Bitumen Oxidation

MODELING OF BITUMEN OXIDATION AND CRACKING KINETICS USING DATA FROM ALBERTA OIL SANDS... 

Table 18.1 Bitumen Oxidation and Cracking Formulation of Two-Component Models...

Modeling of Bitumen Oxidation and Cracking Kinetics Using Data from Alberta Oil Sands... 

Depending on the application, relatively hard distillation bitumen, oxidation bitumen, or high-vacuum bitumen (hard bitumen) are used for physically drying bitumen paints. Waterborne bitumen paints and thick coatings (bitumen emulsions) are produced from moderately hard distillation bitumen. 

Al Douri, A. H., Kopsch, H., Neumann, H.-J. Bitumen-Oxidation in Gegenwart von Radi-kalbildnem. Erdol und Kohle, Erdgas, Petrochemie 42 (1989) p. 68-71. 

Chemical hardening of the bitumen with time in service is also known as ageing of the bitumen. It occurs because of the oxidation of organic compounds and because of further volatilisation of volatile ingredients of the bitumen. This stage is also called bitumen oxidation. 

Finally, it should be mentioned that bitumen oxidation is more intense at the surface (surface layer) than within the bituminous mixture (layers beneath). 

The reduction of permeability attributed to proper compaction has the benefit of not only permitting smaller water quantity to pass through the layer to the underlying layers, bearing the well-known negative results, but also allowing less air to move through the asphalt. As a consequence, the rate of bitumen oxidation decreases. 

Bitumen oxidation Increasing plasticity of bitumen atmos. 280-300 - O2 cont. process also used for pitch blowing... 

Waterproofing, whether it has to do with protecting civil engineering structures or roofs or terraces. Poured asphalt, often placed in layers with kraft paper, oxidized bitumen or modified bitumen can be used, generally with copolymer. The modified bitumen are used for the making prefabricated multi-layer waterproofing composites. 

Electrical insulation with oxidized bitumen electrical cabling, condensers, batteries. 

Bitumen paints and varnishes, which are mixtures of hard bitumen, usually oxidized, and a light or very light solvent. 

A bitumen sample is oxidized at high temperature under well defined conditions and its physical characteristics are measured before and after this artificiai ageing process. The method is defined in France as AFNOR T 66-032 and in the USA by ASTM D 2872 (Rolling Thin-Film Oven Test). 

Bitumen Ionomers. Moisture-resistant asphalts (qv) have been prepared by reaction of metal oxides with acid-functionalized bitumens (75). Maleic anhydride or sulfur trioxide/trimethylamine complexes have been used successfully for introduction of acid groups into asphaltic bitumens. 

In the other market areas, lead naphthenates are used on a limited basis in extreme pressure additives for lubricating oils and greases. Sodium and potassium naphthenates are used in emulsiftable oils, where they have the advantage over fatty acid soaps of having improved disinfectant properties. Catalyst uses include cobalt naphthenate as a cross-linking catalyst in adhesives (52) and manganese naphthenate as an oxidation catalyst (35). Metal naphthenates are also being used in the hydroconversion of heavy petroleum fractions (53,54) and bitumens (55). 

Carbon tetrachloride [56-23-5] (tetrachloromethane), CCl, at ordinary temperature and pressure is a heavy, colorless Hquid with a characteristic nonirritant odor it is nonflammable. Carbon tetrachloride contains 92 wt % chlorine. When in contact with a flame or very hot surface, the vapor decomposes to give toxic products, such as phosgene. It is the most toxic of the chloromethanes and the most unstable upon thermal oxidation. The commercial product frequendy contains added stabilizers. Carbon tetrachloride is miscible with many common organic Hquids and is a powerhil solvent for asphalt, benzyl resin (polymerized benzyl chloride), bitumens, chlorinated mbber, ethylceUulose, fats, gums, rosin, and waxes. 

Erd-ozyd, n. oxide of an earth metal, -pech, n, mineral pitch, asphalt, bitumen, erdpech-artig, a. asphaltic, -haltig, a. containing asphalt, asphaltic. 

Oxy-aldehyd, n, hydroxy aldehyde, -ammo-niak, n, oxyammonia (hydroxylamine), -azoverbindung, /. hydroxyazo compound, -benzol, n, hydroxybenzene (phenol), -bem-steinsaure. /, hydroxysuccinic acid (malic acid). -biazol, n. oxadiazole, oxdiazole. -bitumen, n, oxidized bitumen, -carbon-s ure, /, hydroxycarboxylic acid, -chlnoltn, n. hydroxyquinoline, -clunon, n. hydroxy-quinone. -chlorid, n. oxychloride, -chlor-kupfer, n. copper oxychloride, -cyan, n. oxycyanogen. 

These are semisolid or solid substances formed in nature from crude oils after the volatile components have evaporated and the remainder has undergone oxidation and polymerization. They are also referred to as bitumens, waxes, and pitch. These materials are believed to consist of mixtures of complex organic molecules of high molecular weight. As with crude oils, which contain thousands of different chemical compounds, an exact chemical analysis for identification and composition is impractical to perform on the solid deposits of petroleum. 

An interesting application of sprayed aluminium is for resistance to high-temperature oxidation up to 900°C. The article is grit-blasted and aluminium sprayed, usually to a thickness of 0-008 in (0-2 mm). It is then treated with a sealing composition which may be bitumen or water-glass, and is diffusion annealed in a furnace at 850 C for approximately 30 min. The final coating... 

Atmospheres polluted by oxidising agents, e.g. ozone, chlorine, peroxide, etc. whose great destructive power is in direct proportion to the temperature, are also encountered. Sulphuric acid, formed by sulphur dioxide pollution, will accelerate the breakdown of paint, particularly oil-based films. Paint media resistant both to acids, depending on concentration and temperature, and oxidation include those containing bitumen, acrylic resins, chlorinated or cyclised rubber, epoxy and polyurethane/coal tar combinations, phenolic resins and p.v.c. 

Boron oxide Bioaerosol Bitumen fume Bromotrifluoro methane Bromoxynil Bromoxynil octanoate Butadiene (1,3-butadiene)... 

In the laboratory of Professor R.G. Moore at the University of Calgary, kinetic data were obtained using bitumen samples of the North Bodo and Athabasca oil sands of northern Alberta. Low temperature oxidation data were taken at 50, 75, 100, 125 and 150"C whereas the high temperature thermal cracking data at 360, 397 and 420"C. 

Figures 18.13, through 18.17 show the experimental data and the calculations based on model I for the low temperature oxidation at 50, 75, 100, 125 and 150TZ of a North Bodo oil sands bitumen with a 5% oxygen gas. As seen, there is generally good agreement between the experimental data and the results obtained by the simple three pseudo-component model at all temperatures except the run at 125 TT. The only drawback of the model is that it cannot calculate the HO/LO split. The estimated parameter values for model I and N are shown in Table 18.2. The observed large standard deviations in the parameter estimates is rather typical for Arrhenius type expressions.

Figure 18.13 Experimental and calculated concentrations of Coke (COK) "A , Asphaltene (ASP) o" and Heavy Oil + Light Oil (HO+LO) "a" at 50 °C for the low temperature oxidation of North Bodo oil sands bitumen using model l.

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