Flame Detection Of A Marine Supercharged Boiler And Simulation For Drum Water Level Based On Radiative Energy Signal Of Furnace

The pulse of flame in the furnace of marine supercharged boiler will affect drum water level significantly, therefore, real-time detection of flame is very important to stabilize drum water level.This paper summarizes the structure and working characteristics of a marine supercharged boiler, based on that, describes the furnace flame detect system installed on that boiler. After analyzing and discussing the flame images captured from experiments, a method to calculate Radiative Energy Signal (RES) is proposed. Analyses of RES show that working characteristics of the marine supercharged boiler cause fierce pulse of flame in the furnace, which makes heat absorption rate of riser change frequently with that, and finally leads to a fluctuation of drum water level.Taking structure of convective evaporation tubes and fluxion characteristics of flue gas into consideration, this paper studies the heat transfer in the evaporation system. By combining water wall with convective evaporation tubes, heat absorption rate of riser is obtained from the overall heat absorption rate in the furnace and heat absorption rate of the convective evaporation tubes outside furnace. The traditional thermal calculation can not reflect real-time heat absorption rate of riser, however, after gain relationship between RES and heat absorption rate of riser, this paper introduces heat absorption rate of riser calculated from RES into the dynamic mathematical model of evaporation system, in this way, dynamic characteristics of the steam-water system captured by the model are able to reflect the real-time combustion condition of flame in the furnace.Simulation programs are written with Fortran. Because of the application of interpolation method, simulation programs run quit fast. Respond characteristic curves obtained from simulation experiments are deeply researched. This paper shows that volume of steam and water under water level in the drum change differently after step disturb, and the integrative action causes the"false drum water level"phenomena.Simulation results of drum water level fluctuated by heat absorption rate of riser (RES) are given, analysis shows that pulse of heat absorption rate of riser leads to a significant fluctuation of drum water level. There is a great potential to control drum water level in advance by introducing RES into control system.