Crude Oil Centrifuge | Dewatering and Tank Bottom Recovery


Crude Oil Centrifuge | Dewatering and Tank Bottom Recovery

Crude Oil Tank Bottom Centrifuge

Design and Operation

An industrial centrifuge specifically designed to dewater crude oil and separate particulate matter is known as a crude oil centrifuge. These centrifuges exert high centrifugal forces (over 8,000 Gs) to remove all water and sludge particles continuously. Sale oil with less than 0.1% BS&W can be reliably reclaimed.

Crude oil centrifuges are mechanical separating machines used in O&G production applications. They perform a variety of separating functions in petroleum production. From drilling mud recovery to oil washing, centrifuges are a versatile tool in the petroleum industry.

Heavy sludge is the primary contaminant in all types of crude oil-related streams. It needs to removed to protect downstream equipment such as pumps, separators, wellheads, etc. A decanter centrifuge is the first line of defense for these heavy, abrasive solids. Alfa Laval decanters efficiently remove sludge and produce sludge-free oil. De-sludged oil is much easier to handle and treat for recovery of sale-oil.

In general, these oilfield centrifuges are subject to considerable wear and abrasion. Therefore, these oil centrifuges need to have robust construction and wear protection.

Dolphin Centrifuge has considerable experience in all applications using centrifuges for crude oil. Following is a summary of functions for which we have supplied centrifuges.

Applications in O&G Production

Drilling Mud Recovery

Solids control centrifuges are also known as drilling mud centrifuges or decanters. Oil well drilling requires lubrication for efficient operation. This lubricant is a mix of water and barite, which is a mineral.

Barite allows the drilling lubricant to work under high pressure in deep wells. The drilling mud carries crushed rocks when it flows back to the surface. Centrifuges separate drill fluids from the crushed solids as the drilling mud comes back to the surface.

Drilling mud solids are heavy and abrasive. They need heavy duty gearboxes, wear protection, tiled conveyors, and precision speed control. Wear protection ensures the highest efficiency and durability.

Dolphin Centrifuge has Alfa Laval solids control decanters for sale. Our drilling mud decanter modules include:

  • Transfer pumps.
  • Clean fluid tanks and return pumps.
  • Sludge transfer conveyor.
  •  Automated VFD control systems.

Oil Based Drilling Mud Recovery

Oil-based drilling mud (OBM) often uses diesel as the lubricant. The oil enhances the lubricity and better temperature resistance without breaking down.

Recovery of diesel from OBM is desirable due to the cost of oil. The diesel in used OBM carries colloidal solids, and the separation of these suspended solids is essential before reuse of the oil.

Decanters do not exert centrifugal force high enough to extract these suspended solids. A high speed, disc stack centrifuge generates enough force to separate these small particles.

Dolphin Centrifuge’s oil cleaning system is suitable for recovering diesel from de-sludged OBM. Our solution uses a self-cleaning, disc stack centrifuge to extract the colloidal solids. It can also break emulsified oil depending on the type of emulsion.

Tank Bottoms Recovery

Crude oil extracted from wells carries saltwater and sand or other sediments. Producers use settling tanks to skim sale oil from the top of settling tanks. The residue left in the settling tanks is known as tank bottoms.

Tank bottoms contain Basic Sediment & Water (BS&W). Skimming of sale oil leaves plenty of good oil in tank bottoms. This oil can is recoverable using our centrifuge system for extra revenue.

An oilfield centrifuge is a cost-effective solution for tank bottom processing to recover sale oil. The centrifuge also reduces tank bottom sludge thus significantly reducing tank cleaning costs.

Salt Water Disposals (SWDs) use Alfa Laval three-phase centrifuges for dewatering crude oil from produced water.

Dolphin Centrifuge has been working with owners and operators to recover tank bottom oil. We have engineered robust solutions for efficient, low-cost oil recovery using specially designed produced water centrifuges.

Dolphin designed & manufactured Oil Recovery System (ORS) is an ingenious solution for oil recovery. Our ORS incorporates the 3-Step process listed below for crude oil de-watering.

  • Heating and pre-straining to remove large impurities i.e., rocks, organics, etc.
  • De-sludging through a decanter centrifuge to remove heavy sludge.
  • Polishing the de-sludged oil through a disc stack centrifuge to separate all free water and remaining fine sediment.

Containerized Tank Bottom Recovery System

We have integrated a pre-strainer, decanter & crude oil centrifuge into a standard 40′ container. This system includes accessories such as pumps, heaters, sludge augers, buffer tanks, etc.

The design of the container is for ease of deployment and use in remote field locations. These modules have interior lighting, service crane(s), interconnecting pipes, automatic PLC control systems, etc.

Our containerized Oil Recovery System (ORS) is a ‘self-contained’ module. We designed it to process tank bottoms and recover sale oil with less than 0.1% BS&W.

You can see the latest version of our containerized ORS in the following video.

Skid Mounted Oil Recovery System

The ORS is also available in a ‘Skid Mounted’ design, which is suitable for fixed installation in existing facilities. We supply each of the 3-step components as an individual skid-mounted system.

The customer has the flexibility to configure the ORS around pre-installed tanks or other assets. Also, the skid-mounted configuration offers lower cost and shorter lead-times.

The following image shows our Skid Mounted Oil Recovery System.

Crude Oil Recovery System - Modular
Crude Oil Recovery System – Modular

Refinery Slop Oil

Oil refinery waste streams are also known as refinery slop. This waste stream consists of wastewater, crude oil, and sludge. It often contains varying amounts of oil emulsions as well.

A refinery slop treatment system includes a crude oil decanter for de-sludging. A high-speed disc stack centrifuge separates the liquid phases in the de-sludged oil. If the emulsion is present, the use of chemicals helps the centrifuge break the oily-water mix.

Therefore, both decanter and disc stack centrifuge is well suited for refinery slop oil treatment.

Water Washing

Heavy metals such as lead, iron, arsenic, nickel, etc. are present in crude oil. Though their presence is in trace levels is not an issue, higher levels of metals can cause a problem for the producer. Oil companies do not want to buy crude oil with heavy metals beyond their specified level.

Certain types of crude oil are washable with water to remove heavy metals by adsorption. Water adsorbs the metals and needs to be separated. A 3-phase disc stack centrifuge recovers the crude oil from the wash-water.

Of course, this process creates a stream of water with adsorbed heavy metals. This contaminated water stream needs disposal through proper means.

Contact Dolphin Centrifuge for further information regarding the use of crude oil centrifuges. Let us use our expertise to your benefit!

Specifications

The following are the specifications for a typical Alfa Laval three-phase centrifuge processing API 40 Light Crude Oil

Centrifuge Make and Model Alfa Laval WHPX-510-TGT-24
Processing Capacity 25 GPM
Centrifuge Type Self-Cleaning, Disc-Stack Centrifuge (Auto Ejects Concentrated Sludge)
Bowl Speed 5,150 RPM
Centrifugal Force (RCF) 7,000 Gs
Sludge Volume 3.0 Gallons
Motor Power 15 HP (11 kW)
Dimensions & Weight 5′ x 6′ x 6′ (H)   4,000 Lbs
Algae Centrifuge from Alfa LavalAlgae-Harvesting-Centrifuge-MAPX207Algae centrifuge from Alfa LavalAlfa-Laval-NX418-Oilfield-Centrifuge
Alfa Laval WHPX 405
‘Self-Cleaning’ Disc Centrifuge
5 GPM on Light Crude Oil
Alfa Laval MOPX 207
‘Self-Cleaning’ Disc Centrifuge
25 GPM on Frac Water De-Oiling
Alfa Laval WHPX 510
‘Self-Cleaning’ Disc Centrifuge
40 GPM on Distillate
Alfa Laval NX 418 Decanter
Tank Bottom De-Sludging
2 BPM on API 38 Crude Oil