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 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 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.