Removal of Sulfur from Petroleum Streams
Sulfur is present in all crude oils to some extent, ranging from less than 1
wt% in many light, sweet crudes to 7 wt % in heavy crudes and tar sands
bitumen. It has been known for some time that sulfur in transportation fuels
is a major contributor to “acid rain” through the production of sulfur oxides
(SOx); and as a result, fuels are routinely hydrotreated to lower the sulfur
content prior to sale. In the past two decades, however, it has been found
that the sulfur content of fuel has a direct bearing on the amount of nitrogen
oxides (NOx) also produced during combustion, and that lowering the sulfur
content of the fuel is an effective way of controlling NOx. Therefore, in the
U. S. and elsewhere beginning in 2006, the sulfur content of gasoline has
been mandated to 30 ppm or less and the sulfur content of diesel has been
mandated to 15 ppm or lower.
This would not be so critical if the world’s supply of lighter, lower sulfur
crude oils was in plentiful supply, However, these crudes are rapidly
becoming depleted (see the discussion of Peak Oil here and here) and our
supply of crude is being supplanted by heavier, higher sulfur crudes and
heavy oils from Saudi Arabia, Canada and Venezuela. While conventional
hydrotreating works well to remove this sulfur, such processes are capital
intensive and consume vast quantities of hydrogen, thereby driving up
operating costs.
Therefore, there is both a need to (1) remove bulk sulfur from high sulfur
Canadian tar sands bitumen and Venezuelan Orinoco tar and (2) low levels
of sulfur from lighter streams in a less capital and operating cost intensive
manner. Trans Ionics is developing three such processes for sulfur
removal: (1) one for removal of low levels (<20 ppm) sulfur from Ultra Low
Sulfur Diesel (ULSD) “transmix” which is called TransFining-D, (2) one for
removal of slightly higher levels of sulfur and aromatics from motor gasoline
called TranSep-G and (3) and a third more radical process for sulfur
removal from heavy oil and tar sands bitumen called TransFining-R. Both of
the processes are unique in their applications and approaches to sulfur
removal.
Please contact us for more details.
Printer Friendly Page
Return to Technology page.
Technology: Desulfurization
