Burner for the combustion of material for combustion in the form of a comminuted wood product, in particular of fine material

{
  "publication_number": "US11149944B2",
  "country": "US",
  "kind": "B2",
  "title": "Burner for the combustion of material for combustion in the form of a comminuted wood product, in particular of fine material",
  "abstract": "The disclosure relates to a burner for burning combustible material in the form of a comminuted wood product, especially fine material, with (a) a combustible material feed for supplying the combustible material, (b) a screw conveyor for conveying the combustible material, (c) a combustion zone, wherein the screw conveyor is arranged to convey the combustible material (18) from the combustible material feed (20) to the combustion zone, (d) an air feed for supplying air to the combustion zone, and (e) a burner mouth for leading combustion gases out of the combustion zone. According to the disclosure, a compacting zone is provided, which is configured behind the combustible material feed and in front of the combustion zone in the direction of material flow (M) of the combustible material, wherein an auger of the screw conveyor and the compacting zone are preferably designed to compress the combustible material in the compacting zone.",
  "claims": [
    "1. A burner for burning combustible material in the form of a comminuted wood product comprising: (a) a combustible material feed which feeds the combustible material, (b) a screw conveyor which conveys the combustible material, (c) a combustion zone, wherein the screw conveyor is arranged to convey the combustible material from the combustible material feed to the combustion zone, (d) an air feed which feeds air into the combustion zone, (e) a burner mouth which discharges combustion gases out of the combustion zone, (f) a compacting zone that is arranged behind the combustible material feed and in front of the combustion zone in a direction of material flow of the combustible material, and (g) an auger of the screw conveyor and the compacting zone to compress the combustible material in the compacting zone, wherein the screw conveyor includes an electric drive, which is configured to automatically keep a torque acting on the auger at a constant.",
    "2. The burner according to claim 1, further comprising a gasification zone which gasifies the combustible material, the gasification zone being arranged behind the compacting zone in a direction of material flow.",
    "3. The burner according to claim 1, wherein the compacting zone includes a tapering cross-section in the direction of material flow.",
    "4. The burner according to claim 1, wherein the auger has a decreasing pitch in the compacting zone.",
    "5. The burner according to claim 1, wherein the electric drive comprises: an electric motor; and a control unit, which features a frequency converter and is configured to automatically keep the torque acting on the auger at the constant.",
    "6. The burner according to claim 5, wherein the combustible material feed has a filling monitoring device, wherein the control unit is designed to control the electric motor in such a way that the screw conveyor is always filled with the combustible material.",
    "7. A steam boiler system comprising: (a) a steam boiler, (b) a wall which encloses a firing chamber, (c) a burner according to claim 1, whose combustible material feed is arranged outside of the firing chamber, and (d) wherein the burner protrudes into the firing chamber by way of its compacting zone.",
    "8. A wood material panel production system comprising a wood comminution system that produces a comminuted wood product during operation, a classification device for separating fine material from the comminuted wood material such that coarse material remains, the steam boiler system according to claim 7, wherein the burner is connected to the classification device which feeds of the fine material and a firing grate is connected to the classification device which feeds coarse material.",
    "9. A method for burning fine material for which a burner according to claim 1 comprising: compressing of the combustible material in the compacting zone by the screw conveyor, evaporation of water held in the combustible material, gasification of the combustible material, thereby producing a wood gas, and burning of the wood gas in the air that is supplied by the air feed.",
    "10. The method according to claim 9, further comprising a temperature (T 34) in a firing chamber of the burner being at least 850° C.",
    "11. A steam boiler system comprising: (a) a steam boiler, (b) a wall which encloses a firing chamber, (c) a burner for burning combustible material in the form of a comminuted wood product, comprising: (i) a combustible material feed for feeding the combustible material, (ii) a screw conveyor for conveying the combustible material, (iii) a combustion zone, wherein the screw conveyor is arranged to convey the combustible material from the combustible material feed to the combustion zone, (iv) an air feed for feeding air into the combustion zone, (v) a burner mouth for discharging combustion gases out of the combustion zone, and (d) the burner having a compacting zone that is arranged behind the combustible material feed and in front of the combustion zone in a direction of material flow of the combustible material, (e) wherein the combustible material feed is arranged outside the firing chamber and that (f) the burner protrudes into the firing chamber with its compacting zone.",
    "12. A method for burning fine material using the steam boiler system according to claim 11, wherein: fine material is fed by means of the combustible material feed and is then fed from the combustible material feed to the combustion zone by means of the screw conveyor, and air is fed to the combustion zone and combustion gases are discharged from the combustion zone through the burner mouth."
  ],
  "description_excerpt": "The invention relates to a burner for burning combustible material in the form of a comminuted material product, especially fine material, according to the generic term in claim 1. Fine material refers to wood particles that have a small diameter, for instance a maximum of 3 mm, wherein the length of the particles of the fine material is generally shorter than 40 mm. This type of fine material is generated in sawmills, for example, and during the production of wood material panels. Since process heat is also required during the production of wood material panels, residual materials, and thus also the fine material, are generally burned.\n\nHere, the burning of fine material is problematic. Due to the small size of the particles, the fine material in the furnace is easily entrained by the air stream and therefore leaves the firing chamber very quickly. The time in the firing chamber is generally not long enough to ignite the fine material, as it often has a high water content. As a result, a large proportion of the combustion occurs behind the firing chamber and especially in the flue gas cleaning system arranged downstream from said firing chamber. On the one hand, this means that any heat generated during the burning process cannot be used to generate steam; on the other hand, it renders the cleaning of flue gas more difficult.\n\nFR 2 727 744 A1 describes a fine material burner, with which the fine material that is to be burned is transported to a combustion zone via a screw and then mixed with combustion air in said combustion zone. The disadvantage of such a system is the risk of ash adhesions.",
  "cpc": [
    "F23G 7/105",
    "B65G 33/34",
    "F23B 40/00",
    "F23D 1/04",
    "F23D 2201/10",
    "F23G 2202/103",
    "F23G 2203/8013",
    "F23G 2205/121",
    "F23G 2206/203",
    "F23G 2209/261",
    "F23G 2900/50209",
    "F23G 5/16",
    "F23G 5/46",
    "F23G 7/10",
    "Y02E 20/12"
  ],
  "ipc": [
    "F23G 5/16",
    "F23G 5/46",
    "F23G 7/10"
  ],
  "assignees": [
    "Swiss Krono Tec AG"
  ],
  "inventors": [
    "Hartmut LEMKE"
  ],
  "filing_date": "2018-05-28",
  "publication_date": "2021-10-19",
  "grant_date": "2021-10-19",
  "priority_date": "2017-05-29",
  "application_number": "US-201816614222-A",
  "family_id": "58779028",
  "cited_by_count": 0,
  "citations": [
    "US3865053A",
    "US3935824A",
    "RU2129687C1",
    "FR2727744A1",
    "EP0906542A1",
    "US6276286B1",
    "US20040134397A1",
    "EP1331443A1",
    "US20070289509A1",
    "DE102007017101A1",
    "JP2010096446A",
    "RU104668U1",
    "EP2657598A2",
    "US20140155245A1",
    "US20140069798A1",
    "US20140175335A1",
    "US20150362184A1",
    "US20170145314A1",
    "US20170336070A1",
    "US20180022554A1"
  ]
}