View
218
Download
0
Category
Preview:
Citation preview
Hydrates• The compounds formed by the interaction of water and
hydrocarbons at certain pressures and temperatures.They are crystalline substances
• Reaction with water
• Propane or Butane react with water and form hydrates
• block lines filters, pumps re-liquifaction plants.
• Can be prevented by inhibitors
.
Drying of Cargo Tanks
Why to Dry Tanks?
How can you dry Tanks?
Moisture/condensation will freeze
For Invar Membrane, corrosion may be caused by IG
Use of IG Generator delivering dry air
MAIB Tanker Awareness by WMA
Inert Gas Generator, can be used to deliver dry air (burner not used)
Dry Tanks later Inert Tanks
Water Content at Dew Point TemperatureDP Temp +40 = 52 g/m3
DP Temp +4 = 7 g/m345 g/m3 Removed
DP Temp -40 = 0.1 g/m3
6.9 g/m3 Removed
Lighter
Heavier
N
A
I
L
itrogen
ir
nert Gas
PG
Methane
Changing Atmospheres - Displacement
Methane @ -100°C = Air
Inerting Tanks then Pipelines
Why?
How?
To prevent formation of a flammable atmosphere (anywhere in the system) IGC Code Ch. 9
With IG Generator (typical - 14,000 m3/hr)
In line cooler/dryer
Oxygen < 2.0% by vol.
Dew Point < - 40°C
Always by Displacement (layer or piston method) in parallel
Inerting• By displacement method
• low speed of inert gas
• 135,000 m³
• IGG 11,000 m³/hr
• 1.25 atmosphere changes = 168,750 m³
• Total time 15hrs 20mins
• Gas oil consumption about 16 tonnes
• 1.5 atmosphere changes = 202,500 m³
• Total time 18hrs 25mins
• Gas oil consumption about 18 tonnes
• entering of IG on top or bottom of tank (depending of specific density)
Recommended