Operation
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 waste oil. The centrifuge has a flow-through design that enables the continuous flow of the separated contaminants through separate outlets.
Industrial waste oil 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:
- Light phase — oil (the clean, recovered product)
- Heavy phase — water (separated and discharged continuously)
- Sludge — solid contaminants (intermittently ejected from the bowl)
A waste oil centrifuge is a heavy-duty, industrial-grade machine. It has the added capacity to self-eject the separated solids and discharge separated water continuously.
Pilot-scale Waste Oil Centrifuge Testing Video
Performance Results
How well does a disc centrifuge clean waste oil?
The following is a real-world example of our centrifuge performance results on waste oil. The table shows the contaminant levels in waste oil before and after an Alfa Laval MOPX-207 Centrifuge.
| Alfa Laval MOPX-207 Performance Data | ||
|---|---|---|
| Contaminant | Before | After |
| Sediment | 0.42% Wt. | 0.06% Wt. |
| Water | 38.0% Vol. | 1.2% Vol. |
| Trace Metals Removed: | ||
| Vanadium | 28 ppm | 31 ppm |
| Aluminum | 495 ppm | 85 ppm |
| Silicon | 386 ppm | 132 ppm |
| Ash Content | 1.17% Wt. | 0.09% Wt. |
Factors Affecting Centrifuge Performance
Temperature
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.
Flow Rate
Lower flow rates give higher retention time in the centrifuge bowl. This time enables longer exposure to the high centrifugal forces leading to better separation.
Inversely, higher flow rates lead to less effective separation.
Sizing
Industrial centrifuges used for waste oil purification are sized based on their throughput or processing capacity.
Centrifuges with processing capacities from 3 Gallons per Minute to over 100 Gallons per Minute are available for sale.
Due to the higher sludge levels in waste oil than in lube or hydraulic oil, self-cleaning centrifuges are required for waste oil processing.
For example, consider our medium capacity, self-cleaning Alfa Laval centrifuge, widely used for waste oil recovery. Notice the reduction in capacity at reduced oil temperature in the specifications below.
Packaged Systems
Dolphin Centrifuge offers complete, skid-mounted waste oil centrifuge systems in three capacity ranges. All models use self-cleaning disc-stack technology with continuous flow-through operation.
| Specification | Alfa Laval WHPX-405 | Alfa Laval WHPX-407 | Alfa Laval WHPX-513 |
|---|---|---|---|
| Capacity | 10 GPM | 30 GPM | 50 GPM |
| Bowl Speed | 8,000 RPM | 7,000 RPM | 5,000 RPM |
| Drive Motor | 5 HP | 10 HP | 20 HP |
| Footprint | 4' × 5' | 6' × 5' | 7' × 6' |
| Weight | 2,500 lbs | 3,500 lbs | 5,000 lbs |
| Solids Handling | Up to 5% | Up to 5% | Up to 8% |
The WHPX-407 and WHPX-513 provide full 3-phase separation — simultaneously discharging clean oil, separated water, and sludge through dedicated outlets.
Utilities & Installation
All Alfa Laval WHPX systems require 480V 3-phase electrical power and compressed air for the self-cleaning mechanism. Potable water for the seal flush is optional. Units are skid-mounted and install in a standard industrial space — no special foundation is needed.
Advantages of Centrifuges Over Filters
- Total mechanical separation eliminates the need for filter media
- Continuous separation without downtime Associated with filter replacement
- High g-force allows separation down to 0.5 micron level
- Complete removal of all free water from waste oil
Waste Oil Centrifuge FAQ
Can a disc centrifuge separate emulsified waste oil?
Can a waste oil centrifuge remove fine metal contaminants from the oil?
Can your waste oil centrifuge separate antifreeze or glycol from the oil?
What happens to the separated sludge in a waste oil centrifuge?
Can we use a waste oil centrifuge for other applications such as diesel purification?
How does a disc stack centrifuge differ from other open bowl waste oil centrifuges?
Is a waste oil centrifuge a flow-through type separator?
What is the smallest capacity Alfa Laval waste oil centrifuge?
Can a waste oil centrifuge remove the black color from waste oil?
Need Help Sizing a Waste Oil Centrifuge?
Tell us your daily volume, oil type, and processing temperature. Our engineers will recommend the right centrifuge system for your waste oil application. You can also read our guide on how to pick the right industrial centrifuge.
Specifications
The following table highlights the specifications of our most popular large-scale waste oil processing disc-stack centrifuges.
| Feature | MOPX-207 | MOPX-210 |
|---|---|---|
| Separation Quality | 1µ; Total Water Removal | 1µ; Total Water Removal |
| Rated Capacity | 32 GPM | 72 GPM |
| Actual Capacity at Temp: | ||
| @ 70°F (Ambient) | 5–7 GPM | 12–15 GPM |
| @ 140°F | 10–12 GPM | 20–24 GPM |
| @ 200°F | 20+ GPM | 45+ GPM |
| Drive Motor | 7.5 HP | 15 HP |
| Centrifugal Force | 7,200 Gs | 6,800 Gs |
| System Weight | 2,800 Lbs | 4,000 Lbs |
Black Diesel
Black diesel is a term used to describe used engine and other used mineral oils that are repurposed as fuel for diesel engines and diesel generators.
Separating sub-micron carbon and ash requires high G-force to achieve a combustible quality.
Installation
A typical waste oil centrifuge installation requires specific auxiliary equipment to ensure the long-term reliability and efficiency of the system.
Primary Requirements:
- Elevated Platform: Necessary for bottom-discharge sludge handling.
- Lifting Assistance: Disc stack bowls are industrial-weight components requiring mechanical hoists.
Access platforms
Catwalks provide safe operator access during bowl retraction and routine maintenance.
Sludge Management
A sludge receptacle with an automated transfer pump is the industry standard for waste handling.
Water Utilities
A stable, non-corrosive operating water supply is required for centrifugal bowl sealing.
Industrial Scale Processing
Small-scale centrifuges (open, top-loading type) produce approximately 2,500 Gs. This is enough for bulk sludge but fails to remove sub-micron particles.
Our industrial waste oil centrifuges generate up to 8,000 Gs. This force is essential for commercial-scale purification (500 to 10,000+ Gal/Day).
Technical Note
Industrial-scale systems are designed for commercial processors and are not cost-competitive for small DIY or backyard WVO setups.
Decanters for High Sludge
For waste oil containing up to 40% solids (refinery slop or tank bottoms), a decanter centrifuge is required.
Decanters handle heavy sludge loads continuously, replacing inefficient belt or screw presses in demanding industrial environments.
Waste Oil Filter vs. Centrifuge
Filtration is not suitable for large-scale processing of used engine oil due to the extreme ongoing cost of labor and filter media.
Consider a collector processing 10,000 gallons daily. Relying on settling tanks and bag filters creates a bottleneck. Manual filter replacement and sludge handling lead to lost revenue and increased overhead.
"The capital expense of a centrifuge is higher initially, but the payback period is often measured in months through labor savings and total oil recovery."
Industrial Process Flow
The Continuous Cycle:
- 1
Primary De-sludging: Handled by a decanter centrifuge to remove bulk solids (1/2" down to 50 microns).
- 2
High-Efficiency Heating: Inline electric heaters raise temp to 200°F only for active process fluid.
- 3
Disc Centrifuge Finishing: 12,000 Gs remove all free water and particles down to 0.5-micron level.
This separation is a continuous, automated process controlled by a PLC system. It eliminates the ongoing media costs and manual intervention required by legacy filtering methods.
Processing Pyrolysis Oil? Read about Industrial Centrifuges for Pyrolysis Oil production.
Used / Remanufactured Alfa Laval Centrifuges for Waste Oil Recovery
The following models show 3 Alfa Laval centrifuges of different capacities for processing Used Engine Oil. Hover on each model for technical specifications.
Alfa Laval WHPX-405
| Type: | 3-Phase; Self-Cleaning |
| Bowl RPM: | 8,500 RPM |
| G-Force: | 8,000 Gs |
| Capacity: | 5 GPM @ 180°F |
| Motor: | 4 HP |
| Power: | 460V; 20A |
| Size: | 4'×5'×5'H |
| Weight: | 1,800 Lbs |
Alfa Laval MOPX-209
| Type: | 3-Phase; Self-Cleaning |
| Bowl RPM: | 6,500 RPM |
| G-Force: | 8,000 Gs |
| Capacity: | 40 GPM @ 180°F |
| Motor: | 10 HP |
| Power: | 460V; 50A |
| Size: | 5'×6'×7'H |
| Weight: | 3,500 Lbs |
Alfa Laval WHPX-513
| Type: | 3-Phase; Self-Cleaning |
| Bowl RPM: | 6,300 RPM |
| G-Force: | 8,000 Gs |
| Capacity: | 60 GPM @ 180°F |
| Motor: | 15 HP |
| Power: | 460V; 60A |
| Size: | 6'×7'×7'H |
| Weight: | 4,500 Lbs |
Technical Reading
Waste Oil Recovery Case Study
Real-world results for ash and metal removal from used engine oils.
Used Oil Centrifuge Guide
Comprehensive overview of industrial centrifuge roles in oil recycling.
Pyrolysis Oil production
Separation and purification techniques for pyrolysis-derived fuels.
Mechanical Emulsion Breaking
Using 12,000 Gs to break chemical-free waste oil emulsions.
Black Diesel Centrifuges
Converting used engine oil into combustible diesel fuel.
Sample Testing Program
Validate centrifuge performance on your specific oil before purchasing.