VIDEOS

DEHA Test





HYDRATE ALKALINITY





Condensate pH





Phosphate Test





NEUTRALIZED CONDUCTIVITY

PROCEDURES

TEST PROCEDURES

BEFORE TEST

• Read MSDS
• Put safety equipment
• Ensure the boiler water is in room temperature( 25 degree celcius)
• Filter the boiler water if there is any debris or solids.
  

DURING TEST

DEHA TEST

• Fill the sample cup to the 25ml mark with feedwater sample
• Add 2 drops of activator solution. Stir gently with the tip of an ampoule from the DREWPLEX OX corrosion inhibitor ampoule test kit to mix the content of the sample cup.
• Immediately snap the tip of the ampoule by pressing the ampoule against the side of the sample cup. The sample will fill the ampoule and begin to mix with the reagent, leaving a small bubble to facilitate the mixing.
• Remove the ampoule from the cup. Mix the contents of the ampoule by inverting it several times, allowing the small bubble to travel from end to end each time
• Wipe all liquid from the exterior of the ampoule and WAIT EXACTLY 10 MINUTES for full color development
• When using the comparator, be sure it is illuminated by white light directly above the comparator. The filled DEHA ampoule should be place between the color standard for viewing. It is important that DEHA ampoule be compared by placing it on the both sides of the standard tube before concluding that it is darker, lighter or equal to the standard
• Record the results on the onboard graphing log and adjust the drewplex ox inhibitor dosage as necessary

HYDRATE ALKALINITY

• Rinse and fill the plastic titration vial to the line( 12ml) with the cooled boiler water sample
• Pipette 2 ml of Barium Chloride 10% into the vial and swirl to mix
• Add 2 drops of Phenolphthalein indicator and swirl. If sample does not turn pink, the hydrate alkalinity level is zero. Record zero on the onboard graphing log and adjust dosage to increase hydrate alkalinity. If the the sample turns pink, counting the drop, add sulfuric acid N/10 until the sample turn colorless( disregard the eventual reappearance of the pink color). Swirl the vial between drops.
• Calculate the hydrate alkalinity concentration as follows: Number of drops of sulfuric acid N/5= ppm Hydrate Alkalinity as OH.

Record the hydrate alkalinity level on the onboard graphing log. Make dosage adjustments as needed.


NEUTRAULIZED CONDUCTIVITY

• Press the power switch and allow the meter to warm up for 1 minute. Connect the black band( Outer scale) conductivity cell to the meter. Add 2 drops of the Phenolphthalein indicator to the cooled boiler water sample and stir
• If teh sample turns pink, add gallic acid while stirring until the pink color disappears.( This neutralizes the sample)
• Submerge the cell in the neutralized boiler water sample to a depth to cover the vent holes in the cell. Agitate the cell to vent all trapped bubbles from the cell interior. Measure the temperature of the sample and set the temperature knob to this value
• Rotate the conductivity knob until both red and green indicator lamps are lighted at the same time. Read the conductivity value on the appropriate scale. Record the test result on the onboard graphing log and refer to chart at right after blowdown.
• Remove teh cell from the boiler water sample and rinse it with clean water. Press the power switch to shut off the meter.

CONDENSATE pH

• Obtain a 12ml samle and test immediately
• Add 2-3 drops Phenolphthalein
• If pink color develops, add sulfuric acid n/10 drop wise until sample turns colorless
• Record result on the onboard graphing log

PHOSPHATE TEST

• Fill the sample cup to the 25ml mark with the sample
• Place the boiler phosphate ampoule's tapered tip into one of the four depression in the bottom of the sample cup. Snap the tip by squeezing the ampoule toward the side of the cup. The sample will fill the ampoule and begin to mix with the reagent
• Remove boiler phosphate ampoule from the cup. Mix the content of the ampoule by inverting it several times allowing the bubble to travel from end to end each time.
• Wipe all liquid from the exterior of the ampoule and WAIT FOR 5 MINUTES for full color development
  
• When using the comparator, be sure it is illuminated by white light directly above the comparator. The filled boiler phosphate ampoule should be placed between the color standards for viewing. It is important that the ampoule be compared by placing it on both sides of the standard tube before concluding that it is darker, lighter or equal to the standard.

AFTER THE TEST BEING DONE

• Dispose the chemical in designated areas and wash the apparatus with water
• Ensure all the chemical are lid tightly and keep away for direct sunlight
• Put back the housekeeping and huosekeeping
  

CORROSION OF BOILER TUBES

CORROSION AND SCALING

Corrosion and scaling will occur when boiler water treatment does not practice. This will reduce the efficiency of the boiler and the performance is not is its maximal. The deposits will clog up the tubes and hence, this will increase the pressure in the tubes and in the end, the tubes will bust or leak.

These are the possible reasons that cause the tubes corrosion and scaling

TUBES OVERHEATED







Indication of tubes overheated-the colour of water tube. The tubes is dark in color at one section and another is light in color at another section.Hence, This indicate that the tubes at overheating.












The water tube is bulging. This shows the tube is overheating






LEAKING







This indicates that there is leaking to the boiler tubes. White deposit appeared at the bottom end of the tubes. It is a salt( SODIUM CARBONATE).







CAUSTIC CORROSION



The term of caustic gouging and ductile gouging refer to the corrosive interaction of sufficiently concentrated sodium hydroxide with the metal to produce distinct hemispherical or elliptical depressions. The depressions may be filled with dense corrosion products that sometime contain sparkling crystals of magnetite. At times, a crust of hard deposits and corrosion products containing magnetite crystals will surround and overlie the attacked region. The affected metal surface generally has a smooth, rolling contour.


This why boiler water treatment is so important so that it could get rid of sodium hydroxide in the feed water


OXYGEN CORROSION

One of the most frequently encountered corrosion problems results from exposure of boiler metal to dissolved oxygen. Since the oxides of iron are iron's natural, stable state, steel will spontaneously revert to this form if conditions are thermodynamically favorable. Generally, conditions are favorable if steel that is not covered by the protective form of iron oxide is exposed to water containing oxygen.The following reaction occurs:

2FE+H2O+O2=> FE2O3+2H

The fracture sites furnish anodic regions where oxygen containing moisture can react with bare, unprotected metal. The result may be deep, distinct, alomost hemispherical pits, which may be covered at times with caps of corrosion products.

HYDROGEN DAMAGE

Hydrogen damage may occur where corrosion reactions result in the production of atomic hydrogen. Damage may result from a high-pH corrosion reaction or low pH corrosion reaction. Damage resulting from a high-pH is simply caustic corrosion.

Concentrated sodium hydroxide dissolves the magnetic iron oxide according to the following reaction:

4NAOH+FE3O4=> 2NAFEO2+NA2FEO2+2H2O

With the protective covering destroyed, water is then able to react directly with iron to evolve atomic hydrogen:

3FE+4H2O=>FE3O4+8H

The sodium hydroxide itself may also react with the iron to produce hydrogen:

FE+2NAOH=>NA2FEO2+2H

If atomic hydrogen is liberated, it is capable of diffusing into the steel. Some of this diffused atomic hydrogen will combine t grain boundaries or inclusions in the metal to produce molecular hydrogen, or will react with iron carbides in the metal to produce methane.

FE2C+4H=> CH4+3FE

As microcracks accumulate, tube strength diminishes until stresses imposed by boiler pressure exceed the tensile strength of the remaining, intact metal. At this point a thick-walled, longitudianl burst may occur. Depending on the extent of hydrogen damage, a large, rectangular section of the wall frequently will be blown out, producing a gaping hole.

SAFETY

SAFETY


Before Testing

• Read MSDS before start working on the test
  

• Samples must be cooled 25 degree Celsius( room temperature) by collecting through a sample cooler for safety and to prevent flashing which concentrates the sample.
• Sample must be filtered if the the sample is coloured or turbid.
  

MSDS( MATERIAL SAFETY DATA SHEET)

• Form containing data regarding the properties of a particular substance

• To provide workers and emergency personnel with procedures for handling or working with that substance in a safe manner and includes information such as physical data ( melting point, flash point, boiling, etc), toxicity, health hazard, first aid, reactivity, storage, disposal, protective equipment and spill handling procedures.

Make sure before doing any tests, please ensure that MSDS has been read and understand.

EXAMPLE OF MSDS

1. Phenolphthalein
2. Sulfuric Acid
3. Barium Chloride
   

PERSONAL PROTECTION EQUIPMENT( PPE)

• Ensure you are wearing face shield to prevent any chemical entering your eyes, skin or the mouth.
• Wear long gloves that covered the elbow to prevent any corrosive chemical contact to the skin which could cause severe irritation on the skin.
• Safety boots must be wear at all times to prevent any heavy object that could injure the the feet.
• Wear appropriate attire
• When emergency, please following the procedures in the MSDS
• If medical attention is needed, please send the victim to the hospital as soon as possible
• Ensure there is no flammable item with you all times such lighter

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.