The environmental benefits of used oil re-refining have been compared to

· Refining of virgin base oil; and

· Use of the used oil as a combustion fuel substitute

The report, Commissioned by the G.E.I.R., (Groupement Européen de l'Industrie de la Régération) concludes that re-refining leads to a decrease in Environmental burdens in both instances. The G.E.I.R. is the representative organisation of the re-refining industry in Europe, based in Brussels. For further information, visit http://www.geir-regeneration.org/en/view. The report “Ecological and energetic assessment of re-refining used oils to base oils”, Feb 2005 is available free of charge at the above web site.

Conclusions

The assessment leads to the following main conclusions:

1. There are clear environmental benefits for re-refining as compared to the production of base oils in conventional oil refineries. This is true for all of the impact categories considered. See the figure below

2. The result of comparing re-refining against combustion of the used oil is strongly influenced by the question of which primary fuels are substituted by waste oil combustion. Where the fuel to be replaced is fuel oil or gas, re-refining is superior to combustion in all impact categories. Where coal and petroleum coke are substituted by used oil, combustion yields a larger greenhouse benefit than regeneration but is an inferior solution for other impact categories.

Source IFEU— Fehrenbach, H. “Ecological and energetic assessment of re-refining used oils to base oils”, Feb 2005

 

Interpretation of Results

The study considers the impact with regard to using re-refined base oil to

· substitute base oil refined from crude

· substitute a 70:30 mix of base oil and synthetic base oil (both sourced from crude oil)

· substitute fuel oil in burning applications

· substitute coal in burning applications

 

The six impact categories considered are

1. Resource depletion     kg raw oil-eq /kg

kg of resources depleted (eg crude oil, gas, coal) expressed in terms of equivalence to raw oil consumption (on energy equivalent basis) per kg of base oil

 

2. Global warming          kg CO2-eq/kg

kg of greenhouse gas (CO2, CH-4, N2O) expressed as equivalent CO2 emission per kg of base oil

 

3. Acidification              kg SO2-eq/kg

Emission of species which lead to acid rain

 

4. Nutrification              kg NOx-eq/kg

Emission of species which lead to nitrification of ecosystems

 

5. Human Toxicity         kg Arsenic-eq/kg

Emission of species toxic to human health

 

6. Fine Particles            kg PM10-eq/kg

Emission of fine particulate matter which can act as a carry for toxic & carcinogenic subastances into lungs.

 

To understand these units an example using the greenhouse unit of measure (CO2-eq/kg) may be worthwhile. Nitrous Oxide (N2O) is a greenhouse gas with 310 times the impact of CO2. So 1 kg of N2O is equivalent to 310 kg CO2 in greenhouse impact terms. Thus, any N2O emissions are factored by 310 times and reported as a CO2 equivalent impact.

 

Magnitude of the Greenhouse Figure

Because of the magnitude of the impact of crude oil refining is so many more times greater than re-refining for resource depletion, the scale on the above chart appears to make the other effects small. This is not the case. To illuminate the magnitude of the environmental effects and to make the normalisation presented in the graphs meaningful, the following example for Global Warming may be useful. From the results used to generate the chart, when re-refined oil is used as a substitute for virgin base oil from a crude oil refinery, then

The average CO2 equivalent burden of re-refining is 676 kg CO2-eq

The average CO2 equivalent burden of virgin base oil is 1156 kg CO2-eq

 

The net benefit is 1156 - 676 = 480 kg CO2 per Tonne of used oil or 42%

 

This leads to the conclusion that the impact on the greenhouse effect is 42% lower for re-refining compared to conventional refining. The benefit is even more substantial for the other impact categories.

Lifecycle Impacts of Re-Refining