Boiler Chemicals (Waterside)
CHEMICALS TREATMENT ON BOILER SYSTEM
A boiler is an apparatus to heat water by harnessing the heat from fuel combustion. The heat is then channeled to water inside it to produce steam (water vapor that has high temperatures). The steam produced is then used to heat a system or to power a motor that will produce a different form of energy such as electrical energy in a steam-powered electric generator.
Feedwater that is used in the boiler often contains impurities that impair the performance & efficiency of the boiler system. Therefore, feed water needs to be processed so that the impurity diminishes, and the potential of the problems arising in the boiler can be prevented.
Although the raw water has been processed, potential problems still exist because the impurity could not be removed completely from the water. These potential problems will remain even though it has been decreased. Chemicals can be used to overcome the problems caused by impurity that persists in the water.
Treatment program requires a relatively small percentage of the overall operational cost of the boiler. On the other hand, bad treatment performance will cause a domino effect that increases the boiler's operational and maintenance cost. For the best result, the right dosage of chemicals should be injected continuously to treat the internal parts. These chemicals can be injected directly into the feed water tank or water transfer path. Some chemicals can be mixed and used at the same time. The chemical is normally injected on a spot higher than the boiler circuit. For feeder chemical located under the feedwater pump, the pump must be adjusted to the boiler pressure.
Some problems that are caused by Impurities in Boiler
Scale is hardened mineral deposit that settles on the pipe or boiler walls. This solid buildup occurs as a result of the reaction between the impurities in the water and the surface of the tube metal. Because scale serves as an electrical insulator, it slows down the transfer of heat so that the efficiency is plummeting, and fuel consumption is increasing.
Even worse, it may cause more serious effects like overheating and corrosion on the boiler's tube. Corrosion is caused by dissolved oxygen in the feed water. This oxidation reaction is getting more aggressive when receiving heat energy resulting in corrosion on the metal surface. Damages due to corrosion can occur on drum boiler, header, and condensate tube.
Acid can also cause corrosion on the metal. Feedwater is called acidic when its pH is under 8.5. Alkali carbonate reacts to heat and pressure in the boiler and transformed to CO2 which will be swept along the produced water vapor. When the water vapor condenses, CO2 will be dissolved in water and form carbonic acid (H2CO3) that will directly reduce condensate water’s pH. This acid can damage the condensate tube.
Benefits of Chemical Treatment.
• Improving the boiler’s performance;
• Conserving fuel and having cheaper maintenance cost;
• Reducing engine downtime; and
• Protecting production asset from damages and improving its usability.