Boiler water test on ship. Boiler water test is a routine procedure that ensures the quality and safety of boiler water on board ship. Boiler water test can detect various impurities and contaminants that may affect the performance and efficiency of the boiler system. Boiler water test can also prevent corrosion, scaling and foaming problems that may damage the boiler components and cause operational issues.
Boiler water test on ship
There are different types of boiler water tests carried on marine boiler, depending on the purpose and frequency of testing. Some of the common boiler water tests are:
– Chloride test: This test measures the concentration of chloride ions in boiler water, which can indicate the presence of seawater contamination. Chloride ions can cause pitting corrosion and increase the conductivity of boiler water. The acceptable limit of chloride ions in boiler water is 100 ppm for low pressure boilers and 50 ppm for high pressure boilers. The test is performed by adding silver nitrate solution to a sample of boiler water and observing the formation of white precipitate. The amount of silver nitrate solution used is proportional to the chloride concentration.
– Excess phosphate test: This test measures the excess amount of phosphate ions in boiler water, which can indicate the effectiveness of phosphate treatment. Phosphate treatment is a chemical method to prevent scaling and corrosion by forming a protective layer of insoluble phosphate compounds on the boiler surfaces. The excess phosphate ions in boiler water should be between 20 to 40 ppm for low pressure boilers and 10 to 20 ppm for high pressure boilers. The test is performed by adding starch indicator and sulphuric acid to a sample of boiler water and titrating with ammonium molybdate solution until a blue color appears. The amount of ammonium molybdate solution used is proportional to the excess phosphate concentration.
– Total dissolved solid test (Conductivity test): This test measures the total amount of dissolved solids in boiler water, which can indicate the degree of concentration and purity of boiler water. Dissolved solids can cause scaling, foaming and carryover problems that may reduce the heat transfer efficiency and increase the fuel consumption. The acceptable limit of total dissolved solids in boiler water is 3500 ppm for low pressure boilers and 2500 ppm for high pressure boilers. The test is performed by measuring the electrical conductivity of a sample of boiler water using a conductivity meter. The conductivity value is proportional to the total dissolved solid concentration.
– pH value test: This test measures the acidity or alkalinity of boiler water, which can indicate the potential for corrosion or scaling problems. The pH value of boiler water should be maintained between 10.5 to 11.5 for low pressure boilers and 9.5 to 10.5 for high pressure boilers. The test is performed by using a pH meter or a pH indicator paper to measure the pH value of a sample of boiler water.
– Hydrazine test: This test measures the concentration of hydrazine in boiler water, which can indicate the effectiveness of oxygen scavenging treatment. Oxygen scavenging treatment is a chemical method to prevent corrosion by removing dissolved oxygen from boiler water using hydrazine or other reducing agents. The concentration of hydrazine in boiler water should be between 0.1 to 0.2 ppm for low pressure boilers and 0.05 to 0.1 ppm for high pressure boilers. The test is performed by adding p-dimethylaminobenzaldehyde solution and hydrochloric acid to a sample of boiler water and observing the formation of yellow color. The intensity of yellow color is proportional to the hydrazine concentration.
Boiler water test is an important procedure that should be carried out regularly and accurately on-board ship. Boiler water test can help to maintain the quality and safety of boiler water, optimize the performance and efficiency of boiler system, prevent corrosion, scaling and foaming problems, and extend the service life of boiler components.
