JP4707435B2 - Stoker-type pyrolysis furnace - Google Patents

Description

  The present invention is a stalker-type pyrolysis capable of generating fuel gas from combustible waste and using it as a heat source when incinerating combustible waste such as municipal waste, industrial waste made of wood chips and waste plastic, etc. It relates to the furnace.

  A stalker furnace consists of a grate group inclined in a staircase pattern, and a pusher for flowing down the incinerated material is provided at each stage of the grate group, burning the incinerated material charged from the top, and It is incinerated while being pushed out with a pusher as appropriate and flowing down to the lower stage, and the width of the grate can be freely changed in accordance with the processing capacity of the incinerated products, so it is widely used for incineration of municipal garbage.

  In this stalker furnace, combustion air is supplied from a grate to burn the incinerated product, and the supply of combustion air cools the grate and protects it from heat.

  In this stalker furnace, fly ash is generated, and a large amount of dioxin is likely to be generated. Therefore, as shown in Patent Document 1, the amount of air supplied into the stalker furnace is controlled, the waste is partially burned, and the heat In order to produce a combustible gas by thermally decomposing the waste, a gasification and melting apparatus for waste that completely burns the combustible gas and the carbides left by the thermal decomposition has been proposed.

Japanese Patent Laid-Open No. 2004-2005

  However, since the gasification and melting apparatus of Patent Document 1 blows combustion air from a grate and simultaneously performs partial combustion and gasification by thermal decomposition while cooling the grate, generation of CO due to incomplete combustion is large. There is a problem that combustible gas is little generated due to thermal decomposition of dust, and there is a problem that the amount of combustion air cannot flow sufficiently to cool the grate.

  An object of the present invention is to provide a stalker type pyrolysis furnace capable of generating combustion gas satisfactorily by thermally decomposing dust using a stalker type furnace.

  In order to achieve the above object, according to the first aspect of the present invention, in a pyrolysis furnace that generates fuel gas by pyrolysis while partially burning garbage, a grate group is formed in a step shape on a water pipe wall. In addition, a pusher that pushes dust down to each stage is provided, a dust throwing means is provided above the upper grate, and a combustion air supply means is provided to the lower grate. .

  According to a second aspect of the present invention, the combustion air supply means is provided so as to blow the combustion air from the lowermost grate to the one to several grate from the lowermost grate. It is.

  According to a third aspect of the present invention, the dust throwing means comprises a hopper for storing garbage and a rotary feeder, a two-stage damper, etc. for shutting off the fire in the furnace connected to the lower part of the hopper. Type pyrolysis furnace.

  The invention according to claim 4 is characterized in that the ceiling wall of the furnace body is inclined substantially the same as the inclination of the stepped grate group, and the staling type is formed so as to reflect radiant heat to the grate by the inclined wall. It is a pyrolysis furnace.

  The invention according to claim 5 is the stalker-type pyrolysis furnace according to claim 3, wherein an exhaust port for the generated fuel gas is provided in the ceiling wall of the furnace body located on the upper side of the stepped grate.

  In the invention of claim 6, the pyrolysis zone is formed from the upper grate to the lower grate, the combustion zone is formed from the lower grate to the lower grate, and the combustion generated in the combustion zone The stalker-type pyrolysis furnace according to claim 1, wherein the waste in the pyrolysis zone is pyrolyzed by heat, and the char remaining after pyrolysis is burned in the combustion zone.

  The invention according to claim 7 is connected to a means for supplying hot water or the like as cooling water to the water pipe wall so that the temperature of the water pipe wall constituting the grate is equal to or higher than the acid dew point temperature of hydrochloric acid, sulfuric acid or the like. The stalker-type pyrolysis furnace according to 1.

  The invention according to claim 8 is a water-cooled screw conveyor or the like in which an ash discharge portion extending in the width direction is formed in a furnace body located below the lowermost grate, and incombustible materials such as ash are carried into the ash discharge portion. The stalker-type pyrolysis furnace according to claim 6, wherein a discharge means is provided.

  The invention according to claim 9 is the stalker type pyrolysis furnace according to claim 8, wherein the ash discharge portion formed in the furnace body is formed so as to be isolated from the combustion zone.

  According to a tenth aspect of the present invention, in a pyrolysis furnace that generates fuel gas by pyrolysis while partially burning garbage, a staircase grate group is formed on the water tube wall in the furnace body, and at each stage thereof A pusher that pushes the dust down is provided, dust input means is provided above the upper grate, combustion air supply means is provided in the lower grate, and a combustion zone is provided in the lower furnace body of the grate group. A pyrolysis zone is formed in the upper furnace body of the grate group, and incombustibles such as ash pushed out by the pusher from the lower grate are sent to the ash melting furnace etc. A stalker-type pyrolysis furnace with a drop opening.

  The invention according to claim 11 is the stalker-type pyrolysis furnace according to claim 10, wherein the furnace body above the drop opening is provided with an openable / closable door that partitions the drop opening from the combustion zone.

  The invention of claim 12 is the stalker-type pyrolysis furnace according to claim 11, wherein a plurality of pushers are provided side by side in the width direction of the water tube wall, and a plurality of doors are provided in accordance with the width of the pusher at the final stage. .

  In the present invention, a staircase grate group is formed on the water pipe wall, combustion air is supplied to the lower side of the grate to burn the char remaining after pyrolysis, and the combustion heat is generated on the upper side with the combustion heat. By performing the thermal decomposition, there is an advantage that most of the garbage can be used as combustion gas and used as fuel.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

  In FIG. 1, reference numeral 10 denotes a furnace body made of a refractory material. A bottom portion 11 is formed in a staircase shape, an upper wall 12 is provided on the upper stage side of the bottom portion 11, and a lower wall 13 is disposed on a lower stage side of the bottom portion 11. The side wall 14 is provided on both sides of the bottom portion 11, and the ceiling wall 15 is formed of the inclined wall portion 15 i and the horizontal wall portion 15 h from the lower wall 13 to the upper wall 12.

  The ceiling wall 15 on the upper wall 12 side is provided with a dust feeder 18 comprising a rotary feeder 16 in which a casing 16c is formed of a refractory material and a hopper 17 provided on the rotary feeder 16. The dust input means 18 may be, for example, a two-stage damper or an L-shaped hopper on the upper wall 12 and the ceiling wall 15 as long as dust can be input in a sealed state without using the rotary feeder 16. May be configured such that the fire and the outside air side of the furnace body 10 are sealed with the dust introduced into the hopper, and the dust is pushed out by a dust input pressure, a screw feeder, or the like.

  A U-shaped ash discharge part 19 extending in the width direction is formed on the lower wall 13 so as to be located behind the surface of the lower wall 13, and the ash discharge part 19 is provided with discharge means such as a water-cooled screw conveyor. 20 is provided.

  An exhaust port 21 for exhausting the generated fuel gas and combustion exhaust gas is provided in the horizontal wall portion 15 h of the ceiling wall 15.

  A water pipe wall 22 is provided on each step portion 11 s of the step-like bottom portion 11 to form a step-like grate group 23. Each step 11s is formed so as to be inclined forward by 3 to 5 °.

  The water pipe wall 22 is provided so as to be embedded in the floor surface 11f of the stepped portion 11s, extends from the floor surface 11f so as to cover the upper surface of the lower stepped portion 11s, and then is folded to return the vertical surface 11v of the stepped portion 11s. To be reached.

  Between the water pipe wall 22 protruding from the step 11s and the water pipe wall 22 of the lower step 11s, a pusher 24 for pushing out dust as incinerated material is provided by a cylinder 25 so as to freely advance and retreat.

  FIG. 2 is a diagram showing details of the water pipe wall 22 and the pusher 24. The water pipe wall 22 is formed by arranging a large number of water pipes 22p and welding a flat bar 22f on the upper part between the water pipes 22p. A plurality of pushers 24 are provided side by side in the width direction of the water pipe wall 22. These pushers 24 are formed by providing a refractory material 24f on a heat-resistant metal plate 24d that moves in contact with the flat bar 22f, or are all made of heat-resistant steel.

Each stage water pipe wall 22 is connected so that cooling water flows from the lower stage to the upper stage, and the cooling water supply means 26 is connected to the lowermost water pipe wall 22b. Although not shown, the gas is discharged from the line 27 through the upper wall 12 and the casing 16c of the rotary feeder 16, and is circulated to the cooling water supply means 26 again after being cooled by evaporation due to pressure reduction at the restriction orifice 28. The restriction orifice 28 connected to the line 27 adjusts the inside of the water pipe wall 22 to a pressure at which the water pipe wall 22b does not evaporate even at an acid dew point temperature or higher (180 ° C. or higher) such as sulfuric acid or hydrochloric acid. May have a structure used as part of a boiler having a pressure of 10 kg / cm ² G or more.

  Combustion air supply means 28 is provided on the lowermost water pipe wall 22b of the grate group 23 and the water pipe wall 22 immediately above it. In the combustion air supply means 28, a combustion air line 30 is connected to a fan 29. The line 30 is branched into, for example, three branches, and water is supplied from the branch lines 30a and 30b as shown by arrows 31a and 31b in the drawing. Combustion air is blown from the pipe wall 22 and from the branch line 30c through the lower wall 13 to the lowermost water pipe wall 22b as shown by an arrow 31c in the figure.

  When the combustion air is blown from the water pipe wall 22, in the example shown in the drawing, it is blown toward the lowermost water pipe wall 22b as shown by an arrow 31b and into the upper water pipe wall 22 as shown by an arrow 31a. However, it may be blown toward the water pipe wall 22 one to four stages above the lowest stage.

  In addition, when injecting combustion air, if ash is blown upward as in the past, ash tends to fly into air ash and blown downward toward the water tube wall 22 to suppress the generation of fly ash. Can do. When air is blown upward, the nozzle hole is a round hole of 5 mm or less.

  Pressure gauges 32, 33a, 33b, 33c are connected to the line 30 and branch lines 30a, 30b, 30c, and valves 34a, 34b, 34c are connected to the branch lines 30a, 30b, 30c.

  The lower wall 13 is provided with a combustion burner 35 that burns garbage in the initial stage of operation.

  The ash discharging unit 19 is connected to a conveyor 36 that discharges incombustible materials such as ash conveyed by the discharging means 20.

  The amount of combustion air blown by the combustion air supply means 28 is supplied so that the air ratio is about 1/3 with respect to the dust input from the dust input means 18. Thereby, in the furnace body 10, the combustion zone 37F is formed on the lower side of the grate group 23, and the pyrolysis zone 37D is formed on the upper side of the grate group 23.

  In the above, dust such as wood chips is thrown from the dust throwing means 18 onto the upper water tube wall 22u of the grate group 23, pushed out by the pusher 24 as appropriate, and moved to the lower water tube wall 22.

  In the initial stage of operation, the dust on the lower grate group 23 is burned by the flame from the combustion burner 35. If the dust is stably burned, the combustion burner 35 is stopped and the dust is self-combusted.

  Due to the combustion of the dust, the combustion exhaust gas rises as shown by the arrows 38 f and 38 d shown in the figure and is discharged from the exhaust port 21. At this time, the dust on the grate group 23 in the thermal decomposition zone 37D is heated by the heat of the combustion exhaust gas and the radiant heat from the inclined wall portion 15i of the ceiling wall 15 of the furnace body 10, and the combustible component is thermally decomposed. The fuel gas is discharged from the exhaust port 21 together with the combustion exhaust gas. Since this fuel gas is produced in a larger amount than the amount of combustion exhaust gas, it can be used as fuel.

  In this way, the waste is sequentially transferred to the lower stage by the pushers 24 through the water pipe walls 22 of the grate group 23, and is reduced in volume while being thermally decomposed to produce fuel gas in the pyrolysis zone 37D. Most of the carbon is carbonized while reaching the lattice group 23 to become char. This char is burned by the combustion air supplied by the combustion air supply means 28 from the lower stage of the grate group 23 as indicated by arrows 31a and 31b. While the combustion exhaust gas is discharged from the exhaust port 21, the heat of the combustion gas is used for the thermal decomposition of the dust in the thermal decomposition zone 37D.

  Since the char on the water cooling wall 22b in the vicinity of the lowermost stage burns, even if the temperature of the water pipe wall 22b is 100 ° C., for example, the acid dew point does not decrease.

  Incombustibles such as ash remaining on the lowermost water pipe wall 22b are discharged to the ash discharge unit 19 by the pusher 24, discharged to the outside of the furnace body 10 by the screw conveyor 20, and transferred to the subsequent process by the conveyor 36. Is done.

  The water pipe wall 22 of each stage of the grate group 23 is constantly cooled by the cooling water supplied from the cooling water supply means 26 and is protected from combustion heat and the like. At this time, the cooled cooling water discharged from the line 27 is controlled by the restriction orifice 28, and the temperature of the water pipe wall 22 is maintained at a pressure that does not evaporate even at 180 ° C. above the acid dew point temperature such as sulfuric acid and hydrochloric acid. Thus, acid corrosion of the water pipe wall 22 can be prevented.

  By keeping the water pipe wall 22 near 180 ° C. in this way, the ash is not melted even if dust is burned, and the adverse effect that the melt adheres to the grate group 23 is eliminated.

  FIG. 3 shows another embodiment of the present invention.

  In the embodiment of FIG. 1, the form in which the incombustible material such as ash is transferred to the subsequent process by the discharging means 20 is shown. In this embodiment, the incombustible material remaining in the final stage water pipe wall 22 b is removed from the melting furnace. It is made into a pyrolysis furnace suitable for being discharged to the like and melted and granulated.

  That is, a vertical wall 40 is formed below the bottom 11 on the lowermost side of the furnace body 10, a horizontal wall 41 is provided below the lower wall 13, and a vertical wall 42 is formed on the horizontal wall 41, so that the bottom 11 side The vertical wall 40 forms a drop opening 43, and an ash melting furnace (not shown) is connected below the drop opening 43.

  The incombustible material remaining on the final-stage water pipe wall 22 b is pushed out by the final-stage pusher 24 b and discharged to the dropping port 43. At this time, the horizontal wall 41 is provided with a door 44 that partitions the drop port 43 and the combustion zone 37F so as to be rotatable in the direction of the arrow shown in the drawing. A plurality of the doors 44 are provided side by side so as to have a width corresponding to the width of the final stage pusher 24b. The doors 44 are individually opened and closed, and the non-combustible material at the portion pushed out by the pusher 24b is transferred to the corresponding door 44. Is opened and dropped to the drop opening 43.

  Further, the combustion air supply means 28 blows out from the upper water pipe wall 22 of the lowermost water pipe wall 22b toward the lower water pipe wall 22b as shown by the arrow 45a in the figure, and the lower wall 13 To the lowermost water pipe wall 22b as shown by an arrow 45c.

  In this embodiment, incombustibles such as ash remaining on the lowermost water pipe wall 22b are dropped to the dropping port 43 by the lowermost pusher 24b and supplied to an ash melting furnace (not shown) to melt the ash. In a furnace, fuel gas generated by pyrolysis is used as a heat source to melt non-combustible materials, which are divided into appropriate sizes and water-cooled, so that they can be granulated and used as building materials.

  As described above, in the present invention, the staggered stalker-type grate group 23 is used, each stage of the grate group 23 is formed by the water pipe wall 22, pyrolyzed at the upper stage, and debris at the lower stage. By burning char obtained by pyrolysis, most of the waste can be used as fuel gas for other heat sources. Moreover, since it is only necessary to burn the char remaining after pyrolysis, the generation of fly ash in the furnace body 10 is small, and the generation of dioxins can be suppressed.

  In addition, since pyrolysis and combustion are performed while moving dust sequentially to the lower stage using the stair-like stalker-type grate group 23, thermal decomposition and combustion control can be performed accurately. Furthermore, since the width and the number of stages of the grate group 23 can be freely changed, it is possible to optimally control the pyrolysis and combustion in accordance with the amount of waste and the quality of dust.

It is sectional drawing which shows one embodiment in this invention. It is the sectional view on the AA line of FIG. It is principal part sectional drawing which shows other embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Furnace 18 Dust input means 22 Water pipe wall 23 Grate 24 Pusher 26 Combustion air supply means

Claims (12)

  In a pyrolysis furnace that generates fuel gas by pyrolysis while partially combusting garbage, a grate group is formed in a staircase shape on the water tube wall, and a pusher that pushes the dust down to each stage is provided. A stalker-type pyrolysis furnace characterized in that dust input means is provided above the upper grate and combustion air supply means is provided on the lower grate.   The stalker-type pyrolysis furnace according to claim 1, wherein the combustion air supply means is provided so as to blow out combustion air from the lowermost grate and from one to several grate.   2. The stalker-type pyrolysis furnace according to claim 1, wherein the dust throwing means comprises a hopper for containing garbage and a rotary feeder, a two-stage damper, etc. for cutting off the fire in the furnace connected to the lower part of the hopper.   The stalker-type pyrolysis furnace according to claim 1, wherein the ceiling wall of the furnace body is inclined substantially the same as the inclination of the step-like grate group, and the radiant heat is reflected by the inclined wall to the grate.   The stalker-type pyrolysis furnace according to claim 3, wherein an exhaust port for the generated fuel gas is provided on the ceiling wall of the furnace body located on the upper side of the staircase grate.   A pyrolysis zone is formed from the upper grate to the lower grate, a combustion zone is formed from the lower grate to the lower grate, and the combustion heat generated in the combustion zone The stalker-type pyrolysis furnace according to claim 1, wherein waste is pyrolyzed, and char remaining after pyrolysis is burned in the combustion zone.   The stalker-type pyrolysis according to claim 1, wherein means for supplying hot water or the like as cooling water to the water pipe wall is connected so that the temperature of the water pipe wall constituting the grate is equal to or higher than an acid dew point temperature of hydrochloric acid, sulfuric acid or the like. Furnace.   An ash discharge portion extending in the width direction is formed in the furnace body located below the lowermost grate, and discharge means such as a water-cooled screw conveyor for carrying incombustibles such as ash is provided in the ash discharge portion. Item 7. The stalker-type pyrolysis furnace according to item 6.   The stalker-type pyrolysis furnace according to claim 8, wherein the ash discharge portion formed in the furnace body is formed so as to be isolated from the combustion zone.   In a pyrolysis furnace that generates fuel gas by pyrolysis while partially burning garbage, a staircase grate group is formed in the furnace body with a water pipe wall, and pushers that push the garbage down to the respective stages are formed. Provided with dust input means above the upper grate, provided combustion air supply means on the lower grate, and set the combustion zone in the lower furnace body of the grate group on the upper side of the grate group A pyrolysis zone was formed in the furnace body of the bottom, and a drop opening was formed in the furnace body of the lower grate to send incombustibles such as ash pushed out from the bottom grate to the ash melting furnace etc. A characteristic stalker-type pyrolysis furnace.   The stalker-type pyrolysis furnace according to claim 10, wherein the furnace body on the dropping port is provided with an openable and closable door that partitions the dropping port and the combustion zone.   The stalker-type pyrolysis furnace according to claim 11, wherein a plurality of pushers are provided side by side in the width direction of the water tube wall, and a plurality of doors are provided side by side in accordance with the width of the pusher at the final stage.

Images