RU2770519C1 - Method for producing hydrogen and liquid hydrocarbons by beta and steam conversion of hydrocarbon gases - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to a method for producing hydrogen and liquid hydrocarbons by beta and steam conversion of hydrocarbon gases, in which the flow of the initial gas feedstock is fed into the reactor, ionized by electronic radiation with simultaneous exposure to electromagnetic radiation. Water is introduced into the feedstock stream in proportions from 1:20 to 1:2 by weight, ionization is carried out by a flow of electrons with an energy from 0.3 to 10.0 MeV at a gas-water mixture temperature from 5 to 200°C, static pressure from 0.1 to 0.2 MPa and an average energy density of electromagnetic radiation from 0.1 to 10 kW/m3.EFFECT: increase in the energy efficiency of the process.8 cl, 3 dwg

Description

The invention relates to methods and devices for producing hydrogen and liquid products containing carbon, oxygen and hydrogen atoms in molecules from gaseous hydrocarbons (with partial elimination of hydrogen and reconfiguration of atomic bonds).

The terms used in the present description have the following interpretation:

- ionizing radiation: exposure to accelerated electrons, which causes excitation, radicalization and ionization (the formation of ions of both signs) of the substance of the environment in which it propagates;

- hydrocarbon-containing gas : methane, ethane, propane, butane or their mixtures in any proportion;

- energy efficiency, or efficiency in terms of energy consumption : an indicator estimated by the ratio of energy expended to the amount of useful product at the output of the process. In the present description, energy efficiency is evaluated by the yield of hydrogen, which is the most targeted product.

A number of methods and devices for the conversion of light gaseous hydrocarbons into liquid ones are known, based on the irradiation of the source gas from the alkane group or its mixture with water vapor with a stream of accelerated electrons.

All these methods do not provide the energy efficiency of the process, and therefore there is still no information about their large-scale industrial application.

For example, a patent application is known for a method and device for converting gaseous hydrocarbonates (natural gas) and steam into liquid fuel in an amount from 1 gram to 100 tons by irradiation with an electron beam with an energy of (0.5 ... 10) MeV for 1 s and up to over 300 s at an absorbed dose rate from 1 kGy/s to and over 8 kGy/s [WO 2021007550 A1].

The proposed design of the reaction chamber does not ensure the full use of the energy of the electron beam, and a significant part of the energy consumed is used to obtain unwanted by-products. Even if we assume that among the millions of combinations of the declared regimes there are those that can provide an economically justified process, the application does not contain information about such regimes and, in essence, is only a statement of the problem, but not its solution.

There is a known method of converting light hydrocarbons into heavier ones by exposing them to a beam of accelerated electrons, and for a more complete use of the energy of electrons, the initial flow of hydrocarbons is divided into two, directed oppositely across the direction of electron movement, and then the total flow is turned in the direction of electron movement [DE 10163474 A1]. The reaction chamber in this case has a T-shape, where the horizontal part of the letter corresponds to the gas supply channels, and the vertical part corresponds to the actual reaction part, where the gas and electron flows move along.

It would seem that with a sufficient length of the reaction part of the chamber, all the energy of the electrons will be given to the process of gas ionization. However, due to the scattering of electrons by gas molecules, the direction of their movement changes, and a significant part of them, not yet wasting their energy, settles on the walls of the chamber, heating them. The process is inefficient in terms of energy consumption.

There is a known method for the conversion of methane, ethane or propane into macromolecular compounds, in which the initial mixture of gases is introduced into a magnetic field and irradiated with a stream of electrons, as well as a device for implementing this method, containing an electron accelerator with a beam sweep, a horseshoe-shaped permanent magnet, between the poles of which a reactor is located (reaction chamber), having a foil window in one of the walls for the release of electrons [US 2892946]. In this case, the magnetic field, being transverse with respect to the trajectories of electrons at the entrance to the reactor, wraps the electrons in a spiral, narrowing as they lose energy to ionize the gas. Due to this, the electrons do not reach the walls of the reactor and completely give their energy to the technological process.

The known method is also inefficient in terms of energy consumption due to the need to create a strong magnetic field, taking into account almost the speed of light of electrons, in the entire volume of the reactor, which in industrial installations can reach several cubic meters.

A common disadvantage of all conversion methods using only electron irradiation is that a significant part of the energy of the electron beam is spent on the formation of transition products (3/4), the spin state of which is at the triplet level, which is not capable of forming the desired products. During the transition from the excited state to the ground state, the main part of the energy received by them is radiated onto the walls of the reaction chamber, without contributing to an increase in the product yield.

There are a number of methods for converting light hydrocarbons into heavier ones with the associated production of hydrogen by exposure to microwave radiation on a mixture of gaseous light (with a small number of carbon atoms in the molecule) hydrocarbons with steam [WO 200612388, WO 2009145936, RU 2513622, RU 2427527, RU 2588258 , RU 2646607, US 5328577]. The performance of all known methods is limited by the power of commercially available microwave generators operating in continuous mode.

The closest to the proposed technical essence and the achieved result is a conversion method carried out in a reactor consisting of two reaction chambers, in which a gaseous mixture of light hydrocarbons is introduced into the first reaction chamber with a volume of 0.01 m ³ , ionized by a pulse (no more than 1 μs) electron radiation with electron energy (0.05 ... 1) MeV with simultaneous excitation of molecules by an electromagnetic field with a frequency of 2400 MHz at an average energy density of the electromagnetic field in the chamber of about 1500 kW / m ³ , and then transferred to the second reaction chamber, where it is treated with an electromagnetic field with a frequency of 1600 MHz, while lowering the level of absorbed energy of microwave radiation [RU 2149884]. That is, the process is carried out in two stages. Information about the energy efficiency of the process is not given in the source.

The disadvantage of the known method is its low energy efficiency. The productivity of the process due to the low average power of pulsed accelerators operating with a high (at least 10 ⁵ ) duty cycle is so low that the known method is of no industrial interest.

The objective of the present invention is to create an energy-efficient method for the conversion of light hydrocarbons from the group of alkanes to heavier ones with the associated production of hydrogen.

The technical result of using the proposed method is to increase the energy efficiency of the process.

This result is achieved by the fact that in the known method for producing hydrogen and liquid hydrocarbons by beta- and steam reforming of hydrocarbon gases, in which the feedstock stream is fed into the reactor, ionized by electron radiation with simultaneous exposure to electromagnetic radiation, water is introduced into the feedstock stream in proportions from (1:20) to (1:2) by mass, ionization is carried out by a stream of electrons with an energy of (0.3 ... 6) MeV at a temperature of a mixture of gas with water (5 ... 200) ° C, a static pressure of (0.1 ... 0.2) MPa and the average energy density of electromagnetic radiation (0.1 ... 10) kW / m ³ .

The proposed method is characterized by the following parameters:

- Electromagnetic radiation is set rather weak, excluding heating, only to ensure spin transitions in radical pairs.

- Exposure to electromagnetic radiation is carried out at a frequency of 40 Hz - 40 GHz.

- Water is introduced into the raw material in the form of steam.

- Water is introduced into the feedstock in the form of a dispersed liquid.

- Before being processed by electrons, the mixture flow is twisted in a three-dimensional cylindrical or conical spiral.

- The mixture is fed into the reactor tangentially to its wall at an angle of (60…90)° to the direction of its movement during processing.

- The mixture is processed in a reactor made in the form of a Rank tube.

Water in a liquid or vapor state within the stated limits minimizes energy consumption at a given yield of liquid hydrocarbons and hydrogen, reduces the sensitivity of the yield to fluctuations in the molecular weight of the feedstock.

By carrying out the process at the declared temperature and pressure of the mixture at the inlet to the reactor, the maximum yield of liquid hydrocarbons is achieved with minimal energy consumption and the reliability of the equipment used is sufficient for industrial use.

Due to the processing of the mixture at an energy of (0.3 ... 10) MeV, the energy efficiency of the process increases.

Because the energy density ^of electromagnetic radiation does not exceed 10 kW/m

Due to the fact that the mixture flow is swirled before electron treatment, the energy efficiency of the process is increased.

Due to the process in the Rank tube, its energy efficiency increases, since the flow of the swirling processed mixture passes twice, back and forth in a spiral and back along the axis, through the irradiation zone with an intermediate selection of a liquid product.

The essence of the invention is illustrated by drawings, which show the main elements of the installation that implements the proposed method, as well as the trajectory of the particles of the mixture in it.

In FIG. 1 schematically shows the installation for implementing the proposed method, in which water in liquid form is mixed into the feedstock stream, and the mixture is twisted in the form of a three-dimensional cylindrical spiral.

In FIG. 2 schematically shows the relative position of the reactor chamber and the inlet pipe.

In FIG. Figure 3 schematically shows the installation for implementing the proposed method, in which water in the form of steam is mixed into the feedstock stream, and the mixture is twisted in the form of a three-dimensional conical spiral.

The proposed method is carried out as follows.

Stream 1 of a hydrocarbon-containing gas, consisting, for example, of one of the first four members of the homologous series of methane or a mixture thereof, is fed through a pipe 2 into the reactor, which includes a chamber 3 having a cylindrical (Fig. 1) or conical (Fig. 3) shape, connected at the ends with devices 4 and 5 for product selection.

Simultaneously with flow 1, water 7 is supplied into the pipe 2 or directly into the chamber 3 through the pipe 6 along with the flow 1 in liquid (Fig. 1) or gaseous (in the form of steam) (Fig. 3) state. Depending on the composition of the feedstock and the main purpose of the process (mainly hydrogen production or gas liquefaction), the amount of water supplied can exceed from one to ten units relative to the mass of gas, i.e. be in proportion from (20:1) to (2:1), and further, when justifying the limiting values of the process parameters, the words “decreases”, “decreases in a noticeable way” mean a statistically significant decrease in energy efficiency by 20% of the maximum value.

To accelerate the evaporation of water supplied in liquid form, it is dispersed to a particle size of 10 microns or less, for which the end of the pipe 6 is equipped with a nozzle 8 (Fig. 3). Entering the chamber 3, the input stream of a mixture of hydrocarbon-containing gas with water is treated with electrons and an electromagnetic field, more precisely, the magnetic component of the electromagnetic field.

For the best mixing of the mixture and increasing the uniformity of ionization of the entire gas-water mixture flow entering the reactor, it is swirled, for example, by introducing it tangentially to its axis (Figs. 1 and 2), i.e. to the direction of movement of the mixture during processing. This gives the molecular trajectories in the reactor a vortex shape, increasing the rate constants of radiation-chemical reactions by three orders of magnitude. Molecules in a swirling flow move along the walls of chamber 3 in a spiral, cylindrical if chamber 3 has a cylindrical shape (Fig. 1), or conical if chamber 3 has a conical shape (Fig. 3). In the drawings, the turns of the trajectory spiral are conventionally shown by dotted lines. Giving the chamber a conical shape is expedient, since as the mixture passes along the chamber 3, the properties of the flow processed by the electrons change.

Reflecting from the reflector 9, installed with a gap relative to the walls of the chamber 3 coaxially with it, the flow of the gas-water mixture, partially processed by electrons and physical fields, is directed in the opposite direction along the axis of the chamber 3, inside the vortex spiral of the input flow. The directions of movement of forward and reverse flows in the drawings are shown by arrows. At the same time, part of the flow moving near the walls of the chamber 3, through the gap between them and the reflector 9, enters the device 4 for separating and collecting the liquid product 10, which in the simplest case includes a sump 11.

Part of the processed forward flow that has passed through the gap, after the separation of hydrogen and the requested liquid product 10 from it, can be sent to the inlet 2 for re-treatment. Along the way, the resulting hydrogen can be separated from it. An adjustable valve 12 is used to control the flows.

During the reverse movement to the inlet part of the chamber 3, the flow containing heavier radiolysis products is re-processed by electrons and the magnetic component of the electromagnetic field, which increases the energy efficiency of the process.

The recycled stream is captured by the socket 5 and sent to a device for separating hydrogen and liquid product.

The vortex flow entering the chamber is ionized by electron radiation, with the electrons withdrawn from vacuum into the gas through window 13, covered with separating foil 14. Depending on the transverse size of chamber 3 and the composition of the feedstock, the energy of electrons removed to chamber 3 can range from 0.3 up to 10.0 MeV.

The execution of the reactor in the form of a Ranque tube, as shown in the drawings, provides a double passage of a part of the mixture through the stream of accelerated electrons: first in the form of a near-wall flow, and then in the form of an axial flow in the opposite direction..

The temperature of the mixture flow at the inlet to the reactor should be in the range (5...200)°C.

The pressure in the mixture in the reactor must be within (0.1 ... 0.2) MPa.

The flow of the mixture entering the reactor simultaneously with its ionization by electrons is exposed to the magnetic component of the electromagnetic field with a frequency of 40 Hz - 40 GHz at an energy density introduced into the reactor (0.1...10) kW/m ³ . To enter the electromagnetic field into the reactor, an antenna connected to the generator 15 is used, the design of which depends on the frequency of the input field. So, for microwave frequencies in the range of 300 MHz - 40 GHz, horn, loop (pos. 16 in Fig. 3) or slot antennas are optimal. Antennas for lower frequencies can be frame, as conditionally shown in pos. 17 in FIG. 1, and contain from one to several thousand turns, depending on the frequency of the input electromagnetic field. Directional antennas are preferred, which emit an electromagnetic wave, the Poynting vector of which is directed along the axis of the camera 3.

The proposed method uses the property of the magnetic component of an electromagnetic wave to affect the spin states of radical pairs that can participate in recombination mainly in the singlet state. The alternating field of the magnetic component of the electromagnetic wave resonantly changes the population of singlet and triplet states of radical pairs.

Electromagnetic radiation is set to provide spin transitions in radical pairs.

The required parameters of electronic and electromagnetic radiation are selected experimentally according to the maximum yield of the requested product, depending on the composition of the feedstock and the design of a particular reactor.

In all methods and devices known from the prior art for gas-to-liquid conversion, electromagnetic radiation is used to ionize the treated mixture, i.e. to form radical pairs. The effects of spin dynamics, on which the proposed method is based, were simply not taken into account and were not noticed during the experiments due to the fact that the energy introduced into the reactor was several orders of magnitude greater than that required to change the spin state of radical pairs, and the frequency of electromagnetic radiation did not were selected in resonance with the frequencies of spin transitions, and those provided by industrial equipment for microwave heating, mainly 2.45 and 1.2 GHz, i.e., were used. frequencies that are not the most optimal for influencing the resonant value of interatomic bonds.

Experiments on a laboratory facility showed that the energy consumption for hydrogen production from methane and water vapor under given conditions is about 0.5 eV/mol H ₂ or 11.2 kcal/mol, which indicates the participation of chain processes in obtaining a valuable product. The cost of the product is estimated at about $0.2/kg of hydrogen.

Claims (8)

1. A method for producing hydrogen and liquid hydrocarbons by beta and steam reforming of hydrocarbon gases, in which the feed gas feed stream is fed into the reactor, ionized by electron radiation with simultaneous exposure to electromagnetic radiation, characterized in that water is introduced into the feed feed stream in proportions from 1:20 to 1:2 by mass, ionization is carried out by an electron flow with an energy of 0.3 to 10.0 MeV at a gas-water mixture temperature of 5 to 200°C, a static pressure of 0.1 to 0.2 MPa and average energy density of electromagnetic radiation from 0.1 to 10 kW/m³. 2. The method according to claim 1, characterized in that electromagnetic radiation is set to provide spin transitions in excited molecules, ions and radical pairs, the occurrence of which is due to the action of accelerated electrons and secondary gamma quanta. 3. The method according to claim 1, characterized in that the exposure to electromagnetic radiation is carried out at a frequency of 40 Hz to 40 GHz. 4. The method according to claim 1, characterized in that water is introduced into the feedstock in the form of steam. 5. The method according to p. 1, characterized in that dispersed water with a droplet size of less than 10 microns is introduced into the feedstock. 6. The method according to claim 1, characterized in that before processing by electrons, the mixture flow is twisted, giving the molecular trajectories a vortex shape of a three-dimensional cylindrical or conical spiral. 7. The method according to claim 6, characterized in that the mixture is fed into the reactor tangentially to its wall at an angle of 60 to 90° to the direction of its movement during processing. 8. The method according to p. 6, characterized in that the mixture is processed in a reactor made in the form of a Ranque tube.

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