JPH0776608B2 - Fluidized bed high water content incinerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a fluidized bed for burning and incinerating highly water-containing wastes (residues) such as beer barley meal, coffee bean meal and sludge containing a large amount of water. Type high water content incinerator.

[Conventional technology]

Conventionally, in a fluidized bed type incinerator that burns highly water-containing waste in a fluidized bed and incinerates it, the air for combustion and fluidization is supplied to the combustion chamber through a gas dispersion plate at the lowest stage of the incinerator. For controlling the fluidized bed temperature of the combustion chamber to a high temperature of the target value (constant value) by installing an auxiliary combustion burner in the air chamber for instantaneously evaporating a large amount of water contained in the high water content waste in the fluidized bed,
Moreover, the high water content waste is stably burned and incinerated by burning the waste.

[Problems to be Solved by the Present Invention]

In this way, in a fluidized bed type high water content incinerator in which an auxiliary combustion burner is installed in the air chamber, high water content waste, especially water, is removed.
When burning high water content waste containing 80% or more,
Or even if the water content of the waste during normal operation is lower than this value, if it exceeds such a high value, the auxiliary combustion amount increases, and at the normal air amount, the gas in the air chamber is increased. Since the temperature rises too much, the amount of air must be increased and the temperature must be lowered in order to maintain the heat resistance of the air chamber.

In such a situation, operation with poor thermal efficiency is naturally required.

On the other hand, in order to deal with such a problem, there is a method in which a burner in sand is exposed in a fluidized bed (in a fluidized medium) and attached to a combustion chamber, and fuel such as heavy oil is blown into the fluidized bed. However, since there is a limit to the capacity per burner, a large number of burners are required, and the combustion is greatly affected by the temperature of the fluidized medium, which makes stable combustion difficult.

The object of the present invention is to eliminate such problems and to obtain a fluidized bed type high water content waste incinerator with good thermal efficiency.

[Means for Solving the Problems]

In order to achieve the above object, the fluidized bed high water content waste incinerator of the present invention has an air chamber provided with a burner for auxiliary combustion in the lower stage, and is provided in the upper stage of the air chamber via a gas dispersion plate. It has a primary combustion chamber for combusting a high water content waste supplied to a freeboard in a primary combustion fluidized bed formed by fluidizing with high temperature air supplied from the air chamber, and a gas downstream of the primary combustion chamber. A fluidized bed type high water content waste incinerator having a secondary combustion chamber having a secondary combustion fluidized bed on the side, and an exhaust gas outlet on the gas downstream side of the secondary combustion chamber, the primary combustion chamber A plurality of high water content waste spray nozzles are attached to the furnace wall facing the freeboard of the primary combustion chamber at intervals laterally,
An auxiliary burner is provided on the furnace wall of the primary combustion chamber at a lower position close to the high water content waste spray nozzle and between the high water content waste spray nozzles adjacent to each other in the lateral direction. This is a structure in which a plurality of freeboards are attached at intervals in the lateral direction. [Operation] In the freeboard (combustion chamber space) of the primary combustion chamber, by performing combustion with a flame by an auxiliary burner, the gas temperature of the freeboard is raised and the radiant heat (radiant heat) of the gas is used. Raise the temperature of the primary combustion fluidized bed in the primary combustion chamber. This makes it possible to reduce the amount of auxiliary combustion of the auxiliary combustion burner in the air chamber, so that unnecessary cooling air is not used. In this case, the temperature of the freeboard is equalized as much as possible because a plurality of auxiliary burners are attached at intervals in the lateral direction.
The temperature rise of the primary combustion fluidized bed due to the radiant heat of the gas is also performed over the entire fluidized bed as much as possible. For these reasons, the thermal efficiency is improved and the boiler efficiency is improved.

Further, by raising the temperature of the freeboard in the primary combustion chamber, high water-containing waste containing, for example, 80% of water is injected and supplied from the spray nozzle to the freeboard to reach the primary combustion fluidized bed. A predetermined amount of water in the waste is evaporated and dried, the drying / combustion load in the primary combustion fluidized bed is reduced, and the combustion efficiency in the primary combustion fluidized bed is also improved. That is, the auxiliary burner is located at a lower position in the vicinity of and between the plurality of high-water-content waste spray nozzles that are adjacent to each other in the lateral direction of the furnace, and the auxiliary burners are spaced apart in the lateral direction of the furnace. Since the high water content wastes supplied and dispersed from each spray nozzle reach the primary combustion fluidized bed, they are spread out from the auxiliary burner that is ejected from the lower side of the high water content wastes. Directly with the flame, or
The high-temperature combustion gas produced by the flame is efficiently contacted, and the moisture content of the high-water content waste is efficiently evaporated.

Further, since a plurality of spray nozzles are provided in the lateral direction of the furnace, the high water content residue is uniformly supplied to the primary combustion fluidized bed, so that efficient fluidized bed combustion is performed.

In addition, by raising the temperature of the gas of the freeboard, it contributes to the combustion of unburned carbon and other unburned carbon discharged from the primary combustion fluidized bed, which also improves the combustion efficiency.

In particular, the present invention has a secondary combustion chamber on the downstream side of the primary combustion chamber, that a part of the unburned substances such as unburned carbon is burned in the freeboard of the primary combustion chamber, and, By raising the temperature of the gas passing through the freeboard, it is possible to raise the temperature of the secondary combustion fluidized bed in the secondary combustion chamber, which allows the secondary combustion chamber to remove the remaining unburned components in the primary combustion chamber. It is possible to capture and completely burn it, and it is extremely effective in completely burning high water content waste by two-stage combustion to improve combustion efficiency and thermal efficiency.

〔Example〕

1 and 2 are diagrams for explaining an embodiment of the present invention. FIG. 1 is a schematic vertical cross-sectional view of a fluidized bed high water content waste incinerator, and FIG. 2 is an arrow II in FIG. It is a main part side view.

In FIG. 1, a fluidized bed high water content waste incinerator 1 has an overall structure in which an air chamber 2 is located at the lowest stage, and a primary combustion chamber 5 is located above the air chamber 2 via a gas dispersion plate 4. A secondary combustion chamber 11 is arranged on the upper stage thereof with another gas dispersion plate 10 interposed therebetween. In the air chamber 2, an auxiliary combustion burner 3 having a combustion air intake 3a is attached to the furnace wall. A large number of gas dispersion pipes 4a are attached to the lower gas dispersion plate 4, and the high temperature air in the air chamber 2 is supplied to the gas dispersion pipes 4a.
It is supplied into the primary combustion chamber 5 through 4a. Primary combustion chamber 5
In the upper part of the gas dispersion plate 4, a fluidized medium 6a made of silica sand or the like having a particle size of 1 mm or less is fluidized from the air chamber 4 by the hot air blown up from the gas dispersion pipe 4a of the gas dispersion plate 4 and is fluidized to the primary A combustion fluidized bed 6 is formed. The upper part of this primary combustion fluidized bed 6 is a freeboard (space part) 7
An auxiliary burner 8 is attached to the furnace wall so as to face the freeboard 7. A combustion air intake 8a is attached to the auxiliary burner 8. And the auxiliary burner 8
A spray nozzle (also referred to as a raw material supply / dispersion nozzle) 9 for beer (wheat) meal (hereinafter also referred to as a raw material) as a highly water-containing waste is installed on the furnace wall above.
The raw material spray nozzle 9 disperses and supplies the high-water-content waste, which is a raw material supplied from the central portion, in the mixing chamber at the front end while mixing with compressed air or steam supplied from the periphery thereof. In addition, as shown in FIG. 2, a plurality of auxiliary burners 8 and raw material spray nozzles 9 are respectively installed facing the furnace wall, and the auxiliary burners 8 are located near the raw material spray nozzles 9 at the lower position. Located between and installed.

A secondary combustion chamber 11 is located above the primary combustion chamber 5 via a gas dispersion plate 10. The gas dispersion pipe 10a of the gas dispersion plate 10 is formed of a straight pipe so that the combustion ash of the waste in the primary combustion chamber 5 and the like can go straight when passing with the exhaust gas to prevent the adhesion as much as possible. There is. Gas dispersion plate 10
In the upper part of the secondary combustion fluidized bed 12 formed by a fluidized medium 12a made of silica sand or the like having a particle size of 1 mm or less, as in the primary combustion fluidized bed 6, is fluidized and formed by the combustion exhaust gas from the primary combustion chamber 5. It An exhaust gas discharge port is provided above the secondary combustion chamber 11.
13 is installed.

Fluidized bed high water content waste incinerator 1 constructed in this way
The operation of will be described.

In the air chamber 2, combustion air is introduced from the intake port 3a, and fuel such as heavy oil is supplied to the auxiliary combustion burner 3 to operate the auxiliary combustion burner 3. As a result, a high temperature gas of 800 to 1000 ° C. is blown up from the gas dispersion plate 4 and the primary combustion chamber 5
To form a primary combustion fluidized bed 6. The temperature of the primary combustion fluidized bed 6 is maintained at, for example, 750 ° C. by controlling the combustion amount of the auxiliary combustion burner 3.

On the other hand, in the primary combustion chamber 5, fuel such as heavy oil is combusted from a plurality of auxiliary burners 8 provided on the furnace wall by combustion air taken in through the intake port 8a, and a flame as shown by symbol A in FIG. Are discharged toward the freeboard 7, which raises the temperature of the freeboard 7 and raises the temperature of the fluidized bed of the combustion chamber by that amount due to the radiant power of the gas. In this case, when the temperature of the primary combustion fluidized bed 6 is 750 ° C, the temperature of the freeboard 7 is 800 to 900 ° C. Further, since the plurality of auxiliary burners 8 are arranged in the width direction, the temperature of the freeboard 7 is made as uniform as possible. Then, beer lees pass through the freeboard 7 as a high-water content waste containing 80% of water from a plurality of raw material spray nozzles 9 arranged on the furnace wall in close proximity to the upper part of the furnace, and are denoted by B in FIG. Is drawn and distributed evenly to the surface of the primary combustion fluidized bed 6 and is supplied. While the beer lees reach the primary combustion fluidized bed 6, the auxiliary burner 8 burns to evaporate a predetermined amount of water, and the load on the primary combustion fluidized bed 6 is reduced. That is, the auxiliary burner 8 is located at a lower position in the vicinity of a plurality of raw material spray nozzles 9 that are adjacent to each other in the horizontal direction of the furnace 1 and between the raw material spray nozzles 9, and a plurality of auxiliary burners 8 are provided in the horizontal direction of the furnace 1. Since the beer lees supplied and dispersed from the respective spray nozzles 9 reach the primary combustion fluidized bed 6 by being installed at intervals, the flame of the auxiliary burner 8 is jetted out from the lower side of the beer lees. Directly or directly in contact with the high temperature combustion gas generated by the flame to efficiently evaporate the water content of the beer lees. Then, the beer lees contact with the fluidized medium 6a (sand) that is heated to a high temperature and forms a fluidized bed in the primary combustion fluidized bed 6, whereby the water content is instantly evaporated. The dewatered beer lees are easily burned while being stirred by the fluidized bed sand. An example of analysis of this beer lees is as follows: Higher calorific value 4850 Kcal / dry k
g, the elemental components are carbon 48.86%, hydrogen 6.91%, oxygen 3
7.14%, nitrogen 3.23%, ash 3.28%, other 0.58%. About 70 to 80% of the beer lees are burned in the primary combustion fluidized bed 6, and the remaining about 30 to 20% of unburned carbon (unburned carbon) is accompanied by the combustion gas to form freeboard 7 together with ash (ash). It passes through the gas dispersion plate 10 and is introduced into the secondary combustion chamber 11. At this time, a part of the unburned component is burned in the high temperature atmosphere due to the combustion of the auxiliary burner 8 while passing through the freeboard 7. In the secondary combustion chamber 11, the secondary combustion fluidized bed 12 is formed, and the remaining unburned components finally introduced therein are combusted and completely combusted. The temperature of the secondary combustion fluidized bed 12 can be raised by such combustion of the unburned components on the freeboard 7, and the characteristics of the two-stage combustion can be further enhanced.

Combustion exhaust gas at 800 to 900 ° C. is discharged from the secondary combustion chamber 11 from the exhaust gas discharge port 13 and guided to a waste heat boiler (not shown), where the heat amount is recovered and converted to steam.

However, in the present invention, since the auxiliary burner 8 is operated in the primary combustion chamber 5 as described above, even if the high water content waste having 80% of water content is burned and incinerated, the freeboard Since the temperature of the primary combustion fluidized bed 6 is raised by raising the gas temperature in 7 and utilizing the radiant power of the gas, it is not necessary to increase the auxiliary combustion amount of the auxiliary combustion burner 3 in the air chamber 2 It is not necessary to use air (excess air). Therefore, the boiler efficiency can be increased. Further, even in the case of a high water content waste having a relatively small water content, even when the water content is extremely increased, it is possible to deal with the same problem without increasing the auxiliary combustion amount of the auxiliary combustion burner 3.

Further, in the present invention, the combustion chamber is divided into the primary combustion chamber 5 and the secondary combustion chamber 11
Since it is configured to perform two-stage combustion, the unburned component (unburned carbon) can be completely captured and completely burned in the secondary combustion chamber 11, so that the combustion efficiency is good and 400 to 450
High hearth load of kg / m ² · hr can be obtained. Further, as compared with an incinerator having a fluidized bed with only one stage, the cylinder speed can be made higher, the fluidized bed area can be made smaller, the size of the furnace can be made smaller, and it can be made compact.

Although the raw material spray nozzle 9 is mounted in a horizontal state in FIG. 1, it may be mounted in a state in which the tip end side is tilted downward depending on the raw material.

〔The invention's effect〕

As is apparent from the above description, in the present invention, by performing combustion with a flame by the auxiliary burner in the freeboard of the primary combustion chamber, the gas temperature of the freeboard is raised and the radiant heat of the gas is used to perform the primary combustion. The temperature of the primary combustion fluidized bed of the chamber can be increased. As a result, the amount of auxiliary combustion of the auxiliary combustion burner in the air chamber can be reduced, and unnecessary cooling air is not used. in this case,
Since a plurality of auxiliary burners were installed laterally at intervals, the temperature of the freeboard was made as uniform as possible, and the temperature of the primary combustion fluidized bed was raised as much as possible by the radiant heat of the gas, It is carried out throughout the fluidized bed. Therefore, the thermal efficiency can be improved and the boiler efficiency can be improved.

Further, by raising the temperature of the freeboard in the primary combustion chamber, the high water-containing waste containing a large amount of water is introduced and supplied from the spray nozzle to the freeboard to reach the primary combustion fluidized bed. Since a predetermined amount of water in the waste can be evaporated and dried, the drying / combustion load in the primary combustion fluidized bed can be reduced and the combustion efficiency in the primary combustion fluidized bed can be improved. That is, the auxiliary burner is located at a lower position in the vicinity of and between a plurality of high-water-content waste spray nozzles that are adjacent to each other in the lateral direction of the furnace, and a plurality of auxiliary burners are arranged at intervals in the lateral direction of the furnace. By installing it, the high water content waste supplied and dispersed from each spray nozzle is ejected with a spread from the auxiliary burner ejected from the lower side of the high water content waste while it reaches the primary combustion fluidized bed. The high-temperature waste gas can be efficiently contacted directly or with the high-temperature combustion gas generated by the flame, and the evaporation of water in the high-water content waste can be efficiently performed.

And since a plurality of spray nozzles are provided in the lateral direction of the furnace,
The high water content residue can be evenly supplied to the primary combustion fluidized bed for efficient fluidized bed combustion.

Further, since the temperature of the freeboard gas is raised, it contributes to the combustion of unburned carbon and other unburned carbon discharged from the primary combustion fluidized bed, and the combustion efficiency can be improved from this point as well.

And, in the present invention, the secondary combustion chamber is provided on the downstream side of the primary combustion chamber, and some unburned materials such as unburned carbon are burned in the freeboard of the primary combustion chamber, and, By raising the temperature of the gas passing through the freeboard, it is possible to raise the temperature of the secondary combustion fluidized bed in the secondary combustion chamber, which allows the secondary combustion chamber to remove the remaining unburned components in the primary combustion chamber. It can be captured and completely burned, and the high-waste waste can be completely burned by the two-stage combustion to improve the combustion efficiency. For this reason, a high hearth load can be obtained, the fluidized bed area can be reduced, and the size of the furnace can be made small and compact.

As described above, according to the present invention, it is possible to obtain a fluidized bed type high water content waste incinerator having extremely high thermal efficiency.

[Brief description of drawings]

1 and 2 are diagrams for explaining an embodiment of the present invention. FIG. 1 is a schematic vertical cross-sectional view of a fluidized bed high water content waste incinerator, and FIG. 2 is an arrow II in FIG. It is a main part side view. 1 ... Fluidized bed type high water content incinerator, 2 ... Air chamber, 3
…… Auxiliary combustion burner, 4, 10 …… Gas dispersion plate, 5 …… Primary combustion chamber, 6 …… Primary combustion fluidized bed, 7 …… Freeboard,
8 ... Auxiliary burner, 9 ... Raw material spray nozzle, 11 ... Secondary combustion chamber, 12 ... Secondary combustion fluidized bed, 13 ... Exhaust gas discharge port.

Claims (1)

[Claims] 1. An air chamber provided with a burner for auxiliary combustion in a lower stage, and a high water content waste supplied to a freeboard provided in a upper stage of the air chamber through a gas dispersion plate is supplied from the air chamber. Having a primary combustion chamber that is combusted in a primary combustion fluidized bed formed by being fluidized with high-temperature air, and having a secondary combustion chamber having a secondary combustion fluidized bed on the gas downstream side of the primary combustion chamber, A fluidized bed type high water content waste incinerator having an exhaust gas outlet on the gas downstream side of the secondary combustion chamber, wherein the furnace wall of the primary combustion chamber faces a freeboard of the primary combustion chamber and has a high water content. Install a plurality of waste spray nozzles at intervals in the lateral direction,
An auxiliary burner is provided on the furnace wall of the primary combustion chamber at a lower position close to the high water content waste spray nozzle and between the high water content waste spray nozzles adjacent to each other in the lateral direction. Fluidized bed type high water content incinerator with a plurality of horizontally spaced intervals facing the freeboard.