JP2001276565A - Method and column for quenching combustion exhaust gas of industrial waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the internal erosion generated in a quenching column for quenching exhaust gas formed by incinerating industral waste. SOLUTION: Exhaust gas is introduced into the quenching column 1 as a descending flow and successively passed through the first region 2 on the inlet side of the tower, where the cooling of the exhaust gas is generated by the heat conduction with the inner wall of the quenching column 1, the second region 5, where the cooling of exhaust gas is generated by the heat conduction with the inner wall and cooling water, of the tower and the third region 4, where the exhaust gas is quenched to at least a temperature range of 800-80 deg.C by cooling water ejected from a spray nozzle 3, of the tower. The inner wall of the second region 3 is constituted of SK30 refractory.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a waste plastic,
The present invention relates to a method for quenching an exhaust gas obtained by incinerating industrial waste other than metal scrap such as waste oil, sludge, plating waste liquid, and the like, and an inner wall structure of a quenching tower. The applicant of the present invention processes about 100 tons of industrial waste daily according to the flow introduced in "Resources and Materials, Special Issue on Recycling", 1997 (113), 12, p. 1177.
In addition, a quenching tower is used to quench a specific temperature so as not to generate dioxin in exhaust gas generated in a BASF incinerator.

[0002]

2. Description of the Related Art A conventional exhaust gas quenching tower is composed of 1173K (900 ° C.) to 1273K (1
Exhaust gas of about 000 ° C) downward, water is sprayed at a flow rate of about 360 m ³ / hr in a spray area provided on the way, and rapidly cooled from 973K (700 ° C) to 343K (70 ° C) or less. Is suppressed. The cooled exhaust gas is sent to the scrubber from the bottom of the tower to remove dust,
On the other hand, the cooling water is sent to a wastewater treatment facility for neutralization. The spray wall on the inner wall of the conventional exhaust gas quenching tower used a carbon brick, and a fire-resistant caster in which alumina cement was mixed with a fire-resistant aggregate was used in a region where spray water was not applied. In addition, it has been reported that refractories containing Cr ₂ O ₃ show excellent performance in incinerators (Taikabutsu 51 [4] 237-
246 (1999)), and even general-purpose refractory casters have not hindered actual operation.

[0003]

The problem encountered during the actual operation of the above-mentioned exhaust gas quenching tower is that the refractory caster immediately above the spray area is weathered in about one month, and the refractory must be reconstructed. Industrial waste disposal had to be interrupted. On the other hand, the refractory life of the incinerator is several months or more, and there is no problem with the refractory life of the part directly exposed to the spray water. It is considered that corrosion due to competitive action has occurred, and there was no literature that previously discussed such a phenomenon.Therefore, the present inventors conducted tests on various refractory and heat-resistant materials to stabilize the incineration operation of industrial waste. Could be realized.

[0004]

SUMMARY OF THE INVENTION The method according to the present invention is
Includes dust generated from incineration of industrial waste and
Degree 0.3-1.5%, SO_TwoConcentration 0.5-3%, H
_TwoExhaust gas with O saturation concentration is introduced downward into the quenching tower
The exhaust gas is cooled mainly by heat conduction with the inner wall of the quench tower.
In the first area on the entrance side of the tower where rejection occurs, mainly the heat of the inner wall of the tower
Secondly, cooling is caused by conduction and by the following cooling water
By area and cooling water injected from spray nozzle
At least 973K (700 ° C) to 343K (70
(° C), pass through the third region where the temperature range is rapidly cooled.
Industrial waste incineration exhaust gas quenching method, SK30 resistant
Fire or SiO_Two: 65-75% , Al_TwoO_Three: 25-
30% , Fe_TwoO_Three: SK30 refractory having a composition of 5% or less
Exhaust gas through a second zone, which is substantially composed of
Industrial waste incineration exhaust gas quenching method
Yes, and the quenching tower according to the present invention incinerates industrial waste.
Exhaust gas containing dust generated by
Cooling occurs due to heat conduction between the mouth and the inner wall of the tower
Due to the heat conduction between the first area on the inlet side of the tower and the inner wall of the tower
As a result, cooling takes place by the following cooling water,
Touch the part with SK30 refractory or SiO_Two: 65
~ 75% , Al_TwoO_Three: 25-30% , Fe_TwoO_Three: 5% or less
Consisting essentially of a SK30 refractory equivalent having the composition
And the cooling water injected from the spray nozzle
At least 973K (700 ° C) to 343K
(70 ° C.) in a third region for quenching the temperature range.
It becomes. Hereinafter, the present invention will be described in detail.

[0005] The incineration method of industrial waste according to the present invention belongs to the so-called incinerator method, and is disclosed by the present applicant in Japanese Patent Application Laid-Open No. Hei 10-18515.
The fluidized bed proposed in JP-A No. 4 may be used, but is generally not used. The generated exhaust gas is mainly CO, CO ₂ , H ₂ O, O
₂ , N ₂ , containing a small amount of organic substances, but having a concentration of 0.3-1.5% HCl as a corrosive component, and a concentration of 0.5
Containing the 3% of SO _2. Hereinafter, the first to third regions will be described with reference to FIG.

The exhaust gas flowing downward through the quenching tower 1 is mainly in the first area 2 where the cooling water does not hit at all.
Cooling is performed by heat exchange with a, and radiation cooling occurs partially. The first region 2 has a length of about 1.5 m,
Temperature drop is small, from 1173K (900 ° C) to 112
Since the temperature is up to about 3K (850 ° C.) and the problem of erosion does not occur, ordinary refractory casters can be used. In the third region 4 which falls within the range of the injection angle (α) determined by the leading end opening angle of the cooling nozzle 3, for example, α = 90 °, heat exchange between the cooling water and the exhaust gas is mainly performed, and gas-liquid transfer is performed. Other than heat is negligible. The length of this area 4 is about 3.5 m, and the nozzles 3 are vertically arranged in three stages.
Sixteen are arranged at equal intervals in the circumferential direction. The temperature drop here is at least 973K (700 ° C) to 343K
(70 ° C.) is a rapid fall, and the generation of dioxin is prevented.

In a second region 5 located between these regions 2 and 4, steam evaporated from the cooling water and β
The exhaust gas is cooled by the spray water 6 scattered in the range of about 30 °, and the exhaust gas is also cooled by heat exchange with the inner wall 1a of the tower. The length of this area 5 is about 0.8 m, and the temperature drop here is 923 K (850 ° C.) to 9 m.
It is about 73K (700 ° C). In this second area 5, the inner wall of the quenching tower 1 is severely eroded for unknown reasons. If the erosion is severe, the inside of the refractory structure collapses, and the surface is usually greatly worn in normal cases. The present inventors have conducted intensive studies and found that SK30 (including its equivalent), which is a clay brick specified in JIS2304, has unexpectedly extremely high erosion resistance. Here, the equivalent products are fire resistance, bulk specific gravity,
The compressive strength is almost the same as SK30, and SK28, 32
Does not satisfy the standard, and SiO ₂ = 65-75% , Al ₂ O ₃
= 25-30% , Fe ₂ O ₃ = 5% or less. In this area, SK30 bricks are used except for the binder and the joint material for fixing the bricks.

FIG. 2 shows the overall schematic structure of the quenching tower. The quenching tower 30 is a vertical tower having an overall height of about 5.9 m and an internal volume of 27 m ³ , and a SK30 brick 35 is lined in the second area. Nozzles 31a, 31b and 31c for injecting cooling water through a valve 32 into the tower are provided in three stages.
In addition, 16 pieces are provided in each stage, and at least 1073K
The exhaust gas is rapidly cooled in a temperature range from (800 ° C.) to 353 K (80 ° C.). Most of the HCl and SO ₂ contained in the exhaust gas are dissolved in water by the water cooling. The spray water amount from all injection nozzles is 320 to 360 m ³ / hr
It is. As a result of such cooling water injection, part of the dust and HC
The processing liquid containing l, H ₂ SO _{4 and the} like accumulates in the processing liquid reservoir 31 from the bottom outlet 30b, and this processing liquid is reused as cooling water through neutralization by adding caustic soda. On the other hand, the exhaust gas cooled to 343 K (70 ° C.) or lower by the injection water is mainly composed of steam, CO ₂ , O _2, etc., the flow rate is 400 to 450 Nm ³ / hr, and the dust amount is 0.1 to
0.2 g / Nm ³ (exhaust gas volume). Such cooling exhaust gas is discharged from an exhaust gas outlet 33 provided at the lower part of the tower. Next, the results of a test performed by the inventor on an actual machine will be described.

FIGS. 3 and 4 illustrate the situation in which various refractory materials and heat-resistant alloys were tested. The tested materials 20 were potable glass acid-resistant castables (Sour Eisen Co., Ltd., product No. 54LW, comparative example), fire-resistant and acid-resistant castables (NGK product Ez3-2700, comparative example), SK.
30 clay brick (Example), anti-firestone, acid- and alkali-resistant castable (Yotai product, AS-100, comparative example) clay-acid- and water-resistant castable (Asahi glass product,
WPC-100, Comparative Example), Hastelloy C (Comparative Example)
(Registered trademark), austenitic stainless steel (comparative example) (Nippon Yakin's product NAS64) and SUS316 (comparative example).
Is a metal plate (3t × 1000 × 1000). Of these materials, as shown in FIG.
SUS316, which is arranged in a region and fixes these
Are arranged on the surface of the L-fixing jig. These materials 2
In the case of No. 0, the front surface is suppressed by the SUS316 fixing jig 23, and the acid-resistant caster 21 (Sour Eisen Co. product No. 54LW)
Embedded inside. Reference numeral 22 denotes a connection flange between the quenching tower main body and the inlet gas path. Each material 20 after actual operation for 2 months
The following results were obtained by evaluating. The upper end face was severely worn, and some parts were missing. The lower part was good. Although selven as an aggregate remained, the fine powder portion disappeared and was worn. The surface was rough but the wear was minimal. It was heavily worn and the internal structure had collapsed. The surface was heavily worn. The surface was heavily worn. Since the bolt holding the metal plate dropped off during the test, it could not be evaluated. In about two months, it corroded to a point where it had to be called a piece of paper rather than a metal plate. Weight loss due to corrosion is about 90%. Weight loss due to corrosion was about 20%.

The test results show that SK30 has excellent performance, and that other refractories, heat-resistant steels and heat-resistant alloys are defective.

[0011]

As described above, according to the present invention, incineration of industrial waste can be carried out without interruption due to repair of the incineration waste gas quenching tower, and further, the life of the exhaust gas quenching tower is prolonged. Benefits are achieved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating first to third regions in the method of the present invention.

FIG. 2 is an overall explanatory view of a quenching tower according to one embodiment of the present invention.

FIG. 3 is a diagram illustrating the positions of various test materials in a cooling tower.

FIG. 4 is an arrangement plan view of various test materials.

[Explanation of symbols]

 1-Quenching tower 2-First area 3-Cooling nozzle 4-Third area 5-Second area

 ────────────────────────────────────────────────── ─── Continued on the front page F term (reference) 3K065 AA24 AB01 AC01 BA01 HA02 HA03 3K070 DA03 DA05 DA37 DA77 4D002 AA02 AA19 BA02 BA13 BA14 CA01 DA35 4D020 AA06 AA10 BA23 BB03 CB25 CC14 CC17

Claims (2)

[Claims] 1. Exhaust gas containing dust generated by incineration of industrial waste, having an HCl concentration of 0.3 to 1.5%, an SO ₂ concentration of 0.5 to 3%, and a H ₂ O saturation concentration. Is introduced downward into the quenching tower, and the first area on the tower inlet side where the exhaust gas is cooled mainly by heat conduction with the inner wall of the quenching tower, mainly cooled by heat conduction with the inner wall of the tower and secondarily by the following cooling water A method of quenching industrial waste incineration flue gas in which the wastewater is sequentially passed through a second region in which cooling occurs and a third region in which a temperature range of at least 973K (700 ° C) to 343K (70 ° C) is rapidly cooled by cooling water injected from a spray nozzle. SK30 refractory or SiO ₂ : 65-75% , A
l ₂ O ₃ : 25-30% , Fe ₂ O _3: SK30 refractory industrial waste incineration flue gas quenching method of the second region, characterized in that allowed to pass through the exhaust gas having an inner wall consisting essentially equivalent having a composition of 5%. 2. An inlet for introducing exhaust gas containing dust generated by incineration of industrial waste downward, a first area on a tower inlet side where cooling is mainly performed by heat conduction with an inner wall of the tower, As a result of the heat conduction with the inner wall, a part of the following cooling water cools down, and SK30 refractory or Si
O _2: 65~75% , Al ₂ O ₃ : 25-30% , Fe ₂ O ₃ :
A second region having an inner wall substantially consisting of an SK30 refractory equivalent having a composition of 5% or less and at least 973 K (700
C) to 343K (70 ° C)
And an industrial waste incineration flue gas quenching tower.