How Does It Work ?
OVERVIEWA continuous emission monitoring system (CEMS) is the total equipment necessary for the determination of a gas or particulate matter concentration or emission rate using pollutant analyzer measurements and a conversion equation, graph, or computer program to produce results in units of the applicable emission limitation or standard. CEMS are required under some of the EPA regulations for either continual compliance determination(s) of the standards.
Why Emission Monitoring?
- Compliance with environmental legislation
- Collecting data for environmental impact assessments
- Collecting data to assess process efficiency and process control
- Assessing the performance of a pollution control device / scrubber
Gas Analyzers and Monitoring TechnologiesA continuous emission monitoring system(s) (CEMS) is an integrated system that demonstrates source compliance by collecting samples directly from the duct or stack discharging pollutants to the atmosphere. A CEMS consists of all the equipment necessary for the determination of a gas or particulate matter concentration or emission rate. This includes three basic components:
- Sampling and conditioning system
- Gas analyzers and/or monitors, and
- Data acquisition system (DAS) and controller system.
- In situ – analyzers located directly in the stack or duct.
- Extractive – CEMS capture a sample from the duct or stack, condition the sample by removing impurities and water, and transport the sample to an analyzer in a remote, environmentally protected area.
Anodyne ServicesAt Anodyne, we offer Emission Monitoring System for process, boilers, coke ovens, furnaces (both coal and electricity based), Cement Kilns and other applications.
Category Of Industries Covered
- Iron and Steel, Zinc, Copper
- Power Plants
- Chemical Industry
- Oil refinery and petrochemicals
- Food and beverage
- Distillery, Brewery, Malting
- Cement Manufacturing and grinding
Available TechnologiesWe offer tailor-made and customized solutions for analysis of gases, dust measurement.
Our gas Analyzers employ:
- Cold dry extractive principle, coupled with
- Particulate filters (Sintered and Pleated Filter)
- Sample dryers (Dehumidifiers and Dessicant Dryers)
- Peltier Cooling System at Probe
What Is It?
A + B ->AB* ->Products + Light
This light emitting detection principle is suitable for Gases:
- Nitrogen Oxides (NOx, NO, NO2)
- Ammonia (NH3)
Chemiluminescence method allows detection of extremely low concentrations of NO, being not only fast but also very sensitive and NO specific. The reaction scheme of NO and O3 by chemiluminescence is as follows:
NO + O3 NO2+ O2 [ 1 ]
NO + O3NO2* + O2 [ 2 ]
NO2* NO2 + hv[ 3 ]
NO2* + M NO2+ M [ 4 ]
The radiation emission is in the wavelength between 600 and 3000 nm with an intensity maximum at approximately 1200nm. This chemiluminescence signal is detected photo-electrically.
- Band- Pass filters for passage of only those wavelengths, which are emitted by NOx and NH3 molecules separately.
- Signal is proportional to the NO concentration of the sample gas.
- Sensor doesn’t come in contact with gas
- Inbuilt Ozone generator using fresh air from atmosphere
- Inbuilt NO2 – NO converter
- Excess Ozone Removal
- Dust removal
- Water vapour removal
What Is It?
- NDIR (Non-Dispersive Infrared) measurement that allows all light to pass through sample.
- Dispersive Infrared measurement for passage of selected wavelengths to pass through sample.Dispersive IR detectors are usually used in benchtop analytic instruments for their ability to scan a broad wavelength range.
Non Dispersive Infra-Red technique is highly specific as it chooses gas specific infrared absorption wave length of the target gas by cutting off all other wave lengths. This technique is cost effective and reliable for measurement of gas concentration in parts per million range.
Considering these advantages, NDIR is available for:
- Sulphur Dioxide (SO2)
- Nitrogen Oxides (NO, NO2)
- Carbon Dioxide (CO2)
- Carbon monoxide (CO)
- Water vapor (H2O)
NDIR is based on absorption of infrared radiation, for specific wavelengths when a sample of gas is exposed to IR radiation.
The basic components that form a part of this technology and instrument are:
- Two identical tubes, namely sample gas flow cell and reference tube.
- IR radiation source or lamp
- IR detector
- Gas filter
Continuous emission of IR radiation to the gas flow cell (with gas sample) and reference cell (with reference gas generally N2) generates two separate signals, which are detected by the IR detector.
The difference of the two signals, is directly proportional to amount of absorbing gas, resulting in ppm levels/concentration of gas.
With wide range of applications for gas detection, lower cost and ease of operation, electrochemical gas sensors have gained popularity in the field of Continuous Emission Monitoring. Analyzers based on electrochemical principle, are significantly cost efficient, and support ease of maintenance, however the life of the sensor for continuous measurement is around 1 year, which is significantly very less as compared to NDIR sensor life of 3 – 5 years and UV sensor (life > 5 years).
However, with respect to current economical instability and plunge, this technology has become widely applicable for low cost options.
What Is It ?
In this type of sensing mechanism, the sensor comes in contact with the type of gas to be sensed / monitored or detected, thus not so advantageous over NDIR and UV based sensing technology.
Please refer to the next tab for the gases that can be monitored.
- Sulphur dioxide (SO2)
- Nitrogen Oxides (NOx)
- Carbon Monoxide (CO)
- Oxygen (Zirconia based and amperometric)
- Hydrogen Chloride gas (HCl)
- Hydrogen fluoride (HF)
- Hydrogen Sulphide (H2S)
- Ammonia (NH3)
- Chlorine (Cl2)
- Hydrogen (H2)
TDLAS (Tunable Diode Laser Absorption Spectroscopy)
The laser signal from the Multi-Channel System is sent through a fibre optic cable to the remote head or duct probe where it is emitted and propagates through the atmosphere to the retroreflector. It then returns to the cell where it is focused on to a photo diode detector. The detector converts it to an electrical signal which travels through a coaxial cable to the electronics in the Multi-Channel System.
A portion of the laser beam is passed through an on board reference cell to provide a continuous calibration check. These two optical signals are converted into electrical waveforms which the computer processes to determine the actual concentration of gas along the optical path. The computed gas concentration is then displayed on the rear panel of the instrument, and can be transmitted to a computer where the data can be collected, stored, and graphically displayed.
For industrial applications a 4-20mA, serial, MODBUS, TCP/IP, and dry-contact relay outputs are also available.
- Carbon Monoxide
- Carbon Dioxide
- Hydrogen Sulphide
- Hydrogen fluoride
- Hydrogen cyanide
- Hydrogen chloride
- Nitrous Oxide
- Water vapour