Block & Bleed Valve for Chemical Injection Skid SLI

A custom compact double block and bleed valve is helping to reduce the size and weight of a groundbreaking skid produced for the Chevron Tahiti platform in the Gulf of Mexico. Built by Test Automation & Controls, the equipment is believed to be the largest chemical injection skid ever produced, and has been designed to operate at 1000bar to withstand the pressures required for operations in the Tahiti field's deep, sub-salt reservoirs. The integrated valve provides a 1000bar rated double block and bleed function. At this operating pressure, such valve configurations are usually constructed using discrete components — involving a large amount of space, extensive weight, and a large number of potential leak paths. The number of components is often made higher because the cone and thread interfaces used to make connections at these pressures are usually fitted with an additional anti- vibration accessory, to combat the common issue of vibration-induced problems associated with threaded connections. To simplify the project, an uprated version of the single-piece 700bar double block and bleed manifold was suggested, fitted with 1000bar rated MPI compression tube fittings.  The resulting manifold is estimated to have reduced the mounting space and weight budgets by around 50%, and replaces around nine individual components (three valves and six anti- vibration glands) — greatly reducing potential leak paths. "The size and weight reductions contributed by this manifold have helped to reduce the topside equipment budget, " says Kevin Burke of Parker Hannifin. "The manifold also helps to eliminate threaded connections, a common source of reliability problems."