Sour crude oil is crude oil containing the impurity sulfur. It is common to find crude oil containing some impurities. When the total sulfur level in the oil is > 1 % the oil is called “sour”.
The impurities will need to be removed before this lower quality crude can be refined into gasoline, thereby increasing the cost of processing. This results in a higher-priced gasoline than one made from sweet crude oil. Thus sour crude is usually processed into heavy oil such as diesel and fuel oil rather than gasoline to reduce processing cost.
(source: www.netl.doe.gov)
The majority of the sulfur in crude oil occurs bonded to carbon atoms, with a small amount occurring as elemental sulfur in solution and as hydrogen sulfide gas. Sour oil can be toxic and corrosive, especially when the oil contains high levels of hydrogen sulfide. At low concentrations the oil has the smell of rotten eggs, but at high concentrations the inhalation of hydrogen sulfide is instantly fatal. At higher concentrations, the hydrogen sulfide can damage the olfactory nerve, rendering the gas effectively odorless and undetectable, while paralyzing the respiratory system. If exposure is not fatal, its effects on the human body are similar to that of Gulf War Syndrome including chronic fatigue, headaches, dizziness, skin problems, memory problems, birth defects, and a host of breathing problems such as asthma. Such sour crude oil needs to be stabilized by having hydrogen sulfide gas (H2S) removed from it before being transported by oil tankers for safety reasons.
Venezuela, Saudi Arabia, Iraq, Kuwait, Iran, Colombia, Alberta, Mexico, Russia, Egypt and Syria are major producers of sour crude oil.
Article Source: www.wikipedia.org
