Oil recycling

Oil recycling involves recycling used oil

Automotive oil
Automotive oil recycling involves the recycling of used oils and the creation of new products from the recycled oils, and includes the recycling of motor oil and hydraulic oil. Oil recycling also benefits the environment: increased opportunities for consumers to recycle oi l lessens the likelihood of used oil being dumped on lands and in waterways. For example, one gallon of motor oil dumped into waterways has the potential to pollute one million gallons of water.

Motor oil


Recycled motor oil can be combusted as fuel, usually in plant boilers, space heaters, or industrial heating applications such as blast furnaces and cement kilns. Recycled motor oil can be distilled into diesel fuel or marine fuel in a process similar to oil re-refining, but without the final hydrotreating process. The lubrication properties of motor oil persist, even in used oil, and it can be recycled indefinitely.

Used motor oil re-refining
Used oil re-refining is the process of restoring used oil to new oil by removing chemical impurities, heavy metals and dirt. Used Industrial and automotive oil is recycled at re-refineries. The used oil is first tested to determine suitability for re-refining, after which it is dehydrated and the water distillate is treated before being released into the environment. Dehydrating also removes the residual light fuel that can be used to power the refinery, and additionally captures ethylene glycol for re-use in recycled antifreeze.

Next, industrial fuel is separated out of the used oil then vacuum distillation removes the lube cut (that is, the fraction suitable for reuse as lubricating oil) leaving a heavy oil that contains the used oil's additives and other by-products such as asphalt extender. The lube cut next undergoes hydro treating, or catalytic hydrogenation to remove residual polymers and other chemical compounds, and saturate carbon chains with hydrogen for greater stability.

Final oil separation, or fractionating, separates the oil into three different oil grades: Light viscosity lubricants suitable for general lubricant applications, low viscosity lubricants for automotive and industrial applications, and high viscosity lubricants for heavy-duty applications. The oil that is produced in this step is referred to as re-refined base oil (RRBL).

The final step is blending additives into these three grades of oil products to produce final products with the right detergent and anti-friction qualities. Then each product is tested again for quality and purity before being released for sale to the public.

Vegetable oil
Vegetable oil recycling is increasingly being carried out to produce a vegetable oil fuel. In the UK, waste cooking oil collection is governed by the environment agency. All waste cooking oil collections need to be carried out by a company registered as a waste carrier by the environment agency. On each collection a waste transfer note needs to the filled out and copies held by both parties for a minimum of 3 years. Waste transfer notes need to contain:

Full company details of who the waste is being transferred to:
 * 1. Their waste registration details
 * 2. Full details of who the waste is being transferred from
 * 3. Date
 * 4. Signatures from both parties

Waste transfer notes can be hard paper copies or electronic versions. Here is an example of a waste transfer note currently is use by a UK waste cooking oil company.

Opportunities for businesses and consumers to recycle used cooking oil ("yellow grease") has increased. Used cooking oil can be refined into different types of biofuels used for power generation and heating. A significant benefit is that biofuels derived from recycled cooking oil typically burn clean, have a low carbon content and do not produce carbon monoxide. This helps communities to reduce their carbon footprints. The recycling of cooking oil also provides a form of revenue for restaurants, which are sometimes compensated by cooking oil recyclers for their used deep fryer oil. Cooking oil recycling also results in less used oil being disposed of in drains, which can clog sewage lines due to the build-up of fats and has to be collected there as "brown grease" by grease traps.

Vegetable oil refining is a process to transform vegetable oil into fuel by hydrocracking or hydrogenation. Hydrocracking breaks larger molecules into smaller ones using hydrogen while hydrogenation adds hydrogen to molecules. These methods can be used for production of gasoline, diesel, and propane. The diesel fuel that is produced has various names including green diesel or renewable diesel.

In the past waste oils were collected by pig farmers as part of food waste from pig swill bins. The grease was skimmed off the swill tanks and sold for further processing, while the remaining swill was processed into pig food.

Recycling one gallon of vegetable oil can save 576/37 pounds of a year, 10,800,000/17 btus of energy, 4,800/37 gallons of, 1,000/187 pounds of , gain almost 39/925 tons of  per year

(equal to 12/37 trees)