JPH0979525A - Heat storage material for regenerative burner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the clogging of a heat storage material, to improve the regenerative function and to improve the durability by disposing large volume rough particle ceramic layer at the exhaust gas input side of a small-volume metal heat storage material, and disposing a fine particle ceramic layer on the upper layer. SOLUTION: A rough particle ceramic layer 2 of larger volume than the volume of a metal heat storage material 1 is disposed at the exhaust gas inlet side A of the material 1. A fine particle ceramic layer 3 is disposed at the upper part as a heat storage material 4. At the time of burning, the combustion air is supplied from the exhaust gas output side B of the material 4, the sensible heat stored from the material 1 and layer 2 is drawn and preheated, and supplied to the end of a burner 5. On the other hand, at the time of regenerating, high-temperature exhaust gas generated in the case of burning and overheating is sucked from the exhaust gas input side A of the material 4, the dust in the exhaust gas is captured by the layer 3, drawn to less than the refractory temperature of the material 1 by the layer 2, and then passed through the material 1, regenerated and exhausted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat storage body of a heat storage type burner.

[0002]

2. Description of the Related Art A slab (steel slab), billet (bar steel), bloom, etc. after casting is charged into a heating furnace and heated to a temperature suitable for hot rolling. Is generally composed of pre-tropics, heating zones and soaking zones,
Materials to be heated such as slabs are heated by sequentially moving the pre-tropical zone, heating zone and soaking zone in order to improve the heating efficiency. The burner groups are arranged facing each other, the one side burner group heats the combustion air through the heat storage body and supplies it to the burner to burn the fuel, and the other side burner group stops the combustion. The combustion exhaust gas in the furnace is exhausted through the heat storage body to store heat energy in the exhaust gas. As described above, continuous heating is performed by so-called heat storage type alternating combustion in which combustion and heat storage are alternately performed.
It is disclosed in Japanese Patent Laid-Open No. 6-194054. The heat storage body attached to such a heat storage type burner is usually composed of a lump made of ceramics or a metal (metal) carrier capable of storing a large amount of heat in a small volume. is there.

[0003]

In heating a material to be heated such as a steel piece as described above, iron powder, oxide powder, furnace wall (brick) powder, etc., adhering to the material to be heated is a regenerative burner. When exhaust gas is sucked during heat storage, it is sucked together with the exhaust gas by the metal heat storage body that constitutes the heat storage body, and clogging occurs in the metal heat storage body, causing the exhaust gas to pass through a portion of the metal heat storage body (heat storage body). Therefore, the amount of heat stored in the heat storage body decreases, and it becomes difficult to preheat combustion air sufficiently during combustion of the regenerative burner. It will decrease and worsen the fuel consumption rate. In addition, the life of the heat storage body becomes short and the cost becomes high, and the productivity is lowered due to the stop of the heating furnace due to the replacement of the heat storage body. Further, there is a problem that the durability is required to be improved because it contacts high temperature exhaust gas during heat storage. The present invention has been made in order to advantageously solve such a problem, reliably prevents clogging of the heat storage body, improves the heat storage function of the metal heat storage body, heat storage having high durability. The purpose of the present invention is to provide a heat storage body of a rotary burner.

[0004]

The feature of the present invention resides in that a large-volume coarse-grained ceramic layer is provided on the exhaust gas inlet side of a small-volume metal heat storage body, and a fine-grained ceramic layer is provided thereon. It is a heat storage body of a heat storage type burner characterized by doing.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the heat storage body of the heat storage type burner sucks the exhaust gas in the heating furnace to store the sensible heat of the exhaust gas during the heat storage, and is always in contact with the high temperature exhaust gas. Therefore, it is required to improve durability. On the other hand, it has been attempted to store heat with high efficiency in a heat storage body by contacting higher temperature exhaust gas. For example, a regenerative burner is installed in the preheating furnace of the heating furnace to perform regenerative alternating combustion heating, and a normal burner that does not have a tropical heat storage is provided in the heating zone and the soaking zone. The amount of combustion air supplied to the side heat storage burner is set near the maximum value of the constant heat storage burner capacity, and the combustion air ratio is increased when the combustion load decreases, and conversely when the combustion load increases. The ratio is reduced so that the amount of combustion exhaust gas is almost constant at all times. On the other hand, the exhaust gas suction amount for storing heat to the heat storage body of the heat storage side heat storage type burner also sucks the maximum capacity of the heat storage body (maximum capacity of the heat storage type burner) to store heat. When the combustion load decreases in this way, the combustion air ratio is increased to increase the amount of exhaust gas, so that the combustion load increases even when the combustion load of the combustion side regenerative burner decreases (near the maximum burner capacity). Make it almost the same as time. Therefore, when the combustion load decreases, mix with the exhaust gas that has increased due to the increase in the combustion air ratio and the hot exhaust gas that has flowed in from the heating zone and the soaking zone, and suck it into the heat storage side regenerative burner to store heat with high efficiency. Were developed by the present inventors.

In the heat storage of such a heat storage type burner, when the high temperature exhaust gas directly passes through the metal heat storage body,
Since there is a risk of exceeding the heat resistance limit of the metallic heat storage body and lowering the durability, in the present invention, the sensible heat of the exhaust gas is slightly removed by the large-volume coarse-grained ceramic layer arranged on the exhaust gas inlet side of the metal heat storage body. After heating, a large amount of heat is stored through a metal heat storage body that can store a large amount of heat in a small volume. That is, the function of the large-volume coarse-grained ceramic layer is to protect the metallic heat storage body from the high-temperature exhaust gas. In addition, at the time of combustion, the sensible heat slightly stored in the coarse-grained ceramic layer contributes to the heat storage of the metal heat storage body and the preheating of the combustion air.

Next, as the volume of the coarse grain ceramic layer,
The volume is larger than the volume of the metal heat storage body, that is, the ceramic has a lower thermal conductivity than the metal (metal heat storage body) and the heat storage amount is small, so that the sensible heat of the exhaust gas is removed little,
In order to remove the sensible heat of the high-temperature exhaust gas to a temperature that does not exceed the heat resistant temperature of the metal heat storage body, it is necessary to configure the coarse-grained ceramic layer to have a larger volume than the metal heat storage body volume. However, specifically, if the particle size is as described above, the metallic heat storage body volume 1: the coarse-grained ceramic layer volume 2 to 3.5 is surely used as the metal heat storage body as described above, though it slightly varies depending on the exhaust gas temperature. , Can be protected from high temperature exhaust gas. Also,
The particle size of the large-volume coarse-grained ceramics arranged on the exhaust gas inlet side of the metal heat storage body constituting the heat storage body is φ10 to φ2.
0 mm is sufficient.

The particle size of the fine-grained ceramics arranged in the upper layer of such a large-volume coarse-grained ceramic layer is as follows:
φ9 mm is suitable. That is, the function of the fine-grained ceramics is to capture dust such as iron powder contained in the exhaust gas. With the above-mentioned grain size, the layer thickness is 10 to 100 m.
The dust can be reliably captured with m.

[0009]

Embodiments of the present invention will now be described with reference to the drawings. In FIG. 1, on the exhaust gas inlet side A of the metal heat storage body 1, a coarse grain ceramic layer 2 having a volume larger than the volume of the metal heat storage body (metal carrier) 1 is arranged, and a fine grain ceramic layer 3 is provided on the upper side thereof.
Is arranged to form the heat storage body 4. Thus, at the time of combustion, combustion air is supplied from the exhaust gas outlet side B of the heat storage body 4, and the sensible heat stored from the metal heat storage body 1 and the coarse grain ceramic layer 2 is removed and preheated to be supplied to the tip of the burner 5. At the same time, fuel (gas generated in the coke oven, etc.) is supplied to the burner 5 and burned, and the inside of the heating furnace 6 is heated to heat a material to be heated (not shown). On the other hand, at the time of heat storage, the high temperature exhaust gas generated when the other heat storage type burner (not shown) is similarly burnt and heated is sucked from the exhaust gas inlet side A of the heat storage body 4 to remove dust in the exhaust gas into the fine grain ceramic layer. After being captured by 3, the coarse-grained ceramic layer 2 removes heat to a temperature lower than the heat resistant temperature of the metal heat storage body 1, the metal heat storage body 1 is allowed to pass through, and the metal heat storage body 1 stores a large amount of heat and exhausts the heat.

[0010]

According to the present invention, the dust in the exhaust gas can be captured to prevent clogging of the metal regenerator, and the durability of the metal regenerator can be maintained. The thermal efficiency of the heat storage body) can also be improved. Further, it is possible to obtain excellent effects such as preventing contact of the metal heat storage body with exhaust gas having a temperature higher than the heat resistant temperature, and improving the durability of the metal heat storage body while storing heat with high thermal efficiency.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing an embodiment of the present invention.

[Explanation of symbols]

 1 Metal heat storage body 2 Coarse grain ceramic layer 3 Fine grain ceramic layer 4 Heat storage body

Claims (1)

[Claims] 1. A regenerator for a regenerative burner, characterized in that a large volume coarse grain ceramic layer is disposed on the exhaust gas inlet side of a small volume metal regenerator, and a fine grain ceramic layer is disposed on top of it.