Arrival on site
With commercial and scheduling arrangements agreed, specialist machinery is brought to the Client’s site and positioned alongside the fired heater to be decoked in a manner agreed with Refinery Management.
Machine dimensions:
- length: 40 feet (12.20m)
- width: 8 feet (2.50 metres)
- height: 13 feet 4 inches (4.00 metres)
Machinery arrives fully resourced, including comprehensive accessories:
- minimum of 700 feet of hard and flexible connection tubing
- hammerlock couplings, with variety of connection fittings
- a wide range of cokebuster scraper pigs – all types
- hand tools and spare parts to meet all foreseeable eventualities
- safety equipment
- hand use lifting equipment
- purpose fabricated launchers of appropriate sizes
- water and electrical utility connectors – range of types
Connections to the furnace/fired heater/boiler
The initial set up procedure usually requires an on site crane. Although launchers are not heavy, they are not readily man-handleable. If connections are made to a high level, this can be achieved safely and quickly with mobile cranage.
On board water circuit connection tubing is used to connect the Double Pumping Unit simultaneously to two passes of the heater. A launcher of appropriate diameter size is attached to the inlet & outlet flanges of each pass. This establishes a water circuit between the Double Pumping Unit and the heater pass.
Note: two passes are connected to optimise time efficient simultaneous decoking.
All launcher receivers are fitted with an attached full bore valve which provides periodic isolation from the water circuit for the inspection and changing of scraper pigs during the decoking process. Launchers must always be fitted horizontally.
Water circuit tubes, flexible and rigid, are connected to launchers using quick assembly hammerlock couplings. Ideally, launchers should be connected to heater flanges allowing direct entry to the heater tube system – with a straight coupling, or through a swept elbow.
Utility connections
FUEL:- the Client is normally required to supply diesel fuel. For guidance, usage is not likely to exceed 10 gallons (40 litres) per hour.
WATER:- a connection is required for continuous supply of visibly clean water. Normally this can be taken from a locally positioned fire line. In certain cases demineralised water may be required.
ELECTRICAL:- although the SERIES 21 machines are able to run on generated power, a local connection is preferred. This may be 220v or 110v at 13-15 ampere.
The Pigging Operation
With a water circuit established, the decoking operation can commence. Operators will initially use hard foam pigs to confirm an unobstructed pass. After this, a selection of cokebuster pigs will be used in increasing dimensions to remove all contaminations existing inside the tube circuit.
All water is returned to the Pumping Unit clearly within the view of the Operators who have the facility to change return water to dirty or clean storage tanks.
Operators are able to track the progress of cokebuster pigs through the heater pass, and use accurate pressure differential signals to determine coke thickness and location. All removed coke is returned to the machine where it is collected through on-board filtration.