Asphalt production

ELASTOPffiRS,SYNTHETic-POLYcm.OROPRENE Elastop rs, SYNTHETIC-ETHYLENE-PROPYLENE-DIENE RUBBER). Tires, hoses, belts, molded and extmded goods, and asphalt products consume ca 80% of the reclaimed mbber manufactured. Typical properties of reclaimed mbbers are shown in Table 5. 

Cmde oil containing about 30% asphalt can be refined completely in an atmospheric unit to an asphalt product. However, most cmde oil cannot be distilled satisfactorily to an asphalt product at atmospheric pressure because of the presence of substantial proportions of high boiling gas oil fractions. Thus, as a supplement to the atmospheric process, a second fractionating tower (a vacuum tower) is added (Fig. 1). 

Many agents have been proposed and patented including copper sulfate (34), zinc chloride (35), ferric chloride (36), aluminum chloride (36), and phosphoms pentoxide (37) ferric chloride, zinc chloride, and phosphoms pentoxide have been most widely used. The addition of these agents may vary from 0.1 to 3%, depending upon the feedstock and the desired characteristics of the product (Table 5) and all asphalt feedstocks do not respond to catalysts in the same way. Differences in feedstock composition are important qualifiers in determining the properties of the asphalt product. The important softening point-penetration relationship, which describes the temperature susceptibiUty of an asphalt, also varies with the source of the feedstock. Straight-reduced, air-blown, and air-blown catalytic asphalts from the same cmde feedstock also vary considerably. 

Thermal Asphalt. Thermal asphalt products are in low supply because the thermal process has been virtually replaced by catalytic cracking processes. Thermal pitches, because of their high viscosity temperature susceptibiHty, are very hard at ordinary temperatures (Table 9), but become quite... 

Liquid Asphalt. Liquid asphalt products comprise cutback asphalts and emulsions. A number of grades of different viscosities are available, which permit appHcation from ambient temperatures to 150°C. The lower viscosity products are used for dust-laying purposes and as tack coats, prior to laying asphalt surface courses. The heavier grades are used for mix-in-place road mixes. 

If the injected acid itself contains iron (III), a precipitation of the asphaltic products can occur when it comes in contact with certain crude oils. This leads to practically irreversible damage of the zone treated. The amount of precipitate generally increases with the strength and concentration of the acid. Certain organic sulfur compounds, such as ammonium thioglycolate, mercaptoethanol, cysteamine, thioglycerol, cysteine, and thiolactic acid [581], can reduce the iron (HI). 

PAHs, more correctly known as polyaromatic compounds (PACs) are common in the human environment, e.g, the exhaust of diesel engines, bitumen and asphalt production. Some of the PAHs are genotoxic and carcinogenic (e.g benz(a)pyrene). 

Over the years, the refinery has produced a range of petroleum products including liquid petroleum gas, gasoline, chemicals, solvents, distillate fuels, gas oils, lubricating oils, greases, asphalt products, and bunker fuels. The primary products of the refinery are currendy gasoline, jet fuel, and diesel. Minor products include coke, sulfur, naphtha, and fuel oil. The refinery processes approximately 200,000 barrels... 

Exposure limits Potential occupational carcinogen. No individual standards have been set however, as a constituent in coal tar pitch volatiles and asphalt products, the following exposure limits have been established (mg/m ) NIOSH REL TWA 0.1 (cyclohexane-extractable fraction), IDLH 80 OSHA PEL TWA 0.2 (benzene-soluble fraction) ACGIH TLV TWA 0.2 (benzene... 

Asphalt feedstock (flux) is contacted with hot air at 200-280°C (400-550°F) to obtain desirable asphalt product. Both batch and continuous processes are in operation at present, but the batch process is more prevalent because of its versatihty. Nonrecoverable catalytic compounds include copper sulfate, zinc chloride, ferric chloride, aluminum chloride, phosphorus pentoxide, and others. The catalyst does not normally contaminate the process water effluent. 

Topping Includes topping, catalytic reforming, asphalt production, or lube oil manufacturing processes, but excludes any facdity with cracking or thermal operations. 

The chemical composition of vapors and fumes from asphalt products is variable and depends on the crude petroleum source, type of asphalt, temperature, and extent of mixing. Therefore, the adverse effects from asphalt may also vary considerably depending on the source of exposure. 

Uses. Used mineral-hased crankcase oil is mixed with other oils to produce cutting oils or other lubricating oils. It is incinerated for energy in oil burners in homes, industrial steam boilers, municipal incinerators, and rotary cement kilns. It is also used in asphalt production. 

At a brownfield site in Illinois, the biopile process was used with air sparging to treat soils contaminated with petroleum hydrocarbons and by-products of asphalt production. Treatment at the 13- to 15-acre site occurred for one year, and site closure was achieved as a result of the process. The project cost was approximately 100,000, which was significantly less than the estimated cost of landfilling the contaminated soil (D21948R, pp. 3, 5). 

By 1911 the tonnage of domestic petroleum asphalts exceeded the importations of Trinidad and Bermudez asphalts. Starting about 1920, and coincident with the rapid expansion in rural road building, the production of petroleum asphalt has rapidly increased, as shown by Figure 1, so that it exceeded 9,000,000 tons in 1949. The ratio of petroleum to native and rock asphalt production in 1949 was approximately 8 to 1 (186). 

Figure 1. U. S. Asphalt Production by Decades (Millions of Short Tons)...

The early methods for determining wax in asphaltic products employed high temperature distillation, vigorous chemical treatment, or selective adsorption to eliminate interference of asphaltenes and resins before the wax could be determined by crystallization methods (2). The Holde method, involving destructive distillation of sample to coke, was best known and most widely used. Since solid paraffins may be decomposed or altered by such vigorous treatment, the reliability of the results was in doubt. A new ap-... 

Although deasphalting offers a form of desulfurization of heavy feedstocks, there is ( as might be expected) a downside to the application of the process in this manner or as a pretreatment step. Deasphalting removes potentially high-value material that might be otherwise converted to liquid products with the need to dispose of a product that might not be suitable for asphalt production. 

Nevertheless, deasphalting is often considered as an alternative to hydrocracking but the economics of removing a portion of the feed stream and diverting it to asphalt production requires careful consideration. 

A previous chapter (Chapter 7) has dealt with the tried-and-true processes that are used in refineries and that were developed for conversion of residua as an option to asphalt production (Figure 8-1). These processes (visbreaking, cok-... 

The raffinate phase containing asphalt and a small amount of solvent flows from the bottom of the rotating disc contactor to the asphalt mix heater. The hot, two phase asphalt mix from the heater is flashed in the asphalt mix flash tower where solvent vapor is taken overhead, condensed, and collected in the low pressure solvent receiver. The remaining asphalt mix flows to the asphalt stripper where the remaining solvent is stripped overhead with superheated steam. The asphalt stripper overhead vapors are combined with the overhead from the deasphalted oil stripper, condensed, and collected in the stripper drum. The asphalt product is pumped from the stripper and is cooled by generating low pressure steam. 

Electric Utility Development Operation Construction, Heavy Civil Engineering Cement, Stone Asphalt Production Road Bridge Holdings Water Utility... 

Procurement guidelines for materials such as rubberized asphalt, products made from reprocessed rubber, and rubber railroad crossings are all potential means of helping to encourage these uses of scrap tires. 

Plasticizer, environmental decomposition of trichloroethylene Solvents, cleaners Wood preservatives, insect repellants, cosmetics Tar removers, waxes, degreasers Tar removers, waxes, degreasers Asphalt products, shampoos, skin treatments... 

Benzo [a] anthracene Cigarette smoke, asphalt products, petroleum combustion... 

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