Centrifugation

Centrifugation

Type of treatment: Pretreatment

Description:

Separation of phases: oil - water – sediment using specific centrifugation machine.


Waste:

Liquid (with limited fraction of sediments, threshold depends on equipment).
Simple centrifugation may also be used to recover oil form heavily polluted sands.


Situation/Possibilities in the country:

Equipment easy to import and implement in any country.


Interest:

Allow separating oil, water and sediment. Recovered oil may be re-used.


Entry criteria:

Typical feed limit characteristics for centrifugation equipment:

• Oily sludge pumpable by standard volumetric pumps
• Dry solid content : maximum 15 %
• Grain size : no particles bigger than 5 mm (plastic, sand, stones, wood, rust and other materials)
• Oil content : 0 - 100 %
• Water content : 0 - 100 %

Note. Other equipment allow centrifugation of heavily oiled sands.
 


Operational constraints:
Requires personnel, site (surface of 200 m2 minimum), and input:
- Electrical supply
- Polymer (flocculant) powder can be used to facilitate the recovery of fine sediment (use 10 to 12 kg per ton of dry solid)
- Demulsifying chemicals can be used for emulsion.

Water may be required in case of heavy sludge with low water content, to liquefy the product before inputting into the centrifugation machine.


Impacts:

Minimal if equipment is suitable, correctly operated and there are no oil leaks.


Legal constraints:

Refer to those applying to the transport, handling and storage of oil products.


Efficiency:
Typical maximum flow rate :
- 750 kg dry solids per hour
- 12 m3/h maximum. Based on experience, 40 to 60 cubic meter of sludge can be treated daily (based on an 8 hours working day).
Quality of oil recovered:
- Contains 5% < BSW < 10%. Depending on the type of mud and machine tuning.
- Quality of water output by centrifuge machine:
- Contains 2%<oil<10% and 0,1%<SPM<3%. Depending on the mud & machine tuning.
- Water can be retreated in a lamellar decanter to reach a content of oil inferior to 0,1% and SPM inferior to 0,1%.
Quality of sediment:
- Contains 5 < Oil leachate < 10% and 30% < DS < 45%.

Depends on the type of mud, machine tuning and additives (flocculants).


Cost:
CAPEX: example of mobilisation cost for centrifugation equipment with above mentioned efficiency:
- Trans Mediterranean transport of equipment (2 x open-top containers: 1 x 20 ft container, and 1 x 40 ft container) : approx. 10,000 euros
- Installation and start-up: approx. 25,000 euros

OPEX: Treatment of 1 cubic meter of sludge (using centrifuge decanter and lamellar decanter for the water and including flocculants and de-emulsifier): approx. 60 euros/ m3 of sludge treated.

published on 2019/12/10 14:45:51 GMT+0 — last modified 2019-12-10T14:45:51+00:00