Upgrading properties of asphalts with wax (ExxonMobil)

CATEGORY: ASPHALT
Upgrading properties of asphalts with wax (ExxonMobil)

Type	Patent
Inventor	Pavel Kriz
Inventor	Katherine Lynn Sokol
URL	Free Full Text Source:  http://www.google.com/patents/US20140076777
Extra	BACKGROUND Asphalt is one of the world's oldest engineering materials, having been used since the beginning of civilization. Asphalt is a strong, versatile and chemical-resistant binding material that adapts itself to a variety of uses. For example, asphalt is used to bind crushed stone and gravel into firm tough surfaces for roads, streets, and airport runways. Asphalt, also known as pitch, can be obtained from either natural deposits, or as a by-product of the petroleum industry. Natural asphalts were extensively used until the early 1900s. The discovery of refining asphalt from crude petroleum and the increasing popularity of the automobile served to greatly expand the asphalt industry. Modern petroleum asphalt has the same durable qualities as naturally occurring asphalt, with the added advantage of being refined to a uniform condition substantially free of organic and mineral impurities. Most of the petroleum asphalt produced today is used for road surfacing. Asphalt is also used for expansion joints and patches on concrete roads, as well as for airport runways, tennis courts, playgrounds, and floors in buildings. Another major use of asphalt is in asphalt shingles and roll-roofing which is typically comprised of felt saturated with asphalt. The asphalt helps to preserve and waterproof the roofing material. Other applications for asphalt include waterproofing tunnels, bridges, dams and reservoirs, rust-proofing and sound-proofing metal pipes and automotive under-bodies; and sound-proofing walls and ceilings. The raw material used in modern asphalt manufacturing is petroleum, which is naturally occurring liquid bitumen. Asphalt is a natural constituent of petroleum, and there are crude oils that are almost entirely asphalt. The crude petroleum is separated into its various fractions through a distillation process. After separation, these fractions are further refined into other products such as asphalt, paraffin, gasoline, naphtha, lubricating oil, kerosene and diesel oil. Since asphalt is the base or heavy constituent of crude petroleum, it does not evaporate or boil off during the distillation process. Asphalt is essentially the heavy residue of the oil refining process. U.S. Patent Application Publication 2010/0319577 describes asphalt modifiers for “warm mix” applications. An asphalt is combined with 0.2. wt % to 10 wt % of an additive package. The additive package is described as including from 10-60 wt % of an amine or modified amine surfactant and from 20-90 wt % of a rheology modifying component corresponding to a mixture of a wax and a vegetable or petroleum resin.
Assignee	Exxonmobil Research And Engineering Company
Patent Number	US20140076777 A1
Issue Date	Mar 20, 2014
Abstract	Methods are provided for upgrading the quality of an asphalt containing wax. This can include base asphalts that naturally contain elevated levels of wax, such as base asphalts with a wax content of at least 3.0 wt %. Additionally or alternately, this can include a base asphalt containing subsequently added wax. Wax generated at a refinery can be added to an asphalt along with a pour point depressant to form an asphalt product. The additional wax can reduce the viscosity of the asphalt product at higher temperatures so that the asphalt product can be mixed and stored at a tower temperature. Additionally, the pour point depressant can unexpectedly improve the low temperature properties of the wax-containing asphalt product.