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CA-3059151-C - REACTION DEVICE WITH HEAT EXCHANGER AND USE THEREOF

CA3059151CCA 3059151 CCA3059151 CCA 3059151CCA-3059151-C

Abstract

The invention relates to a reaction device (1) with a first wall (2) that defines an interior (3) in which a stirring mechanism (4) is located. A heat exchanger (5) is at least partly provided on the first outer wall (2) surface facing away from the interior (3) and/or on the stirring mechanism (4), wherein the heat exchanger (5) has a grate structure, and at least two layers are provided which have a grate structure. Thus, it is possible to transfer heat in a precise and efficient manner primarily by means of thermal radiation in endothermic processes at different temperature levels, in particular pyrolysis, gassing, and reforming processes, and thereby use the exhaust heat for other processes.

Inventors

  • Andreas Hornung
  • Jonathan Aigner
  • Peter Hense
  • Alberto Pedrazzini
  • THORSTEN HORNUNG

Assignees

  • FRAUNHOFER-GESELLSCHAFT ZUR FOERDERUNG DER ANGEWANDTEN FORSCHUNG E.V.
  • SUSTEEN TECHNOLOGIES GMBH

Dates

Publication Date
20260505
Application Date
20180305
Priority Date
20170324

Claims (20)

  1. 23 Claims 1. A reaction device { 1) comprising a first wall (2), which defines an interior (3), the interior configured to accommodate a stirring mechanism (4), wherein a heat exchanger { 5) is at least partly provided on a surface of the first wall (2) that faces away from the interior (3) and/or on the stirring mechanism (4), the heat exchanger (5) including at least two layers each of which has a grate structure.
  2. 2. The reaction device according to claim 1, characterized in that it has a double wall comprising the first wall (2) and a second wall (6), so that an intermediate space (7), which accommodates the heat exchanger (5), is formed between the first wall (2) and the second wall (6).
  3. 3. The reaction device according to claim 2, characterized in that the reaction device is a tube furnace { 1 a).
  4. 4. The reaction device according to any one of claims 1 to 3, characterized in that the stirring mechanism (4) is a screw conveyor (18).
  5. 5. The reaction device according to claim 4, characterized in that the screw conveyor (18) comprises screw sections {25a, 25b, 25c), which have different pitches.
  6. 6. The reaction device according to any one of claims 1 to 5, characterized in that the reaction device has at least two reaction zones { 13a, 13b, 13c, 13d) with different temperatures. Date Re1rue/Date Received 2024-02-16 24
  7. 7. The reaction device according to any one of claims 1 to 6, characterized in that the layers of the heat exchanger (5) are connected to one another at their contact points (8) or contact surfaces.
  8. 8. The reaction device according to any one of claims 1 or 7, characterized in that the structure of a grate comprises or consists of a mesh screen.
  9. 9. The reaction device according to claim 8, characterized in that the mesh screen has a mesh size of 3 mm to 30 mm.
  10. 10. The reaction device according to claim 8 or 9, characterized in that a gap volume fraction of the mesh screen is 90 % to 95 %.
  11. 11. The reaction device according to any one of claims 8 to 10, characterized in that a surface density of the mesh screen for convective heat transfer from gas to grate is between 200 m2/m3 and 500 m2/m3.
  12. 12. The reaction device according to any one of claims 8 to 11, characterized in that a channel width of the mesh screen is between 30 mm and 150 mm.
  13. 13. The reaction device according to any one of claims 1 to 12, characterized in that the heat exchanger (5) comprises or consists of a metal, a metal alloy, a sintered metal compound or a ceramic material.
  14. 14. The reaction device according to any one of claims 1 to 13, characterized in that the heat exchanger (5) includes a catalyst. Date Re1rue/Date Received 2024-02-16
  15. 15. The reaction device according to any one of claims 1 to 14, characterized in that the heat exchanger (5) is designed as a reflector.
  16. 16. The reaction device according to any one of claims 1 to 15, characterized in that the heat exchanger (5) has fins (10).
  17. 17. The reaction device according to any one of claims 1 to 16, characterized in that the heat exchanger (5) is present together with the insulation material { 16).
  18. 18. Use of the reaction device according to any one of claims 1 to 17 for carbonizing, cracking and reforming biomass and/or bioresidues.
  19. 19. Use of the reaction device according to any one of claims 1 to 17 for removing heat from exothermic processes and for heat recovery.
  20. 20. Use of the reaction device according to any one of claims 1 to 17 for the dynamic control of temperature-controlled reactor systems in which heat is first supplied to the process taking place in the reactor and the heat is dissipated after exceeding a predetermined threshold. Date Re1rue/Date Received 2024-02-16

Description

REACTION DEVICE WITH HEAT EXCHANGER AND USE THEREOF FIELD The invention relates to a reaction device with an outer wall that defines an interior which accommodates a stirring mechanism, the reaction device further comprising a heat exchanger with a grate structure. It is thus possible to transfer heat in a precise and efficient manner primarily by means of thermal radiation in endothermic processes at different temperature levels, in particular pyrolysis, gasification and reforming, and thereby use the exhaust heat from other processes. BACKGROUND In both the thermal and thermo-chemical conversion of biomass and similar organic feedstocks, heat is transferred via heat exchangers into the material to be processed. Examples of use are pyrolysis, gasification and reforming reactors for the decomposition and conversion of biomass or plastics. In these processes, it is technically difficult to transfer a large amount of heat into the material to be processed, in part as quickly and, at the same time, efficiently as possible. For ecological and economic reasons, it is here advantageous to use exhaust heat from the combustion of individual conversion products. This exhaust heat is potentially often sufficient to provide the required amount of heat. However, especially in the case of cylindrical reactors, it is not possible to transfer a sufficiently large amount of heat from waste gases into the material to be processed from the outside. The reasons are the relatively small heatexchanging surface area and the generally low heat capacity of gases. Although the heat-exchanging surface area can be increased by special heat exchanger designs, such as finned bodies, these modifications are always 2 associated with high pressure losses. For this reason, a cascade series connection of several heat exchangers is often impossible. With regard to the heating medium, water as a heat transfer medium would be an alternative with a higher heat capacity, but the use of water at temperatures above 100°C with the same volume is accompanied by a strong increase in pressure. This severely restricts or at least complicates a use as a heat transfer medium and thus also affects safety aspects of the entire system. Liquid heat transfer media on the basis of salt, on the other hand, have a much higher boiling point, but the melting point is also often significantly above 0°C, so that they could solidify in the heat exchanger when the system is at a standstill. If one accepts the additional technical equipment and safety expenditure when using pressurized heat transfer media, pressurized hot gases are also suitable in addition to steam. The advantage here is significantly lower pressure losses compared to the use of liquid and vaporous heat transfer media. In order to allow the heat input into the pyrolysis and gasification reactors, different ways or combinations thereof have been used so far: indirect heating from the outside, in particular electrically or on the basis of burners, indirect heating from the inside, in particular through the screw shaft or hollow screw surfaces; e.g. hollow screw heat exchangers (inter alia DE 4412536, US2335422, US3909958, US4930484, DE3503069), direct contact of the heating medium with the material to be converted through inflow of a heated (inert) gas (e.g. DE 60104724), 3 direct contact of the heating medium with the material to be converted through heated heat exchange particles, such as balls, which are added to the material to be processed {inter alia DE2345800, DE37 6791, DE508566, DE60104724, DE102009007176, US2877106, US4110193). These and other concepts are partially modified or slightly adapted for the efficient heat transfer by means of thermal radiation. Examples are inter alia black anodized finned bodies or paintwork with paint that emits large amounts of radiation in the infrared range. Patent specification GB19310012139 from 1931 describes a heat exchanger that uses a reticular structure. The fabric mentioned in this document is a twodimensional fabric which is transformed into a three-dimensional body by bending and folding. SUMMARY Proceeding from the prior art, the object of the invention is therefore to provide a reaction device with a heat exchanger with improved properties. The invention proposes a reaction device with a first wall which defines an interior that accommodates a stirring mechanism, a heat exchanger being at least partly provided on the surface of the first wall that faces away from the interior and/or on the stirring mechanism, wherein the heat exchanger has a grate structure and at least two layers are provided which have a grate structure. Date Re1rue/Date Received 2024-02-16 4 A reaction device in the sense of the present invention is understood to mean any device in which a reaction can be carried out. Examples of such reaction devices are reactors, in particular in the form of a cylinder, for example tube furnaces. The term reaction device may refer to a reactor