Accession Number : ADP004481

Title :   Description of a Chemiluminescent Detector System Specifically Designed for Monitoring Airborne Hydrazine Propellants, Hydrazine, Monomethylhydrazine and Unsymmetrical Dimethylhydrazine,

Corporate Author : THERMO ELECTRON CORP WALTHAM MASS

Personal Author(s) : Rounbehler,D. P. ; Goff,U. ; Fraim,F. ; Fine,D. H. ; Holtzclaw,J. R.

Report Date : AUG 1984

Pagination or Media Count : 8

Abstract : A new prototype ambient air monitoring system designed to specifically detect airborne levels of all three of the commonly used hydrazine propellants, hydrazine (HZ), monomethydrazine (MMH) and unsymmetrical dimethylhydrazine (UDMH) is presently being developed and evaluated. The basic system consists of a modified nitrogen oxide (NO) chemiluminescent detector equipped with a dual-channel air sampling system in which sampled air is split equally between a reference channel and a hydrazine channel. The hydrazine channel differs from the reference channel in that 1 to 5% of the sampled air is replaced by nitrogen gas containing 10% acetaldehyde (approximately 3 to 5000 parts per million (ppm) acetaldehyde in the air stream). The added acetaldehyde rapidly converts airborne hydrazines to their respective hydrozones or azine derivatives. The air samples in both channels are heated to 750 C in a pyrolyzer containing a nickel oxide catalyst which rapidly converts most airborne nitrogen compounds, including oxides of nitrogen, to molar equivalent amounts of NO. The NO produced by the oxidation is then combined with ozone (O3) in an evacuated reaction chamber resulting in an infrared emitting chemiluminescent reaction which is proportional to the NO concentration in the gas stream. The chemiluminescent reaction chamber is equipped with an infrared filter and a highly sensitive photomultiplier tube which is similar in design to that routinely used by commercial NOx detectors to monitor how part-per-billion (ppb) levels of atmospheric NO and NOx.

Descriptors :   *ENVIRONMENTAL MANAGEMENT, *AIR POLLUTION, *HYDRAZINES, *PROPELLANTS, MONITORS, CHEMILUMINESCENCE, DETECTORS, MONITORING, DETECTION, METHYL HYDRAZINES, SAMPLING, NITROGEN OXIDES, INFRARED RADIATION, SYMPOSIA

Distribution Statement : APPROVED FOR PUBLIC RELEASE