[0014] The device shown in Figure 1 is used to purify a medium, where this medium is gas discharged or exchanged from a coal mine. Such exhaust gas usually contains flammable substances, that is, flammable methane gas. When the inventive device indicated by the reference number 7 as a whole is not in use, the exhaust gas in the mine 1 is sent to the flue 4 through the fan 2 and the valve 3, or sent to the flue 6 through the fan 5.
[0015] According to the illustrated embodiment, the device 7 proposed by the present invention includes four combustion exchangers, which are generally labeled 8, 8 I ,8 II ,8 III ,8 IV It means that, of course, it can also include more or fewer combustion exchangers depending on the application area. Each combustion exchanger 8 is connected to a plurality of inlet pipes 11 and a plurality of outlet pipes 12 through a process fan 9 common to all combustion exchangers, and a valve 10 provided for each combustion exchanger. According to the illustrated embodiment, there are 9 inlet pipes and 9 outlet pipes, but the number of inlet and outlet pipes can be different from this. Each inlet pipe 11 and each outlet pipe 12 are equipped with a braking device, and they are generally indicated by the numbers 13 and 14 respectively. The outlet pipe 12 leads to the flue 6 through a valve 15 equipped with each combustion exchanger 8. For example, four fans can be used instead of a single fan 9. In this case, each combustion exchanger is equipped with one fan.
[0016] FIG. 2 is a schematic cross-sectional view through the combustion exchanger 8. The braking devices 13 and 14 are separately equipped with gates 18 and 19, which can move vertically between the two sealing positions. When in the sealing position, each gate sealingly abuts on its channels 16 and 17 respectively. The two gates 18 and 19 never seal the same passage. In the position shown by the solid line, the gate 18 seals the entrance 20 leading to the passage 17, and the gate 19 seals the exit 21 from the passage 16. Therefore, the valence containing flammable substances enters the bed 23 of the combustion exchanger through the inlet pipe 11 through the inlet 22 of the channel 16, where the flammable substances are combusted in the originally known manner, and the air flow continues outward through the channel 17 Its outlet 24 flows to the outlet pipe 12. In FIG. 2, this flow is schematically represented by a solid arrow 25. The flow direction of the bed 23 through the combustion exchanger is reversed from time to time in a previously known manner to avoid that the heat front of the bed 23 is too close to one of the channels 16, 17. During such a reversal, the shutters 18 and 19 move to the positions shown by the dashed lines in FIG. 2, and the flow corresponding to the positions of these shutters is schematically indicated by the dashed arrows 26.
[0017] Obviously, the valves 10, 15 can be used to stop air flow to and out of a combustion exchanger during maintenance, for example, for maintenance or the like. It can be further seen that the valve 3 is a valve that opens or closes the flow to the flue 4 according to the flow through the fan 9, so as to ensure that the mine 1 is always ventilated regardless of whether the flow passes through the device 7.
[0018] In the central area of the bed 23, called the combustion zone, there is a heating device 27, which can be electrically heated. With this heating device 27, for example, when the combustion exchanger is started, the bed can be heated to the spontaneous combustion of combustible substances. temperature.
[0019] In the combustion zone there is also a draft tube or diverter device 28, which is used to diverge part of the flow of the heated medium after combustion. According to this embodiment, the flow dividing device 28 is a perforated pipe extending along the bed 23 of the combustion zone, but it can also be made into other shapes, for example, a device that sucks the medium directly through the wall 29 of the bed 23. According to the illustrated embodiment, the flow dividing device 28 is in turn connected to the steam boiler 30 shown schematically in FIG. 1. The medium divided by the dividing device 28 is conveyed to the flue 6 through the steam boiler 30 via the fan 31, and the fan 31 is used to compensate the pressure drop in the boiler.
[0020] According to the illustrated embodiment, the auto-ignition temperature in the combustion exchanger is about 1000°C. According to this, the combustible material is preferably composed of methane gas discharged from the coal mine, and the medium directly diverted from the combustion zone can be in the steam boiler 30 Use it effectively to generate electricity through the application of steam turbines and generators. This electric energy can be used to operate one or several fans 2, 5, 9 and 31 according to the above embodiment. Considering the risk of explosion, during mining, the tunnel must always be ventilated. At least one of the fans 2 and 5 must operate permanently, even when the electrical bus fails. Otherwise, the mine must be emptied, which is a difficult, time-consuming and expensive operation. Thanks to the invention, such fans can be operated in an economical and effective manner, and the mine does not need to rely on the power supply of the external power distribution network. In addition, the excess electricity generated by steam boilers, turbines and generators can be sold. In this way, the invented device and method rely on the combustion in the bed 23 to generate electricity at the same time, making it economically effective and technically possible to protect the environment.
[0021] In coal mines, the methane gas concentration of exhaust gas usually reaches up to 20% L.E.L. (low explosion limit). It has proved possible to build such a combustion exchanger with a thermal efficiency of 98%. This means that when the methane concentration in the medium exceeds 0.1% (2% L.E.L), the combustion exchanger can self-sufficiently maintain the auto-ignition temperature in the combustion zone. This also shows that the application of the present invention makes it possible to recover electric energy from a medium containing a low concentration of flammable substances, which has been practically impossible so far. In addition, the amount of medium diverted by the diverter device 28 can be used to control the temperature in the bed 23 to prevent the combustion zone from becoming too wide and contacting the shell surrounding the bed, which itself contains the risk of fire, as well as Unnecessary energy loss. With the device of the present invention, the split flow can also be easily controlled by changing the split flow, so as to offset any change in the mass of combustibles in the medium flowing through the bed 23. The combustion process is also very clean, because no instantaneous and/or hot NO is produced in the flame during combustion X.
[0022] It is clear that certain modifications can be made to the illustrated embodiment. For example, the number of combustion exchangers 8 and the number of splitters 28 in each bed 23 can be changed. Obviously, the structure and details of the braking devices 13 and 14 can also be different from those shown, as long as they can change the direction of flow in the bed 23. In addition, the shapes of the channels 16, 17 can also be different, for example can be composed of hollow tubes arranged in the bed 23, and the combustion zone is established between them, for example as described in the Swedish patent specification 9103634-3. It is also clear that any regenerative burner can be used in place of the combustion exchanger.
[0023] Of course, the heating medium can also be used to generate other forms of energy other than electric energy. In this case, the split device 28 can also be connected to other types of energy generation devices other than the steam boiler 30. For example, the heated medium can be used to heat another medium, such as water, in which case the thermal energy in the second medium can be used instead, for example, in a district heating system. In addition, in this case, the heat energy in the heated medium can be recovered by means of a diversion device, which is in the form of at least a pipe, which allows the corresponding flow of the second medium to pass through, and it is placed in The combustion zone of the regenerative burner is preferably in the bed 23 of the combustion exchanger.
[0024]The device and method proposed by the present invention are not limited to the application in mining operations, but can also be applied to the following ventilation devices in various processes and occasions, such as paint production process, printing workshop, spraying and lamination process, chemical and pharmaceutical Product production, animal breeding equipment, bacterial decomposition factories, waste siltation, and plastic and tire production; in other words, it can be applied to such factories and processes in which certain hydrocarbons such as solvents, styrene, plastic fumes are present in the medium Compounds, gas discharged from fuel tanks, gas discharged from fish processing industry, diesel engine or natural gas soot, or flammable inorganic substances such as carbon monoxide discharged from electric furnace steelmaking production, or hydrogen discharged from chemical industry, such The medium needs to be transported through a regenerative burner, preferably a combustion exchanger. All kinds of flammable substances, that is to say, also include the malodor or toxic substances emitted from various processes, or from degassing or gas leakage, which can be effectively eliminated from the medium, and at the same time, energy is generated. It is also easy to understand that the present invention does not necessarily have to be used in conjunction with flue 4, 6, fan 2, 5 or valve 3 as shown in Fig. 1, but can be applied to any equipment as long as the medium in it meets the above requirements.
[0025] Various changes and modifications included in the basic idea of the invention can be made as long as they fall within the protection scope of the appended claims.
