JPH10185152A - High temperature air heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high temperature air heater in which a fear of high temperature corrosion of heat transfer pipes on an outer wall is completely eliminated and a durability is remarkably improved. SOLUTION: A high temperature air heater comprises an outer wall 36 forming a passage of high temperature exhaust gas generated by burning waste and heat transfer pipes arranged in the exhaust gas passage surround by the outer wall 36 to absorb and recover the heat of the high temperature exhaust gas to air flowing in the heat transfer pipes. The outer wall 36 is formed in a wall structure in which fireproof heat transfer pipes 35 whose inner surfaces facing the high temperature exhaust gas are made of a fireproof porous material are arranged. Air is supplied in parts 34 of the fireproof heat transfer pipes under pressure slightly higher than that of the high temperature exhaust gas passage. Further, air is discharged through the pores of porous fireproof material so as to prevent the penetration of the high temperature gas.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to industrial waste such as waste (general waste such as municipal waste from homes and offices, waste plastic, car shredder dust, waste office equipment, electronic equipment, cosmetics, etc.). Such as those containing combustible materials) in the municipal waste incinerator, industrial waste incinerator, etc., and the outer wall forming a flow path for high-temperature exhaust gas, and the exhaust gas flow path surrounded by the outer wall. The present invention relates to a high-temperature air heater that includes a heat transfer tube that has been provided, absorbs the heat of the high-temperature exhaust gas into the air flowing through the heat transfer tube, and recovers the waste heat.

[0002]

2. Description of the Related Art As one of the treatment apparatuses for waste including general waste such as municipal solid waste and combustibles such as waste plastics, the waste is put into a thermal decomposition reactor and heated in a low oxygen atmosphere to perform thermal decomposition. Then, a pyrolysis gas (dry flow gas) and a pyrolysis residue mainly composed of non-volatile components are generated, the pyrolysis gas and the pyrolysis residue are separated in an exhaust device, and the pyrolysis residue is further cooled. After that, it is supplied to a separator to separate the combustible component mainly composed of carbon and the non-combustible component composed of rubble such as metal, pottery, gravel, concrete pieces, etc., and the combustible component is pulverized. The pulverized combustible component and the above-mentioned pyrolysis gas are led to a combustion melting furnace and burned,
There is known a waste treatment apparatus in which the generated combustion ash is heated by the combustion heat generated by the combustion of the combustion melting furnace to form molten slag, and the molten slag is discharged to the outside to be cooled and solidified. Japanese Patent Publication No. Hei 6-56253). The high-temperature exhaust gas (approximately 1200 ° C.) generated in the combustion-melting furnace is recovered heat energy by a high-temperature air heater, which is a heat exchanger provided at a subsequent stage, and finally passes through a next processing step to finally obtain a clean exhaust gas. And released into the atmosphere from the chimney.

A high-temperature air heater has an outer wall forming a flow path of high-temperature exhaust gas generated by burning waste, and a heat transfer tube provided in the exhaust gas flow path surrounded by the outer wall. . Then, the heat flowing through the heat transfer tube absorbs the heat of the high-temperature exhaust gas to recover thermal energy.
A heat transfer tube is also provided on the outer wall, and the heat flowing through the heat transfer tube is absorbed by the air flowing through the tube to recover heat energy. Here, the heat transfer tube is formed of metal. Thus, the high-temperature air heater is a highly efficient energy resource system, and the recovered thermal energy is effectively used for thermal decomposition of refuse, power generation, and other facilities.

By the way, the flue gas generated from municipal solid waste incinerators and industrial waste incinerators is highly corrosive gas containing extremely corrosive corrosive substances such as chlorine and hydrogen chloride caused by waste and waste. It is. Therefore, a metal heat transfer tube (steel tube) of a high-temperature air heater exposed to a high-temperature, highly corrosive exhaust gas atmosphere is covered with a refractory material so as to have corrosion resistance to a high-temperature corrosive gas.

[0005] In the conventional high-temperature air heater 1, FIG.
As shown in the partially cutaway perspective view, a metal heat transfer tube 19 covered with a refractory material protection tube 5 made of ceramics or the like is provided in a high-temperature exhaust gas channel surrounded by an outer wall 36. Further, as shown in FIG. 7 which is a cross-sectional view of a main part in FIG. 6, a metal heat transfer tube 37 is also provided on the outer wall 36. This metal heat transfer tube 3
7, the exhaust gas passage side is covered with a refractory material 35, and the opposite side is covered with an outer casing 38 via a flexible heat insulating material 33.
It is supported by.

[0006]

However, in a high-temperature corrosive gas atmosphere, even if the metal heat transfer tube is covered with a refractory material, the high-temperature corrosive gas penetrates through the pores of the refractory material for a long time, and the steel tube is damaged. May corrode. In particular, the outer wall has a problem that it is difficult to structurally prevent the permeation of the corrosive gas. In addition, there is a problem that if the heat transfer tube on the outer wall part is partially corroded, the entire outer wall must be replaced. It is an object of the present invention to provide a high-temperature air heater in which the risk of high-temperature corrosion of a heat transfer tube on an outer wall is completely eliminated and durability is remarkably improved.

[0007]

In order to achieve the above object, a high-temperature air heater according to the present invention includes an outer wall forming a flow path for high-temperature exhaust gas generated by burning waste, and an outer wall formed by the outer wall. A heat transfer tube disposed in the exhaust gas passage, wherein the outer wall faces the high-temperature exhaust gas by absorbing heat of the high-temperature exhaust gas and recovering the heat of the high-temperature exhaust gas with air flowing through the heat transfer tube. The inner surface of the refractory heat transfer tube made of a porous refractory material is formed in a wall structure by arranging the refractory heat transfer tube, and air is flowed in the refractory heat transfer tube at a slightly higher pressure than the high temperature exhaust gas flow path. is there. Since the heat transfer tube on the outer wall is not made of metal but made of a refractory material such as silicon carbide, the danger of corrosion caused by the high-temperature exhaust gas is completely eliminated, and the durability is significantly improved. I do.
Further, in the case of a metal heat transfer tube, the temperature of
Although it was difficult to raise the temperature to 0 ° C. or higher, there is no problem if the temperature is 1000 ° C. or higher in the refractory heat transfer tube according to the present invention. In addition, since the air is caused to flow in the refractory heat transfer tube at a slightly higher pressure than the high-temperature exhaust gas passage, it is possible to prevent the high-temperature exhaust gas from penetrating from the outside to the inside of the refractory heat transfer tube and entering. Further, each of the refractory heat transfer tubes is characterized in that air is discharged through pores of the porous refractory material so as to prevent penetration of high-temperature gas. This can more reliably prevent the high-temperature exhaust gas from entering the refractory heat transfer tube, so that the air flowing through the refractory heat transfer tube and collecting the heat energy is not polluted. Therefore, there is no need to worry about whether the air is contaminated by corrosive gas at the place where the air is used. Further, the refractory heat transfer tube is supported by an outer casing via a flexible heat insulating material. This makes it structurally strong. Also,
The refractory heat transfer tube has a trapezoidal cross section.
This facilitates forming the wall structure by arranging the refractory heat transfer tubes.

The present invention also provides a pyrolysis reactor which pyrolyzes waste with a heating medium to generate a pyrolysis gas and a pyrolysis residue mainly composed of non-volatile components, and a pyrolysis reactor produced by the pyrolysis reactor. A discharge device for separating and discharging the pyrolysis gas and the pyrolysis residue, a separation device for separating the pyrolysis residue discharged from the discharge device into a combustible component and a non-combustible component, In a waste treatment apparatus including a combustion melting furnace for transferring and burning the pyrolysis gas and the combustible component, and a high-temperature air heater for absorbing and recovering the heat of the high-temperature exhaust gas generated in the combustion melting furnace by air, The high-temperature air heater uses any one of the high-temperature air heaters. Thereby, while having each said operation | movement, the processing efficiency of a waste disposal apparatus improves.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1 and FIG. 2, which is a cross-sectional view taken along the line II-II of FIG.
Reference numeral 6 denotes a wall structure in which refractory heat transfer tubes 35 whose inner surface facing the high-temperature exhaust gas 20 is made of a porous refractory material are arranged. Thus, in the present invention, the refractory heat transfer tube 35 is made of a non-metallic refractory material such as a so-called brick, not a metal, unlike the conventional one. Specifically, the refractory heat transfer tube 35
Examples of the material include silicon carbide, alumina, chromia and the like. Furthermore, in this example, the refractory heat transfer tubes 35 having a trapezoidal cross section are firmly connected to each other to form a wall structure. The thickness of the refractory heat transfer tube 35 is determined in terms of heat transfer efficiency and tube strength, but is usually about 30 to 50 mm. Further, the refractory heat transfer tube 35 is firmly supported by an outer casing 38 via a flexible heat insulating material 33.

The inside 34 of the refractory heat transfer tube 35 is configured so that air flows at a slightly higher pressure than the high-temperature exhaust gas passage, so that the high-temperature exhaust gas does not penetrate from the outside of the tube 35 into the inside. ing. Normally, the refractory heat transfer tube 35 passes through the inside of the tube through pores (not shown) of a porous refractory material so as to prevent the high-temperature exhaust gas from penetrating.
The pressure is set so as to slightly discharge the heated air to the outside of the tube 35. As a result, the high-temperature exhaust gas does not enter the inside of the refractory heat transfer tube 34, so that the air that flows through the inside of the refractory heat transfer tube 34 and recovers the thermal energy is not polluted.

FIG. 3 is an enlarged view of the refractory heat transfer tube 35,
(A) is a horizontal sectional view, (B) is a longitudinal sectional view. The refractory heat transfer tube 35 can be easily constructed by fitting a fitting concave portion 39 and a fitting convex portion 40 formed at both upper and lower ends of each unit. FIG. 4 relates to another embodiment, in which the unit is formed to be wide, and two portions which become the tube interior 34 are formed.

The refractory heat transfer tube 35 may have another cross-sectional shape such as a circular cross-sectional shape, and may have any shape as long as it can form a wall structure side by side. Further, the flexible heat insulating material 33 may be provided on the inner peripheral side of the wall of the refractory heat transfer tube 35.

FIG. 5 is a system diagram showing an embodiment of a waste treatment apparatus using a high-temperature air heater according to the present invention. In the waste treatment apparatus of the present embodiment, waste a such as municipal waste is crushed by, for example, a twin-screw type crusher.
Crushed to less than 0 mm square
It is thrown in. The waste a charged into the charging section 50 is supplied into the pyrolysis reactor 52 via the screw feeder 51. The drum body of the pyrolysis reactor 52 rotates. In the pyrolysis reactor 52, the waste a is a high temperature air heater 54 which is a heat exchanger disposed downstream of a combustion furnace, for example, a combustion melting furnace 53 for burning and melting the pyrolysis residue and the like.
To 300 to 600 ° C. The heated air g supplied via a heated hot air line L ₁ (heat medium) by, typically it is heated to about 450 ° C..

Further, the waste a heated by the heated air g is thermally decomposed into a pyrolysis gas G ₁ and a pyrolysis residue b mainly composed of non-volatile components. Separated. The pyrolysis gas G ₁ separated by the discharge device 55 is supplied from above the discharge device 55 to the burner 56 of the combustion melting furnace 53 via the pyrolysis gas line L ₂ .
The pyrolysis residue b discharged from the discharge device 55 is 450
Since the temperature is relatively high at about 0 ° C.,
The mixture is cooled to about 0 ° C. and supplied to a known single or combined separation device 58 of, for example, a magnetic separation type, an eddy current type, a centrifugal type, or a wind separation type, where the combustible component c (including ash ) And coarse-grained non-combustible component d, which is recovered in container 59 and reused.

Furthermore, combustible components c is the crusher 60, for example, 1mm milled below, is supplied to the burner 56 of the burning melting furnace 53 through the combustible component line L _3, from the pyrolysis gas line L ₂ supplied with pyrolysis gas G ₁ by the blower 61 is combusted in a high temperature range of about 1,300 ° C. with the supplied combustion air e from the combustion air line L _4,
The ash generated at this time is melted slag f by the heat of combustion.
And adheres to the inner wall of the combustion melting furnace 53,
It flows down the inner wall, falls from the bottom outlet 62 into the water tank 63, and is cooled and solidified.

High temperature exhaust gas G generated in the combustion melting furnace 53
₂ is the heat recovery in FIG 1 and the waste heat boiler 64 via a flue gas line L ₅ through the hot air heater 54 according to the present invention shown in FIG. 2, is dust in the dust collector 65, further After the harmful components are removed by the exhaust gas purifying device 66, the exhaust gas G ₃ is released to the atmosphere from the chimney 68 via the induction blower 67 as clean low-temperature exhaust gas G ₃ . The steam generated by the waste heat boiler 64 is used for power generation by a generator 69 having a steam turbine. Some of the clean exhaust gas G ₃ are supplied to the cooling device 57 by the cooling gas line L ₆ via a fan 70.

[0017]

According to the present invention, since the heat transfer tube on the outer wall is formed of a refractory material such as silicon carbide instead of a metallic material, the risk of corrosion caused by the high-temperature exhaust gas is completely eliminated. However, its durability is significantly improved. In addition, since the air is caused to flow in the refractory heat transfer tube at a slightly higher pressure than the high-temperature exhaust gas passage, it is possible to prevent the high-temperature exhaust gas from entering the pores from the outside to the inside of the refractory heat transfer tube. When the air is released through the pores of the porous refractory material so as to prevent the penetration of the high-temperature gas, it is possible to more reliably prevent the high-temperature exhaust gas from entering the refractory heat transfer tube. As a result, the air flowing through the refractory heat transfer tube and recovering the thermal energy is not contaminated. Therefore, there is no need to worry about whether the air is contaminated by corrosive gas at the place where the air is used.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a main part of a high-temperature air heater showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II-I of FIG.

FIG. 3 is an enlarged view of the refractory heat transfer tube, in which (A) is a horizontal sectional view and (B) is a longitudinal sectional view.

FIG. 4 is a horizontal cross-sectional view according to another embodiment of a refractory heat transfer tube.

FIG. 5 is a system diagram showing an embodiment of a waste treatment apparatus using a high-temperature air heater according to the present invention.

FIG. 6 is a perspective view showing a conventional technique.

FIG. 7 is an enlarged sectional view of a main part of the prior art of FIG. 6;

[Explanation of symbols]

 33 Flexible Heat Insulation Material 34 Inside Fire-Resistant Heat Transfer Tube 35 Fire-Resistant Heat Transfer Tube 36 Outer Wall 54 High Temperature Air Heater

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI F23G 5/44 ZAB F23G 5/44 ZABD 5/46 ZAB 5/46 ZABZ F23J 1/00 F23J 1/00 B F23M 5/00 F23M 5/00 DB

Claims (5)

[Claims] 1. An external wall forming a flow path of a high-temperature exhaust gas generated by burning waste, and a heat transfer tube disposed in the exhaust gas flow path surrounded by the outer wall. In a high-temperature air heater that absorbs and recovers the heat of the high-temperature exhaust gas into flowing air, the outer wall is formed in a wall structure by arranging refractory heat transfer tubes whose inner surface facing the high-temperature exhaust gas is made of a porous refractory material. A high-temperature air heater characterized in that air flows through the refractory heat transfer tube at a slightly higher pressure than the high-temperature exhaust gas flow path. 2. The high-temperature air heater according to claim 1, wherein each of the refractory heat transfer tubes discharges air through pores of the porous refractory material so as to prevent penetration of a high-temperature gas. . 3. The high-temperature air heater according to claim 1, wherein the refractory heat transfer tube is supported by an outer casing via a flexible heat insulating material. 4. The high-temperature air heater according to claim 1, wherein the refractory heat transfer tube has a trapezoidal cross section. 5. A pyrolysis reactor that pyrolyzes waste with a heat medium to generate a pyrolysis gas and a pyrolysis residue mainly composed of a nonvolatile component, and a pyrolysis reactor generated by the pyrolysis reactor. A discharge device for separating and discharging a gas and a pyrolysis residue, a separation device for separating the pyrolysis residue discharged from the discharge device into a combustible component and a non-combustible component, and the pyrolysis gas And a combustion and melting furnace for transferring and combusting the combustible component, and a high-temperature air heater for absorbing heat of high-temperature exhaust gas generated in the combustion and melting furnace into air and recovering the same. The heater is described in claims 1 to 4.
A waste treatment apparatus characterized by the above-mentioned.