Online measurement of deposits in high temperature furnaces/ power plant boilers

The Institute of Combustion and Power Plant Technology (IFK) of the University of Stuttgart has developed a measuring device for use in coal power plants. The device allows for permanent monitoring of the conditions inside the boiler, particularly of soot deposition.Besides determining the deposition rate inside the boiler, growth characteristics, adhesion, ash qualities and waste disposal behavior with deposit as well as the extent to which these can be cleaned using soot blowers can be judged. Thus, the measuring device can indicate potential for optimization, e.g. of coal compositon in the fuel feed.
The prototype has been tested successfully.

Deposits and combustion residues in power plant boilers reduce the efficiency of coal-fired power plants, which still account for a large share of the base-load supply in generating electricity.
The invention discussed here allows for the deposition rate to be determined even in high-temperature furnaces in real time for the first time. Besides determining the deposition rate inside the boiler, growth characteristics, adhesion, ash qualities and waste disposal behavior with deposit as well as the extent to which these can be cleaned using soot blowers can be judged with the help of the new invention.

In actual practice, depositions have been removed from power plant boilers by using probes; however the deposition rate (the amount of deposit on a defined area per time) cannot be determined that accurately. For this reason, the boilers are cleaned at the end of the combustion chamber in certain intervals after a rise in temperature. Nevertheless, this procedure reduces the efficiency of the boiler system in the same way as belated cleaning because energy is usually expended unnecessarily for cleaning.

The Institute of Combustion and Power Plant Technology (IFK) of the University of Stuttgart has developed a measuring device for use in online deposition measurement in high-temperature furnaces which allows for permanent monitoring of the conditions inside the boiler and provides information about the deposition rate in conjunction with computer analysis.
The device can be put to mobile use or be permanently installed. In this case, the heat-resistant ceramic rod of the measuring device is inserted into the boiler from the outside at multiple measurement points. Different deposits then settle on it during operation. Because the rod is linked to a measurement cell located outside the boiler, the amount of the deposit can be measured in real time and in high resolution (1/100 g of the weight mass, for example). The computer system connected to it calculates the deposition rate based on this measurement and can even initiate cleaning of the boiler by turning on soot blowers in the areas inside the boiler where the measurement shows an excessively high deposition rate, for example.
The entire measurement system is designed in such a way that an extremely flexible and easy adjustment of the position can be made in the horizontal and vertical direction. In fact, even the length of the probe can be adjusted.

• Permanent monitoring of a power plant boiler, particularly with coal combustion
• Measurement in high resolution during operation and action can be taken very swiftly in a targeted manner
• Insensitive even with high temperatures inside the boiler
• Fully automatic recording of deposits possible – also as a function of time
• The impact of the soot blower on the cleanability of deposits can be tracked

Online measurement of deposits in high temperature furnaces/ power plant boilers.