RU2562483C9 - Method and device for bitumen production - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the method and device for production of bitumen from oil residues and may be used in oil processing industry for production of bitumens of different brands. The method includes separation of source raw materials into two flows, heating of one flow of raw materials and its oxidation in a reactor, compounding of oxidized and non-oxidized flows to produce a product. At the same time air supplied to the reactor is dispersed, oxidation of a part of the raw materials flow is carried out in hydrodynamic mode of restricted floating of air bubbles, temperature gradient reduction in the reactor is carried out by circulation of the part of fully or partially oxidized flow, and heat is transferred to heat oxidized raw materials, compounding of flows is carried out in a turbulent mixer, and spent gases leaving the oxidation reactor are exposed to catalytic treatment from organic admixtures.

EFFECT: developed method and device differ by increased technical and economic parameters.

67 cl, 11 dwg, 2 tbl, 9 ex

Description

The method and installation for producing bitumen from oil residues, for example, heavy residues of vacuum distillation of fuel oil, extraction products of mineral oils and can be used in the oil refining industry for the production of various types of bitumen.

A known method of producing bitumen, comprising mixing the heavy fraction of the oil extract, which is a by-product of the selective purification of extracts obtained in the process of production of mineral base oils with dimethyl sulfoxide, and raw materials for the production of petroleum bitumen, taken in the ratio, wt%: heavy fraction of oil extract 70-90 and raw materials for the production of petroleum bitumen 10-30. The resulting mixture is oxidized with atmospheric oxygen at a temperature of 230-290 ° C to obtain a product with a needle penetration depth at 25 ° C 2/12 · 0.1 mm. As raw materials for the production of petroleum bitumen, residues of direct distillation of oil, oxidized bitumen and products of selective separation of petroleum products are used (patent application RU 2010153180 A, IPC C10C 3/00, publ. 27.06.2012). The disadvantages of this method are:

- re-oxidation of the oxidized bitumen that is part of the feedstock, leads to an increased content of oxidized components in the final product and an increase in its fragility, worsening the quality of the resulting bitumen;

- a significant difference in the group composition of the compounded products makes it difficult to ensure the stability of the oxidation process, as some groups of components will be over-oxidized and others under-oxidized, which will degrade the quality of the resulting bitumen and may lead to local heterogeneity of its properties at the micro level;

- limited resources of the used heavy fraction of the oil extract obtained in the process of selective purification of mineral oils.

There is also known a method of producing bitumen by oxidation of petroleum feedstock with air at an elevated temperature in an oxidizing column with a dispersion zone separated from the oxidation zone, comprising supplying air to the dispersion zone through a dispersant, characterized in that the crude oil is fed into the dispersion zone, and bitumen is removed from the oxidation zone (RF patent RU 2248387 C10C 3/04, publ. 20.03.2005). The main disadvantage of this method is the inability to control the temperature of the oxidation of raw materials with atmospheric oxygen, since heat is generated during oxidation, leading to adiabatic heating of the reaction mixture, while the oxidation rate of various oxidizable components of the raw material varies to a different degree, which leads to heterogeneity of oxidation along the height of the reactor oxidizing columns.

A known method of producing bitumen, including the supply of petroleum feedstock and air to the oxidation column (oxidation reactor), the oxidation of petroleum feedstock with oxygen in the oxidation column to ensure uniform or close to uniform distribution of the feedstock in the cross section of the oxidation column due to an external heat-shielding shell that prevents heat dissipation from oxidizable raw materials through the side walls of the column body, or an external heater that provides heat to the oxidizable raw materials through the side walls and the column housing, and the exhaust gases from the oxidation of the column, are neutralized in afterburner furnace (specification of a European patent application 201 100 215 A1, IPC C10C 3/04, publ. 30.08.2011). The main disadvantage of this method is the inability to remove heat from the reaction of oxidation of raw materials with atmospheric oxygen from the reaction medium, which is prevented by the presence of an external heat-shielding, preferably sectional shell, which prevents heat from being oxidized from the raw materials through the side walls of the column body, or an external, preferably sectional heater, providing heat to the oxidizable raw materials through the side walls of the column body. The lack of heat removal leads to a deterioration in the quality of bitumen produced, since the oxidation of petroleum feedstock at an increasing process temperature results in bitumen with an excessively high brittleness, which in turn accelerates, for example, the destruction of road surfaces. In addition, the presence of a temperature gradient along the height of the heat-insulated oxidizing column due to the release of heat from the hydrocarbon oxidation reaction leads to heterogeneity in the composition of the resulting bitumen, since the oxidation reactions of various hydrocarbons are accelerated to different degrees with increasing temperature, since different reactions have different activation energies.

A known method of producing bitumen from paraffinic and high-paraffin oils, including vacuum distillation of fuel oil to obtain tar, mixing the resulting tar with raw organic additives, which are concentrates of polyaromatic hydrocarbons and resins of petroleum origin, oxidizing the resulting mixture with atmospheric oxygen at elevated temperature and overpressure, characterized in that the vacuum distillation of fuel oil is carried out with obtaining super-heavy tar with a nominal viscosity of 180-230 s at 80 ° C, with the content aniem paraffinic-naphthenic hydrocarbons are not more than 18 wt.%, more produce a superheavy mixing raw sludge with organic additives to form a conditioned feedstock composition with a viscosity of 60-110 at 80 ° C, containing at least 50% by weight. aromatic hydrocarbons and having a ratio of resins to asphaltene hydrocarbons is not lower than 8: 3 mass. shares (patent RU 2458965 C1, IPC C10C 3/04, the beginning of the patent 08.02.2011). The disadvantages of this method are:

- mixing super-heavy tar vacuum distillation of fuel oil, in which at 18% of the mass. paraffin-naphthenic hydrocarbons contain a large amount of polyaromatic hydrocarbons (their content in a mixture with cyclanes is more than 80% by mass), with concentrates of polyaromatic resins it forms a compounding raw material with a very high content of aromatic hydrocarbons, which requires an increased air consumption for oxidation of hydrocarbons;

- an increase in air consumption leads to additional costs for its compression and additional environmental pollution leaving the oxidation reactor (oxidation column).

The closest (prototype) to the claimed technical solution is a method for producing bitumen, comprising separating the feedstock into two streams, heating one stream and oxidizing it with atmospheric oxygen at an elevated temperature of 220-230 ° C in an oxidation reactor, compounding the oxidized and non-oxidized streams to produce a product , characterized by the depth of penetration of the needle at 25 ° C 40-200 · 0.1 mm, while the weight of the tar obtained by vacuum distillation of fuel oil is used as feedstock (patent RU 2476580 C2, IPC C10C 3 / 04, published February 27, 2013). The disadvantages of this method are:

- limited resources of raw materials for obtaining bitumen, since in addition to heavy tar and other sources of raw materials from deasphalting plants, selective purification of mineral oils, and others;

- there is no obvious heating furnace or heat exchanger due to heat carrier heat for heating the oxidized part of the feed stream, since uncontrolled cooling of the feed determined by climatic conditions will occur during transportation of the tar from the primary oil refining plant to the bitumen plant, which will not allow maintaining the required temperature in the oxidation reactor;

- limiting the oxidation temperature to 220-230 ° C prevents the possibility of obtaining bitumen of various grades, since the quality of bitumen is controlled by changing the productivity of the oxidation reactor, while the contact time of air with hydrocarbons in the feed remains almost unchanged, therefore, the production of the required quality of bitumen is limited only one degree of freedom in the process, which reduces its technological flexibility;

- the lack of necessary, from the point of view of modern environmental standards, purification of exhaust air leaving the oxidation reactor from trapped light oxidation products.

A known installation for producing bitumen, containing a heat exchanger for heating tar, a fan for air supply, a heater for heating air, a cyclone for cleaning exhaust gas from drip entrainment, a spray chamber (oxidizing column), which is made in a hollow body with an annular collector and centrifugal nozzles for dispersion of tar (patent for utility model RU 45386 U1, IPC C10C 3/04, publ. 05/10/2005). The disadvantages of the installation are:

- oxidation of tar drops occurs in the gas phase for a short time of deposition of oxidized tar drops, which reduces the depth of tar oxidation and the quality of the resulting bitumen;

- the deposition of tar drops in countercurrent with the air flow leads to an increase in the diameter of the spray chamber, ceteris paribus;

- small tar drops are carried away with the air stream and overload the cyclone, which leads to a decrease in the degree of air purification in the cyclone and environmental pollution with organic impurities - light tar oxidation products;

- a large consumption of air for tar oxidation - about 30% - due to the high oxygen concentration in the exhaust gas due to the low efficiency of the oxidation column (spray chamber), which increases operating costs for the implementation of the tar oxidation process.

A known installation for producing bitumen, containing an oxidizing column (oxidation reactor) with a hollow body, a bottom, a cover and a dispersant located in the lower part of the oxidizing column, a line for supplying oil to the oxidizing column with a feed pump installed in it, a line for supplying compressed air to the dispersant with a compressed air flow regulator installed in it, a bitumen discharge line from the oxidizing column with the first pumping pump installed in it, an oxide gas exhaust line from the upper part of the oxidizing column, the portion of the oxidizing column body, the internal volume of which during operation of the unit is filled with oxidizable raw materials, is provided with an external heat-shielding, preferably sectional shell, which prevents heat from being oxidized from the oxidized raw materials through the side walls of the column body, or with an external, preferably sectional heater providing heat flow to oxidized raw materials through the side walls of the column body (patent for utility model RU 101709 U1, IPC С10С 3/04, publ. 09/06/2010). The main disadvantage of the installation is the inability to remove the heat of the reaction of oxidation of raw materials with atmospheric oxygen from the reaction medium, which is prevented by the presence of an external heat-shielding, preferably sectional shell, which prevents the heat from being oxidized from the oxidized raw materials through the side walls of the column body, or an external, preferably sectional heater, providing heat to the oxidizable raw materials through the side walls of the column body. The absence of heat removal leads to a deterioration in the quality of bitumen produced, since the oxidation of petroleum feedstock, at an increasing process temperature, allows the production of bitumen with excessively high brittleness, which in turn accelerates, for example, the destruction of road surfaces.

The closest (prototype) to the claimed technical solution is a plant for producing bitumen, including a tubular furnace with a coil, an oxidation reactor, a pump for supplying raw materials with suction and discharge pipes, a raw material pipe connecting the pump discharge pipe with the inlet of the pipe furnace coil, a pipe connecting coil outlet of the tube furnace with the upper part of the oxidation reactor, a pipe connecting the upper part of the oxidation reactor with the exhaust air afterburner, air distributor located at the bottom of the reactor, a compressor connected by a pipeline to the air distributor and a pipeline for removing bitumen from the oxidation reactor (Oil and gas business in 6 volumes, edited by AM Shammazov; volume 4. Akhmetov AF, Kondrashova NK, Gerasimova E.V. Basics of oil refining, St. Petersburg, Nedra, 2012, pp. 197-199; Oil and gas processing technology, part 1; Methods for producing oil bitumen).

The main disadvantages of the installation are:

- the impossibility of optimal functioning of the main apparatus of the installation - the oxidation reactor, since the intensification of the process requires the creation of the maximum possible phase interface in the countercurrent system of the flow of oxidized hydrocarbons, descending down the oxidation reactor, with air bubbles rising up; however, the size of the air bubble is unregulated and cannot be less than a certain limiting value at which the countercurrent phase velocities are equal, which will lead to flooding of the oxidation reactor;

- the contact time of the air bubble with the liquid phase is limited by the rate of bubble rise and the height of the liquid layer in the oxidation column, because of which the oxygen in the air bubble is not completely consumed for hydrocarbon oxidation, which leads to the need to increase the air supply to the oxidation reactor, increasing energy consumption for air supply from 10%, if the final concentration of oxygen in the air leaving the oxidation reactor is 2% vol., and up to 30%, if the final concentration of oxygen in the air leaving the oxidation reactor laziness is 6% vol .;

- the inability to implement a flexible technology for producing bitumen of various grades due to the instability of the temperature regime of the oxidation reactor, since with the evolution of heat from the oxidation of hydrocarbons with oxygen, the temperature of the reaction mixture will increase uncontrollably along the height of the column from the bottom up, and the oxidation reaction will also increase, moreover, to varying degrees for various oxidizable hydrocarbons, which leads to a violation of the uniformity of the properties of local volumes of bitumen produced;

- the presence of a hydrocarbon afterburning furnace that is carried away from the oxidation reactor with the exhaust air, capable of providing a modern environmental level only with a significant decrease in the technical and economic parameters of the installation, since the thermal disposal of the exhaust air in the afterburning furnace occurs at a high temperature of 1200-1500 ° C, which requires supplying a large amount of fuel gas in the afterburner;

- the need for a significant change in the technological parameters of the installation when changing the characteristics of the feedstock, since the process of oxidation of hydrocarbons by atmospheric oxygen in this installation has only one degree of freedom - the consumption of oxidizable raw materials.

The objective of the invention is to develop a method and installation for producing bitumen, characterized by improved technical and economic indicators, the possibility of expanding the range of raw materials used, the use of technological modes of operation and design features of the apparatus, ensuring the intensification of processes occurring in the main apparatus of the installation.

To solve this problem, a method for producing bitumen is proposed, including the separation of the feedstock into two streams, heating one feed stream and oxidizing it with atmospheric oxygen at an elevated temperature in the oxidation reactor, compounding the oxidized and non-oxidized streams to produce a product in which air is supplied to the oxidation reactor dispersed, the oxidation of a part of the feed stream with atmospheric oxygen at an elevated temperature in the oxidation reactor is performed in the hydrodynamic mode of cramped floating air bubbles, a decrease in the temperature gradient in the oxidation reactor is carried out by circulating part of the fully or partially oxidized stream and heat is transferred to heat the oxidized raw material, compounding the oxidized and non-oxidized streams with bitumen production, characterized by a needle penetration depth at 25 ° C of 20-220 · 0.1 mm are produced in a turbulent mixer, and the exhaust gases leaving the oxidation reactor are subjected to catalytic purification from organic impurities.

Under the hydrodynamic regime of cramped bubbling of air bubbles, the continuous phase of oxidized bitumen forms a thin film between adjacent air bubbles, which reduces diffusion resistance when the oxidizer (oxygen) moves into the volume of bitumen; moreover, a decrease in the speed of cramped bubbling of the air bubble leads to an increase in contact time, all other conditions being equal bitumen film with air bubble. Both of these factors positively affect the chemistry of bitumen oxidation and intensify this process.

Dispersing the air supplied to the oxidation reactor to produce air bubbles of the same diameter helps to create uniform dispersion in the gas-liquid system, which ensures stabilization of hydrodynamic factors in the system. At the first stage of dispersion of the air oxidation supplied to the reactor, it is necessary to ensure the size of the formed air bubbles so that they float in the liquid in the lower part of the oxidation reactor in a turbulent or, at least, in transition mode, providing bubbler mixing of the liquid in this part of the reactor. It is advisable to disperse the air supplied to the oxidation reactor with nozzles or directly in the bubbler holes, while the diameter d of the holes in the bubbler should be no less than that determined by the formula d = (Ar · µ ² / ρ ² · g) ^1/3 , where µ (Pa · s) and ρ (kg / m ³ ), respectively, are the viscosity and density of the oxidizable flow, g is the gravitational acceleration (9.81 m / s ² ), Ar is the Archimedes criterion (Ar is more than 20,000 to ensure a stable transition regime of a gas bubble floating), and the number of holes in the bubbler N is no more than divided by the formula N = 0.732 · Q · ρ / (d · µ · (Ar) ^1/2 ), where Q is the air flow into the reactor (m ³ / s).

To ensure the initial uniform distribution of air bubbles over the cross section of the oxidation reactor and by reducing the hydraulic resistance when moving air from the inlet to the farthest hole in the bubbler, the bubbler has collectors interfaced with bubblers and is made in the shape of a figure that completely repeats the bottom shape of the oxidation reactor vessel, and all openings in them are equidistant from each other and from the wall of the oxidation reactor vessel.

It is advisable to reduce the temperature gradient in the oxidation reactor by providing the circulation of oxidized bitumen, returning it to the reactor. In this case, the downward velocity of oxidizable bitumen in the oxidation reactor increases. This leads to a vortex of this flow, intensification of the process of mixing the medium in the oxidation reactor, and due to the inverse transformation of the kinetic energy of the flow into potential, air bubbles are crushed. As a result, their size decreases, the interface between the phases increases in the gas-liquid system, the rates of ascent of air bubbles in the liquid decrease, the concentrations of air bubbles in the liquid phase increase, which leads to the transition of the hydrodynamic regimes of ascent of particles: from the mode of ascent of single particles to the mode cramped floating particles, in which the floating speed is significantly lower than that of single particles.

So, for example, when the porosity of the inhomogeneous gas-liquid system decreases from 0.9 to 0.7, the rate of cramped ascent of air bubbles decreases 3.8 times, causing the appearance of air bubble circulation and the formation of direct-flow movement of air bubbles together with the liquid phase in reactor volume. This leads to an increase in the duration of contact of air bubbles, a decrease in the diameter and an increase in the interface, which accelerates the transition of oxygen molecules from the volume of the air bubble to the interface and accelerates the reaction of tar oxidation as a whole. As a result, cramped ascent of the bubbles shortens the reaction time and increases the productivity of the reactor or reduces its size.

Thus, the circulating oxidized bitumen simultaneously aligns the temperature of the reaction medium with the height of the oxidation reactor, causing a decrease in the temperature gradient in the reactor, and intensifies the oxidation process.

In this situation, it is advisable to circulate the completely or partially oxidized stream to cooling, while the temperature gradient in the oxidation reactor can be controlled both by the flow rate of the circulated cooled completely or partially oxidized stream, and by the temperature of the circulating cooled completely or partially oxidized bitumen.

For a more precise regulation of the technological regime of the reactor and maintaining a given gradient of temperature changes along the height and cross section of the reactor, which is the basis for the production of high-quality bitumen, it is advisable to provide fractional circulation of the fully or partially oxidized stream, taking it from the reactor from one or more zones and returning it separate streams, but not less than one, in different positions along the height of the oxidation reactor with preliminary cooling. In this case, the regulation of the temperature gradient along the height of the oxidation reactor is provided by changing the flow rate of the circulating fully or partially oxidized stream supplied to various positions along the height of the oxidation reactor, or by changing the temperature of the circulating fully or partially oxidized bitumen supplied to various positions along the height of the oxidation reactor.

To ensure a high level of mixing of unoxidized and oxidized streams of raw materials, it is advisable to use diaphragm disks or an injector, and in the latter case, an unoxidized stream must be used as a working fluid if its flow rate for generating a given quality of tar is greater than the flow rate of the oxidized stream. An oxidized stream is used as such if its flow rate is required to be kept greater than the flow rate of the unoxidized stream.

It is advisable to exit the exhaust gases from the oxidation reactor by removing hydrocarbons in the separator by cooling with a circulating black diesel fuel and then utilizing these gases in the afterburner while heating the coolant, or carry out catalytic purification of organic impurities.

It is advisable to comply with modern environmental standards, the exhaust gases leaving the reactor should be subjected to deep catalytic purification from organic impurities with the formation of carbon dioxide and water, which allows for the neutralization of exhaust gases at its exit temperature from the reactor. Due to the high level of bitumen absorption of oxygen from air bubbles in the present invention, the concentration of oxygen in the exhaust gas may be insufficient to cause deep catalytic oxidation of organic impurities in the exhaust gas. In this case, it is necessary to mix the exhaust gases from the oxidation reactor before catalytic purification with fresh air in the ratio 1: (0.1-0.005), which ensures the operation of the oxidation reactor with a sufficiently high coefficient of excess air relative to oxidizable organic impurities and, accordingly, provides intensification of the oxidation reaction. The exhaust gases are subjected to catalytic purification from organic impurities in a plate-catalytic reactor at a temperature of 150-200 ° C, while using platinum or palladium as a catalyst. If you use cheaper catalysts based on oxides of copper, chromium, iron, zinc, barium, or a mixture of these oxides, then the exhaust gas leaving the reactor is additionally heated in the furnace by burning fuel gas or in the heat exchanger due to the heat carrier to a temperature of 250-350 ° C.

The proposed method for producing bitumen allows the use of high vacuum tar distillation oils of various oils, heavy products of the selective separation of hydrocarbons, heavy extracts of the production of mineral oils or mixtures thereof as feedstock.

The quality of the produced bitumen will be ensured by four degrees of freedom in regulating one of the main indicator of bitumen quality - the depth of penetration of the needle in the resulting product - by varying the following parameters:

- the residence time of the oxidizable portion of the feed stream in the reactor;

- temperature in the oxidation reactor;

- the residence time of the oxidizable portion of the feed stream in the reactor and the temperature in the oxidation reactor;

- the ratio of oxidized and non-oxidized streams of raw materials.

This allows you to receive road, construction, roofing bitumen as a product.

The proposed method allows the simultaneous production of several types of high-quality bitumen, including road, building and roofing bitumen for each type of them, through the use of several parallel reactors that can be the same (universal) or made individually for a particular brand of bitumen.

So, for a milder regime for developing a brand of road bitumen, it is sufficient to perform two-stream circulation of oxidized bitumen (Fig. 3). For a brand with an average mode, the reactor can be with three-stream circulation and additional cooling of one of the recycles (Fig. 6). For a brand with a hard regime - a reactor with three cycles can be retrofitted with a stirrer.

It is advisable to heat the feed stream, which is further oxidized in the reactor, either in heat exchangers due to heat of the coolant or in the coil of the tube furnace with partial air supply, which will partially oxidize hydrocarbons before entering the reactor and additionally relieve the oxidation reactor from the gas phase.

It is advisable to heat the stream supplied to the oxidation of raw materials in heat exchangers arranged in series: first, in the heat exchanger due to the heat of the heat carrier heated in the afterburner by utilizing the exhaust gases, then in the heat exchanger due to the heat of the oxidized product and then in the heat exchanger due to the circulation heat irrigation reactor oxidation.

The elevated temperature in the oxidation reactor should not exceed the temperature of the onset of evaporation of bitumen T _And at a specific absolute pressure in the apparatus P _A and partial air pressure P _P determined from the condition:

X _i is the concentration of the i-th fraction in bitumen;

P _i - saturated vapor pressure of the i-th fraction in bitumen.

To solve this problem, it is proposed to implement the proposed method in a plant for producing bitumen, including a tubular furnace with a coil, an oxidation reactor, a pump for supplying raw materials with suction and discharge pipes, a raw material pipe connecting the pump discharge pipe with the inlet of the pipe furnace coil, a pipe connecting the outlet coil of a tube furnace with an upper part of the oxidation reactor, an air distributor located at the bottom of the reactor, a compressor connected to a distribution pipe an air separator and a pipeline for withdrawing bitumen from the oxidation reactor, while the installation is additionally equipped with a turbulent mixer of the oxidized product and non-oxidized raw materials, a catalytic purification reactor emerging from the oxidation reactor of exhaust gases connected by pipelines, respectively, with fittings for the output from the oxidation reactor of the oxidized product and exhaust gases , the main part of at least one oxidation reactor is a reaction space where the oxidizable feed is in contact oxygen diffusing from the volume of air bubbles to the interface, and the upper part of the reactor is a separation space in which the bitumen is separated from the air, the oxidation reactor is equipped with a bypass pipe connected to the discharge pipe of the pump for supplying raw materials, on the one hand, and on the other hand with a turbulent mixer, the oxidation reactor is equipped with an additional circulation pump connecting the suction pipe to the lower part of the oxidation reactor and the discharge pipe, at least one or more circulation circuits on which recirculate refrigerators are installed, the outputs of the circulation circuits are connected to the oxidation reactor, the oxidation reactor vessel in the middle part consists of several zones, each of which in the course of the fluid flow has sequentially diffuser, cylindrical and confuser configurations.

Zonal execution of the oxidation reactor, with each of the zones along the fluid flow having sequentially diffuser, cylindrical and confuser configurations, which ensure the creation of circulation flows within individual zones in which the mutual conversion of the kinetic and potential energy of the stream is carried out, leading to crushing of air bubbles and an increase phase separation, which ultimately increases the integral rate constant of the oxidation of hydrocarbons by atmospheric oxygen oxidation actor, slows the rate of rise of air bubbles in the liquid phase and increases the completeness of the use of oxygen in the oxidation of hydrocarbons. In the confusional part of the zone, the potential energy of the liquid stream passes into the kinetic one, causing crushing of the air bubbles, their capture by the liquid flow, and the creation of the region of circulation of air bubbles within the unit zone of the oxidation reactor. In the cylindrical part there is an additional crushing of air bubbles due to the friction forces increased due to an increase in the flow velocity. In the diffuser part of the zone, the kinetic energy of the flow again turns into potential, contributing to the formation of vortices in this part of the zone. In general, in a separate zone of the oxidation reactor, a natural formation of a stable internal circulation toroidal contour of the gas-liquid system occurs, which ensures both the crushing of air bubbles and the creation of a fairly uniform dispersion of the reacting system.

It is advisable to additionally connect the compressor to the inlet of the coil of a tubular furnace or a heat exchanger for heating the raw materials at the point where the heated feed stream enters it, which will ensure mixing of air with the heated raw materials and lead to partial preliminary oxidation of the raw materials directly in the coil of the tubular furnace, which will reduce the specific load of the reactor oxidation and will increase the productivity of the installation for bitumen.

It is advisable that the raw material pipeline is connected to a heat exchanger, which heats the feedstock due to the heat carrier heated in the afterburner by utilizing the exhaust gases, then the pipeline is connected to a heat exchanger, where heating is due to the heat of the oxidized product, after which the pipeline is connected to the heat exchanger due to heat circulation irrigation reactor oxidation.

It is advisable that the number of oxidation reactors corresponds to the number of simultaneously produced grades of one type of bitumen or the number of different types of bitumen.

It is also advisable to perform the oxidation reactor of variable diameter so that the diameter of the separation part of the oxidation reactor becomes greater than or equal to the diameter of the reaction space of the oxidation reactor. This will drastically reduce foaming in the upper part of the reactor, eliminate dripping liquid and reduce the likelihood of solid stalagmites forming from tar oxidation products in the upper part of the oxidation reactor vessel and the pipeline connecting the reactor to the exhaust gas purification system, which can block the live section for the passage of oxidation gases .

It is advisable that the fully or partially oxidized stream exit to the circulation loop, designed to return the cooled completely or partially oxidized stream to the oxidation reactor, in the cylindrical part of the vessel above or below the interface with the diffuser and confuser configurations of the oxidation reactor vessel.

It is advisable to connect the input of the circulation circuit to the oxidation reactor at the interface between the diffuser and confuser configurations of the oxidation reactor vessel along the axis of the normal section of the vessel or tangentially to the vessel. This allows one to intensify the natural formation of a stable internal circulating toroidal contour of the gas-liquid system, which provides the crushing of air bubbles required for the reaction and the creation of a uniform and uniform dispersion of the reacting system.

For large diameter oxidation reactors, a single normal or tangential connection of the circulation circuit to the oxidation reactor weakens the formation of a stable internal circulation toroidal circuit of the gas-liquid system, which ensures both the fragmentation of air bubbles and the creation of a fairly uniform dispersion of the reacting system. In this case, it is advisable that the inlet of the circulation circuit be made in the form of an external annular collector interfaced with the oxidation reactor at the interface between the diffuser and confuser configurations of the oxidation reactor vessel, while the external ring collector is connected by tangential nozzles to the oxidation reactor vessel. In this case, the tangential nozzles of the outer annular collector are located equidistant or concentrated on one or more sections. In this case, the external annular collector is interfaced to the oxidation reactor vessel, and the internal annular collector is located inside the oxidation reactor, and the collectors are located at the interface between the diffuser and confuser configurations of the oxidation reactor vessel, while the pipes of the external and internal annular collectors tangentially communicate with the internal space of the oxidation reactor vessel .

It is advisable that the air distributor had collectors interfaced with bubblers, which will reduce the hydraulic resistance of the bubbler device and increase the uniformity of the initial air supply to the oxidation reactor over its cross section, while the diameter of the holes in the bubbler device d is not less than d = (Ar µ ² / ρ ² · g) ^1/3 , where µ (Pa · s) and ρ (kg / m ³ ), respectively, are the viscosity and density of the oxidized flow, g is the gravitational acceleration (9.81 m / s ² ) , Ar is the Archimedes criterion, and the number of holes in the bubbler device N is greater than N = 0.732 · Q · ρ / (d · µ · (Ar) ^1/2 ), where Q is the air flow into the reactor (m ³ / s). In this case, it is possible to ensure such a size of the formed air bubbles that they float in the liquid in the lower part of the oxidation reactor in a turbulent or at least in transition mode, providing bubbler mixing of the liquid in this part of the reactor.

It is also advisable that when mixing the oxidized and non-oxidized part of the feed, an injector should be used as a turbulent mixer, the supply line of the working fluid to the injector being connected to the bypass supply line of the non-oxidized stream at an oxidized flow rate less than the non-oxidized stream, and the liquid suction line to the injector should be connected with an oxidized flow feed line to the bottom of the oxidation reactor or a line for supplying a working fluid to the injector connected to the oxidized flow line with the lower part of the oxidation reactor, when the flow rate of the oxidized stream is greater than the unoxidized stream, and the suction line of the liquid into the injector is connected to the bypass supply pipe of the unoxidized stream, which will ensure the utmost full use of the energy of the mixed flows, it is also possible to use a diaphragm mixer with a turbulent mixer diaphragm discs. Intensive mixing of the two flows in the injector is ensured due to the fact that a higher flow rate enters the apparatus through the working fluid supply line, then, due to an increase in its speed, it intensifies the turbulization of the working fluid and creates a vacuum in the suction line. The lower flow rate is sucked into the turbulent flow of the working fluid with intensive mixing of the two flows. In a diaphragm mixer, a series of disks with round holes (diaphragms) are installed in the mixer body, and when mixed flows pass from one disk to another, a sequential local increase and decrease in the flow velocity occurs with a sequential conversion of the kinetic energy of the flows into potential, and, conversely, with intensive turbulization of local liquid jets, providing intensive mixing of two flows

Depending on the real features of the thermocatalytic purification of organic impurities exhausted in the gas oxidation reactor, it is advisable that the catalytic air purification reactor be a casing in which a stack of plates is installed, on the surface of which a catalyst coating layer is applied, while the casing of the catalytic purification reactor is in normal section may have a square, rectangular or round shape, or the catalytic purification reactor was a package of plates onto the surface of which the catalyst coating layer is mounted directly in the pipeline connected to the top of the oxidation reactor, which reduces the metal consumption of the catalytic treatment reactor.

It is advisable to install a separator on the pipeline connecting the top of the oxidation reactor with the catalytic treatment reactor, which will allow separating hydrocarbon impurities in the form of a dispersed phase from the exhaust gas stream, which will reduce the load of the catalytic treatment reactor for hydrocarbon oxidized to carbon dioxide and water and reduce its size. In cases where the catalyst coating layer of the plate pack of the catalytic treatment reactor is based on low-cost oxide catalysts that require the process of thermocatalytic treatment of exhaust gases at temperatures of 250-350 ° C, it is advisable to install an exhaust gas heater in front of the catalytic treatment reactor, which can be a furnace or a heat exchanger with a coolant supplied to it, an additional coil of the convection chamber of a tubular furnace, for example, designed to heat the coolant and installation.

It is also advisable to install an anchor mixer in the lower part of the separation part of the oxidation reactor, which will remove a layer of resinous deposits adhering to the walls of the separation part of the reactor, preventing the formation of stalagmites, and return them to the reaction zone of the oxidation reactor.

It is also advisable to further intensify the mixing of the heterogeneous liquid-gas system in the oxidation reactor in order to avoid coalescence of air bubbles due to the fact that in each of the zones of the middle part of the oxidation reactor having a sequentially diffuser, cylindrical and confuser configuration, a mixing device is placed. The mixing device may be a propeller stirrer that provides a downward circulation of the oxidizable feed: air system in the oxidation reactor, which, in addition to the effect of the oxidized tar recycling, will increase the residence time of air bubbles in the oxidation reactor and lead to a reduction in the duration of the oxidation reaction or the possibility of increasing reactor productivity ; to form a stable circulation of air bubbles, the propeller stirrer can be placed in the guide cylinder. The mixing device may also be a disk mixer, providing radial mixing of the oxidizable feed-air system.

The invention is illustrated in the drawing, where figure 1 shows a diagram of the proposed installation for producing bitumen according to the proposed method for producing bitumen.

The installation diagram for producing bitumen contains the following positions: pump 1 with suction and discharge nozzles; oven 4 with a coil 5; oxidation reactor 6, consisting of a separation section 7 and a reaction section 8, which is formed of several identical or different sizes of the reaction zones 9, each of which has (from bottom to top along the air flow) confuser 10, cylindrical 11 and diffuser 12 configurations; inside the cylindrical part 11 of the reaction zone 9 is placed a stirrer 13; in the lower part of the separation section 7 is a frame mixer 14; a bubbling device 15 is placed in the lower part of the reaction section 8; compressor 16; circulation pump 17; circulation circuits 18 with heat exchangers 19; a separator 20 with a refrigerator 2, a thermocatalytic reactor 21, a turbulent mixer 3, and a piping system 22-35.

The main apparatuses of the scheme of the proposed installation for producing bitumen are connected by pipelines as follows: the feedstock pipe is connected to the suction pipe of the pump 1. The discharge pipe of the pump 2 is connected by a pipe 24 to the inlet of the coil 5 of the furnace 4 and the pipeline of the bypass line 25. The output of the coil 5 of the furnace 4 is connected by a pipe 26 with the upper part of the reaction section 8 of the oxidation reactor 6. The pipe 27 connects the compressor 16 to the bubbler device 15 of the oxidation reactor 6. The separation section 7 of the oxidation reactor 6 at the top of the conduit 28 is connected with a separator 20. The bottom is connected to the condenser 2, after which the part of the separator 35 conduit 20 conduit 22 connected to the upper part of the separator 20 and conduit 29 with black diesel fuel storage tanks (not shown). The upper part of the separator 20 by a pipe 30 is connected to the inlet of the thermocatalytic reactor 21, the output of which by a pipe 31 is connected to a system for dumping purified gases into the atmosphere (not shown). The lower part of the reaction section 8 of the oxidation reactor 6 is connected to the circulation pump 17 and the piping system forms the circulation circuits 18 of the heat exchangers 19; the lower part of the reaction section 8 of the oxidation reactor 6 is connected by a pipe 32 to the input of the turbulent mixer 3. The bypass line 25 is also connected to the input of the turbulent mixer 3. The output of the turbulent mixer 3 is connected by a pipe 33 to the prepared bitumen storage tank (not shown).

The proposed method for producing bitumen is implemented in this installation as follows: the feedstock (tar after vacuum distillation of heavy fuel oil, heavy residues of selective oil refining, etc.) is supplied through pipeline 23 to the installation for the production of bitumen and pump 1 through pipeline 24 is recycled this part of the feed stream is directed through the coil 5 of the furnace 4 to the oxidation stage, and the second, non-oxidizable part of the feed stream through the bypass pipe 25 is sent to a turbulent mixer 3 for mixing with the oxidized part of the stream raw materials. The ratio of the oxidized and non-oxidative parts of the feed stream can range from 9: 1 to 2.3: 1 and is determined by two factors: the composition of the feedstock and the quality requirement of the resulting bitumen, which depending on the grade may have a needle penetration depth at 25 ° C in the range of 20-220 · 0.1 mm. In the tube furnace 4, the oxidizable part of the feed stream is heated to a temperature of 180-230 ° C (depending on the grade of bitumen being produced) and is fed through a pipe 26 to the upper part of the reaction section 8 of the oxidation reactor 6, to the bottom of which is a compressor 16 through a pipe 27 and through a bubbler device 15 is supplied with air. In the oxidation reactor 6, countercurrent contact occurs between the oxidizable feed and oxygen in the air, passing from the volume of air bubbles to the interface. The separation of the reaction section 8 of the oxidation reactor 6 into several identical reaction zones 9, each of which has (from bottom to top) a confuser 10, a cylindrical 11 and a diffuser 12 configuration with a stirrer 13 inside the cylindrical part 11 provides intensive mixing of the oxidizable raw materials and dispersed air in it, prevents unwanted coalescence of air bubbles and contributes to the additional fragmentation of air bubbles into smaller ones, which contributes to an increase in the interface and integral velocity and oxidation reactions, leading to shorter reaction time and opportunity thereby increasing plant capacity. Since heat is generated during the oxidation of hydrocarbons by oxygen, leading to the presence of a temperature gradient along the height of the oxidation reactor 6, the result of which is a different degree of intensification of numerous simple oxidation reactions of specific raw materials components along the height of the oxidation reactor 6, since, according to the Arrhenius equation, the reaction rate constants with different activation energies vary with temperature differently. The result of the presence of a temperature gradient is a local heterogeneity of the oxidizable product in terms of component composition, which is reflected in the fluctuations in the analysis results of such an important indicator for bitumen as the penetration depth of the needle. An ideal thermal condition for obtaining a uniform bitumen would be to carry out the oxidation process under isothermal conditions. The proposed scheme for tying oxidation reactor 6 with a circulation pump 17 and a piping system that forms circulation circuits 18 with heat exchangers 19, which allow cooling the circulating oxidized product and introducing it, if necessary, into each of the reaction zones 9, reduces the temperature gradient in the oxidation reactor 6 from 30-40 ° C to 1-2 ° C. The exhaust gases after separation from the foamed liquid phase in the separation section 7 of the oxidation reactor 6 with a temperature of about 200 ° C through a pipe 28 enter the separator, in which the dispersed phase carried away by air is separated, part of it is fed through the refrigerator 2 to the separator as cold irrigation, and the balance amount is discharged through the pipeline 29 to the storage tanks of black solarium, and the exhaust gases containing hydrocarbon vapors go through the pipeline 30 to the plate type thermocatalytic reactor 31 with a catalyst a coating on the surface of wafers based on an aluminosilicate carrier with a platinum content of 0.4-0.5%, providing complete oxidation of the hydrocarbon vapors contained in the exhaust gas to carbon dioxide and water. The oxidized part of the raw material is mixed with the non-oxidized part of the raw material in the turbulent mixer 3. In order to intensify the oxidation process, it is provided that the compressor 16 supplies part of the air through line 34 for mixing with the feed stream heated in the furnace 4, which creates the effect of pre-oxidation of this product.

Figure 2 presents the installation for producing bitumen, which differs from figure 1 in that the feedstock fed to the oxidation is heated in the heat exchanger system 36, 37 and 19, respectively, due to the heat of the coolant, the oxidized product supplied through the pipe 32 and partially oxidized stream used as a circulation loop 18. In addition, an afterburner 4 is used, in which, when the exhaust gases are burned, heat is used to heat the coolant. The operation of the reactor is carried out without the use of a mixing device, the output of circulating irrigation, partially oxidized raw materials, is produced from various zones of the reactor.

Figures 3-5 show embodiments of oxidation reactors. The figure 3 provides a dual-stream circulation of the oxidized stream. This oxidation reactor does not provide a mixing device. It is advisable to use this reactor in the presence of raw materials, allowing to produce various grades of bitumen under mild conditions.

To maintain the desired value in terms of bitumen porosity, the design of the oxidation reactor is such that the diameter of the upper part of the reactor is larger than in the lower part (Fig. 4). The separation zone 7 of the oxidation reactor provides for the use of a mixer 14, which allows to rake away entrained particles of the oxidized product from the walls of the reactor and return it back to the reaction zone 8.

It is also possible to use a bubbler in the oxidation reactor, which is made in the shape of a figure repeating the shape of the bottom of the oxidation reactor vessel, with all openings in them equally spaced from each other and from the walls of the oxidation reactor vessel (Fig. 5).

The figure 6 presents a schematic diagram of the installation for obtaining three grades of bitumen in one installation at the same time. On the diagram: 2 - refrigerator; 3 - turbulent mixers; 6 - oxidation reactors; 16 - compressor; 17, 41, 53-55, 64-66 - pumps; 19 - heat exchangers; 20 - separator; 21 - thermocatalytic reactor; 40, 68-70 - containers; 43 - air separator; 44-46 - in-line mixers; 47-49 - socking section; 56 - freight fleet or loading rack; 61-63 - heat exchangers; 39 - pipeline supply of raw materials; 42 - air supply pipe; 58-60 - pipelines for the supply of various additives; 67 - purified gas pipeline; 57 - black solarium; 50-52 - pipelines of various grades of bitumen; solid lines - pipelines for pumping liquid and gas phases.

The installation works as follows: the feedstock is divided into two streams - a stream of oxidizable raw materials and a stream of non-oxidizable raw materials. The oxidized raw material enters through the pipeline 39 into the tank 40, from where it is pumped and distributed by the pump 41 into three oxidation reactors 6, in each of which the necessary temperature conditions, air flow and oxidation time are maintained in accordance with the technology for producing a particular brand of bitumen. The air supplied to the installation through line 42 is pre-compressed in compressor 16, then passes through an air separator 43 and distributed to three oxidation reactors 6. If necessary, additives can be used to achieve the desired properties of the required grade of bitumen, which are supplied through lines 58-60, then they are mixed with the feedstock in 44-46 in-line mixers, then the mixture is sent for heating to the heat exchangers 61-63 through tanks 68-70 and pumps 64-66 and enters the oxidation reactors 6. Oxidation reactors 6 sn are removed by a circulation pump 17 and a heat exchanger 19, which allows cooling the circulating oxidized product. After the oxidation reactor 6, the oxidized part of the feed is fed to the mixers 3, in which the mixture is mixed with the required amount of the non-oxidized part of the feed, providing the standard parameters of the produced grades of bitumen. After passing mixers 3, the mixture is sent to the socking sections 47-49, from where various bitumen is produced: grades 50-52 are pumped through pumps 53-55 and sent to the freight fleet 56. The exhaust gases from the oxidation reactors together with the gases from the socking sections sent to the separator 20, from the top of which they are cleaned in the thermocatalytic reactor 21 and removed from the installation via pipeline 67, from the bottom of the separator, a black solarium is withdrawn via pipeline 57 either to the fuel oil pipeline or to the tank farm (not shown).

The proposed method and installation for producing bitumen is illustrated by the following examples.

Example 1. At the column stand on the system "water-air" were simulated hydrodynamic features of the oxidation reactor according to the prototype. The column consisted of a tank (column cube) and three transparent sections with a diameter of 0.4 m and a height of 0.6 m each. The total height of the hollow column was 1.8 m. Thus, the bench apparatus at a scale of 1: 5 imitated one of the industrial oxidation reactors. At the bottom of the column there is a bubbler in the form of a cross with a central hole with a diameter of 0.01 m, which fully corresponds to the parameters of an industrial bubbler. The column was equipped with a compressor providing air supply to the bubbler in the amount of 15.6 m ³ / h, and a pump providing circulating water supply from the cube to the column from 1 to 40 m ³ / h. The hydrodynamic features of the water-air system in the column were recorded by video, which allowed us to record not only the general hydrodynamic state of the system, but also to analyze the local flow structure in characteristic parts of the structure.

An analysis of the hydrodynamic state of the system showed that, in general, in the upper part of the column, a fairly uniform mode of bubbling of air bubbles is maintained; in some places of the fluid flow, small (0.08-0.10 m in diameter) sporadic vortices are randomly moving in the fluid volume (for clarity) they are highlighted graphically, see Fig. 7). In the lower part of the column (Fig. 8), unstable air channels of variable cross section with a diameter of 0.05 to 0.15 m and a length of up to 0.3 m are formed, which begin to disperse into individual bubbles with a height of about 0.5 m from the bubble hole a wide range of bubble diameters from 0.005 to 0.020 m.

In General, the structure of the flows in the column according to the prototype can be characterized as a fairly established mode of free floating of air bubbles in a liquid medium with insignificant circulation zones and with unsatisfactory formation of a homogeneous dispersed system, especially in the lower part of the column, which corresponds to the mode of practically no oxidation in the lower part of the oxidation reactor in relation to the process of oxidation of hydrocarbons due to the presence of air channel formation in a liquid medium, that is, about 1/6 h The column does not work. In general, the hydrodynamic situation in the column corresponds to the regime of ideal displacement in the water and air phases with insignificant unstable zones of circulating vortices.

Example 2. At the column stand on the system "water-air" were simulated hydrodynamic features of the oxidation reactor according to the claimed invention. The column consisted of a tank and three transparent sections with a diameter of 0.4 m and a height of 0.6 each. The total height of the hollow column was 1.8 m. Thus, the bench apparatus at a scale of 1: 5 imitated an industrial oxidation reactor. At the bottom of the column there is a bubbler in the form of a cross with a central hole with a diameter of 0.01 m, corresponding to the parameters of industrial bubblers. The column was equipped with a compressor providing air supply to the bubbler in the amount of 15.6 m ³ / h, and a pump providing water supply to the column from 1 to 40 m ³ / h. In the lower section of the column was mounted a model of the reaction zone, having (bottom to top) diffuser, cylindrical and confuser configuration.

Figure 9a shows the operation of the lower section of the column with a mock-up of the reaction zone when 7.8 m ³ / h of air is supplied; Figure 9b repeats Figure 9a, in which the outline of the structural elements of the reaction zone made of transparent plexiglass is underlined with a dashed line and not clearly visible in figure 9, a, as well as graphically highlighted observed characteristic zones of stable circulation. An analysis of the hydrodynamic state of the system showed that, on the whole, a fairly homogeneous mode of bubbling of air bubbles is maintained in the upper part of the column, small sporadic vortices moving randomly in the volume of the liquid similar to the prototype are noticeable in some places of the fluid flow. In the lower part of the column (figures 9, a, b), the unstable air channels that were previously observed in the prototype (figure 8) disappeared and a fairly uniform dispersed gas-liquid system was formed almost immediately at the air outlet from the bubbler hole. The dimensions of the air bubbles were mainly 0.005 mm. Due to the specific configuration of the reaction zone design, the formation of stable gas-liquid system circulation zones having a toroidal shape was observed, moreover, in the lower confusor part, the circulation in the circulation zone was clockwise in the horizontal plane, in the upper diffuser part, the circulation in the circulation zone was counterclockwise arrows are also in the horizontal plane, and in the cylindrical part, twisting was observed in the vertical plane with a throw of the gas-liquid system from di fuzornoy part in confused. Thus, the constructive implementation of the reaction zone in the form of a pair of confuser, cylindrical and diffuser elements in comparison with the traditional countercurrent of the prototype provides more intensive crushing of air bubbles and more uniform dispersion of air in the liquid phase, which, all other things being equal, leads to an increase in the interface and integral reaction rate constants, which will reduce the reaction time and will increase the productivity of the installation. In addition, the occurrence of toroidal vortex circulation flows in the apparatus leads to a delay in air bubbles in the reaction zone and, consequently, to an increase in the contact time of air bubbles with a liquid, a more complete use of atmospheric oxygen for the oxidation of hydrocarbons and, as a result, reduces air consumption and compression costs.

Example 3. Under the conditions of operation of the column of Example 2, between the lower and middle sections of the column by the circulation pump, water was introduced along the horizontal axis of the column in an amount of 1 to 10 m ³ / h taken from the column cube, thus simulating the operation of the circulation circuit. As follows from figure 10, in which the outline of the structural elements of the reaction zone is underlined with a dotted line, and the observed characteristic zones of stable circulation are graphically highlighted, the hydrodynamic situation in the section remains close to the picture previously observed in example 2, but while maintaining the size of most air bubbles at the level of 0.005 m a noticeable decrease in the porosity of the gas-liquid system is visually observed due to a decrease in the distance between air bubbles and the rate of bubble rise. This phenomenon is explained by the fact that the downward flow of the circulating fluid causes an increase in the friction forces at the interface between the air bubbles and the water directed downward, intensifying local turbulence in thin layers of water in contact with the air bubble, and ultimately reducing the speed of the rise of air bubbles. In relation to the process of bitumen oxidation, this means an increase in the contact time of air and the product being oxidized, while accelerating the transfer of oxygen from the interface to oxidizable hydrocarbons and an increase in the concentration of oxidizable hydrocarbons at the interface, which should substantially intensify the process of oxidation of hydrocarbons. In addition, two additional circulation zones arose in the upper part of the section in the horizontal plane with the rotation of the vortices clockwise in the right vortex and counterclockwise in the left vortex.

Example 4. Under the conditions of operation of the column according to example 3, between the lower and middle sections of the column with a circulation pump, tangential water was introduced along the horizontal axis of the column in an amount of 1 to 10 m ³ / h, taken from the cube of the column, thus simulating another version of the circulation circuit . Air consumption was 15.6 m ³ / h. As follows from figure 11, in which the outline of the structural elements of the reaction zone is dotted and the observed characteristic zones of stable circulation are graphically highlighted, the hydrodynamic situation in the section remains close to the previously observed pattern in Example 3, the size of most air bubbles remained at the level of 0.005 m. air flow led to a decrease in the volume fraction of the apparatus occupied by the liquid, which caused an additional increase in the friction forces at the interface of the air bubbles and water, intensifying local turbulization in thin layers of water in direct contact with the air bubble, and ultimately reducing the speed of floating of air bubbles. In relation to the process of bitumen oxidation, an increase in the liquid flow rate along the circulation circuit will lead to an additional increase in the contact time of air and the oxidized product, acceleration of oxygen transfer from the interface to oxidizable hydrocarbons, and an increase in the concentration of oxidizable hydrocarbons at the interface, intensifying the hydrocarbon oxidation process. In addition, unlike example 3, in the upper part of the section there was one additional circulation zone of the gas-liquid system in the horizontal plane with the rotation of the vortex clockwise due to the tangential introduction of the circulating liquid into the column.

On the whole, the results of the experiments given in Examples 2–4 allow us to consider from the standpoint of hydrodynamics a section of the column (conditional reaction zone) consisting of elements of a diffuser, cylindrical, and confuser configuration as an ideal mixing cell.

Example 5. On the column stand, described in detail in example 2, were simulated hydrodynamic features of the oxidation reactor according to the claimed invention on the system of "an aqueous solution of glycerol - air". According to its physical and chemical properties, the solution used, consisting of 60% by volume of glycerol and 40% by volume of water, is close in viscosity to the tar (raw material of the plant for producing bitumen) under oxidation conditions in the reactor at 220 ° C, in particular, its viscosity is 0, 03 Pa s In the lower section of the column was mounted a model of the reaction zone, having (bottom to top) diffuser, cylindrical and confuser configuration. The column was tested in a number of modes of formation of the circulation circuit with the tangential introduction of an aqueous solution of glycerol. Numerous toroidal vortices and a sharp decrease in the size of part of air bubbles on average to 0.002 m were noted with a very high uniformity of the liquid-gas system, which lost transparency, acquired a milky white color due to the dispersion of the system, which did not allow obtaining information-rich photographs of the work the columns.

The following examples provide a series of calculations illustrating the operation of the plant for producing bitumen.

Example 6. Were calculated hydrodynamic parameters of the oxidation reactor according to the prototype and the claimed invention upon receipt of bitumen from tar at 200 ° C and a pressure of 0.3 MPa. In both calculations, the same unit capacity was adopted for tar 6 t / h and air consumption of 100 m ³ per ton of tar. The density of the tar accepted 1000 kg / m ^{3 the} viscosity at 220 ° C is 0.03 Pa · s. The basis for the calculations based on the prototype was a tar oxidation reactor with a diameter of 2.5 m, a bubble zone height of 10.6 m and a working volume of 52 m ³ . When calculating the reactor according to the claimed invention, 3 reaction zones with a height of 3.5 m were formed in the oxidation reactor, each of which consisted of elements of a diffuser, cylindrical and confuser configuration, which led to a decrease in the reaction volume of the reactor from 52 to 36.7 m ³ . Based on previously performed experiments (examples 1-5), it was assumed that the diameter of the air bubbles in the column according to the prototype was 0.01 m, and in the column according to the claimed invention - 0.005 m. When calculating the hydrodynamics of the devices, the hydrodynamic criteria of similarity between Archimedes and Reynolds were calculated , the rate of rise of air bubbles in the tar, the duration of the rise of air bubbles in the column from the bubbler to the separation zone, the volume occupied, respectively, of the continuous liquid phase (tar) and dispersed gas second phase (air) in a volume of the column, the porosity of the gas-liquid system and the residence time of the liquid phase in the column. The dispersion of the liquid-gas system in the oxidation reactor according to the claimed invention has increased and is approaching the maximum permissible (porosity of the reaction mixture is 0.53), since with a further decrease in porosity it is limited by foaming of the medium. The calculation results are shown in table 1, from which it follows that in the claimed invention, due to better dispersion of air, the contact time of air with tar increases by a factor of 2.64, with a simultaneous similar increase in the amount of contacting air, which should lead to an intensification of the process of tar oxidation and consumption when this is air oxygen.

Example 7. Modeling the operation of the oxidation reactor according to the claimed invention on the basis of example 6. Since the hydrodynamics of the oxidation reactor according to the prototype is close to the ideal displacement model, taking, according to industrial data, the decrease in oxygen concentration in the air in contact with the tar from the reactor from 21 to 5% about. and the estimated contact time of air bubbles with tar 117.8 sec (Table 1) was calculated, according to the mathematical model of the ideal displacement reactor for stationary conditions of its operation, the reaction rate constant for the interaction of oxygen with tar, which amounted to 0.028 s ^-1 for the prototype. Since in the oxidation reactor according to the claimed invention, as shown by experiments (examples 1-4), there is a more intense dispersion of air bubbles with a diameter of 0.005 m versus 0.01 m in the prototype, then, as the calculations showed, in the claimed invention, the interface proportional to the number and diameter of air bubbles, also twice as much as in the prototype. The increase in the interface leads to a corresponding proportional increase in the rate of reaction of oxygen consumption during the oxidation of the tar. This allowed us to take the reaction rate constant of the reaction of interaction of oxygen with tar in the oxidation reactor according to the invention equal to 0.056 s ^-1 . Since each reaction zone of the oxidation reactor containing elements of a diffuser, cylindrical, and confuser configuration is close to the ideal mixing model, the hydrodynamics of the oxidation reactor according to the claimed invention having three such reaction zones can be considered as a cell model for a cascade of three ideal mixing reactors. Using the mathematical model of a cascade of three ideal mixing reactors, taking into account the kinetics of the oxygen consumption reaction during the oxidation of the tar for stationary conditions of the oxidation reactor, the residence time of the reaction system in each section of the reactor was calculated by iteration, which amounted to 103.74 s and the total residence time of air bubbles was determined in the reactor 311.22 s, which is in good agreement with the data of the hydrodynamic calculation of the reactor - 311.7 s (Table 1). In this case, the final oxygen concentration in the exhaust gas stream at the outlet of the oxidation reactor is only 0.0665% vol. against 5% vol. in the prototype, which indicates a greater efficiency of the proposed method for producing bitumen compared with the prototype; an additional advantage is the ability to increase the depth of oxidation of the tar without introducing additional air into the process or reduce air consumption by 19.2% while maintaining the depth of oxidation of the tar.

Example 8. Catalytic purification of organic impurities from the exhaust air from the oxidation reactor in a plate-type thermocatalytic reactor with a catalyst coating deposited on the surface of the plates allows to improve the technical and economic performance of the installation for producing bitumen, since the costs of environmental measures related to the protected environment are practically eliminated . Catalyst coatings containing small amounts of platinum deposited on an inert support provide complete deep oxidation of hydrocarbon vapors that are in the exhaust gas to carbon dioxide and water already at 200 ° C, that is, additional heating of the exhaust gas from 200 ° C is not required up to 1500 ° C for its thermal neutralization in the afterburner at 1500 ° C, which leads to significant fuel savings. So, for the installation for producing bitumen with an air flow rate of oxidation of 600 m ³ / h, considered in Example 6, when the plant is operated for 350 days a year, more than 204 tons of fuel with a calorific value of 8000 kcal / kg will be required for thermal neutralization of the exhaust gas. When using cheap oxide catalysts in a thermocatalytic reactor, additional heating of the exhaust gas after the oxidation reactor from 200 ° C to 330 ° C in the furnace will be required, which will consume only 20 tons of fuel during the year.

Example 9. The main feature of the claimed invention is a large number of degrees of freedom of its functioning, which allows, due to a combination of variable technological parameters, to obtain bitumen of one of the necessary modern grades (table 2) if there is one reactor or several grades of bitumen in the installation for producing bitumen oxidation reactors. The quality of each of the obtained grades of bitumen (for example, road or roofing bitumen) in an installation with several oxidation reactors is ensured provided that the characteristics of the feedstock are constant, at least at least 8 degrees of freedom:

- varying the performance of the oxidation reactor for hydrocarbons;

- varying the flow rate of air entering the oxidation reactor;

- varying the oxidation time of the feed in the reactor;

- the temperature of the process of oxidation of hydrocarbons in the oxidation reactor;

- pressure in the oxidation reactor;

- regulation of the flow of circulating bitumen flows along the height of the oxidation reactor;

- controlling the temperature of the circulating bitumen flows along the height of the oxidation reactor;

- varying the ratio of oxidizable and non-oxidizable parts of the raw materials of the process for producing bitumen;

- regulation of the air supply together with the raw material at the inlet to the furnace coil for preoxidation;

- carrying out the oxidation process of the oxidizable part of the feed in series in two or three oxidation reactors.

In addition, there is an additional ninth degree of freedom, due to the variation in the composition of the raw material due to compounding it from various fractions and / or the use of various additives.

Thus, by improving the method and installation for producing bitumen, the oxygen concentration in the exhaust gas stream at the outlet of the oxidation reactor decreases, the operation of the oxidation reactor is intensified, the technological flexibility of the installation increases, which allows increasing the oxidation depth of the tar without introducing additional air into the process, or reducing consumption air while maintaining the depth of oxidation of the tar, or to produce at the same time a number of different grades of bitumen at the installation, the guarantor increases and reliable development of the desired properties of the required grade of bitumen, including one having the highest requirements for its quality, the technical and economic indicators of the installation are improved due to the cessation of fuel consumption for neutralization of exhaust gas.

Claims (67)

1. A method of producing bitumen, comprising dividing the feedstock into two streams, heating one feed stream and oxidizing it with atmospheric oxygen in an oxidation reactor, compounding the oxidized and non-oxidized streams to produce a product, characterized in that the air supplied to the oxidation reactor is dispersed, oxidation parts of the flow of raw materials with atmospheric oxygen in the oxidation reactor produce in the hydrodynamic mode of cramped floating of air bubbles, a decrease in the temperature gradient in the oxidation reactor produces They use a part of the fully or partially oxidized stream and transfer heat to heat the oxidizable feedstock, compounding the oxidized and non-oxidized streams with bitumen production, characterized by a needle penetration depth at 25 ° C of 20-220 · 0.1 mm, produced in a turbulent mixer, and leaving the oxidation reactor exhaust gases are subjected to catalytic purification from organic impurities. 2. The method according to p. 1, characterized in that the dispersion of the air supplied to the oxidation reactor is carried out in the holes of the bubbler. 3. The method according to claim 1, characterized in that the dispersion of the air supplied to the oxidation reactor is carried out by nozzles. 4. The method according to claim 2, characterized in that the value of the diameter d of the holes in the bubbler should not be less than that determined by the formula d = (Ar · µ ² / ρ ² · g) ^1/3 , where µ (Pa · s ) and ρ (kg / m ³ ), respectively, the viscosity and density of the oxidized flow, g is the acceleration of gravity (9.81 m / s ² ), Ar is the Archimedes criterion. 5. The method according to claim 4, characterized in that the number of holes in the bubbler N is not greater than N = 0.732Q · ρ / (d · µ · (Ar) ^1/2 ), where Q is the air flow in the reactor (m ³ / s). 6. The method according to any one of paragraphs. 2, 4, 5, characterized in that the bubbler has a collector associated with bubblers, and is made in the form of a figure that completely repeats the shape of the bottom of the oxidation reactor vessel, and all openings in them are equidistant from each other and from the wall of the oxidation reactor vessel. 7. The method according to claim 1, characterized in that the reduction of the temperature gradient in the oxidation reactor is provided by the circulation of a fully or partially oxidized stream, returning it to the reactor. 8. The method according to claim 7, characterized in that the circulating fully or partially oxidized stream is subjected to cooling. 9. The method according to claim 8, characterized in that the flow rate of the circulating cooled completely or partially oxidized stream provides for the regulation of the temperature gradient in the oxidation reactor. 10. The method according to claim 8, characterized in that the temperature of the circulating cooled completely or partially oxidized stream provides for the regulation of the temperature gradient in the oxidation reactor. 11. The method according to claim 1, characterized in that the reduction of the temperature gradient in the oxidation reactor provides fractional circulation of a fully or partially oxidized stream, taking it from the reactor from one or more zones and returning it in separate streams, but not less than one, to different positions the height of the reactor. 12. The method according to claim 11, characterized in that during fractional circulation, the fully or partially oxidized stream supplied to various positions along the height of the oxidation reactor is subjected to cooling. 13. The method according to p. 12, characterized in that during fractional circulation of the fully or partially oxidized stream supplied to various positions along the height of the oxidation reactor, the temperature gradient along the height of the oxidation reactor is controlled by changing the flow rate of the circulating fully or partially oxidized bitumen supplied to various position on the height of the oxidation reactor. 14. The method according to p. 12, characterized in that during fractional circulation of the fully or partially oxidized stream supplied to various positions along the height of the oxidation reactor, the temperature gradient along the height of the oxidation reactor is controlled by changing the temperature of the circulating fully or partially oxidized bitumen supplied to various position on the height of the oxidation reactor. 15. The method according to claim 1, characterized in that an injector is used as a turbulent mixer. 16. The method according to p. 15, characterized in that as the working fluid in the injector using an unoxidized stream at a flow rate of an oxidized stream less than an unoxidized stream. 17. The method according to p. 15, characterized in that as the working fluid in the injector, an oxidized stream is used at a flow rate of an oxidized stream greater than an unoxidized stream. 18. The method according to claim 1, characterized in that diaphragmed disks are used as a turbulent mixer. 19. The method according to claim 1, characterized in that the exhaust air leaving the oxidation reactor is subjected to the removal of hydrocarbons in the separator by cooling with a circulating black tanning bed and then these gases are disposed of in the afterburner while heating the coolant or catalytic purification of organic impurities is carried out. 20. The method according to claim 1, characterized in that the exhaust air leaving the oxidation reactor is mixed with fresh air before catalytic purification in a ratio of 1: (0.1-0.005). 21. The method according to claim 20, characterized in that the exhaust air leaving the oxidation reactor is subjected to catalytic purification from organic impurities in a plate-catalytic reactor at a temperature of 150-200 ° C. 22. The method according to item 21, characterized in that as a catalyst in a plate-catalytic reactor using platinum or palladium. 23. The method according to claim 20, characterized in that the exhaust air leaving the oxidation reactor is additionally heated in the furnace by burning fuel gas or in the heat exchanger due to the heat of the coolant and is subjected to catalytic purification of organic impurities in a plate-catalytic reactor at a temperature of 250- 350 ° C. 24. The method according to item 23, wherein the catalyst in the plate-catalytic reactor using oxides of copper, chromium, iron, zinc, barium, or a mixture of these oxides. 25. The method according to claim 1, characterized in that tar can be used as feedstock after vacuum distillation of fuel oil, heavy products of the selective separation of hydrocarbons, heavy extracts of the production of mineral oils or mixtures thereof. 26. The method according to claim 1, characterized in that the depth of penetration of the needle in the resulting product is controlled by the residence time of the oxidizable portion of the feed stream in the oxidation reactor. 27. The method according to claim 1, characterized in that the depth of penetration of the needle in the resulting product is controlled by the temperature in the oxidation reactor. 28. The method according to claim 1, characterized in that the depth of penetration of the needle in the resulting product is controlled simultaneously by the residence time of the oxidizable portion of the feed stream in the oxidation reactor and the temperature in the oxidation reactor. 29. The method according to claim 1, characterized in that the depth of penetration of the needle in the resulting product is controlled by the ratio of oxidized and non-oxidized feed streams. 30. The method according to claim 1, characterized in that the resulting product receive road, construction and roofing bitumen. 31. The method according to claim 1, characterized in that the road, construction and roofing bitumens are obtained simultaneously for each type of product in at least three parallel oxidation reactors as the obtained product. 32. The method according to claim 1, characterized in that the heating of one stream of raw materials is performed in heat exchangers due to heat of the heat carrier or in the coil of a tubular furnace with a partial supply of oxygen. 33. The method according to p. 32, characterized in that the heating of the stream supplied to the oxidation of raw materials is carried out in heat exchangers arranged in series: first in the heat exchanger due to the heat of the heat carrier heated in the afterburner due to the utilization of exhaust gases, then in the heat exchanger due to heat of the oxidized product and then in the heat exchanger due to the heat of the circulating irrigation of the oxidation reactor. 34. Installation for producing bitumen, including a tubular furnace with a coil, an oxidation reactor, a pump for supplying raw materials with suction and discharge pipes, a raw material pipe connecting the pump discharge pipe with the inlet of the pipe furnace coil, a pipe connecting the outlet of the pipe furnace coil with the upper part of the reactor oxidation, an air distributor located at the bottom of the reactor, a compressor connected by a pipe to the air distributor, and a pipeline for removing bitumen from the oxidation reactor, excellent In that the installation is equipped with a turbulent mixer of oxidized product and non-oxidized raw materials, a catalytic treatment reactor for exhaust air coming out of the oxidation reactor, connected by pipelines to the outlet fittings of the oxidized product and exhaust gases, respectively, the main part of at least one oxidation reactor is is a reaction space where the oxidizable feed is in contact with oxygen diffusing from the volume of air bubbles to the surface ate phases, and the upper part of the reactor is a separation space in which the bitumen is separated from the air, the oxidation reactor is equipped with a bypass pipe connected on one side to the discharge pipe of the pump for supplying raw materials, and on the other hand, with a turbulent mixer, the oxidation reactor is equipped with an additional a circulation pump connecting the suction pipe to the bottom of the oxidation reactor and the discharge pipe to at least one or more circulation circuits on which x recycle coolers are installed, the outputs of the circulation circuits are connected to the oxidation reactor, the oxidation reactor vessel in the middle part consists of several zones, each of which in the course of the fluid flow has a sequentially diffuser, cylindrical and confuser configuration. 35. The installation according to clause 34, wherein the compressor is additionally connected by a pipe to the inlet of the coil of the tubular furnace or heat exchanger for heating raw materials. 36. The installation according to clause 34, characterized in that the pipeline of raw materials is connected to a heat exchanger that heats the feedstock due to the heat carrier heated in the afterburning furnace by utilizing the exhaust gases, then the pipeline is connected to a heat exchanger, where the heating is carried out due to the heat of the oxidized product , after the pipeline is connected to the heat exchanger, where heating occurs due to the heat of the circulation irrigation of the oxidation reactor. 37. Installation according to clause 34, wherein the number of oxidation reactors corresponds to the number of simultaneously produced grades of one type of bitumen or the number of different types of bitumen. 38. Installation according to clause 34, wherein the diameter of the separation part of the oxidation reactor is greater than or equal to the diameter of the reaction space of the oxidation reactor. 39. Installation according to clause 34, wherein the outlet of the fully or partially oxidized stream to the circulation loop, designed to return the cooled completely or partially oxidized stream to the oxidation reactor, is made in the cylindrical part of the housing above or below the interface with the diffuser and confuser configurations of the housing oxidation reactor. 40. Installation according to clause 34, wherein the input of the circulation circuit into the oxidation reactor is connected to the oxidation reactor at the interface between the diffuser and confuser configurations of the oxidation reactor vessel. 41. The apparatus of claim 39, wherein the input of the circulation loop to the oxidation reactor is connected to the oxidation reactor at the interface between the diffuser and confuser configurations of the oxidation reactor vessel along the axis of the normal section of the vessel. 42. The apparatus of claim 39, wherein the input of the circulation loop to the oxidation reactor is connected to the oxidation reactor at the junction of the diffuser and confuser configurations of the oxidation reactor vessel tangentially to the body. 43. The apparatus of claim 39, wherein the circulation loop input to the oxidation reactor is made in the form of an external annular collector coupled to the oxidation reactor at the interface between the diffuser and confuser configurations of the oxidation reactor vessel. 44. Installation according to item 43, wherein the outer annular collector is connected by tangential nozzles to the body of the oxidation reactor. 45. Installation according to claim 42, characterized in that the tangential nozzles of the outer annular collector are located equidistant or concentrated on one or more sections. 46. The installation according to claim 39, wherein the input of the circulation loop to the oxidation reactor is made in the form of two ring collectors, wherein the external ring collector is interfaced with the body of the oxidation reactor, and the internal ring collector is placed inside the oxidation reactor, and the collectors are located at the interface diffuser and confuser configurations of the oxidation reactor vessel. 47. The installation according to item 46, wherein the pipes of the outer and inner annular collectors tangentially communicate with the interior of the oxidation reactor vessel. 48. Installation according to clause 34, wherein the air distributor has headers coupled to the bubblers. 49. The apparatus of claim 34, wherein the diameter of the holes in the bubbler device d is not less than d = (Ar · µ ² / ρ ² · g) ^1/3 , where µ (Pa · s) and ρ ( kg / m ³ ), respectively, the viscosity and density of the oxidizable flow, g is the acceleration of gravity (9.81 m / s ² ), Ar is the Archimedes criterion. 50. The apparatus of claim 49, wherein the number of holes in the bubbler device N is greater than N = 0.732Q · ρ / (d · µ · (Ar) ^1/2 ), where Q is the air flow in the reactor (m ³ / s). 51. Installation according to clause 34, wherein an injector is used as a turbulent mixer. 52. The apparatus of claim 51, wherein the line for supplying the working fluid to the injector is connected to the bypass pipeline for supplying an oxidized stream at an oxidized stream flow rate less than the oxidized stream, and the line for suctioning the liquid into the injector is connected to the bottom of the reactor oxidation. 53. The apparatus of claim 51, wherein the line for supplying the working fluid to the injector is connected by an oxidized flow pipe to the bottom of the oxidation reactor at a flow rate of an oxidized stream greater than the non-oxidized stream, and the line of suction of the liquid into the injector is connected to the bypass supply pipe of the non-oxidized stream . 54. The apparatus of claim 51, wherein a diaphragm mixer with diaphragmed disks is used as a turbulent mixer. 55. The apparatus of claim 51, wherein the catalytic air purification reactor is a housing in which a stack of plates is mounted on the surface of which a catalyst coating layer is applied. 56. The apparatus of claim 55, wherein the catalytic purification reactor vessel in a normal section has a square, rectangular or round shape. 57. The installation according to item 55, wherein the catalytic purification reactor is a pipeline connected to the top of the oxidation reactor, in which a package of plates is installed, on the surface of which a catalyst coating layer is applied. 58. Installation according to claim 34, characterized in that a separator is installed on the pipeline connecting the top of the oxidation reactor to the catalytic treatment reactor. 59. The apparatus of claim 34, wherein the exhaust gas heater is installed in front of the catalytic treatment reactor. 60. The installation according to p. 59, characterized in that the exhaust gas heater is a firebox or heat exchanger with a coolant. 61. The apparatus of claim 59, wherein the exhaust gas heater is a coil of a convection chamber of a tubular furnace. 62. Installation according to clause 34, wherein an anchor mixer is installed in the lower part of the separation part of the oxidation reactor. 63. Installation according to clause 34, characterized in that in each of the zones of the middle part of the oxidation reactor having a sequentially diffuser, cylindrical and confuser configuration, a mixing device is placed. 64. The apparatus of claim 63, wherein the mixing device is a propeller stirrer. 65. The apparatus of claim 64, wherein the propeller stirrer in the oxidation reactor provides a downward circulation of the oxidizable feed: air system. 66. Installation according to item 65, wherein the propeller stirrer is located in the guide cylinder. 67. Installation according to item 63, wherein the mixing device is a disk mixer.

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