A review of the desulphurization methods used for pyrolysis oil

In this article we review the different methods that are used for the desulphurization of pyrolysis oil obtained from used tyres. A lot of research has been done on desulphurization of crude oil and its derivatives, mostly diesel. Since pyrolysis oil has similar properties to those of diesel, the methods employed can be extended and applied for the purification of pyrolysis oil. According to the ultimate analysis, pyrolysis oil contains about 1.6 wt% sulphur which is above environmental limit of 0.10 wt%. This investigation limits the methods of sulphur removal studied to; hydrodesulphurization, desulphurization by oxidation, extraction, adsorption and precipitation. Our findings are that the most expensive of these methods is hydrodesulphurization, mainly because of the high consumption of hydrogen as well as high temperature (320-450oC) and pressure (20-200bar) required for the process.