Chemical treatment boiler feedwater is the process to treat feedwater chemically to be desired requirement of feedwater. Chemical treatment boiler feedwater should be performed to maintain steam boiler keep in highest efficiency. One way of chemical treatment boiler feedwater is by adding chemical injection such as sodium phosphate. This action is carried out to prevent deposit or crust formation and decrease level corrosion on the metal pressure part boiler.
The following below are advantages of chemical treatment boiler feedwater:
- Prevention of deposits formation
Water that contains high hardness, turbidity, silica and high solutes content tend to cause scaling, deposit or crust on the boiler pipes or tubes. Deposit or crust will form thin layer inside boiler tubes. This layer can reduce heat transfer process from metal tubes to boiler water inside it. So steam boiler need more combustion to heat boiler water, it means that need fuel addition to perform more combustion so it will decrease boiler efficiency.
- Decrease level corrosion
Metals will experience corrosion at low pH (pH < 7). Furthermore steam boiler must be injected by chemicals to raise pH feedwater before being used as boiler water or chemical can be injected to boiler water in steam drum in order to give effect to minimum corrosion.
The chemicals that is used to adjust pH feed water is sodium chloride. Other way to decrease pH in boiler is by inject other chemicals to bind the dissolved CO2 in the feed water because oxygen (O2) will result in depolarization cathode, so it causes corrosion. The chemical which is used to bind the dissolved oxygen is hydrazine (N2H4).