home Sample Documents Production of bituminous materials. Bitumen production

Production of bituminous materials. Bitumen production

Bitumen production is complex technological process where different grades of oil are used. And all technological operations are carried out on the territory of oil refineries.

Bitumen production technology

The oil refining process includes fractional distillation, as a result of which light oil products such as gasoline, kerosene and naphtha, lubricating oils, etc. are obtained. After the selection of fractions lighter in mass (tar, cracking), oil residues are formed, which are subsequently used to obtain oil bitumen with the given properties.

AT modern conditions bitumen can be produced in one of the following ways:

concentration of oil residues by distillation under vacuum. In this case, an inert gas or water vapor is used. For the production of residual bitumen from asphalt-resin oils, atmospheric distillation is used;
oxidation of various oil residues air oxygen at a temperature of 180-300ºС. Such residues can be semi-tars, tars, fuel oils, deasphalting asphalts, cracked residues, or mixtures thereof;
tar deasphalting selective solvents;
mixing (compounding) oil residues with distillates, as well as with oxidized or residual bitumen.

In practice, various combinations of the methods listed above have also found application.

Unoxidized bitumen is produced by vacuum distillation of oil residues and heavy oils. The feedstock must have a high concentration of tar-asphaltene substances.

Oxidized bitumens make up 75-80% of the total amount of this building material produced in the world. The production of oxidized bitumen is carried out in batch cubes and coil-type reactors.

Unoxidized and compounded bitumens have a high content of heavy aromatics, resins and are characterized by good adhesion characteristics, high extensibility, but a higher brittleness temperature.

Studies show that the crack resistance of asphalt concrete pavements created using non-oxidized and compounded bitumen is significantly higher than that of compositions of the same composition, but containing oxidized bitumen.

Non-oxidized and compounded bitumen after heat treatment are characterized by high values of residual penetration, extensibility and adhesion, that is, the performance properties of bitumen remain at a high level, and the difference in the ratio of indicators between oxidized and non-oxidized bitumen increases even more.

Raw material for bitumen production

Most often, the main raw material for the production of bitumen is tar or deasphalting asphalts (resinous asphaltene substances). In some literary sources, they are found under the name "precipitated bitumen". Note that sometimes extracts of selective oil refining, thermal cracking residues or pyrolysis resins can be used to produce bitumen.

In order to obtain highly plastic bitumen, characterized by high thermal stability and good binding properties, it is necessary to use raw materials of a certain and constant quality.

Tars of heavy oils, which contain many resinous-asphaltene substances, usually have the necessary properties. In the general case, the following statement is true: the greater the asphaltene:resin ratio, the better the properties and structure of the produced bitumen. In grades of heavy oils, this ratio is 1.0-1.3.

In countries with small reserves of such oils, it is necessary to use mass-produced raw materials, which leads to a discrepancy between the properties of the resulting product and the established quality standards.

Production of residual bitumen

The production of residual bitumen is the simplest and most economical technology. To determine the suitability of a particular grade of oil for use in obtaining residual bitumen, it is necessary to evaluate the yield of a binder from it with a needle penetration depth at 25ºС 100 per 0.1 mm.

The production of residual bitumen can be considered economically justified in the case when the yield of the finished product is at least 10-20%. To obtain such bitumen, vacuum distillation raw materials are used, consisting of organic and heterogeneous compounds, most often fuel oil.

The qualitative characteristics of residual bitumen can be controlled by changing the modes of the vacuum column. To a greater extent, the efficiency of the process is influenced by the depth of vacuum in the vacuum column feed zone, as well as the presence of contact devices with low hydraulic resistance, which provide a pressure drop over the column height of not more than 15-20 mm Hg. At the same time, a pressure of no more than 20 mm Hg is maintained at the top of the vacuum column.

The production of residual bitumen is characterized by a significant decrease in the content of paraffin-naphthenic hydrocarbons, which is due to their higher volatility compared to other substances of the same group. Superheated steam is needed to reduce the content of paraffin-naphthenic hydrocarbons in bitumen and to reduce the distillation temperature of the residues. This makes it possible to obtain residual bitumen with a high softening point.

But this approach has certain disadvantages, which are expressed in the presence of additional costs and corrosion of the materials from which the equipment is made. This led to the emergence alternative way, consisting in the so-called "dry" vacuum distillation of fuel oil, which requires highly efficient systems to create a vacuum. In general, vacuum technologies have good prospects for the production of residual bitumen, as they allow for deeper oil refining.

Highly resinous heavy sour oil with a high content of asphalt-resinous substances can serve as a raw material for obtaining residual bitumen.

During vacuum distillation, it is very important at the initial stage to extract distillate fractions from oil in order to obtain motor fuel. by-product this process- tar, can be further used as a feedstock in the production of bitumen.

With the help of processes for obtaining residual bitumen, it is very difficult to ensure the release of refractory bitumen, which is a significant drawback.

World production of bitumen

Demand for bitumen and bituminous materials is driven by funding for road construction. It is also affected by confluence of factors such as the economics of alternative road surfaces, the possibility of using new types of road surfaces, the price of oil and the possibility of transporting material. The supply is mainly influenced by the volume of refined oil.

To date, the world bitumen market is estimated at 100 million tons per year, of which one third falls on the countries of the Asia-Pacific region, one third - on North America. Europe produces 18% of the world's bitumen. Stable demand for road surfaces arranged using bitumen is observed in the Middle East and Africa. in Western Europe and North America there is a tendency to reduce the demand for this building material. The peak of bitumen consumption in China was recorded in 2012 and so far there are no prerequisites for an increase in volumes.

In total, about 20 million tons of bitumen are produced annually in the European Union. The largest consumption was recorded in Germany and France (2 million tons), as well as the UK (1.3 million tons). Demand for bituminous materials is declining in countries such as the Netherlands, Belgium and Ireland. Poland and Germany, on the contrary, consume more bitumen.

The largest exporters among the North African and Middle Eastern countries are Algeria and Turkey. And even Tunisia exports bitumen, albeit in small volumes.

In summer, there is an increased demand for bitumen, which explains the rise in prices to $50-70 per ton. At the same time, in Africa, they ask for $80 per ton for a similar product.

Modified Bitumen Plants from GlobeCore

Equipment performance from the company GlobeCore , for production modified bitumen, from 4 m3 to 22 m3 per hour:

Installation of bitumen modification with polymers - (PBV) USB-2M, 4-7m3/hour

It's hard to imagine modern construction, both roads and buildings without the use of bitumen. Its widest application in these areas is determined by the unique properties of the material:

heating leads to the fact that it becomes more viscous, almost any Construction Materials wetted by it;
when cooled, it thickens, gradually turning into a monolithic solid structure along with the fillers included in it;
hydrophobic, which is transferred to fillers and contact media after impregnation, this predetermines the use of bitumen for waterproofing.

The raw materials for the production of bitumen include materials containing substances with high viscosity, asphaltene components. They are obtained from the waste generated during oil refining. The fossil natural component of the resins is extracted by the method of physical impact on the bitumen-containing rock. Most often, this is the treatment of the rock with high-temperature water vapor. At the same time, the viscosity of the components decreases, and in this way they are washed out of the rock.

The described technology is classical, but at present, instead of natural production, the most common technology is the production of petroleum bitumen. industrial enterprises from waste generated during crude oil refining.

Naphthenic and naphthenic-aromatic oils during vacuum distillation give the product tar, which is the basis for the production of bitumen. If special additives are introduced into its composition, then a substance with high performance characteristics is obtained, which is used as bitumen. The processing of paraffinic oil produces a lot of useful waste, and the resulting tar is mixed with special components and sent to the reactor for oxidation.

During the vacuum distillation of fuel oil and the subsequent deasphalting of the oil components of oil, by-products of the tar composition are obtained. Our country has huge reserves of oil with a high content of bitumen, but the leading place in the production of bitumen is occupied by the oxidation method.

Taking into account the fact that Russia still lags behind the leading world powers in terms of the length of high-quality roads, opening a bitumen production plant in Russia is a very profitable and currently in demand enterprise.

Composition of bitumen

The composition determines the further use of bitumen. It consists of 14% hydrogen and 70% carbon, the rest is impurities of oxygen, sulfur and other chemical elements. To put it simply, it is carbon with various additives. Its properties are affected not so much by its elemental composition as by the types of hydrogen-carbon compounds determined by the bitumen production technology.

Let's name the types of these compounds:

an oil component that provides the material with fluidity;
resinous inclusions that give the product elasticity;
asphaltene compounds, due to which bitumen has viscosity.

The content of oils in bitumen in relation to its total mass reaches 60%, which is the predominant share. The higher this share ratio, the greater the material's penetrating ability in relation to other media. It contains much less resins, usually their amount does not exceed 30%. Resins are ductile, and their density is much higher than that of oils. Resins are solid, viscous and semi-liquid, their viscosity is determined by temperature. The higher it is, the lower the viscosity of the resins and the bitumen itself. With sufficient heating in a bitumen plant, a user-friendly liquid bitumen can be obtained.

Production equipment

Given what is used as a feedstock, various industrial equipment for the production of bitumen. These are various boilers and furnaces, other devices. To make it convenient to transport the material from the manufacturer to the place of use, it is initially stored mainly in solid form. The storage of bitumen does not pose any particular problems at average ambient temperatures. Only in hot weather does it soften greatly and this significantly complicates loading and transportation operations. Most often, bitumen is stored in briquettes. But in order to use it in road and industrial construction, it is necessary to heat solid pieces to the temperature at which they will take the required viscosity. Usually they are heated to a liquid state and only then used in various technological operations.

Installations for melting at enterprises of road and construction specifics not only bring the raw material into a liquid state, but also maintain it in such a readiness for use for an arbitrarily long time. These units are manufactured in mobile and stationary versions. The mobile installation is moved by car, while the stationary one always remains in one place. But the productivity is higher precisely for a stationary installation, since it has larger bitumen tanks and more powerful heating furnaces.

According to the method of heating, all furnaces for the production of bitumen are distinguished into direct heating devices, indirect heaters with coolant circulation and their combined versions. It is also necessary to distinguish installations for heating road and construction bitumen according to the defining features of its production. There are such installations in which the pipes with the heat carrier are located throughout the volume of the tank, while in other installations the heating pipes are located only in the receiving chamber. Those installations in which the heaters are located around the perimeter are better. After all, in them the raw material melts evenly throughout the volume and at the same time the entire contents of the container come into operational readiness.

Also, bitumen heating plants are divided according to the method of loading solid raw materials into them - these are devices with loading from above and from the side. Lateral loading is better because raw materials can be fed into the plant both manually and with the help of a special conveyor or loader.

Types of bitumen for construction

In the construction industry, this material is used for the preparation of various mastics, for waterproofing foundation work and for roofing. Basically, these are substances obtained during the refining of oil. Also, construction bitumen has found the widest application in the construction of roads.

According to the indicated areas of application, a simple classification of this building material can be made:

for use in the construction of buildings and structures;
for the production of roofing works;
for road construction.

The domestic industry produces liquid, semi-solid and solid bitumen for the construction segment of the industry. Liquid is also divided into several classes according to the thickening rate.

Construction bitumen grades from BN 50/50 to BN 90/10 are used for waterproofing works. This raw material is still widely used in the manufacture roofing materials, such as hydroisol, luberite, isoplast, etc. In each of the listed materials, special additives are introduced into the raw material to increase strength, frost resistance and other important operational parameters polymer composition. All polymeric bitumen, used in construction, are combustible, their spontaneous ignition temperature is 368 ° C. With the available source of open fire, they light up already at 230 ° C.

In order to waterproof the foundations of buildings and structures, special insulating bitumen is used. It is able to slowly harden and at the same time retain its properties for a long time, tightly binding to the surface of reinforced concrete products.

Road bitumen is used to impregnate the top road layer and to pre-treat the ground before asphalt is laid. In this specificity, both liquid and viscous formulations are used. They are also combustible, the flash point of the material at an external open source is in the range from 60 to 120 °C.

Bitumen for road construction

In the construction of roads, a polymeric bitumen product is used, now in Russia the production of road bitumen is increasing, but still, in terms of the volume of material produced, it lags far behind world indicators.

Such installations are characterized by high energy consumption, their electrical power reaches 200 kW or more. Due to the high cost of electricity, many asphalt concrete plants cannot organize the modification of bitumen with binder polymer compositions.

Bitumen can be safely attributed to products with seasonal demand, this is primarily determined by seasonality. road works in our country. The price of bitumen per ton rises sharply in summer and falls in winter. Due to the fact that this material is produced from oil, the instability of oil quotations on the world market also has a significant impact on the cost of bitumen.

Also, the price of bitumen strongly depends on the remoteness of the consumer from the production complexes, this is associated with considerable costs for transporting the material both in liquid state in containers and in solid form when solid bitumen is transported in bags.

Bitumen trade

Currently, bitumen trade in Russia is steadily increasing. Selling companies organize mainly the sale of bitumen in bulk, but do not refuse from retail this material of wide and steady demand.

Consider the prices for bituminous raw materials, which have settled on domestic market currently:

Analyzing the above table, we can conclude that the cost of bitumen is currently quite high. All available old stocks and bitumen waste generated during production and transportation are used. This allows producers oil companies receive an estimated profit, but hinders the development of road construction in the country.

Bitumen production plant - equipment that allows you to get bitumen and bitumen emulsions from fuel oil and tar by pre-treatment and subsequent oxidation. In this case, the most suitable raw materials are highly resinous low-paraffin oil products. Conversely, highly paraffinic oils are not recommended as raw materials. The fact is that as a result of oxidation, asphaltenes and carbenes are formed in such oil products, which reduce the strength and elasticity of bitumen.

A standard bitumen production plant consists of oxidizing reactors, a furnace, bitumen pumps, a gearbox, an electric motor and a control panel. With the help of pin couplings, the transmission is carried out between the pump and the gearbox and, accordingly, between the gearbox and the electric motor. Also, the bitumen production plant is equipped with rotating parts covered with protective covers.

If the bitumen production plant is used in industries with increased explosion hazard, the equipment must be equipped with pumps with mechanical seals. In addition, only bitumen plants with explosion-proof motors may be used under these conditions.

It is worth noting that in modern models of equipment, the release of hot bitumen vapors into the surrounding atmosphere is excluded, which means that the bitumen production unit does not violate the environmental safety of the city.

What products can be obtained with a bitumen production plant?

road bitumens, which are widely used in road construction. Born in a bitumen plant, this product is best suited for the preparation asphalt mixes.
roofing bitumen, indispensable in the manufacture of various roofing coatings.
insulating bitumens, which are used to protect pipelines from corrosion.
The bitumen production plant also makes it possible to produce construction bitumen in large quantities, which perform many useful functions. In particular, building bitumens provide excellent foundation waterproofing.
Finally, a bitumen plant is required for the production of bituminous mastics.

How is the finished product obtained in a bitumen plant?

There are three methods for the production of road, roofing, insulating and other types of bitumen: vacuum distillation, oxidation of petroleum products during high temperature and compounding bitumen.

As a result of deep vacuum distillation, residual bitumen is obtained.

Oxidation of oil products with air, taking place at high temperatures, allows the production of oxidized bitumen.

The latter method involves compounding both residual and oxidized bitumen.

What are the advantages of a bitumen plant?

Provided that for the manufacture final product suitable raw materials are used, a bitumen production unit - whether it is equipment of foreign or domestic production, allows you to obtain and sell bitumen of exceptional quality without serious time and energy costs. Today we work both on the territory of Russia and in the CIS countries.

Bitumen plant is optimal solution if you need a mobile mini-factory. If the plant is available, it is possible to manufacture bitumen and bituminous mastics directly in washing and steaming stations, fuel oil storage facilities and in other places where oily residues are stored or disposed of.

What products can be obtained with a bitumen production plant?

road bitumens, which are widely used in road construction. Born in a bitumen plant, this product is best suited for the preparation of asphalt mixes.
roofing bitumen, indispensable in the manufacture of various roofing coatings.
insulating bitumens, which are used to protect pipelines from corrosion.
The bitumen production plant also makes it possible to produce construction bitumen in large quantities, which perform many useful functions. In particular, building bitumens provide excellent foundation waterproofing.
Finally, a bitumen plant is required for the production of bituminous mastics.

How is the finished product obtained in a bitumen plant?

There are three methods for the production of road, roofing, insulating and other types of bitumen: vacuum distillation, high temperature oxidation of petroleum products, and bitumen compounding.

As a result of deep vacuum distillation, residual bitumen is obtained.

Oxidation of oil products with air, taking place at high temperatures, allows the production of oxidized bitumen.

The latter method involves compounding both residual and oxidized bitumen.

What are the advantages of a bitumen plant?

Provided that suitable raw materials are used for the manufacture of the final product, the bitumen production plant - whether it is foreign or domestic equipment, allows you to obtain and sell bitumen of exceptional quality without serious time and energy costs. Today we work both on the territory of Russia and in the CIS countries.

The bitumen plant is the optimal solution if you need a mobile mini-plant. If the plant is available, it is possible to manufacture bitumen and bituminous mastics directly in washing and steaming stations, fuel oil storage facilities and in other places where oily residues are stored or disposed of.

Bitumens on diesel fuel or liquefied gas

Highly efficient, no smoker
on diesel fuel (version 1) or liquefied gas(version 2)
for heating viscous materials.

database

Bitumen is designed to heat viscous materials (bitumen, resins, etc.) and fill loading cracks.

It is used in the construction of buildings, roads, roof repairs, etc.

specifications:

DB-1.5	DB-1.0	DB-0.5	db's
Amount of heated bitumen, m2	1,0	0.7	0,4	with technically requirements clients
Heating time, time	3	2.5	2
Diesel fuel consumption, l / h	3.0	2.5	2,0
Thermal power of the burner, kW	35	35	30
Fuel tank capacity, l	35	35	35
Overall dimensions, mm (width / height / length) (without trailer)	1200/1500/2220	1200/1500/2220	1050/1350/1650
Overall dimensions, mm (width / height / length) (with trailer)	2100/2200/3655	2100/2200/3655	2100/2050/3655
Weight (without trailer), kg	350	300	150
Weight (with trailer), kg	950	900	750
Bitumen price (without trailers), thousand rubles	108	103	90
The price of the trailer PTTS-1.7, thousand rubles	85	85	85

The main advantages of bitumen welding:

Completion of combustion - no smoke.
It is simple and reliable in operation.
The presence of thermal insulation of the body.
Autonomy.

Bitumen production: technologies, raw materials and equipment

Electric bitumen cooker with agitator

An electric bitumen cooker with a stirrer and a heat-insulated body is designed for soft heating and maintaining the temperature of bitumen, preparing mastics and liquid and amorphous media similar to them in terms of physical and chemical properties, as well as for mixing them during repair, construction and waterproofing works at a temperature environment from minus 20°С to plus 45°С.

BEMT	BEMC

Technical haCharacteristics:

	BEMT-0.25	BEMT-1.0	BEMC
AC supply voltage, V	380
Total power of heaters, kW	10	30	10-30
Loading capacity, l	250	1000	250-1000
Heating temperature range, ° С	40 to 250
Agitator drive	geared motor	electric motor
The number of revolutions at the output, rpm	18	33	750, 1000, 0-1000
Drain pipe diameter, mm Du	50-100
Overall dimensions, mm LxWxH (without trailer)	1800	2000
700	1100
1250	1350
Weight (without trailer), kg, no more	150	500
Protection class against electric shock	1

Technical description:

The bitumen cooker consists of a horizontally located cylindrical tank with a loading hatch, equipped with electric heating elements, a mixing device with a motor-reducer or an electric motor, a drain device and a control unit.
The control unit allows you to set the temperature on the heating elements, inside the tank, block their installation, as well as turn on and off the electric motor of the agitator.

The mixing device for bitumen cookers is made in the form:

Horizontally positioned paddle agitator with geared motor;

2. Vertically positioned centrifugal agitator with fixed or variable speed motor.

Oil road bitumen, viscous

Oil road bitumens are divided into viscous and liquid. Viscous bitumens differ: BND (oil road bitumen) and BN (oil bitumen). Viscous oil road bitumens are produced in five grades: BND 40/60, ...

Methods for the industrial production of petroleum bitumen

Liquid petroleum road bitumen

Liquid petroleum road bitumen, having a fluid state at positive temperatures, is used as a binder in asphalt concrete mixtures used both in cold (with a temperature of ...

Roofing bitumen

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Construction bitumen

Petroleum construction bitumen is obtained by oxidation of residual products of direct distillation of petroleum and their mixtures with asphalts and extracts. oil production. Sometimes construction bitumen is obtained by compounding (mixing) oxidized and non-oxidized ...

Insulating bitumen

Oil insulating bitumen grades: BNI-IV-Z, BNI-IV and BNI-V are used to isolate pipelines from soil corrosion. Insulating bitumens are obtained by oxidation of the residual products of direct distillation of oil ...

Special oil bitumen

Special oil bitumen grades B, V, G are obtained by oxidation of heavy residues of atmospheric-vacuum distillation of highly resinous oils and are used mainly in the paint and varnish industry.

They have …

The use of petroleum bitumen in road construction

The choice of bitumen is determined by the area of application, the accepted technology for the production of works and the technical and economic requirements for the structure being constructed. Technological conditions for the use of bitumen at the stage of preparation of asphalt concrete mixtures largely depend on the brand ...

Article from the category: Homemade

Bitumen cooker from an old tank

The author of the letter shared with readers the experience of making a barbecue from the tank of an old washing machine.

Today he shares with us another interesting idea, irreplaceable during construction or repair - bitumen cooker.

Bitumen is a necessary thing in the economy: both as a waterproofing agent and as an adhesive material (besides, it is relatively cheap). But to bring it into working condition, i.e. melting is a laborious task, requiring a considerable investment of time and fuel. The essence of my device is simple. Due to a temporary lack of gas, I had to install an electric heater with a capacity of 50 liters at home.

After a couple of years, it leaked, and, as you know, these units cannot be repaired with such “joy”. For a long time he was lying in the garage, I still could not find a use for him. And then an idea came, and I realized it - I made an excellent bitumen cooker.

Well, now in more detail how to make a bitumen cooker with your own hands, with a picture, with a photo, in stages.

With a grinder we make a transverse cut of the cover and the bottom of the casing, then a longitudinal cut of the remaining part and free the inner tank.

We remove the thermal insulation (this is done easily) and proceed to its modernization. We remove the coupling and the check valve from the two pipes (2) and shorten them with a grinder to 3-5 cm: they serve to communicate the internal cavity with the atmosphere. Handle (1) - welded curved piece of metal pipe or rod. Side axles (4) in the amount of 2 pcs.

- pieces of a water pipe with a diameter of 25 cm, a length of 3-5 cm. They are welded oppositely, just above the center of the tank and serve as its support on legs.

At their ends we drill holes for fixing the legs. Patch (5) - welded piece of metal plate to prevent burning of the bottom of the tank - the thicker it is, the longer the service life of the product. The legs (6) have a cruciform base made of metal pipe scraps (strips, angles, rods, etc.) and a stand (height and diameter optional) made of a metal pipe.

How is bitumen produced?

At its upper end, we weld a ring with a diameter of 32 mm (we saw off from the water pipe).

The drain pipe (3) must have a 32 mm thread at the end. It is screwed in instead of the heating element. You can make it yourself by welding at an angle to a piece of pipe with a diameter of 32 mm or 40 mm thread (sold in plumbing).

The legs on the tank sleeves can be fixed with a regular nail or a suitable piece of wire. This collapsible design increases the mobility of the product during movement and transportation.

The drain pipe (3) is unscrewed, through this hole the tank is filled with small pieces (the melting time is reduced) of bitumen, which, by the way, is easily crushed.

It is good to use a funnel made of thick paper for this purpose, or the upper part of a plastic container with a suitable neck diameter.

The following methods for producing petroleum bitumen are used: atmospheric-vacuum distillation of crude oil to obtain a residue called tar, which, during the processing of highly resinous oils, is residual bitumen; oxidation of oil residues - with tar, cracking residues with atmospheric oxygen, while obtaining oxidized bitumen; mixing of residues resulting from oil refining, deasphalting bitumen with extracts from the purification of oil fractions - the process of obtaining bitumen compounding.

There are also combinations of the above methods.

Production of residual bitumen. Residual bitumens have a number of positive properties and their production is widespread in many countries.

The raw materials for them are fuel oil, tars, as well as other resinous residues formed during distillation. At atmospheric-vacuum membrane of highly resinous oil, residual bitumen is obtained as a residue after the selection of fuel and oily fractions.

During the distillation of oil with a lower content of resinous substances, a less viscous residue is obtained, the properties of which meet the requirements for liquid road bitumen grades MG 70/130, MG 130/200.

Production of oxidized bitumen. The production of bitumen by oxidation is one of the most common methods.

This method can be used in the processing of both resinous and low-resin oils and obtain high-quality road, construction and special bitumen. Unlike other methods (distillation extraction), when asphalt-resin components hardly change, significant changes in their qualitative and quantitative compositions occur during oxidation.

Oxidation is an exothermic process.

The main factors influencing the process of tar oxidation are the initial tar softening temperature, as well as the temperature and duration of oxidation, and air consumption. Oxidized bitumen is obtained mainly from plants using oils rich in light fractions. In this case, methods of periodic oxidation or continuous oxidation in tubular coils are used. Crude oil is subjected to fractional distillation in an atmospheric-vacuum tubular installation.

The resulting residue (tar) with a softening point of 32 - 40 ° C enters the oxidizing bitumen plant.

In the process of oxidation, oxygen interacts with the tar to its components - a dehydro-polycondensation reaction occurs, leading to the formation of high-molecular components.

With an increase in the oxidation temperature from 210 to 250°C, the extensibility of bitumen and the depth of penetration of the needle increase, and above 250°C, these indicators decrease accordingly.

Thus, by changing the oxidation temperature and its duration, it is possible to control the properties of the resulting bitumen.

Depending on the raw material, temperature and the required grade of bitumen, oxidation is carried out within 4-60 hours. To intensify the process, the oxidation method is used with stirring or in the state of foam, emulsion.

Large oxidation surface, high degree air contact with a lower stay of the mixture at a high temperature (250 - 300 ° C) change the nature of the oxidative process.

There is also a method for obtaining oxidized bitumen by batch or continuous bitumen oxidation. The feedstock at a temperature of 170-210°C enters the reactor sections, in which turbines are installed rotating in the feedstock - dispersers that suck in and spray air in the oxidized product.

The following catalysts are used to accelerate the oxidation process: chlorides of zinc, copper, iron, aluminum; phosphorus pentoxide, sulfuric acid, sulfides and a number of others.

Obtaining bitumen by mixing (compounding). Mixing or compounding of bitumen is a secondary process of their processing, which is carried out at refineries or at the point of consumption.

Bitumen or resinous residue obtained by distillation, oxidation, extraction does not always meet the requirements for all indicators for road bitumen. In this case, by mixing bitumen with other resinous residues.

To obtain bitumen of the required properties, their mutual mixing or mixing with other resinous residues formed during the processing of oil and oil products is used.

When mixing bitumen of different properties and origin, it is necessary that the mixed components be close in surface tension. Mixing bitumen with tar is possible in a limited amount (15 - 20%).

The uniformity of mixing is checked by the softening temperature of the mixture, which should correspond to the weighted average of the softening temperatures of the constituent components.

The technology for the preparation of mixed bitumens is reduced to heating them to a liquid consistency and mixing. Most liquid bitumen is prepared by mixing.

Recently, large road construction organizations have been using various wastes obtained in the production of coal tar and polymers (bottom residues of polystyrene, coumarone resins), waste from the regeneration of used lubricating oils as additives to bitumen.