AN APPARATUS FOR VENTING AN ANNULAR SPACE BETWEEN A LINER AND A PIPELINE OF A SUBSEA RISER

摘要

An apparatus for venting an annular space between a liner and a pipeline of a subsea riser (2) for conveying hydrocarbons, said apparatus comprising permeate recovery means for recovering permeate passing through the liner into said annular space. Preferably said permeate recovery means comprises a first- vent port (10) provided in a wall of the pipeline at or adjacent a lower region of the pipeline and communicating with a permeate recovery line (11) defining a flow path between said annular space and a permeate collection vessel (12). Preferably a one-way valve is associated with said permeate recovery line for preventing flow from said permeate recovery line (11) into said annular space.