Sulphur Recovery Unit
Sweet crude oil is crude oil containing a sulfur of less than 5.0 percent, while sour crude oil is crude containing a high amount of the impurity sulfur of more than 5.0 percent. Sulfur impurities must be removed before refining the oil in the Sulphur recovery unit, and therefore its presence in the oil increases the cost of refining the crude oil. For this reason, light sweet crude oil, which allows the processing of lower sulfur and higher quality petroleum products, has a higher price and is more popular with refineries.
Hydrogen sulfide is one of the most dangerous impurities in crude oil and gas, which must be separated before refining. Removal of hydrogen sulfide from crude oil and its devastating effects on the environment and humans is one of the challenges of the oil industry. In addition, hydrogen sulfide causes severe corrosion of industrial equipment and serious poisoning in humans and living organisms. There are strict environmental regulations in the European Union for the transport of hydrogen sulfide, so that if the tanker cargo contains hydrogen sulfide above 15 ppm, it will not be allowed to unload cargo at ports.
The output fluid of oil wells usually has two phases (gas and oil) or three phases (gas, oil and water). Therefore, for extraction and consumption, they must be separated in some way. In the early stages, the fluid is usually separated using physical methods. For this operation, special devices called separators are used. After mechanical separation, there is still a significant amount of hydrogen sulfide in crude oil, which can not be separated by physical methods and chemical methods must be used.
Separation of hydrogen sulfide from crude oil is done in different ways. The most common and Affordable method of separation is the use of chemical substances that adsorb hydrogen sulfide. By adding these chemical subtances to crude oil, hydrogen sulfide is instantly dissolved in the chemical substance and excreted from the oil.