Asphalt refinery

The separation of the components of crude oil into useable products is known as refining. Each of the crude oil fractions finds its way into consumer products. A typical list of fractions is gasoline, kerosene and fuel oil, gas oil, wax distillate, and bottoms or asphaltics. Refineries must be designed to handle... 

The bituminous extracts may also be separated into solid and oily materials in a manner similar to the fractionation of petroleum, tar sand bitumen (natural asphalt), refinery (manufactured) asphalts, and petroleum residua (Figure 11.2). As already noted (see also p. 183), the term bitumen is more correctly used for the natural asphalts that occur in various parts of the world and an artifact of the thermal process is often called tar or pitch (Speight, 2007). 

Several years ago, I was working for an asphalt refinery in Corpus Christi, Texas. This refinery collected all their contaminated steam condensate streams from reflux drums and from a vacuum tower hot-well system. Without even steam stripping, the collected condensate was recycled back to the steam boiler. It s true only low-pressure (100-psig) steam was generated. It s true the steam so generated was not used in a turbine or in any chemical process. But on the other hand, they had been doing this for 20 years without any ill effects. 

During storage, sediments decant with the water phase and deposit along with paraffins and asphalts in the bottoms of storage tanks as thick sludges or slurries (BS W). The interface between the water-sediment and the crude must be well monitored in order to avoid pumping the slurry into the refinery s operating units where it can cause serious upsets. 

Simple conventional refining is based essentially on atmospheric distillation. The residue from the distillation constitutes heavy fuel, the quantity and qualities of which are mainly determined by the crude feedstock available without many ways to improve it. Manufacture of products like asphalt and lubricant bases requires supplementary operations, in particular separation operations and is possible only with a relatively narrow selection of crudes (crudes for lube oils, crudes for asphalts). The distillates are not normally directly usable processing must be done to improve them, either mild treatment such as hydrodesulfurization of middle distillates at low pressure, or deep treatment usually with partial conversion such as catalytic reforming. The conventional refinery thereby has rather limited flexibility and makes products the quality of which is closely linked to the nature of the crude oil used. 

However, simplification of the refining procedure is not always the end result. IncompatibiUty of different cmde oils, which can occur if, for example, a paraffinic cmde oil is blended with a heavy asphaltic oil, can cause sediment formation ia the unrefined feedstock or ia the products, thereby complicating the refinery process (5). 

The early developments of solvent processing were concerned with the lubricating oil end of the cmde. Solvent extraction processes are appHed to many usefiil separations in the purification of gasoline, kerosene, diesel fuel, and other oils. In addition, solvent extraction can replace fractionation in many separation processes in the refinery. For example, propane deasphalting (Fig. 7) has replaced, to some extent, vacuum distillation as a means of removing asphalt from reduced cmde oils. 

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. 

Petroleum asphalts, compared to native asphalts, are organic with only trace amounts of inorganic materials. They derive their characteristics from the nature of their cmde origins with some variation possible by choice of manufacturing process. Although there are a number of refineries or refinery units whose prime function is to produce asphalt, petroleum asphalt is primarily a product of integrated refineries (Fig. 1). Cmdes may be selected for these refineries for a variety of other product requirements and the asphalt (or residuum) produced may vary somewhat in characteristics from one refinery-cmde system to another and even by cut-point (Table 2) and asphalt content (Fig. 2) (5,6). The approximate asphalt yields (%) from various cmde oils are as follows ... 

Industrial-Commercial-Institutional Steam Generating Units Incinerators Portland Cement Plants Nitric Acid Plants Sulfuric Acid Plants Asphalt Concrete Plants Petroleum Refineries... 

Sulfuric acid plants Asphalt concrete plants Petroleum refineries ... 

There is a wide range of conversion levels. The term maximum conversion type has no precise definition but is often used to describe a level of conversion, where there is no net fuel oil manufactured. A fuel products refinery with specialities may manufacture lubricating oils, asphalts, greases, solvents, waxes and chemical feed stocks in addition to the primary fuel products. The number and diversity of products will naturally vary from one refinery to another. Refineries produce chemical feed stocks for sale to the chemical affiliates and do not have responsibility for the manufacture of chemical products directly. Both operations may be carried out at the same physical location but the corporate product responsibilities are usually separate. 

Joden, m.pl. Jews Metal.) refinery scraps, -dombeere, /. jujube, zizyphus. -harz, n. = Judenpech. -kirsche,/. alkekengi Phyaalis). -pech, n. Jew s pitch (asphalt). -pilz, -schwamm, m. a species of Boletus. 

Refineries produce more than 2,000 products, but most of these are very similar and differ in only a few specifications. The mam products, with respect to volume and income, are liquefied petroleum gases (LPG), gasolines, diesel fuels, jet fuels, home heating oils (No. 1 and No. 2), and heavy heating oils (No. 4, No. 5, No. 6, and bunker fuel oil). Some refineries also produce asphalts and petroleum coke. 

Bulk Plants, Distribution and Marketing Terminals store and distribute the finished products from the refineries and gas plants. Typically these facilities handle gasoline, diesel, jet fuels, asphalts, and compressed propane or butane. 

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... 

Typical refinery producfs include (1) nafural gas and liquefied petroleum gas (LPG), (2) solvent naphtha, (3) kerosene, (4) diesel fuel, (5) jet fuel, (6) lubricating oil, (7) various fuel oils, (8) wax, (9) residua, and (10) asphalt (Chapter 3). A single refinery does nof necessarily produce all of fhese producfs. Some refineries are dedicated to particular products (e.g., the production of gasoline or the production of lubricating oil or the production of asphalt). However, the issue is that refineries also produce a variety of waste products (Table 4.1) that must be disposed of in an enviromnentally acceptable manner. 

The importance of residua and asphalt to the environmental analyst arises from spillage or leakage in the refinery or on the road. In either case, the properties of... 

The residua from which asphalt are produced, once considered the garbage of a refinery, have little value and little use other than as a road oil. In fact, the development of delayed coking (once the so-called refinery garbage can ) was with the purpose of converting residua to liquids (valuable products) and coke (fuel). 

Deasphalting the removal of the asphaltene fraction from petrolenm by the addition of a low-boiling hydrocarbon liqnid snch as n-pentane or n-heptane more correctly, the removal asphalt (tacky, semisolid) from petroleum (as occurs in a refinery asphalt plant) by the addition of liqnid propane or liquid butane under pressnre. 

The developer claims that the technology is applicable for remediation at refineries, wood treating sites, old town gas plants, and at sites where weathered hydrocarbons contain a substantial fraction of polar asphaltic components. 

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