Tank Cleaning
Denholm MacNamee provide a unique process, utilising specialised equipment, which allows for the Safe, efficient and cost effective cleaning of large diameter crude oil storage tanks. This process is carried out in a “Non-Intrusive” Environment avoiding the normal requirement for Manned Entry.
The main benefits from this process are:
- Separation of Hydrocarbons from sands & solids that are present in the tank.
- Effective recovery of Hydrocarbons (cost return)
- Capability of handling solids within the sand & sludge (<35mm)
- Introduction of specialist chemistry to address the presence of:
- H²S (Hydrogen Sulphide)
- Pyrophoric Iron Sulphide
- Benzene
- LEL
This system has been designed and developed as a first stage option for the cleaning of large storage tanks where the level of liquid or sludge prevents the safe removal of man-way doors. The number of Tank-sweep nozzles required will depend on the diameter of the tank to be cleaned, typically 2assemblies shall be required for tanks up to 65 metres in diameter, with 3 or 4 being required for tanks from 65 metres to 120 metres in diameter. Once the tank-sweep nozzle hasbeen installed in the tank shell, via a “hot tapped” hole, the complete system can be assembled externally, the assembly includes the following items:
- numerous tank sweep nozzles
- filter housings
- high flow solids/liquid handling pumps
- large bore, high pressure hoses
Operation
| Typical System Lay-out |
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Once the system has been assembled and its integrity tested, each nozzle can be safely deployed into the tank via the valve at each hot tapped hole.
Once the nozzles have been successfully deployed, the nozzle jets are then positioned in such a way as to create a circulation process once the pumps have been started. (See diagram opposite) Once the pumps have been started, there speed is gradually increased until the desired flow & pressure has been achieved. Each nozzle has a 180 degree rotation which is controlled by a hand wheel from outside the tank.
DML also supply and operate the specialised equipment for the safe and efficient removal of the remaining cleaned sands/solids.
Within the Denholm Oilfield Services Group we have the capability to provide both the equipment and manpower to undertake the “Hot Tapping” operations required for the installation of the Denholm Tank-sweep Nozzles.
