FLUE GAS SYSTEMS (FGS)

These systems are generally used on crude oil tankships where a higher quality inert gas is not required for the unrefined cargo product. The gas in this case is available as a by-product of boiler combustion and is taken from the ships boiler uptake. Typically a range between 4% to 5% O₂ content with some soot content dependent upon flue gas quality.

A typical Flue Gas System as shown here includes six major component parts, each having special features.

Scrubber Tower*

Combining a high energy venturi scrubber with a packed tower scrubber enables high efficiency particulate removal, cool quenching, cleaning and final demisting of boiler flue gases.

Gas Fans

Single stage centrifugal inert gas fans are used. The fan impellers are dynamically balanced and manufactured in corrosion resistant material. The casings are internally glass flake coated to reduce maintenance.

Deck Water Seal

'Wet Type' design with an external seal pipe ensuring added safety. Water is displaced during normal gas flow forming a semi wet seal. Entrained water is expelled by swirling the gas in the vessel and passing it through an integral demister.

Pressure/Vacuum Breaker

Providing final protection by releasing excessive pressure or vacuum from the cargo tanks ensures that the tank design conditions cannot be exceeded. The design is totally fail-safe

Valves

Gas delivery and control valves are normally of the butterfly type with bonded rubber linings and corrosion resistant discs and shafts. Where remotely controlled, these valves use a double acting actuators. The boiler uptake valves are of the butterfly wafer pattern type suitable for high temperature with metal seating. These are normally pneumatically operated and fitted with limit switches for remote control and indications.

Control System

Utilises a programmable logic controller to give the required functions of control along with designated selective acceptance of alarms. The instrumentation and control panels are generally located in the engine room, cargo room and bridge. Customers special requirements can be incorporated.