The first step in filtering cooking oil for use as diesel fuel is to allow it to settle, followed by progressively finer filtration to remove impurities that can damage your engine.
Here's a detailed breakdown of the process:
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Settling: Let the used cooking oil sit undisturbed for a week or longer. This crucial step allows solid particles (food scraps, fats) to sink to the bottom. Skipping this will quickly clog your filters.
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Initial Filtration (Coarse): Carefully pour the clear oil from the top of the settled container, avoiding disturbing the sediment at the bottom. Run this oil through a coarse filter. A 100-micron screen filter into a 55-gallon drum is a common starting point.
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Progressive Filtration (Finer): Further filtration is necessary to achieve the required purity for diesel engines. This usually involves passing the oil through progressively finer filters:
- 50-micron filter: Remove more of the particulate matter.
- 20-micron filter: This is a typical secondary filtration stage.
- 5-micron filter: This is often the final filtration step before using the oil in your vehicle. Some advocate for even finer filtration.
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Water Removal: Water is a major contaminant. Water can be removed through:
- Settling: Allow water to settle at the bottom of the tank and drain it off.
- Heating: Heating the oil to around 140°F (60°C) can help evaporate water. (Be careful: Avoid overheating, which can degrade the oil).
- Water absorbing filters: Some filters are specifically designed to remove water from oil.
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Testing: Before using filtered cooking oil as fuel, it's advisable to test its quality. Check for:
- Viscosity: High viscosity can lead to poor atomization in the engine.
- Water content: Ensure minimal water is present.
- Acidity: High acidity can corrode engine parts. Titration kits can be used to measure acidity.
Important Considerations:
- Source of Oil: The type of cooking oil (e.g., vegetable oil, animal fat) can affect the filtration process and fuel quality.
- Filter Type: Use filters specifically designed for oil filtration, as they are resistant to the chemical properties of the oil. Paper filters are often unsuitable.
- Regular Filter Changes: Replace filters regularly to maintain optimal flow rate and filtration efficiency. Clogged filters reduce fuel flow and engine performance.
- Vehicle Compatibility: Not all diesel engines are compatible with used cooking oil (WVO). Check your engine manufacturer's recommendations and consider any necessary modifications. Older diesel engines are typically more tolerant.
- Legal Considerations: Check local laws and regulations regarding the use of alternative fuels in vehicles.
By following these steps and paying careful attention to detail, you can effectively filter used cooking oil for use as a diesel fuel alternative. Remember safety precautions and the need to check your vehicle's compatibility with WVO, along with all applicable legal regulations.
