RU2355469C2 - Method of geterogeneous chemical engineering processes performing in adiabatic tube reactor at supercritical pressure - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: invention refers to the versatile engineering chemistry of different materials synthesis by means of chemical initiation of the autothermal geterogeneous reactions in liquid-liquid, and liquid-gas systems while carrying out the processes in adiabatic conditions. The invention can be used in chemical, petrochemical, biochemical and other industries. The method of continuous geterogeneous processes is performed in adiabatic tube reactor (6) at supercritical pressure. The reactor (6) contains the means for supply (1,2) of at least two initial reagents flows, means of its heating (3,4), connected respectively with means for supply (1,2) of the specified initial reagents flows and with the reactor (6); control valve (7), providing the necessary level of supercritical pressure in reactor (6) and evaporative separator (8) in which during pressure reduction at least the part of the flow is divided into flows of low-boiling and high-boiling components. At least one of the initial reagents flow is supplied under supercritical pressure and then assembled with other reagent flow in jet dispersing device (5) providing the linear velocity of the reaction mix 10-40 m/s, then the said velocity drastically decreases to 0.01- 0.03 m/s and the reaction mix interreacts in the tube reactor (6) forming the reaction products flow.

EFFECT: invention allows to increase the rate of a reaction and the conversion of the initial reagents

3 cl, 8 ex, 1 dwg

Description

The invention can be used mainly in the chemical, petrochemical, food, perfumery, cosmetic and pharmaceutical industries when carrying out reaction processes of hydrogenation, oxidation, polymerization, alkylation, amination, nitration, etc.

The specified method is applicable to

- synthesis of organic compounds and their purification;

- polymerization reactions, purification of the polymer from unreacted monomer and polymerization initiator;

- production of synthesis gas, ammonia;

- processing of chemically dirty waste from organic impurities;

- processing of highly toxic, toxic substances and radioactive waste;

- fluid extraction of the target substance;

- obtaining porous polymeric materials;

- production of products and intermediates of medicinal substances;

- the introduction of new substances in the composition of dyes, drugs, polymers;

- the formation of nanoparticles.

Technical field

The invention relates to a method for continuously conducting a heterogeneous chemical process in an adiabatic tube reactor at supercritical pressure.

The invention can be used mainly in the chemical, petrochemical, perfumery, cosmetic and pharmaceutical industries.

State of the art

Known analogues of the invention:

RU 2000107065/12 A, 2002.01.10, RU 2002115626 A, 2003.12.10,

RU 2003124195/15 A, 2005.01.20, RU 2002100202/04 C2, 2000.06.02,

US 00/30765, 10.11.2000, RU 97101490/04 A, 1997.01.30,

RU 2002135638/04 C2, 2006.07.10, RU 2002124707 A, 03/27/2004.

The known method RU 200130923/12 C1, 05/10/2002, the implementation of a chemical reaction in supercritical fluid fluids, in which chemical reactions are carried out periodically in a closed reactor. The disadvantage of this method is the periodic introduction of organic compounds into the volume of supercritical fluids and the periodic withdrawal of reaction products.

The known method RU 2003109040/15 C1, 20.10.2004, the implementation of chemical reactions between organic and inorganic liquid phases at a subcritical temperature of 200 ° C to 300 ° C and a pressure of 5-15 MPa. The disadvantage of this method is to conduct only liquid-phase exothermic chemical processes between organic and inorganic phases.

Closest to the invention in terms of essential features is the method RU 2000113882/04, 06/01/2000, according to which multiphase olefin hydroformylation reactions are carried out in a tubular reactor at a load factor B equal to or greater than 0.8, which is calculated as the quotient of the drop length pressure PD and static pressure PS. The disadvantage of this method is the impossibility of a uniform distribution of the starting reagents in the reaction mass, as well as the formation of intermediate by-products, which complicates the process control.

SUMMARY OF THE INVENTION

An object of the invention is to develop and describe a method for continuously conducting a heterogeneous chemical process in an adiabatic tube reactor at supercritical pressure. The technical result achieved by the invention is to increase the reaction rate and the degree of conversion of the starting reagents.

The above technical result is achieved by the fact that high-speed axisymmetric mixing of the streams of the starting reagents at supercritical pressure creates the conditions for a fast autothermal reaction of the reaction of the reaction mass in the direct-flow tube reactor under essentially adiabatic conditions to almost 100% degree of conversion of the starting reagents to reaction products, after which the products the reactions are dispersed into an evaporative separator with a lower pressure, where it is instantly cooled and removed izkokipyaschih components. With supercritical parameters, hydrogen bonds are almost completely destroyed and the molecules do not show interconnectedness. In addition, their physical properties can be easily changed by varying temperature and pressure. The synthesis of organic compounds at supercritical pressure allows the reaction to be carried out under conditions of molecular dispersion of the reagents in homogeneous high-temperature fluids of low density. The adiabatic regime makes it possible to efficiently use the heat of the reactions themselves, both to maintain the temperature process and to compensate for energy consumption for heating the initial reagents. A straight-through tubular reactor for conducting a heterogeneous chemical process at supercritical pressure has small volumes with high specific productivity. Carrying out a high-temperature process will reduce the viscosity of the solution, which will increase the diffusion coefficient and the speed of the process. The negative effect of high temperature (side processes, decomposition, gum formation) is compensated by the short residence time of the reactants in the reaction zone.

The hardware design of a method for continuously conducting a heterogeneous chemical process in an adiabatic tube reactor at supercritical pressure includes means for supplying (1, 2) the initial flows of reagents, means for heating them (3, 4), a jet dispersant (5), and an adiabatic tube reactor (6) , a reducing device (7) and an evaporative separator (8). The main structural element is a tubular reactor (6), made in the form of a pipe. The initiation of the chemical process is carried out in a jet dispersant (5), passing through which the reaction mass acquires a sufficiently high speed and is converted into a form that facilitates rapid and efficient disintegration into droplets. At the outlet of the jet dispersant (5), diffusion resistance is significantly reduced, which prevents the transfer of reagents through the phase contact surface. In the reactor (6), due to the thermal effect of the autothermal reaction, the temperature of the reaction mixture rises and a transition from isothermal to adiabatic occurs. Carrying out the process in a tubular type apparatus during the piston movement of the reaction mixture significantly reduces the effect of longitudinal mixing of the liquid, which creates conditions that exclude the possibility of chemical bonding of reaction products with incoming feedstock. A feature of the proposed technology lies in a high degree of freedom in varying the process parameters with respect to temperature, pressure, ratio of initial reagents, concentration, residence time of reagents in the reaction zone, and cooling rate of the reaction mixture. This is necessary to change the direction and depth of the reaction upon receipt of a wide range of products, the selection of optimal values of the parameters of the synthesis process, as well as during experimental and research work. The design of the reaction apparatus also ensures the stability of all the given process parameters (reaction time, temperature, pressure) necessary for the optimal implementation of chemical transformations.

The proposed method for conducting a heterogeneous chemical process in an adiabatic tubular reactor at supercritical pressure has several distinctive essential features (design features):

- continuous obtaining of supercritical pressure for at least one initial reagent stream;

- continuous obtaining supercritical temperature for the specified stream of reagents with the formation of supercritical fluids;

- jointly combining the specified stream with another stream of reagents in the jet dispersant (5) with providing in it a linear velocity of the reaction mass equal to 10-100 m / s, preferably 10-40 m / s, and the period of time during which the Association, essentially less than 0.1 seconds, preferably less than 0.01 seconds;

- the interaction of the reaction mass is carried out in the zone of chemical transformations of the tubular reactor (6) under adiabatic conditions in which the linear velocity of the reaction mass is sharply reduced to 0.01-1.0 m / s, preferably to 0.01-0.03 m / s moreover, the period of time during which the reaction mass interacts with the formation of the reaction product stream is essentially less than 180 seconds, during which the temperature of the specified reaction mass increases by at least about 20 ° C, in terms of speed and degree of change Nia which monitor the chemical reaction occurring in the reactor;

- the tubular reactor (6) contains a vertical cylindrical body with a volume ranging from 0.0001 to 0.1 m ³ , preferably from 0.001 to 0.01 m ³ , the distance between the surfaces of which does not exceed 150 mm;

- to facilitate removal of low boiling components, the product stream in front of the control valve (7) is diluted with a supercritical fluid in a ratio of from about 1: 0.2 to 1: 5, preferably from about 1: 0.5 to 1: 2;

- reducing the flow of reaction products through a control valve (7) to a lower-pressure evaporator separator (8), where it instantly cools and separates at least part of the specified reaction product stream into a low-boiling stream and a high-boiling component stream, which essentially complete in less than 0.01 second, preferably less than 0.01 second;

- the required supercritical pressure is measured in the reaction zone of the reactor (6) and the degree of opening of the control valve (7) is controlled depending on the results of these measurements, and the control valve (7) is made with a cone angle of the jet in the range from 50 ° to 180 °, preferably from 90 ° to 140 °.

Scheme

The invention is disclosed in a flow diagram of a continuous method for conducting a heterogeneous chemical process in an adiabatic tubular reactor at supercritical pressure, including supplying the reactant feed streams, heating them, reacting in a tubular reactor, and separating the reaction products.

The hardware design of a method for continuously conducting a heterogeneous chemical-technological process in an adiabatic tube reactor at supercritical pressure includes means for supplying (1, 2) the initial reagent flows, means for heating them (3, 4), a jet dispersant (5), and an adiabatic tube reactor (6, ) a reducing device (7) and an evaporative separator (8).

The tubular reactor (6) has the form of a vertical cylindrical body with a volume of 0.002-0.1 m ³ , closed at one end with a cap through which a jet disperser (5) is passed, and closed at the other end with a bottom having an outlet for reaction products. The jet dispersant (5) is made essentially in the form of a cylindrical pipe having two inlet openings connected by lines with heating means (3, 4), and one outlet for the reaction mixture, connected to the internal cavity of the tubular reactor (6). The tubular reactor (6) also contains measuring means for monitoring temperature and pressure.

The starting reagents are fed separately by means of supplying (1, 2) the starting flows of reagents through heat exchangers (3, 4) to the jet dispersant (5). In the jet disperser (5), heated streams in a turbulent mode are combined and then the reaction mixture enters the tubular reactor (6), where the linear velocity of the reaction mass instantly decreases and under conditions of supercritical density, a quick chemical reaction proceeds. Supercritical pressure in the reaction zone of the reactor is supported by a control valve (7), the degree of opening of which is determined by the pressure regulator. After the control valve (7), the reaction products are reduced to an evaporation separator (8) with a lower pressure, where, as a result of a decrease in temperature, they are separated into low-boiling and high-boiling components.

The implementation of the invention

Example 1. Synthesis of isoprene.

Isobutylene and formaldehyde (1: 1.2 molar ratio) in the presence of an acid catalyst are fed separately to the reactor jet disperser. Isobutylene is preheated in a heat exchanger from about 150 ° C to 180 ° C. The synthesis of isoprene is carried out at a temperature above 150 ° C, a pressure above 4.0 MPa, a residence time of about 60 to 180 seconds. After the reactor, the reaction products enter the separator through a control valve. In the separator due to the increase in gas volume, the reaction products are separated into aqueous and organic phases. Next, the organic phase is fed to the rectification of isoprene, and the aqueous layer is recovered.

The degree of conversion of isoprene is approximately 85-100%.

Example 2. Polymerization of isoprene.

Isoprene, a polymerization initiator, and carbon dioxide are fed separately by high pressure pumps to the jet disperser of the tubular reactor. Isoprene is pre-cooled to a temperature of about minus 55 ° C to 60 ° C, and carbon dioxide is transferred to a supercritical state. The polymerization is carried out at a temperature of about minus 40 ° C to 60 ° C, a pressure of about 30 to 50 MPa, a residence time of about 60 to 180 seconds. After the reactor, the reaction products enter the separator through a control valve. In the separator, due to an increase in the volume of gas, the reaction mass is cooled and crumbly formed (polymer precipitation), while the chain is broken and the polymerization reaction ceases. Carbon dioxide allows you to effectively release polymers from impurities of unreacted monomer and polymerization initiator. Then, the isolated polymer is fed to washing, and unreacted isoprene and carbon dioxide are recycled.

The degree of conversion is approximately 85-100%.

Example 4. The polymerization of isobutylene.

Isobutylene and carbon dioxide in an amount of 0.1-1.0% by weight of the polymer forming in latex in the presence of a catalyst are fed separately by high pressure pumps to the jet disperser of the reactor. The reaction proceeds almost instantly, accompanied by significant heat. Carbon dioxide is used as an initiator and at the same time to lower the reaction temperature. The polymerization is carried out at a temperature of from about minus 55 ° C to 60 ° C, a pressure of from about 30 to 50 MPa.

The degree of conversion is approximately 85-100%.

Example 3. Polymerization of polyacrylate.

Acrylate, a polymerization initiator and carbon dioxide are fed separately by high pressure pumps to the jet disperser of the tubular reactor. Carbon dioxide is heated to a temperature above 31 ° C and create a pressure above 7.3 MPa. Acrylate is preheated in a heat exchanger to 40 ° C. The polymerization is carried out at a temperature of about 35 ° C to 50 ° C, a pressure of about 8.0 to 10 MPa, a residence time of about 60 to 180 seconds. After the reactor, the reaction products enter the separator through a control valve. In the separator, due to a sharp pressure drop, the reaction mass is cooled and crumbly formed (polymer precipitation), and the chain breaks and the polymerization reaction stops. Next, the selected polymer is served for washing.

Modification of the polymer surface is possible, for which metal complexes (for example, copper) are dissolved in supercritical carbon dioxide. During polymerization, the complex is reduced to metal to obtain a nanocomposite more resistant to abrasion. It is also possible the introduction of dyes and stabilizers into the polymer.

Example 5. Hydrogenation of hydrocarbons.

The advantages of supercritical media during hydrogenation are due to the fact that they dissolve gases in themselves 10-20 times higher than in traditional solvents. This is due to the significant free volume of the supercritical medium. The temperature of the process decreases significantly, the reaction rate and selectivity sharply increase.

1) Cyclopentadiene, hydrogen and carbon dioxide are fed separately by high pressure units to the jet disperser of the tubular reactor. Cyclopentadiene is preheated in a heat exchanger to 40 ° C. Hydrogenation is carried out at a pressure of about 12 to 15 MPa, a temperature of about 35 ° C to 50 ° C, a residence time of about 60 to 180 seconds, the molar ratio of hydrogen and CPD is from 1.2: 1 to 1.8: 1.

After the reactor, the reaction products enter the separator through a control valve. In the separator, due to a sharp pressure drop due to an increase in gas volume, the reaction mass is cooled and the fluids evaporate, which return to recycling.

2) Nitrobenzene, hydrogen and carbon dioxide are fed separately to the jet disperser of the tubular reactor, preheated to 40-50 ° C. As a result of the reduction reaction in a slightly acidic medium at pH 3-4, the target product is aniline. The reaction is carried out at a pressure of from 5 to 10 MPa, a residence time of from 60 to 180 seconds.

3) During the reduction of nitrobenzene in concentrated sulfuric acid, para-aminophenol is formed. The reaction is carried out at a pressure of about 5 to 10 MPa, a residence time of about 60 to 180 seconds.

The degree of conversion is approximately 85% - 100%.

Example 6. Obtaining organometallic complexes.

The solution with heavy metal ions, carbon monoxide and a binder (organic ligand) are fed separately to the jet disperser of the tubular reactor. As a result, the metal ion combines with the ligand, forms a complex, and transforms into supercritical carbon dioxide. The reaction is carried out at a temperature of from about 35 ° C to 60 ° C, a pressure of from about 30 to 50 MPa, a residence time of from about 60 to 180 seconds. After the reactor, the reaction products enter the separator through a control valve. An organometallic complex is obtained in the separator due to a sharp pressure drop and intense self-evaporation of carbon dioxide.

The proposed method can grow single crystals of diamond, corundum and many others.

Example 7. Demineralization of water (for thermal power plants), treatment of chemically dirty waste, destruction of highly toxic substances, components of chemical weapons, nuclear fuel cycle.

Chemical waste is processed in the reactor in the presence of oxygen, as a result of which almost all organic substances are oxidized to harmless simplest components and water acquires pronounced antibacterial properties. In the supercritical state, water turns from a polar liquid into a practically nonpolar medium, the diffusion rate increases sharply and its oxidizing ability increases sharply. In aqueous media with supercritical state parameters, resistance to mass transfer is practically absent, which provides all conditions for the rapid occurrence of reactions. As degassing substances use bleach, potassium hypochloride, ammonia water, sodium alkali. Sustainable combustion of organic substances is carried out at a temperature of about 380 ° C to 800 ° C, a pressure of about 22 to 30 MPa, a residence time of about 60 to 180 seconds.

Example 8. Fluid supercritical extraction for the extraction, separation and concentration of organic and inorganic substances.

With supercritical fluid extraction from solutions, it is possible to isolate valuable components in the form of pure substances (including a concentrate of biologically active substances). The process control (transition from extraction to reextraction) is carried out by gradient pressure relief (decrease in the density of the fluid phase). After the reactor, the reaction products enter the separator through a control valve, where the solvent dissolving ability of the extractant decreases due to a sharp pressure drop, the extract is separated, and the fluids are recycled. The advantages of supercritical media as extractants are due to the fact that they extremely efficiently dissolve nonpolar compounds with high diffusion ability and low viscosity. As extractants, carbon dioxide, ethane, ethylene, water are used. Of the fundamentally applicable gases, carbon dioxide is most technically available. The extraction of natural substances with carbon dioxide is carried out at a temperature not exceeding 100 ° C, a pressure of about 10 to 30 MPa, a residence time of about 60 to 180 seconds.

Claims (3)

1. A method for continuously conducting a heterogeneous chemical process in an adiabatic tube reactor (6) at supercritical pressure, including means for supplying (1, 2) of at least two initial reagent flows, means for heating them (3, 4), connected by lines respectively, with means for supplying (1, 2) of said initial reagent flows and a reactor (6), a control valve (7) that maintains the required supercritical pressure in the reactor (6), and an evaporation separator (8), in which at least throttling h Part of the reaction product stream is divided into a stream of low-boiling and high-boiling components, characterized in that at least one of the initial reagent stream is supplied with supercritical pressure, then it is combined with another reagent stream in a jet dispersant (5) to provide a linear reaction rate in it a mixture of 10-40 m / s, then in the tubular reactor (6) the linear velocity of the reaction mass is sharply reduced to 0.01-0.03 m / s and in the zone of chemical transformations of the tubular reactor (6) under the adiabatic conditions interact Corollary obtained reaction mass to form a reaction product fluid. 2. The method according to claim 1, characterized in that the process is carried out in a tubular reactor (6) containing a vertical cylindrical body with a volume ranging from 0.002 to 0.1 m ³ , preferably from 0.004 to 0.01 m ³ . 3. The method according to claim 1, characterized in that the control of the chemical reaction occurring in the tubular reactor (6) is carried out according to the speed and degree of increase in the temperature of the reaction mass.