Tunable diode lasers as continuous emission monitors for thermal waste treatment processes

摘要

In this paper the ongoing program to develop and apply a family of on-line process monitors is described. This technique detects molecular gas-phase species by optical absorption using vibrational transitions in the near-infrared region. Near-infrared, tunable diode lasers are used that emit extremely narrow, single-mode radiation. Current efforts include laboratory work to identify the optimum absorption lines for the molecular species of interest. Sensors based on tunable diode lasers are being developed in parallel with this scoping work. One such instrument, designed to monitor ammonia, has been constructed and field-tested; its specification and performance are discussed.