Method for impregnating biomass and device for impregnating biomass

Abstract

The invention relates to a method for impregnating biomass (10). In a step (S100) of the method, a reactor unit (11) is fed with biomass (10) by means of a plug screw (12). In another step (S200), the reactor unit (11) is at least partially filled up to a predetermined fill level (13) with a reactant (18), such that a reaction between the fed biomass (10) and the reactant (18) takes place in order to obtain an impregnated biomass. In another step (S300), the impregnated biomass (10) is discharged from the reactor unit (11) for further processing (S300). The invention further relates to a device (1) for impregnating biomass (10).

Claims

1. A method for impregnating biomass (10), the method comprising: feeding a reactor unit (11) with biomass (10) by means of a plug screw (12, S100); conveying the biomass (10) by means of at least one conveyer screw (15) within the reactor unit (11) during impregnation of the biomass (10, S210); at least partially filling the reactor unit (11) up to a predetermined fill level (13) with a reactant (18), such that a reaction between the fed biomass (10) and the reactant (18) takes place in order to obtain an impregnated biomass (S200); controlling the fill level (13) such that it is constant over a predetermined time by regulating inflow of the reactant (18) into the reactor unit (11); determining the fill level (13) depending on the velocity with which the biomass (10) is conveyed through the reactor unit (11), wherein the velocity is regulated by rotational velocity of the conveyor screw (15); and discharging the impregnated biomass (10) from the reactor unit (11) for further processing (S300).

2. The method for impregnating biomass (10) of claim 1 further comprising compressing the biomass (10) by means of the plug screw (12) before feeding the biomass (10) into the reactor unit (11, S20).

3. The method for impregnating biomass (10) of claim 2 further comprising pre-compressing the biomass (10) by means of a force feed screw (14) before feeding the biomass (10) into the reactor unit (11, S10).

4. The method for impregnating biomass (10) of claim 2, wherein the volumetric compression ratio during compression with the plug screw (12) is between 1.5 and 6.

5. The method for impregnating biomass (10) of claim 4, wherein the volumetric compression ratio during compression with the plug screw (12) is between 1.7 and 3.

6. The method for impregnating biomass (10) of claim 4, wherein the volumetric compression ratio during compression with the plug screw (12) is about 1.9.

7. The method for impregnating biomass (10) according to claim 1 further comprising removing residual reactant (18) from the impregnated biomass (10) in a further processing step (S400) following the discharge (S300) of the impregnated biomass (10) out of the reactor unit (11); supplying the residual reactant (18) into a recirculation circuit (17); and providing the reactant (18) to be filled into the reactor unit (11) from the recirculation circuit (17) and/or from a reservoir (16).

8. The method for impregnating biomass (10) according to claim 1 further comprising controlling a constant fill level (13) of the reactant (18) within the reactor unit (11) such that the biomass (10) can be homogeneously impregnated during a specified impregnation time.

9. The method for impregnating biomass (10) according to claim 1 further comprising controlling an amount of reactant (18) filled into the reactor unit (11) in dependence on a pH-value of the impregnated biomass (10) discharged from the reactor unit (11) and/or on a pH-value of the reactant (18) filled into the reactor unit (11).

10. The method for impregnating biomass (10) according to claim 1 further comprising controlling a temperature and/or a pressure to be provided within the reactor unit (11) during impregnation (S230).

11. The method for impregnating biomass (10) according to claim 1 further comprising feeding the reactor unit (11) by means of a plug screw (12) in a first direction before conveying the biomass (10) along a longitudinal axis of the reactor unit (11) during impregnation, the longitudinal axis (22) being substantially perpendicular to the first direction, wherein a ratio between an extension of the reactor unit (11) along the longitudinal axis (22) and a width of the reactor unit (11) is at least 2.

12. The method for impregnating biomass (10) according to claim 1 further comprising interrupting the feed of biomass (10) into the reactor unit (11) by means of a retaining member (23) that is arranged upstream of the reactor unit (11, S110).

13. The method for impregnating biomass (10) according to claim 1, wherein the reactant is a liquid comprising chemicals selected from the group consisting of an acid, a catalyst or mixtures thereof.

14. A device (1) for impregnating biomass (10), the device comprising: a compression unit (40) having an outlet; and a reactor unit (11) having an inlet; wherein: the outlet of the compression unit (40) is connected to the inlet of the reactor unit (11); the compression unit (40) comprises a plug screw (12) which is configured for feeding the biomass (10) into the reactor unit (11); the reactor unit (11) is configured for being at least partially filled with a reactant (18) up to a predetermined fill level (13) such that a homogeneous impregnation of the fed biomass (10) takes place when the biomass (10) is conveyed within the reactor unit (11) by means of conveyor screw (15); the reactor unit (11) is configured for controlling the fill level (13) such that it is constant over a predetermined time by regulating inflow of a reactant (18) into the reactor unit (11); and the reactor unit (11) is configured for determining the fill level (13) depending on the velocity with which the biomass (10) is conveyed through the reactor unit (11)), wherein the velocity is regulated by rotational velocity of the conveyor screw (15).

15. The device (1) for impregnating biomass (10) of claim 14, wherein the reactor unit (11) is at least partially manufactured of a material that is resistant to corrosion.

16. The device (1) for impregnating biomass (10) of claim 14, wherein the plug screw (12) of the compression unit (40) is configured for feeding the biomass (10) into the reactor unit (11) in a first direction (30); and wherein the conveyor means (15) of the reactor unit (11) is configured for conveying the biomass (10) within the reactor unit (11) along a longitudinal axis (22) of the reactor unit (11), the longitudinal axis (22) being substantially perpendicular to the first direction (30).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a device for impregnating biomass, according to an embodiment of the invention.

(2) FIG. 2 shows a detailed view of a compression unit and a reactor unit of a device for impregnating biomass, according to an embodiment of the invention.

(3) FIG. 3 shows a device for impregnating biomass as well as a further processing step after impregnating the biomass, according to an embodiment of the invention.

(4) FIG. 4 shows a flow diagram of a method for impregnating biomass, according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(5) FIG. 1 shows a device 1 for impregnating biomass 10. The device 1 comprises a compression unit 40 of which FIG. 2 shows a detailed view. The compression unit 40 comprises a plug screw 12, wherein the plug screw 12 of the compression unit 40 is configured for feeding the biomass 10 into a reactor unit 11. The device 1 for impregnating biomass 10 further comprises the reactor unit 11 with a conveyor means 15, which is not visible in FIG. 1. In particular, the conveyor means 15 of the reactor unit 11 as well as the plug screw 12 of the compression unit 40 are not visible, since these elements are located inside the reactor unit 11 and the compression unit 40, respectively. However, the detailed view of FIG. 2 shows both the plug screw 12 and the conveyor means 15. In a preferred embodiment, two conveyor screws 15 are integrated into the reactor unit 11.

(6) The reactor unit 11 may be at least partially filled with a reactant 18 to a predetermined fill level 13, wherein the reactant 18 is also not visible in FIG. 1, as it is located inside the reactor unit 11. The reactor unit 11 is at least partially manufactured of a material that is resistant to corrosion. For example, a lower part or a bottom part of the reactor unit 11 which is located near the compression unit 40 is made of a corrosion-resistant material, whereas an upper part which is near a discharge 27 of the reactor unit 11 may be manufactured of another material. The plug screw 12 of the compression unit 40 is configured for feeding the biomass 10 into the reactor unit 11 in a first direction 30, which may for instance be parallel to an Earth's surface. The conveyor means 15 of the reactor unit 11 is configured for conveying the biomass 10 within the reactor unit 11 along a longitudinal axis 22 of the reactor unit 11, which is substantially perpendicular to the first direction 30. In other words, the reactor unit 11 is arranged substantially vertical with respect to the Earth's surface which will be described in more detail in FIG. 3.

(7) FIG. 2 shows a detailed view of at least a part of the compression unit 40, and at least a part of the reactor unit 11, wherein inner parts of both components are visible. In particular, the compression unit 40 comprises a plug screw 12 for feeding the reactor unit 11 with biomass 10 in the first direction 30. In particular, the compression of the biomass 10 by means of the plug screw 12 is conducted before feeding the biomass 10 into the reactor unit 11. Furthermore, a force-feed screw 14, which is not shown in FIG. 2, can also be integrated into the compression unit such that a pre-compressing of biomass 10 can be provided. The pre-compression of the biomass 10 by means of the force-feed screw 14 may be conducted before compressing the biomass 10 by means of the plug screw 12, and therefore also before feeding the biomass 10 into the reactor unit 11. The compression of the biomass 10 may lead to a plug 10a of biomass 10 at the end of the plug screw 12 in the plug pipe and before the inlet into the reactor unit 11. Between the inlet into the reactor unit 11 and the plug screw 12 of the compression unit 40, a retaining member 23 may be located in order to support the compression before feeding the biomass 10 into the reactor unit 11 as well as for sealing the reactor unit 11 from the compression unit 40. A drive 24 may be provided in order to control the position of the retaining member 23 which, for instance, is a damper. In particular, the pressure applied on the incoming plug and/or the position of the blow back damper may be controlled. The damper may thus further compress the plug in the plug pipe due to the pressure applied by the damper and due to the friction in the plug pipe.

(8) The reactor unit 11 is filled with a reactant 18 to a predetermined fill level 13. The reactant 18 may be filled into the reactor unit 11 via inlets 20 at certain positions at the reactor unit 11. Some inlet positions are shown in FIG. 2. The inlet 20 may be located below the cone in which the retaining member is arranged. The inlet 20 may also be integrated into a side wall or a bottom end of the reactor unit 11. The inlet positions shown in FIG. 2 can be provided in an alternative manner but it is also possible that more than one of these inlet positions are provided. The reactor unit 11 may be formed as a container or a pipe with an elongated shape as shown in FIG. 1. The reactor unit 11 is at least partially filled with the reactant 18 to a predetermined fill level 13. Due to the vertical arrangement of the reactor unit 11 and the feeding of the biomass 10 into the reactor unit 11 combined with the predetermined fill level 13, an impregnation of the whole biomass 10 entering the reactor unit 11 can be achieved without the biomass 10 being bypassed by the reactant 18. Besides the improved impregnation characteristics that can be achieved by such a device 1, the impregnation time can also be reduced substantially.

(9) Within the reactor unit 11, the biomass 10 is conveyed by means of at least one conveyor means 15, wherein the conveyor means 15 is for example a conveyor screw. Preferably, two conveyor screws are arranged within the reactor unit 11, in order to convey the biomass 10 upwards along the longitudinal direction 31 or along the longitudinal axis 22 of the reactor unit 11 during the impregnation of the biomass 10. Below the predetermined fill level 13, the biomass 10 is impregnated with the reactant 18, and above the predetermined fill level 13, a dewatering of the biomass 10 may take place. However, the biomass 10 which is impregnated in the reactor unit 11, is transferred to an upper part of the reactor unit 11 along the longitudinal direction 31, such that the impregnated biomass 10 is discharged at the discharge 27 of the reactor unit 11 for further processing. The longitudinal direction 31 of the reactor unit 11 or the longitudinal axis 22 of the reactor unit 11 is arranged substantially perpendicular to the first direction 30, and therefore the longitudinal axis 22 of the reactor unit 11 is substantially vertical to the Earth's surface which is not shown in FIGS. 1 and 2.

(10) FIG. 3 shows the compression unit 40, the reactor unit 11, as well as a further processing step 400. The further processing step 400, which follows the discharge of the impregnated biomass at the discharge 27 of the reactor unit 11, may comprise several steps. Such steps are for example a hydrolysis step, a dewatering step, etc. FIG. 3 also shows the implementation of the device 1 for impregnating biomass 10 as well as the further processing step S400 within an environment, for example with respect to the Earth's surface 60. The reactor unit 11 is arranged substantially vertical with respect to the Earth's surface 60, whereas the feed of the reactor unit 11 by means of the plug screw 12 in the compression unit 40 is conducted in a first direction 30, which is substantially parallel to the Earth's surface 60. The reactant 18 to be filled into the reactor unit 11 is supplied from a reservoir 16, and/or via a recirculation circuit 17, which originates in the further processing step S400. In order to adjust the reactant amount, the reactant 18 may be added directly from the recirculation circuit 17 or through the reservoir 16 into the reactor unit 11. In addition to the recirculated reactant 18, fresh reactant 18 can be provided via a conduit 19. The recirculation circuit 17 may be divided into two parts. In a first part, reactant 18 or filtrate from the further processing step S400 is supplied to the tank 17c via a first conduit 17a. In a second part of the recirculation circuit 17, the reactant 18 or filtrate which is stored in the tank 17c, can be supplied via a second conduit 17b to the reactor unit 11. Within the second conduit 17b, another conduit 19 for fresh reactant 18 can be connected. In this manner, it is possible to provide a mixture of fresh reactant 18 and recirculated reactant 18, which has already been used for impregnation in the reactor unit 11. The recirculated reactant 18 can be filtered into separate particles and liquid reactant before recirculation. The solid phase could be for example added to the material feed in the region of the plug screw.

(11) FIG. 4 shows a flow diagram for impregnating biomass 10. In a step of the method S10, a pre-compression of the biomass 10 is conducted by means of a force-feed screw 14 before feeding the biomass 10 into the reactor unit 11. In another step S20 of the method, a compression of the biomass by means of a plug screw 12 is conducted before feeding the biomass 10 into the reactor unit 11. The pre-compression by means of the force feed screw 14 as well as the compression by means of the plug screw 12 may be conducted in a combined manner. However, it is possible that only a compression by means of the plug screw 12 is conducted. In another step of the method S100, the reactor unit 11 is fed with biomass 10 by means of the plug screw 12. In another step of the method S110, an interruption of the feed of biomass 10 into the reactor unit 11 is conducted by means of a retaining member 23 that is arranged upstream of the reactor unit 11. In another step of the method S200, the reactor unit 11 is at least partially filled to a predetermined fill level 13 with a reactant 18, such that a reaction between the fed biomass 10 and the reactant 18 takes place in order to obtain an impregnated biomass. In another step S210, the biomass 10 is conveyed by means of at least one conveyor means 15 within the reactor unit 11 during impregnation of the biomass 10. In another step S220, an amount of reactant 18 filled into the reactor unit 11 is adapted in dependence on a pH-value of the biomass 10 and/or in dependence on an amount of biomass 10 fed into the reactor unit 11. In another step S230 of the method, a temperature and/or a pressure to be provided within the reactor unit 11 during impregnation is controlled. In another step of the method S300, the impregnated biomass from the reactor unit 11 is discharged for further processing, for example into a further processing step S400.

(12) While the invention has been illustrated and described in detail in the drawings and the foregoing description, such illustration and description are to be considered illustrative and exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art and practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims the term “comprising” does not exclude other elements, and the indefinite article “a” or “an” does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting the scope of protection.