JP2001296010A - Heat treatment method of rotary heat treatment furnace - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a problem in the conventional art that the work for charging matters to be treated in a furnace is kept waiting until the furnace temperature reaches a set temperature for treatment, and as a result the time for the work is cut down, and the working efficiency is decreased, because in the case a matter to be treated, e.g. a waste is treated in a rotary heat-treatment equipment, the charge of the waste is not started before the temperature of the rotary cylindrical body reaches a set treatment-temperature suitable for the purpose, but the furnace is at room temperature at the operation-starting time of the furnace. SOLUTION: A set temperature Fh for the initial heating is set higher than a set treatment-temperature St of the rotary heat-treatment furnace at the time of starting the operation. The furnace is rapidly heated up to the set temperature Fh. When the temperature has reached the set temperature Fh, the temperature setting is returned to the set treatment-temperature St. When the temperature becomes the set treatment-temperature, charging of matters to be treated is started. Thus, the waiting time before the start of the charging is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for heating a rotary heating furnace, in which an object to be processed is put into a rotating cylinder (rotary drum) and the object is heated and processed by an external heating means. Regarding, particularly, at the beginning of the heating operation of the rotary heating furnace, rapidly heating to the set processing temperature of the processing furnace,
The present invention relates to a processing method for shortening the time until an object to be processed is introduced and securing processing time.

[0002]

2. Description of the Related Art General waste such as municipal waste, industrial waste, shredder dust, vinyl chloride and other wastes contain a large amount of halogen substances (chlorine, bromine, iodine, fluorine, astatine), especially chlorine components. If heat treatment such as incineration is performed, chlorine-based gas (hydrogen chloride,
Chlorine) generates a large amount of gas, generates generated gas (exhaust gas), residue after incineration (processed ash), and produces highly toxic dioxins in fly ash in the exhaust gas, causing problems such as environmental pollution and deterioration of incineration equipment. generate. Therefore, technology for solving these problems has been developed, and the following technology is currently disclosed. (1) Treatment method by incineration This method involves incineration of wastes and other materials to be treated in an incinerator. When incinerating, spray an alkaline substance (lime powder) into the incinerator and incinerate it. It is made to react harmlessly with chloride-based gas (calcium chloride) in the generated exhaust gas to make the exhaust gas harmless (for example, Japanese Patent Application Laid-Open No. 54-93864). (2) Treatment method by dry distillation (pyrolysis) As this treatment method, pyrolysis is performed using a single rotary processing furnace (rotary kiln), and the discharged residue is incinerated in a later stoker, and the pyrolysis gas is reburned A method has been proposed in which a high-temperature gas generated by burning in a chamber is passed through a boiler or the like, and then guided to a reaction tower, where the slaked lime slurry is sprayed and reacted with exhaust gas in the same manner as described above. (For example, JP-A-5-33916).

Further, the applicant of the present application uses a plurality of rotary processing furnaces, heats an object to be processed in a first heat processing furnace to decompose and precipitate a halogen substance, and then removes the halogen substance. A treatment method has been proposed in which the material to be treated is carbonized (or incinerated) in another second heat treatment furnace to reduce the volume, and a carbide free of a halogen substance is taken out and reused (Japanese Patent Laid-Open No. Hei 11 (1999)). −21040 to JP-A-11-21104
2).

Further, the object to be treated and the treating agent for the alkaline substance are heat-treated in a first heat treatment furnace to decompose and precipitate the halogen substance and simultaneously react with the treating agent to form harmless chloride. Detoxify the generated gas and residue, and then reduce the volume by carbonizing (ashing) the detoxified material in another second heat treatment furnace, and take out carbides containing no halogen substance. It has also been proposed to enable re-use (Japanese Unexamined Patent Application Publication No. 11-226545
-226548).

[0005] Fig. 2 is a conceptual diagram of the basic structure of the rotary heat treatment apparatus for performing the detoxification treatment. In the figure, reference numeral 10 denotes a first heat treatment furnace, and 20 denotes a second heat treatment furnace.

The first heat treatment furnace 10 includes a rotatable rotating cylinder 11, a heating jacket 12 for forming a gas duct on the outer periphery of the rotating cylinder 11, and heating the rotating cylinder 11 by introducing a hot gas. A supply port 13 provided at one end of the rotating cylindrical body 11 for supplying the object to be processed into the rotating cylindrical body 11, and a discharge port 14 provided at the other end of the rotating cylindrical body 11. The rotating cylinder 11 is driven to rotate by rotation driving means (not shown).

The rotation driving means of the rotary cylinder 11 is composed of a normal drive motor, a drive gear, a driven gear provided on the rotary cylinder, and the like. The heating jacket 12 is fixed, and a mechanical seal P is applied to a rotating contact portion with the rotating cylindrical body 11.

Reference numeral 15 denotes a supply port 13 of the first heat treatment furnace 10.
The mixture of the object to be treated and the dechlorinating agent is introduced into the rotating cylinder 11 through a supply duct provided on the side.

The structure of the second heat treatment furnace 20 is substantially the same as the structure of the first heat treatment furnace 10, and includes a rotatable rotating cylinder 21 and a hot gas A heating jacket 22 for heating the rotating cylinder 21 by the introduction of the first cylinder, and one end of the rotating cylinder 21,
And a supply port 23 provided on the discharge port 14 side of the heat treatment furnace 10 for supplying an object to be processed into the rotary cylinder 21 and a discharge port 24 provided at the other end of the rotary cylinder 21. Have been.

Reference numeral 16 denotes an outlet 14 of the first heat treatment furnace 10.
Side and the supply port 23 side of the second heat treatment furnace 20,
1 shows an introduction duct for introducing an object to be processed in a first heat treatment furnace 10 from a first heat treatment furnace 10 to a second heat treatment furnace 20.

Reference numeral 25 denotes a melting tank (not shown) which surrounds the discharge port 24 side of the rotary cylindrical body 21 of the second heat treatment furnace 20 and heats the object to be treated (residue) in the second heat treatment furnace 20. This is a discharge duct that discharges to the like.

Rotating cylindrical body 11 of first heat treatment furnace 10
And the rotating cylindrical body 21 of the second heat treatment furnace 20 are vertically arranged, and although not shown, the rotating cylindrical body 11
Heating jackets 12 and 2 provided on the outer periphery of
Numeral 1 is supported and fixed by a fixing member.
A plurality of blades for transferring the mixture of the object to be treated and the dechlorinating agent while stirring are provided in the insides of the rotary cylinders 11 and 21, and the mixture is rotated by the rotation of the rotary cylinders 11 and 21 as shown by a dashed line in the figure. It is configured to transfer from the supply port 13 side to the discharge port 24 side.

A mechanical seal P is applied to the contact portions of the ducts 15 and 16 that are in rotational contact with the rotating cylinder 11 and the contact portions of the ducts 16 and 25 that are in contact with the rotating cylinder 21.

Reference numeral 30 denotes a hopper. The crushed object and a dechlorinating agent composed of an alkaline substance are mixed and thrown into the hopper 30, and can be supplied from the supply port 13 of the rotating cylinder 11 into the rotating cylinder 11. And

The hopper 30 may have both the function of crushing the object to be treated and the function of mixing the dechlorinating agent, and may mix the dechlorinating agent while crushing the solid, The material and the dechlorinating agent may be mixed and charged into the hopper 30.

Reference numeral 31 denotes a hot blast stove, for example, LNG, LP
A fuel such as G or petroleum is burned to generate hot gas. This hot gas is supplied into a heating jacket 22 provided on the outer periphery of the rotating cylindrical body 21 of the second heating processing furnace 20 to heat the rotating cylindrical body 21, and then the first heating processing furnace is connected via the connecting pipe 26. It is fed into the heating jacket 12 of the rotating cylinder 11 of FIG. At this time, fresh cooling air is taken into the connecting pipe 26 to adjust the temperature of the hot gas. Reference numeral 27 denotes the adjusting means.

Reference numeral 32 denotes a circulation blower,
The hot gas in the 0 heating jacket 12 is sucked, and a part or all of the hot gas is sent to the hot blast stove 31 through the control valve 33 and circulated, thereby effectively utilizing the hot gas.

As another method of effectively using the hot gas, a part or all of the hot gas is discharged from the control valve 33 to the discharge pipe 34.
And heat can be recovered and used by a heat exchanger or the like.

Reference numeral 35 denotes an exhaust gas combustion means. The exhaust gas combustion means 35 introduces gas in the introduction duct 16 which connects the discharge side of the first heat treatment furnace 10 and the supply side of the second heat treatment furnace 20. The fuel is discharged through an exhaust gas purifying device (eg, a bag filter) not shown.

In the heat treatment of the object to be treated such as waste, the object to be treated is crushed in advance by a crusher, and an alkali substance as a dechlorinating agent is added to the object to be treated and mixed. This dechlorinating agent is used in any of a lump, a plate, a porous form, a powder, a suspension, or a combination thereof.

The materials to be treated include various kinds of waste (general waste, industrial waste, etc.), sludge, incinerated ash, fly ash, contaminated soil, construction waste, various types of shredder dust, metal scrap, and the like. is there.

Next, the hot gas generated in the hot blast stove 31 is supplied to the heating jacket 22 and the heating jacket 12, so that the insides of the first and second heat treatment furnaces 10 and 20 are heated. After the temperature reaches a predetermined set processing temperature, the mixture of the object to be processed and the dechlorinating agent is supplied from the hopper 30 through the supply port 13 into the rotary cylindrical body 11 of the first heat treatment furnace 10. The rotating cylinder 11 is driven to rotate by a rotation driving means (not shown).

The heat treatment in the first heat treatment furnace 10 is for carrying out a drying and dechlorination treatment, for example, by setting the treatment temperature to 350 ° C. and heating the second heat treatment furnace 20. In the heat treatment in, when the volume reduction treatment by carbonization is performed, the heating is performed with the set treatment temperature set to 600 ° C.

The temperature of the second heat treatment furnace 20 is controlled by controlling the amount of fuel supplied from the hot blast stove 31. The temperature control of the first heat treatment furnace 10 is provided in the connecting pipe 26. The adjustment is performed by controlling the introduction amount of the temperature adjusting air by the adjusting means 27.

The heat treatment in the first and second heat treatment furnaces is not a "combustion and incineration" but a dry distillation treatment and a "steaming and pyrolysis" treatment. And reacts with the treating agent to form harmless salts.

As the treating agent to be mixed or added with the article to be treated, use is made of an alkali substance which forms a harmless chloride by reacting at least with HCl (hydrogen chloride). For example, JP-A-9-155326, JP-A-10-43731, and JP-A-10-235186, which the applicant of the present application previously filed,
As shown in JP-A-10-235187, alkaline earth metals, alkaline earth metal compounds, alkali metals, and alkali metal compounds, specifically, calcium, lime, slaked lime, calcium carbonate, dolomite, silicate (calcium silicate) Sodium bicarbonate, sodium carbonate, sodium sesquicarbonate, natural soda, sodium hydroxide,
One kind is selected from potassium hydroxide, potassium hydrogen carbonate, and potassium carbonate, or several kinds are mixed and used. As an amount to be used, 5 to 30% by weight based on the material to be treated is mixed or added.

For example, sodium bicarbonate (Na
When HCO ₃ ) is used, a decomposition gas of the HCl component is generated in the dechlorination furnace which is the first heat treatment furnace.
Immediately reacts with sodium carbonate (NaHCO ₃ ) +
(HCl) → (NaCl) + (H ₂ O) + (CO ₂ ), producing harmless sodium chloride (NaCl) and eliminating harmful HCl from the decomposition gas. This allows
The detoxification of the HCl component in the cracked gas and the detoxification of the residue are performed simultaneously.

The object to be treated after the harmful components have been deposited is fed into the supply port 23 of the rotary cylindrical body 21 of the second heat treatment furnace 20 through the introduction duct 16, where the temperature at which the object to be treated is carbonized is increased. The carbonization treatment is performed by heating to the above set treatment temperature of 600 ° C.

On the other hand, the exhaust gas generated in the first and second heat treatment furnaces 10 and 20 is introduced into an exhaust gas combustion means 35 and burns at a temperature of 800 ° C. or more to decompose tar components and residual harmful substances. Remove.

The set processing temperature of the first and second heat treatment furnaces 10 and 20 is the temperature inside the rotary cylinder, for example, as previously proposed by the present inventor and disclosed in Japanese Patent Application Laid-Open No. H11-30943.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-260, a temperature detection sensor including a through pipe extending in the axial direction of the rotating cylinder is provided in the rotating cylinder, the temperature in the rotating cylinder is detected, and the set processing temperature is: Utilizing this detection signal, fuel supply to the hot blast stove 31 and control of the circulating hot gas by the control valve 33 and control of the adjusting means 27 and the like are performed.

[0031]

The heat treatment in the first heat treatment furnace 10, for example, the set treatment temperature (350 ° C.) for the drying and dechlorination treatment, and the second heat treatment furnace 20 Set processing temperature (600
C) is a temperature applied to the object to be processed, which is a condition necessary for stably heating the object to be processed.

However, the heating means in each heat treatment furnace is external heating, and at the start of the heating operation of the rotary heat treatment furnace in the heat treatment apparatus, the heat treatment furnace, the duct, and other equipment are cooled to near normal temperature. The first and second
The temperature of the heat treatment furnaces 10 and 20 was set at 350 ° C.
At a temperature of 600 ° C., a hot gas is generated in a hot blast furnace 31, introduced into the heating jacket 22 of the second heating furnace 20, and further connected to the heating jacket of the first heating furnace 10 via the connecting pipe 26. Since each of the rotating cylinders 21 and 11 is heated by being introduced into the heater 12, a considerably long heating operation time (t ₄ ) is required until the respective set processing temperatures are reached, as shown by a dotted line B in FIG. Cost.

Since the object to be processed starts to be charged at least after the first heat treatment furnace 10 reaches the set processing temperature,
The time to start loading the object to be processed is delayed by that much (for example, 2
Time), there is a problem that the actual working time of one day for processing the workpiece is reduced, and the working efficiency is deteriorated.

The present invention has been made to solve the problems of the prior art, and has as its object to shorten the time until the start of loading of the object to be processed and to improve the working efficiency.

[0035]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and in order to shorten the time until the start of loading of an object to be processed, a normal setting is performed at the beginning of heating of a rotary heating furnace. By setting the initial heating set temperature to a temperature equal to or higher than the processing temperature and heating, and then returning to the normal set processing temperature, the time required to reach the set processing temperature is shortened and the working efficiency is improved.

That is, this is a method for heating a rotary heating furnace in which an object to be processed is charged into a rotating cylinder having an external heating means and is heated at a predetermined set processing temperature. In the initial stage of heating, heating is performed by setting an initial heating set temperature higher than the set processing temperature, and after reaching the initial heating set temperature, the initial heating set temperature is held for a certain period of time, and then reset to the set processing temperature. Then, heating is controlled, and after the temperature reaches the set processing temperature, an object to be processed is charged.

The heat treatment of the object to be treated may be any of drying, dechlorination, carbonization, and incineration, and a desired heat treatment can be realized by setting a treatment temperature suitable for the purpose of treatment and heating. .

The above-mentioned initial heating set temperature is desirably 100 ° C. or more higher than the set processing temperature.

The external heating means may be either hot gas heating or electric heating or a combination of both.

[0040]

FIG. 1 is a block diagram showing an embodiment of the present invention.
It will be explained by.

FIG. 1 is a characteristic diagram showing a heating operation time required to reach a predetermined heating temperature range for explaining the processing method of the present invention. The vertical axis represents temperature (° C.), and the horizontal axis represents heating operation. Time (T) is shown, A represents the present invention, and B represents the conventional characteristics.

Now, the first and second heat treatment furnaces 10 shown in FIG.
Assuming that the temperatures inside the rotating cylinders 11 and 21 are (a) and (b) and the temperatures inside the heating jackets 12 and 22 are (c) and (d), the temperatures inside the rotating cylinder (a) and (b)
Are the conditions necessary to stably heat the object to be treated, and the temperatures (c) and (d) in the heating jacket are necessary to secure the temperatures (a) and (b) in the rotating cylinder. Under the conditions, since the heating jacket has external heat radiation, the temperatures (c) and (d) in the heating jacket are generally higher than the temperatures (b) and (b) in the rotating cylinder. ing.

Therefore, in the present invention, at the start of the heating operation of the rotary heating furnace in the rotary heating apparatus, the initial heating set temperature Fh in the rotary cylinder is higher than the set processing temperature St in the rotary cylinder by 100 ° C. or more (for example, (+ 500 ° C.) Set the heating temperature. This set processing temperature St is set to a temperature suitable for processing purposes such as drying / dechlorination, carbonization, and incineration.

Taking an example of the drying and dechlorination treatment assuming that the set treatment temperature St suitable for this treatment purpose is 350 ° C., the initial heating temperature Fh in the rotating cylinder is set to 850 ° C. and set to 850 ° C. Heat briefly (t ₁ ) until reached.
After the temperature reaches 850 ° C., the temperature is held for a certain time (t ₂ ), and then the setting is returned to the normal set processing temperature of 350 ° C.
At the time (t ₃ ), charging of the object to be processed is started.

The heating and temperature are controlled by detecting the temperature in the rotating cylinder with the temperature detection sensor as described above, and using this detection signal to supply fuel (LNG, etc.) to the hot blast stove 31 and to connect the pipe. Adjustment of the amount of cooling air introduced into 26,
By controlling the amount of the circulating hot gas returned to the hot blast stove 31 after heating the first heat treatment furnace 10, the temperatures (c) and (d) in the heat jacket are controlled.

In FIG. 2, the heating by the hot gas is used as the external heating means. However, the heating is not limited to the hot gas heating, but may be electric heating (induction heating, resistance heating, microwave heating).
Heating may be used in combination.

In the present invention, as shown by the solid line A in FIG. 1, at the initial stage of heating in the heating operation of the rotary heating furnace, the heating is performed by setting the initial heating set temperature Fh, and after reaching the initial heating set temperature Fh ( t ₁ ), the temperature Fh is held for a predetermined time (t ₂ ), and then the heating is controlled by setting the temperature to the original set processing temperature St, and after reaching the set processing temperature St, the rotary heating furnace is set. Since the loading of the workpiece is started, the time from the start of the operation to the loading of the workpiece is t ₁ + t ₂ + t ₃
Becomes

On the other hand, when the temperature inside the rotary cylinder is set to the set processing temperature St from the beginning and heated as in the conventional case, as shown by the dotted line B in FIG. operation time is t ₄ of. Therefore, the present invention, when compared with the conventional method, is t ₄ − (t ₁ + t ₂ + t ₃ ) =
t ₅ hours can only put the start time of the workpiece is faster.

If the time to start loading the workpiece is delayed, for example, by two hours, the operator must be monitoring during that time, which not only wastes waiting time but also increases energy costs. On the other hand, if the charging of the object to be processed can be started in a short time as in the present invention, the work time per day, that is, the processing time of the object to be processed can be increased, and the work efficiency can be improved.

[0050]

As described above, according to the present invention, at the start of the heating operation, the initial heating set temperature in the rotating cylinder is set to a temperature higher than the normal set processing temperature, and the temperature reaches the initial heating set temperature. After that, the temperature is returned to the set processing temperature and heated, and after reaching the set processing temperature, the object to be processed is put into the rotary heating processing furnace. Can be shortened. Therefore, since it is possible to secure the working time after the introduction, it is possible to reliably process a predetermined amount of the workpiece,
This produces effects such as stabilizing the work rotation.

[Brief description of the drawings]

FIG. 1 is an explanatory characteristic diagram of the present invention.

FIG. 2 is a conceptual diagram of a basic configuration of a rotary heating apparatus.

[Explanation of symbols]

 Reference Signs List 10 first heat treatment furnace 11, 21 rotating cylinder 12, 22 heating jacket 13, 23 supply port 14, 24 discharge port 15 supply duct 16 introduction duct 26 communication pipe 27 adjusting means DESCRIPTION OF SYMBOLS 30 ... Hopper 31 ... Hot-blast furnace 32 ... Circulation blower 33 ... Control valve 34 ... Discharge pipe 35 ... Exhaust gas combustion means

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Takayuki Tanabe 2-1-1-17 Osaki, Shinagawa-ku, Tokyo F-term in Meidensha Co., Ltd. (Reference) 3K061 AA07 AC20 GA05 GA08 KA02 KA13 4D004 AA08 AA28 AA46 AB06 CA26 CA42 CB09 DA01 DA02 DA03 DA06 4K061 AA08 BA12 CA02 DA05 DA07 FA06 GA02

Claims (4)

[Claims] 1. A heating method for a rotary heating furnace in which an object to be processed is charged into a rotating cylinder having an external heating means and heat-treated at a predetermined set processing temperature. At the initial stage of heating, heating is performed by setting an initial heating set temperature higher than the set processing temperature, and after reaching the initial heating set temperature, the initial heating set temperature is held for a certain period of time, and then the set processing temperature is set. A heating treatment method for the rotary heating furnace, wherein the object to be treated is charged after reaching the set processing temperature. 2. The heat treatment of the object to be processed includes drying, dechlorination,
The heat treatment method for a rotary heat treatment furnace according to claim 1, wherein the heat treatment is performed for any of carbonization and incineration. 3. The method according to claim 1, wherein the initial heating set temperature is at least 100 ° C. higher than the set processing temperature.
A heat treatment method for the rotary heat treatment furnace according to the above. 4. The method for heating a rotary heating furnace according to claim 1, wherein the external heating means is hot gas heating, electric heating or a combination of both.