JP2002350069A - Quencher - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quencher that is constituted to prevent the occurrence of PCDDs by quenching a high-temperature exhaust gas to a temperature lower than the synthesizing temperature of the PCDDs by making the exhaust gas to pass through a flow passage formed in a superimposed cooling environment in a short time and, in addition, contracting the volume of the gas by gradually reducing the cross-sectional area of the flow passage in steps. SOLUTION: This quencher is constituted by providing cooling pipes 5 for heat exchange through which a refrigerant is made to flow in parallel with each other in multiple stages in a quenching cylindrical body 2 through which the high-temperature gas, such as the exhaust gas, etc., is made to flow toward a leading-out opening 4 from a leading-in opening 3. The cross-sectional area of the cylindrical body 2 is gradually reduced in steps in the flowing direction of the high-temperature gas which is perpendicular to the longitudinal directions of the cooling pipes 5 provided in parallel with each other in many stages in the cylindrical body 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rapid cooling apparatus capable of completely preventing secondary synthesis of dioxins of harmful substances discharged from various incinerators and melting furnaces.

[0002]

2. Description of the Related Art Cooling systems used in combustion devices such as incinerators and melting furnaces are not only for waste treatment, but also for metal refining facilities, bleaching process of paper and pulp, cement, glass and ceramic factories, chemical raw materials. It is also used in a wide range of industrial fields such as chemical product manufacturing plants. However, dioxins harmful to the human body are resynthesized in the gas that is cooled and exhausted from these facilities and factories, and this is destroying the atmosphere and the global environment.
Global improvements are widely called for.

[0003] Various quenching devices have been developed to remove dioxins, which are air pollutants and harmful to the human body.

[0004]

However, this type of dioxin removal apparatus and method may cause decomposition of dioxins at high temperatures due to high-temperature combustion or cooling of exhaust gas discharged from a high temperature state into the atmosphere. Means for preventing the generation of synthetic dioxins are known, but all have problems that the structure is complicated, effective, and inexpensive.

That is, by the high temperature treatment of 800 ° C. or more in the combustion apparatus, the organic substances constituting the synthetic resin, such as the chlorine component and the hydrogen component, in the combustion material are completely reacted or decomposed into elemental molecules and become high-temperature exhaust gas. Exist. In this state, dioxins that are harmful to the human body are decomposed and become harmless, but when cooled and dropped to about 300 ° C., the resynthesis generation temperature of dioxins, dioxins are re-synthesized and generated again. There is an inconvenience.

In order to prevent the resynthesis of dioxins from high-temperature exhaust gas thermally decomposed at a high temperature, 1000
It has already been found that it is necessary to rapidly cool a high-temperature exhaust gas of about 800 ° C. in a decomposed state to a low temperature of 300 ° C. or less, for example, 150 ° C. or less, which is called a resynthesis temperature, in a short time of 16 seconds or less. .

The present invention has been made by paying attention to the points described above, and has been created by the present inventor in Japanese Patent Application No. 11-1052.
Another object of the present invention is to provide a rapid cooling apparatus which has an excellent cooling effect and does not cause resynthesis of dioxins and the like, in addition to the inventions of Japanese Patent Application No. 50, Japanese Patent Application No. 11-138841 and Japanese Patent Application No. 2000-112000.

[0008]

SUMMARY OF THE INVENTION The present invention has been made by paying attention to the points described above, and has been achieved by providing the following structure.

(1) A cooling pipe for heat exchange through which a multi-stage cooling medium passes is provided in a quenching cylinder through which a high-temperature gas such as exhaust gas passes from an inlet opening toward an outlet opening. A rapid cooling device characterized by gradually decreasing the cross-sectional area of a quenching cylinder according to a gas passing direction, wherein a length direction of a heat exchange cooling pipe provided in a multistage in the quenching cylinder is provided. The length is gradually reduced stepwise along the direction of introduction of the hot gas in a direction orthogonal to
A rapid cooling device characterized in that the cross-sectional area of a quenching cylinder is reduced and changed in multiple stages.

(2) The heat exchange cooling pipes provided in multiple stages in the quenching cylinder are arranged so as to be deviated in a checkered cross section so that high-temperature gas can be cooled while meandering. The rapid cooling device according to the above (1).

Here, the dioxins referred to in the present invention are polychlorinated dibenzoparadioxins (Poly-chlorina) containing 75 isomers and homologs.
ted dibenzo-p-dioxins: PCD
Ds) and 135 kinds of isomers and homologues are present in polychlorinated dibenzofuran (Poly-chlorinated)
ibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) also have 209 types of isomers and homologs, and 12 types of coplanar PCBs (Co-PCB) isomers and homologs having a co-flat structure. The body is highly toxic, and its biological effects are similar to those of PCDDs. Co-PCB is present in PCB products and, like PCDDs and PCDFs, is produced in waste incinerators to broaden the environment. Because it is contaminated, this C
It is generically called dioxins including o-PCB.

The structural formula is shown below.

[0013]

Embedded image

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

Reference numeral 1 denotes a quenching device, which is provided with a quenching cylinder 2 having a three-dimensional chamber configuration which is flat, square, preferably rectangular, and whose side surfaces are long in the vertical direction. Reference numeral 3 denotes an inlet opening (upper side in the drawing) which is opened on the upper side or the lower side of the quenching cylinder 2 and is in a decomposition state of constituent chemical molecules of dioxins generated from various furnaces, for example, at 800 ° C. or higher. High temperature exhaust gas can be introduced. Reference numeral 4 denotes a low-temperature exhaust gas after quenching treatment, which is opened at the lower side or the upper side of the quenching cylinder 2, that is, a much lower temperature of 200 ° C. or lower, which is referred to as a synthesis temperature of dioxins, for example, 30 ° C. to 50 ° C. or lower. This is a discharge opening (lower side in the figure) of the exhaust gas that can be discharged at a low temperature.

Reference numeral 5 denotes a cooling tube for heat exchange having a desired shape such as a circular or square cross section. The cooling tube is made of a metal such as stainless steel or titanium having a high heat resistance or a heat resistant ceramic. A large number are superposed and cooling air or cooling liquid is supplied from one opening end to the other opening end.

The cooling pipe 5 is provided with heat-absorbing fins (not shown) for enhancing the heat exchange effect where necessary, and a large number of the cooling pipes 5 are arranged at regular intervals as shown in the figure. Are arranged on the same plane to form a plane cooling pipe group a. The plane cooling pipe group a is slightly shifted in the same direction in the quenching cylinder 2 sequentially, and is formed in a checkered cross section. And a flow path F of exhaust gas is formed between the cooling pipes 5 from above to below.

The plane cooling pipe groups a, a,... Arranged at multi-stage intervals include plane cooling groups a, a,. The cooling medium introduction port 6 and the cooling medium introduction port 7 are provided in one or two blocks adjacent to each other in the vertical direction in the opposite direction so as to increase the cooling effect. The inlet 6 and the outlet 7 are respectively formed at two places as shown in the figure, and if necessary, a cooling medium spreading chamber (see FIG. (Not shown) to effectively maintain the dispersion and aggregation of the cooling medium.

By the way, the quenching cylinder 2 has an upper opening 3.
From the bottom to the lower opening 4, a required number of stages are provided, and a plurality of stages are arranged in the direction orthogonal to the longitudinal direction of the heat exchange cooling tubes in the direction in which the high-temperature gas passes through the plane cooling tube groups a. In order to gradually reduce the length in a stepwise manner and gradually reduce the opening area, for example, as shown in FIG. It is formed as a shape with a reduced flow volume corresponding to the flow rate whose volume is reduced by rapid cooling of the inflowing high-temperature exhaust gas.

It should be noted that the step portion t is formed only on one side of the cylindrical peripheral surface, and is not formed on the other side.

Reference numeral 8 denotes a mounting flange provided at a necessary position of the cooling cylinder 2.

The operation will be described based on the configuration described above.

The case where cooling air is used as the cooling medium will be described.

Introducing opening 3 of quenching cylinder 2 of quenching device 1
Then, a high-temperature gas having a temperature equal to or higher than the decomposition temperature of dioxins, for example, 800 ° C. to 900 ° C., is introduced at a desired flow rate at a desired pressure under exhaust gas exhausted from various furnaces.

On the other hand, cooling air of normal temperature or low temperature flows into the cooling pipes 5 from the inlets 6 of the plane cooling pipe groups a, a... Heat is effectively exchanged with the high-temperature gas through the pipe wall of No. 5 to be turned into a hot gas and discharged from the outlet 7.

As the high-temperature gas goes from the upper portion to the lower portion of the quenching cylinder 2, it is quenched by the multistage flat cooling tube groups a, a,.
The volume gradually decreases as the temperature gradually decreases.

Since the quenching cylinder 2 gradually decreases its opening area through a stepped step t as it goes from the upper introduction opening 3 to the lower outlet opening 4, it has a narrow cylindrical peripheral surface. The flow rate of the high-temperature gas to be treated, whose volume has been reduced by cooling, is substantially the same as the flow rate at the time of flowing from the introduction opening 3 of the quenching cylinder 2, and is maintained at substantially the same flow rate in the quenching cylinder 2. The gas that has passed through and can be led out as a gas that has dropped to a desired low temperature through the lower outlet opening 4.

In order to effectively quench the high-temperature gas, it is better to increase the temperature difference between the high-temperature gas and the cooling medium. In this embodiment, however, the group of flat cooling pipes a, Since the block configuration of a ... has the cooling gas left and right alternately traveling in different directions, the temperature difference of the contact surface of the high-temperature gas with the cooling pipe 5 can be obviously increased as much as possible. The gas can be rapidly cooled.

In particular, when the high-temperature gas is an exhaust gas that recombines dioxins in a cooling process, the temperature of the exhaust gas is higher than the decomposition temperature.
From the high temperature state of 00 ° C. to 900 ° C., the temperature must be rapidly cooled from about 300 ° C., which is referred to as the dioxin resynthesis temperature, to 200 ° C. or less. Although the treatment must be performed within a very short time of less than seconds, the high-temperature exhaust gas of 800 ° C. can be cooled very efficiently and can be rapidly cooled to a temperature lower than the regeneration temperature of dioxin.

As described above, one embodiment of the quenching device according to the present invention has been described, but a liquid such as cooling water may be used instead of cooling air as a cooling medium.

Further, although not shown, when the low-temperature quenching treatment is performed as exhaust gas such as high-temperature waste gas, when the dioxins are not completely decomposed at a low temperature of 700 to 800 ° C. including dioxins, In the reheating, dioxins are completely decomposed, and if there is a floating mist in the exhaust gas, the mist is removed by passing through a high-temperature multicyclone and maintained at a high temperature of 800 ° C. or more, and each of the quenching cylinders It is necessary to introduce it into the introduction opening 3 of the body 2.

It has been experimentally found that the high-temperature exhaust gas heated to 800 ° C. is discharged at a low temperature of about 30 ° C. to 35 ° C., and the amount of dioxins is also 100% of the reference value. It has been found by measurement that the amount is extremely small, from 1/1000 to 1/1000.

[0033]

According to the present invention, high-temperature exhaust gas such as waste gas exhausted from various furnaces can be rapidly cooled, so that it can be used by being incorporated in a part of a plant such as a combustion furnace or a melting furnace. At the same time, the standard value set by the government for the resynthesis of dioxins, which is said to be generated from various incinerators and the like used for waste treatment, that is, 0,0 for waste incinerators with a treatment capacity of 4 t / h or more. 1ng-TEQ /
Since it can be prevented almost completely by holding it to m ³ N or less, it can be compactly and easily incorporated into a part of an existing or newly installed combustion system.

Further, according to the present invention, since the configuration is simple, it is inexpensive and suitable for mass production.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part configuration showing an embodiment of a rapid cooling device according to the present invention, and is a vertical sectional view taken along line II of FIG. 2;

[Fig. 2] Side view

FIG. 3 is a schematic slope view

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Quenching device 2 Quenching cylinder 3 Exhaust gas introduction opening 4 Exhaust gas outlet opening 5 Cooling pipe is shown, and the sectional view shown is simply indicated by a circle without thickness 6 Inlet for refrigerant 7 Refrigerant inlet Outlet a Plane cooling pipe group F High-temperature exhaust gas flow path t Step

Claims (2)

[Claims] 1. A cooling tube for heat exchange for passing a multi-stage cooling medium is provided in a quenching cylinder through which a high-temperature gas such as an exhaust gas passes from an introduction opening toward an outlet opening. A rapid cooling device characterized by gradually decreasing the cross-sectional area of the quenching cylinder according to the passing direction, wherein the length direction of the heat exchange cooling pipes provided in multiple stages in the quenching cylinder and A rapid cooling device characterized in that the length is gradually reduced in a stepwise manner in a direction perpendicular to a direction in which a high-temperature gas is introduced, so that a cross-sectional area of a quenching cylinder is reduced and changed in multiple stages. 2. A cooling pipe for heat exchange, which is provided in multiple stages in a quench tube, is disposed so as to be deviated in a checkered cross section so that high-temperature gas can be cooled while meandering. Item 2. The rapid cooling device according to Item 1.