Industrial applications of temperature and species concentration monitoring using laser diagnostics

Abstract

Industrial applications of laser diagnostics have been demonstrated for the purpose of clarifying combustor chemical reaction mechanisms, as well as temperature and harmful substance monitoring in large-scale burners and commercial plant exhaust ducts, and the combustion control of commercial plants. Laser induced fluorescence (LIF), laser induced breakdown spectroscopy (LIBS), and tunable diode laser absorption spectroscopy (TDLAS) have accordingly been applied in various industrial fields. In this study, temperature and species concentration were measured inside gas turbine combustors, a diesel engine, and a large-scale industrial burner using LIF. This technique introduces a new tool with respect to practical combustors for the analysis of NO formation characteristics, turbulent flame front structure, and differences between standard and improved combustors. On-line monitoring of trace elements to the ppb level was also successfully demonstrated using LIBS. The automated LIBS unit was found to be capable of monitoring trace element concentration fluctuations at ppb levels with a 1 min detection time under actual plant conditions. In addition, real-time measurement of O2 and CO concentrations in a commercial incinerator furnace was performed using TDLAS to improve the combustion control. By using the multiple-point laser measurement results to control secondary air allocation, higher secondary combustion efficiency was achieved, and CO concentration (considered to be a substitute indicator for dioxins) was reduced from 11.9 to 8.0 ppm.

Flow–flame interactions causing acoustically coupled heat release fluctuations in a thermo-acoustically unstable gas turbine model combustor

“…Published by Elsevier Inc. All rights reserved. doi:10.1016/j.combustflame.2010.07.011 from simple, unconfined flames [18,19] to high-temperature, highpressure combustors using complex fuels [20][21][22][23][24][25][26]. However, the simple flame configurations are typically designed to study one particular fundamental process and do not describe the complex flow-flame interactions occurring in practical systems.…”

Lock-in-detection dual-comb spectroscopy

“…For example, multi-channel LID-DCS enables simultaneous monitoring of different gas samples without the time delay of FFT calculation in DCS. Also, simultaneous monitoring of different absorption lines in the same gas sample makes it possible to determine the gas temperature together with gas concentration [34]. These will be a powerful tool for analysis of combustion process in industry.…”

Industrial Applications of Tunable Diode Laser Absorption Spectroscopy

“…There are several specific and useful atoms or molecules in each industry [38][39][40][41]. For example, HF is an important species for the aluminum making industry because the aluminum smelting process utilizes alumina(Al 2 O 3 ) and cryolite(Na 3 AlF 6 ) resulting in the HF emission [39].…”