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 is removal requires adsorption or ‘boiling off,’ which adds extra cost 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.
Using Industrial Centrifuges for Waste Oil Recycling
Waste Oil Centrifuge – 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.
Have you considered a centrifuge for Pyrolysis Oil separation? Read our article using Industrial Centrifuges for Pyrolysis Oil production.
Popular Alfa Laval Waste Oil Centrifuge Models