WO2023247223A1

WO2023247223A1 - Device and method for injecting a gas into a transport pipe for a fluid

Info

Publication number: WO2023247223A1
Application number: PCT/EP2023/065526
Authority: WO
Inventors: Guillaume Ferrand; Benjamin RODIER; Kevin GAULT
Original assignee: Grtgaz
Priority date: 2022-06-23
Filing date: 2023-06-09
Publication date: 2023-12-28
Also published as: FR3136996A1

Abstract

The invention relates to a device (10) for injecting a secondary fluid into a transport pipe (11) for a main fluid, which device comprises an injection duct (15), comprising: - a stationary portion (16) on the transport pipe, forming a slideway; - a movable and retractable element (17) forming a slider, the stationary portion and the movable element thus forming a sliding connection or a sliding pivot connection. The device also comprises a means (20) for moving the distal end of the mobile element in the transport pipe to a predetermined distance from the centre of the transport pipe; - a valve (12) for connecting to the pipe; and - a means (13) for connecting, to the injection duct, a pipe (14) for circulating the secondary fluid.

Description

DESCRIPTION

TITLE OF THE INVENTION: DEVICE AND METHOD FOR INJECTING A GAS INTO A FLUID TRANSPORT PIPE

Technical field of the invention

The present invention relates to a device and a method for injecting a gas into a fluid transport pipeline. It applies, in particular, to gas transport and distribution networks and in particular to the supply of a transport network.

State of the art

Renewable gases correspond to new energy sources and are part of a context of development of so-called “clean” and “green” energies. In particular, such gases offer a viable and lasting possibility of diversifying the available carbon-free energy sources. Renewable gases have the advantage of being completely in line with sustainable development dynamics.

However, the compositions of renewable gases as well as their properties differ from those of fossil natural gas and therefore from gas transported in a pipeline of a transport network. When a renewable gas is injected, for example into a gas transport network, there is a problem of homogeneity of the final composition of the gas after mixing. Such homogeneity is an important parameter to ensure, for example, the transport and delivery of gas conforming to the specifications of a transport network. This homogeneity of the gas transported must be obtained at the shortest possible distance after injection. Such a mixing distance is measured between the injection point of the renewable gas and the location of the gas transport pipe where the homogeneity of the resulting mixture is consistent and can therefore be delivered to a user.

For example, when a secondary fluid is of a different nature compared to the main fluid into which it is injected then there is a need to ensure the homogeneity of the mixture produced.

If, moreover, the secondary fluid to be injected is outside certain requirements, but the quality of the main fluid allows the mixture of the two fluids to be compliant, then the need to obtain homogeneity of the mixture is even more important. Furthermore, the conformity of the gas transported is, for example, defined according to standards and criteria for the composition of the gas transported to a delivery point. In addition, certain renewable gas compounds, notably hydrogen, are responsible for increased corrosion in transportation pipelines.

However, maintenance constraints of a transport network are also present. In particular, such maintenance is ensured by the passage of an inspection piston inside a gas transport pipe. The presence of a fixed element inside the pipe, for example, as close as possible to the center of the transport pipe, constitutes an obstacle to the passage of the piston.

Document FR 2 683 465 describes a device for injecting gas into a container or pipe of a liquid containing impurities or foreign bodies, such as purification channels, sewer pipes (pipes) or the like , comprising a hollow body connected to the container or pipe. The cavity of this body opens into this container or pipe. The device comprises valves and gas injection means connected to a pipeline supplying the gas, these injectors being removably connected to this body and these valves closing when these injection means separate from said body.

Document WO 2013/088031 describes a method of injecting an additive into a liquid conduit of diameter D. This method comprises the following steps: a sample of liquid is taken from the conduit; an additive and the sampled liquid are mixed to form a first mixture outside the conduit; and this first mixture is injected into the conduit using an injector comprising a hollow tube of which at least part is placed inside the conduit and contains at least one passage whose outlet orifice delivers the first mixture in the conduit, this injector allowing the first mixture to reach at least 90% of the section of the conduit at a distance, downstream of the injection location of the first mixture, of five times D.

Document US 3,460,765 describes an apparatus for injecting liquid into a gas pipeline, which comprises a housing having a central passage adaptable to an inlet conduit of the pipeline. A ball valve rotates in this housing, between two positions, one of which allows the passage of a liquid injector.

Document AU 2017 232 216 describes a dosing apparatus adapted to allow the selective movement of a lance between an extended state and a retracted state. In the extended state, the dosing device enables the distribution of substances into a pipeline. In the retracted state, the lance is located inside the dosing device allowing selective closing or opening of the valve to either remove the metering device from the valve or move the lance into the extended state for dispensing substances into the pipeline. The dosing apparatus includes means for preventing expulsion of the dispensing means from the retention chamber and means for allowing adjustment of the distance between the retention chamber and a distal end of the dispensing means.

Document DE 197 00 462 describes an injection point for the introduction of additives into turbulent fluids (or suspensions, or flows of fluidized solid materials). The cross section through which the main stream flows is gradually narrowed by deliberate deformation of the wall surrounding the stream (e.g. a pipe or channel) and is expanded again over its entire surface at a designed pinch point to act as a swirl breakaway edge to achieve mixing of the additive with the main stream. The pinch point is produced by plastic deformation of the main passage wall by the application of an external force, and any resulting weakening is compensated by the use of external reinforcement. The additive is injected through one or more holes in the wall enclosing the main flow in the pinch point region.

Prior art solutions describe the use of static mixers to quickly obtain consistent homogeneity. However, such systems require the installation of a bypass of the gas transport pipeline to avoid obstructing the path of the maintenance piston. They consist of adding a parallel secondary pipeline connected, at its inlet and outlet, to the main pipeline, with the injection taking place in the parallel pipeline. These solutions are expensive and their implementation disrupts the operation of the transport pipeline during the construction phase. Finally, the homogenization distance of the gas after the joining of the main pipeline and the secondary pipeline is very high, with its consequences in terms of corrosion and potential impossibility of delivering the inhomogeneous gas.

Presentation of the invention

The present invention aims to remedy all or part of these drawbacks.

To this end, according to a first aspect, the present invention aims at a device for injecting a secondary fluid into a pipeline for transporting a main fluid according to claim 1. The terms “proximal” and “distal” refer, respectively, to what is located closest to the point of attachment of the movable element on the means of movement, and to what is furthest away from it.

Thanks to its technical characteristics, the device allows optimal injection of a secondary fluid, such as renewable gas, into a pipeline transporting a main fluid, such as natural gas. In particular, the device makes it possible to position the injection point of the secondary fluid according to predetermined constraints. These constraints are, for example, a targeted homogeneity of the composition of the main fluid downstream of the injection at a predetermined distance in the transport pipeline. Indeed, such a device allows improved mixing efficiency, compared to a simple pooling of two fluids. Reliable and rapid homogeneity of the total fluid mixture downstream of the injection is therefore obtained. Thus, such homogenization makes it possible in particular to reduce the mixing distance and therefore the length of the overhead pipes. In particular, a reduction in certain costs is achieved, such as the costs associated with analysis elements to validate a compliant specification of the main fluid transported in the transport pipeline and downstream of the injection. A compliant specification is, for example, in line with certain standards to be respected.

Furthermore, the retractability of the mobile element of the device makes it possible to remove part of the injection pipe positioned inside the transport pipe. Such removal is, for example, carried out so as not to cause physical discomfort during a maintenance operation requiring the passage of an instrumented piston inside the transport pipe for inspection purposes. Thus, the device is suitable for pipes requiring maintenance by passing a device such as an instrumented piston. In addition, such removal is, for example, carried out for the maintenance of the mobile element. The device also allows easy removal of the mobile element, facilitating the preparation of maintenance operations on the transport pipeline and/or the mobile element. Such removal is carried out, for example, manually.

In addition, when removing the movable element from the pipe, optimal sealing is ensured by the device. In particular, the connection valve of the device contributes to such sealing.

Finally, the device is adaptable to different nature of secondary and main fluid defined, for example, by variable compositions, densities and/or flow rates. For example, the device is suitable for injecting renewable gas into a natural gas transport pipeline. Furthermore, the easy and adaptable sizing of the device makes it easily integrated into an existing main fluid transport pipeline.

Since no artery diversion is required, setting up the device which is the subject of the invention is simpler and less expensive than setting up a diversion with a static mixer. We can thus avoid unavailability of the transport network. In optional embodiments, the means of connection to the circulation pipe of the secondary fluid to be injected further comprises a connection valve.

Thanks to these arrangements, the device allows the flow of injected secondary fluid to be stopped. Such a stop is particularly carried out when the removal of the mobile element is necessary, for example, to carry out a maintenance operation. For example, successive closing of the connection valve, a regulation valve and the connection valve secures the device to carry out, for example, a maintenance operation. Thus, the insulation and independence of the injection pipeline are ensured according to operational needs.

In optional embodiments, the distal end of the movable element includes a diffuser.

Thanks to these arrangements, the device makes it possible to improve the homogenization of the gas downstream of the injection. In particular, an improvement in the speed and reliability of homogenization is obtained. For example, when injecting secondary fluid into a main fluid transport pipeline, consistent homogeneity is obtained over a few meters. Such homogeneity is, for example, obtained when injecting renewable gas into a natural gas transport pipeline. Thus, the device makes it possible to further reduce the mixing distance. Furthermore, a diffuser is a compact element that is easy to incorporate into the device.

In optional embodiments, the diffuser includes a main fluid anti-return system.

Thanks to these arrangements, the device makes it possible to ensure sealing of the mobile retractable element and thus guarantees insulation and safety of the transport pipe. In other words, the anti-return system of the device makes it possible to prevent the infiltration of main fluid in the opposite direction into the mobile retractable element and thus constitutes a first safety barrier. In optional embodiments, the anti-return system includes a primary fluid anti-return ball.

Thanks to these provisions, the tightness of the device is guaranteed by the use of a ball having adequate insulation reliability and being, moreover, easily removable and cleanable. The combination of effective sealing and ease of maintenance of such an anti-return system is thus ensured.

In optional embodiments, the device further comprises a means of obtaining at least one measurement of a physical quantity representative of the composition of the main fluid downstream of the injection.

Thanks to these arrangements, the device makes it possible to monitor the composition of the main fluid downstream of the injection and to compare this composition to a reference value. Such a composition is, for example, representative of the homogeneity of the main fluid. In particular, such monitoring makes it possible to highlight the homogeneity of the main fluid downstream of the injection and to compare this homogeneity to a reference value. For example, such a reference value is set by the recommended specifications for the main fluid circulating in the transport network.

In optional embodiments, the device further comprises a means of controlling the flow rate of the secondary fluid injected as a function of the composition of the main fluid downstream of the injection.

Thanks to these arrangements, the device makes it possible, for example, to adapt the flow rate of the secondary fluid injected as a function of the results obtained during a comparison between the composition of the main fluid downstream of the injection and a reference value. The reference value is, for example, fixed according to specifications determined for the main fluid circulating in the transport pipe. For example, when the composition does not comply with a reference value, for example with specifications imposed for the main fluid, the injection rate of the secondary fluid is modified until this composition complies. This corresponds, for example, to a reduction in the injection rate of the secondary fluid so that the composition of the main fluid is again in line with fixed specifications.

In optional embodiments, the device further comprises means for controlling the displacement means, configured to control the position of the distal end of the movable element as a function of the composition of the main fluid downstream of the 'injection. We can thus adapt the height of the injection point in the pipe as a function of the injected and passing flow rates in order to reduce the distance for obtaining homogeneity. For example, the height is determined by CFD calculations (acronym for Computational fluid dynamics, designating the study of fluid dynamics by the numerical resolution of the equations governing it).

In optional embodiments, the device further comprises:

- a means of obtaining at least one measurement of a physical quantity representative of the composition of the main fluid upstream of the injection and

- a means of controlling the flow rate of the secondary fluid injected as a function of the composition of the main fluid upstream of the injection.

Thanks to these arrangements, the device makes it possible to adapt the flow of secondary fluid according to the composition of the main fluid, in the case where the secondary fluid does not comply with the specifications of the transport network. An adaptation of the flow rate of the secondary fluid is then carried out as a function of the quantity of main fluid circulating in the main pipe.

In optional embodiments, the device further comprises:

- a means of obtaining a main fluid flow in the pipe and

- a means of controlling the flow of secondary fluid injected as a function of the flow of main fluid in the pipe.

Thanks to these arrangements, the device allows adaptation of the flow of secondary fluid as a function of the flow of the main fluid upstream or downstream of the injection. In particular, when the secondary fluid injected does not comply with the specifications of the transport network, the device allows adaptation of the flow rate of the secondary fluid injected to the flow rate of the main fluid so that the fluid mixed downstream of the injection remains compliant with these specifications.

According to a second aspect, the present invention aims at a method of injecting a secondary fluid into a pipeline for transporting a main fluid, characterized in that it comprises:

- a step of connecting a device which is the subject of the invention to the main fluid transport pipe,

- a step of connecting the device to a circulation pipe for the secondary fluid to be injected, and - a step of moving the distal end of the movable element of the device in the transport pipe to a predetermined distance from the center of the pipe.

The aims, advantages and particular characteristics of this process being similar to those of the device which is the subject of the invention, they are not recalled here.

Brief description of the figures

Other advantages, aims and particular characteristics of the invention will emerge from the following non-limiting description of at least one particular embodiment of the device and the method which are the subject of the present invention, with reference to the appended drawings, in which:

[Fig 1] represents, schematically, a first particular embodiment of the device which is the subject of the invention,

[Fig 2] represents, schematically, a second particular embodiment of the device which is the subject of the invention, and

[Fig 3] represents, schematically and in the form of a flowchart, a particular succession of steps of the process which is the subject of the invention.

Description of embodiments

The present description is given on a non-limiting basis, each characteristic of an embodiment being able to be combined with any other characteristic of any other embodiment in an advantageous manner.

The indefinite articles "a" and "an", as used in the description and in the claims, are to be understood to mean "at least one", unless clearly indicated otherwise.

The expression "and/or", as used herein and in the claims, should be understood to mean "either or both" of the elements thus conjoined, i.e. that is, elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and/or" must be interpreted in the same way, i.e. "one or more" of the elements thus conjoined. Other elements may possibly be present, other than the elements specifically identified by the "and/or" clause, whether or not they are related to these specifically identified elements. Thus, by way of non-limiting example, a reference to "A and/or B", when it is used in conjunction with open language such that "comprising" may refer, in one embodiment, to A only (possibly including elements other than B); in another embodiment, to B only (possibly including elements other than A); and in yet another embodiment, to A and B (possibly including other elements).

As used herein in the description and in the claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating elements in a list, "or" or "and/or" must be interpreted as inclusive, that is, the inclusion of at least one, but also more than one, a number or a list of elements, and, optionally, additional elements not listed. Only terms clearly indicating the contrary, such as "only one of" or "exactly one of", or, when used in the claims, "consisting of", refer to the inclusion of a single element of 'a number or list of elements. In general, the term "or" as used herein should only be interpreted to indicate exclusive alternatives (i.e. "one or the other, but not both") when it is preceded by terms of exclusivity, such as "either", "one of", "only one of" or "exactly one of".

As used in the present description and in the claims, the expression "at least one", with reference to a list of one or more elements, must be understood as meaning at least one element chosen from one or more multiple items in the item list, but not necessarily including at least one of each item specifically listed in the item list and not excluding any combination of items in the item list. This definition also allows for the optional presence of elements other than the specifically identified elements in the list of elements to which the expression "at least one" refers, whether or not they are related to these specifically identified elements. Thus, by way of non-limiting example, "at least one of A and B" (or, equivalently, "at least one of A or B", or, equivalently, "at least l 'one of A and/or B') may refer, in one embodiment, to at least one, optionally including more than one, A, without B present (and optionally including elements other than B); in another embodiment, at least one, optionally comprising more than one, B, without A present (and optionally comprising elements other than A); in yet another embodiment, at least one, possibly comprising more one, A, and at least one, optionally comprising more than one, B (and optionally comprising other elements); etc.

In the claims, as well as in the description below, all transitional expressions such as "comprising", "including", "carrying", "having", "containing", "involving", "holding", "composed of ", and others, must be understood as open, that is, as meaning including, but not limited to. Only the transitional expressions "consisting of" and "consisting essentially of" are to be understood as closed or semi-closed transitional expressions, respectively.

The term “fluid” refers to a physical state of matter, corresponding to a gas, a liquid or a mixture of the two. For example, the secondary fluid is composed, at least partially, of renewable gas. “Renewable gas” means gas that is not extracted from fossil reserves. For example, a renewable gas is made of biomethane. For example, biomethane comes from a methanization unit. For example, the main fluid is composed, at least partially, of natural gas.

The term “natural gas” refers to a gaseous mixture of compounds belonging to the hydrocarbon family. Natural gas notably contains a volume portion of methane of at least 80% relative to the total volume of the gas. For example, natural gas contains a volume portion of methane equal to 95% relative to the total volume of the gas.

The term “mixing distance” 37 refers to a distance between the injection point of the secondary fluid and the location in the transport pipe where the fluids form a homogeneous mixture.

Throughout the description, the terms “upstream” and “downstream” are used to designate the position of the elements in the direction of circulation of a fluid, and depend on the fluid whose circulation is observed.

The term “specification” refers to one or more characteristics stated so that a fluid is considered to conform to a predetermined or determined specification. For example, a specification is standardized or variable over time. For example, the characteristics relating to a specification are defined by a percentage of one or more chemical compounds present in the fluid. Chemical compounds include the majority species or impurities. For example, when the main fluid consists of natural gas, a Current specification of natural gas circulating in a transport pipeline requires a percentage of hydrogen (of formula H2) less than or equal to 2%.

Note that the term “specification” can also be used to characterize a secondary fluid to be injected. In particular, a secondary fluid to be injected is, for example, compliant with predetermined specifications, but has a different composition from a main fluid.

The term “actuator” refers to a mechanical actuation system including, for example, a drive motor or a cylinder.

The term “communicating portable terminal” refers to any device equipped with:

- a man-machine interface and

- a means of communicating wired or non-wired signals, such as an antenna or a port to receive a network cable for example.

For example, such a portable communicating terminal is:

- a smartphone,

- a digital tablet or

- a portable personal computer.

Throughout the description, we call “upper” everything that is at the top in Figures 1 and 2 and “lower” everything that is at the bottom in Figures 1 and 2. The terms “vertical” or “height” arise from these definitions. The transport pipe illustrated in Figure 1 is substantially cylindrical and locally has a central axis denoted A. We call "internal" everything which is close to or oriented towards this axis A and "external" what is further from this axis or oriented opposite to this axis A.

Note now that the figures are not to scale.

We observe, in Figure 1, which is not to scale, a schematic view of an embodiment of the device 10 which is the subject of the invention. The device 10 is a device for injecting a secondary fluid into a transport pipe 11 of a main fluid. In Figure 1, the secondary fluid is represented by a simple dotted arrow and the main fluid by a simple solid arrow.

We observe, in Figure 1, that the device 10 comprises an injection pipe 15, comprising a part 16 fixed on the transport pipe 11 and a movable and retractable element 17. The fixed part 16 forms a slide and the movable and retractable element 17 forming a slide. The fixed part 16 and the movable element 17 thus form a sliding connection or a sliding pivot connection. The mobile element 17 presents a proximal end 18 which remains in the injection pipe 15 and a distal end 19 which is moved in the main pipe 11 by a movement means 20. The injection pipe 15 also comprises a connection valve 12 to the main fluid transport pipeline. The device 10 also comprises a means of connection 13 to the injection pipe 15 of a circulation pipe 14 of the secondary fluid to be injected.

The moving means 20 of the movable element 17 moves the distal part 19 in the transport pipe 11 up to a predetermined distance from the center of the transport pipe 11.

The connection valve 12 ensures, when closed, the sealing of the connection associated with the injection device 10 while maintaining the transport pipeline 11 operational. Furthermore, the connection valve 12 allows, when it is open, the passage of the movable element 17 towards the main pipe 11. The internal opening of the connection valve 12 therefore has dimensions greater than those of the mobile element 17.

In embodiments, the connection valve 12, also called an isolation valve, is a gate valve known to those skilled in the art.

In variants, the connection valve 12 is a ball valve known to those skilled in the art. Note that manual closure of the injection line 15 is possible with such ball valves. Note that a ball valve, a gate valve or a spring valve can also constitute the connection valve 12.

In embodiments, an additional connection valve is present in the device 10. In particular, such a valve can be added to the device 10 when the pressure inside the pipe 11 can momentarily be much higher than the pressure in the secondary pipe 14 or in the injection pipe 15. The presence of such an additional valve improves the sealing and therefore the safety of the device 10.

In embodiments (not shown), the device 10 further comprises a counter-pressure system. In particular, the back pressure system is coupled to the connection valve 12. Such a system is configured to exert a pressure greater than the pressure present in the transport pipeline 11. In this way, the loss of main fluid during the extraction of the mobile element 17 is limited. Such a counter-pressure system is implemented in particular during the removal of the mobile element 17 upstream of the closing of the connection valve 12.

The counter-pressure system is similar to a bell or any other element which can be connected in a sealed manner to the elements of the injection tool 15 and makes it possible to provide a counter-pressure greater than the effective pressure in the injection tool. 'injection. Note that there are several ways to manage the back pressure on the injection system.

1/ In operation, the secondary fluid is brought to a pressure greater than the pressure inside the pipe 11, via an external compression system. As a result, the secondary fluid is always at a higher pressure than the main fluid in order to diffuse the secondary fluid into the main fluid inventory of pipeline 11 and the pressure difference is dissipated in element 22, the nozzle broadcast.

2/ If the secondary fluid is no longer injected or if there is a loss of injection, a first barrier present in element 19, the injection tool acts as a non-return valve. Another non-return valve located on the secondary pipeline 14 reinforces this barrier and limits the loss of main fluid.

3/ Furthermore, a motorized isolation valve (not shown) closes as soon as the injected flow rate of the secondary fluid is zero.

4/ For the maintenance or dismantling phases of element 15, a pressurization bell, a mobile element external to the tool 15, is positioned on the element 15 enclosing the injection tool in a sealed manner from of the isolation valve 12. A counter pressure greater than the pressure of the main pipe 11 is then applied in order to move the fluid towards the main pipe and allow the extraction of the element 15 until the total closure of the valve element 12 to complete the insulation of the system. The bell in question is then depressurized via a purge to allow the intervention.

The connection means 13 is known to those skilled in the art for connecting a pipe and a pipe or two pipes. In embodiments, such as that shown in Figure 1, the connection means 13 to the pipe of the secondary fluid to be injected further comprises a connection or isolation valve 21. This connection valve 21 connects the device 10 and the secondary fluid circulation pipe 14. Preferably, the connection means 13 comprises a flange 30 which ensures sealing and connection between the device 10 and the circulation pipe 14 of the secondary fluid. Note that the flange 30 can be positioned before or after the connection valve 21.

In embodiments, such as that shown in Figure 1, the connection means 13 comprises a flow meter 34 disposed downstream of the connection valve 21. Preferably, the flow meter 34 is an electromagnetic flow meter.

The connection valve 21 is preferably closed upstream of the removal of the mobile element 17. Preferably, the removal of the mobile element 17 is thus carried out according to the following successive steps:

- closing the connection valve 21,

- removal of the mobile element 17 from the transport pipeline 11 and

- closing the connection valve 12.

In embodiments, such as that shown in Figure 1, the fixed part 16 comprises a substantially cylindrical housing 27 forming a slide. Note that housing 27 is composed of two parts, an upper part and a lower part, each part being arranged on either side of the connection valve 12.

In embodiments, such as that shown in Figure 1, the fixed part 16 comprises a connection base 28 forming a housing of the lower part of the housing 27. In other words, the housing of the connection base 28 has dimensions at less complementary to the dimensions of the housing 27. For example, when the housing 27 and the connection base 28 respectively form a cylinder trunk, the diameter of the connection base 28 is greater than the diameter of the housing 27. The connection base 28 corresponds to a connection ensuring the connection of the fixed part 16 to the connection valve 12 and to the transport pipe 11.

In embodiments, such as that shown in Figure 1, the connection element 28 comprises a cylinder trunk 29 and a connection flange 36. The connection flange 36 ensures sealing and connection to the transport pipe 11 . In variants, the connection element 28 comprises a plurality of connection flanges 36. In other variants, the connection element 28 is welded to the transport pipe 11.

In embodiments, such as that shown in Figure 1, the movable element 17 is an injection rod. The distal end 19 of the movable element 17 comprises a diffuser 22 of injected fluid. For example, the diffuser 22 is a pierced basket or pierced cylindrical diffuser known to those skilled in the art. Preferably, the diffuser 22 includes a fluid anti-return system. For example, the non-return system includes a fluid non-return ball, in particular a ball non-return valve. In other embodiments, the diffuser is a diffusion nozzle. In variants, the diffuser has a “T” shape or a longitudinally pierced tube whose opening is oriented against the flow of the main fluid circulating in the transport pipe 11.

We observe, in Figure 1, that the device 10 comprises the means of movement 20 of the movable end 19 and in particular of the diffuser 22. The means of movement 20 positions the end 19 at a predetermined distance from the center (on the axis A) of the transport pipeline 11 or completely retracts the movable element 17 of the main pipeline 11. In the device 10, the movement means 20 is arranged between the connection means 13 and the connection valve 12.

In embodiments, the movement means 20 comprises:

- an end piece 31 with thread and

- a gear (not shown), possibly fitted with a crank (not shown).

The gear is, for example a pinion gear and the movable element 17 of the injection pipe 15 has notches or teeth complementary to those of the pinion gear. For example, such notches or teeth are present, when the movable part 15 is a cylinder trunk, on the surface of the cylinder trunk. In particular, the notches or teeth are distributed along a straight line corresponding to a generator of the cylinder trunk. The implementation of such a rack ensures the movement of the distal end 19 towards or away from the center A of the transport pipe 11. In embodiments, the use of the crank for the movement towards or away distance of the distal end 19 from the center of the transport pipe 11 is manual. Thus, an operator carries out the movement of the injection pipe 15 directly.

In variants, the gear is operated semi-automatically or automatically. For example, the device 10 includes a man-machine interface for an operator to send activation or deactivation commands to an actuator, coupled to the gear. For example, the man-machine interface includes a means of displaying, such as a screen, information representative of the positioning height of the distal end 19 of the injection pipe 15. In other embodiments, the device 10 comprises a communicating terminal sending activation or deactivation commands to an actuator.

In embodiments, such as that shown in Figure 1, the movement means 20 further comprises a screwed nut 32 disposed between the end piece 31 and the portion of the injection pipe 15 connected to the connection means 13 Such a nut ensures sealing of the displacement means 20.

In embodiments, such as that shown in Figure 1, the displacement means 20 further comprises a purge 33.

Note that the movement means 20 allows access to a plurality of positions of the distal end 19 of the movable element 17 in the transport pipe 11. For example, depending on the flow rate, the density, the nature and the composition of the secondary fluid injected and/or the flow rate, density, nature and composition of the main fluid in the pipe 11, the distal end 19 is located at the lowest point, in the center or even flush with the pipe transport 11. For example, if the density of the secondary gas injected is lower than the density of the main gas of the transport pipe 11, the position of the distal end 19 below the center of the transport pipe 11 minimizes the distance of mixture 37.

In embodiments (not shown), the device 10 additionally comprises an overpressure or bell system. Such a system is configured to prevent leaks of fluid to the outside, that is to say any leak of fluid out of the device 10, the transport pipe 11 and the pipe 14 for circulating the secondary fluid.

In the second embodiment illustrated in Figure 2, the device 35 comprises all the elements of the device 10. The device 35 further comprises a means 23 for obtaining at least one measurement of a physical quantity representative of the composition of the main fluid downstream of the injection. When the main fluid is a gas, a physical quantity representative of the composition corresponds, for example, to the volume concentration or the volume fraction of a chemical species constituting such a gas. For example, when the gas is natural gas, the volume concentration of hydrogen is determined by the means of obtaining 23.

In embodiments, the means of obtaining 23 comprises a sensor for measuring the composition of the fluid conveyed by the transport pipe 11. In other examples, the means of obtaining 23 comprises a means of sampling the main fluid circulating in the transport pipe 10. Preferably, such a sampling means is coupled to a system for analyzing the composition of the fluid sampled. For example, when the main fluid comprises at least partially a gas, a gas composition analysis system comprises an analysis unit configured to carry out gas chromatography, with the acronym “GC” (from the English “GC”). gas chromatography"). Preferably, such a unit is coupled to a mass spectrometer, the gas composition analysis system being a unit with the acronym “GC-MS” (from the English “gas chromatography-mass spectrometry”).

In embodiments, a compression station present in the network of the pipeline 11 comprises a measurement sensor of a means of obtaining 23. In other words, such a sensor is not arranged inside the pipeline 11.

In embodiments, the device 35 further comprises a means 26 for controlling the flow rate of secondary fluid injected as a function of the composition of the main fluid downstream of the injection by the obtaining means 23. We obtain thus a feedback control of the composition of the mixed fluid, a control which ensures compliance with specifications by this mixed fluid.

For example, the control means 26 includes a pressure regulator. In other examples, the control means 26 also includes a regulation valve. Note that, in these embodiments, the means 26 for controlling the flow of injected secondary fluid and the means for obtaining 23 are connected directly or indirectly, for example, by a wired or wireless connection.

In other embodiments, the device 35 further comprises means for controlling the movement means 20. Note that the control means is configured to control the position of the distal end of the movable element. Such control is carried out in particular as a function of the composition of the main fluid downstream of the injection. In particular, such a measurement is provided by the means of obtaining 23. For example, the control means is an actuator comprising a motor coupled to a crank of the means of movement 20. Note that, in these embodiments, the means control of the movement means 20 and the obtaining means 23 are connected directly or indirectly, for example, by a wired or wireless connection. In embodiments, such as that shown in Figure 2, the device 35 further comprises:

- a means 24 of obtaining at least one measurement of a physical quantity representative of the composition of the main fluid upstream of the injection and

- a means 26 for controlling the flow rate of the secondary fluid injected as a function of the composition of the main fluid upstream of the injection.

Note that the characteristics stated for the means of obtaining 23 are transposable to the characteristics of the means of obtaining 24. The means of obtaining,

23 and 24, may be of the same nature or of a different nature.

In embodiments, the obtaining means 24 is configured to perform a read from a database. In particular, such a database includes data corresponding to physical quantities representative of the composition of the main fluid upstream of the injection as a function of time. For example, such data are instantaneous measurements determined for a second, a minute, an hour, a day and/or a year. In embodiments, time is a continuous or discrete variable.

In variants, the composition of the main fluid provided by the means of obtaining

24 corresponds to a result of a calculation taking into account:

- the composition, upstream of the injection, of the main fluid circulating in the transport pipeline 11 and

- the composition and/or flow rate of a fluid, distinct from the secondary fluid and the main fluid, injected into the transport pipe 11 and upstream of the injection carried out by the device 35.

In embodiments, the control means 26 includes a pressure regulator. In other examples, the control means 26 also includes a regulation valve. In other words, the control means 26 comprises a pressure regulator and a regulation valve. Such a regulation valve corresponds, for example, to the connection valve 21 of the connection means 13. The connection means 13 thus comprises the control means 26. Note that, in these embodiments, the means of control 26 of the flow of injected secondary fluid and the means of obtaining 24 are connected directly or indirectly, for example, by a wired or wireless connection. In other examples, the control means comprises the connection valve 12 to the transport pipe 11 of the main fluid. In embodiments, such as that shown in Figure 2, the device 35 further comprises:

- a means of obtaining a main fluid flow rate in the transport pipe and

- a means 26 for controlling the flow of secondary fluid injected as a function of the flow of main fluid in the transport pipe.

In embodiments, the means for obtaining a main fluid flow rate comprises a flow meter. Preferably, the means of obtaining 25 is a flow meter measuring an average flow rate on a transverse surface of the pipe 11, such a surface being delimited by the director of the cylindrical pipe 11.

In embodiments, the main fluid flow rate provided by the obtaining means 25 corresponds to the main fluid flow rate upstream of the injection. In variants, the main fluid flow rate supplied by the means of obtaining 25 corresponds to the main fluid flow rate downstream of the injection.

In embodiments, the obtaining means 25 is configured to perform a read from a database. In particular, such a database includes data corresponding to flow rates of the main fluid upstream or downstream of the injection as a function of time. For example, such data are predictions or averages of time-stamped measurements.

In variants, the composition of the main fluid supplied by the means of obtaining 25 corresponds to a result of a calculation taking into account:

- the flow rate of the main fluid circulating in the transport pipe 11 and

- the composition and/or flow rate of a fluid, distinct from the secondary fluid and the main fluid, injected into the transport pipe 11 upstream of the injection carried out by the device 35.

In embodiments, the control means 26 includes a pressure regulator.

In embodiments, the control means 26 comprises a control valve. In other words, the control means 26 comprises a pressure regulator and/or a regulation valve. Such a regulation valve corresponds, for example, to the connection or isolation valve 21 of the connection means 13. The connection means 13 then comprises the control means 26. Note that, in embodiments, the means 26 for controlling the flow of injected secondary fluid and the means for obtaining 25 are connected directly or indirectly, for example, through a wired or wireless connection. In embodiments, the control means comprises the connection valve 12 to the transport pipe 11 of the main fluid.

In variants, the control means 26 comprising a pressure regulator is distinct and independent of the connection valve 21. Thus, the insulation of the mobile element 17 carried out by the connection valve 21 and the injection of the secondary fluid regulated by the pressure regulator are distinct.

Note that the means of obtaining, 23, 24 and 25, can be combined in the same device 35.

For all of the controls, in open loop or closed loop, mentioned above, the person skilled in the art knows, depending on the characteristics of the primary fluid and the secondary fluid and the expected specifications of the fluid resulting from their mixture, to determine the servo function. In particular, if the secondary fluid does not meet these specifications, those skilled in the art know how to determine the ratio of the flow rates of the main fluid and the secondary fluid so that the fluid resulting from their mixture meets these specifications. For example, if the specification applicable to the transported gas prohibits a dihydrogen H2 content greater than 2%, if the main fluid has a dihydrogen H2 content of X%, with H2 of Y%, with Y greater than 2, the person skilled in the art controls the flow of the secondary fluid to a value lower than the product of the main flow by the ratio (2-X)/(Y-2).

In variants (not shown), the height of the diffuser 22 in the transport pipe 11 is subject to measured, estimated or predicted values of flow rates, density, temperatures, compositions of the main fluid and/or the secondary fluid and/or to values of environmental variables, to reduce the mixing distance 37 and/or reduce the risk of corrosion. According to a first example, the more dihydrogen H2 the secondary fluid contains, the more the diffuser 22 is positioned in the lower part of the pipe 11 to take into account the lower density of the dihydrogen and the risks of corrosion of the pipe than a high rate of dihydrogen represents. According to a second example, the more the secondary fluid has a high relative density compared to the main fluid, the more the diffuser 22 is positioned in the upper part of the pipe 11 to take into account the Archimedes force exerted by the main fluid on the fluid secondary. If the densities are identical, the diffuser 22 is positioned in the center of the pipe 11. We observe, in Figure 3, a schematic view of an embodiment of the method 40 which is the subject of the invention. The injection method 40 of a secondary fluid into a pipeline for transporting a main fluid comprises:

- a step 41 of connecting a device which is the subject of the invention to the fluid transport pipeline, - a step 42 of connecting the device to a circulation pipeline of the secondary fluid to be injected and

- a step 43 of moving the distal end of the movable element of the device in the transport pipe to a predetermined distance from the center of the pipe. Preferably, the means of the device 10 or 35 are configured to implement the steps of the method 40 and their embodiments as explained above and the method 40 as well as its different embodiments can be implemented by the means of device 10.

Claims

1. Device (10, 35) for injecting a secondary fluid into a transport pipe (11) of a main fluid, characterized in that it comprises:

- an injection pipe (15), comprising:

- a fixed part (16) on the transport pipe, forming a slide,

- a movable and retractable element (17) forming a slide, having a distal end (19) and a proximal end (18), the fixed part and the movable element thus forming a slide connection or a sliding pivot connection,

- means for moving (20) the distal end of the movable element in the transport pipe up to a predetermined distance from the center of the transport pipe, and

- a connection valve (12) to the transport pipeline; And

- a means of connection (13), to the injection pipe, of a circulation pipe (14) of the secondary fluid to be injected.

2. Device (10, 35) according to claim 1, wherein the connection means (13) to the circulation pipe (14) of the secondary fluid to be injected further comprises a connection valve (21).

3. Device (10, 35) according to one of claims 1 or 2, wherein the distal end (19) of the movable element (17) comprises a diffuser (22).

4. Device (10, 35) according to claim 3, wherein the diffuser (22) comprises a fluid anti-return system.

5. Device (10, 35) according to claim 4, wherein the anti-return system comprises a fluid anti-return ball.

6. Device (35) according to one of claims 1 to 5, which further comprises a means of obtaining (23) at least one measurement of a physical quantity representative of the composition of the main fluid downstream of the injection.

7. Device (35) according to claim 6, which further comprises a means (26) for controlling the flow rate of secondary fluid injected as a function of the composition of the main fluid downstream of the injection.

8. Device (35) according to claim 6 or 7, which further comprises means for controlling the displacement means (20), configured to control the position of the distal end (19) of the movable element in function of the composition of the main fluid downstream of the injection.

9. Device (35) according to one of claims 1 to 8, which further comprises:

- a means of obtaining (24) at least one measurement of a physical quantity representative of the composition of the main fluid upstream of the injection and

- a means (26) for controlling the flow rate of the secondary fluid injected as a function of the composition of the main fluid upstream of the injection.

10. Device (35) according to one of claims 1 to 9, which further comprises:

- a means of obtaining (25) a main fluid flow in the transport pipe and

- a means (26) for controlling the flow of secondary fluid injected as a function of the flow of main fluid in the transport pipe.

11. Method for injecting (40) a secondary fluid into a pipeline (11) for transporting a main fluid, characterized in that it comprises:

- a step of connecting (41) a device (10, 35) according to one of claims 1 to 10 to the fluid transport pipe,

- a step of connecting (42) the device to a circulation pipe for the injected secondary fluid and

- a step of moving (43) the distal end (19) of the movable element of the device in the transport pipe to a predetermined distance from the center of the pipe.