JPH11316016A - Exhaust gas dust removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce an amount of fly ash adhered to a waste heat recovering steam superheating pipe of a refuse incinerator or the like by providing one or more stages of a group of fly ash collecting members at the upstream side of a waste heat recovering steam super heater. SOLUTION: A combustion exhaust gas G2 flows into the inside of a vertical air heater 2 from a bottom portion of the air heater 2 and then flows out from a first flue 9 connected with a drum portion 18 of the air heater 2. Accordingly, the air heater 2 is provided with one or more stages of a group of fly ash collecting members 27 below heat transfer pipes 19. The group of fly ash collecting members 27 are formed by disposing a plurality of circular tubular fly ash collecting members at a constant interval within a horizontal plane which transverses the drum portion 18 of the air heater 2. In such a construction, however, the fly ash collecting members of the upper stage are disposed such that they face the heat transfer pipes 19 of the air heater 2 and the fly ash collecting members of the lower stage are disposed such that they are shifted by a half pitch in a lateral direction relative to the fly ash collecting members of the upper stage. Due to such a constitution, the fly ash are adhered to the lower surfaces of the fly ash collecting members so that an amount of fly ash contained in the exhaust gas G2 can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas dust removing apparatus for removing fly ash contained in exhaust gas.

[0002]

2. Description of the Related Art Waste incinerators and waste melting furnaces that incinerate and melt waste containing components that become incinerated ash and corrosive components, and coal-fired boilers that use coal as fuel are used for waste heat recovery. Since a large amount of ash containing a corrosive component adheres to the steam heating tube, corrosion of the metal steam heating tube is likely to occur, and the life of the steam heating tube is short.

In addition, fly ash adheres to the outside of the steam superheater, so that the recovered heat energy is reduced, making it impossible to effectively use waste heat.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and has been developed in order to solve the problem. An object of the present invention is to provide an exhaust gas dust removing device capable of reducing the amount of ash.

[0005]

According to the first aspect of the present invention, there is provided an exhaust gas dust removing apparatus comprising an elongated fly ash trapping member upstream of a waste heat recovery steam superheater for recovering waste heat of exhaust gas. Characterized in that one or more fly ash catching members arranged at a constant interval in a direction crossing the flow of air are arranged.

According to the first aspect of the present invention, the fly ash catching member group is arranged at one or more stages upstream of the steam superheater. Fly ash adheres to the front surface of the fly ash capturing member, and the amount of fly ash adhering to the heat transfer tube of the steam superheater is reduced. In the exhaust gas dust removing apparatus according to the second aspect of the present invention, the fly ash catching member group is disposed at one or more stages upstream of the heat transfer tube of the air heater.

According to the second aspect of the present invention, the fly ash catching member group is constituted by disposing the fly ash catching member group at one or more stages upstream of the heat transfer tube of the air heater. Fly ash adheres to the front surfaces of the numerous elongated fly ash capturing members, and the amount of fly ash adhering to the heat transfer tubes of the steam superheater is reduced. The exhaust gas dust remover according to the third aspect of the present invention includes a fly ash capturing member group,
One or more steps are installed in the flue.

According to the third aspect of the present invention, the fly ash catching member group is disposed at one or more stages in the flue, so that a large number of elongated fly ash catching members constituting the fly ash catching member group are provided. Fly ash adheres to the front surface of the member, and the amount of fly ash adhered to the heat transfer tube of the steam superheater is reduced. In the exhaust gas removing apparatus according to the fourth aspect of the present invention, the fly ash catching member group is arranged at one or more stages upstream of the filter of the dust collector.

According to the fourth aspect of the present invention, the fly ash catching member group is arranged at one or more stages upstream of the filter of the dust collector, so that a large number of fly ash catching member groups are formed. Fly ash adheres to the front surface of the elongated fly ash capturing member, and the amount of fly ash attached to the heat transfer tube of the steam superheater is reduced. In the exhaust gas dust removing apparatus according to the fifth aspect of the present invention, a large number of heat transfer tubes for air heating are arranged in a circle outside the heat transfer tubes for steam heating of the steam superheater.

According to the fifth aspect of the present invention, since a large number of heat transfer tubes for air heating are arranged in a circle outside the heat transfer tubes for steam heating of the steam superheater, fly ash is used for steam heating. Attached to the heat transfer tube for air heating surrounding the outside of the heat transfer tube,
The amount of fly ash adhering to the heat transfer tubes of the steam superheater is reduced.
In the exhaust gas dust removing apparatus according to the sixth aspect of the present invention, the heat transfer tube for air heating is made of metal, and the outside of the heat transfer tube for air heating is covered with a protective material made of ceramics.

According to the sixth aspect of the present invention, corrosion and wear of the metal air heat transfer tube can be prevented. According to the seventh aspect of the present invention, the surface temperature of the heat transfer tube for air heating is set to be equal to or lower than the surface temperature of the steam superheater tube. According to the seventh aspect of the invention, the amount of fly ash attached to the steam superheater and the amount of condensation can be reduced.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram of a refuse melting furnace,
The refuse a previously crushed to a predetermined size is supplied to a horizontal rotary drum type pyrolysis reactor 1 through a two-stage gate type refuse charging device not shown.

Since the inside of the thermal decomposition reactor 1 is indirectly heated by the heated air b heated by the air heater 2, the refuse a in the thermal cracking reactor 1 is thermally decomposed and carbonized gas G1 And thermal decomposition residue c. The pressure in the thermal decomposition reactor 1 is maintained at or below the atmospheric pressure by an unillustrated air blower. The pyrolysis residue c discharged from the pyrolysis reaction device 1 into the discharge device 3 is separated into a combustible component d and a non-combustible component e by a separator 4. The combustible component d is supplied to the burner 6 of the melting furnace 5 through the pipe L3.

The combustible component d supplied to the burner 6 is:
The high temperature (45) supplied from the discharge device 3 through the pipe L2
(About 0 ° C.) together with the combustion air f supplied from the blower 7 through the pipe L4 in a high temperature range of about 1300 ° C. The ash generated at this time is melted slag g and falls from the bottom outlet 8 of the melting furnace 5 into a water tank (not shown) to be cooled and solidified. When the ash is melted, ash h collected by the air heater 2, the first flue 9, the dust collector 10, the second flue 11, etc. is also supplied,
Is melted.

The high temperature (about 1250 ° C.) exhaust gas G 2 discharged from the melting furnace 5 through the passage 12 is supplied to the air heater 2.
And the dust is guided to the dust collector 10 through the first flue 9 and is removed.
Furthermore, the waste heat is guided to the steam superheater 13 through the second flue 11 and recovered. Thereafter, dust is removed by a dust collector (not shown), and further, harmful components are removed by an exhaust gas purifying device (not shown).

Further, each device will be specifically described. (A) Melting Furnace In the vertical melting furnace 5, the circumferential wall 16 is provided in multiple stages on the furnace wall 15, so that the furnace wall surface area increases and the ash melting rate improves. Note that a spiral groove may be provided instead of the lateral groove 16. Further, in order to increase the furnace wall surface area, a number of rods may be attached to the furnace wall 15 of the melting furnace 5 in the direction of the central axis (not shown) of the melting furnace 5. Further, a hollow spindle may be provided at the center of the melting furnace 5. If desired, bars may be provided in multiple stages and radially on the outer surface of the hollow spindle.

(B) Air heater As shown in FIG. 1, the flue gas G2 is supplied to a vertical air heater 2
After flowing into the air heater 2 from the bottom of the air heater 2
As shown in FIG. 2, the air heater 2 is provided with one or more fly ash capturing member groups 27 below the heat transfer tube 19 because the air heater 2 flows out from the first flue 9 connected to the body portion 18 of the air heater 2. (In the illustrated case, two stages).

As shown in FIG. 3, the fly ash catching member group 27 includes a plurality of tubular fly ash catching members 28 at a predetermined interval in a horizontal plane (not shown) crossing the body 18 of the air heater 2. It is formed by providing in. However, the upper fly ash catching member 28 is provided so as to face the heat transfer tube 19 of the air heater 2, and the lower fly ash catching member 28 is laterally shifted by a half pitch with respect to the upper fly ash catching member 28. It is provided shifted. For this reason, as shown in FIG. 3, fly ash adheres to the lower surface of the fly ash catching member 28, and the amount of fly ash contained in the exhaust gas G2 decreases accordingly. The adhering ash j adhering to the fly ash capturing member 28 is cleaned at the time of the periodic inspection.

The fly ash catching member 28 may be, for example, a square tube, a cylinder, a prism, a flat plate, an arc plate, or the like, in addition to a circular tube. In short, any shape can be used as long as it can catch fly ash. However,
In the case of a circular tube or a square tube, since air can be passed through the tube, it can be used as an air heating tube. Further, the fly ash capturing member 28 is preferably made of fiber reinforced ceramics having high heat resistance.

On the other hand, the heat transfer tube 19 of the air heater 2 is shown in FIG.
As shown in the figure, a metal inner tube 21 is provided inside a bottomed cylindrical outer tube 20 made of fiber reinforced ceramics and has a double structure.
Is provided. The outer tube 20 is attached to a partition plate 22, and a pipe L <b> 1 is connected to a heated air chamber 23 partitioned by the partition plate 22. On the other hand, the end plate 2 of the air heater 2
The pipe L0 is connected to the inner pipe 21 attached to the pipe 4. (C) First flue As shown in FIG. 1, one or more fly ash capturing member groups 30 are provided in the first flue 9 that connects the air heater 2 and the dust collector 10 (illustration shown). In the case of, three steps).

As shown in FIG. 5, the fly ash catching member group 30
Are vertical planes (not shown) that respectively cross the first flue 9
It is formed by providing a plurality of prismatic fly ash capturing members 31 at regular intervals. The fly ash catching members 31 located in the middle stage are the fly ash catching members 31 located in the preceding and subsequent stages.
Are shifted laterally by a half pitch. For this reason, as shown in FIG. 5, fly ash adheres to the front surface of the fly ash capturing member 31, and the amount of fly ash contained in the exhaust gas G2 decreases accordingly.

The fly ash catching member 31 may be, for example, a square tube, a cylinder, a circular tube, a flat plate, an arc plate, or the like, in addition to the prism. In short, any shape can be used as long as it can catch fly ash. However,
In the case of a circular tube or a square tube, since air can be passed through the tube, it can be used as an air heating tube. Further, the fly ash capturing member 31 is preferably made of fire-resistant bricks or fiber-reinforced ceramics having high heat resistance.

As shown in FIG. 4, the floor surface 33 of the first flue 9
Is provided with an attached ash discharge port 34. Adhered ash outlet 3
The width of 4 may be the same as the width of the fly ash catching member 31, but its length takes into account the amount of fly ash attached to the front surface of the fly ash catching member 31 and the frequency of cleaning for removing the attached ash. Design.

The attached ash discharge port 34 is normally shielded by a shutter (not shown). When removing the attached ash adhering to the front surface of the fly ash catching member 31, the shutter is opened and the first flue 9 is hammered or the first flue 9 is hammered.
The attached ash j is crushed by a stick (not shown) projecting from an opening with a shutter (not shown) provided on the ceiling of the flue 9 and dropped into the storage chamber 35 immediately below the flue.

(D) Dust Collector As shown in FIG. 1, the vertical dust collector 10 has a single-stage fly ash catching member group 38 arranged below a bottomed cylindrical filter 37 made of ceramics.

As shown in FIG. 6, the fly ash catching member group 38 is a horizontal plane (not shown) crossing the body 40 of the dust collector 10.
It is formed by providing a plurality of tubular fly ash catching members 39 therein at a predetermined interval, that is, so as to face the filter 37. For this reason, as shown in FIG. 6, fly ash adheres to the lower surface of the tubular fly ash catching member 39, and the amount of fly ash contained in the exhaust gas G2 is reduced by that amount, thereby increasing the filtration speed. The dust collector can be reduced in size, and an inexpensive dust collector can be provided. Ash ash attached to the fly ash catching member 39
Shall be cleaned during periodic inspections.

The fly ash catching member 39 may be, for example, a square tube, a cylinder, a prism, a flat plate, an arc plate, or the like, in addition to a circular tube. In short, any shape can be used as long as it can catch fly ash. However,
In the case of a circular tube or a square tube, since air can be passed through the tube, it can be used as an air heating tube. The fly ash catching member 39 is preferably made of fiber reinforced ceramics having high heat resistance.

(E) Second flue In addition, as shown in FIG. 1, a fly ash catching member group 42 is provided in the second flue 11 which connects the dust collector 10 and the steam heater 13.
There are steps. Therefore, fly ash adheres to the front surface of the fly ash catching member 43 constituting the fly ash catching member group 42, and the amount of fly ash contained in the exhaust gas G2 decreases accordingly. Note that the fly ash catching member group 42 provided in the second flue 11 has the same configuration as the fly ash catching member group 30 provided in the first flue 9, and therefore detailed description is omitted. I do.

(F) Steam superheater As shown in FIG. 1, the steam superheater 13 has a steam superheater tube group 54 in a vertical steam superheater body 45.

As shown in FIG. 7, the steam superheater 13 has a large number of heat transfer tubes 55 for air heating arranged in a circle outside the steam superheater tube group 54. The heat transfer tube 55 for air heating is shown in FIG.
As shown in FIG. 9, a double-layered structure is provided. A metal inner tube 57 is provided in a bottomed cylindrical outer tube 56 made of fiber reinforced ceramics, and air A supplied from the inner tube 57 is provided.
Is heated while passing between the inner tube 57 and the outer tube 56 as shown by the arrow. Steam superheated tube group 54
The fly ash adheres to the outer tube 56 of the air-heating heat transfer tube 55 outside the air heater, so that the amount of fly ash adhered to the metal steam superheater tube 46 is reduced.

When a metal outer tube is used, as shown in FIG. 8, the outer tube 56 has an arc-shaped protective material 58 adhered to the side facing the exhaust gas, and is used for heating the fly ash for air heating. Adhesion to the heat transfer tube is prevented, and corrosion and wear of the metal outer tube 56 are prevented. Since fly ash adheres to the protection material 58, the amount of fly ash adhered to the heat transfer tube 55 for air heating and the steam superheater tube 46 is reduced. The ash j adhering to the protection member 58 is cleaned at the time of the periodic inspection. As the adhesive, a ceramic adhesive such as polycarbosilane or polytitanocarbosilane is preferable.

By making the surface temperature of the heat transfer tube 55 for air heating equal to or lower than the surface temperature of the steam superheater tube 46, it is possible to prevent fly ash from condensing on the surface of the steam superheater tube. As shown in FIG. 1, air flows from the pipe L5 into the inner pipe 57 of the air heating heat transfer pipe 55, and the air heated through the gap between the outer pipe 55 and the inner pipe 57 passes through the pipe L6. It is blown to L4,
Used as part of the combustion air.

The flow rate of the air flowing through the inner tube 57 of the air heating tube is adjusted by the valves V1 and V2 installed in the pipe L5 to adjust the surface temperature of the outer tube of the air heating tube to the surface temperature of the steam heating tube. By doing so, it is possible to prevent fly ash from condensing on the surface of the steam superheater. The above fly ash capturing member group can be applied not only to a refuse melting furnace but also to a refuse incinerator and a coal-fired boiler.

[0034]

As described above, according to the first aspect of the present invention, the fly ash catching member group is disposed at one or more stages upstream of the steam superheater. Fly ash adheres to the front surfaces of a large number of elongated fly ash capturing members, and the amount of fly ash adhering to the heat transfer tube of the steam superheater is reduced.

According to the second aspect of the present invention, the fly ash catching member group is provided at one or more stages upstream of the heat transfer tube of the air heater. Fly ash adheres to the front surface of a large number of elongated fly ash capturing members, and the amount of fly ash adhering to the heat transfer tube of the steam superheater is reduced. Also,
According to the third aspect of the present invention, since the fly ash catching member group is disposed in one or more stages in the flue, the front surfaces of a large number of elongated fly ash catching members constituting the fly ash catching member group. Fly ash adheres to the heat transfer tube of the steam superheater, and the amount of fly ash attached to the heat transfer tube of the steam superheater decreases.

According to the fourth aspect of the present invention, the fly ash catching member group is provided at one or more stages upstream of the filter of the dust collector. Fly ash adheres to the front surfaces of the numerous elongated fly ash capturing members, and the amount of fly ash adhering to the heat transfer tubes of the steam superheater is reduced.

According to the fifth aspect of the present invention, since a large number of heat transfer tubes for air heating are arranged in a circle outside the heat transfer tubes for steam heating of the steam superheater, fly ash is generated. The amount of fly ash that adheres to the heat transfer tube for air heating surrounding the outside of the heat transfer tube for superheating and adheres to the heat transfer tube of the steam superheater is reduced.

According to the invention of claim 6, corrosion and wear of the metal heat transfer tube for air heating can be prevented. According to the seventh aspect of the present invention, the amount of fly ash attached to the steam superheater and the amount of condensation can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view of a refuse melting furnace.

FIG. 2 is a sectional view of an air heater.

FIG. 3 is a sectional view taken along the line III-III of FIG. 2;

FIG. 4 is a sectional view of a first flue.

FIG. 5 is a sectional view taken along line VV of FIG. 4;

FIG. 6 is an enlarged sectional view of a main part of the dust collector.

FIG. 7 is a cross-sectional view of a steam superheater.

FIG. 8 is a cross-sectional view of a heat transfer tube for air heating of a steam superheater.

FIG. 9 is a cross-sectional view of a heat transfer tube for air heating of a steam superheater.

[Explanation of symbols]

 G2 Exhaust gas 13 Steam superheater for waste heat recovery 27, 30, 38, 42 Fly ash capturing member group 28, 31, 39, 43 Slender fly ash capturing member

Claims (7)

[Claims] 1. A fly ash catcher comprising elongated fly ash catchers arranged at regular intervals in a direction transverse to the flow of exhaust gas upstream of a steam superheater for recovering waste heat of exhaust gas. An exhaust gas dedusting device, wherein a member group is arranged in one or more stages. 2. The exhaust gas dust removing apparatus according to claim 1, wherein the fly ash catching member group is disposed at one or more stages upstream of the heat transfer tube of the air heater. 3. The exhaust gas dust removal apparatus according to claim 1, wherein the fly ash capturing member group is disposed in one or more stages in the flue. 4. The exhaust gas dust removing apparatus according to claim 1, wherein the fly ash capturing member group is arranged at one or more stages upstream of the filter of the dust collector. 5. The exhaust gas dust removing apparatus according to claim 1, wherein a number of heat transfer tubes for air heating are arranged in a circle outside the heat transfer tubes for steam heating of the steam superheater. 6. The exhaust gas dust removing apparatus according to claim 5, wherein the heat transfer tube for air heating is made of metal, and the outside of the heat transfer tube for air heating is covered with a protective material made of ceramics. 7. The exhaust gas removing apparatus according to claim 5, wherein the surface temperature of the heat transfer tube for air heating is set to be equal to or lower than the surface temperature of the steam superheater tube.