METHOD AND PROCESSING SYSTEM FOR REDUCING VOLATILE ORGANIC COMPOUNDS FROM WOOD CHIPS

Abstract

The disclosure relates to a method for reducing volatile organic compounds (VOC) from wood chips for wood fibre production in a processing system, at least comprising the following consecutive steps: a first thermal treatment of the wood chips in a first thermal treatment device, which is designed to receive VOC-containing waste gases; cleaning the wood chips in a washing device; a second thermal treatment of the wood chips in a second thermal treatment device, which is designed to receive and separate VOC-containing waste gases; digesting the wood chips in a digester, which is designed to receive and separate VOC-containing waste gases; and crushing the wood chips in a refiner, which is designed to separate VOC-containing waste gases. This allows for an efficient, and thus energy-optimised or environmentally friendly and therefore also cost-optimised reduction of volatile organic compounds from wood chips.

Claims

1. A method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production in a processing system, comprising at least the following successive steps: first thermal treatment of the wood chips in a first thermal treatment device adapted to receive exhaust gases containing VOCs; cleaning of the wood chips in a washing device; second thermal treatment of the wood chips in a second thermal treatment device which is designed to receive and separate exhaust gases containing VOCs; cooking the wood chips in a digester adapted to receive and remove VOC-containing flue gases; and crushing the wood chips in a refiner adapted to remove VOC-containing exhaust gases.

2. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the first thermal treatment device is designed to receive exhaust gases containing VOCs, which are separated from the second thermal treatment device, the digester and/or the refiner.

3. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the second thermal treatment device is adapted to receive VOC-containing exhaust gases which are discharged from the digester and/or the refiner.

4. The method for reducing volatile organic compounds, VOCs, from wood chips for wood fibre production according to claim 1, wherein the VOCs are discharged from the processing system from the first thermal treatment device, the second thermal treatment device, the digester and/or the refiner.

5. The method for reducing volatile organic compounds, VOCs, from wood chips for wood fibre production according to claim 1, wherein the VOCs from the processing system are discharged from the washing device and/or that the processing system comprises a stuffing screw along a material flow between the second thermal treatment device and the digester, wherein the VOCs from the processing system are discharged from the stuffing screw and/or that the processing system comprises a discharge screw along a material flow between the digester and the refiner, wherein the VOCs from the processing system are discharged from the discharge screw.

6. The method for reducing volatile organic compounds, VOCs, from wood chips for wood fibre production according to claim 1, wherein the first thermal treatment of the wood chips is carried out at 80 degrees Celsius for 5 to 10 minutes; and/or the second thermal treatment of the wood chips is carried out at 100 degrees Celsius for 5 to 10 minutes; and/or cooking the wood chips between 140 to 180 degrees Celsius for 2 to 5 minutes.

7. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the first thermal treatment device is heated at least partially, preferably completely, by exhaust vapours from the digester.

8. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the exhaust gases containing VOCs from the digester and the refiner and optionally also from the second thermal treatment device are passed on together.

9. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the digester is designed to receive VOC-containing exhaust gases, which are separated from the digester and/or the refiner.

10. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the exhaust gases containing VOCs are introduced into a bottom section of the digester, the first and/or the second thermal treatment device.

11. The method for reducing volatile organic compounds, VOC, from wood chips for wood fibre production according to claim 1, wherein the material flow of the wood chips is from the first thermal treatment device into the washing device; from the washing device into the second thermal treatment device; from the second thermal treatment device into the cooker; and from the cooker into the refiner.

12. A processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production for performing a process according to claim 1, comprising: a first thermal treatment device adapted to receive VOC-containing exhaust gases for first thermal treatment of the wood chips; a washing device for cleaning the wood chips; a second thermal treatment device adapted to receive and extract VOC-containing exhaust gases for the second thermal treatment of the wood chips; a cooker adapted to receive and discharge VOC-containing exhaust gases for cooking the wood chips; and a refiner adapted to remove VOC-containing exhaust gases for comminuting the wood chips.

13. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein said processing system comprises a duct system with duct sections, said duct sections being arranged and configured to transfer VOC-containing exhaust gases discharged from said second thermal treatment device, said digester and/or said refiner to said first thermal treatment device.

14. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a duct system with duct sections, the duct sections being arranged and formed to pass VOC-containing exhaust gases discharged from the digester and/or the refiner to the second thermal treatment device.

15. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a conduit system with conduit sections, the conduit sections being arranged and configured to discharge the VOCs from the first thermal treatment device, the second thermal treatment device, the digester and/or the refiner.

16. The processing system for reducing volatile organic compounds, VOCs, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a conduit system with conduit sections, the conduit sections being arranged and configured to discharge VOCs from the washing device and/or that the processing system comprises a stuffing screw along a material flow between the second thermal treatment device and the digester, wherein the VOCs can be discharged from the processing system from the stuffing screw via line sections of the line system and/or that the processing system has a discharge screw along a material flow between the digester and the refiner, it being possible for the VOCs to be discharged from the processing system out of the discharge screw via line sections of the line system.

17. The processing system for reducing volatile organic compounds, VOCs, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a heating system with heating medium line sections, wherein the heating medium line sections are arranged and formed to heat the first thermal treatment device at least partially, preferably completely, via exhaust vapours from the digester.

18. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a pipe system with pipe sections, the pipe sections being arranged and formed to convey the VOC-containing exhaust gases of the digester, the refiner and optionally the second thermal treatment device in a combined manner.

19. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a duct system with duct sections, wherein the digester and the duct sections are arranged and formed to introduce VOC-containing exhaust gases discharged from the digester and/or the refiner into the digester.

20. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the digester comprises a bottom portion adapted to receive VOC-containing exhaust gases from the digester, the first and/or the second thermal treatment device via duct portions of a duct system.

21. The processing system for reducing volatile organic compounds, VOC, from wood chips for wood fibre production, according to claim 12, wherein the processing system comprises a wood chip material flow system with material flow lines, wherein the material flow lines for a material flow of the wood chips are arranged between: the first thermal treatment device and the washing device; the washing device and the second thermal treatment device; the second thermal treatment device and the cooker; and the cooker and the refiner.

Description

DRAWINGS

[0078] The drawing described herein is for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

[0079] In the following, the disclosure is explained exemplarily with reference to the accompanying drawing based on the preferred exemplary embodiments, wherein the features shown below both individually and in combination may repre-sent an aspect of the disclosure. In the drawing:

[0080] FIG. 1 shows a method for reducing volatile organic compounds from wood chips for wood fiber production in a processing system, with representation of the material flow and the exhaust gas flow.

DETAILED DESCRIPTION

[0081] Example embodiments will now be described more fully with reference to the accompanying drawing.

[0082] FIG. 1 shows a schematic illustration of a processing system 1 for carrying out a method for reducing volatile organic compounds, VOCs, from wood chips for wood fiber production.

[0083] Structurally, the processing system 1 comprises at least a first thermal treatment device 10, a washing device 20, a second thermal treatment device 30, a digester 40 and a refiner 50.

[0084] In this regard, the processing system 1 for reducing VOCs from wood chips according to FIG. 1 performs the following process steps:

[0085] In the first thermal treatment device 10 a first thermal treatment of wood chips 100 is carried out.

[0086] Subsequently, in the washing device 20 a cleaning of the wood chips 200 takes place.

[0087] After the cleaning of the wood chips 200, they are thermally treated 300 a second time in the second thermal treatment device 30.

[0088] The wood chips that have been thermally treated 300 the second time in the second thermal treatment device 30 are subsequently cooked 400 in the digester 40. [0089] cooked.

[0090] After the cooking of the wood chips 400 in the digester 40, the wood chips are crushed 500 in the refiner 50.

[0091] Within the processing system 1, for the energy-efficient and environmentally friendly reduction of VOCs from wood chips according to FIG. 1 a gas flow as follows occurs:

[0092] By use of the first thermal treatment device 10 VOC-containing exhaust gases G1 are received.

[0093] By use of the second thermal treatment device 30, VOC-containing exhaust gases G2 are received.

[0094] Furthermore, the second thermal treatment device 30 discharges VOC-containing exhaust gases G3.

[0095] The digester 40 receives VOC-containing exhaust gases G4. Furthermore, the digester 40 discharges VOC-containing exhaust gases G5.

[0096] The refiner 50 is at least configured to discharge VOC-containing exhaust gases G6. Optionally a reception of VOC-containing exhaust gases from the digester 40 is possible.

[0097] The chips which release VOCs follow a material flow within the processing system as follows:

[0098] From the first thermal treatment device 10 into the washing device 20 M1, from the washing device 20 into the second thermal treatment device 30 M2, from the second thermal treatment device 30 into the digester 40 M3, and from the digester 40 into the refiner 50 M4.

[0099] Stated differently, the processing system 1 for reducing volatile organic compounds, VOC, from wood chips for wood fiber production for carrying out the aforementioned process comprises: [0100] a first thermal treatment device 10, configured to receive VOC-containing exhaust gases G1 for a first thermal treatment of the wood chips 100; [0101] a washing device 20 for cleaning the wood chips 200; [0102] a second thermal treatment device 30, configured to receive G2 and discharge G3 VOC-containing exhaust gases for a second thermal treatment of the wood chips 300; [0103] a digester 40 configured to receive G4 and discharge G5 VOC-containing exhaust gases for cooking the wood chips 400; and [0104] a refiner 50 configured to discharge VOC-containing exhaust gases G6, for crushing the wood chips 500.

[0105] The method for reducing volatile organic compounds, VOCs, from wood chips for wood fiber production in a processing system 1, comprises, in other words, at least the following successive steps: [0106] first thermal treatment of the wood chips 100 in a first thermal treatment device 10, configured to receive G1 VOC-containing exhaust gases; [0107] cleaning the wood chips 200 in a washing device 20; [0108] second thermal treatment of the wood chips 300 in a second thermal treatment device 30 configured to receive G2 and discharge G3 VOC-containing exhaust gases; [0109] cooking the wood chips 400 in a digester 40 configured to receive G4 and discharge G5 VOC-containing exhaust gases; and [0110] crushing the wood chips 500 in a refiner 50 configured to discharge G6 VOC-containing exhaust gases.

[0111] According to a preferred embodiment of the disclosure according to FIG. 1 it is provided that the first thermal treatment device 10 is configured to receive G1 VOC-containing exhaust gases, which are discharged from the second thermal treatment device 30 G3, the digester 40 G5 and the refiner 50 G6.

[0112] According to a preferred embodiment of the disclosure, it is provided according to FIG. 1 that the second thermal treatment device 30 is configured to receive G2 VOC-containing exhaust gases, which are discharged from the digester 40 G5 and the refiner 50 G6.

[0113] According to a preferred embodiment of the disclosure it is provided that the VOCs are discharged from the first thermal treatment device 10, the second thermal treatment device 30, the digester 40 and/or the refiner 50. This is not shown in greater detail in FIG. 1.

[0114] According to a preferred embodiment of the disclosure it is provided that the processing system 1 preferably comprises a stuffing screw along a material flow between the second thermal treatment device 30 and the digester 40, wherein the VOCs are discharged from the processing system 1, in particular from the washing device M2X and/or in particular from the stuffing screw M3X. Further optionally or additionally provided is that the processing system 1 comprises a discharge screw along a material flow between the digester 40 and the refiner 50, wherein the VOCs from the processing system 1 are discharged M4X from the discharge screw. The discharge screw can be designed as a stuffing screw.

[0115] According to a preferred embodiment of the disclosure it is provided that the first thermal treatment of the wood chips 100 is carried out at 80 degrees Celsius for 5 to 10 minutes; and/or the second thermal treatment of the wood chips 300 is carried out at 100 degrees Celsius for 5 to 10 minutes; and/or the cooking of the wood chips 400 is carried out between 140 to 180 degrees Celsius for 2 to 5 minutes; both the temperature data as well as the time data preferably include a respective deviation upwards and/or downwards of 10 percent inclusive.

[0116] According to a preferred embodiment of the disclosure, it is provided that the first thermal treatment device 10 is heated at least partially, preferably completely, by exhaust gases from the digester 40.

[0117] According to a preferred embodiment of the disclosure, it is provided according to FIG. 1 that the VOC-containing exhaust gases from the digester 40 and the refiner 50 are forwarded in a combined manner.

[0118] According to a preferred embodiment of the disclosure according to FIG. 1, it is further provided that the VOC-containing exhaust gases of the second thermal treatment device 30, the digester 40 and the refiner 50 are forwarded in a combined manner.

[0119] According to a preferred embodiment of the disclosure according to FIG. 1, it is provided that the digester 40 is configured to receive VOC-containing exhaust gases G4, which are discharged from the digester 40 G5 and the refiner 50 G6.

[0120] According to a preferred embodiment of the disclosure according to FIG. 1, it is provided that the VOC-containing exhaust gases are introduced into a bottom section of the digester 40, the first and the second thermal treatment device 10, 30.

[0121] According to a preferred embodiment of the disclosure according to FIG. 1, it is provided that the material flow of the wood chips occurs [0122] from the first thermal treatment device 10 into the washing device 20 M1; [0123] the washing device 20 into the second thermal treatment device 30 M2; [0124] the second thermal treatment device 30 into the digester 40 M3; and [0125] the digester 40 into the refiner 50 M4.

[0126] The foregoing description of the embodiment has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.