Petroleum vacuum residuum

Vacuum residuum a residuum (. v.) obtained by distillation of a crude oil under vacuum (reduced pressure) that portion of petroleum that boils above a selected temperature such as 510°C (950°F) or 565°C (1050°F). 

Figure 7. Comparison of molecular weight distribution off o) coal asphaltenes and Jobo petroleum asphaltenes (-------) vacuum residuum and (%) atmo-...

SYNS CONDENSATES (PETROLEUM), VACUUM TOWER (9CI) VACUUM RESIDUUM... 

A residuum, often shortened to resid, is the residue obtained from petroleum after nondestmctive distillation has removed all the volatile materials. The temperature of the distillation is usually below 345°C because the rate of thermal decomposition of petroleum constituents is substantial above 350°C. Temperatures as high as 425°C can be employed in vacuum distillation. When such temperatures are employed and thermal decomposition occurs, the residuum is usually referred to as pitch. By inference, the name is used in the same manner as when it refers to the nonvolatile residue from the thermal decomposition of coal tar (3). 

The term tar sands is a misnomer tar is a product of coal processing. Oil sands is also a misnomer but equivalent to usage of "oil shale." Bituminous sands is more correct bitumen is a naturally occurring asphalt. Asphalt is a product of a refinery operation, usually made from a residuum. Residuum is the nonvolatile portion of petroleum and often further defined as atmospheric (bp > 350° C) or vacuum (bp > 565° C). For convenience, the terms "asphalt" and "bitumen" will be used interchangeably in this article. 

Residua are the dark-colored nearly solid or solid products of petroleum refining that are produced by atmospheric and vacuum distillation (Figure 11.1 Chapter 3). Asphalt is usually produced from a residuum and is a dark brown to black cementitious material obtained from petroleum processing that contains very high-molecular-weight molecular polar species called asphaltenes that are soluble in carbon disulfide, pyridine, aromatic hydrocarbons, and chlorinated hydrocarbons (Chapter 3) (Gruse and Stevens, 1960 Guthrie, 1967 Broome and Wadelin, 1973 Weissermel and Arpe, 1978 Hoffman, 1983 Austin, 1984 Chenier, 1992 Hoffman and McKetta, 1993). 

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