System and method for loading, storing and offloading natural gas from ships

A system for loading and storing CNG on board a ship and for unloading it therefrom, the system being situated on the ship and comprising:

• CNG loading facilities for loading CNG on board the ship;
• CNG storage facilities for storing the loaded CNG on board the ship at storage pressures and temperatures;
• and
• CNG unloading facilities for unloading the stored CNG to a delivery point, the delivery point requiring the stored CNG to be unloaded at delivery pressures and temperatures generally different from the storage pressures and temperatures, the CNG unloading facilities comprising:
• a CNG heater for heating to-be-unloaded CNG prior to unloading;
• a lamination valve for allowing the to-be-unloaded CNG to expand from the storage pressure to the delivery pressure prior to unloading;
• a compressor unit for compressing the to-be-unloaded CNG downstream of the CNG storage facilities prior to unloading;
• a compressor pressure control unit located downstream of the compressor unit;
• a separator unit located downstream of the CNG heater and upstream of the compressor unit;
• a separator flow control unit located downstream of the separator unit for separating liquid from CNG and upstream of the compressor unit;
• a feedback flow valve located downstream of the compressor pressure control unit;
• and
• a compressor controller programmed for operating the feedback flow valve so that unloaded CNG can be re-injected into the compressor unit before it is unloaded by the CNG unloading facilities,
• wherein the separator flow control unit and the compressor pressure control unit are each configured to provide information to the compressor controller.