Without a reliable supply of coal, even the best of all power plants
couldn’t deliver the required energy. Reliable monitoring of the coal reserves is therefore absolutely essential. The coal is delivered by sea and unloaded into bunkers up to 30 m high. The coal is transported to these bunkers from the stockpiles of the power plant via conveyor belt systems above or below ground. From there, the coal has to be transported to the mills, where it is ground into a fine powder for subsequent combustion in the combustion chamber of the furnace. Reliable level sensors
are required everywhere to ensure uninterrupted charging of the combustion chamber and to prevent overfilling of the bunkers. Especially critical is the continuous monitoring of the minimum level in the coal dust silos, because an interruption of supply to the furnaces must be avoided at all costs.
The problem: The ambient conditions that prevail in coal bunkers are not the easiest to deal with – logically, all sensors quickly get covered with dust and dirt. At the power plant in Tanjung, too, the company was constantly struggling with a measuring point that was supposed to display the precise height and thus the quantity of the coal reserves. However, the opposite was the case: again and again the reading jumped to the 100% value, although the actual level was completely different, often being close to zero. It was not only the dusty environment and the loud filling noises that caused problems for the measuring instrument, but also the typical bulk material distribution in the bunkers.