JP5574475B2 - Waste melting treatment method and waste melting treatment apparatus - Google Patents

Description

  The present invention relates to a waste melting process for melting a thermal decomposition residue obtained by drying and pyrolyzing waste to remove moisture and volatile components in the waste.

  A waste material such as general waste and industrial waste is melted in a shaft furnace type waste melting furnace. As shown in FIG. 2, the waste material is charged into the melting furnace 31 together with auxiliary materials such as coke and limestone by a charging device 32 from the top of the furnace. The waste is discharged as a melt from the tap 33 through processes of drying, pyrolysis, combustion, and melting in the furnace. Some of the combustibles in the waste are thermally decomposed and discharged as gas, and some are combusted by air and oxygen blown from the tuyere 34 at the bottom of the furnace, while the remaining combustibles are combustible. Dust is discharged from the top of the melting furnace 31 as dust.

  The combustible dust discharged from the top of the melting furnace 31 is collected by the combustible dust collecting device 35, stored in the combustible dust storage tank 36, cut out by the combustible dust cutting device 37, and enriched with oxygen. It is blown into the furnace from the tuyere 34 for supplying the crystallization air. The exhaust gas that has passed through the combustible dust collecting device 35 is burned in the subsequent combustion chamber.

  In the waste melting treatment by the melting furnace 31, the ratio of the coke used as the main fuel for melting the processed material to the processing cost is large, so that the amount of coke used can be reduced in order to save the processing cost. It is desired.

On the other hand, from the viewpoint of preventing global warming, coke derived from fossil fuels is used as a melting heat source, so that reduction of coke usage is also desired in order to reduce the CO ₂ load on the environment.

  In order to reduce the amount of coke used, for example, a method of injecting combustible materials other than combustible dust together with combustible dust discharged from the top of the furnace through the tuyere (Patent Document 1), oxygen supplied from the lower blowing tuyere The ratio (B / A) of the theoretical oxygen amount (B) obtained from the amount and composition of the combustible dust and coke collected and supplied from the lower air tuyeres to the amount (A) is 0.5 to 1. Enrichment of air or oxygen blown from the tuyere of coke filled in the furnace by a heating coil (Patent Document 2) A waste-melting method (Patent Document 3) in which waste is melted by reducing and burning with air and inductively heating the coke with an alternating current, or biomass such as wood And a method of use (Patent Document 4) have been proposed.

JP 2006-207911 A JP 2003-056820 A JP 2002-054810 A JP 2007-93069 A

  In the packed bed in the shaft furnace type gasification melting furnace, the temperature of the solid is raised by direct heat exchange, so the heat efficiency is good, but in the waste, high-moisture waste such as garbage and volatilization of wood etc. There are some which have many parts and large diameters. For this reason, in the conventional shaft type gasification melting furnace, a part of these wastes are not sufficiently dried, and the gasification of the volatile matter is sufficiently performed to descend to the bottom of the furnace, It was burned and melted with coke. Since moisture and volatile matter in the lower part of the furnace both lower the atmospheric temperature, it is necessary to increase the amount of coke used as a result in order to maintain the atmospheric temperature high and completely dissolve non-combustibles. Further, when using external fuel such as LPG as a substitute for coke, the amount of external fuel (coke + gas) used remains high. Also, in the conventional shaft furnace type gasification melting furnace, gasification of volatile matter in the packed bed is performed when charging waste or when undried / undried waste falls to the bottom of the furnace. There was a change in the amount of steam and exhaust gas.

  Furthermore, in the conventional shaft furnace type gasification and melting furnace, moisture and volatile components are not uniformly dried and gasified, and a gas drift phenomenon called blow-through may occur.

  Therefore, the present invention can reduce the amount of external fuel used by making the flow of gas generated in the grate part and pyrolysis residue melting part uniform in the waste packing layer formed in the drying shaft part. A waste melting method and apparatus are provided.

The waste melting treatment method of the present invention generates a pyrolysis residue in a waste filling layer formed by charging waste into the drying shaft portion from the top of the drying shaft portion for drying and pyrolyzing the waste. Passes through the gas generated in the pyrolysis residue melting section that melts the pyrolysis residue using a coke bed formed by adding coke and limestone from the auxiliary material inlet at the top of the pyrolysis residue melting section and the pyrolysis residue melting section In addition to drying and pyrolyzing the waste, the gas that has passed through the waste packed bed is discharged from the top of the drying shaft, and the waste dried by the drying shaft is pyrolyzed by the grate and heated. A decomposition residue is generated, and the generated pyrolysis residue is continuously supplied from the grate part to the pyrolysis residue melting part and melted, and a gas flow in the dry shaft part is detected to detect an air flow from the grate part, Air temperature, air balun And / or changing the grate speed, characterized in that a uniform gas flow in the drying shaft portion.

Further, the waste melting treatment apparatus of the present invention is provided with a waste charging inlet and an exhaust gas exhaust outlet at the top, and a grate portion and a waste filling layer formed by charging waste from the waste charging inlet and The gas generated in the pyrolysis residue melting part is allowed to dry and pyrolyze the waste, and the gas passing through the waste packed bed is discharged from the exhaust gas exhaust port, and the drying shaft part Connected to the lower part, connected to the grate part that pyrolyzes the waste dried by the drying shaft part to produce a pyrolysis residue, and to the outlet side of the pyrolysis residue of the grate part, and is supplied from the grate part The pyrolysis residue melting section is sequentially arranged with a coke bed formed by adding coke and limestone from the auxiliary material inlet at the top of the pyrolysis residue melting section, and the pyrolysis residue melting section is dried. Gas flow to the shaft Control means for making the gas flow in the drying shaft portion uniform by changing the amount of air blown from the grate portion, the air blowing temperature, the air flow balance and / or the grate speed according to the detection signal. It is characterized by having.

  The present invention detects the gas flow in the drying shaft portion and changes the factors such as the air volume of the grate portion, the air temperature, the air balance, and the grate speed to make the gas flow uniform. It is possible to exchange heat appropriately between the furnace gas and the waste in the section, and to reduce the amount of external fuel used such as coke.

It is the schematic which shows the waste fusion processing apparatus provided with the grate used in this invention. It is explanatory drawing of the conventional waste fusion processing equipment.

  The present invention will be described with reference to the drawings.

  In FIG. 1, the waste melting apparatus of the present invention is a drying shaft portion 1 for drying and pyrolyzing the charged waste, and further decomposing the waste dried and pyrolyzed by the drying shaft portion 1. And a pyrolysis residue melting section 3 that burns and melts the pyrolysis residue generated in the grate section 2. The drying shaft portion 1 is disposed above the entrance side of the grate portion 2, and the pyrolysis residue melting portion 3 is disposed below the exit side of the grate portion 2, communicated with the crank shape and integrally connected. Yes.

  A waste charging inlet 4 and an exhaust gas outlet 5 are provided at the top of the drying shaft portion 1. A waste filling layer 6 is formed by the waste charged from the waste charging inlet 4 in the drying shaft portion 1. The gas generated in the grate part 2 and the pyrolysis residue melting part 3 passes through the waste packed bed 6, and the passed gas is discharged from the exhaust gas outlet 5 at the top.

  The drying shaft portion 1 has a gas flow detection means 7 such as a thermometer or thermography for detecting the gas temperature or waste temperature in the drying shaft portion as means for detecting the gas flow in the drying shaft portion 1. Installed. The signal detected by the gas flow detection means 7 is input to the control means, and the gas flow is made uniform by controlling the air volume of the grate portion, the air temperature, the air flow balance and / or the control end of the grate speed.

  The grate portion 2 includes a grate that further decomposes the waste dried and pyrolyzed by the drying shaft portion 1 to generate a pyrolysis residue and moves it to the pyrolysis residue melting portion 3. The grate part 2 is formed by combining the movable grate 8 and the fixed grate 9 alternately in a staircase shape or an inclined shape, like the stoker furnace. The waste on the grate is advanced from the upstream side to the downstream side while being agitated by reciprocating at a constant pitch in the front-rear direction with a driving device such as a cylinder. The grate portion 2 is blown from below. By adopting the grate structure, the supply of the pyrolysis residue 7 to the pyrolysis residue melting portion 3 becomes continuous and stable, and it is possible to ensure stable melting of the pyrolysis residue in the pyrolysis residue melting portion 3. It becomes possible.

  The pyrolysis residue melting part 3 includes a lower hearth part 10, a morning glory part 11 connected to the hearth part 10, and a shaft part 12 on the morning glory part 11. The shaft portion 12 may not be provided. The furnace floor portion 10 includes a lower tuyere 13 for blowing air and oxygen as an oxygen source, and upper tuyere 14 and 15 for blowing air from the morning glory portion 11 to the lower end portion of the shaft portion 12. In the hearth part 10 of the pyrolysis residue melting part 3, a coke bed is formed in the same manner as a conventional shaft furnace type waste melting furnace, and a hot water outlet 16 for pouring the melt is formed.

  Auxiliary materials such as coke and limestone are input from the auxiliary material inlet 17 at the top of the pyrolysis residue melting portion 3.

  In the above-described configuration, the grate portion 2 and the pyrolysis residue are melted into the waste filling layer 6 formed by introducing waste into the drying shaft portion 1 from the waste inlet 4 at the top of the drying shaft portion 1. When the exhaust gas generated in the section 3 passes, heat exchange is performed, and it becomes possible to improve the efficiency of drying and pyrolysis of waste. The exhaust gas that has passed through the waste filling layer 6 of the drying shaft portion 1 is exhausted from the exhaust gas outlet 5.

  The waste dried and pyrolyzed by the drying shaft portion 1 is further pyrolyzed by the grate portion 2 to generate a pyrolysis residue 18. The generated pyrolysis residue 18 is dropped and filled from the exit side of the grate portion 2 into the pyrolysis residue melting portion 3, burned and melted by the heat source of the coke bed, and discharged from the tap 16 of the hearth portion 10. Discharged.

  In the present invention, the amount of air blown from the grate portion 2 and the air temperature based on the gas flow in the drying shaft portion 1 grasped by the detection means 7 such as a thermometer or thermography installed in the drying shaft portion 1. By making the gas flow in the drying shaft portion 1 uniform by changing factors such as the air flow balance and the grate speed, it is possible to exchange heat appropriately between the furnace gas and the waste in the drying shaft portion, It is possible to minimize the amount of external fuel used such as coke.

  When one part of a thermometer installed as a gas flow detecting means 7 on the drying shaft 1 becomes very hot and a drift of the gas flow is detected, the hot gas generated in the grate 2 is in that part. It can be seen that it flows locally. In order to suppress such a local flow, for example, by changing the amount of air blown from the grate, the gas flow to a part having a low temperature is increased, or the grate speed of a part having a large temperature rise is changed. Thus, the gas flow at the drying shaft portion can be made uniform.

  In order to change the blowing amount, the blowing balance, and the grate speed and make the gas flow in the drying shaft uniform, it is desirable that the grate portion has a structure of two or more stages, and each has a driving device.

1: Drying shaft part 2: Grate part 2a: Front grate group 2b: Rear grate group 3: Pyrolysis residue melting part 4: Waste inlet 5: Exhaust gas outlet 6: Waste packed bed 7: Gas flow detection means 8: movable grate 9: fixed grate 10: hearth 11: morning glory 12: shaft 13: lower tuyere 14: upper tuyere 15: upper tuyere 16: outlet 17: subsidiary material Inlet 18: Thermal decomposition residue

Claims (5)

A grate and pyrolysis residue melting part that generates pyrolysis residue in a waste packing layer formed by charging waste into the drying shaft part from the top of the drying shaft part for drying and pyrolyzing waste Waste gas is dried and pyrolyzed by passing the gas generated in the pyrolysis residue melting part that melts the pyrolysis residue using the coke bed formed by adding coke and limestone from the auxiliary material inlet at the top of the At the same time, the gas that has passed through the waste packed bed is discharged from the top of the drying shaft part, and the waste dried by the drying shaft part is pyrolyzed at the grate part to produce a pyrolysis residue, and the generated pyrolysis The residue is continuously supplied from the grate part to the pyrolysis residue melting part and melted,
Disposal characterized in that the gas flow in the drying shaft portion is detected and the gas flow in the drying shaft portion is made uniform by changing the amount of air blown from the grate portion, the air blowing temperature, the air flow balance and / or the grate speed. Material melting treatment method. 2. The waste melting method according to claim 1, wherein the gas flow detection is a gas temperature or a waste temperature. A waste charging inlet and exhaust gas exhaust outlet are provided at the top, and the gas generated in the grate part and pyrolysis residue melting part is passed through the waste filling layer formed by charging waste from the waste charging inlet. And drying and thermally decomposing the waste, and the drying shaft portion through which the gas passing through the waste packed bed is discharged from the exhaust gas exhaust port,
A grate part connected to the lower part of the drying shaft part and pyrolyzing the waste material dried by the drying shaft part to produce a pyrolysis residue;
Coke bed that is formed by introducing coke and limestone into the pyrolysis residue supplied from the grate part to the auxiliary material inlet at the top of the pyrolysis residue melting part. And a pyrolysis residue melting part that is melt-processed using as a heat source are sequentially arranged,
Gas flow in the drying shaft portion having detection means for detecting the gas flow in the drying shaft portion, and changing the air volume, air temperature, air flow balance and / or grate speed from the grate portion according to the detection signal A waste melting apparatus characterized by having a control means for making uniform. The waste melting apparatus according to claim 3, wherein the detecting means is a thermometer. The waste melting apparatus according to claim 3, wherein the detecting means is a thermography.

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