High temperature electric furnace lining life directly affects the whole service life of the high temperature furnace, real-time monitoring of high temperature furnace lining erosion state, adjust operation strategy, and take effective measures, to protect the furnace can extend the life of the high temperature furnace. Today is mainly about how to detect high temperature corrosion of furnace lining, introduced several practical and feasible solution.
More than 1, the thermocouple method
Is in a protective sleeve tube is equipped with several branch length range of thermocouples, and then install it in the brick lining need to detect, through the measurement of the thermocouple temperature change about the erosion of masonry. When each point temperature and the temperature gradient between the basic stability, when the brick lining gradually eroded to a certain place, where the couple will be destroyed, the temperature signal will appear abnormal.
Resistance method 2,
Embedding resistance element is inside of furnace lining, the sensor front aligned with lining the inner surface, through the wire connected to measurement system, the resistance value of resistance element is related to its length, with the loss of resistance element and lining synchronization and resistance change, using the corresponding measuring instrument measured element output signals that can be on-line measurement of the residual thickness of the lining.
3, capacitance method
Capacitance and resistance method similar to the inside lining embedding coaxial circular capacitor sensor, capacitance value into corresponding relationship with length, can be measured by capacitance value to determine the thickness of the high temperature furnace masonry.
4, ultrasonic method
Is the use of the characteristics of ultrasonic propagation in solid medium thickness, ultrasonic wave incident at certain temperatures into the furnace lining into the furnace, using the ultrasonic transmission time of incidence and reflection in the furnace lining, the residual thickness of lining.
5, heat flow test
According to thermodynamics, temperature difference, thermal conductivity and wall thickness determine the heat flux intensity, the high temperature furnace lining, the coefficient of thermal conductivity is fixed, the temperature difference and heat flux intensity of wall thickness can be obtained.
Heat flow detection sensor installed at the site of the lining temperature is low, water temperature difference through hearth cooling wall, calculate the heat flux intensity, coupled with temperature measuring thermocouple in brick lining measured temperature value, calculate out wall thickness.
6, model inference method
Application is to use the thermocouple as detecting element, such as thermodynamics theory to establish the hearth and bottom temperature field mathematical model, through software programming and numerical analysis method, to calculate the hot metal solidification of line and line of the carbon brick erosion about location.
7, stress wave method
Stress wave signal has a high sensitivity of structure defects, when the stress wave propagation in the medium, such as holes, cracks discontinuous interface, reflection, refraction, scattering occurs and pattern transformation, the characteristics of stress wave can be used to determine the thickness of cooling stave.
The future development trend of the lining thickness is different method combination. High temperature furnace, blast furnace body, furnace waist long thermocouple or resistance method can be used; And at the bottom of the furnace hearth heat flux method or model inference method can be used; When online monitoring, stress wave method can be used.