Creative Engineered Solutions for Subsea Developments

Detailed Sequence of Operation

A typical dryer cycle time takes approximately 20 minutes (12 minutes for medium pressure) with the two adsorption vessels on drying duty for ten minutes each.

Flow diagram

At the start of the cycle, both Inlet Valves V1 and V2 are open with exhaust valves V3 and V4 closed. After 20 seconds V2 will close, putting Adsorption Vessel 1 on drying duty. Twenty seconds later V4 will open, allowing the air in Adsorption Vessel 2 to vent to atmosphere via the silencer thereby starting the regeneration of Adsorption Vessel 2. Purge air now flows from the purge orifice down through Adsorption Vessel 2 and out through the purge valve V4 to the silencer.

At the end of the purge period (typically 3-4 minutes) purge valve 4 will close. Air continues to pass through the purge orifice into Adsorption Vessel 2 until it has returned to the original system pressure . Inlet valve V2 can now open, shortly followed by Inlet Valve V1 closing to bring Adsorption Vessel 2 onto drying duty.

Exhaust valve V3 will now open to start the regeneration of Adsorption Vessel 1. After the purge period is complete, purge valve V3 will close and the pressure will equalise between the Adsorption Vessels so that inlet valve V1 can again open to start the next cycle.