🔍 Key Concepts

• Boiling point and cargo containment: How the boiling point of a liquefied gas affects whether it’s carried under pressure, refrigerated, or at ambient conditions. • Difference between LPG and LNG: Which gases can be kept liquid with pressure only, and which require very low temperatures. • Atmospheric pressure vs temperature control: What it means to carry a cargo at or near atmospheric pressure, and what must be done to its temperature to keep it liquid.

💭 Think About

• Compare the boiling point of methane (-161°C) with typical ambient temperatures on a ship. Could it stay liquid at normal ambient temperature, even if you applied reasonable pressure? • Think about which liquefied gases are called LNG (like methane) versus LPG (like propane and butane), and how each is usually transported. • Ask yourself: if a cargo boils (turns to gas) at a very low temperature, what must the ship do (pressure, temperature, or both) to keep it in liquid form during the voyage?

✅ Before You Answer

• Check if a cargo with a boiling point of -161°C can realistically be kept liquid at normal ambient temperatures, even under high pressure. • Review which containment systems are used for LNG versus LPG on gas carriers (fully pressurized, semi-pressurized/refrigerated, fully refrigerated). • Confirm whether “atmospheric pressure” in marine gas transport usually implies a need for very low temperature to maintain the liquid state.