Installation for the methanization of organic matter

Abstract

Installation for the methanization of organic matter The present invention relates to a methanization installation (10), comprising: a digestion corridor (12), capable of receiving organic matter, - a gas collector (14), surmounting the digestion corridor; and - an introduction device (16) and an evacuation device (18) for organic matter, arranged at the ends of the digestion corridor; the digestion corridor comprising a substantially cylindrical surface extending in the longitudinal direction; the installation being characterized in that the digestion corridor further comprises: an introduction zone (32), having a continuously increasing width; and an evacuation zone (34), having a continuously decreasing width. Figure for abstract: Figure 1

Description

Title of the invention: Installation for the methanization of organic matter

[0001] The present invention relates to a methanization installation, of the type comprising: a digestion corridor, capable of receiving organic matter, said corridor extending in a substantially linear manner in a horizontal longitudinal direction, between a first and a second end; a gas collector, surmounting the digestion corridor; and an introduction device and an evacuation device for organic matter, arranged respectively at the first and second ends of the digestion corridor; the digestion corridor comprising a main zone, said main zone having a substantially cylindrical surface extending in the longitudinal direction.

[0002] Methanization makes it possible, in particular, to recover organic matter from agriculture, such as slurry or manure. Through a fermentation or digestion process, said organic matter produces biogas, or digestion gas, and a solid residue, or digestate.

[0003] The present invention relates more particularly to so-called “dry” methanization. In this type of methanization, the organic matter comprises a certain quantity of dry matter, which makes it difficult or impossible to pump by a rotor pump.

[0004] In particular, when the organic matter comprises both a certain quantity of water and a certain quantity of straw, said organic matter has physical properties of a solid at its center and physical properties of a liquid at its periphery. It is thus possible to cause a linear movement of said organic matter, respectively by feeding it and discharging it at each of the ends of the path.

[0005] A methanization installation, carried out on this principle, is known from document FR3107637 in the name of the Applicant.

[0006] However, such a methanization installation does not offer an optimal result in terms of movement of organic matter between the inlet and the outlet.

[0007] The object of the invention is to improve the existing installation. To this end, the subject of the invention is a methanization installation of the aforementioned type, in which the digestion corridor further comprises: an introduction zone, having a continuously increasing width between the first end and the main zone; and an evacuation zone, having a continuously decreasing width between the main zone and the second end.

[0008] According to other advantageous aspects of the invention, the installation comprises one or more of the following characteristics, taken individually or in all technically possible combinations:

[0009] - in a transverse direction, perpendicular to the longitudinal direction, to the at least one of the introduction zone and the evacuation zone is delimited by two first substantially flat walls;

[0010] - each of the first two walls is substantially vertical;

[0011] - each of the first walls forms a first angle between 30° and 60°, pre preferably between 35° and 55°, more preferably between 40° and 50°, with the longitudinal direction;

[0012] - the digestion corridor has two second walls facing upwards, each of said second walls being inclined relative to the vertical, by a second angle between 30° and 60°, preferably between 40° and 50°;

[0013] - the digestion corridor further comprises a substantially horizontal bottom, connecting the two second walls;

[0014] - the main area of ​​the digestion corridor has two third walls sen possibly vertical, each of said third walls extending upwards one of the second walls;

[0015] - the introduction device comprises: an introduction conduit, opening onto the first end of the digestion corridor; and a pusher, capable of pushing the organic matter towards said first end;

[0016] - the introduction conduit comprises: a drop portion, extending vertically wedge; and a deflection portion, configured to introduce the organic matter into the digestion corridor according to a substantially horizontal movement; the pusher being able to move according to a vertical stroke in the drop portion;

[0017] - the deflection portion comprises a slide inclined towards the first end of the digestion corridor.

[0018] The invention further relates to a method of constructing an installation as described above, comprising the following steps: making an excavation in a ground; and applying a membrane to said excavation, so as to form the second walls.

[0019] The invention will appear more clearly on reading the description which follows, given solely by way of non-limiting example, and made with reference to the drawings in which:

[0020] [Fig-1] [Fig.l] is a longitudinal sectional view of a meth installation nization according to an embodiment of the invention;

[0021] [Fig.2] [Fig.2] is a horizontal sectional view of the installation of [Fig.l]; and

[0022] [Fig.3] [Fig.3] is a cross-sectional view of the installation of Figures 1 and 2.

[0023] Figures 1 to 3 represent a methanization installation 10, according to one embodiment of the invention.

[0024] The installation 10 comprises: a digestion corridor 12; a gas collector 14; an introduction device 16; an evacuation device 18; and an electronic control module 20, shown schematically in [Fig.l].

[0025] In the embodiment shown, as will be specified later, the installation 10 is partially buried in a ground 22, said ground being defined by a surface 24. In the present description, it is considered that the surface 24 of the ground 22 is substantially horizontal and oriented upwards.

[0026] We consider an orthonormal base (X, Y, Z) associated with the installation 10, the direction Z representing the vertical.

[0027] The digestion corridor 12 of the installation 10 is capable of receiving organic matter to be digested. Said corridor 12 extends in a substantially linear manner between a first 26 and a second 28 end. It is considered that the corridor 12 extends in the longitudinal direction X. Each end 26, 28 is materialized by a wall extending substantially in a plane (Y, Z).

[0028] Generally, the digestion corridor 12 has the shape of an upwardly open channel.

[0029] More specifically, the digestion corridor 12 comprises: a main zone 30, an introduction zone 32; and an evacuation zone 34.

[0030] The main zone 30 has a substantially cylindrical surface 36 extending in the longitudinal direction X. By “substantially cylindrical surface”, it is meant that the surface 36 is substantially formed of generating lines parallel to X. The shape of the surface 36 in the embodiment shown will be specified later.

[0031] The introduction zone 32 is arranged along X between the first end 26 of the corridor 12 and the main zone 30. The evacuation zone 34 is arranged along X between the main zone 30 and the second end 28 of the corridor 12.

[0032] A length along X of the main zone 30 is significantly greater than lengths along X of the introduction 32 and evacuation 34 zones.

[0033] As will be specified later, the introduction zone 32 has a continuously increasing width between the first end 26 and the main zone 30; and the evacuation zone 34 has a continuously decreasing width between the main zone 30 and the second end 28.

[0034] In the embodiment shown, the digestion corridor 12 comprises: a bottom 40; a first and a second inclined wall 42; a first and a second main wall 44; a first and a second introduction wall 46; and a first and second evacuation walls 48.

[0035] In the embodiment shown, the corridor 12 is substantially symmetrical with respect to a plane (X, Z).

[0036] The bottom 40 is substantially flat and horizontal, and extends along X between the first 26 and second 28 ends of the corridor 12. The bottom 40 is delimited along Y by a first and a second lateral edge 50, parallel to X. Said lateral edges 50 are spaced apart by a first width 52 measured along Y.

[0037] According to one embodiment, near the second end 28, the bottom 40 has a slight slope descending towards said second end. The slight slope is for example of the order of 1%.

[0038] Each of the first and second inclined walls 42 is substantially planar and extends upwardly from, respectively, the first and second lateral edges 50. Each inclined wall 42 is delimited upwardly by an end edge 54, parallel to X.

[0039] Each of the first and second inclined walls 42 is inclined relative to the vertical, by an angle α between 30° and 60°, preferably between 40° and 50°.

[0040] The first and second main walls 44 delimit the main zone 30 along X. Each of the first and second main walls 44 extends in a plane (X, Z) from the end edge 54, respectively of the first and second inclined walls 42. The first and second main walls 44 are spaced apart by a second width 56 measured along Y.

[0041] The second width 56 is greater than the first width 52. Preferably, a ratio between the second width 56 and the first width 52 is between 1.5 and 4, more preferably between 2 and 3.

[0042] The first and second introduction walls 46 delimit the introduction zone 32 along X. Each of the first and second introduction walls 46 extends in a vertical plane between the first end 26 of the corridor 12 and, respectively, the first and second main walls 44.

[0043] Each of the first and second introduction walls 46 is inclined relative to X by an angle [3 comprised between 30° and 60°, preferably comprised between 35° and 55°, more preferably comprised between 40° and 50°. Thus, the introduction zone 32 has a width which increases continuously between the first end 26 and the main zone 30.

[0044] Each of the first and second introduction walls 46 forms an oblique junction 58 with, respectively, the first and second inclined walls 42.

[0045] The first and second evacuation walls 48 delimit the evacuation zone 34 along X. Each of the first and second evacuation walls 48 extends in a plane vertical between, respectively, the first and second main walls 44, and the second end 28 of the corridor 12.

[0046] Each of the first and second discharge walls 48 is inclined relative to X by an angle y of between 30° and 60°, preferably between 35° and 55°, more preferably between 40° and 50°. Thus, the discharge zone 34 has a width which decreases continuously between the main zone 30 and the second end 28.

[0047] Each of the first and second discharge walls 48 forms an oblique junction 60 with, respectively, the first and second inclined walls 42.

[0048] Each of the first inlet 46, main 44 and outlet 48 walls has a substantially horizontal upper end, said upper ends forming a first upper edge 62 of the passage 12. Similarly, each of the second inlet 46, main 44 and outlet 48 walls has a substantially horizontal upper end, said upper ends forming a second upper edge 62 of the passage 12. With the first 26 and second 28 ends, the first and second upper edges 62 give a substantially octagonal shape to an upper part of the passage 12.

[0049] Optionally, the first and second upper edges 62 are connected to each other by reinforcements (not shown) such as tensioned straps extending along Y. Preferably, several reinforcements are distributed along the main zone 30.

[0050] Optionally, the corridor 12 further comprises watering ramps 63, for example arranged along the main walls 44.

[0051] The gas collector 14 surmounts the digestion corridor 12, so as to receive biogas released from the organic matter circulating in said corridor. More particularly, the collector 14 forms a vault 64 extending upwards the upper edges 62 of the corridor 12, so as to vertically close the space formed by said corridor.

[0052] The vault 64 preferably comprises a first wall 66, formed of a membrane impermeable to biogas. In the embodiment shown, the vault 64 further comprises a second protective wall 68, covering the first wall 66.

[0053] Preferably, the collector 14 further comprises one or more chimneys (not shown) for evacuating gas.

[0054] The introduction device 16 is arranged at the first end 26 of the corridor 12 and is intended to introduce organic matter to be digested into said corridor.

[0055] In the embodiment shown, the introduction device 16 comprises: an introduction conduit 70; a pusher 72; and preferably at least one radiator 74.

[0056] The introduction conduit extends between an inlet 76 and an outlet 78, said outlet opening onto the first end 26 of the digestion corridor. More precisely, the outlet 78 is materialized by a first opening, arranged in the vertical wall forming said first end 26. Said first opening extends from the bottom 40 of the corridor 12.

[0057] The inlet 76 is materialized by a second opening, arranged in a vertical wall of the introduction conduit 70. In the vertical direction Z, the inlet 76 is located higher than the outlet 78.

[0058] More precisely, in the embodiment shown, the introduction conduit 70 comprises: a drop portion 80, onto which the inlet 76 opens; and a deflection portion 82, opening onto the outlet 78.

[0059] The drop portion 80 extends vertically, from the inlet 76 to the deflection portion 82.

[0060] Said deflection portion is configured to introduce the organic matter into the corridor 12, via the outlet 78, according to a substantially horizontal movement.

[0061] For this purpose, the deflection portion 82 comprises a slide 84, inclined towards the first end 26 of the digestion corridor. In the embodiment shown, the slide 84 is substantially flat, inclined relative to the horizontal, for example at an angle of approximately 45°. In a variant not shown, the slide 84 has a concave curved surface.

[0062] The pusher 72 is able to move along a vertical stroke in the drop portion 80, between a high position and a low position. In the high position, visible in [Fig.l], the pusher 72 is located above the inlet 76. In the low position, the pusher 72 is located below said inlet 76.

[0063] The at least one radiator 74 is intended to heat the organic matter introduced into the corridor 12. The at least one radiator is for example arranged near the slide 84.

[0064] According to an alternative embodiment not shown, the introduction device comprises: a plurality of introduction conduits, aligned along Y at the first end of the corridor; and a plurality of pushers, each pusher equipping an introduction conduit. Said introduction conduits and said pushers are preferably similar to the introduction conduit 70 and the pusher 72 described above. Preferably, at least one of said introduction conduits is equipped with a radiator 74 as described above.

[0065] The evacuation device 18, arranged at the second end 28 of the corridor 12, is intended to evacuate the digested organic matter from said corridor.

[0066] The evacuation device 18 comprises an evacuation conduit 86 and an evacuation pump 88, arranged on said conduit.

[0067] The evacuation conduit 86 extends from an inlet 90, materialized by a third opening formed in the vertical wall forming the second end 28 of the corridor 12. Preferably, said third opening is slightly raised relative to the bottom 40 of the corridor.

[0068] Preferably, the discharge conduit comprises a conical portion 92 and a cylindrical portion 94. The conical portion is adjacent to the inlet 90 and has a decreasing diameter from said inlet to the cylindrical portion 94. The discharge pump 88 is arranged on said cylindrical portion.

[0069] Preferably, the installation 10 comprises a room 96 adjacent to the second end 28 of the corridor 12, said room 96 receiving the conical portion 92, the pump 88 and a part of the cylindrical portion 94 of the evacuation conduit.

[0070] A method of constructing the installation 10 will now be described.

[0071] An excavation 97 is first made in the ground 22, corresponding substantially to the shape of the bottom 40 and the inclined walls 42 of the corridor 12. A length along X of said excavation 97 is chosen as a function of a desired length of the corridor 12.

[0072] First prefabricated elements are inserted into the ground 22 to form a structure of the first 26 and second 28 ends, the introduction walls 46 and the evacuation walls 48 of the corridor 12.

[0073] Similarly, second prefabricated elements are arranged partially buried in the ground 22, to form the introduction conduit 70. Preferably, said introduction conduit is configured so that the second opening, forming the inlet 76, is flush with the surface 24 of the ground 22. In the embodiment shown, the first opening forming the outlet 78 is below the level of said surface 24, as is the bottom 40.

[0074] Similarly, third prefabricated elements are arranged partially buried in the ground 22, to form the room 96.

[0075] Furthermore, fourth elements 98 are arranged on the surface 24 of the floor 22 to form a structure of the main walls 44. As visible in [Fig.3], the fourth elements 98 preferably have an L-shaped section to stabilize the main walls 44 in a vertical position.

[0076] According to one embodiment, the fourth elements 98 are prefabricated, several similar elements being aligned to achieve the desired length of the corridor. According to another embodiment, the fourth elements 98 are manufactured on site by pouring concrete.

[0077] Preferably, the fourth elements 98 are integral with foundation elements (not shown), such as pads, buried in the ground 22.

[0078] The first, second, third and fourth 98 prefabricated elements are preferably made of concrete. Preferably, the first, second and third prefabricated elements have a standard size; and the fourth prefabricated elements 98 are adapted to the length according to X desired for the installation 10.

[0079] The first and fourth 98 prefabricated elements are secured to each other, so that the ends 26, 28 and the upper edges 62 form a solid belt to the corridor 12.

[0080] Next, a composite membrane 100 is applied to the excavation 97 and to the first and fourth prefabricated elements, so as to finalize the bottom 40, the inclined walls 42, the main walls 44, the introduction walls 46 and the evacuation walls 48 of the corridor 12.

[0081] The composite membrane 100 comprises for example: a layer 102 of geotextile, oriented towards the ground 22 and towards the prefabricated elements; a first layer 104 of plastic material, oriented towards the inside of the corridor 12; and an insulator 106 arranged between said layers 102 and 104. The insulator 106 is for example formed from recycled polystyrene. Preferably, the composite membrane further comprises a second layer of plastic material, interposed between the first layer 102 of geotextile and the insulator 106.

[0082] Then, the watering ramps 63 and the vault 64 of the collector are put in place; and the introduction 16 and evacuation 18 devices are installed at the corresponding locations.

[0083] A method of operating the methanization installation 10 will now be described.

[0084] First, organic matter, such as agricultural waste containing straw, is discharged into the introduction conduit 70 through the inlet 76. When the chute portion 80 is full, the pusher 72 is actuated alternately between the high position and the low position. Each time the high position is reached, a new discharge of organic matter can be carried out at the inlet 76. Under the action of the pusher, the corridor 12 is gradually filled with organic matter.

[0085] The at least one radiator 74 makes it possible to heat the organic matter before its introduction into the corridor 12, to accelerate the digestion process.

[0086] The operation of the push button 72 and of the at least one radiator 74 is for example managed by a program stored in the electronic control module 20.

[0087] The increasing width shape of the introduction zone 32 promotes a homogeneous loading of the corridor 12 with organic matter, avoiding the formation of dead zones.

[0088] Due to the physical properties mentioned above, the continuous introduction of organic matter causes said matter to move coherently along the corridor 12, in the direction X. Preferably, said organic matter is watered throughout its path, by means of the watering ramps 63, injecting water or fermentation juices into the corridor 12. The operation of the watering ramps is preferentially managed by the program of electronic module 20.

[0089] The progression of the organic matter along the digestion corridor 12, in a humid and warm environment, promotes the anaerobic decomposition of said organic matter. This results in the production of biogas which is released from the solid matter and is recovered in the vault 64 of the collector 14. Preferably, the gas is then evacuated through the chimney(s).

[0090] For information purposes, the travel time of the organic matter, between the first 26 and second 28 ends of the corridor 12, is between 40 and 60 days. The travel time depends in particular on the length along X chosen for the corridor 12.

[0091] The decreasing width shape of the evacuation zone 34 of the corridor 12 promotes the movement of organic matter towards the inlet 90 of the evacuation conduit 86.

[0092] When the digested organic matter arrives at the second end 28 of the corridor 12, it is sucked into the evacuation conduit 86 by the pump 88. The operation of said pump is preferably managed by the program of the electronic module 20.

[0093] Preferably, the digested organic matter is discharged via the conduit 86 to a phase separator and / or a digestate storage building (not shown). The liquid phase is optionally recycled by reintroduction into the corridor 12 by means of the watering ramps 63.

[0094] The methanization installation 10 according to the invention makes it possible to obtain efficient circulation of the organic matter in digestion. The flow rate of treated material is thus improved. For example, the methanization installation 10 described above makes it possible to obtain flow rates of 1000 m3 to 3000 m3 per day of biogas, for a first 52 and a second 56 width respectively of the order of 4 m and 12 m for the corridor 12.

Claims

Claims

1. Methanization installation (10), comprising: - a digestion corridor (12), capable of receiving organic matter, said corridor extending in a substantially linear manner in a horizontal longitudinal direction (X), between a first (26) and a second (28) end; - a gas collector (14), surmounting the digestion corridor; and - an introduction device (16) and an evacuation device (18) for organic matter, arranged respectively at the first and second ends of the digestion corridor; the digestion corridor comprising a main zone (30), said main zone having a substantially cylindrical surface extending in the longitudinal direction; the digestion corridor further comprising an introduction zone (32) and an evacuation zone (34);the installation being characterized in that, in a transverse direction (Y), perpendicular to the longitudinal direction: the introduction zone (32) has a continuously increasing width between the first end and the main zone; the evacuation zone (34) has a continuously decreasing width between the main zone and the second end; and at least one of the introduction zone and the evacuation zone is delimited by two first walls (46, 48) which are substantially flat and substantially vertical.;

2. Methanization installation according to claim 1, in which each of the first walls (46, 48) forms a first angle (|3, y) between 30° and 60°, preferably between 35° and 55°, more preferably between 40° and 50°, with the longitudinal direction.

3. Methanization installation according to claim 1 or 2, in which the digestion corridor (12) comprises two second walls (42) oriented upwards, each of said second walls being inclined relative to the vertical, by a second angle (a) between 30° and 60°, preferably between 40° and 50°.

4. Methanization installation according to claim 3, in which the digestion corridor (12) further comprises a substantially horizontal bottom (40), connecting the two second walls (42).

5. Methanization installation according to claim 3 or 4, in which the main zone (30) of the digestion corridor comprises two third walls (44) which are substantially vertical, each of said third walls extending upwards one of the second walls (42).

6. Methanization installation according to one of the preceding claims, in which the introduction device (16) comprises: an introduction conduit (70), opening onto the first end (26) of the digestion corridor; and a pusher (72), capable of pushing the organic matter towards said first end.

7. Methanization installation according to claim 6, in which the introduction conduit (70) comprises: a drop portion (80), extending vertically; and a deflection portion (82), configured to introduce the organic matter into the digestion corridor according to a substantially horizontal movement; the pusher being able to move according to a vertical stroke in the drop portion.

8. Method of constructing an installation according to one of claims 3 to 5, comprising the following steps: making an excavation (97) in a ground (22); and applying a membrane (100) to said excavation, so as to form the second walls (42).

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