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PETROLEUM AND PETROLEUM PRODUCTS
1.1 INTRODUCTION
Petroleum (also called crude oil) is the term used to describe a wide variety of naturally occurring hydrocarbon-rich fluids that has accumulated in subterranean reservoirs and which exhibits considerably simple properties such as specific gravity/API gravity) and the amount of residuum (Table 1.1). More detailed inspections show considerable variations in color, odor, and flow properties that reflect the diversity of the origin of petroleum. From further inspections, variations also occur in the molecular types present in crude oil, which include compounds of nitrogen, oxygen, sulfur, metals (particularly nickel and vanadium), as well as other elements (ASTM D4175) (Speight, 2012a). Consequently, it is not surprising that petroleum can exhibit wide variations in refining behavior, product yields, and product properties (Speight, 2014a).
Table 1.1 Illustration of the variation in petroleum properties—specific gravity/API gravity) and the amount of residuum
| Petroleum | Specific gravity | API gravity | Residuum >1050°F (% w/w) |
| Agbami (Africa) | 0.790 | 48.1 | 2.5 |
| Alaska North Slope (US) | 0.869 | 31.4 | 18.3 |
| Alba (North Sea) | 0.936 | 19.5 | 32.7 |
| Alvheim Blend (North Sea) | 0.850 | 34.9 | 13.1 |
| Azeri BTC (Asia) | 0.843 | 36.4 | 13.2 |
| Badak (Indonesia) | 0.830 | 38.9 | 2.0 |
| Bahrain (Bahrain) | 0.861 | 32.8 | 26.4 |
| California (US) | 0.858 | 33.4 | 23.0 |
| Calypso (Trinidad and Tobago) | 0.971 | 30.8 | 11.6 |
| Dalia (Africa) | 0.915 | 23.1 | 27.7 |
| Dansk Underground Consortium (DUC) (Denmark) | 0.860 | 33.5 | 18.2 |
| Draugen (Europe) | 0.826 | 39.9 | 6.4 |
| Gimboa (Africa) | 0.912 | 25.3 | 24.0 |
| Grane (North Sea) | 0.940 | 19.0 | 30.3 |
| Hibernia Blend (Canada) | 0.850 | 35.0 | 17.2 |
| Iranian Light (Iran) | 0.836 | 37.8 | 20.8 |
| Iraq Light (Iraq) | 0.844 | 36.2 | 23.8 |
| Kearl (Canada) | 0.918 | 22.6 | 31.9 |
| Kutubu Bland (New Guinea) | 0.802 | 44.8 | 12.0 |
| Kuwaiti Light (Kuwait) | 0.860 | 33.0 | 31.9 |
| Marib Light (Yemen) | 0.809 | 43.3 | 7.7 |
| Medanito (Argentina) | 0.860 | 33.0 | 20.6 |
| Mondo (Africa) | 0.877 | 29.9 | 22.1 |
| Oklahoma (US) | 0.816 | 41.9 | 20.0 |
| Oman (Oman) | 0.873 | 30.5 | 30.5 |
| Pennsylvania (US) | 0.800 | 45.4 | 2.0 |
| Peregrino (Brazil) | 0.974 | 13.7 | 40.5 |
| Saudi Arabia | 0.840 | 37.0 | 27.5 |
| Saxi Batuque Blend (Africa) | 0.856 | 33.9 | 14.6 |
| Terra Nova (Canada) | 0.859 | 0.9 | 16.0 |
| Texas (US) | 0.827 | 39.6 | 15.0 |
| Texas (US) | 0.864 | 32.3 | 27.9 |
| Venezuela | 0.950 | 17.4 | 33.6 |
| Zakhum Lower (Abu Dhabi) | 0.822 | 40.5 | 14.3 |
Over the past four decades, the petroleum being processed in refineries has becoming increasingly heavier (higher amounts of residuum) and higher sulfur content (Speight, 2000, 2014a; Speight and Ozum, 2002; Hsu and Robinson, 2006; Gary et al., 2007). Market demand (market pull) dictates that residua must be upgraded to higher-value products (Speight and Ozum, 2002; Hsu and Robinson, 2006; Gary et al., 2007; Speight, 2014a). In short, the value of petroleum depends upon its quality for refining and whether or not the product slate and product yields can be obtained to fit market demand.
Thus, process units in a refinery require analytical test methods that can adequately evaluate feedstocks and monitor product quality (Drews, 1998; Nadkarni, 2000, 2011; Rand, 2003; Totten, 2003). In addition, the high sulfur content of petroleum and regulations limiting the maximum sulfur content of fuels makes sulfur removal a priority in refinery processing. Here again, analytical methodology is key to the successful determination of the sulfur compound types present and their subsequent removal.
Upgrading residua involves processing (usually conversion) into a more salable, higher-valued product. Improved characterization methods are necessary for process design, crude oil evaluation, and operational control. Definition of the boiling range and the hydrocarbon-type distribution in heavy distillates and in residua is increasingly important. Feedstock analysis to provide a quantitative boiling range distribution (that accounts for non-eluting components) as well as the distribution of hydrocarbon types in gas oil and higher-boiling materials is important in evaluating feedstocks for further processing.
Sulfur reduction processes are sensitive to both amount and structure of the sulfur compounds being removed. Tests that can provide information about both are becoming increasingly important, and analytical tests that provide information about other constituents of interest (e.g., nitrogen, organometallic constituents) are also valuable and being used for characterization.
But before emerging into the detailed aspects of petroleum product analysis, it is necessary to understand the nature of petroleum as well as the refinery processes required to produce petroleum products. This will present to the reader the background that is necessary to understand petroleum and the processes used to convert it to products. The details of the chemistry are not presented here and can be found elsewhere (Speight, 2000, 2014a; Speight and Ozum, 2002; Hsu and Robinson, 2006; Gary et al., 2007).
1.2 PERSPECTIVES
The following sections are included to introduce the reader to the distant historical and recent historical aspects of petroleum analysis and to show the glimmerings of how it has evolved during the twentieth century and into the twenty-first century. Indeed, in spite of the historical use of petroleum and related materials, the petroleum industry is a modern industry having come into being in 1859. From these comparatively recent beginnings, petroleum analysis has arisen as a dedicated science.
1.2.1 Historical Perspectives
Petroleum is perhaps the most important substance consumed in modern society. The word petroleum, derived from the Latin petra and oleum, means literally rock oil and refers to hydrocarbons that occur widely in the sedimentary rocks in the form of gases, liquids, semisolids, or solids. Petroleum provides not only raw materials for the ubiquitous plastics and other products, but also fuel for energy, industry, heating, and transportation.
The history of any subject is the means by which the subject is studied in the hopes that much can be learned from the events of the past. In the current context, the occurrence and use of petroleum, petroleum derivatives (naphtha), heavy oil, and bitumen are not new. The use of petroleum and its derivatives was practiced in pre-Christian times and is known largely through historical use in many of the older civilizations (Henry, 1873; Abraham, 1945; Forbes, 1958a, 1958b, 1959, 1964; James and Thorpe, 1994). Thus, the use of petroleum and the development of related technology are not such a modern subject as we are inclined to believe. However, the petroleum industry is essentially a twentieth-century industry, but to understand the evolution of the industry, it is essential to have a brief understanding of the first uses of petroleum.
Briefly, petroleum and bitumen have been used for millennia. For example, the Tigris–Euphrates valley, in what is now Iraq, was inhabited as early as 4000 b.c. by the people known as the Sumerians, who established one of the first great cultures of the civilized world. The Sumerians devised the cuneiform script, built the temple towers known as ziggurats, had an impressive law, as well as a wide and varied collection of literature. As the culture developed, bitumen (sometimes referred to as natural-occurring asphalt) was frequently used in construction and in ornamental works. Although it is possible, on this basis, to...
