lubricating oils are different than vegetable oils or fats, you can only use lubricants in severe hydrocracking to produce diesel that is like hydrodiesel

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Like Andras said... You can only use to produce hydrodiesel. You cannot use to transesterification method.

Dear andi Mulkan

The following article will be very useful for you research i hope

Article Production of diesel-like fuel from waste engine oil by pyro...

Yes,

go for two step transesterification

My papers may help you

Article Production of biodiesel from unused algal biomass in Punjab, India

Article Fuel properties and emission characteristics of biodiesel pr...

Dear Andi Mulkan ,

Firstly, make sure that the waste lubricant oil is bio-based. This means the oil should be any product derived from some plant or animal-based oil or fat. This is very important if you are using biocatalysts as most lubricant oils are synthetic and lack fatty acids, which serve as a fundamental block for their metabolism and conversion into biodiesel.

In case if your oil is indeed bio-based, then it is absolutely necessary to purify and refine your oil before processing it into biodiesel. Purification and refining mean the oil has to be filtered both from settled and suspended solid wastes, then decolored, deodorized, washed, dried, and degummed before starting your reaction. Since, its lubricant oil you should pay attention to the free fatty acids and peroxides produced during the oil's use as lubricant.

Hope this clarifies your queries and wish you good luck with your work.

Regards,

Gokul Raghavendra Srinivasan

Thank you for all Prof/Dr/colleague

Hi

The processing protocols are well explained in the following paper:

https://doi.org/10.1007/s12161-021-02203-0

I hope this helps!