Analytical Specialties . : : . PRODUCTS . : : . ICOS Laser Gas Analyzer

ICOS Laser Gas Analyzer Brochure

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General ICOS Presentation

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Dow Chemical paper presented at the 2006 AICHE Ethylene Producers Conference, Rapid On-Line Analysis of Acetylene for Improved Operation of Hydrogenat on Reactors

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ICOS Application Questionnaire

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The ASI ICOS (Integrated Cavity Output Spectroscopy) Laser Gas Analyzer is designed for fast and accurate trace level measurements of many gases

Off-Axis ICOS utilizes a high-finesse optical cavity as an absorption cell (see illustration below). Unlike conventional multipass arrangements which are typically limited to path lengths less than two-hundred meters, an Off-Axis ICOS absorption cell effectively traps the laser photons so that they make thousands of passes on average before leaving the cell. As a result, the effective optical path length may be several thousands of meters using high-reflectivity mirrors and thus the measured absorption of light after it passes through the optical cavity is significantly enhanced. For example, for a cell composed of two 99.99% reflectivity mirrors spaced by 25 cm, the effective optical path length is 2500 meters

Since the pathlength depends only on optical losses in the cavity, and not on a unique beam trajectory (like conventional multipass cells or cavity- ringdown systems), the optical alignment is very robust allowing for reliable operation in the field.

As with conventional tunable-laser absorption-spectroscopy methods, the wavelength of the laser is tuned over a selected absorption feature of the target species. The measured absorption spectra is recorded and, combined with measured gas temperature and pressure in the cell, effective path length, and known line strength, used to determine a quantitative measurement of concentration.

Typical Applications

Acetylene Analysis for Olefins Production

Sub-ppm analysis in finished product or acetylene converter

Product Impurities for Olefins Production

Gases measured include NH3, C2H2, CO, CO2, H2O, H2S at sub-ppm levels (typically one gas measured per analyzer, in some cases two gas measurement may be possible)

Natural Gas Analysis

Sub-ppm measurement of H2S in natural gas

Misc.

Many other gases may be measured with the ICOS analyzer. Contact ASI with application questions

Measurement Advantages

Fast Response (1-20 seconds)

High Sensitivity typically sub ppm detection limits

Interference Free for most applications Unlike other technologies there are typically NO interferences such as paramagnetic offsets or electrochemical interferences

Low LTCO no moving parts, high MTBF for components

Rugged Process Hardened Design The ASI ICOS is designed for process conditions. The electronics are based on the proven TruePeak TDL design. Unlike traditional multipass or cavity ring down analyzers optical alignment is very robust (not dependant on unique beam trajectory)