Hydrates in LPG Cargoes

This publication is a technical review of the processes and procedures commonly found in production, storage and transportation of LPG cargoes. It examines the presence of water in LPG cargoes, the formation of hydrates and methods for their elimination. Hydrate formation in cargo systems of refrigerated LPG carriers can damage pumps and other machinery and obstruct cargo handling. This publication, based on a review conducted for SIGTTO by Mr R C Gray of the Technology Department of British Shipbuilders, deals specifically with hydrates forming in commercially dry refrigerated LPG. It identifies the ways in which water can enter and remain within the cargo, leading to the formation of hydrates. It examines different methods to prevent ice and hydrate formation and outlines procedures for cargo tank sampling. The Appendices provide practical information on the propane-water system, use of LPG freeze valves and the addition of methanol as a treatment method.