JP5487593B2 - Coke oven flue dust collector startup method - Google Patents

Description

  The present invention relates to a method for starting a coke oven flue dust collector.

  If the sealing performance of the brick wall that separates the carbonization chamber and the heating chamber in the coke oven deteriorates due to aging of the coke oven, a part of the combustible gas volatilized from the coal charged in the carbonization chamber is heated. Leaked into the chamber and burned incompletely in the heating chamber, generating soot. When dust such as soot is contained in the exhaust gas discharged from the coke oven, the exhaust gas becomes black smoke. From the viewpoint of environmental problems such as pollution, black smoke countermeasures are necessary. As a measure against the black smoke, conventionally, a method of removing black smoke by installing an electric dust collector or a bag filter in a flue portion from a coke oven to a chimney has been adopted (for example, Patent Document 1).

Since the dust collector is installed as a measure against black smoke accompanying deterioration of the existing coke oven, there may be a case where the installation space for the dust collector cannot be secured near the coke oven. In such a case, the flue pipe that leads the exhaust gas from the coke oven to the chimney through the dust collector becomes long. When the flue pipe becomes long, the exhaust gas temperature decreases before being introduced into the chimney, and the gas specific gravity increases. As a result, the draft force of the chimney decreases and a gas is not quickly discharged from the chimney. The gas that is not discharged from the chimney circulates in the flue pipe and raises the flue pressure. As a result of the flue pressure exceeding the operating pressure of the coke oven, the dust collector cannot be started up. .
JP 56-104992 A

  The object of the present invention is to solve the above problems, and even when the flue pipe leading the exhaust gas from the coke oven to the chimney through the dust collector becomes long, the flue pressure does not exceed the operating pressure of the coke oven, It is to provide a method for starting a flue dust collector that can be started stably.

In order to solve the above-mentioned problems, a method for starting a flue dust collector for a coke oven according to the present invention includes a first flue for guiding exhaust gas from a coke oven to a chimney without going through the dust collector, and an exhaust gas from the coke oven to the dust collector. Of a flue dust collector used in a coke oven having a second flue leading to the chimney via the first flue, wherein the exhaust gas flow rate from the coke oven to the chimney is adjusted in the first flue The second flue is equipped with a dust collector adjustment valve that adjusts the exhaust gas flow rate from the dust collector to the chimney, and when the flue dust collector starts up, the flue adjustment valve is opened, As the exhaust gas temperature rises on the dust collector inlet side, the dust collector adjustment valve is gradually opened from the closed state, and the exhaust gas passing through the first flue and the exhaust gas passing through the second flue merge at the lower part of the chimney It was the combined gas temperature, of the chimney de By maintaining the exhaust gas temperature shift pressure is ensured, and is characterized in increasing Rukoto up the flue dust collector.

The invention according to claim 2 is a method for starting up a flue dust collector for a coke oven according to claim 1, wherein the exhaust gas temperature T ₀ at the inlet side of the dust collector is used as an index, and when T ₀ reaches a certain temperature, The dust collector adjusting valve is opened in stages.

  When there is no space for installing a dust collector near the coke oven, the second flue pipe leading from the coke oven to the chimney via the dust collector becomes long. As a result, only the exhaust gas temperature via the second flue pipe at the beginning of the dust collector does not provide sufficient chimney draft pressure, and the flue pressure rises above the operating pressure, causing the dust collector to start up. It is a technology that makes it possible to start up a dust collector by applying it when it is difficult. When starting up the dust collector, the temperature inside the dust collector and the second flue pipe is significantly lower than the exhaust gas temperature from the coke oven, so the exhaust gas from the coke oven passes through the second flue pipe. And until it reaches the lower part of the chimney, the heat energy is absorbed and the exhaust gas temperature falls. According to the present invention, exhaust gas is introduced from each of the first flue for introducing high-temperature exhaust gas directly from the coke oven to the chimney and the second flue for introducing exhaust gas from the coke oven to the chimney via a dust collector. In the initial start-up process when the temperature inside the dust collector and the temperature inside the second flue pipe are not sufficiently increased, the amount of exhaust gas passing through the first flue is restricted while limiting the amount of exhaust gas passing through the second flue. By setting the exhaust gas temperature that merges at the lower part of the chimney to a range where the draft pressure of the chimney is secured by the thermal energy that is possessed, the dust collector can be started up stably regardless of the length of the second flue pipe Made it possible to do.

  FIG. 1 shows an exhaust gas flow of a coke oven according to the dust collector startup method of the present invention. Here, the start-up of the dust collector refers to the formation of an exhaust gas flow path that passes from the coke oven to the chimney through the dust collector after a new dust collector is installed or maintenance work is performed on the dust collector. Say. In order to exhaust the exhaust gas from the chimney, a predetermined draft pressure as shown in Table 1 below is required. In order to obtain the draft pressure, the exhaust gas temperature at the lower part of the chimney is required to be higher than the predetermined temperature. .

  The dust collector will be installed later as a countermeasure against the black smoke of exhaust gas accompanying the aging of the coke oven. Therefore, the space for installing the dust collector in the vicinity of the coke oven is not always ensured. When the dust collector is installed at a place away from the coke oven, the pipe length of the flue 7 (referred to as the second flue in the present invention) for guiding the exhaust gas from the coke oven 1 to the chimney 3 via the dust collector 2 is In some cases, the length exceeds 100 m.

For example, when the pipe length is about 40 m, the start-up method is that after the dust collector 2 is started up with the flue adjustment valve 5 kept open, the dust collector adjustment valve 4 is opened about 20%, and the coke oven is opened. The exhaust gas discharged from the exhaust gas flows into the second flue 7. When the pipe length is about 40 m, as shown in FIG. 2, the exhaust gas temperature T ₀ on the dust collector 2 entrance side becomes 150 to 170 ° C. in about 15 minutes after the dust collector adjustment valve 4 is opened. The valve 4 is fully opened, the flue regulating valve 5 is closed, and the start-up is completed.

On the other hand, when the pipe length is 100 m or more, after starting the dust collector 2 with the flue adjusting valve 5 kept open as described above, the dust collector adjusting valve 4 is opened by about 20%, and the coke oven is opened. When exhaust gas discharged from the exhaust gas flows into the second flue 7, the exhaust gas temperature decreases in the process of passing through a pipe of 100 m or more, and the exhaust gas temperature T _{1 at the} lower part of the chimney is necessary to obtain the chimney draft pressure. Therefore, the exhaust gas is not discharged from the chimney, the flue pressure rises, and the dust collector cannot be started up safely.

The present invention is a technique related to a dust collector startup method applied in such a case. In the present invention, first, after starting the dust collector 2 with the flue adjusting valve 5 kept open, the dust collector adjusting valve 4 is opened by about 2%, and the high temperature exhaust gas discharged from the coke oven is discharged. While flowing into the second flue 7, the pipe and the dust collector are heated. On the other hand, since the open state of the flue adjusting valve 5 is also maintained, the high-temperature (T ₂ ) exhaust gas flowing from the first flue also flows into the lower part of the chimney. Here, by suppressing the opening degree of the dust collector adjusting valve 4 to be lower than the opening degree (100%) of the flue adjusting valve 5, it flows from the first flue that occupies the ratio of the exhaust gas flowing into the lower part of the chimney. The ratio of the high-temperature (T ₂ ) exhaust gas can be increased, and the combined exhaust gas temperature at the lower part of the chimney can be maintained at the exhaust gas temperature necessary for obtaining the chimney draft pressure.
Here, the combined exhaust gas temperature refers to a temperature defined by the following equation.
{(T ₂ × exhaust amount via first flue) + (T ₁ × exhaust amount via second flue)} ÷ (exhaust amount via first flue + second flue amount) Exhaust gas amount)

  In the present invention, the combined exhaust gas temperature at the lower part of the chimney is maintained at the exhaust gas temperature necessary for obtaining the chimney draft pressure in this way, regardless of the length of the second flue pipe. The exhaust gas introduced into the lower part of the chimney via the second flue pipe can be discharged from the chimney, and the problem of the flue pressure rise due to the low temperature exhaust gas can be avoided.

The exhaust gas temperature T ₀ on the dust collector 2 entry side rises with time in the process of starting the dust collector 2 and flowing the exhaust gas from the coke oven 1 having high thermal energy to the second flue 7. I will do it. In the present invention, the exhaust gas temperature T ₀ on the dust collector entrance side is used as an index, and each time T ₀ reaches a certain temperature, the opening degree of the dust collector adjustment valve 4 is gradually increased, and the exhaust gas temperature T ₀ on the dust collector entrance side is increased. After the temperature reaches 150 to 170 ° C., the dust collector adjusting valve 4 is fully opened, the flue adjusting valve 5 is closed and the start-up is completed, so that the dust collector 2 can be started up stably.

  FIG. 4 shows the result of starting up the coke oven dust collector shown in FIG. 3 by adjusting the opening degree of the dust collector adjusting valve 4 stepwise according to the sequence shown in Table 2 below.

  As shown in FIG. 4, according to the method of the present invention, even a dust collector having a pipe length that has been difficult to start up by the conventional start-up method can be started up stably.

Exhaust gas flow diagram in the dust collector startup method of the present invention Relationship diagram of start-up time, T ₀ temperature, and flue pressure when the dust collector can be started up using the conventional method Example of dust collector arrangement having pipe length to which the present invention is applied FIG. 3 is a relationship diagram of the start-up time, T ₀ temperature, and flue pressure when the present invention is applied to the embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coke oven 2 Dust collector 3 Chimney 4 Dust collector adjustment valve 5 Flue adjustment valve 6 First flue 7 Second flue 8 Adjustment valve

Claims (2)

A flue dust collector used in a coke oven having a first flue that leads exhaust gas from the coke oven to the chimney without going through the dust collector and a second flue that leads the exhaust gas from the coke oven to the chimney via the dust collector A startup method,
The first flue is equipped with a flue control valve that adjusts the exhaust gas flow rate from the coke oven to the chimney,
The second flue is equipped with a dust collector adjustment valve that adjusts the exhaust gas flow rate from the dust collector to the chimney,
At the start of flue dust collector start-up, the flue adjustment valve is opened, and the dust collector adjustment valve is gradually opened from the closed state as the exhaust gas temperature rises on the dust collector inlet side.
By maintaining the combined gas temperature of the exhaust gas passing through the first flue and the exhaust gas passing through the second flue at the lower part of the chimney at the exhaust gas temperature at which the draft pressure of the chimney is secured, flue raising of dust collector characterized by raising Rukoto up the road dust collector. Wherein as an indicator of exhaust gas temperature T ₀ of the dust collector entry side, for each arrival T ₀ is a constant temperature, start-up of the flue dust collector of claim 1, wherein the gradually and stepwise opened the dust collector adjustment valve Method.

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