RU2636726C1 - Device for vapour catalytic conversion of natural gas into synthetic gas - Google Patents

Abstract

FIELD: oil and gas industry.SUBSTANCE: device consists of the body with the neck, from the outside of which there is the coaxial casing with the lid and with the bottom in the form of the shell with the flange for connection of the fire burner to its bottom. The neck is fixed inside the axial channel of the flange. The casing is coaxially installed outside the body, and the cooling jacket is outside the casing. The collector for gathering the conversion products is made in the form of the cup coaxially mounted on the outside part of the lid. The ring space between the casing and the body is divided by the horizontal partition into the upper and lower compartments. In the upper compartment there are the reformer tubes of prereforming and primary reforming, pneumatically connected to each other by means of the torus-shaped manifold. The internal space of the body is divided by horizontal partitions into the upper, middle and lower compartments. The secondary reforming reformer tubes are installed in the upper compartment. The internal cavities of the upper and lower compartments are pneumatically connected to each other. In the reformer tubes of prereforming, the primary and secondary reforming, the solid granular catalyst is placed. The internal cavity of the upper compartment is pneumatically connected to the internal cavity of the upper compartment and to the flue gases discharge branch pipes to the collecting manifold. The latter are pneumatically connected to the internal cavity of the collecting manifold, wherefrom the flue gases are sent to the chimney. On the way of the flue gases moving from the collecting manifold to the chimney, the arrangement of the heat-recovery equipment various types can be provided. The internal cavity of the lower compartment is pneumatically connected to the prereforming reformer tubes and with the vapor-gas mixture inlet branch pipe, coming to it from the mixing unit of natural gas and water vapor. The internal cavity, formed by the lid outer surface and the inner surface of the cup, is pneumatically connected to the secondary reforming reformer tubes and to the conversion products exhaust branch pipe.EFFECT: increase of the device operation efficiency and efficiency of using the exhaust gases heat energy.2 cl, 4 dwg, 1 ex

Description

The invention relates to technological equipment used in the chemical, gas processing and other industries for the conversion of natural gas, and in particular to equipment for the production of synthesis gas by steam catalytic conversion of natural gas.

In recent decades, the processing of natural gas, mainly consisting of methane, into various synthetic liquid hydrocarbons (LFG), including into synthetic liquid fuels, methanol, dimethyl ether, etc. This is mainly due to the depletion of the developed resources of traditional oil, rising prices for motor fuel and a sharp tightening of requirements for its environmental characteristics. The organization of production of LNG allows oil and gas companies to draw significant reserves of natural gas into production, the extraction of which was previously considered economically inexpedient, primarily due to the remoteness of the fields from consumers and the lack of transport infrastructure.

The creation of small-tonnage natural gas processing facilities in the SJU, located directly at oil and gas production facilities, is the preferred option that allows solving a number of local environmental, transport and other problems. The majority of specialists consider small-tonnage plants to be installed with an annual capacity (by input raw material) of up to 10 million m ^{3 of} gas. Therefore, the organization of small-scale production of LFG is advisable, first of all, in depleted and low-rate gas fields in order to continue the production of low-pressure natural gas.

It is known that the first step in the production of LNG from natural gas is to produce synthesis gas. The analysis of practical experience has shown that in the process of production of LF, the stage of synthesis gas production is characterized as the most expensive component, which takes up to two thirds of the total energy consumption. Ultimately, it is this circumstance that is the determining factor in assessing the profitability of small-tonnage production of liquid fuel. Therefore, the profitability of the LSS production process is ensured only in conditions of sufficiently large enterprises where utilization of heat losses becomes justified in order to cover high energy costs and reduce the cost of the resulting products. In the case of small-tonnage production of LFG, in most cases it is not possible to achieve profitability of products, therefore, the problem of reducing energy consumption at the stage of synthesis gas production is very relevant and urgent.

Various installations for the conversion of natural gas into synthesis gas, the principle of which is based on the Tandem technology developed at JSC GIAP (Moscow), are widely used in our country and abroad. As an example of the practical implementation of the Tandem technology abroad, one can refer to the energy-saving ammonia plant of the German company Uhde [1].

Unfortunately, due to their overall weight and size characteristics, these plants cannot be effectively used in the conditions of small-tonnage production of LFG and are mainly used in the large-tonnage production of various chemical products, including ammonia.

A known method for the conversion of hydrocarbons by steam reforming and installation for its implementation [2]. A known installation for the conversion of hydrocarbons by steam reforming includes a line for supplying a mixture of purified hydrocarbon feedstocks and steam, a line for outputting the finished product, means for separating the gas-vapor mixture into two streams with lines connected respectively to the first and second primary reforming apparatus with reaction tubes filled with a catalyst , a secondary reforming apparatus, a heater and a partial catalytic reforming apparatus with reaction tubes filled with a catalyst.

The disadvantages of the known installation are the complexity of the design, which makes it difficult to regulate the process of its operation and negatively affects the reliability indicators.

A device for steam catalytic conversion of natural gas into synthesis gas [3], comprising a unit for desulfurization of natural gas, a tube furnace with reaction tubes filled with a catalyst, with an inlet for a gas mixture of natural gas and superheated steam, an external heating zone for the reaction pipes with an outlet for flue gases, a gas burner for external heating of the reaction tubes with an inlet for natural gas and air, heat exchangers for heating natural gas and steam before being fed into a tube furnace, a gas turbine with gene Rathore electric power and synthesis gas burner elektroteplosnabzheniya system.

The main disadvantage of the known device is the insufficiently efficient use of the thermal energy of the exhaust flue gases, as well as the thermal and kinetic energy of the synthesis gas at the outlet of the tube furnace.

The closest to the proposed technical solution for the combination of essential features are a method and device for producing synthesis gas [4], the latter of which can be proposed as a prototype. The known device includes a unit for mixing natural gas and water vapor, a supply pipe for steam and gas mixture, a tubular secondary reforming unit consisting of a housing in which the reaction tubes with a catalyst are installed in the internal cavity, and a fire burner, a collector for collecting conversion products with a discharge pipe, a recovery section heat of exhaust flue gases in the form of a casing, the internal cavity of which is connected with the internal cavity of the housing of the tubular secondary reforming unit, heating elements (snake Eviks) located inside the casing, reaction tubes of pre-reforming and primary reforming with a catalyst, which are installed sequentially outside the casing and are interconnected by means of heating elements.

The main disadvantage of the known device for producing synthesis gas is the lack of specific technical solutions and recommendations regarding the constructive implementation of the main components of the device, which differ significantly in their functional purpose. This circumstance complicates the possibility of practical implementation of the proposed method for producing synthesis gas.

The objective of the invention is to obtain a technical result, which is expressed in increasing the efficiency of the device for steam catalytic conversion of natural gas into synthesis gas and the efficiency of using thermal energy of the exhaust flue gases, as well as in reducing the overall dimensions of the device.

The problem is solved and the technical result is achieved due to the fact that the device for steam catalytic conversion of natural gas into synthesis gas, including a mixing unit for natural gas and water vapor with a pipe for introducing a gas-vapor mixture, a tubular secondary reformer, consisting of a housing, in the inner cavity which is equipped with secondary reforming reaction tubes with a catalyst placed in them, and a fire burner, a collector for collecting conversion products, the inner cavity of which is pneumatically connected on with secondary reforming reaction tubes and with a branch pipe, an exhaust gas heat recovery section in the form of a casing with a cover and a bottom, the internal cavity of which communicates with the internal cavity of the tubular secondary reforming unit housing, the pre-reforming and primary reforming reaction tubes placed inside the casing catalyst, which are installed sequentially and pneumatically connected to each other, while the reaction tubes of the primary reforming are pneumatically connected to the reaction secondary reforming pipes, it is equipped with a cooling jacket with nozzles for supplying and discharging a cooling agent, a toroidal collector and a collecting manifold with nozzles for exhausting flue gases, the cooling jacket being made in the form of a hollow cylinder, and the case and casing are in the form of a hollow cylinder the lower part into a tapering hollow cone, while at the case the tapering conical part ends with a neck, and the casing is coaxially placed outside the casing, and the cooling jacket is outside the casing, while The collector is coaxially mounted on the outside of the casing, and the internal cavity of the collecting manifold is pneumatically connected to the flue gas nozzles, which are evenly placed on the outer surface of the casing, the casing bottom being made in the form of a cylindrical shell with a flange in the axial channel of which the neck is located, while a fire burner coaxially attached to the flange from below, and the annular space between the housing and the casing is divided by means of a horizontal partition into upper and lower compartments, with the top Pre-reforming and primary reforming reaction tubes are coaxially and evenly placed in the compartment, pneumatically connected to each other by means of a toroidal collector, which is installed at the level of the upper end of the body, and the internal space of the body through horizontal partitions is divided into upper, middle and lower compartments, while the internal cavity the upper compartment is pneumatically connected to the internal cavity of the upper compartment and to the nozzles for the removal of flue gases, and the internal cavity of the lower divisions - with pre-reforming reaction tubes and with a nozzle for introducing a vapor-gas mixture, the secondary reforming reaction tubes being coaxially and uniformly placed inside the upper compartment, the inner cavity of the middle compartment of the housing being pneumatically connected to the primary and secondary reforming reaction tubes, and the inner cavities of the upper and lower the compartments are pneumatically connected to each other, and the pre-reforming reaction tubes are placed closer to the inner side surface of the casing, and the reaction tubes are first reforming - closer to the outer side surface of the housing, while the collector for collecting conversion products is made in the form of a cup coaxially attached to the cover of the casing from the outside, while in the cover of the casing an axial channel is made, to which a pipe for removal of conversion products is coaxially connected to the outside . In a particular case, the pre-reforming and primary reforming reaction tubes are placed in the upper compartment at different heights: the primary reforming reaction tubes are installed higher than the pre-reforming reaction tubes.

The design of the device for the steam catalytic conversion of natural gas to synthesis gas is illustrated by the drawings, where: in FIG. 1 shows a General view of the reactor, a longitudinal section; in FIG. 2 is a section AA in FIG. one; in FIG. 3 is a section BB in FIG. 1, in FIG. 4 is a section BB in FIG. one.

A device for steam catalytic conversion of natural gas into synthesis gas consists of a housing 1, outside of which a casing 2 with a cover 3 and a bottom 4 is coaxially placed. The housing 1 and the casing 2 are in the form of a hollow cylinder, which at the bottom goes into a tapering cone. The tapering conical part of the housing 1 ends with the neck 5. The bottom 4 is made in the form of a cylindrical shell, the lower part of which is equipped with a flange for attaching to it from the bottom of the fire burner (not shown in the drawings). The neck 5 is coaxially placed in the axial channel of said flange.

Outside, on the cylindrical side surface of the casing 2, a cooling jacket 6 is coaxially placed with nozzles 7 and 8, respectively, for supplying and discharging atmospheric air. The cooling jacket 6 is in the form of a hollow cylinder.

The collector for collecting conversion products is made in the form of an inverted glass 9, in the bottom of which an axial channel is made. The glass 9 is coaxially mounted on the outside of the lid 3. Outside, a pipe 10 is coaxially connected to the glass 9 to divert the conversion products.

The annular space between the inner side surface of the casing 2 and the outer side surface of the housing 1 is divided by means of a horizontal partition into the upper 11 and lower 12 compartments. In the upper compartment 11, pre-reforming reaction tubes 13 and primary reforming 14 are arranged coaxially and evenly, which are pneumatically connected to each other by a toroidal collector 15 mounted at the upper end of the housing 1. The pre-reforming reaction tubes 13 are located closer to the inner side surface of the housing 2, and primary reforming reaction tubes 14 - closer to the outer side surface of the housing 1. In order to optimize heat transfer with flue gases and minimize the outer diameter of the skin xa 2, the reaction reforming tubes 13 and the primary reforming 14 are installed in the upper compartment 11 at different heights: the primary reforming reaction tubes 14 are placed higher than the reaction reforming tubes 13.

The internal space of the housing 1 by means of horizontal partitions is divided into upper 16, middle 17 and lower 18 compartments. The secondary reforming reaction tubes 19 are coaxially and evenly mounted in the upper compartment 16. The internal cavities of the upper 16 and lower 18 compartments are pneumatically connected.

Inside the reaction tubes of pre-reforming 13, primary 14 and secondary reforming 19, a solid granular catalyst is placed.

The internal cavity of the upper compartment 11 is pneumatically connected to the internal cavity of the upper compartment 16 and to the nozzles 20 for exhausting flue gases into the collecting manifold 21, which is coaxially mounted outside the casing 2. The pipes 20 are uniformly placed on the outer surface of the casing 2 and are pneumatically connected to the internal cavity of the collecting manifold 21, from where the flue gases are directed into the chimney (not shown in the drawings). Along the path of flue gas movement from the collector 21 to the chimney, various types of heat-using equipment may be provided.

The inner cavity of the lower compartment 12 is pneumatically connected to the reaction tubes of the preforming 13 and to the pipe 22 for introducing the vapor-gas mixture coming into it from the mixing unit of natural gas and water vapor 23.

The inner cavity formed by the outer surface of the lid 3 and the inner surface of the glass 9 is pneumatically connected to the reaction tubes of the secondary reforming 19.

The operation of the device for steam catalytic conversion of natural gas into synthesis gas is as follows.

From the mixing unit of natural gas and water vapor 23 through the pipe 22, the vapor-gas mixture is pressurized into the lower compartment 12, where it is additionally heated by contact with the wall of the lower compartment 18. Next, the vapor-gas mixture sequentially passes through pre-reforming reaction pipes 13, toroidal manifold 15 and reaction pipes primary reforming 14, in which it is partially converted. After this, the partially converted vapor-gas mixture enters the middle compartment 17, where it is additionally heated, and from it into the secondary reforming reaction tubes 19. The reforming products exiting the secondary reforming reaction tubes 19 enter the inner cavity of the glass 9 and are discharged out through the pipe 10 .

The stream of hot flue gases, acting as a heat transfer medium, from the fire burner enters the neck 5 of the housing 1. Rising up, the flue gas flow sequentially gives its heat to the compartments 18, 17, 16 of the housing 1, as well as to the reaction tubes of the secondary reforming 19. Having reached the top the end of the housing 1, the flue gas stream changes the direction of movement in the opposite direction, after which it begins to move downward along the annular space between the housing 1 and the casing 2. In this case, the downward flow of flue gases transfers significantly the most part of its thermal energy to the reaction tubes of primary reforming 14 and pre-reforming 13. In the process of this movement and heat exchange, the temperature of the flue gas stream gradually decreases. For this reason, the heating temperature of the casing 1 during operation of the device significantly exceeds the heating temperature of the casing 2, which, in turn, provides the corresponding thermal regime for heating the reactor pre-reforming tubes 13 and primary reforming 14. The primary reforming reaction tubes 14 located near the side wall of the housing 1 get extra heat from her. Therefore, the primary reforming reaction tubes 14 are heated more strongly in the downstream flue gas stream than the pre-reforming reaction tubes 13. From the upper compartment 11, the flue gas flow through the nozzles 22 enters the annular manifold 23 and then is led out.

For external cooling of the casing 2, a cooling jacket 6 is provided with nozzles 7 and 8. Inside the cooling jacket 6, an air compressor is provided with continuous circulation of a cooling agent, which uses atmospheric air.

Information sources

1. Advertising booklet “Ammonia Production Technology” by Uhde, 04/2009, p. 21-24.

2. RF patent No. 2053957, IPC C01B 3/38, publ. 02/10/1996.

3. RF patent No. 2320532, IPC C01B 3/38, publ. 03/27/2008.

4. RF patent No. 2354607, IPC C01B 3/32, C01B 3/34, C01B 3/38, B01J 7/00, B01J 8/02, B01J 3/00, publ. 05/10/2009.

Claims (2)

1. A device for steam catalytic conversion of natural gas into synthesis gas, including a mixing unit for natural gas and water vapor with a nozzle for introducing a vapor-gas mixture, a tubular secondary reforming unit, consisting of a housing in which the secondary reforming reaction tubes are installed in them with a catalyst, and a fire burner, a collector for collecting conversion products, the inner cavity of which is pneumatically connected to the reaction tubes of the secondary reforming and to the outlet pipe com, an exhaust gas heat recovery section in the form of a casing with a lid and a bottom, the internal cavity of which communicates with the internal cavity of the tubular secondary reforming unit housing, reaction tubes of pre-reforming and primary reforming placed inside the casing with the catalyst installed in them, which are installed in series and pneumatically connected among themselves, while the reaction tubes of the primary reforming are pneumatically connected to the reaction tubes of the secondary reforming, characterized in that it is It is equipped with a cooling jacket with nozzles for supplying and discharging a cooling agent, a toroidal manifold and a prefabricated manifold with nozzles for exhausting flue gases, the cooling jacket being made in the form of a hollow cylinder, and the casing and casing are in the form of a hollow cylinder turning into a tapering hollow in the lower part a cone, while at the case the tapering conical part ends with a neck, and the casing is coaxially placed outside the casing, and the cooling jacket is outside the casing, while the prefabricated collector is coaxially mounted for sleep rifles of the casing, and the internal cavity of the prefabricated collector is pneumatically connected to the flue gas nozzles, which are evenly placed on the outer surface of the casing, and the bottom of the casing is made in the form of a cylindrical shell with a flange, in the axial channel of which a neck is placed, while the fire burner is coaxially connected to the flange below, and the annular space between the housing and the casing is divided by means of a horizontal partition into upper and lower compartments, and in the upper compartment coaxially and evenly times reaction tubes of pre-reforming and primary reforming are placed pneumatically connected to each other by means of a toroidal collector, which is installed at the level of the upper end of the body, and the internal space of the body through horizontal partitions is divided into upper, middle and lower compartments, while the internal cavity of the upper compartment is pneumatically connected to the internal cavity of the upper compartment and with nozzles for the removal of flue gases, and the internal cavity of the lower compartment with reaction tubes minga and with a nozzle for introducing a vapor-gas mixture, the secondary reforming reaction tubes being coaxially and evenly placed inside the upper compartment, the inner cavity of the middle compartment of the housing being pneumatically connected to the primary and secondary reforming reaction tubes, and the internal cavities of the upper and lower compartments are pneumatically connected moreover, the pre-reforming reaction tubes are located closer to the inner side surface of the casing, and the primary reforming reaction tubes are closer to the outer lateral the surface of the housing, while the collector for collecting conversion products is made in the form of a cup coaxially attached to the cover of the casing from the outside, while an axial channel is made in the cover of the casing, to which a pipe is connected coaxially to the outside to divert the conversion products. 2. The device according to claim 1, characterized in that the reaction pre-reforming and primary reforming tubes are placed in the upper compartment at different heights: the primary reforming reaction tubes are higher than the reaction pre-reforming tubes.

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