INTRODUCTION

INTRODUCTION

The objective of this "Boiler Feed water treatment blog" is to create it as a learning and teaching aid for both the lecturer and student in Singapore Maritime Academy. The blog contains the important aspect of boiler feed water treatment. With the help of our supervisor, Mr Premanathan, and Boiler technician, Mr Robert, our team have access to the boiler house and managed to experience the boiler water treatment kit.

What is Boiler Feed Water Treatment?



Proper treatment of boiler feed water is an important part of operating and maintaining a boiler system. As steam is produced, dissolved solids become concentrated and form deposits inside the boiler. This leads to poor heat transfer and reduces the efficiency of the boiler. Dissolved gases such as oxygen and carbon dioxide will react with the metals in the boiler system and lead to boiler corrosion. In order to protect the boiler from these contaminants, they should be controlled or removed, trough external or internal treatment.

Purpose of treatment and conditioning of feed water

1. Continuous heat exchange
2. Corrosion protection
3. Production of high quality steam

2 Types of treatment

EXTERNAL TREATMENT

External treatment is the reduction or removal of impurities from water outside the boiler. In general, external treatment is used when the amount of one or more of the feed water impurities is too high to be tolerated by the boiler system in question. There are many types of external treatment such as softening, evaporation, dearation, membrane contractors etc which can be used to tailor make feed water for the particular system.

INTERNAL TREATMENT

Internal treatment is the conditioning of impurities within the boiler system. The reactions occur either in the feed lines or in the boiler proper. Internal treatment may be used alone or in conjunction with external treatment. Its purpose is to properly react with feed water hardness, condition sludge, scavenge oxygen and prevent boiler water foaming.

Standard Boiler Feed Water Testing Program



HYDRATE ALKALINITY: Tested to monitor the amount of hydroxide alkalinity in the system. Caustic adjusts the boiler water pH and is involved in the reaction with phosphate to produce non adherent sludges.




NEUTRALIZED CONDUCTIVITY: Tested to control blowdown and measure the ability of a solution to conduct an electrical current. The boiler water sample must be neutralized to avoid excess conductivity measurement from hydroxide ions or alkaline salts.


PHOSPHATE: Tested to ensure that the treament is being dosed in sufficient quantities to react with incoming hardness and provide a safety reserve. The boiler water sample should be filtered before testing.



CONDENSATE pH: Tested periodically for reference purposes. A slightly alkaline pH minimizes corrosion of non-ferrous metals.

HYDRAZINE OR DEHA: Tested to ensure that there is a reserve to react with any oxygen which may enter the system, thus minimizing corrosion from oxygen.