Hydrate prevention is used to prevent hydrates from forming.
Operating conditions must remain out of the hydrate-formation zone
Hydrate point must be maintained below the operating conditions of the system
Two common methods of hydrate-formation prevention are:
Temperature control
An indirect heater is used to heat gas to maintain temperatures above that of the hydrate formation.
It consists of an atmospheric vessel containing a fire tube (usually fired by gas, steam, or heating oil) and a coil (designed to withstand SITP) that is heated by the intermediate fluid (usually water) and the fluid is heated.
The fire tube and coil are immersed in a heat transfer fluid (normally water), and heat is transferred to the fluid in the coil.
Chemical injection
Hydrate inhibitors are used to lower the hydrate formation temperature of the gas.
Methanol and ethylene glycol are the most commonly used inhibitors.
Recovery and regeneration steps are used in all continuous glycol injection projects and in several large-capacity methanol injection units.