JP2004316944A - Combustion heating system and combustion heating method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce fuel consumption by effectively removing an odor component in exhaust gas and the volatile content from a heating object. <P>SOLUTION: This combustion heating system has a combustion chamber 10 having a burner 11 for supplying and burning fuel, an oxygen-enriched gas supply port 12 for performing oxygen-enriched combustion by the burner 11, an exhaust port 13 of heating gas generated by combustion, and an introducing port 14 for reintroducing a part of the heating gas coming out of the exhaust port 13; and heats the object 1 while circulating the heating gas. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a combustion heating apparatus and a combustion heating method of a heating gas circulation type utilizing oxygen-enriched combustion, and is particularly useful for drying and baking paints.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a color steel sheet in which the surface of a steel sheet is coated with a colored resin coating film, that is, a so-called pre-coated steel sheet, has been used for a wide range of uses such as a construction material field and a home appliance field. Color steel sheets were manufactured with a predetermined thickness by using a zinc iron plate or the like as an original sheet, applying paint, baking at high temperature, and repeating this painting and baking process. For example, see Patent Document 1).
[0003]
As a heating device for performing the above-described baking process, an electric furnace, a combustion furnace, or the like is used, but a combustion furnace using various fuels is more advantageous in cost than an electric furnace.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 6-102034 (page 2, FIG. 1)
[0005]
[Problems to be solved by the invention]
However, if the paint is dried and baked with a combustion heating device using kerosene, etc., an odor component (aldehydes, etc.) derived from the paint and the like is contained in the exhaust gas, so a gas treatment device for exhaust gas treatment must be separately provided. To remove it.
[0006]
In addition, the volatile components contained in the coating material become tar-like, adhere to the duct and the inner wall of the combustion heating device, and an operation for periodically removing the volatile component has been required. Further, there is a problem of reducing fuel consumption as an energy saving measure.
[0007]
On the other hand, such issues as reduction of fuel consumption, removal of odor components in exhaust gas, and prevention of adhesion of volatile components from a heating object are not limited to the case of a combustion heating apparatus used for manufacturing color steel sheets. This also poses a problem for the combustion heating device.
[0008]
Therefore, an object of the present invention is to provide a combustion heating device and a combustion heating method capable of effectively removing odor components in exhaust gas and volatile matter from a heating object and reducing fuel consumption. is there.
[0009]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the combustion method, the structure of the combustion chamber, and the like in order to achieve the above object, and found that while performing oxygen-enriched combustion in the combustion chamber, the target gas was circulated while circulating the heated gas generated by the combustion. It has been found that the object can be achieved by heating the object, and the present invention has been completed.
[0010]
That is, the combustion heating device of the present invention includes a burner for supplying and burning fuel, an oxygen-enriched gas supply port for performing oxygen-enriched combustion by the burner, and a discharge of heated gas generated by the combustion. A combustion chamber having an outlet and an inlet for re-introducing a part of the heated gas from the outlet thereof is provided, and the object is heated by the heated gas while circulating the heated gas. According to the combustion heating device of the present invention, combustion can be performed at a higher temperature than oxygen combustion in order to perform oxygen-enriched combustion, and since the heating gas (exhaust gas) is introduced again into the combustion chamber and circulated, the odor in the exhaust gas is reduced. The volatile components from the components and the object to be heated can be effectively removed. Further, the fuel consumption can be reduced as compared with the air combustion because the oxygen-enriched combustion is performed.
[0011]
In the above, a circulation blower is provided at an end of the combustion chamber on the downstream side in the fuel supply direction for sucking heated gas generated by combustion and discharging the gas from the outlet, and the inlet is provided with an oxygen gas of the burner. Preferably, it opens to the enriched combustion zone. By providing such a circulation blower, the circulation of the heating gas can be suitably performed, and at this time, the introduction port is opened toward the oxygen-enriched combustion region, so that the introduced heating gas is converted into a high-temperature flame. Because of the contact, the odor components in the exhaust gas and the volatile matter from the object to be heated can be more effectively removed.
[0012]
On the other hand, the combustion heating method of the present invention supplies oxygen-enriched gas while supplying fuel to the burner, performs oxygen-enriched combustion in the combustion chamber, and discharges the heated gas generated by the combustion from the combustion chamber. A part is introduced again and circulated, and the object is heated by the heated gas. According to the combustion heating method of the present invention, the oxygen-enriched combustion can be performed at a higher temperature than the air combustion, and the heated gas (exhaust gas) is again introduced into the combustion chamber and circulated, so that the odor in the exhaust gas The volatile components from the components and the object to be heated can be effectively removed. Further, the fuel consumption can be reduced as compared with the air combustion because the oxygen-enriched combustion is performed.
[0013]
In the above, the object to be heated is a long body coated with paint, and while moving the long body in the heating chamber, while discharging a part of the heating gas introduced into the heating chamber to the outside of the system. Preferably, at least the coating is continuously dried. When used for drying paints, etc., especially when volatile components contained in the paint are in the form of tar and easily attach to the inner wall of the duct or combustion heating device, the volatile matter from the heating target is effectively removed. The present invention, which can be removed in particular, is particularly effective. In the case of a continuous process, while the long body is moved in the heating chamber, a part of the heating gas introduced into the heating chamber is discharged out of the system, thereby concentrating the volatile components contained in the paint. It is possible to perform continuous drying of the paint while suppressing the decrease. Furthermore, combustible substances (organic substances, thinners, etc.) contained in the paint are introduced into the combustion chamber by circulation and can be burned, so that the fuel consumption can be further reduced by about 1 to 3% (energy saving effect). can get.
[0014]
Further, a liquid or gas fuel can be suitably used as the fuel. Particularly, when a liquid fuel is used, odorous substances derived from the fuel may be contained in the exhaust gas, and these odorous substances are effectively decomposed. The present invention that can be made is particularly effective.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic plan view showing an example of the combustion heating device of the present invention, and FIG. 2 is a partially broken perspective view showing details of a combustion chamber of the device.
[0016]
As shown in FIG. 1, the combustion heating device of the present invention includes a combustion chamber 10 for generating a heating gas, and heats an object 1 with the heating gas while circulating the heating gas. In the present embodiment, the object 1 is a long body coated with a paint, and while moving the long body in the heating chamber 20, a part of the heating gas introduced into the heating chamber 20 is moved out of the system. An example in which drying and baking of paint are continuously performed while discharging the paint will be described.
[0017]
As shown in FIG. 2, the combustion chamber 10 includes a burner 11 for supplying and burning fuel, an oxygen-enriched gas supply port 12 for performing oxygen-enriched combustion by the burner 11, and a combustion chamber formed by the combustion. It has an outlet 13 for the heated gas and an inlet 14 for re-introducing a part of the heated gas coming out of the outlet 13. In the present embodiment, an example is shown in which a circulation blower 15 for smoothly circulating the heating gas is provided (in FIG. 2, the circulation blower is omitted).
[0018]
The burner 11 may be any of a burner for gaseous fuel, a burner for liquid fuel, a burner for solid fuel, and the like, and can be selected according to the heating temperature of the object. Examples of the fuel to be used include kerosene, heavy oil, gasoline, alcohol, natural gas, propane gas, butane gas, hydrogen, and the like.However, when using a fuel in which odorous substances in exhaust gas are likely to be a problem, the present invention is particularly effective. Become. The supply of fuel to the burner 11 can be performed in the same manner as in the case of air combustion. However, according to the present invention, the fuel consumption can be reduced as compared with the case of air combustion, as described later. It can be reduced by about 40%.
[0019]
One or more burners 11 can be provided, and it is preferable that the burners 11 be provided on the wall surface at one end in the combustion chamber 10. When the fuel is supplied from the burner 11 in the case of a drum type or the like, it is preferable that the wall surface at the other end be downstream of the supply.
[0020]
In the present invention, the supply port 12 of the oxygen-enriched gas for performing the oxygen-enriched combustion in the burner 11 is provided, but can also be used as the burner 11 as described later. In the present embodiment, a supply port 12 for the oxygen-enriched gas is separately provided, and oxygen gas is blown as the oxygen-enriched gas. For example, two lances 12a are used for blowing the oxygen gas, and a nozzle 12b for adjusting the blowing direction is attached to the tip of the lances 12a.
[0021]
For the supply of oxygen gas, a liquid oxygen storage tank equipped with an evaporator, an oxygen gas cylinder, and the like are used, and a flow rate control device, a pressure control device, and the like are used as needed. When a gas having a low oxygen concentration is used as the oxygen-enriched gas, a nitrogen gas, air, or the like may be appropriately mixed.
[0022]
The blowing direction of the oxygen-enriched gas from the nozzle 12b is preferably on the upstream side in the fuel supply direction from the position where the heating gas introduced for circulation from the inlet 14 and the flame of the burner 11 intersect. In other words, the inlet 14 preferably opens toward the oxygen-enriched combustion region of the burner 11. In order to ensure that the circulating heating gas is in contact with the flame that has undergone the oxygen-enriched combustion, the oxygen-enriched gas is blown from a position near the burner 11 at an angle close to parallel to the fuel supply direction from the burner 11. It is preferred to do so. For the same reason, the linear velocity of the supply section of the oxygen-enriched gas is preferably 20 to 80 m / s.
[0023]
The oxygen concentration in the supplied oxygen-enriched gas may be higher than that of air, but is preferably 50% by volume or more, and pure oxygen gas is most preferable. The supply rate of the oxygen-enriched gas is preferably 1.0 to 1.5 of the theoretical oxygen amount for complete combustion with respect to the fuel supply rate to the burner 11.
[0024]
Oxygen-enriched combustion can theoretically raise the flame temperature by 600 to 800 ° C. as compared with normal air combustion, so that the air-enriched combustion and the oxygen concentration depend on the blowing state of the oxygen-enriched gas and its oxygen concentration. It is preferable that the flame temperature rises by 300 ° C. or more in comparison. For this purpose, the target is to have an oxygen concentration of 50% or more in a flame region where oxygen-enriched combustion occurs.
[0025]
The discharge port 13 is a part that discharges the heating gas generated by the combustion to the heating chamber 20. In order to circulate the heated gas, it is sufficient that the pressure of the combustion chamber 10 at the outlet 13 is high and the pressure of the combustion chamber 10 at the inlet 14 is low. In the present embodiment, a circulation blower 15 is provided at an end of the combustion chamber 10 on the downstream side in the fuel supply direction in order to smoothly circulate such a heated gas. The circulating blower 15 may be of any type as long as it draws heated gas generated by combustion from the suction port 15a and discharges it from the discharge port 13. In the case of the structure shown in the drawing, a single suction type is used. A centrifugal blower such as is suitable. By controlling the circulation blower 15, the amount of the heated gas discharged from the outlet 13 and the amount of the heated gas introduced from the inlet 14 can be controlled.
[0026]
The amount of the heating gas introduced from the introduction port 14 is preferably set to 0.01 to 2 seconds in terms of the average residence time in the combustion chamber 10 in one pass from the viewpoint of removing organic substances in the exhaust gas.
[0027]
Further, the discharge amount from the exhaust gas discharge passage 21 provided in the heating chamber 20 is preferably 1 to 10% of the heating gas introduced for circulation from the inlet 14 on the basis of normal volume conversion.
[0028]
The combustion heating method of the present invention performs oxygen-enriched combustion in the combustion chamber 10 by supplying an oxygen-enriched gas while supplying fuel to the burner 11 by using the above-described combustion heating device or the like. The heating gas generated by the combustion is discharged from the combustion chamber 10 while a part of the heating gas is re-introduced and circulated, and the object 1 is heated by the heating gas.
[0029]
As shown in FIG. 1, when the object 1 to be heated is a long body coated with paint, while moving the long body in the heating chamber 20, one of the heating gas introduced into the heating chamber 20 is removed. It is preferable to continuously dry at least the paint while discharging the part out of the system. FIG. 3 shows equipment for manufacturing a color steel sheet in which the surface of a steel sheet is coated with a colored resin coating film, that is, a so-called pre-coated steel sheet.
[0030]
In this equipment, a zinc-iron plate or the like is used as a base plate, and while a coil-shaped base plate is fed from a base plate feed unit 22, a coating material is applied by a first coating unit 23 a of a roll coater type coating device 23, and then the heating chamber 20 is heated. Is moved, and the paint is dried and baked with the heating gas supplied from the combustion chamber 10. After passing through the cooling device 25, the coating is performed again in the second coating unit 23 b. After drying / baking and cooling by the cooling device 26, the product is taken up by the product take-up unit 28 via the outlet-side accumulator 27 (the inlet side is not shown). The original plate may be subjected to a chemical conversion treatment or the like, or a plurality of original plates joined by a stitcher.
[0031]
When a paint such as a polyester resin paint is dried and baked as described above, for example, the gas temperature at the heating gas outlet 13 is 300 to 500 ° C., and the gas temperature at the heating gas inlet 14 is 200 to 350 ° C. Set to about ° C.
[0032]
[Other embodiments]
(1) In the above-described embodiment, an example is described in which an oxygen-enriched gas supply port is separately provided and oxygen gas is blown as the oxygen-enriched gas. However, when gaseous fuel or solid fuel is used, atomization is performed. Since oxygen-enriched combustion can be performed by enriching oxygen as air or carrier gas for use, the fuel supply port to the burner may also serve as the oxygen-enriched gas supply port. In this case, it is not necessary to provide a supply port for the oxygen-enriched gas, but both may supply the oxygen-enriched gas.
[0033]
(2) In the above-described embodiment, the example in which the circulation blower is provided at the downstream end of the combustion chamber in the fuel supply direction has been described. However, the circulation blower is provided in a duct portion connecting the combustion chamber and the heating chamber. It is also possible to provide them on the heating chamber side.
[0034]
(3) In the above-described embodiment, an example is shown in which the combustion heating device of the present invention is used for drying and baking of paint for producing a color steel sheet. However, the present invention is not limited to this, and it is not limited to this. It can be widely used as an industrial or industrial heating device for metal coating.
[0035]
(4) In the above-described embodiment, the example of the combustion heating device including the drum-type combustion chamber is shown. However, in the present invention, the combustion chamber is not limited to the drum type or the like, and any shape of the combustion chamber is adopted. It is also possible.
[0036]
【Example】
Hereinafter, examples and the like that specifically show the configuration and effects of the present invention will be described.
[0037]
Example 1
Using a combustion heating device (two combustion chambers) as shown in FIGS. 1 and 2, 80 Nm ³ / hr (linear velocity of the supply unit: about 50 m / s) from two lances in each combustion chamber. The set temperature is set to 200 ° C. in the first combustion chamber and 250 ° C. in the second combustion chamber while supplying oxygen gas, using kerosene as fuel, and supplying air to the spray nozzle at 1291 Nm ³ / hr. Was heated. The flow rate of the heating gas discharged from each combustion chamber to the heating chamber is 28200 Nm ³ / hr, the flow rate of the heating gas introduced into the combustion chamber is 19500 Nm ³ / hr, and the discharge is from the exhaust gas discharge passage provided in the heating chamber. The amount was 4800 Nm ³ / hr.
[0038]
Comparative Example 1
In Example 1, heating by air combustion was performed in the same manner as in Example 1 except that the supplied air amount (primary air + secondary air) was set to 2987 Nm ³ / hr without supplying oxygen gas. .
[0039]
Evaluation Results When the set temperature of each combustion chamber was the same in Example 1 and Comparative Example 1, the fuel flow rate in Comparative Example 1 was 50 L / hr, whereas the fuel flow rate in Example 1 was 35 L / hr. This has enabled a 30% reduction in fuel consumption.
[0040]
Further, the content of the odorous substance contained in the exhaust gas from the exhaust gas discharge passage provided in the heating chamber was measured using a gas chromatograph. The results are shown in FIG. 4. As shown in FIG. 4, most of the odorous substances were removed (below the detection limit) in Example 1 in which the oxygen-enriched combustion was performed.
[Brief description of the drawings]
FIG. 1 is a schematic plan view showing an example of a combustion heating device of the present invention. FIG. 2 is a partially cutaway perspective view showing details of a combustion chamber of the combustion heating device of the present invention. FIG. FIG. 4 is a schematic diagram showing an example of the use of the gas. FIG. 4 is a graph showing the results of measuring the concentration of odorous substances in exhaust gas in the examples.
DESCRIPTION OF SYMBOLS 1 Heated object 10 Combustion chamber 11 Burner 12 Oxygen-enriched gas supply port 13 Heated gas outlet 14 Heated gas inlet 15 Circulating blower 20 Heating chamber 21 Exhaust gas discharge passage

Claims (5)

A burner that supplies and burns fuel, a supply port for oxygen-enriched gas for performing oxygen-enriched combustion with the burner, an outlet for heated gas generated by the combustion, and heating output from the outlet. A combustion heating device, comprising: a combustion chamber having an inlet for re-introducing a part of gas, and heating an object by the heating gas while circulating the heating gas. At the downstream end of the combustion chamber in the fuel supply direction, a circulation blower for sucking heated gas generated by combustion and discharging it from the outlet is provided, and the inlet is provided with the oxygen-enriched combustion of the burner. The combustion heating device according to claim 1, wherein the combustion heating device opens toward the region. By supplying oxygen-enriched gas while supplying fuel to the burner and performing oxygen-enriched combustion in the combustion chamber, a part of the heated gas generated by the combustion is discharged from the combustion chamber while being reintroduced and circulated. And a combustion heating method of heating an object by the heated gas. The object to be heated is a long body coated with paint, and while moving the long body in the heating chamber, at least a part of the heating gas introduced into the heating chamber is discharged outside the system, The combustion heating method according to claim 3, wherein the paint is continuously dried. 5. The combustion heating method according to claim 3, wherein the fuel is a liquid or gas fuel.

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