Research On Acoustic Soot Blowing Technique Of Economizer

The heat exchanging of the tube could result in high energy consumption,high pollution,low efficiency and even the equipment failure.One of the main causes is that the heat exchanger surface of the economizer could get low temperature corrosion.The classic soot blowing may get the disadvantages of high cost,inconvenient operation,it also need to be operated off-line during the fixed period and gets the blind spots.The acoustic soot blowing method can be operated online and it guaranteed the timeliness.However,this kind of technology developed slowly due to its low-strength and the peculiarity,which is the practice of acoustic soot blowing is prior to the theoretical research.The research on acoustic blowing theory and technology in this paper has a strong theoretical and practical significance for promoting the development of this technology.This research started at the learning of the causes,the progress,the characteristics and the categories of the soot formation when the low temperature corrosion occurred in the heat exchanging of the tube.It combined the solid mechanics,hydromechanics and pressure acoustics as the theory and built some models such as sound-solid coupling mathematical model and acoustic coupling mathematical model,it also described the interaction among the sound field,the heat-exchange pipes,the deposit and the high temperature gas.On this basis,it took the H-type finned tube of the 300 MW boiler as the example and used the software named COMSOL Multiphysic to complete the simulation,and then took this as the economizer's coupling model of the sound,the solid and the flow.The research variables are defined as frequency of sound wave(10Hz-200Hz),the acoustic intensity(50dB-200 d B),angle(vertical or parallel)of the acoustic soot,the distribution of the sound(diagonal arrangement or hedge arrangement)and the flow property of the gas(windward or leeward).On the basis of the economizer's acoustic soot blowing model.Then the simulation result could be obtained by comparison of different factors including stress distribution,sound pressure level distribution,movement trend,deformation degree and displacement.Aim at the system this research showed,it set the best soot blowing mode,the frequency set to be 20 Hz,the sound strength set to be 130 dB,the angle is vertical and the style set to be diagonally arranged.The soot blowing logic of 4 sound sources is given,and the soot-blowing cycle is determined by real-time monitoring of the ash state of the surface area of the heat exchanger.In order to overcome the shortcomings of blind soot blowing,a intellect acoustic sootblowing system for economizer was designed in combination with soot blowing strategy.Mainly include: sound wave generation module,soot blower logic control module,dust accumulation status monitoring module and upper computer monitoring software.These achieved the acoustic soot blowing in both effect and necessarity.