JPH06147778A - Tunnel kiln for baking carbon product - Google Patents

Abstract

PURPOSE:To subject produced black smoke to elimination treatment in a furnace body so that it be prevented from being discharged outside and to make it possible to maintain a prescribed heat curve without causing an increase of the cost, by providing a means for burning the black smoke and a means for replenishing the quantity of heat, which are specified respectively. CONSTITUTION:While a carbon product (a) containing tar, pitch or the like as a binder is loaded on a truck and made to run through a tunnel-shaped furnace body 1, preheating, baking and cooling are executed sequentially in conformity with temperature atmosphere of a prescribed heat curve formed in the furnace body 1. In such a tunnel kiln for baking the carbon product as stated above, means 11, 12 and 2a for burning black smoke which suck a furnace gas in the area in a preheating zone in which a furnace temperature is 350 to 800 deg.C and in which the black smoke is produced from the binder decomposed thermally and blast it into the furnace body 1 in the area of a high temperature 800 deg.C or above are provided. Moreover, means 13 to 15 for replenishing the quantity of heat which suck the furnace gas in the high- temperature area and blast it into a low-temperature area before the area of production of the black smoke in the preheating zone are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tunnel kiln suitable for firing a carbon product containing a binder such as tar or pitch which produces black smoke by thermal decomposition.

[0002]

2. Description of the Related Art The general structure of a tunnel kiln will be described with reference to FIG. 1 showing an embodiment of the present invention. A pre-tropical zone, a firing zone and a cooling zone are defined in a tunnel-shaped elongated furnace body 1. While the combustion gas is ejected from the burner 2 through the combustion port 3 in the firing zone, while the in-furnace gas is sucked and exhausted from the flue 4 by the exhaust fan 5 on the inlet side of the pre-tropical zone, A temperature atmosphere of a heat curve shown in the figure is formed, and preheating, firing and cooling are sequentially performed while the product a is placed on a trolley and travels inside the furnace body 1.

When a carbon product a containing a binder such as tar or pitch is fired in such a tunnel kiln, the binder is burned, that is, thermally decomposed as the product a is heated. Black smoke (volatile) is generated. It is known that this black smoke is less generated up to a temperature of the product a of about 350 ° C., is violently generated up to about 800 ° C. above the temperature, and self-combusts when the temperature is higher than that.

[0004]

In the conventional tunnel kiln, as described above, since the in-furnace gas is drawn to the inlet side of the pre-tropical zone, which is the low temperature part, and exhausted, the black smoke generated is generated. Even if it is not burned, it is pulled and discharged as it is, causing pollution.

As a preventive measure, exhaust gas is heated by an afterburner to burn black smoke.
This required nearly the same fuel to be used for firing the product, and had the additional problem of increased cost.

[0006]

DISCLOSURE OF THE INVENTION The tunnel kiln for burning carbon products of the present invention has been completed in view of the above points, and is a furnace in which a binder in the pretropical zone is thermally decomposed to generate black smoke. By sucking in the furnace gas in the region where the internal temperature is 350 to 800 ° C,
A means for burning black smoke to be injected into the furnace body in the high temperature range of 800 ° C or higher, and a means for supplementing the amount of heat to suck in the gas in the furnace in the high temperature area and drive it into the low temperature area before the black smoke generation area in the pre-tropical zone. Is provided.

[0007]

[Function] Black smoke is generated by the thermal decomposition of the binder in the pre-tropical furnace temperature range of 350 to 800 ° C. The furnace gas containing the black smoke is discharged by the means for burning black smoke. It is sucked and driven into a high temperature range of 800 ° C or higher, where black smoke burns and disappears.

Since the gas in the furnace is sucked in the above-mentioned black smoke generation area, the heat quantity becomes insufficient in the low temperature part before the pre-tropical zone, but the high temperature part is obtained by the heat quantity supplementing means. The in-furnace gas sucked from is driven into the low temperature part to replenish the insufficient heat amount.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. In this embodiment, in the tunnel kiln having the structure described above, the in-furnace gas suction port 11 connected to the suction fan 12 is formed on the side wall of the region where the pre-tropical in-furnace temperature is near 350 to 800 ° C. The driving destination of the suction fan 12 is connected to the combustion air supply port 2a of the burner 2.

Further, a hot air suction port 13 connected to a driving fan 14 is formed on the side wall of a high temperature part where the temperature in the pre-tropical furnace is 800 ° C. or more, and the driving fan 14 is driven into a hot air suction port 13. It is connected to the hot air blowing port 15 formed on the side wall on the inlet side where the temperature in the pre-tropical furnace becomes 350 ° C. or lower.

This embodiment has such a structure, and black smoke is generated due to the thermal decomposition of the binder contained in the carbon product a in the temperature range of 350 to 800 ° C. in the pretropical furnace. The in-furnace gas containing the black smoke is sucked from the in-furnace gas suction port 11 by the suction fan 12 and is injected as a part of the combustion air of the burner 2, whereby the black smoke is burned and disappears.

Further, since the in-furnace gas is sucked in the above black smoke generation region, the heat quantity becomes insufficient in the low temperature portion before the pre-tropical zone, but it is higher than 800 degrees Celsius in the pre-tropical zone. The in-furnace gas containing no black smoke due to self-combustion of black smoke in the high temperature part is sucked by the driving fan 14 from the hot air suction port 13 and blown into the low temperature part on the inlet side of the pre-tropical zone with hot air. It is driven in through the insertion port 15. As a result, the insufficient heat quantity in the low temperature part of the pre-tropical zone is replenished, and the predetermined heat curve is maintained.

[0013] The furnace gas containing black smoke is injected into the firing port 3 of the firing zone, the furnace body 1 of the firing zone, and
It may be a region where the temperature in the pre-tropical furnace is 800 ° C or higher.

[0014]

As described above, according to the present invention,
The generated black smoke is burnt in the high temperature part and is eliminated in the furnace body to be prevented from being discharged to the outside. Moreover, the burning process of the black smoke can be performed only by the burning fuel, which increases the cost. There is no fear of inviting.

In addition, an insufficient amount of heat in the area before the black smoke generation area in the pre-tropical zone is replenished, and a predetermined heat curve can be maintained.

[Brief description of drawings]

FIG. 1 is a configuration diagram and a heat curve graph of an embodiment of the present invention.

[Explanation of symbols]

a: carbon product 1: furnace body 2a: combustion air supply port (for burner 2) 11: furnace gas suction port 12: suction fan
13: Hot air inlet 14: Driving fan 15: Hot air inlet

Claims (1)

[Claims] 1. While a carbon product containing tar, pitch, etc. as a binder is placed on a trolley and travels in a tunnel-shaped furnace body, the temperature atmosphere of a constant heat curve formed in the furnace body is followed. In a tunnel kiln for firing carbon products, which is preheated, fired, and cooled in sequence, the binder in the preheat zone is thermally decomposed to generate black smoke. The furnace temperature is in the range of 350 to 800 ° C. Inhale gas, 8
Means for burning black smoke to be injected into the furnace body in a high temperature range of 00 ° C or higher, and for supplementing the amount of heat to be sucked into the furnace gas in the high temperature area and to be injected into the low temperature area before the black smoke generation area in the pretropical zone A tunnel kiln for firing carbon products, characterized by being provided with means.