Author(s)

L. Arias, O. Farías, S. Torres & D. Sbárbaro

Abstract

A non-intrusive method for monitoring flames in gas burners is presented. The method is based on the optical analysis of the flame by using a Silicon Photodiodes array and a set of interference optical filters. The covered wavelengths evaluate the formation and behaviour of excited CH* and C2* radicals for confined gas flames. The monitoring of these radicals is carried out in the flame reaction region at the burner exit, where the C2*/CH* ratio signals provide enough information to identify the optimal fuel–air ratio in order to obtain the boiler maximal efficiency and to prevent an incomplete combustion. The experimental results obtained for two power levels, in a boiler of 150 kW, demonstrate that the C2*/CH* ratio provides important information concerning the combustion state and gives a clear indication about the burner adjustment when CO emissions begin to increase to the upper the levels accepted by environmental laws. The fast response and its non-intrusive character give to the proposed optical sensor an important potential to be used in advanced control strategies for the on-line optimization of the combustion process. Keywords: combustion, gas, flame spectrum, photodiodes, optimization, optical sensor. 1 Introduction The monitoring of the combustion state in boilers and industrial furnaces is limited due to the hostile environment. Indeed, the high temperature, the corrosive atmosphere and the limited access to the flame characteristics restrict a reliable diagnostic. The information provided by conventional combustion

Keywords

combustion, gas, flame spectrum, photodiodes, optimization, optical sensor.