Petroleum, heavy oils from

When petroleum occurs in a reservoir that allows the crude material to be recovered by pumping operations as a free-flowing dark- to light-colored liquid, it is often referred to as conventional petroleum. Heavy oils comprise the other types of petroleum they differ from conventional petroleum in being much more difficult to recover from subsurface reservoirs. The definition of heavy oils is usually based on the API gravity or viscosity value, and the definition is quite... 

Briefly, the asphaltene fraction of crude oil is that fraction which is precipitated by the addition of a large excess of a low-boiling liquid hydrocarbon (usually n-heptane) (Chapter 3). On the other hand, resins are those materials which remain soluble in the pentane but will be adsorbed by a surface-active material such as fuller s earth, while the oils fraction is soluble in pentane but is not adsorbed from the pentane solution by any surface-active material. The asphaltic fraction of any petroleum, heavy oil, or residuum is usually a combination of the asphaltene and resin fraction and, in many instances, may constitute a large portion of a heavy oil or, especially, of a residuum. 

Heavy oils derived from petroleum were separated by using the method developed by the USBM-API (5) Project 60 and analyzed by means of mass spectroscopy. The procedure used for separation and characterization of petroleum heavy oil was adopted to study heavy oil from coal liquids derived from Char-Oil-Energy-Development (COED) Syncrude from Utah coal (6) and western Kentucky coal (7) and Synthoil from West Virginia coal (i, 8). 

The amount of light fractions can be very different for oils from different oil wells. For example, it can be under 20% for some heavy oils from Alberta (Canada) and over 60% for some light oils form western Siberia (Russia). Typical analysis of a Canadian petroleum from oil wells in McMurray resulted in the following fractions ... 

Determination of the asphaltene fraction of petroleum has been investigated for most of this century (5-11), and therefore the art is not new. However, it is now generally accepted that asphaltenes are, by definition, a solubility class that is precipitated from petroleum, heavy oil, and bitumen by the addition of an excess of liquid hydrocarbon (11), The procedure not only dictates asphaltene yield but can also dictate the quality of the fraction (12-16), In fact, the very method of asphaltene separation is a prime example of the disturbance of the system by the addition of an external agent. Thus, during deasphalting, the dispersibility (or compatibility) of the asphaltenes in the system is changed. The... 

In summary, the separation of asphaltenes from petroleum, heavy oil, and bitumen is not only a function of the amount of added diluent but also a function of the type and composition of the diluent (14, 22, 24). 

Solids production and control remain a high priority for the petroleum industry. In conventional oil and gas operations, control of produced solids is a primary focus. In recovery of heavy oil from unconsolidated reservoirs, production and handling of large quantities of produced solids present special challenges, both in the removal of solids from the wellbore and their subsequent disposal. The rapid expansion of horizontal well applications has led to some unique approaches to solids handling and is likely to lead to new technical advances as the horizontal drilling and completions technology continues to advance. 

FIGURE 11.2 Fraction scheme for petroleum, heavy oil, and bitumen—pyridine-soluble tars from coal can be fractionated in a similar manner. (From Speight, J.G., The Chemistry and Technology of Petroleum, 4th edn., Taylor Francis Group, Boca Raton, FL, 2007.)... 

Heavy cmde oil is widely distributed, and it is difficult to estimate reserves separate from normal cmde oil reserves or from tar sands deposits. Estimates of petroleum reserves frequendy include a large heavy oil component, which can only be produced at significantly higher cost than light oil. 

Petroleum refining, also called petroleum processing, is the recovery and/or generation of usable or salable fractions and products from cmde oil, either by distillation or by chemical reaction of the cmde oil constituents under the effects of heat and pressure. Synthetic cmde oil, produced from tar sand (oil sand) bitumen, and heavier oils are also used as feedstocks in some refineries. Heavy oil conversion (1), as practiced in many refineries, does not fall into the category of synthetic fuels (syncmde) production. In terms of Hquid fuels from coal and other carbonaceous feedstocks, such as oil shale (qv), the concept of a synthetic fuels industry has diminished over the past several years as being uneconomical in light of current petroleum prices. 

Heavy oil is another type of petroleum, different from conventional petroleum insofar as the flow properties are reduced. A heavy oil is much more difficult to recover from the subsurface reservoir. These materials have a high viscosity and low API gravity relative to the viscosity and API gravity of conventional petroleum (Fig. 1) (3,4), and recovery of heavy oil usually requires thermal stimulation of the reservoir. 

In a general sense, however, the term heavy oil is often appHed to a petroleum that has a gravity <20° API. The term heavy oil has also been arbitrarily used to describe both the heavy oil that requires thermal stimulation for recovery from the reservoir and the bitumen in bituminous sand (also known as tar sand or oil sand) formations, from which the heavy bituminous material is recovered by a mining operation. Extra heavy oil is the subcategory of petroleum that occurs in the near-soHd state and is incapable of free flow under ambient conditions. The bitumen from tar sand deposits is often classified as an extra heavy oil. 

The principal sources of feedstocks in the United States are the decant oils from petroleum refining operations. These are clarified heavy distillates from the catalytic cracking of gas oils. About 95% of U.S. feedstock use is decant oil. Another source of feedstock is ethylene process tars obtained as the heavy byproducts from the production of ethylene by steam cracking of alkanes, naphthas, and gas oils. There is a wide use of these feedstocks in European production. European and Asian operations also use significant quantities of coal tars, creosote oils, and anthracene oils, the distillates from the high temperature coking of coal. European feedstock sources are 50% decant oils and 50% ethylene tars and creosote oils. 

The Chemistry and Technology of Petroleum, James G. Speight The Desulfurization of Heavy Oils and Residua, James G. Speight Catalysis of Organic Reactions, edited by William R. Moser Acetylene-Based Chemicals from Coal and Other Natural Resources, Robert J. Tedeschi... 

Sylvestrene nitrosochloride, CjoHj,. NOCl, is prepared from pure sylvestrene, regenerated from the dihydrochloride in the following manner Four volumes of the terpene are dissolved in six of amyl nitrite and five volumes of strong hydrochloric acid are added, with constant shaking. The heavy oil which separates is shaken with a little ethyl alcohol, when it solidifies, and can be purified by dissolving it in chloroform and precipitating it with petroleum ether. It is finally recrystallised from methyl alcohol, when it melts at 106° to 107°. 

The solution was heated on a steam bath for 6 hours. After cooling, the whole was poured into water and the oil extracted well with ether, the ether solution was discarded and the aqueous solution neutralized with 1 N sulfuric acid. A heavy oil separated which was taken into ether, washed with water, bicarbonate solution and again with water. After drying, the ether was removed to give a thick oil which solidified on standing (34.6 grams). After recrystallization from an ether-petroleum ether mixture it formed needles, MP 108°-112°C. 

As one more common example of liquid fuels present reference may be drawn to liquified petroleum gas (LPG) or bottled gas or refinery gas. This fuel is obtained as a by-product during the cracking of heavy oils or from natural gas. It is dehydrated, desulfurized and traces of odours organic sulfides (mercaptans) are added in order to identify whether a gas leak has occurred. Supply of LPG is carried out under pressure in containers under different trade names. It consists of hydrocarbons of great volatility such that they can occur in the gaseous state under atmospheric pressure, but are readily liquifiable under high pressures. The principal constituents of LPG are n-butane, iso-butane, butylene and propane,... 

Residual products (No. 6 fuel oil, bunker C oil) these products have little (usually, no) ability to evaporate. When spilled, persistent surface and intertidal area contamination is likely with long-term contamination of the sediment. The products are very viscous to semisolid and often become less viscous when warmed. They weather (oxidize) slowly and may form tar balls that can sink in waterways (depending on product density and water density). They are highly adhesive to soil. Heavy oil, a viscous petroleum, and bitumen from tar sand deposits also come into this category of contaminant. 

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