EP3807569B1 - Mobile backfeeding installation - Google Patents

Description

TECHNICAL AREA

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

STATE OF THE ART

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

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 under development.

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 outlet. Indeed, the consumption of domestic customers varies on average from 1 to 10 between winter and summer on public distribution. The injection of biomethane is initially only possible if it is done at a flow rate lower than the minimum flow rate 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 the hot seasons. This situation limits the development of the biomethane production sector by the congestion of the natural gas distribution networks. Several solutions have been identified to solve this problem: the meshing 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 production during low consumption seasons, the development of gas uses (for mobility, in particular), as well as the construction of back-up stations between gas distribution and transport networks natural.

Backhaul facilities are thus one of the solutions identified for developing biomethane injection capacities. These facilities make it possible to export excess biomethane from a distribution network to the transport network, by compressing them and reinjecting them into this transport network in order to benefit from its greater gas storage capacity. Thus, producers would no longer have to limit their production and the profitability of their projects would be more easily ensured. The back-up station is a structure of the transport operator allowing the transfer of gas from the distribution network to the transport network having a large storage capacity, via a gas compressor station. The countdown station can be located either near the regulator station, or at another location where the transmission and distribution networks intersect.

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

For economic reasons, some reverses are only equipped with a compressor ensuring 100% of the flow. These countdowns therefore do not guarantee normal operation in the event of failure of the compressor alone. But the installation of a second compressor ensuring 100% of the flow to provide backup in the event of failure of a fixed reverse is a costly solution. In the event of a breakdown of a backhaul station, biomethane producers can no longer supply their biomethane production. Similarly, if a new biomethane supplier is connected without prior installation of a back-up station which becomes necessary, the biomethane producers are penalized. Similarly, the need for a back-up station can be temporary or an investment in such a back-up station can be deferred, in particular while waiting for other connections of biomethane producers, with the same consequences for this sector. .

Furthermore, the configurations of the distribution networks change, in particular when a biogas supplier is connected to them and injects biogas into them or disconnects from them. At the same time, gas consumption on this distribution network may increase or decrease, for example during the installation of a factory or a large consumer area or during its shutdown. The reverse capacity can therefore find itself, temporarily or definitively, excess or insufficient.

More generally, the existing reverse installations do not allow their sizing to change according to need.

Current backhauls are fixed installations where the compressors are placed in buildings. The current countdowns therefore do not allow rapid and flexible intervention on the networks.

We know the document FROM 10 2009 038 128 which discloses a reverse installation positioned between two gas networks of different pressure.

DISCLOSURE OF THE INVENTION

• des modules comportant les fonctions suivantes :
  • ∘ au moins un compresseur pour comprimer du gaz,
  • ∘ un automate de commande de fonctionnement d'au moins un compresseur,
  • ∘ au moins un capteur de conformité de qualité du gaz circulant dans le compresseur,
  • ∘ au moins un compteur pour compter un débit de gaz circulant dans le compresseur et
  • ∘ au moins un filtre pour filtrer le gaz circulant dans le compresseur ; et
• un module d'interconnexion entre les autres modules et avec un réseau de gaz à une première pression et un réseau de gaz à une deuxième pression supérieure à la première pression ;

dans lequel au moins un de ces modules est mobile, configuré pour être transporté, intégralement et en état de fonctionnement par connexion amovible au module d'interconnexion et à une source énergétique, sur un seul véhicule.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:
  • ∘ at least one compressor to compress gas,
  • ∘ an operating control automaton for at least one compressor,
  • ∘ at least one gas quality conformity sensor circulating in the compressor,
  • ∘ at least one counter to count a flow of gas circulating in the compressor and
  • ∘ 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 higher 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 interconnect module and to a power source, on a single vehicle.

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

• assurer un secours mobile et un taux de disponibilité plus important en cas de panne d'une installation de rebours mobile déjà existante,
• offrir la possibilité de différer un investissement dans une installation de rebours fixe,
• d'offrir une solution temporaire en cas d'urgence (besoin ou retard) et
• de répondre à des besoins ponctuels ou trop faibles pour justifier un investissement sur une installation de rebours fixe. Ce qui permet donc de renforcer le développement des capacités d'injection déjà initié par les installations de rebours fixes et donc de maximiser l'accueil des projets d'injection de biométhane.

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

• provide mobile backup and a higher availability rate in the event of a breakdown of an existing mobile reverse installation,
• offer the possibility of deferring an investment in a fixed reverse installation,
• to offer a temporary solution in case of emergency (need or delay) and
• meet occasional needs or needs that are too low to justify investing in a fixed reverse installation. This therefore makes it possible to strengthen the development of injection capacities already initiated by the fixed reverse installations and therefore to maximize the reception of biomethane injection projects.

In embodiments, all the modules of the backhaul 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.

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

In some embodiments, the backhaul installation comprises a mobile autonomous electrical power source.

Thanks to these provisions, the mobile reverse 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 powered 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 electrical power source is an engine 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 security of the mobile reverse installation is ensured by at least one of the modules that it comprises.

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

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

• une unité mobile de distribution pour distribuer du gaz provenant d'un réseau de gaz à une première pression à plusieurs modules par une interface et
• une unité mobile de collecte pour collecter le gaz provenant de chaque dit module à une deuxième interface.

In embodiments,
In embodiments, the interconnect 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 gas from each said module at a second interface.

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

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

Thanks to these provisions, the evolution of the compression capacities of the reverse installation is easy. Indeed, a compressor module can easily be commissioned or removed in this installation.

In some embodiments, the reverse 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 according to 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, whatever the operational compression capacity of the compressors put into operation jointly, that is to say simultaneously or with a reduced time delay.

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

In embodiments, at least one module of the reverse 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 driven 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.

By virtue of each of these arrangements, the actuation of the compressor does not require oversizing of the electrical power supply of the reverse installation, with respect to the power supply of the stationary compressors alone.

In some embodiments, the reverse installation comprises an air-conditioned mobile analysis laboratory protected from shocks and vibrations, this laboratory comprising a common chromatograph for measuring the THT and the composition of the gas.

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

In some embodiments, the reverse 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 reverse installation comprises a hygrometer, for example ceramic.

This hygrometer being less sensitive than other types of hygrometers to vibrations, the design of the mobile back-up installation is facilitated.

In some embodiments, the reverse installation comprises a dehydration skid and a volumetric counter.

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

In some embodiments, the reverse installation comprises a backflow device in series, downstream of at least one compressor.

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

In some embodiments, the backhaul installation comprises a bottled gas storage system and a gas sampling means at different times, for example with pneumatic valves.

By virtue of these provisions, the composition of the gas can be determined in a deferred manner, which reduces the cost price of the installation, compared with the incorporation of a chromatograph.

In some embodiments, the reverse installation comprises a fire control panel, with detector and extinguisher, as well as a gas detection means.

In some embodiments, the reverse installation comprises an electrical cabinet isolated from each compressor by a wall comprising watertight bulkhead passes.

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

BRIEF DESCRIPTION OF FIGURES

• la figure 1 représente, sous forme d'un schéma bloc, une installation de rebours connue dans l'art antérieur,
• la figure 2 représente, sous forme d'un schéma bloc, une installation de rebours objet de l'invention,
• la figure 3 représente, schématiquement, l'assemblage de différents modules d'une installation de rebours objet de l'invention,
• la figure 4 représente, schématiquement, des modules d'un mode de réalisation mobile d'une installation de rebours,
• la figure 5 représente, schématiquement, une installation de rebours fixe comportant un module mobile,
• la figure 6 représente, sous forme d'un logigramme, des étapes de mise en place et fonctionnement d'une installation de rebours objet de l'invention,
• la figure 7 représente une interface mécanique entre un véhicule et un compresseur,
• la figure 8 illustre les composants d'un module d'interconnexion dans une installation de rebours mobile complète,
• la figure 9 représente des évolutions de débit et de pression lors de la régulation en débit du fonctionnement de l'installation de rebours,
• la figure 10 représente des évolutions de débit et de pression lors de la régulation en pression du fonctionnement de l'installation de rebours et
• la figure 11 représente une installation de rebours objet de l'invention, montée sur un véhicule.

Other advantages, objects and characteristics of the present invention will emerge from the description which will follow given, for an explanatory and in no way limiting purpose, with regard to the appended drawings, in which:

• there figure 1 represents, in the form of a block diagram, a reverse installation known in the prior art,
• there figure 2 represents, in the form of a block diagram, a reverse installation which is the subject of the invention,
• there picture 3 schematically represents the assembly of different modules of a reverse installation which is the subject of the invention,
• there figure 4 schematically represents modules of a mobile embodiment of a reverse installation,
• there figure 5 schematically represents a fixed reverse installation comprising a mobile module,
• there figure 6 represents, in the form of a flowchart, the steps for setting up and operating a reverse installation that is the subject of the invention,
• there figure 7 represents a mechanical interface between a vehicle and a compressor,
• there figure 8 illustrates the components of an interconnection module in a complete mobile backhaul installation,
• there figure 9 represents changes in flow and pressure during the flow regulation of the operation of the reverse installation,
• there figure 10 represents changes in flow rate and pressure during the pressure regulation of the operation of the backhaul installation and
• there figure 11 represents a reverse installation object of the invention, mounted on a vehicle.

DESCRIPTION OF EMBODIMENTS OF THE INVENTION

• le traitement et le contrôle 19 de la conformité de la qualité du gaz aux prescriptions techniques de l'opérateur de transport,
• le comptage 20 des quantités transférées,
• la compression du gaz en provenance du réseau de distribution 15, par au moins un compresseur 21, il s'agit généralement de compresseurs à moteur électrique et à pistons, avec deux ou trois étages de compression,
• la régulation 24 en pression ou en débit,
• la filtration 22, amont et aval,
• la gestion 18 de la stabilité du fonctionnement du réseau de distribution,
• les organes de sécurité 26 et
• les outils de pilotage 24 et de suivi de l'installation de rebours.

There figure 1 schematically represents the principle of a reverse installation known in the prior art. The reverse installation has a set of technical functions making it possible to create a flow of gas 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 with the technical requirements of the transport operator,
• the counting 20 of the quantities transferred,
• the 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 pistons, with two or three compression stages,
• regulation 24 in pressure or flow,
• filtration 22, upstream and downstream,
• management 18 of the stability of the operation of the distribution network,
• the security organs 26 and
• tools for piloting 24 and monitoring reverse installation.

• de la pression d'exploitation du réseau de transport 10 et de celle du réseau de distribution 15. La première doit être comprise entre 30 et 60 bars sur le réseau régional et peut atteindre 85 bars sur le réseau principal. La seconde est de l'ordre de 4 à 19 bars sur les réseaux MPC (Réseau Moyenne Pression de type C, soit une pression entre 4 et 25 bars) et inférieure à 4 bars sur les réseaux MPB (Réseau Moyenne Pression de type B, soit une pression entre 50 millibars et 4 bars),
• de la capacité maximale de production des producteurs de biométhane 17 susceptibles d'injecter du biométhane dans le réseau de distribution 15, capacité qui varie de quelques dizaines de Nm³/h pour les plus petites unités, à plusieurs centaines de Nm³/h pour les plus grosses,
• de la consommation des consommateurs 16 sur le réseau de distribution 15, notamment la consommation minimale et
• de la faculté du réseau de distribution 15 à absorber des variations de pression (volume en eau).

These different functions are described below. There are also utilities (electrical sources, communication network, etc.) necessary for running an industrial installation. The reverse installation is sized taking into account:

• the operating pressure of the transport 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 around 4 to 19 bars on the MPC networks (medium pressure network type C, i.e. a pressure between 4 and 25 bars) and less than 4 bars on the MPB networks (medium pressure network type B, i.e. a pressure between 50 millibars and 4 bars),
• the maximum production capacity of the biomethane producers 17 capable of injecting biomethane into the distribution network 15, a capacity which varies from a few tens of Nm ³ /h for the smallest units, to several hundred Nm ³ /h for the biggest ones,
• 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 almost permanent operation. This exercise must also take into account the fact that the facilities of the producers 17 are not put into service simultaneously but gradually over the years.

• une unité de déshydratation 29 à l'amont de la compression 21, pour réduire les risques de condensation sur le réseau haute pression de transport, de formation d'hydrates et de corrosion,
• en option, un laboratoire d'analyse des paramètres de combustion (indice de Wobbe, pouvoir calorifique et densité de gaz) pour injecter les relevés dans le système de détermination des énergies de l'opérateur de transport.

Concerning the analysis 19 of gas compliance, there are discrepancies 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 transmission networks 10 are generally the most restrictive than those of the distribution networks 10. Thus, to guarantee that the installation of backhaul gas from the distribution network 15 to the transport network 10 fits into the operational operation of the transport network 10, the following provisions are provided:

• a dehydration unit 29 upstream of the compression 21, to reduce the risks of condensation on the high-pressure transport network, formation of hydrates and corrosion,
• as an option, a combustion parameter analysis laboratory (Wobbe index, calorific value and gas density) to feed the readings into the transport operator's energy determination system.

At the discretion of the transport operator, the analysis of other compound contents (CO ₂ , H ₂ O, THT, etc.) is optional and is only carried out if there is a proven risk of contamination of the transport network 10 (example: backflow of a biomethane with a high CO ₂ content without the possibility of dilution on the distribution 15 and transport 10 networks, or operated at a very high pressure).

Concerning gas metering 20, the reverse installation is equipped with a metering chain consisting of a meter and a local or regional energy determination device in accordance with legal metrology.

• un compresseur 21 réalisant 100 % du besoin de rebours maximum,
• deux compresseurs 21 réalisant chacun 100 % du besoin de rebours maximum où
• deux compresseurs 21 réalisant chacun 50 % du besoin de rebours maximum.

Concerning the gas compression, the compression unit makes it possible to compress the surplus of biomethane production to the service pressure of the transport network 10. Depending on economic criteria and availability of the installation, several configurations are possible, for example example

• a compressor 21 performing 100% of the maximum reverse demand,
• two compressors 21 each performing 100% of the maximum reverse demand where
• two compressors 21 each performing 50% of the maximum reverse demand.

The configuration is chosen by studying the various advantages and disadvantages in terms of cost, availability, size, and possibility of upgrading the compression unit. The suction pressure to be considered is the service pressure of the distribution network 15, which depends in particular on the injection pressures of the biomethane producers 17. The discharge construction pressure to be considered is the maximum service pressure (“PMS”) ) of the transport network, for example 67.7 bars. To ensure start-up, anti-surge protection of each compressor 21 (excluding reciprocating compressors) or stabilized recycling operation, a recycling circuit 27 fitted with a valve 28 may 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 automaton 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).

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

Concerning the regulation, the evolution of the pressure of the distribution network 15 close to the reverse installation is correlated to the gas flow passing through the reverse 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, by means of a valve 14, and of reverse . Possibilities for adapting the operating range of the suction pressure of the backhaul installation are therefore integrated, as well as 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 the delivery stations without countdown, for which the pressure is regulated on the delivery point so as to be fixed, whatever the consumption by the consumers 16. Consequently, the mode of regulation (pressure or rate) of the reverse flow to the transport network 10 is adapted to the correct operation of the reverse installation.

According to the specifications of the compressors and to avoid their deterioration or because of 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 oil-tight compressor 21, a coalescer filter 22 is installed at the outlet of compressor 21, for example with a manual drain and a visual level.

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

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

• nombre de cycles de démarrage et d'arrêt de chaque compresseur 21 et sa compatibilité avec les recommandations du fournisseur du compresseur 21,
• le démarrage et l'arrêt de chaque compresseur 21 par une routine, faisant suite à une temporisation,
• l'utilisation d'un volume tampon (non représenté) en amont de chaque compresseur 21, pour amortir les variations de pression et de débit du réseau de distribution 15.

To avoid phenomena of instability, the reverse installation must not operate simultaneously with the station 12 for expansion and delivery from the transport network 10 to the distribution network 15. Limit values for starting and stopping the countdown installation are fixed accordingly and each automaton 25 of an installation combining trigger 12 and countdown is adapted so as to prohibit the simultaneity of these two functions. The backhaul installations, during their start-up, operation and shutdown phase, limit disturbances to the upstream network (distribution 15) and the downstream network (transport 10) by avoiding in particular triggering pressure safety devices 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 the compressor 21,
• the starting and stopping of 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 variations in pressure and flow rate of the distribution network 15.

• un mode de fonctionnement automatique,
• une visualisation/supervision du fonctionnement de l'installation de rebours et
• le démarrage de l'installation de rebours.

A control and supervision function carried out by the automaton 25 makes it possible to obtain:

• an automatic operating mode,
• visualization/supervision of the operation of the reverse installation and
• the start of the reverse installation.

Data logging is performed to certify operating conditions.

In the event of an emergency, the reverse installation is isolated from the distribution network 15, by closing the valve 14. An “emergency stop” function makes it possible to stop and make the reverse installation safe. The reverse installation is also equipped with pressure and temperature safety devices 26. There is no automatic venting unless contraindicated by safety studies. The reverse installation is equipped with fire and gas detection systems 26. A means of protection against overflows is provided to protect the devices, in the form of a physical member such as a restriction orifice or by the intermediary of 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.

• le module 37 regroupe les fonctions de compression 21, de filtration 22, de refroidissement 23 et recyclage 27 et 28,
• le module 31 regroupe les fonctions de sécurité 26, de pilotage 24 et de stabilité du réseau 18,
• le module 32 regroupe les fonctions de vérification de conformité de la qualité du gaz 19 et de comptage 20 et
• le module 33 comporte la fonction de déshydratation 29.

There figure 2 represents a particular embodiment of an upgradable reverse installation 30 which is the subject of the invention. It includes the functions illustrated in figure 1 , grouped into modules:

• module 37 combines the functions of compression 21, filtration 22, cooling 23 and recycling 27 and 28,
• module 31 groups together safety 26, control 24 and network stability 18 functions,
• the module 32 combines the gas quality conformity verification functions 19 and counting 20 and
• module 33 includes dehydration function 29.

• un module 34 comporte les fonctions d'utilité, notamment d'alimentation électrique et
• un module 35 comporte un réservoir tampon pour stocker du gaz issu du réseau de distribution en amont de la compression et limiter ainsi les effets transitoires lors du déclenchement de la compression.

Two modules are added to this set of modules:

• a module 34 comprises the utility functions, in particular power supply and
• a module 35 includes a buffer tank for storing gas from the distribution network upstream of the compression and thus limiting the transient effects when the compression is triggered.

The relations of module 34 with the other modules are not represented in picture 2 , for clarity. Note, however, that the module 34 supplies electrical energy to all the other modules that consume it.

• le module de compression 37 pour la fonction de compression du gaz en cas de panne du compresseur fixe. Le compresseur est soit entrainé par le moteur du camion qui le transporte ou le tracte, soit entrainé par un moteur électrique alimenté par le module d'alimentation électrique ou le réseau électrique du site existant. Pour pouvoir s'adapter à une large gamme de débit, il est possible de raccorder plusieurs modules de compression en parallèle via un module d'interconnexion,
• le module 31 d'automatisme contenant un automate programmable afin d'acquérir l'ensemble des données nécessaires à la surveillance des différents modules fonctionnels, avec une interface homme machine permettant de visualiser l'état des modules et de passer les commandes lorsque le rebours fonctionne en mode manuel,
• le module 32 d'instrumentation contenant différents analyseurs de gaz en O₂, H₂O, CO₂ et THT ainsi qu'une unité de comptage de type transactionnel. Ce module contient également un filtre permettant de séparer les particules solides et liquides potentiellement entrainées par le gaz naturel du réseau de distribution,
• le module 33 de déshydratation (utilisation optionnelle) pour gérer les teneurs en eau différentes entre les réseaux de distribution et de transport,
• le module 34 d'alimentation électrique contenant un groupe électrogène, pour alimenter le module de compression, et un système d'alimentation sans interruption (batteries avec leur chargeur et éventuellement onduleur) pour alimenter le contrôle-commande des différents modules et
• le module 35 de ballon tampon grand volume (utilisation optionnelle) pour
  • o garantir un volume suffisamment important à l'aspiration de la compression, afin de respecter les temps de démarrage et d'arrêt du groupe de compression et
  • o avoir un volume suffisant pour absorber les surpressions en cas d'incident

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

• the compression module 37 for the function of gas compression 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 electrical power supply module or the electrical network of the existing site. To be able to adapt to a wide range of speeds, 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 allowing the status of the modules to be viewed and orders to be placed when the countdown is operating in manual mode,
• the instrumentation module 32 containing various gas analyzers for O ₂ , H ₂ O, CO ₂ and THT as well as a transaction type metering unit. This module also contains a filter to separate 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 power supply module 34 containing a generator, to power the compression module, and an uninterruptible power supply system (batteries with their charger and possibly inverter) to power the control-command of the various modules and
• the large volume buffer tank module 35 (optional use) for
  • o guarantee a sufficiently large volume at the suction of the compression, in order to respect the starting and stopping times of the compression unit and
  • o have sufficient volume to absorb overpressure in the event of an incident

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

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

Thus the commissioning of an entirely mobile reverse installation as well as the evolution of the capacities of a fixed or mobile reverse installation are easy. Indeed, it suffices to connect the various modules or to add a module to an existing installation.

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

We observe, in figure 4 , the various modules illustrated in figure 2 , in the form of standard containers allowing their transport on trucks or trailers.

We observe, in figure 5 , a reverse installation 40, which comprises a fixed part in a building, in particular a support slab 41 for the various systems, a cabinet 42 comprising the automaton 33, at least one compressor 43, and a line 44 for electrical and computer connection various systems equipped with sensors and actuators (notably valves).

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

The reception space 49 is provided with at least one gas inlet connector 83 at the first pressure, at least one gas outlet connector 81 at the second pressure and at least one energy supply 82 (gas from the distribution network 15 or electricity) for 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 pressure, 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 of each mobile compressor additional 37. Thus, the reverse installation 40 can accommodate each additional compressor without the latter having to be associated with a power supply and/or with additional pipes.

We observe, in figure 5 , the reverse installation 40 after connection of an additional mobile 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 requirements of the reverse installation 40 (failure or transient overcapacity of the biogas producers, transient drop in consumption by the gas consumers), it is added quickly and easily the mobile additional compressor 37 to the reverse installation 40. And it is removed once this temporary increase is complete.

Because the compressor module 37 is mounted on a vehicle 47 and, preferably integrated into 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 explained opposite the figure 7 . For this purpose, a mechanical connection, for example with cardan joints, connects a shaft of the engine of the vehicle 47, for example its single engine, to a shaft of the compressor. Preferably, the motor driving the additional compressor 37 is an electric motor or a gas engine using gas from the lower pressure pipe 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 reverse installation 40, compared to the supply of the stationary compressors 43 alone.

• au moins le compresseur fixe 43 entre le réseau de distribution de gaz 15 à une première pression, et le réseau de transport de gaz 10 à la deuxième pression et
• l'espace d'accueil 49 d'au moins un compresseur supplémentaire, espace muni d'au moins un connecteur 83 d'entrée de gaz à la première pression, d'au moins un connecteur 81 de sortie de gaz à la deuxième pression et, optionnellement, d'au moins un connecteur d'alimentation énergétique 82 (gaz provenant du réseau de distribution 15 ou électricité) du compresseur mobile supplémentaire 37,
• l'unité 31 de distribution pour distribuer du gaz provenant du réseau de gaz à la première pression à chaque compresseur fixe et au connecteur d'entrée de gaz à la première pression pour au moins un compresseur mobile supplémentaire 37 et
• l'unité 32 de collecte pour collecter le gaz provenant de chaque compresseur fixe et du connecteur de sortie de gaz à la deuxième pression pour chaque compresseur mobile supplémentaire 37.

In the embodiment illustrated in figure 5 , the reverse 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 equipped with at least one gas inlet connector 83 at the first pressure, at least one gas outlet connector 81 at the second pressure and , optionally, at least one power 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 to collect the gas from each stationary 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 operational fixed and additional compressors, to determine the compression capacity of the operational compressors and to control the operation of each fixed compressor and of each additional compressor according to the compression capacity of the operational fixed and additional compressors.

In figure 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 by driving from outside the installation to the reception area 49.

The modular nature of the mobile reverse installation that is the subject of the invention allows the transport network manager to only have to transport the faulty functionalities in the fixed reverse installation. Interventions are therefore simpler and system maintenance can be carried out on one part of the equipment, leaving the other parts functional.

We observe, in figure 6 , of the steps of a method for operating a mobile reverse installation that is the subject of the invention.

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

A mobile reverse installation comprises at least the automation module 31, the interconnection module 36 and a compressor module 37. The electrical power supply module 34 is preferred, but it can be replaced by a generator associated with a vehicle, as explained next to the figure 7 .

During a step 52, the modules are connected to each other via the interconnection module 36, and to the pipes of the transport 10 and distribution 15 networks. electrical energy and computer modules comprising sensors and / or actuators, for example valves.

During a step 53, the automaton 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 automaton and the motor of the compressor, or manual, the installation of the compressor being declared by an operator on a user interface of the automaton.

• des valeurs limites de pression et d'autres grandeurs physiques mesurées par des capteurs intégrés aux différents appareils présents dans l'installation et
• éventuellement, des valeurs de paramètres d'actionnement de vannes et d'autres appareils, telles que des durées de temporisation ou des courbes d'évolution.

During a step 54, the automaton defines the parameterization of the operation of the mobile reverse installation according to the operational compression capacity (that is to say including the compressor module but without taking into account the compressors broken down or stopped, for example for maintenance or updating). Parameterizing the operation 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, valve actuation parameter values and other devices, such as time delays or evolution curves.

During a step 55, the automaton controls the operation of the reverse installation.

During a step 56, the automaton receives physical quantities picked up 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 automaton controls the recycling circuit according to the operational compression capacity. Indeed, the single or joint start-up of compressors causes a pressure peak and can cause problems of maximum operating pressure (“PMS”) and minimum pressure (2.5 bars). These risks are avoided by defining limit values and the recycling circuit (re-expanding) is implemented to produce a start-up ramp and break the transient.

During a step 58, the automaton receives physical quantities picked up 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 figures 9 and 10 ). Then we return to step 56 for the next phase of putting at least one compressor into operation.

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

Preferably, provision is made for a noise barrier (20 dB) 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 the international application PCT WO2013182824 .

The mechanical actuation of the compression module 37 can also be carried out by the engine of this vehicle.

As can be seen on the figure 7 , removable connection means are arranged on the compression module 37. These removable connection means are configured to temporarily connect the connecting shaft of a compressor to a power take-off 61 of a vehicle 60. The rotation of the power take-off causes the rotation of the connecting pin and therefore that of the shaft of the compressor 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 vehicle power take-off 60.

As illustrated on the figure 7 , the removable connection means consist of a transmission shaft fitted with universal joints and a torque limiter. A first universal joint is assembled to the connecting axis and a second universal joint is assembled to the power take-off of the vehicle. These arrangements have the advantage of being able to easily transmit the rotation of the power take-off of the vehicle to the connecting axis even in the event of misalignment between these elements.

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

Thus, the automaton module 31 is connected by means of a servo cable to an adjustment device which acts on the engine of the vehicle, so as to regulate the speed of rotation of the engine and thus, to regulate the speed and, therefore, the rotational frequency of the power take-off, which makes it possible to regulate the compression carried out by the compression module 37.

The automaton module 31 is therefore programmed to transmit a setpoint to the adjustment device making it possible to achieve the servo-control of the motor. 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 potentiometer connected to the servomotor.

This servomotor makes it possible to modify the setting of the potentiometer 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 engine of the vehicle according to 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 vehicles.

In a variant 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 strut fixed in the cabin or a sufficiently heavy support, allowing assembly temporary actuation system on the floor of the vehicle. A control cylinder is mounted in a pivot connection at its rear end, on the support pillar. The piston of the control cylinder has its end mounted in a pivot connection on a control lever, one of the ends of which is mounted in a pivot connection at the lower end of the support pillar. The second end of the control lever is in contact with a pedal of the vehicle making it possible to modify the speed of rotation of the engine and, therefore, the speed of rotation of the power take-off. The automation module therefore makes it possible, by means of the servo cable, to control the control cylinder in order to regulate the speed of the motor.

In a design variant of the removable connection means between the vehicle and the compressor module 37, these may consist of an agricultural cardan transmission mechanism configured to be connected directly or indirectly via a torque to a driving axle of a vehicle of the truck, car or tractor type, for example. It may for example be two rollers capable of receiving a wheel of the vehicle. The rotation of the wheel drives that of the rollers which mesh and drive 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 tightening 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 shaft of the compressor by a cardan-type transmission.

We observe, in figure 8 , a mobile backhaul installation 30, between a gas transport network 10 and a gas distribution network 15. The gas coming from the network 15 first flows through the buffer tank module 35 then through the module 32 of verification of gas and metering compliance, the dehydration module 33, a quick-attach hose 71 and a first part 36A of the interconnection module 36. This first part 36A comprises inlet valves 72, a connection manifold for gas suction 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 flanged hose 76 to a second part 36B of the interconnection module 36. This second part 36B comprises inlet valves 77, a gas discharge connection manifold 78 and outlet valves 79. A quick-attach hose 80 connects the one of the outlet valves 79 to the transport network 10.

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

Two types of regulation envisaged for the compressor are described below. Flow regulation means that the flow passing 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 starting and stopping of the compressor when this pressure reaches limit values fixed during step 54. The figure 9 represents an example of evolution of the pressure 90 upstream of the compressor and of the flow 91 of the compressor, in a case where the compressor starting pressure limit value is at 4.2 bars and where the stopping pressure limit value of the compressor is at 2.5 bar. When the pressure decreases between these two limit values during the operation of the compressor, the automaton regulates the operation of the compressor to have a constant flow rate of 700 Nm ³ /h.

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

We see, in figure 10 , that as soon as the consumption rate on the distribution network is lower than the biomethane injection rate, the delivery station stops injecting gas from the transport network and the automaton 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 operates 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 reverse installation.

In some embodiments, the compressor is driven by a gas engine from which is taken all the hydraulic power necessary to supply the auxiliaries. 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 trailer, as in figure 11 , preferably air coolers are placed at the rear and not above the vehicle. Installation operations are thus reduced since there is no crane operation for the air coolers. The reverse installation can be left as it is on site for long-term use or the reverse installation can remain mounted on the truck or trailer during operation.

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

A mobile analysis laboratory, comprising a common chromatograph for measuring THT and gas components and a hygrometer, for example ceramic, is integrated into the reverse installation. The reverse installation can also integrate a dehydration skid and a volumetric meter for invoicing.

Several reverse installations can be installed in parallel, in particular for cases of low gas consumption and significant injection of biogas into the distribution network.

• F1 : Permettre la transmission d'un débit volumique fini de gaz depuis le réseau de distribution moyenne pression vers le réseau de transport à haute pression en période creuse,
• F2 : Garantir l'autonomie complète de l'installation de rebours mobile,
• F3 : Garantir une absence de variation en pression du réseau de distribution,
• F4 : Respecter les spécifications de conformité des réseaux,
• F5 : Respecter les spécifications de qualité des réseaux.

Functional specifications of the mobile reverse installation:

• F1: Allow the transmission of a finite gas volume flow from the medium-pressure distribution network to the high-pressure transport network during off-peak periods,
• F2: Guarantee the complete autonomy of the mobile reverse installation,
• F3: Guarantee an absence of variation in pressure of the distribution network,
• F4: Comply with network compliance specifications,
• F5: Comply with network quality specifications.

Note that the permissible 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 the pressure. The allowable CO ₂ and O ₂ contents are also different. The specifications are summarized in the table below: Transport network Distribution network _O2 <0.7% <0.75% _H2O < 53.2 mg.Nm ^-3 < 800 mg.Nm ^-3 _CO2 < 2.5% < 3.5%

In addition, the outlet temperature of the mobile reverse installation must not be lower than the recommendations applicable to the transmission network. Transactional metering covers normal compressed throughput, expressed in energy ( kWh ), 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), the regulation can be done in 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 variations, pressure regulation is chosen. 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 optimum operating range, a recycling device is implemented which makes it possible to guarantee a high pressure (at the outlet of the compressor) higher than the pressure of the transportation network. The normal flow to the compressor is constant. The pressure of the distribution network is regulated by a backpressure device. In the case where 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 drives the compressor motor.

The compressor can be a horizontal reciprocating compressor, which is 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 ratios and great flexibility in their use. A reciprocating compressor can start and run at near zero flow. Horizontal reciprocating compressors have, for example, pistons mounted in tandem. The compression chamber has a smaller area which allows the compression ratio to be increased. A double-acting piston compresses the gas on the way out and on the way back. The compression chambers are of equal areas. This configuration is more complex because 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.

Small 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 glycol water circuit passes through the cylinder liners to also cool the gas during compression.

It is preferable to valve in series downstream of the compressor in order to facilitate its start-up. Indeed, in the absence of throttling, the motor would have to overcome the back pressure of the network at a reduced speed and under these conditions the motor torque would skyrocket. Whatever the solution chosen for the regulation of the network, a relief valve or a valve downstream of the compressor is recommended for starting the machine.

Concerning the motorization, a gas motorization makes it possible to guarantee the presence of a source of energy whatever the place considered. The motors are of the industrial type.

• Teneur en THT inférieur au seuil obligatoire en aval du déshydrateur,
• Teneur en eau anormalement élevée en amont du déshydrateur,
• Teneur en eau supérieure au seuil préconisé sur le réseau de transport en aval du déshydrateur,
• Sur-qualité du gaz en amont.

Several alarms are implemented on the reverse installation:

• THT content below the mandatory threshold downstream of the dehydrator,
• Abnormally high water content upstream of the dehydrator,
• Water content above the recommended threshold on the transport network downstream of the dehydrator,
• Over-quality of gas upstream.

Transactional metering is done in energy. This energy is the product of the PCS (expressed in kWh/Nm ³ ) by the standardized volume flow.

Où l'indice 0 représente les conditions à l'état de référence et l'indice 1 les conditions à l'aspiration.Volume flow measurement instruments do not return the standardized measurement. To make the link, we will use the relation: $$D_{v,0}=D_v\cdot \frac{Z_0}{Z_1}\cdot \frac{P_1}{P_0}\cdot \frac{T_0}{T_1}$$

Where the index 0 represents the conditions at the reference state and the index 1 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 conductivity measurement and a calibration curve cannot operate over a wide range of composition covering natural gas and biomethane.

However, at the place where the mobile reverse 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 reverse installation comprises a means of obtaining the composition of the gas. The analysis of the gas composition is done by a chromatograph.

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

• Au niveau du poste de détente ou du poste rebours s'il se trouve à proximité et qu'il est équipé où
• En laboratoire, a posteriori.

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

• At the level of the expansion station or the reverse station if it is nearby and it 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 sampled at regular time intervals by an automated system (pneumatic valves).

Concerning the measurement of THT, a single analyzer equips the mobile reverse installation, downstream of the dehydrator.

The gas composition and THT (TetraHydroThiophene) 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 reverse installation incorporates an air-conditioned laboratory protected from shocks and vibrations, a laboratory which comprises 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, the influence of the back pressure is taken into account when calculating the coefficient of debt. The pressure relief valve setting is PMS (67.7) + 6% maximum. The suction valve setting is PS + 6%.

The reverse installation includes a fire control panel, with detector and extinguisher, as well as gas detection. The electrical cabinet is isolated from the compressor by a wall comprising watertight bulkhead passes.

The architecture of a mobile reverse installation mounted on a vehicle 100 is shown in figure 11 . Vehicle 100 is a fitted, containerized, pre-assembled truck or trailer comprising all the functionalities (motor-compressor and its auxiliaries, cooling circuit with fan, transaction metering, instrumentation and industrial computer).

The gas engine is supplied by the gas network of lower pressure, in order to avoid expanding the gas that one seeks to compress using the reverse. The rear part 101 comprises the air coolers. The next part, 102, has the gas engine and an air filter. The compressor is in part 103, with its auxiliaries. The front part 104 comprises the other functions of the mobile reverse installation, in particular gas analysis, metering, dehydration, remote communication, fire control panel and automatic control).

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

Small consumers (in particular 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 truck engine so that the control devices are operational immediately after transport.

The engine's cooling system, fan and lubrication are supplied by a hydraulic system, the power of which is extracted directly from the engine.

The pressure regulation is done via the servomotors of the regulators. The service valves are manual because it is not necessary to isolate the compressor from the network when the machine is shut down. 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 makes it possible to automatically adapt the number of compression stages to the input conditions. When upstream pressure is high, all compressor stages are energized simultaneously to increase flow. Conversely, when the upstream pressure is lower and the required compression ratio is higher, the compression is staged with possible intermediate cooling. This system improves the adaptation of the compressor to the operating conditions. It makes it possible to avoid 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) by being in the first mode of operation. Once the pressure has been lowered to a certain predetermined value, the compressor switches to the second mode of operation, to ensure the required compression rate.

Claims (14)

1. Backfeeding installation (30, 40), comprising:

   - modules (31 à 35 et 37) comprising 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 checking the quality compliance of the gas circulating in the compressor,

   ∘ at least one meter for metering a flow rate of gas circulating in the compressor, and

   ∘ at least one filter for filtering the gas circulating in the compressor; and

   - an interconnection 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 higher than the first pressure;

   characterized in that at least one of these modules (31 à 35, 37) is mobile, configured to be transported, in its entirety and operational by means of a removable connection to the interconnection module and to a power source, on a single vehicle.
2. Backfeeding installation (30, 40), according to claim 1, which comprises a mobile stand-alone electric power source.
3. Backfeeding installation (30, 40)according to claim 2, wherein the mobile electric power source is a generator put into operation by a vehicle motor.
4. Backfeeding installation (30, 40) according to claims 2 or 3, wherein the electric power source is a motor fueled with gas at the first pressure.
5. Backfeeding installation (30, 40)according to claims 1 to 4, wherein at least one module comprises a gas detector and/or a fire detector.
6. Backfeeding installation (30, 40) according to claims 1 to 5, wherein at least one compressor is actuated mechanically by a vehicle motor (47).
7. Backfeeding installation (30, 40) according to claims 1 to 6, wherein 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, à 35, 37) by means of an interface; and

   - a mobile collection unit (36B) for collecting the gas from each said module at a second interface.
8. Backfeeding installation (30, 40)according to claims 1 to 7, wherein the automaton is configured to control the operation of a plurality of compressors as a function of the compression capacity of the operational compressors.
9. Backfeeding installation (30, 40) according to claims 1 to 8, which also comprises at least one recycling circuit (27, 28) equipped with a valve (28), configured to expand the gas exiting from a compressor and inject it upstream from 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 the operational compressors that are put into operation jointly.
10. Backfeeding installation (30, 40) according to claim 1 to 9, which comprises a means for valve-control in series downstream from at least one compressor.
11. Backfeeding installation (30, 40) according to claims 1 to 10, which comprises a discharge device in series, downstream from at least one compressor.
12. Backfeeding installation (30, 40) according to claim 1 to 11, which comprises a system for storing gas in bottles, and a means for sampling the gas at different times, for example using pneumatic valves.
13. Backfeeding installation (30, 40) according to claims 1 to 12, which comprises a fire control unit, with detector and extinguisher, and a means for detecting gas.
14. Backfeeding installation (30, 40) according to claims 1 to 13, which comprises an electrical cabinet isolated from each compressor by a wall comprising sealed bulkhead fittings.

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