide automated data logging and reporting, ensuring transparency and compliance with industry regulations.
2. Early Detection of Ammonia Escape
Gas analyzers enable early detection of ammonia escape, allowing operators to take corrective actions before problems escalate.
• Excess ammonia in flue gas can indicate over-injection of ammonia or catalyst deactivation in SCR systems.
• By continuously measuring ammonia concentrations, gas analyzers help industries adjust ammonia injection rates in real time, improving NOx removal efficiency.
• Detecting ammonia escape early helps prevent the formation of ammonium salts, which can lead to equipment corrosion and efficiency losses.
3. Optimization of NOx Reduction Systems
Accurate ammonia monitoring helps fine-tune SCR and SNCR systems for maximum efficiency.
• In Selective Catalytic Reduction (SCR) systems, maintaining the optimal ammonia-to-NOx ratio is essential for effective NOx reduction.
• If ammonia levels are too low, NOx emissions increase, causing environmental non-compliance. If levels are too high, excess ammonia escapes, leading to secondary pollution and inefficiencies.
• Gas analyzers provide real-time feedback, allowing operators to optimize catalyst performance and reagent dosing, ensuring an ideal balance between NOx reduction and ammonia escape control.
4. Advanced Gas Analysis Technologies for Accurate Measurements
Modern gas analyzers use advanced technologies to measure ammonia escape with high precision and reliability.
Real-time monitoring of ammonia concentration
Ammonia is a gas that easily dissolves into water, there are several common detection methods, but ammonia is toxic and corrosive, the current measurement mainly uses the TDLAS direct measurement method. TDLAS is essentially a spectral absorption analysis technology, which uses the selective absorption characteristics of gas molecules for specific wavelength lasers, and analyzes the changes in the intensity of laser absorption to obtain the gas concentration. TDLAS spectroscopic absorption method can directly measure the concentration of ammonia gas, and can realize accurate measurement from % to ppb.
☑ ESE-LASER-100 Ammonia (NH3) Gas Analysis System
☑ ESE-LASER-100P Portable Ammonia (NH3) Gas Analyzer
☑ ESE-LASER-500 Trace Ammonia(NH3)Gas Analyzer
☑ ESE-LASER-10M Ammonia(NH3) Gas OEM Module
Online monitoring systems are an important part of companies’ efforts to prevent ammonia from escaping. By installing fixed gas analyzers in production areas, companies can monitor ammonia concentration changes in real time. A typical online monitoring system includes a sensor network, data acquisition module, and central control system. Once the ammonia concentration exceeds the preset safety threshold, the system will immediately sound an alarm to notify the operator to take emergency measures.
5. Integration with Automated Control Systems
Gas analyzers can be integrated into plant control systems to enable automated adjustments and optimize emission control strategies.
• Linking gas analyzers with DCS or SCADA allows dynamic ammonia injection adjustments based on real-time data.
• Automated systems reduce ammonia escape and maximize NOx reduction, improving efficiency, cutting reagent use, and lowering costs.
Gas analyzers are essential tools for monitoring in industrial processes. They enable real-time compliance monitoring, early detection of inefficiencies, and optimization of NOx reduction systems. Using advanced gas analysis and automation improves efficiency and ensures compliance with strict environmental regulations.
Conclusion
Ammonia escape is a significant issue in NOx reduction systems, with consequences ranging from environmental damage to increased maintenance costs. Effective control requires optimizing injection rates, using high-efficiency catalysts, and deploying reliable gas analyzers for continuous monitoring. By addressing ammonia escape proactively, industries can improve efficiency, reduce pollution, and meet stringent emission regulations.
