EA043337B1 - METHOD FOR PYROLYSIS OF LIQUID AND GASEOUS HYDROCARBONS AND DEVICE FOR ITS IMPLEMENTATION - Google Patents

Description

The invention relates to the oxidative pyrolysis of hydrocarbon raw materials, in particular gasoline fractions, kerosene, gas oils, ethane, propane, butane, as well as rapid coking, and can be used in the petrochemical industry.

Prior Art

Currently, the petrochemical industry consumes large volumes of pyrolysis products (thermal, oxidative) of petroleum fractions (gasoline, kerosene, gas oil), which are used for the production of plastics, synthetic threads, rubber, etc. At the same time, the greatest demand is for pyrolysis products such as lower olefins and, first of all, ethylene and propylene (from 30 to 45% by weight in pyrolysis products [1, p. 54]. In addition, such pyrolysis by-products are in great demand , as aromatic hydrocarbons (benzene, toluene, xylene, naphthalene - up to 8-15% by weight of pyrolysis products [1, pp. 54-56]. At the same time, there is an acute problem of increasing the depth of processing of oil refineries, up to obtaining as the final product of petroleum coke, one of the most popular forms of which is carbon black.The inventive method and device for its implementation will effectively solve the problem of producing lower olefins and carbon black by oxidative pyrolysis.

The general scheme of thermal pyrolysis is disclosed in the book [1, pp. 95-200]. The raw materials for the pyrolysis process are gaseous (ethane, propane, butane) and liquid (light gasoline and kerosene fractions, gas oils) hydrocarbons. The process consists of the fact that the raw material, heated in the convection part of the furnace, is mixed with superheated water vapor and enters the reaction coil located in the radiant part of the furnace. Due to the heat of the combustion products of the air-fuel mixture supplied to the walls of the coil, the decomposition of raw materials occurs with the formation of various (mainly lighter) products. In this case, the temperature of the reacting stream gradually increases to 1100-1200°C, after which the mixture is quickly cooled to prevent the loss of the most valuable products during secondary reactions. Next, the cooled mixture enters the compression, separation and gas separation units. The target products of this pyrolysis scheme are hydrogen (if hydrocarbon gases are used as raw materials), olefins (primarily ethylene and propylene), as well as aromatic hydrocarbons (primarily homologues of benzene and naphthalene).

However, the thermal pyrolysis process has such disadvantages as high capital costs for the construction of pyrolysis furnaces associated with the need to use high-alloy steels in large volumes, limited furnace power due to problems with hydraulic resistance in the pipes of the coils for heating raw materials, problems of coke formation in the furnace coils and technical difficulties in supplying large amounts of heat to the heated coil pipes.

These disadvantages are absent when using the oxidative pyrolysis process [2, p. 82]. At the same time, the hardware design is significantly simplified, and the oxidative pyrolysis reactor is a small pipe made of ordinary steel, lined on the inside with fireclay bricks [3, p. 121]. Oxidative pyrolysis is carried out in the presence of oxygen, which serves to obtain the required temperature (1400-1600°C) due to the partial combustion of hydrocarbons. Pyrolysis at such temperatures is used, for example, to produce acetylene-containing gases from methane. The apparatus for oxidative pyrolysis has a mixing zone in which methane is mixed with oxygen, a reaction zone and a zone for hardening the reaction gases. The length of the reaction zone is only 150 mm. In its final part, the products meet streams of water sprayed by nozzles (quenching occurs). At the same time, the temperature of the gases drops sharply and chemical processes stop, as a result of which the resulting valuable unsaturated hydrocarbons are preserved, since undesirable secondary reactions completely stop. Hydrocarbon gases, as well as light and heavy oil fractions, can be subjected to oxidative pyrolysis, and not only water, but also various hydrocarbons, molten metals and their salts can be used for hardening.

At the same time, the process of oxidative pyrolysis also has specific disadvantages [4, p. 398], associated with the problem of utilizing large volumes of heat from a mixture of water vapor with products of incomplete combustion of hydrocarbons. For example, when processing 50-60 thousand tons of straight-run gasoline per year as a raw material for the production of ethylene, when quenching with water for an hour, about 15 tons of water vapor with a temperature of about 100 ° C will be formed, the disposal of which represents a significant technical problem if there is no possibility of transferring this excess heat to external consumers. The problem of heat utilization during hardening with hydrocarbons is no less acute.

There is a known method for processing tar sands (RU No. 2456328, IPC C10C 1/04, C10G 1/02, published on March 27, 2012), in which the initial heating of tar sand is carried out at a temperature of 400-500°C in a visbreaking mixer-reactor simultaneously with its effective mixing until a homogeneous consistency is obtained, and after separating the volatile fractions of petroleum products, a product of reduced viscosity is obtained, which is sent to a fast coking reactor, where the flow of the resulting product is dispersed and moved by a gas jet, while the gas is supplied at a speed of 30-40 m/s , and the coking process is carried out in hydrodynamic mode with the creation of a stable gushing layer at atmospheric pressure and a temperature of 600-650°C (gas) for 1-2 s,

- 1 043337 after which the formed coke is removed, and the coke gases are sent to an apparatus with counter swirling flows, where solid particles are separated, and then to a scrubber for separation into condensable and non-condensable components. Carrying out the coking process in a hydrodynamic mode with the creation of a stable gushing layer and the movement of the raw material flow by a gas jet at atmospheric pressure and a temperature of 600-650°C for 1-2 s allows for a rapid process of coke formation and promotes the stable release of the condensable component in the form of gas oils. It has been experimentally established that the given modes during the coking process are the most optimal. Carrying out the above processes ultimately contributes to the maximum coke yield, which is close to the material balance of coke yield during slow coking. At the same time, the technology of the proposed fast coking requires significantly lower capital costs during construction and significantly lower operating costs than when implementing the delayed coking method.

The disadvantage of this method is that it uses the principle of thermal contact coking, which requires a contact coolant (usually coke grains), the use of unstable fluidized bed technology, which may cause problems when changing raw materials, as well as the impossibility of using the resulting coke for the production of electrodes for metallurgical industry and for the production of carbon black, since it can only be used as fuel for boiler houses.

The closest in technical essence and achieved result to the claimed method is a method for processing hydrocarbon raw materials (RU No. 2325426, IPC G10G 9/38, published July 25, 2008), including in the form of heavy oil residues containing fractions boiling at temperatures above 350°C, including the generation of high-temperature coolant by burning fuel in oxygen, preheating of hydrocarbon raw materials above the melting point, but below the coke or tar formation temperature, and simultaneous supply of high-temperature coolant and preheated hydrocarbon raw materials into the reaction zone of the pyrolysis chamber, heating of the hydrocarbon raw materials at a rate equal to (4-5)-105 to temperatures of 700-2500°C, followed by hardening of the reaction products. Characteristic of this method is that the high-temperature coolant contains hydrogen in the concentration range from 30-35% by volume, and after reaching a temperature of 700-2500°C in the reaction zone, quenching components are introduced into the reaction stream in two stages and the reaction mixture is cooled at a speed cooling 1-105-5-105 deg/s to a temperature level of 600-1300°C in the first stage and with a cooling rate of 2-104-4-10 ⁴ deg/s to a temperature of 300-1000°C in the second stage to stop secondary processes. The method makes it possible to reduce the sulfur content in the target products, increase the yield and provide regulation of the fractional composition of the resulting target products.

The disadvantage of this known method is that it is one of the options for implementing the hydrocracking process and is intended to increase the yield of light petroleum products (light liquid fractions) in the process of pyrolysis (cracking) of heavy petroleum residues (fuel oils and gas oils), as well as to purify petroleum products from sulfur for due to the use of hydrogen (an option for hydrotreating sulfur). The hardening processes in this method occur very slowly (within 2-3 s), and are aimed at ensuring secondary processes that occur during hydrocracking. At the same time, to obtain lower olefins and dienes, the duration of the quenching process should not exceed 0.03 s when cooling the pyrogas to a temperature of 540-760°C [1, p. 118]. Thus, this method does not provide the production of olefins. In addition, when using this method, coke formation and the volume of solid carbon particles are significantly reduced, which eliminates the possibility of its use for producing carbon black.

To obtain the maximum depth of oil refining, and, consequently, to obtain the maximum amount of valuable petroleum products, the oil industry uses various equipment when implementing technologies for coking heavy oil residues. The most common method in world practice is delayed coking. The process is carried out as follows [5, p. 310]. Secondary raw materials (heavy oil residues) are heated in tube furnaces to 490-510°C and enter the coke chambers - hollow vertical cylindrical devices with a diameter of 3-7 m and a height of 22-30 m.

The reaction mass is continuously fed into the chamber for 24-36 hours and, thanks to the heat accumulated by it, cokes. After filling the chamber with coke by 70-90%, it is usually removed with a jet of water under high pressure (up to 15 MPa).

The coke enters the crusher, where it is crushed into pieces no larger than 150 mm, after which it is fed by an elevator to a screen, where it is divided into fractions of 150-25, 25-6 and 6-0.5 mm.

The chamber from which the coke is unloaded is heated with hot water vapor and vapors from the operating coke chambers, and again filled with coking mass.

Delayed coking produces the bulk of low-ash petroleum coke, which is used in the production of aluminum and for the smelting of high-quality steel. However

- 2 043337 the process of delayed coking of oil residues in such installations is accompanied by significant foaming, as a result of which the yield of volatile substances increases and the mechanical strength of coke decreases. In addition, foaming of coking raw materials leads to the need to prematurely stop the supply of raw materials, and therefore, 35-40% of the volume of coking chambers is not used and the productivity of coke oven batteries is sharply reduced [6, p. 167]. In addition, delayed cokers require significant capital costs and significant depreciation charges, since the shut-off valves on the cokers require annual replacement, as well as due to the short overhaul interval (an average of 9 months). In addition, most of the coke produced by delayed coking can only be used as fuel for boiler houses, i.e. has a low market value. Meanwhile, it is impossible to obtain such a commercially profitable product as carbon black from coke using slow coking technology.

A known reactor is used for processing flammable carbon and/or carbon-containing products by pyrolysis (RU No. 2544669, IPC C10B 49/02, C10J 3/72, F23G 5/027, C10B 53/00, C10B 57/00, B09B 3/00, published March 20, 2015). The reactor contains a torus for processing flammable carbon and/or hydrocarbon-containing products, including a sealed working chamber with working zones arranged in a technological sequence: unloading solid processing residues with an unloading window, supplying an oxygen-containing agent, heating the oxygen-containing agent, combustion, coking and pyrolysis, heating products processing, selection of a vapor-gas mixture, with at least one selection channel, and a loading area for processed products with a gateway. The working chamber contains a zone for supplying wet small particles of solid fuel waste and their pyrolysis and coking, combined with zones for supplying and heating an oxygen-containing agent, while its supply channel is connected to a dosing hopper for wet small particles of solid fuel waste with the possibility of forming them in the corresponding zone inside a fluidized flow reactor.

The disadvantages of the known reactor for processing flammable carbon and/or carbon-containing products include the impossibility of obtaining lower olefins such as ethylene, propylene and butylene in any noticeable volume as pyrolysis products, since they are obtained from the pyrolysis of light and medium fractions of hydrocarbons (for example gasoline and kerosene) at a temperature of 750900°C in a fraction of a second and then undergo sharp cooling (quenching) for example with water or other liquids also in a fraction of a second. In the device described, such processes are not provided for and are impossible. In the described device, the pyrolysis process is aimed at obtaining liquid pyrolysis products by recycling carbon-containing residues.

A reactor for processing hydrocarbon raw materials is known, taken as the closest analogue (RU No. 2290991, IPC B01J 19/2, G01G 7/06, publ. 01/10/2007), which refers to devices for processing bottoms, tars, bitumen, fuel oil, etc. The reactor for processing hydrocarbon raw materials includes an ignition unit for the gas mixture and a prefabricated cooled housing, which consists of a working fluid formation chamber, a pyrolysis chamber with a feed unit for the processed raw materials, and quenching chambers. Connections for supplying and discharging reagents are attached to the body. The reactor additionally contains a hot gas generator, the output of which is connected to the input of the working fluid generation chamber. The hot gas generator has an internal combustion chamber, the walls of which are coaxial to the body of the hot gas generator. The combustion chamber communicates with the gas mixture ignition unit and is equipped with a combustion initiating gas supply pipe. A manifold with radial holes is installed in the inlet part of the working fluid generation chamber, which communicates with the fuel supply pipe. Between the working fluid generation chamber and the pyrolysis chamber there is a feed unit for the processed raw materials, made in the form of radial nozzles mounted on the reactor vessel. Between the pyrolysis chamber and the quenching chamber there is a hydrogen or hydrogen-containing gas supply unit made in the form of radial nozzles mounted on the reactor vessel. The invention improves the quality of the resulting product and significantly increases the turnaround time.

The disadvantage of the known device is that it is a reactor for implementing the hydrocracking process, designed to increase the yield of light petroleum products (light liquid fractions) in the process of pyrolysis (cracking) of heavy oil residues (fuel oils and gas oils). However, when operating such a device, coke formation and the volume of solid carbon particles are significantly reduced, which precludes its use for the production of carbon black.

Disclosure of the Invention

The main objective of the claimed invention is to create an effective method for the oxidative pyrolysis of hydrocarbon feedstocks, in particular gasoline fractions, kerosene, gas oils, ethane, propane, butane and a device for its implementation in order to obtain olefins, aromatic hydrocarbons, hydrogen and carbon black, in which the utilization of heavy oil residues, and it is possible to simultaneously obtain lower olefins, carbon black and selectively isolate aromatic hydrocarbons using oxidative pyrolysis.

The technical result consists in the utilization of heavy oil residues by rapid coking with high economic efficiency and environmental friendliness to produce high quality coke, in oxidative pyrolysis for the production of lower olefins by quenching pyrolysis products with heavy oil residues using the energy of incomplete combustion, in the production as a result of pyrolysis of aromatic compounds such as benzene, toluene, xylene and naphthalene by quenching and cooling with liquid hydrocarbons and selective separation of aromatic hydrocarbons without the construction and use of separate special installations.

At the same time, the use of the proposed method and device provides a high economic effect, since it allows one to replace several economically expensive installations with one economical installation.

The problem is solved by the fact that in the known method of oxidative pyrolysis, which includes the generation of a high-temperature coolant by incomplete combustion (oxidative pyrolysis) of preheated hydrocarbon raw materials in oxygen or in a mixture of oxygen and water vapor, also preheated, sharp cooling (quenching) of the pyrolysis products liquid hydrocarbons are carried out in two stages, light and medium oil fractions (gasoline, kerosene, gas oils) are used as pyrolysis raw materials in the oxidative pyrolysis unit, and quenching of pyrolysis products is carried out with heavy oil residues (fuel oil, gas oil, cracking residue), by means of their finely dispersed spraying into the flow of combustion products, while reducing the temperature of the resulting steam-gas mixture to the temperature of the equilibrium value of the combustion products within the range of no less than 450 and no more than 650 ° C in a short period of time, the resulting steam-gas mixture is sent to the channel of the coking reactor with the formation of coke particles and evaporation from them surface of the gas oil fractions and their partial cracking, from where the steam/dust/gas flow is fed into a separation unit, where the coke is separated, then the coke is fed for further processing, and the steam-gas mixture, purified from coke, is subjected to the second stage of cooling to a temperature of at least 250°C with liquid hydrocarbons , for example, oil, fuel oil, gas oil, by finely dispersing them into the pyrogas flow, and then the cooled vapor-gas mixture is sent to the fractionation unit.

Gasoline fractions, kerosene, gas oil, ethane, propane, butane can be selected as hydrocarbon raw materials.

In the fractionation unit, it is possible to obtain light, medium and heavy oil fractions with dissolved aromatic hydrocarbons (pyrolysis products) such as benzene, toluene, xylene and naphthalene, and non-condensed gases containing olefins (ethylene, propylene and butylenes) from the fractionation unit can be transferred for further processing.

It is recommended to keep the water vapor content in the steam-oxygen mixture within the range from 0 to 50% by weight.

It is rational to ensure that the content of the composition of the steam-oxygen mixture is in the range from 15 to 25% of the mass of the raw material subjected to pyrolysis.

Hydrocarbon gases (methane, ethane, propane and butane) can be used as pyrolysis raw materials in order to obtain significant volumes of hydrogen in the pyrolysis products (up to 40-50% by volume).

It is recommended to cool the vapor-gas mixture at the first stage in a time of 0.005-0.03 s.

As a unit for fractionating the vapor-gas-liquid mixture after the second cooling stage, a cyclone-type installation can be used, made according to the method of distillation of hydrocarbon raw materials according to RF patent No. 2301250.

It is recommended that the dimensions of the coking reactor channel be determined in accordance with the productivity of the oxidative pyrolysis unit for the resulting pyrolysis gas and ensure that the residence time of coke particles in the coking reactor channel is at least 2 s.

The separation of coke particles from pyrogas in the separation unit can be carried out in an electric precipitator through deposition on electrodes and agglomeration of fine coke particles by electrofiltration.

The coke obtained by the claimed method corresponds in its characteristics to carbon black. Coke is separated from the stream, for example, by depositing it on an electric precipitator, where it agglomerates, and the resulting agglomerates are shaken off into the gas stream and removed from the gas stream, for example, by a gas-dynamic cyclone.

When using hydrocarbon gases as a raw material for pyrolysis, a significant amount of hydrogen is present in the pyrolysis products, up to 40-50% of the volume, which can be used for hydrotreating, hydrocracking, reforming, etc. processes.

A significant difference from the known methods is that quenching at the first stage is carried out with heavy oil fractions, while reducing the temperature of the resulting vapor-gas mixture to the equilibrium value of the temperature of the combustion products in a short period of time, for example, to a temperature not higher than 650°C, since at more At high temperatures, reverse reactions occur, and the yield of olefins decreases sharply, and, for example, temperatures are not lower than 450°C, since at lower temperatures the time required for the evaporation of gas oils from coke particles increases sharply.

What is also new and significant is that the cooling of the pyrogas purified from coke particles is carried out by a wide fraction of liquid hydrocarbons (for example, oil) to the end boiling point, not lower than the boiling point of aromatic hydrocarbons, i.e. lying in the range from 250°C and above (the naphthalene fraction is in the range of 210-240°C in terms of boiling points, and boiling

- 4 043337 benzene, toluene and xylene occurs at a significantly lower temperature (up to 150°C), which makes it possible to utilize excess heat of oxidative pyrolysis by fractionating the resulting mixture to produce oil fractions such as naphtha, kerosene, diesel and fuel oil fractions with aromatics dissolved in them hydrocarbons. Fractionation of such a vapor-liquid flow can occur using any fractionation technology in which single evaporation and multiple stage-by-stage cooling are carried out (for example, according to RF Patent No. 2301250 with a cyclone-type installation). This combined solution allows you to save on the construction of a separate fractionation unit, in which up to 3-3.5% of the mass of the processed raw material is spent on distillation of fractions as working fuel for heating the raw material, and allows you to immediately obtain hydrocarbon fractions with aromatic hydrocarbons dissolved in them for their further extraction.

The problem is also solved by the fact that in the known device for carrying out the pyrolysis of liquid and gaseous hydrocarbons by a method containing a mixing chamber of the steam-oxygen mixture and raw materials, a pyrolysis chamber and a coking reactor, a device for heating hydrocarbon raw materials, a device for heating the steam-oxygen mixture, connected to the mixing chamber of the steam-oxygen mixture are additionally introduced mixtures and raw materials, a coking reactor and a separation unit connected to the coking reactor, the pyrolysis chamber is made in the form of a fire-barrier grid with longitudinal channels in which combustion reactions occur, the entrance to the coking reactor is a quenching zone and is equipped with a device for supplying coolant to the pyrogas flow, and the separation unit is connected to the fractionation unit by a channel equipped with an additional coolant supply device.

It is rational to design coolant supply devices in the form of a belt of spray nozzles, designed to supply coolant under pressure.

The separation unit for separating coke particles from pyrogas may contain at least two electric precipitators, configured to be turned on periodically as agglomerated carbon black accumulates on the electrodes of the operating electrostatic precipitator.

It is recommended that electric precipitators be designed with the ability to switch the pyrogas flow to an electric precipitator with clean electrodes, shake them, and transfer carbon with water vapor or inert gas to the cooling unit.

The fire barrier grid can be made in the form of longitudinal channels, ensuring the residence time of the reagents in the channel is no more than 0.003-0.01 s, with a speed of movement of the reagents exceeding the speed of flame propagation during combustion of the reagents.

A significant difference from the prototype in the claimed device is the possibility of converting fine droplets of heavy residue into coke particles by cracking and evaporation of gas oil fractions from their surface.

The claimed method for the pyrolysis of liquid and gaseous hydrocarbons and the production of carbon black and the device for its implementation are not known from the prior art; therefore, the claimed solutions satisfy the condition of patentability of the invention: novelty.

An analysis of the level of technology for compliance of the claimed solutions with the patentability of the invention, the inventive step, showed the following.

In the presented method of oxidative pyrolysis of hydrocarbon raw materials and a device operating on its basis, in contrast to those known for the simultaneous production of lower olefins and carbon black by recycling heavy oil residues, quenching of pyrolysis gases is carried out at the first stage with heavy oil residues to the temperature of the equilibrium value of the combustion products, for example, not higher than 650 and not lower than 450°C, which makes it possible to obtain lower olefins and not lose them, to carry out rapid coking of fine particles of atomized heavy oil residues and heavy pyrolysis resins, since the flow temperature is more than 450°C, and below this temperature coking processes and pyrolysis proceed too slowly.

It is recommended to maintain the flow temperature above 600°C (ie between 600-650°C) to achieve rapid coking in the shortest possible period of time.

The device is equipped with a coking reactor, the diameter and length of which ensure that coking particles remain in the evaporation zone for at least 2 s, which makes it possible to obtain coke in the form of fine carbon black. The steam-dust-gas flow from the coking reactor enters the separation unit, where coke is separated using one of the known methods (for example, using electric precipitators), which is supplied for further processing, and the steam-gas mixture, cleared of coke, is subjected to a second cooling stage by injecting a wide fractions of liquid hydrocarbons (for example, oil, gas condensate, gas oils) until the end boiling point is not lower than the boiling point of aromatic hydrocarbons (i.e., not lower than 250°C, for example, up to a temperature of 350°C), which allows the pyrocondensate obtained as a result of pyrolysis to be distributed into petroleum feedstock, which has already been subjected to a single evaporation, and therefore is prepared for fractional separation (into gasoline, kerosene, gas oils and fuel oil).

Aromatic compounds such as benzene, toluene, xylene and naphthalene obtained during pyrolysis during quenching and cooling with liquid hydrocarbons are dissolved in hydrocarbon fractions corresponding to their boiling point, which ensures selective

- 5 043337 separation of aromatic hydrocarbons without the construction and use of separate special installations for separating pyrocondensate into components, which helps achieve the stated technical result.

The method and device are so interconnected that they form a single inventive concept, since one of them is intended to implement the other, the set of features of each affects the achieved technical result, therefore this invention satisfies the requirement of unity.

Brief description of drawing figures

The method of pyrolysis of liquid and gaseous hydrocarbons and the device for its implementation are illustrated in the drawings, where in FIG. 1 shows a diagram of an installation that implements the proposed pyrolysis method;

in fig. Figure 2 shows a diagram of the separation block (item 8 in Fig. 1);

in fig. Figure 3 shows a diagram of the fractionation unit (according to the method of distillation of hydrocarbon raw materials, patent RU No. 2301250).

Examples of Preferred Embodiments of the Invention

The device (Fig. 1) contains a furnace 1 for heating hydrocarbon feedstock to 500-600°C, a furnace 2 for heating the oxidizer to 200-400°C (for example, oxygen from 10 to 20 wt.% of the feedstock or a mixture of oxygen from 10 to 20 wt.% of the raw material and up to 20% water), a mixing chamber 3 of the oxidizer and raw materials with an ignition zone 4 at the exit from the mixing chamber, a fire-barrier grille 5, in the channels of which combustion reactions occur, a belt of spray nozzles 6, through which it is supplied under pressure quenching liquid (any petroleum products and, above all, heavy residues - fuel oil, gas oil, cracking residue), coking reactor 7, which is a hollow pipe, separation unit 8 for separating coke from the pyrogas flow, channel 9 for supplying the vapor-gas mixture to the fractionation unit 11, belt nozzles 10 for injecting coolant in the form of a wide fraction of hydrocarbons (for example, oil, gas condensate, gas oil or diesel fraction) for additional cooling of the vapor-gas-liquid mixture at the second stage of pyrogas cooling.

The method using the device is implemented as follows.

The pyrolysis raw material is fed by a pump (not shown in the drawings) into the heating furnace 1 (Fig. 1), where it is heated, for example, to 500-600°C and then fed into the mixing chamber 3 of the steam-oxygen mixture and raw materials. Oxygen from an oxygen production unit (for example, from a membrane air separation unit, not shown in the drawing) is supplied under pressure to furnace 2 and heated, for example, to 300-400°C. Water steam is supplied separately at a temperature of 100°C. At the exit from the mixing chamber 3 in the ignition zone 4 there is a constant source of flame from any type of ignition device. The ignited mixture enters the channels of the fire-barrier grille 5 with a thickness of, for example, 100 mm and with channel diameters of, for example, 8-12 mm. The shape of the channels can be cylindrical or conical, but it is important that the residence time of the reagents in the channel approximately corresponds to the rate of chemical reactions of oxidative pyrolysis, determined experimentally and equal to approximately 0.003-0.01 s. In this case, the speed of movement of the reagents in the channel cannot be lower than 30 m/s, the speed of flame propagation, so that combustion reactions do not move into mixing chamber 3. Knowing the total consumption of raw materials, it is possible to calculate the dimensions of the fire barrier grid and the number of channels based on the selected channel diameter. For a rectangular channel, the channel diameter is usually taken to be in the range of 8-12 mm, and for a conical channel up to 16 mm at the wide end. Pyrolysis reactions occur in the channels of the fire-barrier grid 5, and the hot grid itself serves as a stabilizer for combustion processes in conditions of a lack of oxidizer. At the exit from the grid 5, a quenching liquid (for example, fuel oil) is injected into the flow through the belt of nozzles 6 to sharply reduce the flow temperature to 600-650°C. The resulting vapor-gas mixture enters the coking reactor 7 and moves to the separation unit 8, in which the resulting fine coke particles are separated from the stream and sent for cooling and further processing. The vapor-gas mixture cleared of coke enters channel 9, where a coolant (for example, oil) is injected into the flow through a belt of nozzles 10 and reduces the temperature of the resulting vapor-liquid mixture to, for example, 350°C. The resulting vapor-liquid mixture is sent to fractionation unit 11.

The diagram of the separation block (item 8 in Fig. 1) is shown in Fig. 2. The flow of pyrolysis gases with coke particles enters one of two electric precipitators 12. Meco-dispersed coke particles settle on electrodes 13 and form agglomerates, and the pyrolysis gas purified from coke is sent to the fractionation unit (item 11 in Fig. 1). As soon as a sufficient volume of coke has accumulated on the electrodes 13, the flow of pyro-gas with coke particles is directed to the second electrostatic precipitator 12, and the stream is purified from coke through the second electrostatic precipitator. And a flow of water vapor 14 (or inert gas) is directed into the first electrostatic precipitator 12 while simultaneously shaking off the deposited coke from the electrodes. The flow of water vapor picks up pieces of agglomerated coke, partially cools it, and the two-phase mixture of steam and coke particles 15 enters the cyclone separator 16. From the cyclone separator 16, the water vapor 17 cleared of coke is sent again to purge the electric precipitator 12, and the coke from the cyclone 16 goes to post-cooling and further processing as carbon black.

- 6 043337

In fig. Figure 3 shows a diagram of the fractionation unit according to the method of distillation of hydrocarbon raw materials according to patent RU No. 2301250. The diagram shows 5 cyclone separators Ts1-Ts5 (19, 22, 25, 28, 31) for separating vapor-liquid mixtures and 4 air cooling units AVO1-AVO4 (21, 24, 27, 30) for partial condensation of hydrocarbon vapors. If oil is used to cool the pyrolysis gases from the outputs of 18 electric precipitators 12 (Fig. 2) to a temperature of 360°C, and any liquid hydrocarbons were subjected to pyrolysis, then the fractionation unit (Fig. 3) operates as follows. The vapor-liquid mixture with a temperature of 360°C enters the first cyclone separator Ts1 (19). From cyclone Ts1 (19), the condensed phase (liquid), which is hydrocarbons with a boiling point above 360°C, flows down the walls of cyclone Ts1 (19) under the influence of gravity and enters, after cooling, through outlet 20 into the commercial stock (fuel oil fraction). A mixture of vapors with boiling points below 360°C is supplied from cyclone Ts1 (19) to the air cooling unit ABO1 (21), where condensation of hydrocarbons with boiling points of 240-360°C occurs. From AVO1 (21), the vapor-liquid mixture enters cyclone Ts2 (22), where, after separation of the vapor and condensed phases, a liquid with boiling points of 240-360 ° C (diesel fuel component) after cooling is supplied through exit 23 to the warehouse (not shown in the drawings) , and a mixture of vapors with boiling points below 240°C enters AVO2 (24). In ABO2 (24), condensation of hydrocarbons with boiling points of 200-240°C occurs, and the resulting vapor-liquid mixture enters cyclone Ts3 (25), where, after separation of the vapor and condensed phases, liquid with boiling points of 200-240°C (diesel fuel component with naphthalene dissolved in it) after cooling through the outlet (26) it enters the naphthalene extraction unit (not shown in the drawings), from where the fraction purified from naphthalene is sent for mixing with the 240-360°C fraction (to produce diesel fuel), and the mixture of vapors with boiling temperatures below 200°C enters ABO3 (27). In ABO3 (27), condensation of hydrocarbons with boiling points of 150-200°C occurs, and the resulting vapor-liquid mixture enters cyclone Ts4 (28), where, after separation of the vapor and condensed phases, liquid with boiling points of 150-200°C (gasoline component) enters through the outlet (29) to the warehouse, and the mixture of vapors with boiling points below 150°C enters AVO4 (30). In ABO4 (30), condensation of hydrocarbons with boiling points below 150°C occurs, and the resulting vapor-liquid mixture enters the cyclone Ts5 (31), where, after separation of the gas and condensed phases, a liquid with boiling points below 150°C (a component of gasoline with dissolved in it BTK - a mixture of benzene, toluene and xylene) after cooling is supplied through output 32 to the BTK extraction unit 9 (not shown in the drawings), from where the fraction purified from BTK is sent for mixing with the 150-200°C fraction (to produce gasoline) and to the warehouse . Gases purified from the condensed phase, containing from 30 to 50% olefins, from the Ts5 cyclone are supplied for further processing through outlet 33.

Examples of concrete implementation

Example 1.

The proposed method of oxidative pyrolysis of hydrocarbon feedstock was implemented in a pilot oxidative pyrolysis plant for processing 68 kg per hour of straight-run gasoline (boiling point -180°C). The raw material was heated to 500°C.

A mixture of 11% (of raw material consumption) oxygen heated to 300°C and 8% water vapor heated to 100°C was used as an oxidizing agent. The shape of the channels of the fire-barrier grid was taken to be square with a side of 8 mm and a wall thickness of 3 mm. The flow rate of combustion products was taken to be 50 m/s with a reaction time of oxidative pyrolysis of 0.003 s and a grate channel length of 150 mm. A total of 16 square-shaped grating channels were made with four channels on each side of the grating.

The calculated adiabatic temperature of the reaction products was approximately 1100°C, and the real one, taking into account heat loss, was about 950°C. Fuel oil was used as a quenching liquid. According to calculations, for quenching (cooling) to a temperature of 600-650°C, 1.92 kg of fuel oil was taken per 1 kg of raw material. For quenching, we used fuel oil from light oil with a yield of light oil products of about 71%, therefore, the calculated yield of coke from such fuel oil was about 15%, i.e. about 19.6 kg per hour. The temperature in the coking reactor was maintained in the range from 660°C at the beginning of the reactor to 615°C at the end of the coking reactor. The actual coke yield was 17.8-18.3 kg per hour. A modified electric precipitator for purifying gases from welding production was used as an electric precipitator for sedimentation of coke particles for the model installation.

The average density of pyrogas at 650°C was 0.82 kg/m ³ , and the density of the vapor phase at this temperature was about 6 kg/m ³ .

The calculated mass fraction of pyrogas was 38.5%, and the mass fraction of the vapor phase was 61.5%. Consequently, the volumetric flow rate of the vapor-gas mixture in the coking channel was 112.5 m ³ /h, or 0.03125 m ³ /s.

The diameter of the coking reactor was taken to be 0.2 m, the flow speed was 1 m/s, and the length of the coking reactor channel was 2.5 m, therefore the residence time of the particles in the coking reactor was at least 2 s.

After cleaning from coke, the steam-gas mixture entering fractionation with a mass flow rate of 0.0546 kg/s was cooled with oil to 350°C. Cooling was carried out with oil with an average yield of light fractions of 71%, with a flow rate of about 0.03 kg/s.

As a result, the following pyrolysis products were obtained*:

* Selection of pyrolysis gases for analysis was carried out at the outlet of the fractionation unit. The values for BTX and naphthalene in pyrolysis products are obtained from the difference between these pyrolysis products dissolved in the corresponding fractions of the coolant (oil) and the values for BTX and naphthalene in the original oil. Data on product yields were obtained using a chromatograph.

Example 2.

Model combined oxidative pyrolysis plant for processing 77 kg per hour of atmospheric gas oil (boiling point 180-330°C). The raw material was heated to 500°C.

11% oxygen (heated to 300°C) and 8% water vapor (heated to 100°C) from the raw material consumption were used as an oxidizer. The shape of the channels of the fire-barrier grid was taken to be square with a side of 8 mm and a wall thickness of 3 mm. The calculated flow rate of combustion products was taken to be 60 m/s, the reaction rate of oxidative pyrolysis was 0.003 s, and the length of the grate channels was 150 mm. A total of 16 grid channels were made in a square shape with four channels on each side of the grid. The calculated adiabatic temperature of the reaction products was approximately 1240°C, and the real one, taking into account heat loss, was about 980°C. Fuel oil was used as a quenching liquid. According to calculations, for quenching (cooling) to a temperature of 600-650°C, 2.0 kg of fuel oil was taken per 1 kg of raw materials. For quenching, we used fuel oil from light oil with a yield of light oil products of about 71%, therefore, the calculated yield of coke from such fuel oil was about 15%, i.e. about 23.1 kg per hour. The temperature in the coking reactor was about 650°C at the beginning of the reactor and 625°C at the end of the coking reactor. The actual coke yield was 28.4-29.5 kg per hour. It is obvious that heavy pyrolysis resins were also subjected to coking. A modified electric precipitator for purifying gases from welding production was used as an electric precipitator for sedimentation of coke particles for the model installation.

The total mass flow rate at the inlet to the coking reactor was 246.4 kg/h, of which the mass flow rate of the vapor-gas mixture was:

246.4-29.0 = 217.4 kg/h.

The average density of pyrogas at 650°C turned out to be 0.82 kg/m ³ , and the density of the vapor phase at this temperature was about 6 kg/m ³ .

The calculated mass fraction of pyrogas was 38.0%, and the mass fraction of the vapor phase was 62.0%. The diameter of the coking reactor was taken to be 0.2 m, the flow speed was about 1 m/s, and the length of the coking reactor channel was 2.5 m, therefore, the residence time of the particles in the coking reactor was at least 2 s.

After cleaning from coke, the vapor-gas mixture entering fractionation with a mass flow rate of 0.0603 kg/s was cooled with vacuum gas oil to 350°C with a flow rate of about 0.033 kg/s.

As a result, the following pyrolysis products were obtained*:

- 8 043337 * Selection of pyrolysis gases for analysis was carried out at the outlet of the fractionation unit. The values for BTX and naphthalene in the pyrolysis products are obtained from the difference between these pyrolysis products dissolved in the corresponding fractions of the coolant (gas oil) and the values for BTX and naphthalene in the original gas oil. At the outlet of the separation unit, a mixture of coolant and pyrocondensate was obtained, which also contained gasoline fractions with boiling points below 200°C. Data on product yields were obtained using a chromatograph.

Example 3.

Using the same model combined oxidative pyrolysis unit, oxidative pyrolysis of methane gas was carried out to produce hydrogen. Ethane consumption was 19 kg per hour. Ethane was heated to 500°C.

10% oxygen (heated to 300°C) and 10% water vapor (heated to 100°C) from the raw material consumption were used as an oxidizer. The shape of the channels of the fire-barrier grille was taken to be square with a side of 8 mm and a wall thickness of 3 mm. The calculated flow rate of combustion products was taken to be 60 m/s, the reaction rate of oxidative pyrolysis was 0.003 s, and the length of the grate channels was 150 mm. A total of 4 channels of a square-shaped lattice were made with the number of channels being 2 on each side of the lattice. The calculated adiabatic temperature of the reaction products was approximately 1200°C (and the real one, taking into account heat loss, was about 1050°C).

Fuel oil was used as a quenching liquid. According to calculations, for quenching (cooling) to a temperature of 600-650°C, 2.2 kg of fuel oil was taken per 1 kg of raw material. For quenching, fuel oil from light oil was used with a yield of light oil products of about 71%, therefore, the calculated yield of coke from such fuel oil was about 15%, i.e. about 6.3 kg per hour. The temperature in the coking reactor was maintained at 660°C at the beginning of the reactor and 635°C at the end of the coking reactor. The actual coke yield was 6.8-7.2 kg per hour. (A modified electric precipitator for purifying gases from welding production was used as an electric precipitator for sedimentation of coke particles for the model installation).

The average density of pyrogas at 650°C turned out to be 0.2 kg/m ³ , and the density of the vapor phase at this temperature was about 6 kg/m ³ .

The calculated mass fraction of pyrogas was 31.0%, and the mass fraction of the vapor phase was 69.0%. The diameter of the coking reactor was taken to be 0.2 m, the flow speed was 0.9 m/s, and the length of the coking reactor channel was 2.5 m, therefore, the residence time of the particles in the coking reactor was at least 2 s.

As a result, the following pyrolysis products were obtained*:

Name product Yield in % (w) of reaction products n ₂ 4.1 CH ₄ 6.5 C ₂ H ₆ 2.4 from ₂ to ₄ 47.0 C ₃ H ₆ 0.5 C ₃ H ₈ 0.0 C ₄ H ₆ 0.2 C ₄ H ₈ 0.0 BTK 0 naphthalene 0

* Selection of pyrolysis gases for analysis was carried out at the outlet of the fractionation unit. Data on product yields were obtained on a chromatograph.

The volume of hydrogen produced was no less than 50% of the volume of pyrogas. In addition, as a result of coking fuel oil, the following were obtained (in wt.% of the original fuel oil):

coking gasoline - 8%;

diesel fractions (boiling points 180-330°C) - 17%;

distillates with boiling points above 330°C - 51%;

carbon black - 16.5%.

The claimed invention contributes to the creation of an effective method for the oxidative pyrolysis of hydrocarbon raw materials, in particular gasoline fractions, kerosene, gas oils, ethane, propane, butane, and a plant for its implementation in order to produce olefins, aromatic hydrocarbons, hydrogen and carbon black.

Bibliography

1. Mukhina T.N., Barabanov N.L., Menshikov V.A., Avrekh G.L. Pyrolysis of hydrocarbon raw materials. M.: Chemistry, 1987, pp. 54-56, 118, 95-200.

2. Lebedev N.N. Chemistry and technology of basic organic and petrochemical synthesis, M.: Khimiya, 1988, P. 82.

3. Reichsfeld V.O. Reaction equipment and plant machines, Leningrad: Khimiya, 1985, P. 121.

4. Miller S.A. Acetylene, its properties, production and use. Translation from English, Leningrad,

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Chemistry, 1969, p. 398.

5. Proskuryakov V.A. Chemistry of oil and gas, St. Petersburg: Chemistry, 1995, P. 310.

6. Merkin A.P. Fragile miracle, M.: Khimiya, 1983, P. 167.

Claims (19)

1. A method of oxidative pyrolysis of liquid and gaseous hydrocarbons, including heating hydrocarbon raw materials, heating a steam-oxygen mixture, burning hydrocarbon raw materials in vapors of a steam-oxygen mixture in a special reactor, sharp cooling of the resulting products of incomplete combustion of hydrocarbon raw materials, characterized in that sharp cooling of the products of incomplete combustion The combustion of hydrocarbon raw materials is carried out in two stages, where at the first stage heavy oil residues are finely dispersed into the flow of incomplete combustion products, while the temperature of the resulting vapor-gas mixture is reduced to the temperature of the equilibrium value of the combustion products in a short period of time, and the resulting vapor-gas mixture is directed into the channel of the coking reactor and further along the channel of the coking reactor with the formation of coke particles and evaporation of gas oil fractions from their surface and partial cracking, the resulting steam/dust/gas flow is transferred to a separation unit, the coke is separated in it to produce a pyrogas stream, the coke is transported for further processing, and the resulting The pyrogas stream is subjected to the second stage of cooling to a temperature of at least 250°C with liquid hydrocarbons by finely spraying them into the pyrogas stream, and then the resulting cooled vapor-gas mixture is sent to the fractionation unit. 2. The method of oxidative pyrolysis according to claim 1, characterized in that gasoline fractions, kerosene, gas oil, ethane, propane, butane are selected as hydrocarbon raw materials. 3. The method of oxidative pyrolysis according to claim 1, characterized in that in the fractionation unit light, medium and heavy oil fractions are obtained with such aromatic pyrolysis products as benzene, toluene, xylene and naphthalene dissolved in them, and non-condensed gases containing olefins, ethylene, propylene and butylenes from the fractionation unit are transferred for further processing. 4. The method of oxidative pyrolysis according to claim 1, characterized in that the content of water vapor in the steam-oxygen mixture is kept in the range from 0 to 50 wt.%. 5. The method of oxidative pyrolysis according to claim 1, characterized in that the composition of the steam-oxygen mixture is ensured in the range from 15 to 25% by weight of the hydrocarbon feedstock subjected to pyrolysis. 6. The method of oxidative pyrolysis according to claim 1, characterized in that hydrocarbon gases methane, ethane, propane and butane are used as gaseous pyrolysis raw materials, ensuring the production of hydrogen in the pyrolysis products up to 40-50%. 7. The method of oxidative pyrolysis according to claim 1, characterized in that a cyclone-type installation is used as a fractionation unit for the vapor-gas-liquid mixture after the second cooling stage. 8. The method of oxidative pyrolysis according to claim 1, characterized in that the dimensions of the coking reactor channel are determined in accordance with the performance of the pyrolysis device for the resulting pyrolysis gas and provide a residence time of coke particles in the coking reactor channel of at least 2 s. 9. The pyrolysis method according to claim 1, characterized in that the separation of coke particles from the steam/dust/gas flow in the separation unit is carried out in an electric precipitator through deposition on electrodes and agglomeration of fine coke particles by electrofiltration. 10. The method of oxidative pyrolysis according to claim 1, characterized in that the cooling of the vapor-gas mixture at the first stage is carried out within 0.005-0.03 s. 11. The method of oxidative pyrolysis according to claim 1, characterized in that the temperature of the equilibrium value of the combustion products is selected within the range of not less than 450 and not more than 650°C. 12. The method of oxidative pyrolysis according to claim 1, characterized in that at the first stage, finely dispersed heavy oil residues in the form of fuel oil or gas oil, or cracking residues are carried out. 13. The method of oxidative pyrolysis according to claim 1, characterized in that the steam-gas mixture, cleared of coke, is subjected to a second stage of cooling to a temperature of at least 250°C with liquid hydrocarbons, in the form of oil or fuel oil, or gas oil. 14. A device for carrying out the oxidative pyrolysis of liquid and gaseous hydrocarbons by the method according to claim 1, containing a mixing chamber of the steam-oxygen mixture and raw materials, a pyrolysis chamber and a coking reactor, characterized in that it additionally contains a device for heating hydrocarbon raw materials, a device for heating the steam-oxygen mixture, connected to a mixing chamber of the steam-oxygen mixture and raw materials, a coking reactor and a separation unit connected to the coking reactor, the pyrolysis chamber is made in the form of a fire-barrier grid with longitudinal channels in which combustion reactions occur, the entrance to the coking reactor is a hardening zone and is equipped with - 10 043337 by a swarm of coolant supply into the vapor-gas mixture flow, and the separation block is connected to the fractionation block by a channel equipped with an additional coolant supply device. 15. A device for oxidative pyrolysis according to claim 14, characterized in that the coolant supply devices are made in the form of a belt of spray nozzles, providing the ability to supply coolant under pressure. 16. A device for oxidative pyrolysis according to claim 14, characterized in that the separation unit for separating coke particles from the steam/dust/gas flow contains at least two electric precipitators, configured to be turned on periodically as agglomerated carbon black accumulates on the electrodes of the operating electrostatic precipitator. 17. A device for oxidative pyrolysis according to claim 16, characterized in that the electric precipitators are configured to switch the pyrolysis gas flow to an electric precipitator with cleaned electrodes. 18. A device for oxidative pyrolysis according to claim 16, characterized in that the electrostatic precipitators are designed to be shaken and carbon transferred by water vapor or inert gas to the cooling unit. 19. A device for oxidative pyrolysis according to claim 14, characterized in that the fire barrier grid is made in the form of longitudinal channels, the size of which ensures the residence time of the reagents in the channel is no more than 0.003-0.01 s, with a speed of movement of the reagents exceeding the speed of flame propagation at combustion of reagents.