Research On Ash And Slag Monitoring Technology Of Power Station Boiler Water Wall

China’s thermal power still occupies a dominant position,thermal power generation is to use coal as the main fuel,when the coal is burned out of the flammable volatile in the boiler furnace,a large amount of ash will be produced.Therefore,the phenomenon of ash deposition and slagging will occur on the heating surface of each part of the boiler.Slagging will reduce the heat transfer capacity of the heating surface in the furnace,lead to the rise of the flue gas temperature at the furnace outlet,and affect the safe and economic operation of the boiler.The power station boilers in our country generally use timing and quantitative methods and procedures to deal with the problem of soot blowing.Because this operation mode does not know the actual situation of the heating surface in advance,it uses this way to blow ash,so there will be many potential problems,which may bring adverse effects at any time.This paper analyzes and studies the existing boiler heating surface monitoring systems at home and abroad,establishes the monitoring model of water wall fin end,and achieves the purpose of measuring the slagging thickness by monitoring the change of wall temperature from fin tip.Firstly,according to the heat transfer mode in the furnace of coal-fired boiler,the theoretical formula between the temperature change of fin end and the ash thickness is derived by using the one-dimensional steady-state heat conduction law when ash deposition and slagging occur on the heating surface of water-cooled wall.Based on the heat balance equation,the finite element model of water wall is established to calculate the temperature distribution of water wall with or without ash,and the difference between the theoretical value and the calculated value under the same condition is compared.Finally,the thermal conductivity of ash material is measured,and the monitoring system composed of tubular resistance furnace,temperature controller,K-type thermocouple,intelligent temperature circuit detector and heat flow sensor is designed.When the temperature at the center of the tubular resistance furnace is changed to monitor the surface temperature change of the ash sample away from the center of the furnace,the relationship between the temperature difference of the measuring point and the ash thickness is established to verify the feasibility of the monitoring model.