On-line Furnace Cleaning

ProDecon® have formed and agreement with Polarchem® to provide services in online furnace and boiler cleaning using their cutting edge technology.

Combustion side fouling of heat transfer surfaces occurs as a result of incomplete combustion which leads to the formation of carbon deposits. Some degree of incomplete combustion is inevitable no matter what type of fuel is being used (coal, heavy residual oil or gas).

Thermal cracking of the fuel is taking place in the combustion chamber because the fuel in the form of fine particles is exposed to high temperatures without adequate air. Cracking in vapour phase results in relatively softer carbonaceous deposits like soot. Cracking in liquid phase results in more sticky carbonaceous deposits. These deposits adhere to heat transfer surfaces especially at areas with flow constrictions. Apart from the unburnt carbon, sulphates and vanadates are other common substances that are found in fouling deposits.

Polarchem chemistry contains products which react with the majority of deposits. Injected online into the periphery of the flame the chemistry makes the deposits friable, dry and very easy to remove. The reaction also prevents the formation of sulphuric acid minimising the risk of corrosion. The process has zero interaction with the combustion process and causes no damage to the refractory or thermo-couples.

The location of the fouling can be determined by observing the bridge walls, the convection outlet and stack temperatures, the pressure drop across convection areas and across air heaters. The improvements in efficiency are quickly evident and regular use of Polarchem can significantly extend the run time and negate the need for water washing during shutdown.

The process can be applied to all types of box or cylindrical furnaces, with natural or forced draught, firing fuel oil alone or in combination with gas. Applied as a one off solution for performance restoration or as part of a continued preventative maintenance programme the Polarchem process reduces fuel consumption, corrosion, air pollution, soot blowing and increases the intervals between shutdown.

Tube Walls Before Cleaning

Tube Walls After Cleaning

Manual injection for one of performance restoration

Automatic injection for preventative maintenance