How to remove Sulfur from crude oil

1. Why we make the process of
removal of sulfur from crude oil?
Sulfur in crude oil is mainly present in the form of organ
sulfur compounds. Hydrogen sulfur is the only important
inorganic sulfur compound find in crude oil.
Its presence however, is harmful because of its corrosive
nature organ sulfur compounds may generally be classified
as acidic and non acidic. Acidic sulfur compounds are the
thiols (mercaptans).
Thiophene, sulfides and disulfides are examples of non-acidic
sulfur compounds found in crude oil fractions.
Extensive research has been carried out to identify some
sulfur compounds in a narrow light petroleum fraction.

2. Most Common Methods Of Removal
Of Sulphur:
I.Catalytic Desulfurization.
II.Chemical Desulphurization.
III.Physical Adsorption Of Sulphur Oxide.
IIII.Wet Sulfuric acid process.
IV. Spray dry scrubbing using similar
sorbent slurries.

3. I. By Catalytic Desulfurization:
Hydrodesulfurization (HDS), the industry standard method of
removing sulfur in petroleum refining operations, uses types of
catalysts to add hydrogen in order to reduce unwanted sulfur
compounds. Unfortunately, the HDS process typically requires
expensive, high-pressure (up to 1,000 psig), high-temperature (400 –
550°C) equipment to help produce environmentally friendly fuels.
Hydrodesulfurization (HDS) is the standard catalytic process for
the removal of sulfur from petroleum products. In this process, the
sulfurous fractions of the crude oil are mixed with hydrogen and a
catalyst to react to hydrogen sulfide. Typically, the catalyst consists of
an alumina base impregnated with cobalt and molybdenum. As the
oilsupplies get more sour, higher pressures and alternative catalysts
are required for the desulfurization. Recalcitrant aromatic sulfur
compounds (e.g. 4,6-dimethyldibenzothiophene) cannot be removed
using hydrodesulfurization, due to their low reactivity

4. II.By Chemical Desulphurization:
a) Acid chromous chloride treatment.
b) Peroxyacetic acid treatment.
II.b)Peroxyacetic acid treatment:
Chemical desulphurisation was carried out according to the method
described by Palmer et al. 13 with some modifications. About 2 g of coal
(< 250 μm) in 70 mL of glacial acetic acid and 30 mL of 6% hydrogen
peroxide concentration were reacted at room temperature for a specific
reaction time.
The reaction mixture was cooled and the residual coal was filtered
and washed with excess of hot distilled water and dried in vacuum oven
set at 40˚C over night. The experiment was repeated at various reaction
temperatures of 50 and 104˚C (refluxing temperature).
The reaction was also conducted with various acids to peroxide
volume ratio of 50:50, 30:70 and 60:20 and with 30% hyrogen peroxide
concentration.

5. III.By Physical Adsorption Of
Sulphur Oxide:
One of the more promising processes for removal of S02 and NO,
simultaneously is the Bergbau-Forschung process that involves S02
adsorption and catalytic NO, reduction with ammonia by using
carbonaceous adsorbents 1281.
The mechanism and kinetics of adsorption of S02 fiom flue gas on
carbon is very complex due to the presence of water vapour and oxygen,
which leads to the formation of sulphuric acid. The adsorption capacity for
S02 is much greater than that of physical adsorption because of the
formation of H2S04.
Lu and Do studied the use of coal reject - a coal mine waste - as an
adsorbent. They found that the coal reject, when previously treated by
pyrolysis and activation, possessed considerable adsorption capacities for
both SO2 and NO.
This process presents the advantages of simultaneous removal of S02
and NO, and utilization of solid waste.