Asphalt manufacture

Vacuum distillation of the atmospheric residue complements primary distillation, enabli r.ecoyery of heavy distillate cuts from atmospheric residue that will un r o further conversion or will serve as lube oil bases. The vacuum residue containing most of the crude contaminants (metals, salts, sediments, sulfur, nitrogen, asphaltenes, Conradson carbon, etc.) is used in asphalt manufacture, for heavy fuel-oil, or for feed for others conversion processes. 

Since the early 1900s most of the asphalts produced from the refining of petroleum have been used primarily in paving and roofing appHcations. The advent of motorized transportation led to increased asphalt manufacture from petroleum in order to provide binders for hard-surfaced pavements. 

Asphalt Manufacture Saleable asphalts are produced from the residua of selected crudes. The residuum itself may be sold as straight reduced cuts to make it easier to handle, producing the so called cut-back asphalts. Another variation is air blown or oxidized asphalts for improved tenacity, greater resistance to weathering, and decreased brittleness. Emulsified asphalts are made for application at relatively low temperatures. 

Venturi scrubbers have been applied to control PM emissions from utility, industrial, commercial, and institutional boilers fired with coal, oil, wood, and liquid waste. They have also been applied to control emission sources in the chemical, mineral products, wood, pulp and paper, rock products, and asphalt manufacturing industries lead, aluminum, iron and steel, and gray iron production industries and municipal solid waste incinerators. Typically, Venturi scrubbers are applied where it is necessary to obtain high collection efficiencies for fine PM. Thus, they are applicable to controlling emission sources with high concentrations of submicron PM. 

Figure 11.2. Asphalt manufacture including air blowing (Speight, 1992, 1999, and references cited therein).

Industrial surfactants find uses in almost every industry, from asphalt manufacturing to carpet fibers, from pulp and paper production to leather processing. Examples of the types of chemicals used as surfactants are fatty alcohol sulfates, alkanolamides, alkoxylates, sulfosuccinates, amines, quaternaries, phosphate esters, acid esters, blockcopolymers, betaines, imidazolines, alkyl sulfonates, etc. 

One obvious method of cleaning the feed is to remove asphaltic material (asphaltenes plus resins) using a solvent such as propane in a deasphalting unit. The resulting deasphalted oil has less metals than the original feedstock but coke formation and catalyst deactivation are not completely eliminated. The byproduct stream is usually only acceptable as a raw material for asphalt manufacture. Even then, the asphaltic by-product may be unsuitable for a specification grade asphalt and require disposal by other means. 

Recently, asphalt has grown to be a valuable refinery product. In the post-1980 period, a shortage of good quality asphalt has developed. This is, in no short measure, because of the tendency of refineries to produce as much liquid fuels (e.g., gasoline) as possible. Thus, residua that would have once been used for asphalt manufacture are now being used to produce liquid fuels (and coke). 

Ceramics, cement and asphalt manufacturing works (ISBN 1 85 112290 7). Chemical works coatings (paints and printing inks) manufacturing works (ISBN 1 85 112291 5). 

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