Oil crude

Crude oil varies in its properties and composite from one country to another and from field to field. The differences are due to viscosity, volatility, and composition (e.g., sulfur content). A list of 14 different crude oils and their primary distillation products is given in Table 3.1. 

Crude oil is by far the most important resource for modern society. Approximately 450 refineries in the world convert crude oil into transportation fuels (gasoline, diesel, kerosene), lubricants and feed stocks for all sorts of chemicals. Catalysts play a key role in these processes [J.A. Moulijn, M. Makkee and A. van Diepen, Chemical Process Technology (2001), Wiley, Chichester], 

At the beginning of the 3 Millennium, the proven oil reserves amounted to 1.035 X 10 barrels of oil, of which roughly 2/3 are in the Middle East. The world consumption of oil in 1999 was about 27 x 10 barrels, implying that the proven reserves would be sufficient to allow the use of oil at the present consumption level for another 40 years at most. 

A modern refinery is a complicated collection of conversion processes, each tailored to the properties of the feed it has to convert. The scheme shown in Fig. 9.1 summarizes the most important operations some reasons for these processes are given in Tab. 9.2, along with relevant catalysts. First the crude oil is distilled to separate it into fractions, varying from gases, liquids (naphtha, kerosene and gas oil), to the heavy residue (the so-called bottom of the barrel ) that remains after vacuum distillation. 

Concepts of Modem Catalysis and Kinetics. I. Chorkendorff, J. W. Niemantsverdriet Copyright 2003 WILEY-VCH Veriag GmbH Co. KGaA, Weinheim ISBN 3-527-30574-2 

Fraction Boiling point (°C) Volume % Density (kg L- ) Sulfur (wt.%) (approx.) 

Crude oil is used both directly as a fuel and as a feedstuff for the petrochemical factories to produce commercial fuels, synthetic rubbers, plastics, and additional chemicals. Oil refineries were originally placed near the oil fields partly because natural gas, which could not then be economically transported long distances, was available to fuel the highly energy-intensive refining process. But since 1950, crude oil has bwn transported by tankers and oleoducts to local refineries for strategic reasons. 

Source http //synerjy.com/SITE%20PAGES/Fuel%20Heat%20Values %20Page.htm solids liq gas 

Type of Fuel Softwood (kiln dried -13% Moisture) Hard- wood (kiln dried -8% Moisture) Wood Pellets Natural Gas Electricity Firewood (Seasoned -20% Moisture) Switchgrass (Ovendried) Bituminous Coal Shelled Com (-15% Moisture) No. 2 Fuel Oil No. 6 Fuel Oil Propane 

Fuel Coal Coal Pet Coke/ Waste Oil Vacuum Residue Coal Lignite  

Nearly all metal contained in crude oil is either chemically bound with asphaltene type structures or associated with asphaltenes (1000-10,000 daltons). It is necessary to remove these metals to prevent contamination of catalysts. 

The present process uses a solvent like hexane or pentane to flocculate the asphaltenes and is relatively expensive. UF can retain the metal asphaltene complexes while passing virtually all other crude oil fractions. Again, the flux is low due to high viscosity. However, an inorganic membrane operating at 330°C on a 10% asphaltene feed produced a permeate with less than 0.5% asphaltenes. 

The removal of the carbon-forming asphaltenes and catalyst-fouling metals also reduces the process costs for desulfurization of fuel oil. 

These same factors influence the spread among the different sources of oil. For example, in the last several years, the price spread between wn and Brent crude has varied. In 2012, there was some concern about the European financial system and political unrest in the Mid-East. During this time. 

Fundamentals of Industrial Chemistry Pharmaceuticals, Polymers, and Business, First Edition. John A. Tyrell. 2014 John Wiley Sons, Inc. PnbUshed 2014 by John Wiley Sons, Inc. 

We can start to get a sense of the chemistry by considering how n-heptane might be cracked. It is a radical mechanism and by heat, enough energy is supplied to break bonds. 

By breaking the C3-C4 bond, we create a propyl radical and a butyl radical. The propyl radical can decompose to propylene and a hydrogen radical. The butyl radical can form ethylene and an ethyl radical. The formed 

The raffinate includes isobutene, also known as isobutylene, as the largest component followed by 1-butene and then 2- butene, both cis and trans isomers. Saturated butanes, n-butane and isobutane, are also present. 

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Crude oils have physical and chemical characteristics that vary widely from one production field to another and even within the same field. 

Figure 1.1 illustrates the diversity of products derived from petroleum classified according to their distillation ranges and number of carbon atoms. From one crude to another, the proportions of the recovered fractions vary widely. A good illustration is the gasoline fraction (one of the most economically attractive) a crude from Qatar gives about 37 per cent by volume whereas a Boscan crude oil only yields 4.5%. 

Crude oils are mixtures of pure components, but these are extremely numerous and the difficulty to describe the different fractions increases with the number of carbon atoms. 

Chapter 1. COMPOSITION OF CRUDE OILS AND PETROLEUM PPODUCTS... 

Chapter 1. Composition of Crude Oils and Petroleum Products... 

The rings most frequently encountered in crude oils are those having five or six carbon atoms. In these rings, each hydrogen atom can be substituted by a paraffinic alkyl chain that is either a straight chain or branched. 

Chapter 1. COMmsmON OF CRUDE OILS AND PETROLEUM PRODUCTS... 

Chapter 1. COMPOSITION Of CRUDE OILS AND PETROLEUM PRODUCTS 7... 

There are little or no olefins in crude oil or straight run (direct from crude distillation) products but they are found in refining products, particularly in the fractions coming from conversion of heavy fractions whether or not these processes are thermal or catalytic. The first few compounds of this family are very important raw materials for the petrochemical Industry e.g., ethylene, propylene, and butenes. 

Normally absent or in trace amounts in crude oil, products of conversion processes such as diolefins, acetylenes, etc., are encountered. Table 1.4 gives the physical properties of some of them. Noteworthy is 1-3 butadienerC ( l)... 

Sulfur is the heteroatom most frequently found in crude oils (see Table 1.5). Sulfur concentrations can range from 0.1 to more than 8 weight percent moreover, this content is correlated with the gravity of the crude oil and, therefore, its quality (light or heavy). 

Chapter 1. COMPOSmON OF CRUDE OILS AND PEmOLEUM PRODUCTS... 

Crude oils generally contain less oxygen than sulfur (Table 1,5). Even though it is not abundant, oxygen can play a consequential role in particular, it is responsible for petroleum acidity. Oxygen is found in the following compounds ... 

In crude oil, nitrogen is found mostly in fractions boiling over 250°C and is particularly concentrated in resins and asphaltenes. Nitrogen takes the following forms / to). ... 

Crude oil topped at 260°C or atmospheric residue or vacuum residue... 

Other techniques such as X-ray diffusion or small angle neutron diffusion are also used in attempts to describe the size and form of asphaltenes in crude oil. It is generally believed that asphaltenes have the approximate form of very flat ellipsoids whose thicknesses are on the order of one nanometer and diameters of several dozen nanometers. 

Fractionation and Elemental Analysis of Crude Oils and Petroleum Cuts... 

Crude oils form a continuum of chemical species from gas to the heaviest components made up of asphaltenes it is evidently out of the question, given the complexity of the mixtures, to analyze them completely. In this chapter we will introduce the techniques of fractionation used in the characterization of petroieum as well as the techniques of elemental analysis applied to the fractions obtained. 

Chaptar 2. FRACTIONATION AND ELEMENTAL ANALYSIS OF CRUDE OILS AND PETROLEUM CUTS... 

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