JP5949746B2 - Reactor simulating blast furnace cohesive zone - Google Patents

Description

  The present invention relates to a reactor simulating a blast furnace cohesive zone.

In recent years, due to soaring prices of steelmaking raw materials, reduction of the basic unit of coke used for blast furnaces is required.
However, when the coke is reduced, the coke that guarantees the air permeability in the furnace decreases, so that the airflow resistance increases in the blast furnace furnace.

In a general blast furnace, when the ore charged from the top of the furnace reaches a temperature at which softening starts, the ore is deformed while filling the voids by the weight of the raw material existing in the upper part. Therefore, in the lower part of the blast furnace, the ventilation resistance of the ore layer becomes very large, and an ore fusion layer in which gas hardly flows is formed. The air permeability of the cohesive zone, which is a zone including such an ore fusion layer, greatly affects the air permeability of the entire blast furnace, thereby limiting the productivity in the blast furnace.
Therefore, it is necessary to clarify the governing factors of gas permeability in the cohesive zone and to design an optimum layer structure.

  As an apparatus for evaluating gas permeability in the blast furnace cohesive zone, for example, a load softening apparatus shown in Patent Document 1 is known. This load softening device fills the crucible with blast furnace raw materials such as sintered ore, ore or coke, and distributes high-temperature gas from the lower part of the crucible while loading the load from the upper part of the sample layer to melt the ore in the blast furnace. It is a device that simulates behavior. By using this apparatus, it is possible to measure the gas ventilation resistance of the ore layer softened and shrunk.

  Further, an apparatus shown in Non-Patent Document 1 is known as an apparatus for measuring gas distribution to an ore layer and a coke layer in consideration of the presence of a coke layer. This device has a double pipe structure consisting of two tubes, a coke-filling tube and an ore-filling tube, and the inside of the ore-filling tube is the upper part of the ore layer, similar to the load softening device described above. The load is applied to simulate the softening and shrinkage behavior of the ore. Further, gas is distributed from the lower part of the double pipe, and gas is distributed to the coke layer of the outer pipe and the ore layer of the inner pipe according to the ventilation resistance of each layer.

JP-A-8-189926

Iron and Steel, Vol. 79, No. 8, 927-933

  As described above, the ventilation resistance of the ore layer is very large at the lower part of the blast furnace, an ore fusion layer in which almost no gas flows is formed, and the permeability of the fusion zone including such ore fusion layer is that of the entire blast furnace. It greatly affects the air permeability and controls the productivity in the blast furnace. Therefore, it is very important to clarify the gas permeability control factor in the cohesive zone and to design an optimum layer structure.

  Here, in order to accurately evaluate the ventilation resistance of the cohesive zone, it is necessary to reproduce the gas flow in the blast furnace. In general, the blast furnace cohesive zone is composed of two layers: an ore fusion layer with a very high ventilation resistance because of softening and shrinkage, and a coke layer with a low ventilation resistance without softening and shrinking. Therefore, the gas flowing through the cohesive zone flows sideways in the coke layer. Therefore, in order to simulate the gas flow in the blast furnace cohesive zone, it is necessary to reproduce the gas flow in the lateral direction.

The load softening device shown in the above-mentioned patent document 1 fills a crucible with blast furnace raw materials such as sintered ore, ore or coke, distributes high-temperature gas from the lower part of the crucible, and applies a load from the upper part of the sample layer. It is a device that simulates the ore melting behavior inside.
However, when this device is used, the gas is forced to flow through the ore fusion layer where gas is difficult to flow. Therefore, the air permeability evaluation of the entire layer structure when coke and ore are packed in layers Is impossible.

Moreover, the apparatus shown in Non-Patent Document 1 has a double pipe structure composed of two pipes, a pipe for filling coke and a pipe for filling ore, and the inside of the pipe for filling the ore is the same as the load softening device described above. The load is applied from the upper part of the ore layer to simulate the softening and shrinkage behavior of the ore. Gas is distributed from the lower part of the double pipe, and gas is distributed to the coke layer of the outer pipe and the ore layer of the inner pipe according to the ventilation resistance of each layer.
However, this device also has a coke packed bed and an ore packed bed independently, and the ore deforms in a direction perpendicular to the gas flow in the original cohesive zone, whereas it is horizontal to the gas flow. Since the ore layer is deformed, it cannot be said that the ventilation resistance of the whole packed layer of coke and ore can be accurately simulated.

  The present invention has been developed to solve the above-mentioned problems, and accurately simulates the ore melting behavior and gas flow in the blast furnace cohesive zone by accurately reproducing the gas flow in the vicinity of the cohesive zone. The purpose is to propose a reactor that simulates the blast furnace cohesive zone.

That is, the gist configuration of the present invention is as follows.
1. A sample heating furnace and a gas heating furnace having therein a sample filling container capable of filling iron ore and / or sintered ore and coke and / or coal are arranged in parallel, and the gas heated in the gas heating furnace A reaction apparatus simulating a blast furnace cohesive zone having a structure in which the sample packed bed in the sample packed container flows horizontally from the lateral direction.

2. A pedestal movable in the vertical direction is arranged on the upper part of the sample heating furnace, and a press plate is installed on the upper part of the sample packed bed in the sample filling container, and the pedestal and the press plate are connected with a connecting rod, 2. The reactor according to 1 above, wherein a constant load is applied to the sample packed bed by applying a load according to conditions on the upper portion of the pedestal.

3. It consists of measuring the temperature and pressure of the sample packed bed by drilling several holes in the holding plate installed on the top of the sample packed bed and inserting a tube connected to a thermocouple and a pressure gauge into the hole. 3. The reaction apparatus according to 1 or 2 above.

4). In the sample filling container, a cavity is provided in the lower part of the sample filling layer via a bottom plate, and a plurality of holes are provided in the bottom plate that separates the sample filling layer and the cavity, and generated from the holes during the sample reaction. 4. The reaction apparatus according to any one of 1 to 3, wherein the melt is dropped into the cavity so that the gas flow in the sample packed bed is not hindered by the melt.

  According to the present invention, it is possible to evaluate the ventilation resistance of the blast furnace cohesive zone according to the actual machine by flowing gas from the horizontal direction to the sample packed bed and applying a load to the sample packed bed in the vertical direction. It becomes.

It is a schematic diagram which shows the suitable example of the reaction apparatus according to this invention. It is a principal part detail drawing of FIG. It is a figure which shows the temperature conditions and gas conditions at the time of experimenting using this invention apparatus. It is a figure which compares and shows the measurement result about the pressure loss at the time of performing a simulation experiment on the conditions 1 and 2. It is a figure which compares and shows the measurement result about the pressure loss at the time of performing a simulation experiment on conditions 1 and 3. It is a figure which shows the relationship between Lc / Dc and ventilation resistance. It is a schematic diagram which shows the mode at the time of melting when (a) coke layer thickness is thick and (b) coke layer thickness is thin.

The present invention is an apparatus that reproduces the gas flow in the vicinity of the cohesive zone according to the actual machine in order to evaluate the gas permeability of the blast furnace cohesive zone. In general, the blast furnace cohesive zone is composed of two layers of an ore fusion layer that is melted and has a very high ventilation resistance and a coke layer that is not melted and has a low ventilation resistance. Accordingly, since the gas flowing in the vicinity flows laterally in the coke layer, it is necessary to reproduce the lateral gas flow in order to simulate the blast furnace cohesive zone.
For this reason, the present apparatus is configured such that gas flows from the horizontal direction to the sample packed bed and a load is applied to the ore in the vertical direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view of a preferred example of a reaction apparatus according to the present invention. In the figure, reference numeral 1 denotes a sample heating furnace, and the sample heating furnace 1 includes a sample filling container 2 and a heating device 3 therein. In the sample filling container 2, a sample filling layer 6 in which the coke layer 4 and the ore layer 5 are filled in layers is formed. The temperature of the sample packed layer 6 is controlled by the heating device 3.
Reference numeral 7 denotes a gas heating furnace, and the gas heating furnace 7 also includes a heating device 8 therein.
In addition, 9 is a gas mixer, 10 is a gas distribution pipe, 11 is a pressure gauge, 12 is a thermocouple, 13 is a holding plate, 14 is a pedestal, and 15 is a connecting rod. This connecting rod is made of graphite or metal. It is preferable that Reference numeral 16 denotes a load means, and a weight is used in this example. The weight 16 applies a load simulating the inside of the blast furnace to the sample packed layer 6.

  As shown in the figure, the apparatus of the present invention has the greatest feature in that the sample heating furnace 1 and the gas heating furnace 7 are arranged in parallel. As described above, because of the parallel arrangement, the gas heated in the gas heating furnace 7 enters the sample heating furnace 1 from the lateral direction. As a result, as shown in detail in FIG. Since the heated gas flows horizontally through the sample packed bed 6 in the sample packed container 1, the gas flow in the blast furnace fusion zone can be reproduced.

  In the apparatus of the present invention, by placing the weight 16 on the pedestal 14, it is possible to apply a constant load according to the operating conditions to the sample packed layer via the connecting rod 15 and the presser plate 13, and for this reason, In combination with the gas flow in the horizontal direction described above, it is possible to evaluate the ventilation resistance reflecting the layer structure in the blast furnace cohesive zone. In FIG. 2, reference numeral 17 indicates coke mixed in the ore layer 5.

  Further, in the apparatus of the present invention, several holes (not shown) are formed in the holding plate 13, and a tube connected to a thermocouple and a pressure gauge is inserted into the hole, thereby measuring the temperature and pressure of the sample packed bed 6. Can do. It is preferable that the number of holes opened in the presser plate 13 is about 4 to 8.

  In addition, in the apparatus of the present invention, a cavity 18 is provided in the lower part of the sample packing layer 6, and a plurality of holes 20 are provided in the bottom plate 19 that separates the sample packing layer 6 and the cavity 18. The melt produced therein can be dropped into the cavity, thereby eliminating the adverse effect that the gas flow in the sample packed bed 6 is hindered by the melt. The size of the hole 20 provided in the bottom plate 19 is preferably about 3 to 8 mm, which is smaller than the sample. In addition, the melt dripped into the cavity 18 is indicated by reference numeral 21 in FIG.

An experiment simulating a blast furnace cohesive zone was conducted using the above reactor.
Table 1 shows the raw material conditions when the experiment was conducted.

Condition 1 simulates when the coke ratio in the blast furnace is equivalent to 320 kg / t, and Condition 2 simulates the case where the coke ratio in the blast furnace is equivalent to 160 kg / t. Condition 3 is a case where a coke ratio in a blast furnace corresponding to 320 kg / t is mixed with a coke ratio equivalent to 160 kg into the ore layer.
Then, by comparing the condition 1 and the condition 2, the increase in the cohesive zone pressure loss when the coke ratio was decreased was investigated.
Further, by comparing the condition 1 and the condition 3, the effect of reducing the pressure loss when coke was mixed into the ore layer was investigated.

  3 (a) and 3 (b) show temperature conditions and gas conditions when an experiment is performed using the apparatus of the present invention. All the experiments were conducted at the same level.

FIG. 4 shows a comparison of investigation results on pressure loss when a simulation experiment is performed under conditions 1 and 2.
As shown in the figure, it can be seen that when the coke ratio is 160 kg / t (Condition 2), the pressure loss is greatly increased compared to the coke ratio of 320 kg / t (Condition 1). This makes it possible to measure the increase in cohesive zone pressure loss when the coke ratio is reduced.

FIG. 5 shows a comparison of investigation results on pressure loss when a simulation experiment is performed under conditions 1 and 3.
In this case, comparing condition 1 and condition 3, it can be seen that in condition 3, the pressure loss is reduced particularly in the high temperature range, and this makes it possible to measure the effect of reducing the cohesive zone pressure loss during coke mixing. It becomes.

  Next, Table 2 shows the experimental conditions when the cohesive zone ventilation resistance was measured using the above-described reactor.

  As shown in the table, the experiment was conducted by changing the thickness of the coke layer and the ore layer. Further, when the layer thickness was changed, the number of layers was changed so that the total value of the (coke layer / ore layer) layer thickness in the initial packed bed was constant. Lc represents the coke layer thickness, and Dc represents the coke particle size.

FIG. 6 shows the measurement results of the airflow resistance of the sample layer at 1400 ° C. in terms of the relationship between Lc / Dc and airflow resistance.
According to the figure, it can be seen that when Lc / Dc is 2 or less, the ventilation resistance increases rapidly.

Furthermore, the schematic diagram at the time of a fusion | melting is shown in FIG. FIG. 7A shows a state in which the coke layer thickness is thick, and FIG. 7B shows a state in which the coke layer thickness is thin.
As is clear from the figure, when the coke layer thickness is thinner than when the coke layer thickness is thick, the number of interfaces between the molten ore layer and the coke layer increases. Since the melt enters the coke layer from each interface, when the coke layer is thin, the thickness of the intrusion layer of the molten ore increases. Therefore, when the coke layer is thinned, the coke layer in which gas can easily flow is reduced, and the ventilation resistance is increased.
In particular, when Lc / Dc is 2 or less, the coke layer has a layer thickness of 2 or less coke particles, and in the portion where only one coke exists, this coke is wrapped in the melt from above and below, so this portion As a result, the coke layer where gas easily flows is blocked. Therefore, it is considered that the ventilation resistance suddenly increased when Lc / Dc was 2 or less.

Such a phenomenon is thought to have occurred in the load softening test apparatus that has been used to measure the airflow resistance of the conventional cohesive zone, but the load softening test apparatus measures the airflow resistance in the vertical direction of the sample layer. Since the thickness of the molten ore layer is larger than the melt intrusion layer thickness, it is difficult to isolate the influence of the melt intrusion layer thickness on the airflow resistance.
On the other hand, the ventilation resistance measured by the apparatus according to the present invention depends on the thickness of the coke layer through which gas can easily flow, so that the phenomenon that the melt penetrates into the coke layer and the ventilation resistance increases can be easily grasped. It becomes possible.

  From the above results, it is possible to measure the pressure loss of the fusion packed layer reflecting the layer structure by using the device of the present invention, and reflect the layer structure that could not be directly evaluated by this device. It has become possible to measure the cohesive zone pressure loss.

DESCRIPTION OF SYMBOLS 1 Sample heating furnace 2 Sample filling container 3 Heating device 4 Coke layer 5 Ore layer 6 Sample packed bed 7 Gas heating furnace 8 Heating device 9 Gas mixer
10 Gas distribution piping
11 Pressure gauge
12 Thermocouple
13 Presser plate
14 pedestal
15 Connecting rod
16 Load means (weight)
17 Mixed coke
18 cavity
19 Bottom plate
20 holes
21 Dropped melt

Claims (4)

  A sample heating furnace and a gas heating furnace having therein a sample filling container capable of filling iron ore and / or sintered ore and coke and / or coal are arranged in parallel, and the gas heated in the gas heating furnace A reaction apparatus simulating a blast furnace cohesive zone having a structure in which the sample packed bed in the sample packed container flows horizontally from the lateral direction.   A pedestal movable in the vertical direction is arranged on the upper part of the sample heating furnace, and a press plate is installed on the upper part of the sample packed bed in the sample filling container, and the pedestal and the press plate are connected with a connecting rod, The reaction apparatus according to claim 1, wherein a constant load is applied to the packed sample layer by applying a load according to conditions to the upper portion of the pedestal.   It consists of measuring the temperature and pressure of the sample packed bed by drilling several holes in the holding plate installed on the top of the sample packed bed and inserting a tube connected to a thermocouple and a pressure gauge into the hole. The reaction apparatus according to claim 1 or 2.   In the sample filling container, a cavity is provided in the lower part of the sample filling layer via a bottom plate, and a plurality of holes are provided in the bottom plate that separates the sample filling layer and the cavity, and generated from the holes during the sample reaction. The reactor according to any one of claims 1 to 3, wherein a gas flow in the sample packed bed is not hindered by the melt by dropping the melt into the cavity.

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