Evaporation Bitumen

Substances that were naturally sticky included the resinous exudations of certain trees, notably the pines, egg white, some waxes, and the so-called mineral bitumen found oozing from the ground in various parts of the world. This latter substance represents remnants of former oil deposits that have escaped to the surface as a result of earth movements and erosion, the lighter fractions having long ago escaped by evaporation. Bitumen is, therefore, in reality a product of the decomposition of organic matter. 

A number of types of bituminous material exist and terminology is still somewhat confusing. The term bitumens in its widest sense includes liquid and solid hydrocarbons but its popular meaning is restricted to the solid and semisolid materials. The bitumens occur widely in nature and may be considered to be derived from petroleum either by evaporation of the lighter fraction under atmospheric conditions or by a deeper seated metamorphism. The purer native bitumens are generally known as asphaltites and include Gilsonite, extensively used for moulding, which occurs in Utah. 

These are semisolid or solid substances formed in nature from crude oils after the volatile components have evaporated and the remainder has undergone oxidation and polymerization. They are also referred to as bitumens, waxes, and pitch. These materials are believed to consist of mixtures of complex organic molecules of high molecular weight. As with crude oils, which contain thousands of different chemical compounds, an exact chemical analysis for identification and composition is impractical to perform on the solid deposits of petroleum. 

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. 

Evaporation. Maxima in the approximate range C20-C30 are partly the result of evaporation of lower homologs during long access to the atmosphere. This process is inherent in that of inspissationthrough which deposits of bitumen are conventionally accounted for, and has been implicated in hatchettite formation (7). 

The extraction is finished when the thimble holding the substance loses its brown colour and becomes completely decolorised, this requiring 1-2 hours. Excessively long extraction is to be avoided, since an appreciable part of the rubber would then be dissolved. The pyridine solution is evaporated in a tared porcelain dish on an oil-bath, the residue representing the bitumen, tar and pitch of the original substance. 

Extraction. The powdered samples (ca. 60 g) were extracted sequentially with 100 ml MeOH, 100 ml MeOH/CH2Cl2 (1/1, v/v, x2) and with 75 ml CH2G2 (x5) using ultrasonication and centrifugation. The supernatants were combined and the bitumens were obtained after rotary evaporation of the solvent at 30°C. 

Oil-wet materials, sand, and clay, separated from either oil or water layers, are washed with the solvent or diluent until they are free of bitumen and the residual solvent is stripped from the mineral matter with steam. The mineral matter is clean and is sent to waste or used as fill without danger of spontaneous combustion, or it is used in cement manufacture. The aqueous phases condensed from such stripping and from the decanter of the azeotropic system has so little solvent, in hundredths of a percent, that it is neglected. It evaporates readily in open storage. This distilled water is used for any suitable purpose. 

Bitumen from the core samples was extracted with boiling toluene, using a modified Soxhlet extractor (12), and the solution was filtered and evaporated as described for heavy oils. 

Heavy-Oil Evaporation Dehydrator (HOE V-3). Figure B.5 illustrates the process flow schematics for the HOE unit. This horizontal vessel can serve as either an alternative to the DPET (should the oil-bitumen-rich stream exiting the FWKO contain less than 10% water) or as a secondary treater to the DPET. The HOE unit is designed to process an emulsion composed of oil-bitumen (70%), water (10%), and diluent (20%) at a combined rate of 460 L/h (70 barrels per day) for raw oil-bitumen of API gravity... 

The treated oil-bitumen is collected in the bottom of the vessel, while the vapors exit at the top. The contact temperature in the vessel is approximately 150 C (300 T), and the total area of the three trays is approximately 3.34 m (36 sq ft). The treated oil, which should contain less than 0.5% (v/v) water, is then pumped from the bottom of the evaporator, fan-cooled and sent to the treated-oil storage tank (T-2). The water-diluent vapors are also fan-cooled, sent to an accumulator, and then transferred to a gravity separator for diluent recovery. Water is sent to the produced-water tank (T-3) before being processed through the IGF unit. 

Asphalt A brown or black tarlike variety of bitumen obtained by evaporating petroleum. 

The bituminization process is performed basically by adding a concentrated waste slurry or even a predried waste mixture to the molten bitumen. Residual water is evaporated and the solids are evenly distributed in the bitumen. After solidification a homogeneous product is obtained. Figure 11.23 shows a flow sheet of a screw extruder plant for bituminization Figure 11.24 is a photograph of the screw extruder evaporator,... 

Asphalt Asphaltum mineral pitch Judean pitch bitumen. Bituminous substance resulting from petroleum by evaporation of lighter hydrocarbons and partial oxidation of the residue. Occurs in West Indies (chiefly Trinidad) Venezuela, Dead Sea, Switzerland, etc. 

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