One of the main problems currently facing coal-fired power plants is the handling of combustion ash deposits attached to the furnace walls. These ashes are called Water Wall Slag. The accumulation of ash on the boiler heat exchanger tubes hinders heat absorption and can damage the boiler if the ash becomes thick enough to collapse. In that case, it will endanger the boiler tubes of the power plant and damage the boiler, so it is necessary to stop the power plant operation.

The system for removing the ash accumulated on the boiler wall is a system called “Water Soot”, which sprays water from a device similar to a large water nozzle installed on the boiler wall. In the cleaning process, in order to remove the slag, water will be shot to a position on the other side of the boiler wall, where ash accumulates. This process occurs while the power plant is producing electricity (load-on) and to remove ash accumulated in the process of power generation. When spraying water to clean the furnace wall, the data from the sensor is used to identify the location or area where ash accumulates. This kind of sensor is called a slag deposition sensor. However, the sensors are expensive, and a large number of sensors need to be installed to cover the area of the boiler wall.  The traditional sensor installation will have certain risks in the process of installing the sensor on the boiler tube wall because it is necessary to cut and weld the boiler tube and then install the sensor on the boiler tube. The service life of the sensor is limited.