Search

EP-4741569-A1 - PLANT FOR PROCESSING FIBROUS MATERIAL AND OPERATING METHOD FOR THE SAME

EP4741569A1EP 4741569 A1EP4741569 A1EP 4741569A1EP-4741569-A1

Abstract

Plant for processing fibrous material and operating method for the same, wherein steam is returned by means of a pump device (500) from a steam outlet (430) of a fiber separator (400) via a steam return line (600) to a refiner-fiber separator connecting line (700) in order to support the discharge of a fiberized fibrous material from a refiner (300) and/or the transport of the fiberized fibrous material via the refiner-fiber separator connecting line (700) to the fiber separator (400).

Inventors

  • SEIDL, Clemens
  • OSTERMANN, Bernhard

Assignees

  • Andritz AG

Dates

Publication Date
20260513
Application Date
20250305

Claims (15)

  1. Plant for processing fiber material, comprising - a refiner (300) which has a fiber material inlet (310) through which fiber material, optionally softened fiber material, can be received, and a refiner outlet (320) through which fiber material refined by the refiner (300) can be discharged as a fiber material-steam mixture, - a fiber separator (400) which is downstream of the refiner (300) and which has a mixing inlet (410) for receiving the fiber material-vapor mixture, a fiber material outlet (420) for discharging fiber material separated by the fiber separator (400) from the fiber separator (400) and a steam outlet (430) through which steam can be discharged from the fiber separator (400), - a refiner-fiber separator connecting line (700) which is connected to the refiner outlet (320) via a refiner connection point (710) and to the mixing inlet (410) via a fiber separator connection point (720) and through which the fiber material-vapor mixture can be supplied from the refiner (300) to the fiber separator (400), and - a steam return line (600) which is connected on one side to the steam outlet (430) of the fiber separator (400) and on the other side to the refiner-fiber separator connecting line (700), so that a steam return loop is formed, through which steam discharged from the steam outlet (430) of the fiber separator (400) can be returned along a steam loop circulation direction (A) to the refiner-fiber separator connecting line (700), wherein the refiner connection point (710) is arranged in or at least adjacent to the steam return loop, and - a pump device (500) which is arranged in the steam recirculation loop, optionally in the steam recirculation line (600) and which is configured to pump the steam recirculated via the steam recirculation loop along the steam loop circulation direction (A).
  2. The system according to claim 1, wherein the refiner (300) comprises a grinding chamber (340) which is connected between the fiber material inlet (310) and the refiner outlet (320), and a grinding mechanism arranged in the grinding chamber (340) for The refiner (300) is integrated into the steam recirculation loop, the refiner (300) having a refiner steam inlet (330) which communicates with the grinding chamber (340) of the refiner (300) and with which the steam recirculation line (600) is connected, so that the steam discharged via the steam outlet (430) of the fiber separator (400) can be recirculated via the steam recirculation line (600) to the grinding chamber (340) of the refiner (300) to assist in the discharge of the fiberized material from the refiner (300).
  3. The system according to claim 1 or 2, wherein the pump device (500) is integrated into the refiner (300).
  4. The system according to claim 3, wherein the grinding mechanism comprises a grinding element (350) rotatable about a grinding axis (M), optionally a grinding disc rotatable about the grinding axis (M), which is also designed as a rotatable pump impeller of the pump device (500).
  5. The system according to claim 4, wherein the grinding element (350) has a grinding side (351) which has a grinding surface designed for grinding the fibrous material, and a pumping side (352) opposite the grinding side (351) which is equipped with projections (500) suitable for pumping, optionally with pump vanes.
  6. The system according to claim 5, wherein the grinding mechanism has a further, optionally a stationary, grinding element (360) which is arranged opposite the rotatable grinding element (350) such that a grinding gap (355) is formed between them, which defines a grinding gap plane (E), and wherein the refiner steam inlet (330) is arranged in or adjacent to the grinding gap plane (E) and is aligned parallel to the grinding gap plane (E) and radially or tangentially to the grinding axis of rotation (M).
  7. The system according to claim 5, wherein the refiner steam inlet (330) is aligned with respect to the grinding axis (M) at an angle of 0° to less than 90° to the pump side (352).
  8. Device according to any of the preceding claims, further comprising - a cooker (200) which is connected upstream of the refiner (300) to soften the fiber material via steam pressure, - another steam return line (800), -- which communicates with the steam outlet (430) of the fiber separator (400), with the further steam return line (800) optionally branching off from the steam return line (600), optionally in a section between the steam outlet (430) of the fiber separator (400) and the refiner (300), and -- which is connected to the cooker (200) in order to return the steam discharged from the steam outlet (430) of the fiber separator (400) to the cooker (200), wherein the cooker (200), the refiner (300), the fiber separator (400), the refiner-fiber separator connecting line (700), the vapor recirculation loop and the further vapor recirculation line (800) form a high-pressure section (H) in which an operating pressure is higher than an operating pressure upstream of a cooker inlet (210) of the cooker (200) and downstream of the fiber material outlet (420) of the fiber separator (400).
  9. A system according to any one of claims 1 to 7, further comprising - a cooker (200) which is connected upstream of the refiner (300) to soften the fiber material via steam pressure, - a cooker-refiner connecting line (1100) which connects the cooker (200) to the fiber material inlet (310) of the refiner (300), - a pressure range discharge device (1101) arranged in the boiler-refiner connecting line (1100), wherein the boiler (200) and a section of the boiler-refiner connecting line (1100) upstream of the pressure range discharge device (1101) form a high-pressure section (H) in which an operating pressure is greater than an operating pressure in a section of the boiler-refiner connecting line (1100) between the pressure range discharge device (1101) and the refiner (300), wherein optionally an operating pressure in the vapor recirculation loop is greater than the operating pressure in the section of the boiler-refiner connecting line (1100) between the pressure area discharge unit (1101) and the refiner (300).
  10. System according to claim 8 or 9, further comprising - a pre-steaming device (100) for pre-steaming fibrous material, optionally wood material, which is connected upstream of the cooker (200) in order to supply pre-steamed fibrous material to the cooker (200), wherein the pre-steaming device (100) is not part of the high-pressure section (H).
  11. Device according to any of the preceding claims, further comprising - a pulper (1000) connected to the fiber separator (400) to receive fiber material discharged from the fiber separator (400) and to disperse this fiber material in a liquid, optionally water.
  12. Operating method for the plant according to any of the preceding claims, wherein steam is returned from the steam outlet (430) of the fiber separator (400) via the steam return line (600) to the refiner-fiber separator connecting line (700) by means of the pump device (500) to support the discharge of the fiberized fiber material from the refiner (300) and/or the transport of the fiberized fiber material via the refiner-fiber separator connecting line (700) to the fiber separator (400).
  13. Operating method according to claim 12, wherein the fiber separator (400) is designed as a cyclone separator and wherein the fiberized material is accelerated to a speed sufficient to form a cyclone in the cyclone separator by means of the pump device (500) by returning the steam to the refiner-fiber separator connecting line (700).
  14. Use of the plant according to any of claims 1 to 11 or of the operating method according to claim 12 or 13 for recycling medium-density fiberboard.
  15. Use of the plant according to any of claims 1 to 11 or of the operating method according to claim 12 or 13 for producing lignocellulosic fibers for substrate.

Description

The invention relates to a plant for processing fibrous material and to an operating method of a plant as described in this application. Currently, in the processing of fibrous material, the fiber material is broken down into fibers by a refiner and then discharged from the refiner with a large amount of steam. This high volume of steam at least assists the transport of the broken-down fiber material, as a fiber-steam mixture, from the refiner to a fiber separator. The fiber separator then separates the broken-down fiber material from the fiber-steam mixture, and the steam can be discharged from the separator via a steam outlet. Such a device is, for example, from the... WO 2015/014451 A1 known. The object of the invention is to create a plant for processing fibrous material which requires less energy for its operation, as well as an operating method for such a plant and a use of such a plant or such an operating method. The invention provides a system for processing fiber material according to claim 1, an operating method according to claim 12, a use according to claim 14, and a use according to claim 15. Advantageous embodiments of the invention are described in the dependent claims. The steam return line and the pump device located in the steam return loop allow steam from the fiber separator's steam outlet to be returned to the refiner connection point of the refiner-fiber separator connecting line. This enables, among other things, improved (e.g., energy-saving and/or resource-conserving) support for transporting the fiber material-steam mixture from the refiner, even in cases where little steam is generated in the refiner due to less frictional heat during the fiberization process. This applies, for example, to applications in the recycling of medium-density fibers. Wood fiberboard (MDF) in the form of post-consumer waste fiber material is used because, when MDF is used as raw material, the fiber material is not as densely packed in the process state before the refiner as with solid wood-based raw material or other wood raw material being fiberized for the first time. Consequently, less energy is required in an MDF recycling process for fiberizing the raw material compared to fiber that has not been previously fiberized. With less energy required, less frictional heat is generated, and therefore less steam is needed in the refiner to transport the fiber-steam mixture out of the refiner. As a result, the steam recirculated to the refiner can at least assist in transporting the fiber material out of the refiner as a fiber-steam mixture, reducing or eliminating the need to generate fresh steam elsewhere and introduce it to transport the fiber material to the fiber separator. Furthermore, by recirculating the steam from the fiber separator to the refiner, the amount of steam loss is kept to a minimum, and steam cleaning is only required for a smaller amount of steam or is even avoided entirely. Thus, the system according to the invention requires less energy; for example, less energy is needed to generate additional fresh steam and/or less energy is needed for steam cleaning. In contrast to plants for processing fiber material without a refiner, the use of a refiner leads to an improved dissolution effect and reduced evaporation, and allows for both a design for carrying out a wet process and a design for carrying out a dry process. Optionally, the refiner connection point of the refiner-fiber separator connecting line can be located in or at least adjacent to the steam recirculation loop. The refiner can, for example, include a grinding chamber located between the fiber material inlet and the refiner outlet, and a grinding mechanism arranged within the grinding chamber for grinding the received fiber material. The refiner can be integrated into the steam recirculation loop and may have a refiner steam inlet that communicates with the refiner's grinding chamber and is connected to the steam recirculation line. This allows the steam discharged from the fiber separator's steam outlet to be recirculated back to the refiner's grinding chamber via the steam recirculation line, thus aiding the discharge of the fiberized material from the refiner. This improves and simultaneously increases the efficiency of transporting the fiberized material, as a fiber-steam mixture, from the refiner to the refiner-fiber separator connecting line and onward to the fiber separator. The pump device can be integrated into the refiner, making the system more compact. The grinding mechanism can include a grinding element rotatable around a grinding axis, or optionally a grinding disc rotatable around the same axis, which also serves as the rotatable impeller of the pumping device. By designing the grinding element as a rotatable impeller, it can perform a dual function, resulting in an even more compact design. Simultaneously, less energy is required because no additional part needs to be moved for pumping; instead, the rotating g