JP2005195281A - Burning melting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a burning melting device, restraining degradation of slug. <P>SOLUTION: This burning melting device includes: a vertical burning melting furnace 1 for burning thermal decomposition gas generated by thermal decomposition of waste; a slug recovery port 3 provided on the bottom of the burning melting furnace 1 to recover molten slug 29; a first gas duct 19 connected to the bottom 17 of the burning melting furnace to be raised; a second gas duct 21 connected to the first gas duct 19 to be extended substantially horizontally or downward from the level; and an air heater 5 formed by disposing a heat transfer pipe for circulating the air to the second gas duct 21, whereby degradation of slug is overcome. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a combustion melting apparatus including an air heater that heats air using combustion exhaust gas from a combustion melting furnace.

  As a method of treating waste, the waste is led to a pyrolysis reactor for pyrolysis, and the pyrolysis gas and pyrolysis residue generated by this pyrolysis are introduced into a combustion melting furnace for combustion treatment, This combustion heat melts incombustible particles (hereinafter referred to as fly ash) contained in pyrolysis gas and pyrolysis residue, recovers molten slag, and uses it for aggregates of building materials and paving materials. Things have been done.

  On the other hand, an air heater consisting of a plurality of heat transfer tubes is installed in the flue on the downstream side of the combustion melting furnace to exchange heat between the high-temperature combustion exhaust gas discharged from the combustion melting furnace and the air flowing through the heat transfer tubes. The heat of combustion exhaust gas is recovered and air heated thereby is used as a heat source (see Patent Document 1).

  This type of combustion melting apparatus is provided with a slag recovery port for recovering molten slag at the bottom of the combustion melting furnace, and the air heater is installed in a flue formed by raising from the bottom of the combustion melting furnace. By recovering the heat of the high-temperature combustion exhaust gas (for example, 1100 ° C) flowing in the road and supplying heated air to the pyrolysis reactor, the waste is pyrolyzed (for example, 450 ° C). . In addition, the combustion exhaust gas (for example, 600 degreeC) heat-recovered with the air heater is guide | induced to a boiler etc., and is further heat-recovered.

JP 2000-130722 A

  By the way, most of the fly ash discharged from the combustion melting furnace is melted and turned into slag, but a part of the fly ash flows in the flue without being melted, for example, adheres to the heat transfer tube surface of the air heater. Is done. Therefore, according to the above configuration, when a predetermined amount of fly ash adhering to the surface of the heat transfer tube is accumulated, the fly ash may fall in the flue due to the gravity and be mixed into the molten slag.

  That is, molten slag is usually cooled by flowing down from the slag collection port into the water tank to obtain a homogeneous property. However, when solidified fly ash is mixed in the molten slag, the slag after cooling is uneven. This may cause problems in reuse.

  An object of the present invention is to suppress deterioration in the quality of slag.

  In order to solve the above-described problems, the present invention recovers a molten slag provided at the bottom of a vertical combustion melting furnace that combusts a pyrolysis gas generated by pyrolyzing waste and the combustion melting furnace. A slag recovery port, a first flue that is set up and communicated with the bottom of the combustion melting furnace, and communicates with the first flue and extends either substantially horizontally or downward from the horizontal. And a second air flue provided with a heat transfer pipe through which air is passed through the second flue.

  According to this, since fly ash adhering to the air heater does not fall into the first flue and mix into the molten slag, it is possible to suppress deterioration in the quality of the slag discharged from the slag recovery port. it can. In addition, the fly ash adhering to the air heater can be collected separately from the slag, for example, by providing the fly ash collection means at the bottom of the second flue.

  According to the present invention, it is possible to suppress deterioration in slag quality.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment of a combustion melting apparatus of the present invention. As shown in the figure, the combustion melting apparatus of this embodiment includes a combustion melting furnace 1, a slag recovery port 3, air heaters 5 and 7, and a fly ash discharge port 9.

  The combustion melting furnace 1 is formed in a vertical cylindrical shape, and a burner 11, a pyrolytic carbon blowing section 13, and a pyrolytic gas blowing section 15 are arranged on the top thereof. A furnace bottom 17 extending in a substantially horizontal direction is connected to the bottom of the combustion melting furnace 1, and a slag recovery port 3 is provided in the furnace bottom 17. Connected to the furnace bottom portion 17 is a flue 19 formed vertically up to a height near the top of the combustion melting furnace 1. Further, the flue 19 is connected with a flue 21 formed by being bent in a substantially horizontal direction and then vertically falling. As shown in the figure, the flue 21 is formed by being partitioned from the flue 25 by the partition plate 23, and the flue gas flowing downward through the flue 21 flows into the flue 25 through the bottom and again upwards. It comes to flow. A flue 27 extending in the horizontal direction is connected to the flue 25 at the top.

  Air heaters 5 and 7 are disposed inside the flues 21 and 25, respectively. These air heaters are made of, for example, ceramic heat transfer tubes made of a single tube through which air flows, and a plurality of heat transfer tubes are arranged orthogonal to the flow direction of the combustion exhaust gas. The heat transfer tubes communicate with each other outside the furnace wall, and the air introduced from the outside of the furnace wall flows through each heat transfer tube, exchanges heat into heated air, and is discharged outside the furnace. Further, a fly ash discharge port 9 is provided at the bottom where the flues 21 and 25 communicate with each other, and fly ash falling from the heat transfer tube surfaces of the air heaters 5 and 7 is collected.

  In the present embodiment, the air heaters 5 and 7 are divided into two flues. However, the present invention is not limited to this. For example, the length and width of one flue are enlarged, and the flue is The number of installed heat transfer tubes may be increased.

  Next, the operation of this embodiment will be described. When a fuel such as pyrolytic carbon is introduced into the combustion melting furnace 1 in a high temperature state together with the pyrolysis gas, it burns and the furnace bottom 17 becomes a high temperature of about 1300 ° C. Fly ash generated by these combustion is melted at the furnace bottom 17 while swirling in the furnace, and molten slag 29 is generated. The molten slag 29 generated here flows down along the furnace wall, falls from the slag recovery port 3 into a water tank outside the furnace, and is cooled and solidified.

  On the other hand, high-temperature combustion exhaust gas (for example, 1100 ° C.) containing a part of the fly ash that is not melted is guided to the flue 21 via the furnace bottom 17 and the flue 19, and the heat transfer tube surface of the air heater 5 is passed through the surface. It is cooled by heat exchange. Further, the combustion exhaust gas that has passed through the air heater 5 is guided to the flue 25, and is cooled (for example, 600 ° C.) by the air heater 7 in the same manner as the air heater 5, and is passed through the flue 27 to a waste heat boiler or the like. Supplied.

  Here, when the combustion exhaust gas passes through the flues 21 and 25, the fly ash accompanying the combustion exhaust gas adheres to the surfaces of the heat transfer tubes 5 and 7 and gradually accumulates. According to the present embodiment, when fly ash falls from the heat transfer tube surface by gravity, it is discharged to the outside through the fly ash discharge port 9, so that mixing into the molten slag 29 can be prevented. In other words, the air heater 5 is provided in a flue 21 formed vertically by sandwiching the flue 19 and is installed at a position cut off from the slag collection port 3. Fly ash can be collected separately.

  In addition, although it is preferable to form the flue 21 falling vertically, it is not limited to this, For example, you may make it extend substantially horizontal or downward from horizontal.

  Next, a waste disposal apparatus provided with the combustion melting apparatus of the present invention will be described. FIG. 2 is a system diagram showing an embodiment of the waste treatment apparatus. The waste is crushed to a predetermined size, introduced into a rotary drum type pyrolysis reactor 33 by a screw feeder 31, heated to, for example, about 450 ° C., and pyrolyzed in a low oxygen atmosphere.

  The pyrolysis gas and pyrolysis residue generated from the pyrolysis reactor 33 are guided to the discharge device 35, and the pyrolysis gas is supplied to the combustion melting furnace 1 together with combustion air through the pipe 37, while the pyrolysis residue is Then, after being guided to the cooling device 39 and cooled to about 80 ° C., for example, it is introduced into the sorting device 41.

  The separation device 41 is, for example, a known method such as a fluid type, a sieve, a magnetic separation type, an eddy current type, a centrifugal type, etc. Sorted into non-metallic components. Here, the combustible granular material includes a relatively large combustible material in addition to the pyrolytic carbon granular material, and these are stored in the hopper 43 after the pulverization process. Other separated components are appropriately discharged into a container or a hopper, and the granular material in the hopper 43 is introduced into the combustion melting furnace 1 through the pipe 45.

  The pyrolytic carbon and the pulverized product introduced into the combustion melting furnace 1 form a swirl flow in a high temperature atmosphere to form molten slag, and fall from the slag recovery port 3 to the water tank 47. Here, the combustion exhaust gas is heat-recovered by the air heater installed in the downstream side flue of the combustion melting furnace 1 as described above, and the heated air is used as a heat source for heating of the pyrolysis reactor 33. Is done. The heated air is not limited to the heat source of the pyrolysis reactor 33, and may be used as another heat source.

  The combustion exhaust gas heat-recovered by the air heater is cooled to, for example, 600 ° C., and is efficiently recovered by the waste heat boiler 49 on the downstream side. Here, the waste heat boiler 49 generates steam using heat recovered from the combustion exhaust gas, and rotates the steam turbine generator 51 to recover electric power.

  The combustion exhaust gas discharged from the waste heat boiler 49 is guided to the dust collector 53 for dust removal, and then purified by a gas purification device such as the desalination device 55, and then from the chimney 59 to the atmosphere via the induction blower 57. Released.

  As described above, according to the present embodiment, it is possible to suppress the deterioration of the slag quality caused by the fall of the fly ash adhering to the air heaters 5 and 7, and to improve the slag utilization efficiency.

The longitudinal cross-sectional view which shows one Embodiment of the combustion melting apparatus of this invention is shown. It is a systematic diagram which shows one Embodiment of the waste treatment plant containing the combustion melting apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combustion melting furnace 3 Slag collection | recovery port 5,7 Air heater 9 Fly ash discharge port 17 Furnace bottom part 19,21,25,27 Flue 23 Partition plate 29 Molten slag

Claims (1)

A vertical combustion melting furnace that combusts pyrolytic gas generated by pyrolyzing waste, a slag recovery port that is provided at the bottom of the combustion melting furnace and collects molten slag, and a bottom of the combustion melting furnace A first flue that is provided in communication with the first flue, and a second flue that is provided in communication with the first flue and extends substantially horizontally or downward from the horizontal. A combustion melting apparatus comprising: an air heater provided with a heat transfer tube through which air is passed through the second flue.

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