Dolphin Centrifuge

Waste Oil Centrifuge

waste oil centrifuge

Table of Contents


A waste oil centrifuge works by exerting gravitational forces up to 12,000 Gs to separate sediment and water from waste oil. This force separates particles as small as 1-micron from the oil. The centrifuge has a flow-through design that enables the continuous flow of the separated contaminants through separate outlets.

Industrial centrifuges offer a large processing capacity. Continuous three-phase separation is the key to the efficient separation of waste oils.

Three-phase separation means the separation of the three phases in contaminated oil. The 3 phases are the light phase – oil, heavy phase – water, and sludge.

A waste oil centrifuge is a heavy-duty, industrial-grade machine. It has the added capacity to ‘self-eject’ the separated solids. It also discharges the separated water continuously.


Industrial centrifuges used for waste oil purification are sized based on their throughput of processing capacity. Centrifuges from 3 Gallons per Minute to over 100 Gallons per Minute are available for sale. Due to the higher levels of sludge in waste oil compared to lube or hydraulic oil, self-cleaning centrifuges are required for waste oil processing.

Processing temperature is a key consideration while sizing waste oil centrifuges. Higher process temperature reduces the oil viscosity which enables higher throughput. Conversely, lower temperature oil leads to lower capacity through the same centrifuge.

As an example, consider our medium capacity, self-cleaning, Alfa Laval centrifuge, which is widely used for waste oil recovery. Notice the reduction in capacity at reduced oil temperature.

Advantages of Centrifuges Over Filters


Centrifuge Model Alfa Laval MOPX207 Self-Cleaning, Disc Stack Alfa Laval MOPX 210 Self-Cleaning, Disc Stack
Rated Capacity 32 GPM 72 GPM
Waste Oil Capacity @ 70 F (Ambient) 5 ~ 7 GPM 12 ~ 15 GPM
Waste Oil Capacity @ 140 F 10 ~ 12 GPM 20 ~ 24 GPM
Waste Oil Capacity @ 200 F 20 + GPM 45+ GPM
Drive Motor 7.5 HP 15 HP
Bowl Speed 7,200 RPM 5,100 RPM
Centrifugal Force 7,200 Gs 6,800 Gs
Separation Efficiency @ 200 F 1 µ Particle Size; All Free Water 1 µ Particle Size; All Free Water

Industrial Scale Waste Oil Processing

Small scale centrifuges (open, top-loading type) produce approximately 2,500 g force. This force is enough to separate bulk sludge from the waste oil but not to separate the small particles.

Our industrial-grade Waste Oil Centrifuges generate up to 8,000 g's. Separation of microscopic solid particles from the contaminated oil needs a higher g-force. Industrial centrifuges best handle large-scale processing of waste oil. Alfa Laval disc stack centrifuges have a continuous flow-through design and are perfect for this application.

Industrial-scale waste oil centrifuges are NOT cost-competitive for DIY or small scale WVO separation. These waste oil centrifuges are workable for large scale or commercial processors. These are customers who seek to process at least of few hundred gallons of WVO or any waste oil per day. Our 'turn-key' waste oil purification systems range from 500 Gal/Day to over 10,000 Gal/Day.

Decanters For High Sludge Waste-Oil

Waste oil decanters are well suited for de-sludging of high sludge waste oil. Refinery waste slop and tank bottom sludge are typical examples. This process is also known as sludge thickening. A decanter centrifuge handles high levels of sludge (up to 40%) continuously. Alfa Laval decanters replace belt-presses and screw presses in many demanding high-sludge applications.

Waste Oil Filter versus Centrifuge

In this section, we will delve into commercial aspects of waste oil recycling using filters versus centrifuges.

Using Filters for Waste Oil Recycling

Filtration is not suitable for large scale processing of used engine oil due to the ongoing cost of labor and material involved.

Consider a large-scale used oil collector who wants to process 10,000 gallons per day. Their collection consists of WVO, UCO, Waste Oil, and any other used oil. The first step involves heating and settling to remove the free water.

This process requires significant tank volume with heat for the 'heating and settling' routine. Despite the time and heating cost, all free-water is still not removed by this method.

Let's not forget about the sludge left in the settling tanks! That sludge contains significant amounts of oil, which means lost revenue. Also, the tank bottoms need cleaning.

Next, filtering the decanted waste oil through bag filters is a labor-intensive process. Replacing and disposing of filter media adds to cost and time. Cleaner oil requires small mesh filters, which means frequent replacement of media, which means more material and labor costs.

The 'finished product' contains water. Water removal requires adsorption or 'boiling off,' which adds extra cost to the process. Water removal by settling adds time to the process.

The capital expense of centrifuge equipment is more compared to decanting and filtration. The payback period of a centrifuge system is short, considering all costs. It is often in months, depending on the volume of oil processed.

Waste Oil Separation Using Industrial Centrifuge

Waste Oil Processing - Industrial Scale

Waste Oil Centrifuge Operation - Process Flow Diagram for Industrial Scale Processing.

A decanter centrifuge is a heavy-duty continuous de-sludging machine. It generates approximately 3000 times the force of gravity by centrifugal force. The decanter centrifuge processes incoming crude oil to remove all solids from 1/2" down to 50 micron level in one pass.

The de-sludged oil and water are then pre-heated. A high efficiency inline electric heater heats the fluid. An inline electric heater is energy efficient because it heats only the in-process liquid. Heating the entire tank volume is wasteful.

The heated waste oil is now processed through a self-cleaning, high-speed disc centrifuge. These industrial centrifuges generate up to 12,000 times the force of gravity. This g-force is enough to separate all free water and solid particles down to the 0.5-micron level.

This centrifuge machine continuously separates the water and intermittently ejects the separated solids. A PLC is the local control panel that controls the entire process. It also controls the sludge ejection system.

The process illustrated and described above is ideal for commercial-scale purification of waste oil. This separation is a continuous process without media and labor costs.

Have you considered a centrifuge for Pyrolysis Oil separation? Please read our article using Industrial Centrifuges for Pyrolysis Oil production.

Alfa Laval Waste Oil Centrifuges Modules

The following models show 3 Alfa Laval centrifuges of different capacities on processing Used Engine Oil. Hover on each model for technical specifications.

Alfa Laval MOPX205 Waste Oil Centrifuge
Alfa Laval MOPX205 Waste Oil Centrifuge

Alfa Laval MOPX205 Waste Oil Centrifuge

Self-Cleaning æ Disc Stack Centrifuge

Technical Specs
Capacity: 5 GPM on Waste Engine Oil
Motor HP: 4 HP
Voltages: 230V / 460V
Skid Dim.: ~ 4′ x 5′
Skid Wt.: ~ 1500 lbs

Alfa Laval MOPX213 Waste Oil Centrifuge

Self-Cleaning æ Disc Stack Centrifuge

Technical Specs
Capacity: 40 GPM on Light Waste Oil
Motor HP: 15 HP
Voltages: 230V / 460V
Skid Dim.: 6′ x 6′
Skid Wt.: ~5000 lbs
Waste Motor Oil Centrifuge System
Waste Motor Oil Centrifuge System
Refinery Waste Oil Centrifuge
Alfa Laval WHPX513 Refinery Waste Oil Centrifuge

Alfa Laval WHPX513 Refinery Waste Oil Centrifuge

Self-Cleaning æ Disc Stack Centrifuge

Technical Specs
Capacity: 60 GPM on API 38 Waste Oil
Motor HP: 15 HP
Voltages: 230V / 460V
Skid Dim.: 5′ x 6′
Skid Wt.: ~ 5000 lbs


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