Waste Oil Centrifuge
Table of Contents
Waste Oil Centrifuge – Operation
A waste oil centrifuge is an industrial centrifuge that continuously separates free water and fine sediment from used mineral oils. The high centrifugal force (up to 10,000 g) separates metal and carbon particles down to 0.5-micron levels from waste oil. Centrifuged waste oil still retains its black color due to suspended, sub-micron level carbon and ash particles.
Flow-through industrial centrifuges offer 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 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.
Sizing and Specification
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.
Centrifuge Specifications for Waste Oil (Used Engine oil)
|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 12,000 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 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.
Advantages of Centrifuges Over Filters for Waste Oil
- Total mechanical separation eliminates the need for filter media and labor costs.
- Continuous separation without the downtime/labor associated with filter replacement.
- High g-force allows the centrifuge to separate particles down to 0.5µ level.
- A waste oil centrifuge will also separate all free water.
- Breaking of waste oil emulsion.
- Removing ash and fine metal particles from used engine oil.
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 for Sale
The following models show 3 Alfa Laval centrifuges of different capacities on processing Used Engine Oil. Hover on each model for technical specifications.