Q2. With reference to the carriage and pumping of liquefied gas cargo:
A. Sketch a suitable pumping system labelling the component parts;
i) Why submerged hydraulically driven pumps are not used;
ii) How overheating of pump drive shaft bearings is avoided;
C. State, how the risk of fire and explosion in cargo tanks is obviated both in the loaded and discharged condition.
Q1. With reference to membrane tanks for the carriage of liquefied gas at very low temperatures. A. Describe with a sketch one method of building up the insulation; B. State which alloy is used for the membrane and the reason; C. Explain why a secondary barrier is installed. i) Longitudinally; ii) Transversely
Q2. (a) Define critical temperature and boiling point and hence show how some liquefied gases may be transported fully pressurized, whilst others need to be carried fully refrigerated.
(b) State the basic differences in construction of fully pressurized and fully refrigerated systems for the carriage of liquefied gas at sea.
(c) Compare the membrane tank and independent tank systems of construction.
(a) Define critical temperature and boiling point and hence show how some liquefied gases may be transported fully pressurized, whilst others need to be carried fully refrigerated.