Dilution Extractive CEMS

Products/ Dilution Extractive CEMS

Dilution Extractive CEMS 

The ESE-1000 continuous flue gas emission monitoring system (dilution method CEMS) incorporates a dilution extractive methodology. This advanced solution employs ultraviolet fluorescence detection, chemiluminescence analysis, and zirconium oxide oxidation mechanisms to quantify SO₂, NOₓ, and O₂ concentrations. Optionally, the system simultaneously determines CO and CO₂ levels through supplementary measurement protocols.
 
Furthermore, the system facilitates wired or wireless transmission of standardized datasets to enterprise-level monitoring hubs and regulatory compliance portals. This comprehensive approach enables real-time monitoring and optimization of industrial emission control systems while ensuring strict adherence to environmental protection mandates.

What is the Dilution Extractive CEMS ?

  • System Composition

    Gaseous pollutant monitoring : SO2, NO, NO2, NOX, etc.

    Flue gas parameter monitoring : flow rate, temperature, pressure, humidity, O2

    System control device, data acquisition system:industrial computer

  • The dilution extractive Continuous Emission Monitoring System (CEMS) incorporates proprietary on-site sample conditioning and gas acquisition technology. During the initial collection phase, a supersonic orifice within the sampling probe initiates precise gas extraction. Subsequently, the system combines dry instrument air with extracted flue gas through controlled pneumatic blending.
     
    This innovative dilution methodology achieves substantial dew point depression through predetermined concentration gradients (typically 25:1 to 250:1). Consequently, the resultant gas mixture maintains thermodynamic stability below site-specific ambient temperature thresholds. The integrated approach obviates conventional moisture removal requirements prior to analytical instrumentation. 

Furthermore, the optimized vapor pressure characteristics prevent interstitial condensation formation across operational temperature ranges. Even after dilution, the sample remains a wet gas, preserving its original moisture content. Thus, the measurement process is classified as a “wet-based measurement,” ensuring accurate analysis without the need for further conditioning.

How does the Dilution Extractive CEMS work?

The initial phase employs a dilution extractive sample probe to introduce extracted gases into the CEM system. Analytical processes necessitate precise dilution of gas samples to mitigate excessive concentrations that might compromise instrument integrity or distort measurement accuracy.

Subsequently, a compressed air treatment assembly purifies, filters particulate matter, and dehumidifies the dilution medium until achieving a dew point below -30°C. Following air preparation, the system dynamically combines flue gas with prepared dilution air at a predetermined ratio through a critical orifice’s calibrated restriction.

Finally, the homogenized mixture flows through dedicated sample lines to a centralized distribution hub, where multiple analytical devices simultaneously access the standardized gaseous medium. This modular configuration optimizes operational flexibility by enabling parallel instrument sampling while maintaining consistent analytical parameters across measurement platforms.

Consequently, the architecture enhances system reliability through redundant sampling capabilities and coordinated data acquisition protocols.

NOX Gas Analyzer

Principle of chemiluminescence method:

When NO is mixed with O3 in the sample, NO2 and O2 in the excited state are generated. The excited state NO2 emits infrared light when it returns to the ground state.
NO+O3→NO2*+O2
NO2*→NO2+hv
The emission spectrum of this reaction is in the range of 600-3200 nm, and the maximum emission wavelength is 1200 nm.
3NO2 +M → 315ºC→
3NO+MoO3
The reactive emission spectrum is in the range of 400-1400 nm, and the peak wavelength is 600 nm.

SO2 Gas Analyzer

Principle of pulsed fluorescence method:


When the sample is irradiated with ultraviolet light with a wavelength of 190-230nm, SO2 absorbs ultraviolet light and produces an energy level transition, and SO2 changes from the ground state to the excited state, that is:
SO2+hv1→SO2*
The excited state SO2* is unstable and instantly returns to the ground state, emitting fluorescence with a peak of 330 nm, i.e
SO2*→SO2+hv2
The intensity of fluorescence is proportional to the concentration of SO2, and the concentration of SO2 can be determined by measuring the intensity of fluorescence with a photomultiplier tube and an electronic measurement system

Dilution Sampling Probe

Function: sampling, filtration, heat preservation, anti-corrosion, dilution, backflushing
Dilution ratio: 1:100
Heating temperature: 180°C
Filtration precision: 2μm

Zero air purging optimizes probe longevity by maintaining stable temperature, dilution gas pressure, and vacuum parameters. Furthermore, the system employs separate gas circuit and electronic modules, streamlining subsequent upkeep procedures.
 
Notwithstanding elevated flue temperatures, the dilution core retains operational integrity. Moreover, operators maintain 180°C heating for both the dilution core and probe assembly, effectively preventing aqueous condensation while minimizing analyte adsorption in transfer lines.
 
Consequently, the reduced sampling volume minimizes particulate accumulation, thereby extending filter service life through decreased clogging propensity. Finally, the hot-wet extraction methodology preserves measurement accuracy by eliminating dissolution artifacts across all monitored components.

Advantages of Dilution Extraction CEMS

Simplified Maintenance and Operation

The dilution method can lead to more stable readings, resulting in less frequent calibration, saving time and resources. Many modern systems feature intuitive interfaces and automated functions that simplify operation.

Prevention of Instrument Damage

This protective measure helps prolong the life of monitoring equipment, ultimately reducing maintenance and replacement costs. By diluting the gases before reaching the analyzers, the risk of damaging sensitive components is significantly reduced.

Real-Time Monitoring and Reporting

The accurate measurement and reporting capabilities of dilution extraction CEMS ensure that data submitted to regulatory agencies are reliable. Continuous monitoring allows operators to detect and address emissions issues promptly, enhancing compliance.

Enhanced Measurement Accuracy

This technique ensures that the sample is representative of the overall emissions, allowing for precise monitoring of pollutants. By diluting the sample gas at a controlled ratio, variations in concentration that could lead to inaccuracies in measurement are minimized.

Environmental Benefits

Accurate monitoring aids in identifying and mitigating excessive emissions, thereby helping to minimize environmental impact. The ability to monitor emissions precisely supports companies in their commitment to sustainable and responsible operations.

Versatility in Applications

The system can be utilized in diverse industrial processes, from power generation to manufacturing, ensuring compliance with environmental regulations. This system effectively measures a variety of pollutants, including NOx, SO2, O2, CO, and CO2, using different analyzers tailored to specific gases.

Advantages of Dilution Extractive CEMS

High Reliability and Low Maintenance Costs​

The dilution system significantly enhances system reliability while reducing operational and maintenance expenses. Its average operating cost is only 1/3 to 1/2 of a direct sampling system.

Condensation-Free Operation

Instant dilution within the probe eliminates condensation effects, removing the need for heated or insulated sampling lines. This prevents potential instrument damage caused by condensation

Real-Time Monitoring and Reporting

The accurate measurement and reporting capabilities of dilution extraction CEMS ensure that data submitted to regulatory agencies are reliable. Continuous monitoring allows operators to detect and address emissions issues promptly, enhancing compliance.

Enhanced Measurement Accuracy

This technique ensures that the sample is representative of the overall emissions, allowing for precise monitoring of pollutants. By diluting the sample gas at a controlled ratio, variations in concentration that could lead to inaccuracies in measurement are minimized.

Efficiency and Simplified Maintenance

Rapid sample gas transmission, reduced maintenance workload, and minimal consumable usage. Additionally, it supports data processing and report generation

Versatility in Applications

The system can be utilized in diverse industrial processes, from power generation to manufacturing, ensuring compliance with environmental regulations. This system effectively measures a variety of pollutants, including NOx, SO2, O2, CO, and CO2, using different analyzers tailored to specific gases.

What are Dilution Extractive CEMS used for?

The application spectrum encompasses thermal power generation, ferrous metallurgy, cement production, waste-to-energy conversion, petrochemical processing, advanced ceramics manufacturing, glass furnace operations, non-ferrous metal refining, and tobacco processing industries.

  • More suitable for sampling in high humidity & dust environment.
    The dilution-based CEMS methodology demonstrates exceptional adaptability in elevated humidity conditions. This system initiates large-scale proportional gas dilution (e.g., 100:1 ratio) at the sampling probe interface, effectively reducing moisture concentrations below critical dew-point thresholds. Consequently, the entire analytical chain operates without moisture removal infrastructure, significantly enhancing operational reliability in saturated gas streams.

 How Dilution Eextractive CEMS Ensures a Stable Dilution Ratio?

Control of Flue Gas Intake

The sampling probe features a supersonic orifice that ensures a constant gas flow rate when the pressure differential across the orifice exceeds 0.46 times the upstream pressure. This condition is maintained as long as the vacuum level behind the orifice is greater than -53 kPa, regardless of changes in temperature or pressure. Venturi tube downstream of the orifice creates sufficient vacuum by directing the dilution air flow, enabling consistent gas intake. The entire process relies on aerodynamic principles, with stable operation ensured by a continuous supply of instrument air (0.6 MPa, 20 L/min).

Control of Dilution Air Flow

The Venturi tube functions as a critical flow restriction mechanism, modulating dilution airflow rates. Multi-stage pressure regulation systems ensure precise pressure stabilization within the dilution air circuit, with a standard operational threshold of 0.35 kPa. Stable pressure conditions preserve homogeneous vacuum levels throughout the Venturi assembly while facilitating continuous flue gas extraction. Furthermore, this process sustains equilibrium within the integrated dilution system, thereby maintaining optimal proportional ratios.

Supersonic Orifice

The supersonic orifice minimizes the influence of temperature and pressure fluctuations on the dilution ratio. By operating at critical flow conditions, the orifice ensures that the volumetric flow rate of gas through it depends solely on the gas velocity, which is close to the speed of sound.

System-Wide Calibration

Calibration gas is introduced at the probe's front end and follows the same path as the sample gas to the analyzer. This method validates the consistency of the dilution ratio and eliminates system-wide errors, ensuring accuracy across the entire system.

Dilution Sampling Probe Design

The probe integrates a critical orifice (supersonic orifice) with a 0.1 µm fine filter to prevent dust blockages. 2.A Venturi tube, powered by pressurized clean air, generates the necessary vacuum. This system uses 3–7 liters of compressed air, which is directed through a nozzle to create suction, ensuring efficient and stable operation of the dilution system.

Dilution Extraction CEMS Designs: Factors to Consider

Sample Conditioning

It is essential to integrate effective sample conditioning units that can remove moisture, particulate matter, and other contaminants. Maintaining appropriate temperatures within the system is vital to prevent condensation, which can skew results. Systems must be insulated and, if necessary, heated to avoid inaccuracies due to temperature fluctuations.

Dilution Ratios

Standard dilution ratios, such as 100:1, may be employed to mix the flue gas with clean, dry air. This dilution must be precisely controlled to match the requirements for specific gases being detected. Incorporating adjustable dilution mechanisms allows operators to modify settings based on real-time conditions of the gas being monitored and regulatory requirements.

Selection of Analyzers

Analyzers must be selected for their robustness and capability to function optimally in the specific environmental and operational conditions of the facility. Different gases require distinct analytical techniques.

System Reliabilities and Maintenance

Incorporating self-diagnostics can alert operators to system malfunctions before they impact data collection. Designing systems that are straightforward to maintain, with easily accessible components, can help ensure technicians can perform regular checks and repairs without significant downtime

Data Acquisition and Handling

The design should facilitate continuous real-time monitoring capabilities to allow for immediate responses to emissions changes, enhancing operational control.Systems must support seamless integration with data reporting tools to ensure accurate compliance documentation can be generated without manual entry, thereby minimizing human error.

Environmental Factors

The design must consider varying environmental parameters and include features that allow the system to adapt. For instance, if ambient temperatures are prone to fluctuation, temperature-regulating equipment needs to be factored into the CEMS design. Robust Material Selection: Materials used in the construction of sampling lines, probes, and other components must be resistant to corrosion and degradation from environmental influences to enhance longevity and reliability.

Supply Dilution Extractive CEMS By Monitoring Gas

SO2/NOx/O2/CO2/CO Analyzer

  • UV fluorescence is used to test
  • SO2 Chemiluminescence is used to test for NOx
  • Zirconia oxidation is used to test O2
  • NDIR or gas filter correlation technique for CO and CO2

Dilution Extractive CEMS By Body Arrangement

  • Flexible design for cabinets
  • Compact for space constraints
  • Single bay available
  • Stainless steel or fiberglass
  • Single or redundant HVAC units
  • Industrial Computer
    Real-time data, calculation, query history, parameter setting and other functions

Dilution Sampling Probe

The sampling probe incorporates multiple integrated functionalities, such as gas extraction, particulate filtration, temperature regulation, corrosion resistance, precision dilution, and automated backflush cycles. This system features a modular split design for electrical and pneumatic circuits. Specifically engineered for gas interface components, premium 316L stainless steel or titanium alloy construction ensures compatibility with diverse industrial emission monitoring scenarios. Moreover, the apparatus continuously monitors and digitally displays three critical parameters: probe thermal conditions, diluent gas pressure levels, and negative pressure chamber metrics through real-time precision tracking. 

Technical Parameters

Measurement FactorsS02, NOx, 02, expandable CO, CO2
Measurement principleS02: Ultraviolet fluorescence method
NOx: chemiluminescence method
O2: zirconia
System RangeS02: (0~50~500)ppm Customisable
NOx: (0~50~500)ppm Customisable
O2: (0~25)%
Sampling MethodDilution Extraction Method
Dilution Ratio1:100/1:200 Customisable
Zero/span drift±1% F.S/24h
Indicated value error±1.5% F.S
Response time<120s
Working environmentIndoor (15~35)°C, Outdoor (-20~50)°C
Operating voltageAC (220±22)V, (50±1)Hz
Signal outputRS232/ RS485/ (4~20) mA

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