EP3807569A1

EP3807569A1 - Mobile backfeeding installation

Info

Publication number: EP3807569A1
Application number: EP19745686.6A
Authority: EP
Inventors: Daniel Dufour; Francis BAINIER; Marc VANBALEGHEM; Alban SESMAT; Gérard CATTOEN
Original assignee: GRTgaz SA
Current assignee: GRTgaz SA
Priority date: 2018-06-15
Filing date: 2019-06-17
Publication date: 2021-04-21
Anticipated expiration: 2039-06-17
Also published as: US20210270424A1; PL3807569T3; FR3082598B1; ES2961728T3; WO2019239082A1; US11719389B2; CA3103749A1; EP3807569C0; EP3807569B1; FR3082598A1

Abstract

The invention relates to a backfeeding installation (30), comprising: - modules (31 to 35 and 37) having the following functions: at least one compressor for compressing gas, an automaton for controlling the operation of at least one compressor, at least one sensor for quality compliance of the gas circulating in the compressor, at least one counter for counting a flow of gas circulating in the compressor and at least one filter for filtering the gas circulating in the compressor; and - an interconnection module (36A, 36B) between the other modules and with a gas network (15) at a first pressure and a gas network (10) at a second pressure higher than the first pressure. At least one of said modules is mobile and configured to be transported on a single vehicle integrally and in operational state by removable connection to the interconnection module and to an energy source.

Description

MOBILE CASH BACK INSTALLATION

TECHNICAL AREA

The present invention relates to a mobile reverse installation. It applies, in particular, to gas transport networks to export surplus renewable gas from a distribution network to a transport network, which has a much higher storage capacity.

STATE OF THE ART

Biogas production is experiencing strong growth in Europe and its development conditions the creation of a sustainable methanisation sector. In the following, "biomethane" defines the gas produced from raw biogas from anaerobic methanisation of organic waste (biomass) or by high temperature gasification (followed by synthesis by methanation); purified and treated so as to make it interchangeable with natural gas from the network.

While the most common recovery method is the production of heat and / or electricity, recovery in the form of fuel and the injection of biomethane into the natural gas network are also being developed.

The injection of biomethane into the natural gas network is already carried out in Europe. In a context of strong development of biomethane, natural gas distributors are faced with situations of lack of an outlet. In fact, consumption by domestic customers varies on average from 1 to 10 between winter and summer on public distributions. The injection of biomethane is initially only possible if it is carried out at a flow lower than the minimum flow recorded during periods of lower consumption or if the biomethane is produced as close as possible to consumption. When production exceeds the quantities consumed, this tends to saturate the distribution networks during hot seasons. This situation limits the development of the biomethane production sector through congestion in the natural gas distribution networks. Several solutions have been identified to solve this problem: the networking of distribution networks to increase the consumption capacities of the biomethane produced by the multiplication of connected consumers, the modulation of the production of biomethane according to the seasons and consumption needs, the micro -liquefaction and compression to store biomethane productions during seasons of low consumption, the development of gas uses (for mobility, in particular), as well as the creation of back-up stations between gas distribution and transport networks natural.

Back-up facilities are thus one of the solutions identified to develop biomethane injection capacities. These installations make it possible to export surplus biomethane from a distribution network to the transport network, by compressing and reinjecting them into this transport network, thereby benefiting from its greater gas storage capacity. Thus, producers should no longer limit their production and the profitability of their projects would be more easily ensured. The countdown station is a work of the transport operator allowing the transfer of gas from the distribution network to the transport network with a large storage capacity, via a gas compression station. The countdown station can be located either near the detent station or at another location where the transport and distribution networks intersect.

The countdown therefore incorporates a gas compression function to adapt it to the constraints imposed by the downstream flow of this compressor, that is to say the transport network. The current countdowns are fixed installations in which the compressors are placed in buildings. Each compressor is driven there by an electric motor connected to the electrical network.

For economic reasons, some countdowns are only equipped with a compressor ensuring 100% of the flow. These reverses therefore do not guarantee normal operation in the event of a single compressor failure. But installing a second compressor providing 100% flow to provide backup in the event of a fixed reverse countdown is an expensive solution. In the event of a back-up station failure, biomethane producers can no longer supply their biomethane production. Likewise, if a new biomethane supplier is connected without having to install a back-up station, which becomes necessary, biomethane producers are penalized. Similarly, the need for a countdown station can be ad hoc or an investment in such a countdown station can be deferred, in particular while awaiting other connections from biomethane producers, with the same consequences for this sector. .

In addition, the configurations of the distribution networks change, especially when a biogas supplier is connected to it and injects or disconnects biogas. At the same time, gas consumption on this distribution network can increase or decrease, for example when installing a factory or a large consumer area or when it is shut down. The back-up capacity may therefore find itself, temporarily or permanently, surplus or insufficient.

More generally, the existing back-up installations do not allow an evolution of their dimensioning according to the need.

The current countdowns are fixed installations where the compressors are placed in buildings. The current countdowns therefore do not allow speed and flexibility of intervention on the networks.

STATEMENT OF THE INVENTION

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

The present invention relates to a reverse installation comprising:

modules with the following functions:

o at least one compressor to compress gas,

o an automatic operating control of at least one compressor, o at least one conformity sensor for the quality of the gas circulating in the compressor,

o at least one counter for counting a flow of gas circulating in the compressor and

o at least one filter to filter the gas circulating in the compressor; and an interconnection module between the other modules and with a gas network at a first pressure and a gas network at a second pressure greater than the first pressure;

wherein at least one of these modules is mobile, configured to be transported, fully and in working condition by removable connection to the interconnection module and to an energy source, on a single vehicle.

Thanks to these provisions, a fixed reverse installation can easily be supplemented by a mobile module to increase its compression capacities or to make up for a fixed element that has broken down or is undergoing maintenance or updating. Thus, during a temporary increase in the capacity requirements of the back-up installation (transient overcapacity of biogas producers, transient drop in consumption by gas consumers), an additional mobile compressor module is added to the back-up installation. And we withdraw it once this temporary increase is complete.

The purpose of the mobile countdown installation object of the invention is to address the following three purposes in particular:

provide mobile back-up and a higher availability rate in the event of a breakdown of an existing mobile back-up installation,

offer the possibility of deferring an investment in a fixed countdown installation, offer a temporary solution in case of emergency (need or delay) and

to respond to ad hoc or too low needs to justify an investment on a fixed countdown installation. This therefore makes it possible to strengthen the development of injection capacities already initiated by fixed reverse installations and thus to maximize the reception of biomethane injection projects.

In embodiments, all modules of the countdown installation are mobile, configured to be transported, fully and in working condition by removable connection to the interconnection module and to an energy source, on a single vehicle.

Thanks to these provisions, temporary countdown needs, for example pending the installation of a fixed countdown installation, can be met by a mobile countdown installation.

In embodiments, the countdown facility includes a mobile autonomous power source.

Thanks to these provisions, the mobile countdown installation does not need to be connected to the electrical network in order to operate.

In embodiments, the mobile electrical power source is a generator operated by a vehicle engine.

Thanks to these arrangements, the same motor can be used to actuate different modules, or even to set the vehicle in motion.

In embodiments, the power source is a motor supplied with gas at the first pressure. Thanks to these provisions, the primary energy source is the gas which is to be compressed, which avoids having to transport this primary energy.

In embodiments, at least one module includes a gas detector and / or a fire detector.

Thanks to these provisions, the safety of the mobile countdown installation is ensured by at least one of the modules that it comprises.

In embodiments, at least one compressor is mechanically actuated by a vehicle engine.

Thanks to these arrangements, the same motor can be used to actuate the compressor and to set the vehicle in motion.

In embodiments,

In embodiments, the interconnection module further comprises:

a mobile distribution unit for distributing gas from a gas network at a first pressure to several modules via an interface and

a mobile collection unit for collecting the gas coming from each said module at a second interface.

Thanks to these provisions, the gas flows between the different modules are easily set up for the operation of a back-up installation.

In embodiments, the controller is configured to control the operation of a plurality of compressors based on the compression capacity of the operational compressors.

Thanks to these provisions, it is easy to change the compression capacities of the reverse installation. Indeed, a compressor module can easily be put into service or removed in this installation.

In embodiments, the back-up installation further comprises at least one recycling circuit provided with a valve, configured to expand gas at the outlet of a compressor and inject it upstream or at the inlet of said compressor , the automaton being configured to control the operation of the valve of the recycling circuit as a function of the compression capacity of the operational compressors which are put into operation jointly.

Thanks to these provisions, the stability of the distribution network is ensured, regardless of the operational compression capacity of the compressors operated jointly, that is to say simultaneously or with a reduced time delay.

In embodiments, at least one module of the countdown installation is integrated into a standard container.

In embodiments, at least one module of the countdown installation is mounted on a vehicle.

Thanks to each of these provisions, the transport of this module is facilitated.

In embodiments, at least one compressor is mechanically actuated by a vehicle engine. In embodiments, at least one module of the reverse installation is supplied with electrical energy by a generator mounted on the vehicle.

Thanks to each of these arrangements, the actuation of the compressor does not require oversizing of the electrical supply of the back-up installation, compared to the supply of only the fixed compressors.

In embodiments, the countdown installation includes a mobile analysis laboratory that is air-conditioned and protected from shocks and vibrations, a laboratory comprising a common chromatograph for measuring THT and the composition of the gas.

Thanks to these provisions, the same chromatograph allows several measurements.

In embodiments, the countdown installation comprises a correlation calorimeter implementing the composition of the gas obtained by a chromatograph.

Thus, the calorific value of the gas is measured indirectly and at a lower cost.

In embodiments, the countdown installation includes a hygrometer, for example ceramic.

As this hygrometer is less sensitive than other types of hygrometers to vibration, the design of the mobile countdown installation is made easier.

In embodiments, the reverse installation includes a dehydrating skid and a volumetric counter.

In embodiments, the reverse installation comprises means for valve control in series downstream of at least one compressor.

In embodiments, the reverse installation includes a spillway in series, downstream of at least one compressor.

The valve and the overflow means facilitate the operation of the compressor, in particular when it is started.

In embodiments, the back-up installation comprises a system for storing bottled gas and a means for withdrawing gas at different times, for example with pneumatic valves.

Thanks to these provisions, the composition of the gas can be determined in a deferred manner, which reduces the cost of the installation, compared to the incorporation of a chromatograph.

In embodiments, the back-up installation comprises a fire central, with detector and extinguisher, as well as a gas detection means.

In embodiments, the back-up installation comprises an electrical cabinet isolated from each compressor by a wall comprising watertight bulkheads.

Thanks to each of these provisions, the security of the installation is reinforced.

BRIEF DESCRIPTION OF THE FIGURES

Other advantages, aims and characteristics of the present invention will emerge from the description which follows, given for explanatory purposes and in no way limiting, with reference to the appended drawings, in which: FIG. 1 represents, in the form of a block diagram, a reverse installation known in the prior art,

FIG. 2 represents, in the form of a block diagram, a reverse installation object of the invention,

FIG. 3 represents, diagrammatically, the assembly of different modules of a countdown installation object of the invention,

FIG. 4 schematically represents modules of a mobile embodiment of a reverse installation,

FIG. 5 schematically represents a fixed countdown installation comprising a mobile module,

FIG. 6 represents, in the form of a flow diagram, steps for setting up and operating a countdown installation object of the invention,

FIG. 7 represents a mechanical interface between a vehicle and a compressor, FIG. 8 illustrates the components of an interconnection module in a complete mobile reverse installation,

FIG. 9 represents changes in flow and pressure during the flow regulation of the operation of the reverse installation,

FIG. 10 represents changes in flow rate and pressure during pressure regulation of the operation of the reverse installation and

Figure 11 shows a reverse installation of the subject of the invention, mounted on a vehicle.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

FIG. 1 schematically represents the principle of a reverse installation known in the prior art. The back-up installation has a set of technical functions allowing the creation of a gas flow by controlling the operating conditions specific to a transport network 10 and to a distribution network 15. These functions include:

the treatment and control 19 of the conformity of the quality of the gas to the technical prescriptions of the transport operator,

counting 20 of the quantities transferred,

compression of the gas coming from the distribution network 15, by at least one compressor 21, these are generally compressors with an electric motor and with pistons, with two or three stages of compression,

regulation 24 of pressure or flow,

filtration 22, upstream and downstream,

management 18 of the stable operation of the distribution network,

security organs 26 and

steering tools 24 and monitoring the installation of countdowns. These different functions are described below. In addition, there are utilities (electrical sources, communication network, etc.) necessary for running an industrial installation. The back-up installation is dimensioned taking into account:

the operating pressure of the transmission network 10 and that of the distribution network 15. The first must be between 30 and 60 bars on the regional network and can reach 85 bars on the main network. The second is of the order of 4 to 19 bars on MPC networks (Medium Pressure Network type C, i.e. a pressure between 4 and 25 bars) and less than 4 bars on MPB networks (Medium Pressure Network type B, i.e. a pressure between 50 millibars and 4 bars), of the maximum production capacity of biomethane producers 17 likely to inject biomethane into the distribution network 15, capacity which varies from a few tens of Nm ³ / h for the smallest units, at several hundred Nm ³ / h for the largest,

the consumption of consumers 16 on the distribution network 15, in particular the minimum consumption and

the ability of the distribution network 15 to absorb pressure variations (volume of water).

All of this data makes it possible to determine the maximum flow rate of the reverse installation and to estimate its operating time. This duration can vary, depending on the case, from occasional operation (10 to 15% of the time) to quasi-permanent operation. This exercise must also integrate the fact that the producers' installations 17 are not put into service simultaneously but over the years.

Regarding the analysis 19 of gas compliance, differences exist between the gas quality specifications applied to the transmission 10 and distribution 15 networks, due to the different operating pressures, infrastructure, materials, uses and interfaces with underground storage. The specifications of the transport networks 10 are generally more restrictive than those of the distribution networks 10. Thus, to guarantee that the installation of gas back-flows from the distribution network 15 to the transport network 10 fits into operational operation of the transport network 10, the following provisions are provided:

a dehydration unit 29 upstream of the compression 21, to reduce the risk of condensation on the high pressure transport network, formation of hydrates and corrosion, optionally, a laboratory for analysis of the combustion parameters ( Wobbe index, calorific value and gas density) to inject inject the readings into the energy operator's system for determining the energies.

At the discretion of the transport operator, the analysis of other contents of compounds (CO2, H2O, THT, etc.) is optional and is only carried out if there is a proven risk of contamination of the transport 10 (example: reverse of a biomethane with a high CO2 content without possibility of dilution on the distribution networks 15 and transport 10, or operated at a very high pressure).

Regarding gas metering 20, the countdown installation is equipped with a metering chain consisting of a meter and a device for determining local or regional energy in accordance with legal metrology. With regard to gas compression, the compression unit makes it possible to compress the surplus production of biomethane to the operating pressure of the transmission network 10. Depending on economic criteria and availability of the installation, several configurations are possible, by example a compressor 21 achieving 100% of the maximum need for countdown, two compressors 21 each achieving 100% of the need for maximum countdown where two compressors 21 each making 50% of the need for maximum countdown.

The configuration is chosen by studying the various advantages and disadvantages in terms of cost, availability, size, and the possibility of upgrading the compression unit. The suction pressure to be considered is the operating pressure of the distribution network 15, which depends in particular on the injection pressures of the biomethane producers 17. The construction pressure at the discharge to be considered is the maximum operating pressure ("PMS") ) of the transport network, for example 67.7 bars. To ensure start-up, the anti-pumping protection of each compressor 21 (except piston compressor) or stabilized recycling operation, a recycling circuit 27 provided with a valve 28 can be provided. The recycling circuit expands gas at the second pressure and injects it upstream or at the inlet of the compressor when at least one compressor is put into operation, under the control of the controller 25.

Each compressor 21 can be sealed with oil or with dry packing. In the first case, certain filtration arrangements are put in place (see below).

An automaton 25 performs the piloting functions 24, control of each compressor and regulation and stability 18 of the network 15. It is noted that, throughout the description, the term “the automaton” means an automaton or a computer system or a set of automatons and / or computer systems (for example one automaton per function).

Concerning regulation, the evolution of the pressure of the distribution network 15 near the back-up installation is correlated to the gas flow rate passing through the back-up installation. These changes are the result of the dynamic operation of gas consumption on the distribution network 15, of the capacities injected with biomethane by the producers 17 and of the operation of the delivery installation, via a valve 14, and countdown . We therefore integrate the possibilities of adapting the operating range of the suction pressure of the reverse installation, as well as a regulation of the compressors 21 which can anticipate the stresses exerted on the distribution network 15, according to the configurations encountered. This is a difference with non-reverse delivery stations, for which the pressure is regulated at the delivery point so as to be fixed, regardless of consumption by consumers 16. Consequently, the regulation mode (pressure or flow) of the reverse flow to the transport network 10 is adapted to the proper functioning of the reverse installation.

According to the specifications of the compressors and to avoid their deterioration or due to the constraints linked to the operation of the transport network 10, filtration is provided in the gas quality compliance function, upstream of the compression to recover any liquids and dust contained in the gas from the distribution network 15. In addition, in the case of a compressor 21 with oil tightness, a coalescer filter 22 is installed at the outlet of compressor 21, for example with a manual purge and a visual level.

A cooling system 23 cools all or part of the compressed gas to maintain the downstream temperature, towards the transport network 10, at a value below 55 ° C (equipment certification temperature). To ensure the functioning of the cooling system 23, it is dimensioned from relevant ambient temperature values according to the weather histories.

The delivery station 12 is an installation, located at the downstream end of the transport network that allows the delivery of natural gas according to the needs expressed by the customer (pressure, flow, temperature ...). It is therefore a gas expansion interface from the transport network 10 to the distribution network 15 or to certain industrial installations. The delivery station 12 therefore incorporates pressure reducing valves to reduce the pressure to adapt to the conditions imposed by the downstream.

To avoid phenomena of instability, the reverse installation must not operate simultaneously with the expansion and delivery station 12 from the transport network 10 to the distribution network 15. Limit values for starting and stopping the installation of countdowns are fixed accordingly and each automaton 25 of an installation combining detent 12 and countdown is adapted so as to prohibit the simultaneity of these two functions. Back-up installations, during their start-up, operation and shutdown phase, limit disturbances in the upstream network (distribution 15) and the downstream network (transport 10), in particular by avoiding triggering safety devices under pressure at the delivery station 12. The following parameters are taken into account:

number of start and stop cycles of each compressor 21 and its compatibility with the recommendations of the supplier of compressor 21,

starting and stopping each compressor 21 by a routine, following a time delay,

the use of a buffer volume (not shown) upstream of each compressor 21, to dampen the pressure and flow variations of the distribution network 15.

A control and supervision function performed by the controller 25 makes it possible to obtain: an automatic operating mode,

a visualization / supervision of the operation of the countdown installation and the start of the countdown installation.

Data logging is performed to certify operating conditions.

In the event of an emergency, the back-up installation is isolated from the distribution network 15, by closing the valve 14. An "emergency stop" function makes it possible to stop and secure the back-up installation. The reverse installation is also fitted with pressure and temperature safety devices 26. There is no automatic venting unless safety studies contraindicate it. The back-up installation is equipped with fire and gas detection systems 26. A means of protection against overflow is provided to protect the devices, in the form of a physical organ such as a restriction orifice or by the 'through an automation.

It is noted that the flow rate of a reverse can vary from a few hundred to a few thousand Nm ³ / h depending on the case. FIG. 2 represents a particular embodiment of a scalable countdown installation 30 which is the subject of the invention. We find there the functions illustrated in figure 1, grouped in modules:

the module 37 groups together the compression 21, filtration 22, cooling 23 and recycling 27 and 28 functions,

the module 31 groups together the security 26, steering 24 and network stability 18 functions,

module 32 groups together the functions for verifying conformity of the quality of the gas 19 and metering 20 and

the module 33 includes the dehydration function 29.

Two modules are added to this set of modules:

a module 34 comprises the utility functions, in particular of electrical supply and a module 35 comprises a buffer tank for storing gas coming from the distribution network upstream of the compression and thus limiting the transient effects during the initiation of the compression.

The relationships of module 34 with the other modules are not shown in FIG. 2, for the sake of clarity. Note, however, that the module 34 supplies electrical energy to all the other modules that consume it.

The six different modules thus group together the components of the same functionality of a reverse installation:

the compression module 37 for the gas compression function in the event of failure of the fixed compressor. The compressor is either driven by the engine of the truck that transports or tows it, or driven by an electric motor powered by the power supply module or the electrical network of the existing site. To be able to adapt to a wide range of flow rates, it is possible to connect several compression modules in parallel via an interconnection module,

the automation module 31 containing a programmable automaton in order to acquire all the data necessary for monitoring the various functional modules, with a man-machine interface enabling the status of the modules to be viewed and orders to be placed when the countdown is in operation in manual mode,

the instrumentation module 32 containing various O2, H2O, CO2 and THT gas analyzers as well as a transaction type counting unit. This module also contains a filter allowing the separation of solid and liquid particles potentially entrained by natural gas from the distribution network,

the dehydration module 33 (optional use) to manage the different water contents between the distribution and transport networks,

the electrical supply module 34 containing a generator, to supply the compression module, and an uninterrupted supply system (batteries with their charger and possibly inverter) to supply the control-command of the various modules and the large volume buffer tank module 35 (optional use) to o guarantee a sufficiently large volume at the suction of the compression, in order to respect the start and stop times of the compression group and o have a sufficient volume to absorb overpressures in the event of an incident

Apart from the large volume buffer tank module 35, each of these modules is preferably integrated in an autonomous container, as illustrated in FIG. 3.

The six modules can be transported by a truck or a truck trailer and can be interconnected so that they can form a complete mobile reverse installation. Each module can also be connected to a fixed countdown installation to ensure its dedicated functionality in the event of a fixed equipment failure. Each module has its own safety devices and its own automaton, which makes it autonomous and independent of the other modules, apart from the overall control of the reverse installation, energy and gas supply, if applicable.

This makes it easy to put into operation a fully mobile back-up installation as well as the evolution of the capacities of a fixed or mobile back-up installation. Indeed, it is enough to connect the different modules or to add a module to an existing installation.

In FIG. 3, connected to the transport network 10 and to the distribution network 15, there is an interconnection module 36 which distributes the gas between the compression modules 37. The interconnection module 36 comprises valves and a interconnection grid (see figure 8), to connect the different modules. The interconnection module 36 is connected to networks 10 and 15 via an existing flange with a quick connector. For example, the interconnection module 36 has flexible connectors.

In FIG. 4, the various modules illustrated in FIG. 2 are observed, in the form of standard containers allowing their transport on trucks or trailers.

In FIG. 5, a reverse installation 40 is observed, which comprises a fixed part in a building, in particular a slab 41 for supporting the various systems, a cabinet 42 comprising the automaton 33, at least one compressor 43, and a line 44 for electrical and computer connection of the various systems provided with sensors and actuators (in particular valves).

In the embodiment illustrated in FIG. 5, the countdown installation 40 comprises at least one reception space, or location, 49 dedicated for an additional compressor near a free interface of the distribution unit and near a free interface of the collection unit. The implementation of each additional compressor is thus facilitated.

The reception space 49 is provided with at least one connector 83 for gas inlet at the first pressure, at least one connector 81 for gas outlet at the second pressure and at least one connector for energy supply 82 (gas from the distribution network 15 or electricity) of each additional mobile compressor 37. This connector 82 can supply an electric or thermal motor for actuating the additional mobile compressor 37 or a generator of a vehicle with gas at the first press, generator supplying an electric motor actuating the additional mobile compressor 37.

The pipes and the electrical supplies (not shown) are dimensioned for the simultaneous operation of each fixed compressor 43 and each mobile compressor additional 37. Thus, the reverse installation 40 can accommodate each additional compressor without the latter having to be associated with a supply and / or additional pipes.

FIG. 5 shows the installation of reverse 40 after connection of a mobile additional compressor module 37 mounted on a vehicle 47 (here a truck or a trailer) and connected to the distribution network 15 by a connector 48.

Thanks to the mobility of the additional compressor 37, during a temporary increase in the capacity needs of the back-up installation 40 (transient failure or overcapacity of biogas producers, transient drop in consumption by gas consumers), it is quickly added and easily the additional mobile compressor 37 to the countdown installation 40. And it is removed once this temporary increase is completed.

Because the compressor module 37 is mounted on a vehicle 47 and, preferably integrated in a standard container, the transport of the compressor module 37 is facilitated.

In embodiments, the compressor module 37 is mechanically actuated by a motor of the vehicle 47, as shown with reference to FIG. 7. For this purpose, a mechanical connection, for example with cardan shafts, connects a shaft of the vehicle engine 47 , for example its single engine, to a compressor shaft. Preferably, the motor actuating the additional compressor 37 is an electric motor or a gas engine using gas from the lower pressure pipeline of the distribution network 15.

In embodiments, at least one additional mobile compressor 37 is supplied with electrical energy by a generator mounted on the vehicle 47, preferably operating with gas from the lower pressure pipeline of the distribution network 15. Thus, the actuation of the compressor 37 does not require oversizing of the energy supply of the back-up installation 40, compared with the supply of the only fixed compressors 43.

In the embodiment illustrated in FIG. 5, the countdown installation 40 comprises:

at least the fixed compressor 43 between the gas distribution network 15 at a first pressure, and the gas transport network 10 at the second pressure and

the reception space 49 of at least one additional compressor, space provided with at least one connector 83 for gas inlet at the first pressure, for at least one connector 81 for gas outlet at the second pressure and, optionally, at least one energy supply connector 82 (gas from the distribution network 15 or electricity) of the additional mobile compressor 37,

the distribution unit 31 for distributing gas from the gas network at the first pressure to each fixed compressor and to the gas inlet connector at the first pressure for at least one additional mobile compressor 37 and

the collection unit 32 for collecting the gas coming from each fixed compressor and from the gas outlet connector at the second pressure for each additional mobile compressor 37. The automaton 33 for controlling the operation of each fixed compressor and of each additional mobile compressor 37, is configured to detect the fixed and additional operational compressors, to determine the compression capacity of the operational compressors and to control the operation of each fixed compressor and each additional compressor according to the compression capacity of the fixed and additional operational compressors.

In FIG. 5, the reception space 49 of at least one additional compressor is configured to accommodate a vehicle carrying at least one additional compressor. The installation 40 is configured so that the vehicle 47 accesses while driving from outside the installation to the reception space 49.

The modular nature of the mobile countdown installation object of the invention allows the transmission system operator to have to transport only the functionalities broken down in the fixed countdown installation. Interventions are therefore simpler and maintenance of the system can be carried out on part of the equipment, leaving the other parts functional.

FIG. 6 shows the steps of a method for putting into operation a mobile countdown installation object of the invention.

During a step 51, each module is transported to the place of installation, for example near a gas expansion station of the transport network and supply of expanded gas to a distribution network.

A mobile back-up installation comprises at least the automation module 31, the interconnection module 36 and a compressor module 37. The electric power supply module 34 is preferred, but it can be replaced by a generator associated with a motor. vehicle, as shown opposite Figure 7.

During a step 52, the modules are connected, to each other by means of the interconnection module 36, and to the pipes of the transport and distribution networks 15. The modules consuming electricity are also electrically connected. electrical energy and by computer the modules comprising sensors and / or actuators, for example valves.

During a step 53, the controller detects the presence of the additional compressor and its compression capacity. This detection can be automatic, for example by detecting the electrical connection between the controller and the compressor motor, or manual, the installation of the compressor being declared by an operator on a user interface of the controller.

During a step 54, the automaton defines the configuration of the operation of the mobile countdown installation as a function of the operational compression capacity (that is to say including the compressor module but without taking the compressors into account broken down or stopped, for example for maintenance or update). The operational configuration essentially consists of setting:

pressure limit values and other physical quantities measured by sensors integrated into the various devices present in the installation and

optionally, values of actuation parameters of valves and other devices, such as delay times or evolution curves. During a step 55, the automaton controls the putting into operation of the reverse installation.

During a step 56, the automaton receives physical quantities sensed by the sensors of the reverse installation, in particular the value of the pressure at the inlet of each compressor.

During a step 57, the controller controls the recycling circuit as a function of the operational compression capacity. Indeed, the unitary or joint start-up of compressors causes a pressure spike and can cause problems of maximum working pressure ("PMS") and minimum pressure (2.5 bar). These risks are avoided by defining limit values and the recycling circuit (re-expansion) is implemented to produce a starting ramp and break the transient.

During a step 58, the automaton receives physical quantities sensed by the sensors of the reverse installation, in particular the value of the pressure at the inlet of each compressor.

During a step 59, the automaton controls the stationary operation of the reverse installation, until the compressors stop (see FIGS. 9 and 10). Then we return to step 56 for the next phase of starting up at least one compressor.

As illustrated in FIG. 7, the compressor 37 and the power supply module can be driven by an autonomous motor or the engine of a vehicle, in particular a truck or a tractor. In the embodiment illustrated in FIG. 7, the power shaft of a tractor 60 drives the mobile compressor 37 and supplies the electricity necessary for the reverse installation.

Preferably, an anti-noise screen (20 dB) is provided and use of the tractor engine at medium power, to reduce noise pollution.

The power supply module 34 driven by a vehicle engine is, for example of the type described in international PCT application WO2013182824.

Mechanical actuation of the compression module 37 can also be achieved by the engine of this vehicle.

As can be seen in FIG. 7, removable connection means are arranged on the compression module 37. These removable connection means are configured to temporarily connect the connection axis of a compressor to a power take-off 61 of a vehicle 60. The rotation of the PTO causes the rotation of the connecting axis and therefore that of the compressor shaft 37, which allows the compressor 37 to operate. Of course, these removable connection means make it possible to quickly disconnect the compression module 37 from the PTO of the vehicle 60.

As illustrated in FIG. 7, the removable connection means consist of a transmission shaft fitted with cardan shafts and a torque limiter. A first gimbal is assembled to the link pin and a second gimbal is assembled to the vehicle PTO. These provisions have the advantage of being able to easily transmit the rotation of the PTO of the vehicle to the connecting axis even in the event of offset between these elements.

In embodiments, servo means include, for each vehicle, a potentiometer and a servomotor or equivalent, which acts on the variation of the potentiometer as a function of a set value calculated by the servo means, the potentiometer being configured to be electrically connected to a vehicle computer making it possible to control the speed of rotation of a vehicle engine. In an alternative embodiment, the servo means comprise, for each vehicle, an actuation system configured to mechanically activate a vehicle speed pedal configured to modify the speed of rotation of an engine of said vehicle.

Thus, the PLC module 31 is connected by means of a servo cable to an adjustment device which acts on the vehicle engine, so as to regulate the speed of rotation of the engine and thus, to regulate the speed and, therefore, the frequency of rotation of the PTO, which makes it possible to regulate the compression produced by the compression module 37.

The PLC module 31 is therefore programmed to transmit a setpoint to the adjustment device enabling the motor to be controlled. In one embodiment, not illustrated in detail in the figures, this adjustment device consists of a servomotor or an equivalent system, powered by an external electrical source, such as a battery, and a connected potentiometer to the servomotor.

This servomotor allows you to modify the potentiometer setting in order to change the value of its resistance. This servomotor is controlled by the alternator management module. This potentiometer is connected by a connection cable to a computer arranged on the vehicle, the computer making it possible to modify the speed of rotation of the vehicle engine as a function of the adjustment of the resistance of the potentiometer. The arrangement of such a computer on a vehicle is known to those skilled in the art of the vehicle field.

In an alternative embodiment, this adjustment device consists of an actuation system which comprises a support pillar comprising at its lower end a magnetic suction cup, or a forestay fixed in the cabin or a sufficiently heavy support, allowing assembly temporary actuation system on the vehicle floor. A control cylinder is mounted in pivot connection at its rear end, on the support pillar. The piston of the control jack has its end mounted in pivot connection on a pilot lever, one of the ends of which is mounted in pivot connection at the lower end of the support pillar. The second end of the pilot lever is in contact with a vehicle pedal allowing the engine speed and therefore the PTO speed to be changed. The automation module therefore allows, via the servo cable, to control the control cylinder in order to regulate the speed of the motor.

In a variant design of the removable connection means between the vehicle and the compressor module 37, these may consist of a transmission mechanism by agricultural gimbal configured to be connected directly or indirectly via a limiter torque to a drive axle of a vehicle such as a truck, car or tractor, for example. It may for example be two rollers capable of receiving a wheel of the vehicle. The rotation of the wheel causes that of the rollers which mesh and cause a power take-off connected to the compressor shaft by a cardan type transmission. It is also possible to provide a part configured to be engaged on the studs or on the locking nuts of the wheel of a vehicle and a vehicle lifting system making it possible to lift the driving wheels, to position them out of contact with the ground, said part constituting a power take-off which is connected to the compressor shaft by a cardan type transmission.

In FIG. 8, a mobile reverse installation 30 is observed, between a gas transport network 10 and a gas distribution network 15. The gas coming from network 15 first circulates through the buffer tank module 35 then through the gas compliance and metering verification module 32, the dehydration module 33, a quick-coupling hose 71 and a first part 36A of the interconnection module 36. This first part 36A has inlet valves 72 , a gas suction connection manifold 73 and outlet valves 74. Flanged hoses 75 connect each outlet valve 74 to the inlet of a compressor module 37. Each outlet of a compressor module 37 is connected , by a flexible flange 76 to a second part 36B of the interconnection module 36. This second part 36B comprises inlet valves 77, a gas connection connection manifold 78 and outlet valves 79. A flexible hose at quick spot 80 connects one of the outlet valves 79 to the transport network 10.

Outside this gas circuit, the module 31 performs the safety, control (pressure or flow regulation) and network stability functions 15 and the module 34 performs the utility functions, in particular power supply .

Two types of regulation envisaged for the compressor are described below. The flow regulation means that the flow which passes through the compressor is constant when the mobile reverse installation is operating. On the other hand, it is indeed the suction pressure (for example in a medium pressure network) which triggers the start and stop of the compressor when this pressure reaches limit values fixed during step 54. FIG. 9 represents a example of evolution of the pressure 90 upstream of the compressor and of the flow rate 91 of the compressor, in a case where the limit value of the compressor start pressure is 4.2 bars and where the limit value of the compressor stop pressure is 2.5 bars. When the pressure decreases between these two limit values during compressor operation, the controller regulates compressor operation to have a constant flow of 700 Nm ³ / h.

In the case of pressure regulation, the flow which passes through the mobile back-up installation changes so that the suction pressure (for example in a medium pressure network) remains constant. FIG. 10 illustrates an example of evolution of the pressure 90 upstream of the compressor and of the flow rate 91 of the compressor with a set pressure value upstream of the compressor of 4 bars, as a function of the flow rate 92 of gas consumed by consumers on the distribution network, the flow 93 of gas injected by biomethane producers on the distribution network. We also observe, in Figure 10, the flow 94 of gas supplied by the transport network.

It can be seen, in FIG. 10, that as soon as the flow of consumption on the distribution network is lower than the flow of biomethane injection, the delivery station stops injecting gas from the transport network and the PLC regulates the compressor so that the pressure of the distribution network is constant whatever the variations in consumption on the distribution network.

In the case of the presence of two compressors, a first compressor ensures the operation of the reverse installation up to its operating limit. If needed, the automaton controls the operation of a second compressor to complete the flow of gas passing through the back-up installation.

In embodiments, the compressor is driven by a gas engine from which all the hydraulic power necessary to supply the auxiliaries is taken. The installation is then completely independent and does not require connection to the electrical network.

In embodiments in which the reverse installation is transported on a truck or a trailer, as in FIG. 11, preferably air coolers are placed at the rear and not above the vehicle. Installation operations are thus reduced since there is no crane cooling operation. The countdown system can be removed as it is on site for long-term use or the countdown system can remain mounted on the truck or trailer during operation.

The front electrical cabinet is isolated from the rest of the facility and includes a 3G industrial router for telecommunications.

A mobile analysis laboratory, including a common chromatograph for measuring THT and gas components and a hygrometer, for example ceramic, is integrated into the countdown installation. The countdown installation can also integrate a dehydrating skid and a volumetric counter for billing.

Several back-up installations can be installed in parallel, in particular for cases of low gas consumption and significant injection of biogas on the distribution network.

Functional specifications of the mobile countdown installation:

F1: Allow the transmission of a finite volume flow of gas from the medium pressure distribution network to the high pressure transport network during off-peak periods,

F2: Guarantee the complete autonomy of the mobile countdown installation,

F3: Guarantee that there is no variation in pressure in the distribution network,

F4: Respect the network conformity specifications,

F5: Respect the network quality specifications.

Note that the admissible water content on the GRT GAZ and GRDF network are different. Indeed, despite the fact that the two networks have the same dew point, the absolute humidity rate (expressed in mg. Nm ^{~ 3} ) varies with pressure. The admissible contents of CO2 and O2 are also different. The specifications are summarized in the table below:

Transport network Distribution network

O2 <0.7% <0.75%

H2O <53.2 mg.Nrrr ³ <800 mg.Nrrr ³

CO2 <2.5% <3.5%

In addition, the outlet temperature of the mobile countdown installation must not be lower than the recommendations applicable to the transport network. The transaction metering covers the normal compressed flow, expressed in energy (kWK), from the PCS. If the pressure of the medium pressure network tolerates a large pressure range (a priori rather 8 barG or 20 barG networks), regulation can be done by flow. In this case, the pressure on the medium pressure network is not regulated but limited between a minimum and maximum value. For the compressor this means operation where the engine speed is adapted for a fixed volume flow. If the distribution network does not tolerate pressure variation, opt for pressure regulation. In all cases, it is considered that the pressure of the transport network is regulated elsewhere.

Two solutions are possible. In the case where a fixed speed is desired for the compressor, in order to remain in particular in its optimal operating range, a recycling device is used which makes it possible to guarantee a high pressure (at the outlet of the compressor) greater than the pressure of the transport network. The normal flow to the compressor is constant. The pressure of the distribution network is regulated by an overflow valve. In the event that the compressor accepts a variable speed, the pressure will be regulated by the engine speed of the engine which actuates the compressor. This solution requires the use of a frequency converter which controls the compressor motor.

The compressor can be a horizontal reciprocating compressor, more reliable and less fragile than a "V" compressor. With this type of compressor, pressure regulation by variation of engine speed can easily be envisaged. This engine can be an engine consuming gas taken from the distribution network at the first pressure.

Reciprocating compressors allow very high compression rates and great flexibility in their use. A reciprocating compressor can start and operate at a flow rate close to zero. Horizontal reciprocating compressors have, for example, pistons mounted in tandem. The compression chamber has a smaller area which increases the compression ratio. A double-acting piston compresses the gas back and forth. The compression chambers are of equal area. This configuration is more complex since the segments must be sealed on both sides. Such an arrangement of pistons makes it possible to increase the compactness of a compressor by multiplying the compression chambers.

Low capacity compressors can be air cooled with a fan mounted directly on the shaft. For larger capacity compressors, the gas is cooled in intermediate exchangers and a brine circuit passes through the cylinder liners to cool the gas also during compression.

It is preferable to winnow in series after the compressor to facilitate its start-up. Indeed, in the absence of winnowing, the engine should overcome the network back pressure at a reduced speed and under these conditions the engine torque would skyrocket. Whichever solution is chosen for regulating the network, an overflow valve or a valve downstream of the compressor is recommended for starting the machine.

Regarding the engine, a gas engine ensures the presence of an energy source regardless of the location considered. The motors are industrial type.

Several alarms are implemented on the countdown installation:

THT content below the mandatory threshold downstream of the dehydrator,

Abnormally high water content upstream of the dehydrator, Water content above the threshold recommended on the transport network downstream of the dehydrator,

Upstream gas quality.

Transaction counting is done in energy. This energy is the product of the PCS (expressed in kWh / Nm ³ ) by the normalized volume flow.

The instruments for measuring the volume flow do not return the standardized measurement. To make the link, we will use the relationship:

Where the index (/ represents the conditions at the reference state and index 7 the conditions at the aspiration.

Correlation calorimeters can only work for an already known type of gas (natural gas or biomethane), and must be preset accordingly. Indeed, the algorithm which deduces the PCS from the measurement of the conductivity and a calibration curve cannot work over a wide range of composition covering natural gas and biomethane.

However, in the place where the mobile back-up installation is used, the gas is a mixture of natural gas and biomethane, so it is not possible to predict its composition. Preferably, the mobile countdown installation includes a means of obtaining the composition of the gas. The gas composition is analyzed by a chromatograph.

The device can be composed of a pneumatic analysis box of a separate electrical box including the electronic components for data processing. The electrical box can be moved to the electrical cabinet while the pneumatic analysis box is integrated in an air-conditioned laboratory protected from vibrations, mounted on the mobile countdown installation.

Integrating and using a chromatograph on a mobile device is complex. To get rid of the problem, we can deport the analysis:

At the trigger station or the countdown station if it is nearby and is equipped where

In the laboratory, a posteriori.

In the latter case, the trailer of the mobile reverse installation is equipped with a bottle storage system. The gas is withdrawn at regular time intervals by an automated system (pneumatic valves).

Regarding the measurement of THT, a single analyzer equips the mobile countdown installation, downstream of the dehydrator.

The THT (TetraHydroThiophene) gas composition and content analyzer is preferably a single machine. This solution is currently being tested with a view to obtaining approval for the network. Preferably, the mobile countdown installation includes an air-conditioned laboratory protected from shocks and vibrations, laboratory which includes at least one chromatograph

Preferably, a quartz crystal hygrometer or a ceramic sensor is used.

Each compression stage is equipped with a valve. If these valves are connected to the distribution network, account is taken of the influence of the back pressure on the calculation of the coefficient of debt. The setting of the discharge valves is PMS (67.7) + 6% maximum. The calibration of the suction valves is PS + 6%.

The back-up installation includes a fire station, with detector and extinguisher, as well as gas detection. The electrical cabinet is isolated from the compressor by a wall comprising watertight bulkheads.

The architecture of a mobile reverse installation mounted on a vehicle 100 is shown in Figure 1 1. Vehicle 100 is a fitted, containerized, pre-assembled truck or trailer comprising all the functionalities (motor-compressor and its auxiliaries, cooling circuit with fan, transactional metering, instrumentation and industrial computer).

The gas engine is powered by the lower pressure gas network, in order to avoid relaxing the gas which is sought to be compressed by means of the countdown. The rear part 101 comprises the air coolers. The next part, 102, includes the gas engine and an air filter. The compressor is located in part 103, with its auxiliaries. The front portion 104 includes the other functions of the mobile countdown installation, in particular gas analysis, metering, dehydration, remote communication, fire panel and control automaton).

In this embodiment, there is a direct motor-compressor coupling, an isolated electrical cabinet (in part 104), a water cooling circuit, a primary energy extraction on the compressor. via a hydraulic system for supplying the main consumers (in particular fan and pumps), a battery linked to the vehicle engine and to the compressor motor for supplying electronic auxiliaries (in particular sensors and electrical cabinets), fan included . The main source of energy is natural gas. The consumer list includes compressor auxiliaries, fans, air cooler, compressor water pump, engine auxiliaries, lubricating oil pump, electric oil heater, control-command, alternator 24 volts and control systems.

Small consumers (including control cabinet, lighting, instrumentation, metering and gas quality) are powered by a 24V alternator connected to a battery. This battery is powered by the gas engine. It is also connected to the engine of the truck so that the control bodies are operational immediately after transport.

The cooling circuit, the fan and the engine lubrication are supplied by a hydraulic system whose power is extracted directly from the engine.

The pressure regulation is done via the servomotors of the regulators. The service valves are manual because there is no need to isolate the compressor from the network when the machine is stopped. The installation does not have actuators which reduces consumption. In embodiments with actuators, a hydraulic or pneumatic supply is preferred. Indeed, these actuators do not consume anything when stopped (unlike electric actuators which maintain a current at their terminals to fight against the closing of the spring).

Preferably, the compressor allows the number of compression stages to be automatically adapted to the input conditions. When the upstream pressure is high, all stages of the compressor are supplied simultaneously to increase the flow rate. Conversely, when the upstream pressure is lower and the required compression ratio is higher, the compression is stepped with possible intermediate cooling. This system improves the adaptation of the compressor to operating conditions. It avoids the use of a pre-expansion valve (which lowers the overall performance of the system) over a wider pressure range. With this solution, the compressor can quickly lower the pressure of the distribution network (if it is very high) while in the first operating mode. Once the pressure has dropped to a certain predetermined value, the compressor goes into the second operating mode, to ensure the required compression ratio.

Claims

1. Reverse installation (30, 40), characterized in that it comprises:

modules (31 to 35 and 37) comprising the following functions:

o at least one compressor to compress gas,

o at least one filter to filter the gas circulating in the compressor; and a module (36, 36A, 36B) for interconnection between the other modules and with a gas network (15) at a first pressure and a gas network (10) at a second pressure greater than the first pressure;

2. countdown installation (30, 40) according to claim 1, in which all the modules (31 to 35, 37) of the countdown installation are mobile, configured to be transported, fully and in working order by removable connection. to the interconnection module and to an energy source, on a single vehicle.

3. Reverse installation (30, 40) according to one of claims 1 or 2, which comprises a mobile autonomous electrical power source.

4. Reverse installation (30, 40) according to claim 3, wherein the mobile electrical power source is a generator operated by a vehicle engine.

5. Reverse installation (30, 40) according to one of claims 3 or 4, wherein the electrical power source is a motor supplied with gas at the first pressure.

6. Reverse installation (30, 40) according to one of claims 1 to 5, in which at least one module comprises a gas detector and / or a fire detector.

7. countdown installation (30, 40) according to one of claims 1 to 6, in which at least one compressor is mechanically actuated by a vehicle engine (47).

8. Reverse installation (30, 40) according to one of claims 1 to 7, in which the interconnection module (36) comprises:

a mobile distribution unit (36A) for distributing gas from a gas network at a first pressure to several modules (31 to 35, 37) by an interface and a mobile collection unit (36B) for collecting gas from of each said module to a second interface.

9. Reverse installation (30, 40) according to one of claims 1 to 8, in which the automaton is configured to control the operation of a plurality of compressors as a function of the compression capacity of the operational compressors.

10. Reverse installation (30, 40) according to one of claims 1 to 9, which further comprises at least one recycling circuit (27, 28) provided with a valve (28), configured to relax the gas at the outlet of a compressor and inject it upstream or at the inlet of said compressor when at least one compressor is put into operation, the automaton being configured to control the operation of the valve of the recycling circuit as a function of the compression capacity of operational compressors which are put into operation jointly.

1 1. Countdown installation (30, 40) according to one of Claims 1 to 10, in which at least one module (31 to 35, 37) of the countdown installation is integrated in a standard container.

12. Reverse installation (30, 40) according to one of claims 1 to 1 1, which comprises a mobile analysis laboratory air-conditioned and protected from shocks and vibrations, laboratory comprising a common chromatograph for the measurement of THT and the composition some gas.

13. Reverse installation (30, 40) according to one of claims 1 to 12, which comprises a correlation calorimeter implementing the composition of the gas obtained by a chromatograph.

14. countdown installation (30, 40) according to one of claims 1 to 13, which comprises a hygrometer, for example ceramic.

15. Reverse installation (30, 40) according to one of claims 1 to 14, which comprises a dehydrating skid and a volumetric counter.

16. countdown installation (30, 40) according to one of claims 1 to 15, which comprises a means of winnowing in series downstream of at least one compressor.

17. Reverse installation (30, 40) according to one of claims 1 to 16, which comprises an outlet in series, downstream of at least one compressor.

18. Reverse installation (30, 40) according to one of claims 1 to 17, which comprises a gas storage system in the bottle and a means of taking gas at different times, for example with pneumatic valves.

19. countdown installation (30, 40) according to one of claims 1 to 18, which comprises a fire station, with detector and fire extinguisher, as well as a gas detection means.

20. Reverse installation (30, 40) according to one of claims 1 to 19, which comprises an electrical cabinet isolated from each compressor by a wall comprising watertight bulkheads.