Sulfur in crude oil

Note, however, the particular cases of sulfur in crude oil from Rozel Point (Utah, USA) 13.95% in crudes from Etzel (Germany) 9.6% or crude from Gela... 

Sulfur in crude oils is mainly present in the form of organosulfur compounds. Hydrogen sulfide is the only important inorganic sulfur compound found in crude oil. Its presence, however, is harmful because of its corrosive nature. Organosulfur compounds may generally be classified as acidic and non-acidic. Acidic sulfur compounds are the thiols (mercap-tans). Thiophene, sulfides, and disulfides are examples of non-acidic sulfur compounds found in crude fractions. Extensive research has been carried out to identify some sulfur compounds in a narrow light petroleum fraction.Examples of some sulfur compounds from the two types are ... 

The question of the presence of elemental sulfur in crude oils was also a matter of controversy for many years. Many virgin crude oils contain small but significant amounts of PfyS that is easily oxidized to elemental sulfur by exposure to air. API 48 confirmed that elemental sulfur indeed does exist in some crude oils but it is not common in most cases dissolved Sg is a minor part of the total sulfur. 

Photometry and colorimetry are used by crude oil chemists to determine the content of different metals and heteroatomic compounds in crude oil and petrochemical products. Many references on photometry and colorimetry are given at the end of this chapter. Many authors have described the successful analysis of different metals in motor fuels by photometric and colorimetric methods. The composition of additives used during fuel production can be characterized by photometric and colorimetric methods because very many additives contain metals. It is not only fuels that can be characterized by photometry and colorimetry. Lubricants, which contain metals as an important component, can be successfully determined by these methods. These methods can quickly give qualitative information on heavy metals and heteroatomic compounds such as oxygen and sulfur in crude oil. More on this topic can be found in references 76 and 77 at the end of this chapter. 

This paper examines the use of the XRT (X-ray Transmission) technique as applied to the analysis of sulfur in crude oil. XRT may also be referred to as XRA (X-ray Absorption). 

The XRT method is better suited than XRF for the process control of sulfur in crude oil. Future work is required to determine the response time of the instrument to step changes in sulfur concentration and to test flowing conditions of the sample. 

Table 34.1 Mass fractions of sulfur in crude oil itself and in different crude oil fractions [7],...

The hydrogen sulfide available from natural gas, cracking-still gas and refinery gas, along with the sulfur in crude oil, amounts to more than enough to produce the entire sulfuric acid needs of the nation,... 

Murillo, M., Carrion, N., and Chirinos, J. (1993). Determination of sulfur in crude oils and related materials with a parr bomb digestion method and inductively coupled plasma mass spectrometry.J. Anal. At. Specirom. 8(3), 493-496. 

This test method also covers the determination of sulfur in crude oil. (See 12.1.3.)... 

The percentage of sulfur in crude oils ranges from nearly zero for certain high-API-gravity crude oils to as high as 7.5 per cent in a few very heavy crude oils (see Appendix B). Such a high piercentage of sulfur means that more than half of the compounds in the crude oil may contain sulfur. 

To guarantee that both the experimental distillations and the characterizations of crude oil and its fractions are correct, mass balances have to be performed. In other words, the amount of distilled crude oil must be equal to the sum of amounts of all distillates, the amount of sulfur in crude oil must be equal to the sum of amounts of sulfur in distillates, and so on for some other properties. Figure 1.13 shows the global mass balance and the sulfur balance during distillation of the 13°API crude oil. The differences obtained from these mass balances are quite small and acceptable, and are due to experimental errors during distillation and analysis. 

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