Q9
Make a diagrammatic sketch of a jacket cooling water system as applied to a group of medium speed auxiliary diesel engines. Indicate the temperatures and pressures in the system. Describe in particular, the flow of water from entry to the engine, to the outlet from the engine and sketch the more important joints in the system (16)
Cooling system & FWG
10 marks
May 2024
Answering keywords
Q1
(a) Sketch a main engine jacket water cooling system (8) (b) State why chemical treatment of such systems is necessary (4) (c) What tests are carried out to ascertain the level of the concentration of the chemicals in the jacket cooling water system? (4)
Cooling system & FWG
10 marks
Jan 2024
Aug 2023
(a)
(b) The Necessity of Chemical Treatment in the Cooling Water System:
- Corrosion Prevention: Chemical treatment with inhibitors helps prevent corrosion of metal components in the cooling system, which can lead to costly damage and leaks.
- Sludge Formation Control: Treatment chemicals prevent the formation of sludge and deposits in the system, which can reduce heat transfer efficiency and clog pipes.
- Scale Deposit Prevention: Proper chemical treatment inhibits scale deposits that can accumulate on heat exchange surfaces, reducing heat transfer and efficiency.
- pH Control: Chemical treatment helps maintain the pH of the cooling water within a specific range, preventing acidic or alkaline conditions that can contribute to corrosion and scaling.
(c) Tests for Monitoring Chemical Concentration in the Jacket Cooling Water System:
- pH Measurement: Regular monitoring and adjustment of pH levels within the recommended range to prevent corrosion and scaling.
- Chloride Ion Concentration: Periodic testing to ensure chloride ion concentration is within acceptable limits, as excessive chloride ions can lead to corrosion. Chloride content not to exceed 50 ppm
- Total Dissolved Solids (TDS) Measurement: Measurement of TDS levels to control the concentration of dissolved solids in the cooling water, which can impact scale formation.
- Hardness Testing: Regular testing for water hardness (calcium and magnesium ions) to determine the need for water softening treatments to prevent scale formation.
- Alkalinity Testing: Measurement of alkalinity to maintain the water’s buffering capacity for effective pH control and corrosion prevention. pH valve should be 8.5 to 10 at 20°c.
UKM Tuticorin 