Phase 1. Arrival:

Upon arrival, the trailer mounted Pumping Unit will be spotted in a position agreed to with Refinery Management.

Dimensions of the Pumping Unit:
-48' long -13'6" high -8'.6 wide
When the technicians have been cleared through site specific, hook-up to the furnace will begin.

The Unit arrives with all required equipment, including launchers, rigid & flexible 3" water piping complete with a comprehensive variety of couplings.

Phase: #1
 
OPERATION
RESPONSIBILITY
Duration (typical)
1 Spotting the Pumping Unit on site HKV one hour
2 Refinery Safety Procedures (typical) REFINERY two hours



Phase 2. Furnace Hook-up:

During the set-up procedure, connection is made to a pair of passes (coils) with flow & return piping; there are four separate piping links between the furnace and the Double Pumping Unit.

300# flanges at all pass access points require to be cleared for the connection of the special launcher/receiver units. These are always set horizontally. Launcher/receivers are complete with a full port ball valve and may require a refinery supplied crane to lift into position.

The launcher/receiver must be positioned to be safely accessible and the end access doors can be freely operated. It is not mandatory for the launcher/receivers to be at grade however such an arrangement is usually safer and can also facilitate a smoother & quicker hook-up.

On each launcher/receiver is a hammerlock coupling for attaching the water piping. This piping, maybe flexible and or rigid, and will run horizontally & Double Pumping Unit.

Phase: #2
 
OPERATION
RESPONSIBILITY
Duration (usual)
1 Laucher/receiver installation (typically 4 units) HKV/REFINERY 2 - 4 hours
2 Connection of water circuit piping HKV With same period

Phase 3. Utilities:

a.-electricity: Two 20 amp - 110v HKV circuits will be connected to a locally available electrical outlet. This is preferred as 'clean' power for operating the onboard computerized tracking systems.
b.-fuel: Diesel fuel to be supplied by the Refinery as required.
c.-water: A connection is required from a nearby refinery fire hydrant.

Phase: #3

Prior to the decoking operation, sufficient water is required to fill the passes of the furnace and the clean water tank of the Double Pumping Unit. This is normally a quantity not exceeding 7,000 gallons. When the pigging operation commences, the initial cleaning stages will require the highest amount of water. The rate of water required is dependant upon a number of indeterminable factors; it is unlikely to exceed 3,000 gallons per hour, and will decrease as the furnace tubes become clean.

 
OPERATION
RESPONSIBILITY
Duration (typical)
1 Installation of electrical connection REFINERY -
2 Water supply connection HKV/REFINERY -
3 Provision of diesel fuel REFINERY -
4 Connection for dirty water overflow to sewer HKV -

Phase 4. The pigging operation:

A full port ball valve separates each launcher/receiver from the passes. By the operation of these valves the launcher/receivers can be isolated from the system for the loading, recovery and changing of pigs. Once the furnace tubes are filled, the technicians circulate water only, for the purpose of removing remaining hydrocarbons and loose debris. The decoking process starts with a foam pig launched into a pass and propelled through, to be received at the corresponding pass outlet and or inlet. After inspecting the condition of the recovered special density foam pig, a decoke pig is selected and launched to clean a chosen diameter of the tubing within that pass or coil.

During the procedure the pigs are increased in size incrementally and different types of the 'family' of 'HKS' pigs may be selected. The specialized experience and continuous intense training of the technicians is a key factor within the core of the process. Before the technicians can confirm the completion of cleaning in a chosen pass, an oversized pig is used in an effort to compensate for any distortion or ovality which may exist in the furnace tube after previous uses of steam air decoking. The final runs in any given pass are made using an oversize 'silica' type abrasive coated foam pig for the purpose of polishing away any remaining isolated patches of coke or inorganic deposits.

The loading of each pig is carefully recorded and its passage through the furnace is monitored by a computer in the Pumping Unit Control Room. Experienced interpretation of these recordings provides each technician with the facility to study and record pressure and flow fluctuations returned by each pig as it decokes the tubes. Technicians can control the speed, direction, pressure and volume governing a pig's progress through the tubes. The Pumping Unit is designed with reverse flow for pigs to be bi-directional.

Upon the completion of a pair of passes or coils which are being simultaneously decoked, launcher/receivers are uncoupled without delay (crane maybe required). At this point, passes are drained using a method previously agreed to with Refinery Engineers. In the case of vertical furnace tubes, a compressed air purge maybe required to remove all remaining water.
In order to achieve the best time frame advantage, full use is made of the Double Pumping Unit where experienced and trained TECHNICIANS are able to co-ordinate decoking tactics from side by side computer controlled consoles. In this way, two passes or coils are decoked simultaneously, efficiently and thoroughly.

Safety note: 'HKS' pigs are tracked during their travel through the furnace tubes by the monitoring of pressure resistance differentials. In the unlikely event of a breach in the integrity of the furnace tubes, the technicians would be instantly aware of such a change and has the facility to switch to zero pressure and volume for investigations In a passive environment. All Pumping Units have automatic engine shut-down to provide for standard Refinery requirements in the event of airborne gas leakage, or other emergency.All Pumping Units have diesel engine spark arrestors as standard equipment.All personnel are trained to prevailing regional and national standards.



Phase: #4
 
OPERATION
RESPONSIBILITY
Duration (standard)
1 Pigging operation - continuous HKV -
2 Collection of coke & inorganic contaminants HKV -
3 Air purge (where necessary) HKV/REFINERY -

Phase 5. Effluent:

During the course of the decoke dirty returns containing coke, hydrocarbons and 'black water' will be received in the Double Pumping Unit's effluent tank. Large sizes of coke and removed contaminants will be held in the stainless steel catch baskets; suspended solids in the form of 'fines' will settle in the effluent tank and will form a sludge in the bottom. As the tank fills during the process, discoloured water will require disposal by the refinery, this is normally done by direct draining into the refinery sewer system or by using a vacuum truck.
 
Phase 6. Completion:

At the end of the decoking operation, with all passes/coils cleaned and drained, all equipment is disconnected and mounted back onto the road going Pumping Unit. All equipment and personnel are then removed from site, leaving the area clean and clear.

Phase: #6
 
OPERATION
RESPONSIBILITY
Duration (standard)
1 Disconnection and demobilization of equipment REFINERY/HKV 2-4 hours

STAINLESS STEEL TUBING PASSIVATION

For the protection of furnace tubing with Stainless Steel content, it is proposed to use clean water with a 2% sodium carbonate additive. It is for the Refinery Technical Department to decide if fireline water is acceptable for this purpose. Occasionally a Refinery will permit the use of this water only until the inner tube surface is exposed. Demin water is usually required and this will be supplied by the Refinery during appropriate stages of the decoking/pigging operation.Once brought out of service and cleared of hydrocarbons, the furnace tubing should be held in a nitrogen purge (by the Refinery). At the moment of attaching HKS Pigging launcher/receivers, the nitrogen can be placed under slight pressure to prevent air entry into the tubing. Once the launcher/receivers are connected, the furnace tubing can remain sealed by the closing of the HKS Pigging full bore ball valves which are attached to each launcher/receiver.

For the commencement of decoking operations, the furnace tubing must first be filled with water (with added soda ash). The Pumper unit clean tanks contain approximately 11,4000 Liters each, these two tanks will be filled with fireline (or demin) water and the sodium carbonate can be added and the percentage content tested.

It should be understood that HKV Pigging water connection tubes will contain air. These are the tubes, rigid and flexible, which are laid between the two Pumping units and the eight furnace access flanges. Each of the launcher/receivers is fitted with an air valve. These can be systematically opened as the water is slowly pumped from the Pumping unit feed tanks. This operation will purge all the air from connection tubes and launcher/receivers, while preventing air entry into the furnace tubing by means of the closed main ball valve.Once purged of air, the main valves will be opened to allow the flooding of furnace tubes in all four passes. Contained nitrogen will be expelled and full circulations established. With the commencement of decoking, al contaminations on the tube surfaces will be removed, with coke and discolored water being collected in the pumper unit dirty tanks. As this contaminated water is dumped, so the clean tanks will require continuous refilling. It will be necessary to maintain regular monitoring to ensure the correct percentage of soda additive.Collected coke, inorganics, and discolored water will collect in the pumper unit dirty tanks, with the overflow permitted to run to drain. Collected solids will be available for analysis and disposal by the Refinery under local duties of care regulations.

Water Supply

The largest quantity, of water will be required for the initial filling of furnace tubes and the early stages of decoking where most of the water will become contaminated by removed coke and inorganic material. The total decoking operation is likely to take approximately 30 hours.