UV-FTIR
Using both UVDOAS and FTIR technology allows the Cerex UV-FTIR to be one of the most sensitive continuous emissions and stack monitoring solutions in the market
Overview
Cerex’s UV-FTIR is an FTIR continuous multi-gas analyzer, engineered specifically for low cost, high performance monitoring of cross process applications. Capable of simultaneous monitoring of more than 350 compounds in Cerex’s FTIR library, the FT-5000 provides continuous emissions monitoring without having to extract the gas samples from the stack.
Cerex has the capability to adapt analyzers to extractive, cross-stack, and insitu scenarios, whilst safely providing data in real-time. For extractive applications, heated tube bundles are available; for cross-stack applications, transmitters and reflectors are available; for in-situ applications, gas probes are available. The UV-FTIR can be customized to fit your specific application needs.
Offering true part-per-billion (ppb) detection limits in an easy to operate package, the Cerex UV-FTIR’s air-conditioned system can reliably deliver unattended, continuous real time monitoring of ultra low ppb concentrations of individual gas species with absorption features spanning the IR spectrum from 2 to 14 microns. There are no tedious ongoing calibrations, or additional costs for sample handling, wet chemistry, carrier gas, or sorbent filters. Results are immediate, and the raw data containing all the information necessary for gas identification and quantification is always saved.
How it Works – FTIR
Fourier transform infrared spectroscopy (FTIR) is the preferred technique used to obtain an infrared spectrum of absorption or emission of a solid, liquid, and gas.
The UV-FTIR operates by sending a beam of infrared light through a 20 meter sealed sample cell within the instrument. The IR beam is directed by a series of optics to an ultra-sensitive cryo-cooled MCT detector where minute changes in IR absorption are sensed due to trace concentrations of individual gases. A classical least squares regression analysis compares the measured absorption spectrum to calibrated reference absorption spectra files. Beer’s law is then used to determine gas concentrations (Beer-Lambert Law).
The result of coupling our proven detection system with a 20 meter internal optical sample path and CMS real time analytic software is an industry leading FTIR multi-gas analyzer.
How it Works – UVDOAS
UVDOAS (Ultraviolet Differential Optical Absorption Spectroscopy) is a monitoring technique which uses the absorbance of UV light to identify and quantify gases within a sample. Gases absorb unique wavelengths of light, creating a unique fingerprint of each compound within the absorbance spectrum; the amplitude of the absorbance wavelength is proportional to the concentration of the gas present in the sample (Beer-Lambert Law).
In addition to FTIR technology, the Cerex UV-FTIR uses a collimated beam of light and fiber optics to obtain these spectral fingerprints and then, using a pattern-matching classical least squares regression analysis, compare them to a vast library of stored references. The result is a real-time concentration number of the gases of interest.
Cerex’s UV-FTIR analyzers feature:
- Dual Channel FTIR and UVDOAS continuous emissions monitoring
- All criteria gases with one analyzer
- Cross stack and parallel cell models
- In situ stack monitoring, non contact
- Outdoor model available
- Operational range in ppb, ppm, and higher
- Continuous, real time monitoring of over 400 individual gas species
- 100+ USEPA HAPs
- Acids, VOCs, SVOCs
- Anesthetics / Toxics
- Output options for alarm, data, and process control are available
- Integrated Ethernet / WiFi
- PC or Smartphone Remote Control
- Automatic saved records of data
- Customizable audible, visual and email alerts
UV-FTIR
- Packaged in an type 4X - IP54, thermoelectrically cooled, enclosure
- Environmentally sealed
- Operating temperature range of -40°F to 131°F (-40°C to 55°C).
- Suitable for corrosive environment system deployment
We recommend...
Maintenance
- Recommend quarterly inspection and possible replacement of the air intake filters if operated continuously
- Fans are rated to 70,000 hours at 40°C
- IR source life time is approximately 2 years
- Stirling cooler (detector cryocooler) guaranteed for 2 years before refurbishment is required
- A maintenance free, thermoelectrically (TE) cooled, detector is available for some applications
Benefits of FTIR -
Extensive Library with Options for Customization
Cerex has over 385 compounds available for detection with the UV-FTIR. If your compound is not one of the compounds already available within our database, the UV-FTIR may import gas spectra from the numerous FTIR databases on the web (NIST, EPA, PNNL, etc.)
If you have a compound that is not available in a public database, we may be able to work with you to develop a custom spectrum. Detection limits are a function of the IR detector, installed path length, and site conditions. The detection limits shown have been empirically determined from bump tests of fielded instruments at full path-length.
| Type | Compound | MDL PPB | ||||
| Criteria | Sulfur Dioxide | 300 | ||||
| Volatile Organic Compounds | Acrolein | 15 | ||||
| 1,3 Butadiene | 4 | |||||
| Styrene | 8 | |||||
| BTEX | Benzene | 30 | ||||
| Toluene | 100 | |||||
| Ethylbenzene | 25 | |||||
| m-Xylene | 100 | |||||
| o-Xylene | 300 | |||||
| p-Xylene | 300 | |||||
| Alkanes | Pentane C5 | 4 | ||||
| n-Hexane C6 | 3 | |||||
| TVOC | Methane C1 | 3 | ||||
| NMHC | Ethane C2 | 8 | ||||
| NMNEHC | Butane C4 | 4 | ||||
| Propane C3 | 4 | |||||
| Formaldehyde | 7 | |||||
| Propene (propylene) | 6 | |||||
| Ethene (ethylene) | 4 | |||||
| Acetylene | 4 | |||||
| Acetaldehyde | 5 | |||||
| Methanoic Acid | 5 | |||||
| Methanol | 4 | |||||
| Other | Hydrogen Cyanide | 10 | ||||
| Hydrogen Fluoride | 4 | |||||
| Ammonia | 3 | |||||
| Hydrogen Sulfide | 450 | |||||
Benefits of UVDOAS -
Low detection limits
Low detection limits
All gas compounds absorb UV light energy at specific wavelengths. In addition to FTIR technology, The UV-FTIR detects gas compounds found present in a reflected UV light beam. For a gas compound to be detected by UV-FTIR analyzers, there must be enough UV energy present at the wavelength's point of absorption.
Cerex offers two UV bulb types for the UV-FTIR - Deuterium and Xenon. The primary reason to select one bulb type over the other is to have sufficient energy for analysis for your compounds of interest.
Deuterium
- Monitor distances up to 225m in a mono-static configuration or 450m in a bi-static configuration
- More energy below 240nm
- Required to detect 1,3-Butadiene (C4H6), ammonia (NH3), nitric oxide (NO), and others
Xenon
- Measuring longer distances, 1km or more, with a single instrument
- Easier to align at longer distances due to the high visible component of light
UV-FTIR Specifications
| General Parameters | |
| Part Number | Shepherd FTIR |
| Analyzer Type | Multi-gas portable point analyzer |
| Technology | Fourier Transform InfraRed (FTIR) Differential Optical Absorption Spectroscopy (DOAS) |
| Performance | Available with standard HAP (385 compound & 62 Compound), Criteria, Hospital and custom gas detection libraries. |
| Data Output Rate | User selectable from 5 seconds and up Typical output rates are 30s, 60s, 120s, or 300s Time weighted average available for user defined periods (8 hour, 12 hour, 24 hour) |
| Measurement Principle | Beer-Lambert Law |
| Measurement Technique | Classical Least Squares (CLS) regression analysis; optional Partial Least Squares (PLS) |
| Operating Temperature | 0°C to 35°C (Optional Air Cooled Model)
|
| Storage Temperature | -40C° to 60C° |
| Power Supply | 100 to 130V or 200 to 240VAC/50-60Hz |
| Power Consumption | 240W MAX |
| Instrument Cooling | Air Cooled |
| Installation | Fixed mount or tripod mount (open path analyzer mode) Bench-top (point analyzer mode) |
| Dimensions | 42.1" x 21.9" x 23.3" (107cm x 55.7cm x 59.1cm) |
| Weight | 85 lbs (38.6Kg) |
| Measuring Parameters | |
| Concentration measurement accuracy | ±5 % Reading TYP |
| Concentration measurement precision | ±5 % Reading TYP |
| Interferent Mitigation | Real time spectral subtraction and residual subtraction, multi-peak analysis. |
| Zero point calibration | Simultaneous dual mode natural zero and/or synthetic zero on gas by gas basis. Automated compound specific background selection. |
| Software | |
| Real Time Operating Software | Cerex Continuous Monitoring Software (CMS) |
| Operating System | Windows 10 Pro |
| Post Collection Analysis Software | Cerex Data Processor |
| Operating System | Windows 7, 8, 10 |
| Spectrometer | |
| Apodized Resolution | User selectable: 0.5 cm-1, 1 cm-1, 2 cm-1, 4 cm-1, 8 cm-1, 16 cm-1, 32 cm-1 |
| Scan frequency | 6 scans/s @ 32 cm-1 |
| Detector | Stirling Cooled MCT (standard) TE Cooled MCT (application dependent) |
| Detector temperature | 77 K (Stirling cooled MCT) |
| Source | SiC, 1550K |
| Beamsplitter | ZnSe (standard) |
| Window material | ZnSe (standard) |
| Wavenumber range | 600-4200 cm-1 |
| Temperature stability | < 1% per C⁰ |
| Frequency repeatability | < 0.001 cm-1 @ 1918cm-1 |
| Frequency accuracy | < 0.06 cm-1 @ 1918cm-1 |
| Short term stability | < 0.09% |
| Maximum signal to noise ratio | 50,000: 1 (RMS, 60s, 4 cm-1, at peak response) |
| Signal sampling | 24-bit ADC |
| Quality Assurance Hardware | |
| Type | Internal linear multi-pass cell permanently mounted in beam path. External window removable. |
| Calibration gas inlet | Quick Connect QA Adapter: 1/4" Swagelok |
| Calibration gas outlet | Screw-in Exhaust Adapter: 3/8" Swagelok |
| Path Length | 19.2 m |
| Volume | 3.4 L |
| Maximum sample pressure | 1 PSI |
| Pressure and temperature measurement | Integrated pressure and temperature sensor |
| Integration | |
| HMI | Touchscreen (standard model) |
| Digital Interface | RJ45 Ethernet LAN Port for local or internet based remote data and access using MODBUS TCP, VNC, and remote desktop. Spectral data may be stored locally, on a NAS, or disabled. Industrial external wireless option available. Type A USB for data retrieval and peripheral accessories. |
| Power Connection | Environmentally sealed circular Amphenol bayonet connector. |
| Integrated Computer | Embedded industrial PC |
| Options | |
| Integrated Wind Mapping | Three dimesnional ultrasonic anemometer with temperature measurement. Data integrated into CMS data tables and available via MODBUS. |
| Integrated Data Acqusition | External ports with data integration for particulate or ancillary co-located analyzers (TDLAS laser, electrochemical, etc.). |
| Data Output | MODBUS over RS-232, RS-485. MODBUS over TCP-IP is standard. |
| Analog Output | 8 channel configurable 0-24mA (4-20mA with extended range) |