Spectra-1 TDLAS - Open Path Gas Detection Brochure

SPECTRA-1 TDLAS Open Path Gas Detection Applications: Environmental Monitoring Fugitive Emission Work Greenhouse Gas Reduction Fertilizer Production Confined Feeding Operations Aluminum Manufacturing Landfill Facilities Methane Absorption-25000-20000-15000-10000-500005000100001500020000250001 8 15 22 29 36 43 50 57 64 71 78 85 92 99 106 113 120 127 134 141 148 155 162 169 176 183WavelengthIntensitySeries1 TDLAS Gas Detection Principles Most laser gas detection monitors are based on tuneable diode laser absorption spectroscopy (TDLAS). The identification of gas species by absorption spectroscopy goes back several decades. A molecule can be identified by its characteristic absorption spectra. If the frequency (or wavelength) of the infrared (IR) light source matches the vibrational frequency of the molecule, then light will be absorbed. The Beer-Lambert law is the linear relationship we use to calculate molecule concentration (ppm) from the characteristic absorption a molecule exhibits. Infrared Absorption spectra of Methane (Absorbance vs. Wavelength (µm)) One of these absorption features is chosen that does not coincide with any other molecule absorption spectra. The wavelength of the tuneable laser is set very close to the absorption feature we want to measure. A laser is ideally suited for this - as the light output is monochromatic. The laser wavelength is then scanned back and forth over this absorption feature. The resulting change in laser intensity when scanned over the absorption feature provides the information required to calculate the molecule concentration. Laser intensity scan over 100ppm-m Methane @1.645µm absorption feature PPM-M and PPM Discussion Open path monitors measure the total amount of a specific molecule (gas) in the path between the laser source and the reflector. The result of this “total path” measurement is given as ppm-m. A reading of 100 ppm-m is converted to ppm by dividing by the path length. A path-average concentration measurement is provided by the open-path gas monitor. If one requires more information (Is the concentration of gas uniformly distributed?) shorter optical paths may be chosen to determine distribution of the monitored gas species. Sensitivity and MDL’s Sensitivity and MDL are determined by the particular molecule absorption line chosen, and the optical path length. Absorption line widths and line strengths are different for each absorption line, and molecular species. We have the ability to increase or decrease the optical path length to increase or decrease our sensitivity to the molecular species we are monitoring. Detectable Gases: HF, CH4, NH3, CO2, CO, HCN, C2H2, C2H4, C2H6, H2S and others. SPECTRA-1 Details: Spotting scope: ? Spectra-1 alignment with retro-reflector 2 X 20 character LCD display: ? gas concentration ? ppm or ppm-m ? distance to retro-reflector ? signal level bar graph ? signal level % reading ? configuration/menu display Keypad for system configuration: ? distance to retro-reflector ? gas concentration - ppm or ppm-m ? averaging time 1 to 60 seconds ? maximum signal level set (i.e. 90%) ? minimum signal level set (i.e. 5%) ? RS232 com port setting (baud rate) ? logging options ? logged data transfer – USB memory stick ? calibration settings ? Spectra-1 settings output ? display IP address Australia and New Zealand : Norditech Pty Ltd Unit 36, 70 Holbeche Road Arndell Park NSW 2148 Australia P: +61 2 9622 6327 F: +61 2 9622 6340 info@norditech.com.au www.norditech.com.au PKL Technologies Inc. Edmonton, Alberta Canada (780) 486-9564 sales@pkltechnologies.com www.pkltechnologies.com