How is the cool down of cargo tanks done?
Cool down is an operation to pre-cool cargo tanks and lines required before taking on cryogenic LNG. Cargo tank cool down is carried out by spraying LNG through the spray nozzles of each cargo tank, using LNG received from the shore terminal.
What is gas up cool down?
The gassing up and cooling down is a specialized service to bring the storage tanks on LNG carriers, after dry-docking, to natural environment and later cool it down to cryogenic temperature (minus 160 degrees Celsius) before loading its next cargo.
How do I cool down my cryogenic tank?
ISO Cryogenic tank container cool down is carried out by spraying nitrogen through the spray nozzles of each tank. The cool down operation from an ambient temperature to a planned temperature, is called ‘initial cool down’ and is to be differentiated from an ordinary cool down operation carried out during transit.
What is the purpose of cooling down cargo tanks prior loading?
– Cooling down – In order to avoid any damage to cargo tanks and piping due to thermal shock as well as to reduce the generation of boil-off gases (BOG) during loading operations, cargo tanks and piping are gradually cooled down.
What is the average recommended cooling down rate for cargo tank?
Test results demonstrate that tank cool-down rates of 4 to 5 oC/per hour can be maintained such that tank temperatures can be reduced from +30 to -130 oC within 37 hours.
Does LNG have to be kept cold?
Because of large volumes it is not practical to store natural gas, as a gas, near atmospheric pressure. However, when liquefied, it can be stored in a volume 1/600th as large. This is a practical way to store it but the gas must be kept at −260 °F (−162 °C).
What is gas up LNG?
During gassing up, the inert gas in the cargo tanks is replaced with warm LNG vapor. This is done to remove carbon dioxide and to complete drying of the tanks. The LNG vapour is lighter than the inert gas, which allows the inert gases in the cargo tank to be exhausted up the tank filling line to the liquid header.
Is hexane in natural gas?
n-Hexane is a minor constituent of crude oil and natural gas. Its inclusion in a variety of petroleum products is a consequence of refining operations that separate hydrocarbons within specific ranges of boiling points for such uses as heating oils or automotive fuels.
What is the average recommended cooling down rate for cargo tanks?