In the early 1900s, the sulphuric
oil used in automobiles would be burned by the
engine and emit a horrible smell. This was not
desirable and processes were invented to remove the sulphur. Today, in order for natural gas and oil to
be marketable the sulphur must be removed. There are
also legal limits on the contents of sulphur in
products. Sulphur content in oil and natural gas
ranges from traces to around 5 percent. If a crude
oil contains some sulphur it is called sour crude.
If it contains little or no sulphur it is called
Hydro treating is one way of
removing many of the contaminants from many of the
intermediate or final products. In the hydro
treating process, the crude oil is mixed with
hydrogen and heated to about 300 degrees Celsius.
The oil combined with the hydrogen then enters a
reactor loaded with a catalyst, which promotes
several reactions. Hydrogen combines with sulphur to
form hydrogen sulphide (H 2S). The hydrogen sulphide
is a toxic gas that needs further treatment. The
combustion of a part of the H 2S stream in a furnace
produces sulphur dioxide, water, and sulphur. The
sulphur then can be removed safely. Oil sands mining
projects near Fort McMurray, Alberta also include
sulphur recovery as part of their facilities.
Upgraders remove most of the sulphur from bitumen by
converting it into elemental sulphur or retaining it
in a coke by-product. This can be used in many
products, such as fertilizers. The remaining sulphur
is released into the atmosphere as sulphur dioxide.