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Bitumen Production. Various types of crude oil are used for production of bitumen, and all the process occurs at refineries.

The process of oil refining includes fraction distillation, which results in the production of light oil products, such as gasoline, kerosene, ligroin, lubricants etc. After removal of lighter fractions, oil residue remains which is then used to make bitumen.

There are several methods of bitumen production:

1. Concentration of oil residue by vacuum distillation in the presence of water vapor or inert gas – non-oxidized bitumen. Residual bitumen is a low viscosity product and is usually susceptible to oxidation;
2. Blowing of the various oil residue with air oxygen (tower bottoms, tar deasphaltation asphalts, heavy oil, extracts of selective oil purification, cracking residue and mixes) – at high temperature – oxidized bitumen;
3. Mixing of various bitumens – compounded bitumen.

Non-oxidized bitumen is made by vacuum distillation of oil residue and heavy oil. The raw material must have a high concentration of tar and asphalt.

Oxidized bitumen is 75-80% of the total amount of the total amount of bitumen made in the world. Oxidized bitumen is made in batch distillers and in coil type reactors.

Non-oxidized and compounded bitumens have a high content of heavy aromatics and tar, and demonstrate good adhesion, high elasticity, but at the cost of a higher brittle temperature.

Research shows that cracking resistance of asphalt made with non-oxidized and compounded bitumen is significantly higher than that of mixes of similar composition but with oxidized bitumen.

Non-oxidized and compounded bitumens after treatment demonstrate high residual penetration, elasticity and adhesion, that is, the properties of the bitumen remain at the same high level, and the difference between the parameters of oxidized and non-oxidized bitumen increases.

Road Construction Bitumen. Bitumen, as a road construction material, must meet certain requirements to ensure long service life of the structures.

There are three types of road construction bitumen: I, II and III.

The behaviour of type I bitumen is defined by the coagulation structure of asphaltenes, which enlarge in aromatic hydrocarbons and interact through the thin membranes of the dispersion phase.

At higher temperatures, this material does not possess oxidation stability and is prone to aging.

Type I bitumen does not adhere well to minerals which contain less than 30% heavy and alkaline earth metal oxides. Satisfactory results can only be achieved when this parameter is 50% or higher. This bitumen should also not be used with minerals which have porous surface.

The advantages of type I bitumen are:

• good elasticity and plasticity at low temperature;
• wide flexibility temperature range;
• high heat resistance;
• strong adhesion to carbonate and basic materials.

Type II bitumen can be in one of the three rheological states: real viscosity, elastic viscosity and elastic brittleness. The transition to elastic brittleness occurs at -8…-12ºС, the risk of cracks and breaks in roads built with this bitumen is high. The advantages of type II bitumen are high cohesion and deformation stability. Strong and stable adhesion is only possible with mineral materials, containing over 50% heavy and alkaline earth metal oxides. IN other cases, surfactants are required. Type II bitumen is also resistant to oxidation factors at elevated temperatures.

The limitations are:

• lack of elastic and flexible elastic rheological states;
• no elasticity in elastic viscous state;
• llow heat resistance;
• lack of strong adhesion to most materials used in road construction;
• low water resistance.

Type II bitumen properties depend on the presence of asphaltene coagulation structure, and supermolecular thin film resin formation. The binder of this type has all properties necessary for road construction. They do not feature the high parameters of certain rheological and strength indications, characteristic of other types, but they are also free from strong disadvantages, also common for the other types.

Type III bitumen has the following properties:

• flexible-plastic state in a wide temperature range;
• flexible and elastic deformation with low shear loads;
• high strength and deformation stability;
• satisfactory heat resistance;
• satisfactory aging resistance;
• satisfactory adhesion to carbonate and basic minerals.

Water Bitumen Emulsion. Emulsion, in general, is a dispersed system which consists of small droplets of a fluid evenly dispersed in another fluid. In the case of bitumen emulsion, the droplets of bitumen are dispersed in water, which also contains a surfactant emulsifier.

Depending on which fraction is dispersed, emulsion can be direct (oil in water) or reverse (water in oil).

Emulsifier also plays an essential role in the emulsion. In not only forms protective film around the droplets of the dispersed phase, but also reduces interfacial tension, making the emulsification process simpler.

Depending on the charge, there are cationic, anionic and neutral emulsifiers. Neutral emulsifiers have limited use.

In general, both anionic and cationic bitumen emulsions are electrically neutral, since each charged particle of bitumen is enveloped in a layer of ions of the opposing charge.

One of the main factors defining the technical properties of bitumen emulsion is the sign and magnitude of bitumen particle charge. This, as well as surfactant activity, defines the behaviour of bitumen bitumen in contact with various construction materials. For limestone and dolomite, anionic emulsion should be used, while for granite or quartz cationic emulsions are applied. If the selection of the emulsion was correct, its separation occurs relatively quickly, due to the chemical interaction of the mineral and the bitumen particles.

Breaking of the emulsion depends on water evaporation and absorption of moisture by the filler. At low temperature and at high humidity, the breaking process is slower, degrading the quality of road construction. Even if the breaking process of anionic emulsion looks normal, the road top will still be sensitive to moisture.

Cationic emulsion break due to a somewhat different mechanism, not related to water evaporation. This is why they are used with equal success with most currently used road construction materials.

Cationic emulsion are used in the case of high humidity and low temperature (above 5ºС).

Classification of Bitumen. Natural bitumen is a dark brown material, usually solid at room temperature.

Due to its physical and chemical properties, this material is widely used in construction and repairs, such as:

• roofing;
• waterproofing;
• construction of structures;
• road construction.

Beside, bitumen is used successfully in production of rubber, paints and cables.

The raw materials for bitumen production are usually the residual products of crude oil refining, such as heavy oil, tower bottoms, resins, cracking residue, selective oil fraction purification products etc.

There are several classifications of this construction material known today. First of all, bitumen is classified according to its origin: natural, synthetic, pyrobitumen etc.

By production method, bitumen is classified into residual, oxidized and compounded. Residual bitumen is obtained by refining of special types of heavy crude oil. Oxidized bitumen is made by oxidation of heavy fractions left from crude oil refining or their mixtures with extracts, resins and other heavy byproducts of oil refining by air. Compounded bitumen is a mixture of residual and oxidized bitumen.

In terms of application, there are road, roofing, construction, insulation and special purpose bitumen types.

GlobeCore GmbH is one of the world leaders in industrial manufacturing. Products of GlobeCore are used in production of bitumen emulsions, transformer oil regeneration and purification, fuel blending, biodiesel production and emulsification of virtually any materials.

The head office is located in Oldenburg, Germany. Our systems have been supplied to and are successfully operated in 70 countries. A network of 17 dealers supports global sales and services.

GlobeCore established representative offices in United States, and South Africa and in United Arab Emirates to extend reach and improve efficiency. We actively expand production and sales territories, develop our infrastructure and introduce new additional services.

GlobeCore today is a large and diverse company. Over 200 specialists are working as a team from metal cutting to final assembly of the products.

The production facility is equipped in compliance with international industry standards: it features robotic plasma metal cutters, automated welding systems and modern PLC controlled machinery.

Asphalt Emulsion Production. An asphalt emulsion is a dispersed system which consists mainly of water and asphalt. One substances is dispersed as droplets in the other.

Asphalt is pulverized using special devices, such as colloid mills, also referred to as dispersers or homogenizers.

In the general case, the asphalt emulsion production process using a colloid mill is as follows. At the first stage, asphalt is pulverized. The forces in the flow turn the spherical droplets into cylinders. If the ratio of the length and diameter reaches a certain value, the droplet divides into two parts: small and large. The process continues until the sizes of the large and small droplets are the same, which usually occurs at the size of 0.01 micron.

The reverse process is also possible, that is, coalescence of asphalt droplets, which is rather undesirable. To prevent this, another component is used: a surfactant emulsifier, which concentrates on the boundary between water and asphalt. The emulsifier attaches itself to the droplets of bitumen creating a protective layer separating the droplets.

Since the layer must be strong enough, the acidity of the water phase must be kept within certain limits. This is achieved by adding chlorine acid.

Most road construction operations use cationic asphalt emulsions, due to good interaction with stone. To make cationic emulsion, several operations are performed:

• supplying asphalt from storage, heating and, if necessary, dehydration;
• preparation of water solution of emulsifier;
• production of emulsion by mixing the asphalt and the emulsifier water solution;
• storage and shipment of the product;
• heating and maintaining the temperature of asphalt and the emulsifier solution.

GlobeCore offers the UVB-1 units, simple in service and operation, which can produce high quality asphalt emulsions, which fully meet the ASTM D 2397-98 and D977-98 standards; the production capacity is 1 to 32 m3/hour.

The equipment can produce consistently high quality emulsions regardless of the initial asphalt quality. All types of emulsion can be produced: CRS, CMS and CSS-1,2, as well as anionic emulsions, including subtype h.