JP5931593B2 - Stair-type incinerator - Google Patents

Description

The present invention relates to an improvement of a stair-type incinerator that burns high moisture content fuel such as sludge, food residue, garbage, and high moisture content fuel such as scum, chip dust, bark, bagasse on a stoker, In particular, waste water and fuel with a high water content can be burned without providing expensive equipment such as a dryer, and a certain amount of ammonia gas can be removed, so nitrous oxide, one of the typical greenhouse gases ( The present invention relates to a step-type incinerator in which the generation of N ₂ O) is reduced, the deodorizing effect is enhanced, and the combustion gas temperature with less generation of dioxins (DXNs) can achieve 850 ° C. or higher.

  In general, waste and fuel having a high water content are incinerated by dehydrating and drying them and then putting them into a stoker-type incinerator or fluidized-bed incinerator (for example, Patent Document 1, Patent) Reference 2 and Patent Document 3).

  By the way, when incinerating waste and fuel with high water content in a stoker-type incinerator or fluidized-bed incinerator, in order to minimize dioxins, nitrous oxide, odor, etc. in the complete combustion and combustion exhaust gas The combustion temperature in the furnace needs to be 850 ° C. or higher.

However, because the high moisture content waste and fuel contain a lot of moisture, the combustion temperature in the furnace does not exceed 850 ° C., and fuel such as kerosene and LPG is required as auxiliary fuel, Or it was necessary to install a dryer such as sludge, and it was difficult to use energy by recovered heat.
In particular, since the sewage sludge after dehydration has a water content of about 80%, a new dryer or an air heater or a large amount of auxiliary fuel is required to reduce the volume by combustion.

  FIG. 5 shows an example of an incineration plant equipped with a conventional step-type incinerator that incinerates high moisture content waste and fuel, and FIG. 6 shows a conventional fluidized bed that incinerates high moisture content waste and fuel. 1 shows an example of an incineration plant equipped with an incinerator.

  As shown in FIG. 5, the former incineration plant is composed of a stepped incinerator 30, a boiler 31, a dust collector 32, a gas cleaning tower 33, an induction fan 34, a chimney 35, a sludge dryer 46, and the like. Waste and fuel with a moisture content, for example, dewatered sludge S, is dried in the sludge dryer 46 and incinerated in the step-type incinerator 30 to reduce and reduce the volume, and is generated in the step-type incinerator 30. The hot combustion gas G and heated steam H are recovered by the boiler 31 and passed through a dust collector 32 and a gas cleaning tower 33 to form a clean gas, which is then discharged from the chimney 35 through the induction fan 34 into the atmosphere. It is what I did.

  Further, the stepped incinerator 30 includes a furnace main body 36, a stalker 37 including a dry stalker 37a and a combustion stalker 37b, a hopper 38 below the stalker, a supply feeder 39, a primary combustion air supply duct 40, a secondary combustion air supply duct 41, a combustion Air fan 42, air heater 43, auxiliary burner 44, ash discharge conveyor 45, steam-heated sludge dryer 46, scrubber 47, carrier gas heater 48, carrier gas fan 49, sludge supply conveyor 50, etc. ing.

Thus, according to the step-type incinerator 30, the sludge S that has been dehydrated by the dehydrator and reduced the water content to some extent (reduced to about 80%) is water content by the steam-heated sludge dryer 46. After being dried to about 40%, the sludge is fed to the feed feeder 39 by the sludge feed conveyor 50, and is quantitatively fed into the furnace by the feed feeder 39, heated and dried on the dry stoker 37a, and the combustion stoker 37b. It is supposed to burn completely above.
Further, in the sludge dryer 46, moisture (vapor) and ammonia gas evaporated from the sludge S are sent to the scrubber 47 together with the carrier gas, where moisture (vapor) and ammonia gas are removed, and only the carrier gas is sludge dried. Return to the machine 46.

  By the way, in the step-type incinerator 30, since the sludge S from which moisture has been removed to about 40% is burned, it is easy to keep the combustion temperature in the furnace at 850 ° C. or higher.

However, the above-described step-type incinerator 30 requires a sludge dryer 46 and a steam supply system to the sludge dryer 46, which is expensive equipment and is used for installing the sludge dryer 46, the scrubber 47, and the like. There was a problem that a new space was needed.
Moreover, since about 80% of the steam generated in the boiler 31 is consumed by the sludge dryer 46 and the carrier gas heater 48, there is a problem that surplus steam is reduced.

  On the other hand, as shown in FIG. 6, the latter incineration plant includes a fluidized bed incinerator 51, an air heater 52, a combustion air fan 53, a cooling tower 54, a dust collector 55, a gas cleaning tower 56, an induction fan 57 and A chimney 58 or the like is used to incinerate a high water content waste or fuel, for example, dewatered sludge S, in the fluidized bed incinerator 51, and the high temperature combustion gas G generated in the fluidized bed incinerator 51. The heated water vapor H is recovered by the air heater 52, cooled by the cooling tower 54, passed through the dust collector 55 and the gas cleaning tower 56 to be clean gas, and then passed through the induction fan 57 from the chimney 58. It is designed to be released into the atmosphere.

  The fluidized bed incinerator 51 includes a furnace main body 59, a fluidized bed 60 made of a fluid medium such as silica sand, a fluidized bed aeration nozzle (not shown), a supply feeder 61, an auxiliary burner 62, and the like.

  Thus, according to the fluidized bed incinerator 51, the dehydrated sludge S having a water content of about 80% is quantitatively supplied from the supply feeder 61 into the furnace, and in the fluidized bed 60 the fluidized bed aeration. Combustion is performed while being mixed and agitated with a fluid medium flowing by combustion air ejected from a nozzle.

By the way, in the fluidized bed incinerator 51, the combustion air heated to about 500 ° C. by the air heater 52 is sent to the fluidized bed 60, but the moisture contained in the sludge S is evaporated and burned. In order to raise the temperature to 850 ° C. and maintain the temperature, auxiliary combustion by the auxiliary burner 62 was necessary.
Therefore, in the fluidized bed incinerator 51, there is a problem that a large amount of auxiliary fuel is required for the auxiliary burner 62 and the running cost increases.
Further, since the combustion air supplied to the fluidized bed 60 is heated by the combustion gas G and the heated water vapor H by the air heater 52, the temperature of the combustion gas at the outlet of the air heater 52 becomes about 250 ° C., and the boiler However, it was difficult to install a boiler because the temperature was too low for heat recovery.
Furthermore, since the ammonia contained in the sludge S is not removed before combustion, the entire amount becomes combustion gas, and nitrous oxide (N ₂ O), which is a greenhouse gas, and NOx, which is an acidic gas, are generated. There was a problem.
In addition, since the water vapor H of the evaporated sludge S is not aggregated and is contained in the exhaust gas, all of it passes through the exhaust gas treatment facility, and the capacity of the exhaust gas treatment facility and the induction fan is increased and the power consumption is accordingly increased. There was a problem that the amount was high.

JP 61-134519 A Japanese Patent Laid-Open No. 11-063458 JP 2004-278950 A

The present invention has been made in view of such problems, and its purpose is to burn waste and fuel having a high water content without providing expensive equipment such as a dryer, and to some extent ammonia. Since the gas can be removed, the generation of nitrous oxide (N ₂ O), one of the typical greenhouse gases, is reduced, the deodorizing effect is enhanced, and the combustion gas temperature is low in the generation of dioxins (DXNs). The object is to provide a stepped incinerator capable of achieving 850 ° C. or higher.

In order to achieve the above object, the invention of claim 1 of the present invention comprises a stoker comprising a dry stoker and a combustion stoker, and supplies primary combustion air from below the stoker to a primary combustion chamber above the stoker and supplies it onto the stoker. have been causes a primary combustion of the waste and fuel high water content, in the stepped incinerator so as to secondarily burn the unburnt gas and unburnt in the secondary combustion chamber of the primary combustion chamber above the The stair-type incinerator draws the primary combustion air that is supplied under the dry stoker and passes through the waste and fuel on the dry stoker together with the steam and ammonia gas generated on the dry stoker, and only the primary combustion air is extracted from the secondary combustion air. As a secondary combustion air supply path for supplying to the secondary combustion chamber, and a cleaning tower that is interposed in the secondary combustion air supply path and that condenses and removes steam and ammonia gas extracted together with the primary combustion air There are particular feature comprises a.

The invention of claim 2 of the present invention comprises a stoker comprising a dry stoker and a combustion stoker, and waste having a high water content supplied on the stoker by supplying primary combustion air from the bottom of the stoker to the primary combustion chamber above the stoker And a stepwise incinerator in which unburned gas and unburned substances are secondarily burned in a secondary combustion chamber above the primary combustion chamber, and the stepped incinerator is a stepped incinerator. An exhaust gas supply passage that extracts a part of the exhaust gas from the exhaust gas exhaust line of the incinerator and supplies it to the dry stoker, and the exhaust gas that has passed through the waste and fuel on the dry stoker is extracted along with the vapor and ammonia gas generated on the dry stoker. The exhaust gas recirculation path that supplies only the exhaust gas as the recirculation gas to the secondary combustion chamber and the exhaust gas recirculation path, which condenses the steam and ammonia gas extracted along with the exhaust gas Particular and a wash column to remove Te is characterized.

According to the third aspect of the present invention, the exhaust gas or the primary combustion air that has passed through the waste or fuel on the dry stoker and the steam or ammonia gas generated on the dry stoker are located above the dry stoker on the secondary combustion chamber side. It is characterized by the provision of a radiating plate that prevents the waste from flowing to the waste and also gives radiant heat to the waste and fuel on the dry stoker .

The stepped incinerator according to the reference example of the present invention draws a part of the exhaust gas from the exhaust gas discharge line of the stepped incinerator and supplies this to the bottom of the dry stoker so that the waste with high water content on the dry stoker can be removed. The exhaust gas that has been dried and passed through the dry stoker and waste is drawn out together with the steam and ammonia gas generated on the dry stoker and returned to the exhaust gas discharge line, so the combustion gas temperature in the furnace is 850 ° C or higher it is possible to increase, it is possible to some extent removed before the combustion of ammonia contained in the waste (30% removal).

As a result, the step-type incinerator according to the reference example of the present invention requires a dryer for drying waste having a high water content and a steam supply system to the dryer as in the conventional step-type incinerator. In addition, waste with high water content can be burned without providing expensive equipment such as a dryer, and installation space for the dryer is not required, and excess steam is increased.
Further, the stepped incinerator according to the reference example of the present invention can raise the combustion gas G temperature to 850 ° C. or more by extracting steam from above the dry stoker, so that no auxiliary combustion by the auxiliary burner is required, and The consumption can be reduced and the running cost can be reduced.
Furthermore, the stepped incinerator according to the reference example of the present invention can raise the combustion gas temperature in the furnace to 850 ° C. or more, and can remove ammonia contained in the waste before combustion. Therefore, the generation of nitrous oxide (N ₂ O), which is a greenhouse gas, and NOx, which is an acidic gas, is reduced, and the deodorizing effect is enhanced.

The stepped incinerator according to claim 1 of the present invention draws the primary combustion air that has passed through the dry stoker and the waste on the dry stoker together with the steam and ammonia gas generated on the dry stoker, The ammonia gas is removed by the cleaning tower, and only the primary combustion air is supplied to the secondary combustion chamber as the secondary combustion air, so that the combustion gas temperature in the furnace can be raised to 850 ° C. or more and discarded. Ammonia contained in the object or the like can be removed before combustion, and the same effects as the step-type incinerator shown in FIG. 1 can be achieved.
In particular, the step-type incinerator according to claim 1 of the present invention is installed in the exhaust gas discharge line because water (vapor) and ammonia gas evaporated by drying of wastes and the like are condensed and removed by the cleaning tower. The capacity of the gas cleaning tower can be reduced. Also, running costs can be reduced.

The stepped incinerator according to claim 2 of the present invention draws a part of the exhaust gas from the exhaust gas discharge line of the stepped incinerator and supplies it to the bottom of the dry stoker so that the waste with high water content on the dry stoker can be removed. The exhaust gas that has been dried and passed through the dry stoker and waste, etc. is drawn out together with the vapor and ammonia gas generated on the dry stoker, and the vapor and ammonia gas in the exhaust gas are removed by a washing tower, and only the exhaust gas is used as recirculation gas. Since it is supplied to the secondary combustion chamber, the combustion gas temperature in the furnace can be raised to 850 ° C. or higher, and ammonia contained in the waste can be removed before combustion. The same effects as the stepped incinerator shown in FIG.
In particular, the step-type incinerator according to claim 2 of the present invention is installed in the exhaust gas discharge line because water (vapor) and ammonia gas evaporated by drying of wastes and the like are condensed and removed by the cleaning tower. The capacity of the gas cleaning tower can be reduced.
In the stepped incinerator according to claim 2 of the present invention, the exhaust gas extracted from above the dry stoker is supplied to the secondary combustion chamber 13 as the recirculation gas, so that NOx can be reduced.

In the stepped incinerator according to claim 3 of the present invention, since the radiation plate is disposed above the drying stoker, the waste on the drying stoker can be reliably and satisfactorily dried by radiant heat, and It is possible to prevent the exhaust gas or the primary combustion air above the dry stoker, the steam and the ammonia gas from flowing to the secondary combustion chamber side, and the steam and the ammonia gas can be satisfactorily extracted.

It is a schematic system diagram of the incineration plant provided with the step type incinerator concerning the reference example of the present invention. It is explanatory drawing which showed the effect which draws out the vapor | steam above dry stoker, (A) shows the case (equivalent to the conventional step type incinerator) when the whole quantity of the vapor | steam evaporated in sludge is mixed with combustion gas, (B ) Shows the case where the evaporated vapor in the sludge is extracted (corresponding to the stepped incinerator of the present invention). 1 is a schematic system diagram of an incineration plant including a stepped incinerator according to a first embodiment of the present invention. It is a schematic system diagram of the incineration plant provided with the step type incinerator concerning the 2nd Embodiment of this invention. It is a schematic system diagram of the incineration plant provided with the conventional step type incinerator. It is a schematic system diagram of the incineration plant provided with the conventional fluidized bed type incinerator.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an incineration plant using a stepped incinerator 1 according to a reference example of the present invention. The incineration plant uses high moisture content waste or fuel, for example, dehydrated sludge S (hereinafter referred to as sludge S). A stair-type incinerator 1 to be incinerated, connected to an exhaust gas outlet of the stair-type incinerator 1, a boiler 2 that recovers heat from the high-temperature combustion gas G ′ and generates steam, and a boiler 2 connected via a gas duct 3 A dust collector 4 for removing dust in the exhaust gas G ′, and a gas cleaning tower connected to the dust collector 4 via the gas duct 3 for removing acid gases (SOx, HCl, etc.) in the exhaust gas G ′. 5, an induction fan 6 that is connected to the gas cleaning tower 5 via the gas duct 3 and induces the combustion gas G ′ in the step-type incinerator 1, and clean exhaust gas G ′ that has passed through the induction fan 6 into the atmosphere It consists of a chimney 7 that emits.

As shown in FIG. 1, the stepped incinerator 1 includes a furnace body 8, a stair slide type stoker 9 including a drying stoker 9 a for drying and burning sludge S and a combustion stoker 9 b, and a stoker 9. The provided hopper 10 under the stoker, the feed feeder 11 for supplying the sludge S to the stoker 9 in a fixed quantity, the primary combustion chamber 12 formed above the stoker 9, and the secondary combustion formed above the primary combustion chamber 12 Chamber 13, combustion air fan 14 for supplying primary combustion air below combustion stoker 9 b, primary combustion air supply duct 15, and secondary combustion chamber 13 connected to secondary combustion chamber 13 by branching connection to primary combustion air supply duct 15. A secondary combustion air supply duct 16 that supplies combustion air, an air heater 17 that heats the primary combustion air and the secondary combustion air with steam from the boiler 2, and an auxiliary bar that is used when the furnace is started up. , An ash discharge conveyor 19 for carrying out the ash dropped to the hopper 10 under the stoker, and an exhaust gas supply passage for extracting a part of the exhaust gas G ′ from the exhaust gas discharge line of the stepped incinerator 1 and supplying it under the dry stalker 9a 20, a dry carrier fan 21 interposed in the exhaust gas supply passage 20, the dry stoker 9a and the sludge S on the dry stoker 9a, and the carrier gas G ″ flowing above the dry stoker 9a on the dry stoker 9a. An exhaust gas return path 22 that is drawn out together with the generated steam H ₁ and ammonia gas and returned to the exhaust gas exhaust line, and a radiation plate 23 disposed in the primary combustion chamber 12 above the dry stoker 9a, is a stepped incinerator. A part of the exhaust gas G ′ recovered from the exhaust gas exhaust line 1 is pulled out and supplied to the bottom of the dry stoker 9a. Grating and drying stoker is passed through the sludge S on 9a, it is withdrawn from above the water (steam H ₁₎ and ammonia gas with dry stoker 9a in the sludge S evaporation of the carrier gas G "passing through the sludge S exhaust gas discharge line The exhaust gas is treated by the dust collector 4 and the gas cleaning tower 5 together with the exhaust gas G ′ flowing through the exhaust gas discharge line.

  The exhaust gas supply path 20 has one end connected to the gas duct 3 connecting the boiler 2 and the dust collector 4, and the other end connected to the stalker lower hopper 10 disposed below the dry stoker 9a. It consists of an exhaust gas supply duct 20a and a dry carrier fan 21 interposed in the exhaust gas supply path 20, and a part of the exhaust gas G 'having a temperature of 200 ° C to 250 ° C is pulled out from the exhaust gas discharge line by the suction force of the dry carrier fan 21 The extracted exhaust gas G ′ is supplied as carrier gas G ″ to the dry stoker 9a.

Further, the exhaust gas return path 22 has a trumpet-shaped extraction port 22a formed in the furnace wall above the dry stoker 9a, one end connected to the extraction port 22a, and the other end connected to the boiler 2 and the dust collector 4. The exhaust gas return duct 22b connected to the gas duct 3 and the moisture (steam H ₁ ) in the sludge S that has evaporated the carrier gas G ″ passing through the sludge S on the dry stoker 9a by the suction force of the induction fan 6. Along with the ammonia gas, the carrier gas G ″, the vapor H ₁ and the ammonia gas are extracted from the extraction port 22a above the dry stoker 9a and returned to the exhaust gas discharge line.

The radiation plate 23 is formed of a steel plate material, and is disposed above the drying stoker 9a in a state of projecting from the furnace wall above the drying stoker 9a of the furnace body 8 toward the combustion stoker 9b. The radiation plate 23 prevents the exhaust gas G ′, the vapor H ₁ and the ammonia gas above the dry stoker 9a from flowing to the secondary combustion chamber 13 side, and gives radiant heat to the sludge S on the dry stoker 9a to provide dehydrated sludge. This increases the drying effect of S.
Note that the radiation plate 23 may be omitted when burning wastes and the like containing a large amount of corrosive components such as Cl. In this case, since the radiant heat from the radiation plate 23 cannot be obtained, the dry stoker 9a is lengthened so that the dewatered sludge S on the dry stalker 9a can obtain a large amount of radiant heat from the combustion gas G.
Moreover, you may form the radiation plate 23 with the refractory material excellent in corrosion resistance. In this case, even when a waste containing a lot of corrosive components is burned, the radiation plate 23 may not be omitted, and the drying effect is enhanced by the radiation heat of the radiation plate 23.

  Next, the case where the sludge S is incinerated using the above-described step-type incinerator 1 will be described.

  The sludge S is supplied in a fixed amount onto the dry stalker 9a by the supply feeder 11, is pulled out from the exhaust gas discharge line by the exhaust gas supply path 20 on the dry stalker 9a, and is supplied from below the dry stalker 9a. It is heated and dried by radiant heat from the radiation plate 23 heated by the gas G ″, the combustion gas G and the combustion flame.

Most of the carrier gas G ″ passing through the grate of the dry stoker 9a and the sludge S on the dry stoker 9a and the steam H ₁ and ammonia gas generated by heating and drying the dehydrated sludge S are from above the dry stoker 9a. The exhaust gas is extracted by the exhaust gas return path 22, returned to the exhaust gas exhaust line, and treated with the exhaust gas G ′ flowing through the exhaust gas exhaust line by the dust collector 4 and the gas cleaning tower 5.

The dried sludge S is continuously sent from the dry stalker 9a onto the combustion stalker 9b, burns with the primary combustion air supplied from below on the combustion stalker 9b, and burns completely on the combustion stalker 9b. The ash is dropped and discharged from the ash outlet on the downstream side of the combustion stoker 9b. In FIG. 1, H ₂ is steam generated by the combustion stoker 9b.

  On the other hand, unburned gas and unburned matter in the combustion gas are agitated and mixed by the secondary combustion air in the secondary combustion chamber 13, completely burned, and then discharged from the exhaust gas outlet.

FIG. 2 is an explanatory view showing the effect of extracting the steam above the drying stoker 9a. FIG. 2A shows the case where the entire amount of steam H (H ₁ + H ₂ ) generated from the sludge S is mixed with the combustion gas G (drying). (B) shows that 20% of the steam H ₂ generated in the sludge S is mixed with the combustion gas G, and the remaining 80%. When the steam H ₁ is discharged as the carrier gas G ″ (corresponding to the stepped incinerator 1 of the present invention in which steam is extracted from above the dry stoker 9a), the supply amount of the carrier gas (exhaust gas G ″) is 1000 Nm ^3. / H, temperature was 200 ° C.

The numerical values used for the trial calculation of the conventional step-type incinerator and the step-type incinerator 1 of the present invention are as follows.
Water content of dehydrated sludge S is 78%, calorific value of dehydrated sludge S is 410 kcal / kg (wet sludge S), supply amount of dehydrated sludge S is 1000 kg / h, combustion air is 3430 Nm ³ / h (air ratio is about 1.4) ), The temperature of the combustion air was 150 ° C., the heat release from the incinerator was 2%, and the combustion gas G ′ specific heat was 0.35 kcal / Nm ³ · ° C.
As a result, as is apparent from FIG. 2, while the conventional stepped incinerator 1, the combustion gas G 'temperature is 642 ° C., dried stoker 9a above the stepped of the present invention withdrawal of the steam H ₁ In the incinerator 1, the combustion gas G ′ temperature became 900 ° C., and the combustion gas G ′ temperature could be increased by about 250 ° C.

Thus, the above-mentioned stepped incinerator 1 draws out the carrier gas G ″ at 200 ° C. to 250 ° C. from the exhaust gas discharge line through the exhaust gas supply path 20 and supplies it to the bottom of the dry stoker 9a. The sludge S is dried, and the steam H ₁ and ammonia gas generated on the drying stoker 9a are drawn together with the carrier gas G ″ through the exhaust gas return path 22 and returned to the exhaust gas discharge line. The combustion gas G ′ temperature can be raised to 850 ° C. or higher, and ammonia contained in the sludge S can be removed before combustion.

As a result, this step-type incinerator 1 does not require a sludge dryer for drying the sludge S or a steam supply system to the sludge dryer as in the conventional step-type incinerator. It is possible to burn waste and fuel with a high water content without providing expensive equipment, and an installation space for a sludge dryer or the like is not required, and excess steam is increased.
In addition, since this stair-type incinerator 1 can raise the combustion gas G ′ temperature to 850 ° C. or higher by drawing steam from above the dry stoker 9a, the auxiliary combustion by the auxiliary auxiliary burner 18 becomes unnecessary, and the consumption of auxiliary fuel is eliminated. The amount can be reduced and the running cost can be reduced.
Furthermore, this step-type incinerator 1 can raise the temperature of the combustion gas G ′ in the furnace to 850 ° C. or more and can remove ammonia contained in the sludge S before combustion. Generation of nitrous oxide (N ₂ O), which is a gas, and NOx, which is an acidic gas, is reduced, and the deodorizing effect is enhanced.
In addition, since the stepped incinerator 1 has the radiation plate 23 disposed above the drying stoker 9a, the sludge S on the drying stoker 9a can be reliably and satisfactorily dried by radiant heat, and The carrier gas G ″, the vapor H ₁ and the ammonia gas above the dry stoker 9a can be prevented from flowing toward the secondary combustion chamber 13, and the vapor and the ammonia gas can be satisfactorily extracted.

FIG. 3 shows an incineration plant using the stepped incinerator 1 according to the first embodiment of the present invention, which includes the stepped incinerator 1, the boiler 2, the dust collector 4, the gas cleaning tower 5, It consists of an induction fan 6 and a chimney 7.
In addition, the same reference number is attached | subjected to the same member and site | part as the stair-type incinerator 1 and incineration plant shown in FIG. 1, and the detailed description is abbreviate | omitted.

As shown in FIG. 3, the stepped incinerator 1 includes a stair sliding type stalker 9 comprising a furnace body 8, a dry stalker 9a and a combustion stalker 9b, a hopper 10 below the stalker, a feed feeder 11, a primary combustion chamber 12, Secondary combustion chamber 13, combustion air fan 14, primary combustion air supply duct 15, air heater 17, air heater 17b, auxiliary burner 18, ash discharge conveyor 19, secondary combustion air supply passage 24, secondary combustion air fan 25, the washing tower 26 and the radiation plate 23 are supplied with the primary combustion air heated by the air heater 17 under the dry stoker 9a and pass through the sludge S on the dry stoker 9a and the dry stoker 9a. water sludge S evaporation of the primary combustion air flowing over the dry stoker 9a and (steam H ₁₎ pulling together ammonia gas, in washing tower 26 primary combustion air After removing condensed steam and ammonia gas, in which then supplied to the secondary combustion chamber 13 was heated in the air heater 17b the primary combustion air as secondary combustion air.

The secondary combustion air supply path 24 includes a trumpet-shaped extraction port 24a formed in the furnace wall above the dry stoker 9a, a plurality of blow-in ports 24b formed in the furnace wall of the secondary combustion chamber 13, and an extraction port. The secondary combustion air supply duct 24c that connects the air outlet 24a and the inlet 24b in communication with each other, and the air heater 17b and the secondary combustion air fan 25 that are interposed in the secondary combustion air supply duct 24c. The primary combustion air that has passed through the sludge S on the dry stoker 9a is extracted by the fan 25 from the extraction port 24a above the dry stoker 9a together with the moisture (steam H ₁ ) and ammonia gas in the sludge S, and the secondary combustion air is supplied. after removal of vapor H ₁ and ammonia gas in the primary combustion air by scrubbing tower 26 which is interposed in the road 24, the primary combustion is heated by the air heater 17b Care only so that the Fukikomeru from blowing port 24a as secondary combustion air to the secondary combustion chamber 13.

  Further, the cleaning tower 26 is provided at a position upstream of the secondary combustion air fan 25 in the secondary combustion air supply passage 24, and injects a cleaning liquid such as water to vapor and ammonia in the primary combustion air. The gas is condensed and removed.

This step-type incinerator 1 has a cleaning tower 26 provided in the secondary combustion air supply path 24 by extracting steam and ammonia gas generated on the dry stoker 9 a by the secondary combustion air supply path 24 together with the primary combustion air. Is used to remove steam and ammonia gas from the primary combustion air and supply only the primary combustion air as the secondary combustion air to the secondary combustion chamber 13, so that the combustion gas G temperature in the furnace is increased to 850 ° C. or higher. While being able to raise, the ammonia contained in the sludge S can be removed before combustion, and there can exist the same effect as the step-type incinerator 1 shown in FIG.
In particular, the stair-type incinerator 1 is configured to condense and remove moisture (vapor) and ammonia gas evaporated by drying the sludge S in the cleaning tower 26 provided in the secondary combustion air supply path 24. The capacity of the gas cleaning tower 5 installed in the exhaust gas discharge line can be reduced. Moreover, running cost can be reduced.

FIG. 4 shows an incineration plant using the stepped incinerator 1 according to the second embodiment of the present invention, which includes the stepped incinerator 1, the boiler 2, the dust collector 4, the gas cleaning tower 5, It consists of an induction fan 6 and a chimney 7.
In addition, the same reference number is attached | subjected to the same member and site | part as the stair-type incinerator 1 and incineration plant shown in FIG. 1, and the detailed description is abbreviate | omitted.

As shown in FIG. 4, the stepped incinerator 1 includes a stepped slide type stoker 9 comprising a furnace body 8, a dry stoker 9 a and a combustion stoker 9 b, a stoker lower hopper 10, a feed feeder 11, a primary combustion chamber 12, and a second combustion chamber 12. Secondary combustion chamber 13, combustion air fan 14, primary combustion air supply duct 15, air heater 17, gas heater 17c, auxiliary burner 18, ash discharge conveyor 19, exhaust gas supply path 20, dry carrier fan 21, exhaust gas circulation path 27, an exhaust gas circulation fan 28, a cleaning tower 29, and a radiation plate 23. A part of the exhaust gas G 'that has been recovered by heat recovery from the exhaust gas discharge line of the step-type incinerator 1 is drawn out, and this is used as a dry stoker. 9a, the grate of the dry stoker 9a and the sludge S on the dry stoker 9a are allowed to pass through, and the carrier gas G ″ passing through the sludge S is evaporated. Sludge water in the S (steam H ₁₎ and pulling with ammonia gas from above the drying stoker 9a, after removing condensed steam H ₁ and ammonia gas in the carrier gas G "in our wash tower 29, the gas heater 17c The carrier gas G ″ is supplied to the secondary combustion chamber 13 as a recirculation gas after being heated at.

  The exhaust gas supply path 20 has one end connected to the gas duct 3 connecting the dust collector 4 and the gas cleaning tower 5, and the other end connected to the hopper 10 under the stoker disposed at the lower position of the dry stoker 9a. Part of the exhaust gas G ′ having a temperature of 200 ° C. to 250 ° C. from the exhaust gas discharge line by the suction force of the dry carrier fan 21. The exhaust gas G ′ thus extracted is supplied as carrier gas G ″ to the dry stoker 9a.

Further, the exhaust gas circulation path 27 includes a trumpet-shaped extraction port 27a formed on the furnace wall above the dry stoker 9a, a plurality of injection ports 27b formed on the furnace wall of the secondary combustion chamber 13, and an extraction port 27a. The exhaust gas circulation duct 27c that connects the opening 27b in a continuous manner and the exhaust gas circulation fan 28 interposed in the exhaust gas circulation duct 27c, the carrier gas G ″ that has passed through the sludge S on the dry stoker 9a by the exhaust gas circulation fan 28. with evaporated water in the sludge S (steam H ₁₎ and ammonia gas withdrawal from the top of the withdrawal opening 27a of the drying stoker 9a, steam H ₁ and a carrier gas G "in the wash column 29 which is interposed in an exhaust gas circulation path 27 After removing the ammonia gas, it is heated by the gas heater 17c and only the carrier gas G ″ is blown as a recirculation gas. It is adapted to supply to the secondary combustion chamber 13 from 27b.

Further, the cleaning tower 29 is provided at a position upstream of the exhaust gas circulation fan 28 in the exhaust gas circulation path 27 and injects a cleaning liquid such as water to remove the vapor H ₁ and ammonia gas in the carrier gas G ″. It is designed to be condensed and removed.

This stepped incinerator 1 draws out steam H ₁ and ammonia gas generated on the dry stoker 9 a by the exhaust gas circulation path 27 together with the carrier gas G ″, and exhaust gas G by the cleaning tower 29 interposed in the exhaust gas circulation path 27. 'Is removed, and only the carrier gas G "is supplied as the recirculation gas to the secondary combustion chamber 13, so that the temperature of the combustion gas G in the furnace can be raised to 850 ° C or higher. In addition, the ammonia contained in the sludge S can be removed before combustion, and the same effects as the step-type incinerator 1 shown in FIG. 1 can be achieved.
In particular, since the stair-type incinerator 1 condenses and removes moisture (vapor) and ammonia gas evaporated by drying the sludge S in the cleaning tower 29, the gas cleaning tower 5 installed in the exhaust gas discharge line. The capacity of can be reduced.
In addition, the stepped incinerator 1 supplies the secondary combustion chamber 13 with the carrier gas G ″ extracted from above the dry stoker 9a as the recirculation gas, so that NOx can be reduced.

  1 is a stepped incinerator, 9 is a stoker, 9a is a dry stoker, 9b is a combustion stoker, 12 is a primary combustion chamber, 13 is a secondary combustion chamber, 20 is an exhaust gas supply path, 22 is an exhaust gas return path, and 23 is a radiation plate , 24 is a secondary combustion air supply path, 26 is a cleaning tower, 27 is an exhaust gas circulation path, and 29 is a cleaning tower.

Claims (3)

Equipped with a stoker consisting of a dry stoker and a combustion stoker. The primary combustion air is supplied from the bottom of the stoker to the primary combustion chamber above the stoker to cause primary combustion of waste and fuel with high water content supplied on the stoker. In a stepped incinerator where secondary combustion of unburned gas and unburned material is performed in a secondary combustion chamber above the chamber, the stepped incinerator is supplied under the dry stoker and discarded on the dry stoker. A secondary combustion air supply passage that draws the primary combustion air that has passed through materials and fuel together with steam and ammonia gas generated on the dry stoker and supplies only the primary combustion air as secondary combustion air to the secondary combustion chamber; A stair-type incinerator comprising a cleaning tower that is provided in a combustion air supply path and that condenses and removes steam and ammonia gas extracted together with primary combustion air . Equipped with a stoker consisting of a dry stoker and a combustion stoker. The primary combustion air is supplied from the bottom of the stoker to the primary combustion chamber above the stoker to cause primary combustion of waste and fuel with high water content supplied on the stoker. In a stepped incinerator in which unburned gas and unburned substances are secondarily burned in a secondary combustion chamber above the chamber, the stepped incinerator is configured to discharge exhaust gas from an exhaust gas discharge line of the stepped incinerator. Exhaust gas supply path that pulls out the part and supplies it to the dry stoker, and exhaust gas that has passed through the waste and fuel on the dry stoker is extracted with the vapor and ammonia gas generated on the dry stoker, and only the exhaust gas is used as a recirculation gas as a secondary gas. An exhaust gas recirculation path that supplies the combustion chamber, and a cleaning tower that is provided in the exhaust gas recirculation path and that condenses and removes the steam and ammonia gas extracted along with the exhaust gas. It stepped incinerator and said that you are. In the upper position of the dry stoker, the exhaust gas passing through the waste and fuel on the dry stoker or the primary combustion air and the steam and ammonia gas generated on the dry stoker are prevented from flowing to the secondary combustion chamber side, and the dry stoker The step-type incinerator according to claim 1 or 2 , further comprising a radiating plate for radiating heat to the waste or fuel above .

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