TDL – Tunable Diode Lasers

Cemtek TDL (Tunable Diode Lasers)

Model 7000 Laser Based Cross Stack Monitor for EPA Compliance or Process Monitoring

NH3, HCl, O2, CO, H2O, HCN, H2S, CO2, CH4, HF, NO, HDO, D2O

The Model 7000 Laser Monitor is continuous monitor designed to Measure flue gases for both compliance and process monitoring.  The Controller uses a near infrared (NIR) Tunable Diode Laser Absorption Spectrometer System utilizing a single mode “DFB” laser mounted in a thermoelectric cooler for unsurpassed accuracy and performance. Since the Spectral Purity of the laser is high and the selected absorption feature is unique, measurements can be made free of interferences from any other gas.  The measurements are made in‐situ across the stack or duct in either a single or dual pass design depending upon the application.  A Windows based software package is available to display the data on either a host laptop PC or the client’s existing data acquisition system.

Typical Applications:


  • HCl: EPA MATS Compliance Monitoring per PS18
  • NH3 & H2O: Gas Fired Slip Monitoring for Process Control & EPA compliance
  • NH3 Coal Fired slip monitoring for prevention of air preheater pluggage & corrosion
  • O2 & CO: Combustion Control


  • HCl: EPA PC MACT Compliance Monitoring per PS18
  • CO, CO2, O2 Process Monitoring


  • CO, CO2, O2, H2S, NH3 FCC, SRU, Furnaces & Heaters


  • HF, H2S, CO, O2, NH3, Trace H2O: SRU, Reform & Cracker


  • CO, CO2, O2, HF, H2O, NH3, HCN: Process gases

Nitric Acid Production:

  • NH3

Aluminum Smelters:

  • HF in Stack

Steel Smelters:

  • CO, CO2, O2, H2O

Nickel Smelters:

  • H2S, CO, CO2

Copper Smelters:

  • NO

Gold Smelters:

  • HCN

Pulp & Paper:

  • H2S

Nuclear Processing:

  • HF, D2O, HDO


  • HF, HCl, NH3, O2, CO, CO2

Nylon, Carbon fibers, Plastics:

  • HCN, O2

Waste Water Treatment:

  • H2S


  • HF, HCl


  • H2S, CH4, NH3

Tobacco Processing:

  • CO, CO2 as early fire detection

Automobile Exhaust:

  • CO, CO2


  • HF

Thermal Oxidizer

  • O2

Features & Benefits

TDL (Tunable Diode Laser) technology for unmatched accuracy & reliability

High sensitivity ppb to percent level measurements

One analyzer can be used for up to 8 measurement points

Performance designed Process Monitor

Gas sampling/conditioning not required

Corrosive/toxic applications

Calibration not required

Exceeds EPA CEMS Regulation requirements MACT & MATS ‐ Draft PS-18 Compliant

Boiler MACT O2 and CO Compliance

Approved Zero & Span Calibration checks

Extremely Fast (<1 second) response time

Compact and simple to install

Ambient conditions from ‐ 40° to 60° C

Operates in high dust/moisture applications

Unaffected by stack/duct alignment changes

Laser located in controller allowing for simple signal control and diagnostic access

Moisture can be added as a second channel

Off Stack/Process extractive option

Hazardous Area Div I & II Options