Re-Refining of Waste Oil
Formally, as long as 50 years ago, lots of small independent so-called re-refiners had set themselves up in business in America, Europe and even parts of South Africa.
The re-refining methods used were Heath Robinson and consisted of:
- Chemical treatment
- Heating, bleaching and filtration
The quality of the product was poor, it had:
- A very dark colour
- A distinctive re-refined oil odour
- A low flash point
- A high neutralisation, saponification value, ash content, demulsibility, carbon residue etc.
Because the waste oil was virtually undisposable without severely contaminating the environment, service stations and industrial concerns paid waste (used) oil dealers to take it away, therefore re-refined oil was virtually half the price of virgin lubricating oil.
That was then, times have changed…
Due to legislative changes by governments worldwide, waste oil is classified as a hazardous waste. This waste oil should be collected and processed back to its original virgin oil condition.
New recycling plants that are being built worldwide meet the stringent anti-pollution requirements and are able to produce group II base oils from crude. In the Euro Zone and Brazil for instance, recycling is mandatory and saves the economy.
Nowadays these are sophisticated plants with state of the art technology; the methods used are very complicated and involved, requiring huge capital outlays. They usually consist of dehydration, de-metallisation, film evaporation, hydro-treatment etc and water effluent treatment plants being a pre-requisite. No environmentally hazardous wastes are discarded and catalysts and other chemicals are recycled.
Did you know?
In the Euro Zone and Brazil recycling is mandatory and saves the economy 8 litres of base oil for every 10 litres of waste oil which is recycled four times over.
The burning of waste oil as fuel, causes the release of carcinogenic gases into the air. It is estimated that burning 20 litres of waste lubricating oil can release up to 25 grams of substances such as lead, cadmium, nickel, chromium, zinc and other chemical compositions.
There are now up to 7 new recycling plants operating in the world today with several under construction.
Lubricating oil only constitutes between 2 - 3 % of a barrel of crude oil it is becoming a scarce and valuable resource
In South Africa there are 2 lubricating oil refineries in Durban, producing Group I base oils. Other lubricating oils are all imported. Each one has an input of around 200 million litres of waste oil per annum, which is equal to virtually half the total lubricating oil requirements of the whole of South Africa.