Desulphurization of Diesel by Cellulosic Fiber

The new stringent global regulation to produce low sulfur petroleum products has put
most refineries in alert to research and implement new technology to meet the
requirement to lower emission of Sulfur Dioxide and Hydrogen Sulfide. European
country has set Euro 4 rule in 2005 to limit sulfur content in gasoline and diesel to 50
ppm maximum. In Malaysia, Euro 4 M standards will be implemented in two years’ time
from current Euro 2M standard of 500 ppm sulfur content. Most oil and gas and
petrochemical companies are developing technologies that cover enhanced
hydrotreatment process. This project explored the use of abundant palm oil fibers as the
mean of desulphurization. OPEFB cellulose structure was modified with carboxylic
group treatment such as acetic acid, oxalic acid, and EDTA. Metal ions such as Copper,
Zinc, and Lead are loaded into the pores of modified cellulose such that the positively
charged metal ions will capture the slightly polar sulphur atom of Dibenzothiophene by
removing the organosulphur and toxicity due to the Benzene ring.
The sorption processes of heavy metals on modified cellulose were performed in a batch
mode by varying the contact time, initial metal concentration and pH of the solution. The
samples were tested with Atomic Absorption Spectrum analyzer to measure the
concentration of metal ions adsorbed. Lead has shown highest adsorption capacity of
8.5mg/g cellulose EDTA adsorbent with 120 minutes contact time and 8.1mg/g in
cellulose oxalic. Zn adsorption came second at 6.8 and 6.4 mg/g cellulose EDTA and
cellulose oxalic respectively while Copper was recorded at 6.6 and 6.2mg/g adsorbent.
The metal ions adsorption fit Freundlich isotherm model and Pseudo 2nd Order kinetic
trending. Sulphur removal study is performed by batch contacting 0.1 g of the metal
loaded cellulose with 10 mL of diesel. Treatment by cellulose EDTA loaded with Lead
provide sulphur removal of 52.2%, Copper (14.9%) and Zinc (16.4%) while cellulose
oxalic dispersed in Lead solution result in reduction of 44.8%, Copper (29.9%), and Zinc
(28.4%).