Natural bitumen

Roofs are a basic element of shelter from inclement weather. Natural or hewn caves, including those of snow or ice, ate early evidence of human endeavors for protection from the cold, wind, rain, and sun. Nomadic people, before the benefits of agriculture had been discovered and housing schemes developed, depended on the availabiUty of natural materials to constmct shelters. Portable shelters, eg, tents, probably appeared early in history. Later, more permanent stmctures were developed from stone and brick. SaUent features depended strongly on the avadabihty of natural materials. The Babylonians used mud to form bricks and tiles that could be bonded with mortars or natural bitumen. Ancient buildings in Egypt were characterized by massive walls of stone and closely spaced columns that carried stone lintels to support a flat roof, often made of stone slabs. 

Orimulsion is a relatively new fuel that is available for the gasification process. Orimulsion is an emulsified fuel, a mixture of natural bitumen (referred to as Orinoco-oil), water (about 30%), and a small quantity of surface active agents. Abundant Orinoco-oil resei ves he under the ground in the northern part of Venezuela. 

Properties and extraction processes Oil-sand or tar-sand deposits are naturally occurring mixtures of quartz sand, silt and clay, water and natural bitumen (also called crude or natural bitumen), along with minor amounts of other minerals. Each particle of oil sand is coated with a layer of water, which is surrounded by a thin film of bitumen. 

Sulfur content in crude oils and natural bitumens varies from less than 0.05 to more than 14 weight percent, but few commercially produced crude oils exceed 4% sulfur. Tissot and Welte (25) show a frequency distribution of crude oils based on over 9,000 samples and report the average sulfur content as 0.65%. The distribution is clearly bimodal with a minimum at about 1% sulfur. Oils with less than 1% sulfur are classified as low-sulfur, and those above 1% as high-sulfur. In general, high-sulfur oils are derived from carbonate or carbonate-evaporite rock sequences whereas low-sulfur oils are derived largely from clay-rich clastic sequences f25-26.28-29). 

Roadifer, R. E. In Exploration for Heavy Crude Oil and Natural Bitumens Meyer, R. F., Ed. AAPG Studies in Geology 25 American Association of Petroleum Geologists Tulsa 1987 3-23. 

Figure 5.12. Proven reserves of oil shale and natural bitumen (unit Wy/m i.e., for each country, the average number of years for which an energy flow of 1 W per m of land surface could be derived at 100% energy extraction efficiency) (based upon data from World Energy Council, 1995 with area-based layout from Sorensen, 1999).

Figure 10. Composition of shale oil, natural bitumen present at depth, and pooled oil, which are all derived from lower Jurassic shales, Paris Basin.

There are two major causes for the differences observed between shale oil and crude oil. One is due to generation by pyrolysis of compounds unusual in natural bitumens and crude oils, such as unsaturated hydrocarbons (olefins) Figure 10. Nitrogen hetero-compounds are also much more abundant than they are in natural bitumen or crude oils. The other difference is due to the migrated character of pooled oil which results in a preferential migration of hydrocarbons, especially saturates, and a retention of most of the N,S,0 - compounds in the source rock (1 ). Thus natural bitumen has an intermediate composition, separated from shale oil by the conditions of pyrolysis and from pooled oil by migration across sedimentary beds. 

Here we present some results concerning the role that ion irradiation has in 1. modifying cluster assembled carbon thin films obtained by low energy cluster beam deposition (LECBD) and containing a cabynoid component and 2. producing carbynoid-like materials after irradiation of solid frozen benzene and of asphaltite, a natural bitumen. 

In this paragraph we report some results obtained after ion irradiation of asphaltite, a natural bitumen, and benzene frozen at low T (16 K). 

Gilsonite was discovered in 1882 by S. H. Gilson of Salt Lake City, who also later commercialized it. It is a natural bitumen found in Utah near the Colorado border. It is a material of good uniformity, occurring in veins from a fraction of an inch to 18 ft. thick. The veins are generally more or less vertical... 

The porphyrin metallo complexes in crude oils, asphaltenes and other natural bitumens are chiefly those of vanadium and nickel although copper, iron and even uranium have been suggested. Recently in a Precambrian shale, porphins were found to chelate with iron, zinc and copper in addition to vanadium and nickel.The origin of these complexes is still uncertain, although several theories have been advanced. Some of these theories could be verified or possibly even disproved if the porphyrin type bound to each metal was known. Furthermore, since these heavy metals are harmful to both health and catalysts, a systematic study of demetallation of metalloporphyrins should prove useful. 

Tannenbaum E., Starinsky A. and Aizenshtat Z. (1987) Light oils transformation to heavy oils and asphalts. In Exploration for Heavy Crude Oils and Natural Bitumen (ed. R. F. Meyer), pp. 221-231. Studies in Geology American Association of Petroleum Geologists, Series 25, Tulsa. 

Bituminous materials are dark brown or black, semi-solid or liquid, thermoplastic mixtures of hydrocarbons derived from natural or synthetic processes in which hydrocarbon mixtures have lost their volatile components leaving a denser residue. Natural bitumens come from exposed and weathered petroleum and rock deposits. Synthetic bitumens come from the residue remaining after the distillation of petroleum, coal tar, and other organic materials like wood and peat. The complexity of the high molecular weight hydrocarbon oils and resins bitumens contain make complete chemical characterization impossible. The terms bitumen, tar (8007-45-2), pitch (61789-60-4), and asphalt (8052-42-4) apply to any of these substances, although pitch and tar also describe the sticky resins that exude from various trees. 

Nadirov, N.K., Zaikina, R.F., and Zaikin, Y.A. 1994. Progress in high viscosity oil and natural bitumen refining by ionizing irradiation, in Oil and Bitumen. Republic of Tatarstan, Russia Kazan, Vol. 4, pp. 1638-1642. 

Bitumen is a naturally occurring hydrocarbon that exists in a semi-solid or solid phase in natural deposits. The most important reservoirs of bitumen are found in Canada and Venezuela. Among the problems encountered when recovering bitumen, its high viscosity is one of the greatest. Natural bitumen has a viscosity greater than 10000 mPa, measured on a gas-free basis at its original temperature in the deposit and atmospheric pressure (38, 39). 

As time passed, bitumen technology had to develop to adjust to new demands of the updated transport networks. Hence, bitumen used for road paving has been modified via the addition of polymers, in order to improve the mechanical characteristics of natural bitumen. However, there are some special uses in which traditional bitumen is replaced by design materials called synthetic binders (Figure 10.1). 

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