FR3062657A1 - BIO-METHANE PRODUCTION PLANT AND METHOD FOR CONTROLLING SUCH A PLANT - Google Patents

Abstract

The plant (1) comprises: - a methanizer (2), producing a flow of bio-gas; - a scrubber (7) separating the flow of biogas into a flow of bio-methane and a flow of impurities; an injection station (11) for bio-methane in a gas transmission or distribution network (13); a conditioning unit (19), configured to selectively take at least a portion of the bio-methane stream and condition the bio-methane as at least one high-density product; a storage unit (21) for the or each high-density product; a deconditioning unit (23), configured to selectively convert the or each high density product stored in the storage unit (21) to an additional flow of bio-methane and to provide the additional flow of bio-methane to the station injection (11).

Description

® FRENCH REPUBLIC

NATIONAL INSTITUTE OF INDUSTRIAL PROPERTY © Publication number: 3,062,657 (to be used only for reproduction orders) (© National registration number: 17 50920

COURBEVOIE © Int Cl ⁸ : C 12 M 1/107 (2017.01), B 01 J 19/00

A1 PATENT APPLICATION

©) Date of filing: 03.02.17. (30) Priority: (® Applicant (s): ENGIE Société anonyme - FR. (© Date of public availability of the request: 10.08.18 Bulletin 18/32. @ Inventor (s): BENOIT LAURENT and GARREC PHILIPPE. (® List of documents cited in the preliminary search report: Refer to the end of this brochure (® References to other related national documents: (® Holder (s): ENGIE Société anonyme. ®) Extension request (s): (© Agent (s): LAVOIX.

154) BIO-METHANE PRODUCTION INSTALLATION AND METHOD FOR PILOTING SUCH AN INSTALLATION.

FR 3 062 657 - A1

The installation (1) includes:

- a methanizer (2), producing a flow of bio-gas;

- a purifier (7) separating the bio-gas flow into a bio-methane flow and a flow of impurities;

- an injection station (11) for bio-methane in a gas transport or distribution network (13);

- a conditioning unit (19), configured to selectively withdraw at least part of the bio-methane flow and condition the bio-methane in the form of at least one high density product;

- a storage unit (21) of the or each high density product;

- a deconditioning unit (23), configured to selectively convert the or each high density product stored in the storage unit (21) into an additional flow of bio-methane and to supply the additional flow of bio-methane to the station injection (11).

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Installation of bio-methane production and process for controlling such an installation

The invention generally relates to installations for the production of methane from organic materials.

Such installations typically comprise a methanizer producing a flow of bio-gas containing methane and impurities, and a purifier separating the impurities from the flow of bio-methane. The bio-methane flow feeds an injection station, which injects it into a gas transport or distribution network.

Such installations frequently operate at an average capacity at least 25% below their maximum production capacity.

Several factors explain why the rate of use of the facilities is so low.

On the one hand, certain technical problems induce a reduction or a stop of the production. For example, production can be stopped or slowed down to perform scheduled maintenance. Production is also occasionally stopped or unexpectedly slowed down due to unexpected technical problems.

It also happens that an anomaly in the operation of the methanizer or the purifier leads to the production of a methane flow which does not comply with the network specifications. For example, methane can contain an excessively high rate of an impurity such as H ₂ S, CO ₂ or H ₂ O. The injection station is typically equipped with a methane quality measurement system , for example a chromatograph. If this system detects a non-conformity, it prevents the injection of methane on the network, and for example drifts it towards a torch where the methane is burned.

It also happens that the methane producer voluntarily reduces its production, so as not to exceed certain thresholds. Indeed, according to the regulations in force in the country where the installation is located, the subsidized feed-in tariff for methane depends on the quantity produced.

Too frequent overshooting, more than twice a year in France for example, of the monthly quantity of methane specified in the application for regulatory approval of the installation leads to the loss of the subsidized tariff for the overproduction carried out. This overproduction is then sold at the gas market price, significantly lower than the subsidized rate. This price does not cover all production costs, and the producer may sell methane exceeding the monthly limit at a loss.

If the overshoot is too large, it can also lead to a drop in the feed-in tariff for the entire production, and not only for the quantity exceeding the authorized limit. This results in an overall decrease in the income of the bio-methane producer.

Thus, the producer of bio-methane generally tries to control the quantity of methane produced to keep it below the authorized limit. However, since the production of gas from organic materials calls for physical or chemical processes which have a great inertia (thirty to fifty days between the supply of the methanizer and the actual production of gas), it is very difficult to control finely the flow of gas produced so as to approach as close as possible to the authorized limit. This leads bio-methane producers to voluntarily restrict their production to a level well below the authorized limit, to avoid any runaway of methane production which could lead to exceeding the production limit, even on an ad hoc basis.

In addition, the capacity of the gas transmission or distribution network to receive methane production varies seasonally. This variation is due to changes in the quantities of gas consumed by consumers connected to the network.

Indeed, a large number of bio-methane production facilities are located in rural areas, that is to say in areas where the use of network gas is linked to heating needs. In summer, gas consumption in these rural areas drops so much that it may be less than local production of bio-methane. There is simply no more room on the network for the quantities of bio-methane produced by the installations. This phenomenon is further accentuated at night and on public holidays during the summer.

The producer must then anticipate well in advance, typically at least a month, this drop in consumption, by reducing the feed to his methanizer and therefore by restricting his production. Alternatively, it can burn the excess bio-methane produced in a dedicated flare.

Thus, the reasons mentioned above contribute to underuse the bio-methane production facility, and to economically recover only part of the production capacity of this facility.

One solution to improve the situation would be to be able to store part of the gas produced by the methanizer.

It would be particularly interesting to be able to store one to two whole production days, so as to collect the quantity of gas produced during maintenance operations or in periods of low consumption such as weekends and holidays.

It would be even more advantageous to be able to store several weeks of production, to collect the gas produced when the gas transport or distribution network is saturated over long periods, for example for several weeks in summer.

A first possibility consists in storing the gas directly in the methanizer. The quantity of gas thus stored is limited by the maximum acceptable gas pressure inside the methanizer. In any event, the maximum quantity of gas that can be stored in a methanizer is between four and eight hours of production. This is clearly insufficient with regard to the needs set out above.

Another possibility consists in using gasometers, making it possible to store substantially at atmospheric pressure the gas produced by the methanizer. Gasometers store a maximum of 5000 Nm ³ of gas, or approximately 2500 Nm ³ of methane. A methanizer typically produces 250 Nm ³ / h of bio-gas. Gasometers therefore allow just over a day of production to be stored.

Increasing the storage capacity per gasometer is possible, but leads to considerable investment costs.

Alternatively, it is also possible to burn the surplus bio-gas in a dedicated torch, but this solution has the defect that the production of bio-gas is lost.

Thus, there is no technical solution to operate a methanizer at its maximum production capacity for a long time.

In this context, the invention aims to propose an installation not having the above defect.

To do this, the invention relates to a bio-methane production installation, the installation comprising:

- a methanizer, producing a flow of bio-gas from organic matter, the bio-gas comprising methane and impurities;

- a purifier separating the bio-gas flow into a bio-methane flow essentially comprising methane and a flow of impurities;

- an injection station, configured to inject the bio-methane flow into a gas transport or distribution network;

- a conditioning unit, configured to selectively take at least part of the bio-methane flow and condition the bio-methane in the form of at least one high density product;

- a storage unit for or each high density product;

- a deconditioning unit, configured to selectively convert the or each high density product stored in the storage unit into an additional flow of bio-methane and to supply the additional flow of bio-methane to the injection station.

The packaging unit and the storage unit, in the event of biogas overproduction by the methanizer with regard to the flow which can be absorbed by the gas transport or distribution network, make it possible to store part of the production. Methane is stored as a high density product, so that a significant amount of gas can be stored.

It becomes possible to store several weeks of production without the storage occupying an excessive volume. The cost of storage therefore becomes reasonable.

On the contrary, during periods when the production installation does not supply enough methane to meet the needs of the transmission or distribution network, the deconditioning unit makes it possible to supply an additional quantity of methane, which is added to that produced by the methanizer.

It therefore becomes possible to operate the methanizer at a level close to its maximum capacity, over a long period, practically throughout the year.

The installation may also have one or more of the characteristics below, considered individually or in any technically possible combination:

- the or each high density product contains at least 50 Nm3 of bio-methane per m3 of high density product;

- the or each high density product is chosen from the following list: methane at a pressure greater than 50 bars; LNG; methane hydrate, solid or in suspension form; methane adsorbed on a solid adsorbent material;

- the high density product is LNG, the packaging unit comprising a liquefaction device, the storage unit comprising at least one cryogenic tank and a recycling circuit configured to return a gaseous phase from a sky of the cryogenic tank to the liquefaction system;

- the methanizer has a maximum bio-methane production capacity, the storage unit having a storage capacity greater than two weeks of production of the methanizer at its maximum bio-methane production capacity;

- the packaging unit has a start-up time of less than 12 hours;

- the deconditioning unit has a start-up time of less than 12 hours;

- the methanizer has a maximum bio-methane production capacity, the deconditioning unit having a bio-methane production capacity greater than 50% of the maximum bio-methane production capacity of the methanizer;

- the installation is configured to allow the biomethane to be supplied to the injection station simultaneously by the purifier and by the deconditioning unit;

- the installation includes a destocking unit, configured to export the high density product out of the installation or to supply a combustion unit;

- the installation is configured to simultaneously allow:

- injection into the gas transport or distribution network by the injection station of part of the flow of bio-methane supplied by the purifier;

- the conditioning by the conditioning unit of another part of the bio-methane flow supplied by the purifier; and

- possibly the export of the high density product outside the installation by the destocking unit or the supply of the combustion unit;

- the installation includes a controller configured to acquire a parameter representative of the need for the methane gas transport or distribution network, to acquire a flow rate of bio-methane produced by the methanizer, and for:

- activate the conditioning unit if the bio-methane flow is greater than the need of the transport or distribution network;

- activate the deconditioning unit if the bio-methane flow is lower than the need of the transmission or distribution network.

- the high density product is methane at a pressure above 50 bars, and the storage unit comprises at least one high pressure gas tank;

- the high density product is methane at a pressure greater than 50 bars, and the deconditioning unit includes a pressure reducer, or a JouleThomson type valve, or an expansion turbine;

- the high density product is LNG, and the storage unit includes at least one cryogenic tank;

- the high density product is LNG, and the deconditioning unit includes a vaporizer;

- the high density product is methane hydrate, solid or in suspension form, and the storage unit comprises at least one thermally insulated tank;

the high density product is methane hydrate, solid or in the form of a suspension, and the deconditioning unit comprises a device for heating and dehydrating the methane hydrate;

- The high density product is methane adsorbed on a solid adsorbent material, and the storage unit comprises at least one sealed tank, containing the solid adsorbent material;

- the high density product is methane adsorbed on a solid adsorbent material, and the deconditioning unit comprises a suction device, configured to keep the tank sealed at a pressure below a determined limit.

According to a second aspect, the invention relates to a method for controlling a methane production installation having the above characteristics, the method comprising the following steps:

- acquisition of a parameter representative of the need for the methane gas transport or distribution network;

- acquisition of a flow of bio-methane produced by the methanizer;

- activation of the packaging unit if the bio-methane flow is greater than the need of the transport or distribution network;

- activation of the deconditioning unit if the bio-methane flow is lower than the need of the transmission or distribution network.

The piloting process can also have the characteristics below:

- the methanizer operates continuously at a capacity greater than 90% of its maximum methane production capacity.

Other characteristics and advantages of the invention will emerge from the detailed description which is given below, for information and in no way limitative, with reference to the figures below among which:

- Figure 1 is a simplified schematic representation of the methane production installation of the invention;

- Figure 2 is a simplified schematic representation of a methanizer; and

- Figure 3 is a simplified schematic representation of the packaging, storage and deconditioning units in the case where the high density product is LNG.

The installation 1 shown in Figure 1 is intended to produce bio-methane (CH ₄ ). The installation 1 comprises a methanizer 2, producing a flow of bio-gas from organic materials.

Here we refer to bio-methane and bio-gas respectively the flows of methane and gas produced from organic matter by the methanizer.

The methanizer 2 is of any suitable type.

It implements a biological process of degradation of organic matter, by bacteria, in the absence of oxygen and at constant temperature.

The organic matter used includes for example animal excrement (manure, slurry), crop residues such as straw, or plants such as corn, grass, sorghum, etc.

The organic matter used can also contain residues from the food industry (grease, oil), or communities (lawn mowing, sewage treatment plant mud, etc.).

Methanation results from a series of biological reactions, carried out by several types of microorganisms.

The methanizer 2 comprises a tank 3, as illustrated in FIG. 2. The tank 3 is covered with a membrane 4 impermeable to bio-gas.

The organic matter being treated is typically found in the form of a sludge inside the tank 3. It is constantly stirred. It stays there for one to two months, and is broken down into a liquid called "digestate" and a gas called biogas.

The digestate includes water and organic matter residues that are not converted to gas.

The bio-gas resulting from the fermentation of organic matter accumulates above the tank, under the membrane 4. The bio-gas typically comprises at least 50% methane.

More specifically, the biogas flow typically comprises between 50 and 75% of methane (CH ₄ ), between 25 and 45% of carbon dioxide (CO ₂ ), between 2 and 7% of water vapor (H ₂ O), as well as small amounts of nitrogen (N ₂ ), hydrogen (H ₂ ), oxygen (O ₂ ) and hydrogen sulfide (H ₂ S).

The methanizer 3 produces for example 250 Nm ³ / h of bio-gas.

Typically, the flow of bio-gas leaves the methanizer 2 at a pressure close to atmospheric pressure, for example at a pressure of 80 mbar relative.

The installation 1 also comprises a purifier, 7 connected to the methanizer 2 by a bio-gas conduit 5. The purifier 7 separates the flow of bio-gas into a flow of biomethane essentially comprising methane, and a flow of impurities.

Such a purifier 7 is of known type, and will not be described here.

The bio-methane stream comprises at least 90% methane by volume, preferably at least 95% methane by volume, and typically about 97% methane by volume.

All other gases are present in the impurity stream.

The installation 1 also includes an injection station 11, connected to the purifier 7 by a methane pipe 9. The injection station 11 is configured to inject the stream of bio-methane into a transport or distribution network gas 13. The injection station 11 is of known type and will not be described in more detail here.

When the network 13 is a gas distribution network, it is typically at a pressure between 3 and 12 bar absolute.

The flow of bio-methane leaving the purifier 7 is at the pressure, or at a pressure close to that of the gas circulating in the distribution network 13.

When the network 13 is a gas transport network, it is typically at a pressure between 20 and 67 bar, or at a pressure between 20 and 85 bar.

In this case, the installation 1 advantageously comprises a compression unit 14, configured to compress the bio-methane circulating in the methane pipe 9 to the pressure, or to a pressure close to that of the gas circulating in the transport network

13.

Advantageously, the injection station 11 includes a methane quality measurement system, configured to measure the level of impurities in the biomethane flow, in particular the proportion of CO ₂ , H ₂ O and H ₂ S .

The installation 1 preferably includes a flare 15, the station 11 being configured to direct the flow of bio-methane to the flare 15 if the quality of the methane is not adequate to be able to inject it into the transport or distribution

13.

The installation 1 may advantageously include another flare 17, visible in FIG. 1. The methanizer 2 is configured to direct all or part of the flow of bio-gas to the flare 17, in particular for safety reasons if the pressure of bio -gas inside the methanizer 2 is too strong.

The gas transport or distribution network 13 is designed to serve a plurality of gas consumers. The gas circulating in the network 13 comes from a gas source, other than the methanizer 2, for example from an LNG terminal.

Installation 1 also includes:

-a conditioning unit 19, configured to selectively take at least part of the bio-methane flow and condition the bio-methane in the form of a high density product;

a unit 21 for storing the high density product;

- a deconditioning unit 23, configured to selectively convert the high density product stored in the storage unit 21 into an additional flow of bio-methane and to supply the additional flow to the injection station 11.

The inlet of the packaging unit 19 is fluidly connected to the methane pipe 9 by a pipe 27. The outlet of the packaging unit 19 is fluidly connected to the storage inlet 21 by a pipe 29, the outlet storage 21 being connected to the inlet of the deconditioning unit 23 by a pipe 31. The outlet of the deconditioning unit 23 is fluidly connected to the methane pipe 9 by a pipe 33, possibly opening upstream of the compression unit 14.

The high density product contains at least 50 Nm ³ of bio-methane per m ³ of high density product. Preferably, it contains at least 100 Nm ³ of bio-methane per m ³ of high density product and more preferably at least 150 Nm ³ of bio-methane per m ³ of high density product.

One Nm ³ corresponds to one m ³ of gas at 0 ° C and 101,300 Pa.

According to a first embodiment, the high density product is methane stored at a pressure greater than 50 bars, preferably a pressure greater than 100 bars, and more preferably at a pressure between 150 and 250 bars.

In this case, the packaging unit 19 comprises at least one compressor; and preferably a device for desuperheating the bio-methane, so as to increase its density and density.

One m ³ of high pressure bio-methane contains for example 250 Nm ³ of biomethane.

In this embodiment, the storage unit 21 comprises at least one high pressure gas tank.

The compressor is for example a compressor sold under the name "CNG compress" by the company ARIEL Corporation, Mount Vernon, Ohio, USA.

Typically, the storage unit 21 includes a plurality of high pressure gas tanks. These tanks are, for example, tubes or spheres sold under the name "Cascade Storage" by the company GREEN LINE FUEL CORP, Temecula, California, USA.

In this embodiment, the deconditioning unit 23 includes a pressure reducer. This regulator is configured to expand the methane at high pressure to the pressure of the network 13.

Such regulators are known and will not be described in detail here.

According to a second embodiment, the high density product is LNG (liquefied natural gas).

LNG is typically at a temperature between -120 ° C and -160 ° C, and at a pressure between 1 and 12 bar absolute.

In this case, one m ³ of high density product contains approximately 580 Nm ³ of bio-methane.

In this embodiment, the packaging unit 19 comprises a liquefaction device. This liquefaction device is typically a small capacity liquefaction device sold by the company CRYOSTAR, Hésingue, France.

Advantageously, the liquefaction device provides additional purification of the bio-methane.

This additional purification is carried out for example by the devices and by the processes marketed by the company CHAUMECA, Haubourdin, France.

In this embodiment, the storage unit 21 comprises at least one, preferably a plurality, of cryogenic tanks 35 (Figure 3). These cryogenic tanks are of the type marketed for example by the companies EUROTAINER, Levallois-Perret, France or CRYONORM BV, LH Alphan aan den Rijn, Netherlands.

In this case, the deconditioning unit 23 typically includes a vaporizer, configured to vaporize the LNG. This vaporizer is for example of the type marketed by the company CRYONORM BV under the name "LNGAMBIENT AIR VAPORIZER".

In such vaporizers, LNG is vaporized by heat exchange with the ambient air.

According to an advantageous variant of the invention, the storage unit 21 comprises a recycling circuit 37 configured to return a gaseous phase from the sky from the cryogenic tank 35 to the liquefaction device of the conditioning unit 19 (FIG. 3) .

Indeed, although the cryogenic tank 35 is thermally insulated, there is ultimately a very partial evaporation of the LNG, the gas accumulating in the sky 39 of the cryogenic tank 35. The recycling circuit 37 allows the gaseous phase to be taken accumulating in the sky 39, and returning it upstream of the conditioning unit 19. The gas phase is thus reliquefied and returns to the cryogenic tank 35 after passing through the liquefaction device.

Thanks to this aspect of the invention, it is possible to store LNG in storage unit 21 without a time limit.

According to a third embodiment, the high density product is a methane hydrate. Such a methane hydrate is obtained by mixing the methane with pure water, at a temperature close to -15 ° C.

In this case, one m ³ of high density product contains approximately 170 Nm ³ of biomethane.

A conditioning unit 19 adapted to produce a methane hydrate is described in US 2012/0232318 and in the article "Methane hydrate pellet transport using the self-preservative effect: a techno-economic analysis", published in the journal Energies, 2012, 5, pages 2499-2523.

Methane hydrate is in the form of a solid or in the form of a suspension. When methane hydrate is stored in solid form, it is for example in the form of granules.

In this case, the storage unit 21 advantageously comprises at least one, preferably several thermally insulated tanks. Methane hydrate is stored inside the tank, at a temperature of around -15 ° C.

In this third embodiment, the deconditioning unit 23 includes a device for heating and dehydrating methane hydrate.

According to a fourth embodiment, the high density product is methane adsorbed on a solid adsorbent material.

In this case, one m ³ of high density product contains approximately 190 Nm ³ of methane.

In this embodiment, the packaging units 19 and storage units 21 are combined. The packaging and storage unit includes a sealed tank containing the solid adsorbent material. This solid adsorbent material is for example activated carbon. This unit is configured to allow the adsorption of methane, by circulation of methane coming from methane pipe 9, at high pressure and low temperature, in contact with the material. For example, bio-methane is circulated at a pressure of around 30 bar and at room temperature.

In this fourth embodiment, the deconditioning unit 23 comprises a suction device, configured to keep the tank sealed at a pressure below a determined limit. A decrease in the internal pressure in the sealed tank indeed causes the desorption of methane. As a variant or in addition, the deconditioning unit 23 includes a heater, configured to heat the adsorbent material stored in the sealed tank.

Optionally, the deconditioning unit 23 includes a compressor, configured to compress the additional flow of bio-methane to the pressure necessary for injection into the gas transmission or distribution network 13.

Technical solutions for packaging, storage and deconditioning with a solid adsorbent material are marketed for example by the companies CENERGY SOLUTIONS (Houston, Texas, USA), or ANGP (Adsorbed Natural Gas Product, Inc., Chester, New-Jersey , USA).

Advantageously, and whatever the type of high density product chosen, the storage 21 has a storage capacity greater than two weeks of production of the methanizer 2 than its maximum bio-methane production capacity.

As explained above, this makes it possible to store the production of the methanizer during periods when the consumption of consumers connected to the network 13 is durably low, as in summer.

Advantageously, the packaging unit 19 has a start-up time of less than twelve hours, preferably less than 6 hours, more preferably less than 1 hour.

Similarly, the deconditioning unit 23 also advantageously has a start-up time of less than twelve hours, preferably less than 6 hours, more preferably less than 1 hour.

This makes it possible to quickly adapt the quantity of bio-methane sent to the injection station 11, and to finely follow the variations in the methane requirement of the gas transmission or distribution network 13.

Still with this in mind, the deconditioning unit 23 has a bio-methane production capacity greater than 50% of the maximum biomethane production capacity of the methanizer 2. It is therefore possible to respond to a temporary variation in methane demand of the transmission or distribution network 13, for example a peak consumption in the network 13 at the start and at the end of the day.

According to another advantageous aspect of the invention, the installation 1 comprises a destocking unit 41, configured to export the high density product out of the installation, or to supply a combustion unit 43.

The destocking unit 41 typically takes the high density product from the storage unit 21.

The high density product is for example exported in the form of vehicle fuel. In this case, it is typically in the form of high pressure methane, or in the form of LNG.

The destocking unit 41 is for example provided for delivering the high density product to the retail, locally, that is to say in installation 1 or near installation 1. It makes it possible for example to supply fuel for local agricultural vehicles 45 or any other local industrial vehicle. This solution is to be considered if installation 1 is located in a farmer producing the organic matter feeding the methanizer.

As a variant, the destocking unit 41 is intended to supply the high density product in greater quantity, for transport thereof to service stations external to the installation 1, which will distribute the fuel for the vehicle.

The high density product is for example transported by tank trucks 47, or even by a conduit if the service station is not too far away.

When the high density product is LNG, the destocking unit 41 is alternatively configured to deliver LNG at retail, so as to supply industrial boilers. LNG is transported to industrial boilers by tankers 47 or by pipes.

As explained above, the destocking unit 41 is configured in a variant to supply a combustion unit 43. The combustion unit 43 is either an integral part of the installation 1, or a separate installation, installed at a distance from the bio-methane production facility.

When the combustion unit is part of the installation 1 for producing biomethane, the destocking unit 41 delivers the high density product to the combustion unit 43 via a conduit. When the combustion unit 43 is separate from the installation 1, the destocking unit 41 is configured to supply the high density product to a means of transport such as a tank truck 47.

Combustion unit 43 burns bio-methane and provides either heat or electricity, or both heat and electricity.

According to an advantageous aspect of the invention, the installation 1 is configured to allow the injection station 11 to be supplied with methane simultaneously by the purifier 7 and by the deconditioning unit 23. Thus, it is possible to rapidly increase methane production to keep up with the needs of the transmission or distribution network 13.

According to another aspect, the installation 1 is configured to simultaneously allow:

- the injection into the gas transmission or distribution network 13 by the injection station 11 of part of the flow of bio-methane supplied by the purifier 7;

- the conditioning by the conditioning unit 19 of another part of the stream of bio-methane supplied by the purifier 7; and eventually

- the export of the high density product by the destocking unit 41, or the supply of the combustion unit 43.

It is thus possible to remove the excess production from the methanizer at any time. It is also possible to respond to a temporary request to export the high density product, for example a peak consumption of LNG by agricultural machinery at the start of the week or during harvest periods.

The installation 1 comprises a controller 49. It also includes controlled valves 51, interposed on the lines 27, 29, 31 and 33. These valves are controlled by the controller 49. They make it possible to start or interrupt the circulation in the conduits 27, 29, 31, 33. The controller 49 can thus start or stop the conditioning unit 19 and the deconditioning unit 23. The controller 49 also controls all the active members of the conditioning unit 19, of the storage unit 21 and of the deconditioning unit 23. It also controls the possible destocking unit 41.

The controller 49 is also configured to acquire a parameter representative of the need for the gas transport or distribution network 13 in methane, and to acquire a flow rate of bio-methane produced by the methanizer 2.

The parameter representative of the need for the gas transport or distribution network 13 in methane is for example provided by the unit controlling the gas transport or distribution network 13.

The bio-methane flow rate is supplied to the controller 49 for example by a flow rate measurement probe 53, preferably located in line 9 or installed in line 5.

Advantageously, the controller 49 is programmed to:

-activate the conditioning unit 19 if the methane flow is greater than the needs of the conditioning network 13;

- activate the deconditioning unit 23 if the methane flow is less than the needs of the transmission or distribution network 13.

The invention also relates to a method for controlling a bio-methane production facility 1 as described above.

The process includes the following steps:

- acquisition of a parameter representative of the need for the gas transport or distribution network 13 in methane;

- acquisition of a methane flow produced by the methanizer 2;

- activation of the conditioning unit 19 if the methane flow is greater than the needs of the transmission or distribution network 13;

- activation of the deconditioning unit 23 if the methane flow is less than the needs of the transmission or distribution network 13.

The conditioning and deconditioning units 19, 23 are activated as described above, by the controller 49, by actuating the controlled valves 47 and possibly the active members of the conditioning, storage 21 and deconditioning 23 units.

Preferably, the methanizer 2 operates continuously at a capacity greater than 90% of its maximum bio-methane production capacity, preferably greater than 95% of its maximum production capacity.

Thus, the invention makes it possible to find an outlet for the bio-gas produced during periods when it cannot be recovered, due to the mismatch between the quantity of bio-gas produced by the methanizer 2 and the needs of the transmission or distribution network 13.

The invention makes it possible to store the bio-methane produced in the form of a high density product, for a long period of time, and allows it to be reinjected later in the transport or distribution network 13. Thus, one does not change the type of economic recovery of methane, but the injection is delayed over time until it is again possible. The injection is carried out during peak daily or weekly consumption, or even during periods of high annual consumption, in autumn or winter when gas consumption is highest.

When installation 1 is equipped with a destocking unit, it is possible to recover bio-methane in other forms, when their recovery is advantageous for the producer. It is thus possible to recover bio-methane in the form of vehicle fuel, or in the form of LNG to supply industrial boilers, or even by combustion, for the production of electricity and / or heat.

It should be noted that the installation 1 can be configured for the storage of methane in the form of several different types of high density products. In this case, the packaging, storage and deconditioning units each contain means adapted to each type of high density product.

These means have been described above.

According to another advantageous aspect of the invention, the packaging unit 19, the storage unit 21 and the deconditioning unit 23 are transportable. Each unit consists of a single module or a small number of modules. These modules can be routed by road either directly (for example in the case of an LNG tank), or by being previously arranged on a transport support, commonly called skid in English.

The assembly of the modules is simple, since it consists only in connecting the inputs and outputs of each module to each other, by means of fixing flanges, flexible tubes or welded tubes.

Installation on the ground is simplified, and either does not require any particular fixing (example of tanks for LNG), or only requires fixing dowels on conventional concrete slabs.

Claims (14)

1. - Bio-methane production installation, installation (1) comprising: - a methanizer (2), producing a flow of bio-gas from organic matter, the biogas comprising methane and impurities; - a purifier (7) separating the flow of bio-gas into a flow of bio-methane comprising essentially methane and a flow of impurities; - an injection station (11), configured to inject the stream of bio-methane into a gas transport or distribution network (13); - a packaging unit (19), configured to selectively take at least part of the bio-methane flow and package the bio-methane in the form of at least one high density product; - a storage unit (21) of the or each high density product; - a deconditioning unit (23), configured to selectively convert the or each high density product stored in the storage unit (21) into an additional flow of bio-methane and to supply the additional flow of bio-methane to the station injection (11). 2. - Installation according to claim 1, wherein the or each high density product contains at least 50 Nm ³ of bio-methane per m ³ of high density product. 3. - Installation according to claim 1 or 2, wherein the or each high density product is chosen from the following list: methane at a pressure greater than 50 bars; LNG; methane hydrate, solid or in suspension form; methane adsorbed on a solid adsorbent material. 4. - Installation according to claim 3, wherein the high density product is LNG, the packaging unit (19) comprising a liquefaction device, the storage unit (21) comprising at least one cryogenic tank (35 ) and a recycling circuit (37) configured to return a gas phase from an overhead from the cryogenic tank (35) to the liquefaction device. 5. - Installation according to any one of the preceding claims, in which the methanizer (2) has a maximum bio-methane production capacity, the storage unit (21) having a storage capacity greater than two weeks of production of the methanizer (2) to its maximum bio-methane production capacity. 6. - Installation according to any one of the preceding claims, in which the conditioning unit (19) has a start-up time of less than 12 hours. 7. - Installation according to any one of the preceding claims, in which the deconditioning unit (23) has a start-up time of less than 12 hours. 8. - Installation according to any one of the preceding claims, in which the methanizer (2) has a maximum bio-methane production capacity, the deconditioning unit (23) having a bio-methane production capacity greater than 50% of the maximum bio-methane production capacity of the methanizer (2). 9. - Installation according to any one of the preceding claims, in which the installation (1) is configured to allow the supply of bio-methane to the injection station (11) simultaneously by the purifier (7) and by the deconditioning unit (23). 10. - Installation according to any one of the preceding claims, comprising a destocking unit (41), configured to export the high density product out of the installation (1) or to supply a combustion unit (43). 11. - Installation according to claim 10, configured to simultaneously allow: - the injection into the gas transport or distribution network (13) by the injection station (11) of part of the flow of bio-methane supplied by the purifier (7); - conditioning by the conditioning unit (19) of another part of the biomethane flow supplied by the purifier (7); and - possibly the export of the high density product outside the installation (1) by the destocking unit (41) or the supply to the combustion unit (43). 12. - Installation according to any one of the preceding claims, comprising a controller (49) configured to acquire a parameter representative of the need of the gas transmission or distribution network (13) in methane, to acquire a flow rate of bio-methane produced. by the methanizer (2), and for: - activate the packaging unit (19) if the bio-methane flow is greater than the need of the transport or distribution network (13); - activate the deconditioning unit (23) if the bio-methane flow is lower than the need for the transmission or distribution network (13). 13. - Method for controlling a bio-methane production installation according to any one of the preceding claims, the method comprising the following steps: - acquisition of a parameter representative of the need for the gas transport or distribution network (13) in methane; - acquisition of a bio-methane flow produced by the methanizer (2); - activation of the conditioning unit (19) if the bio-methane flow is greater than the need of the transport or distribution network (13); - activation of the deconditioning unit (23) if the bio-methane flow is less than the 5 need of the transport or distribution network (13). 14, - The control method according to claim 13, wherein the methanizer (2) operates continuously at a capacity greater than 90% of its maximum methane production capacity. 1/2 Γ * - * » 2/2