JP6922938B2 - Tar sludge discharge equipment and tar sludge discharge method - Google Patents

Description

The present invention relates to a tar sludge discharge device and a tar sludge discharge method contained in coke oven gas discharged from a coke oven.

Coal tar discharged from the coke oven together with coke oven gas contains coal. The coal content in coal tar is called tar slag. Since tar slag contains metal oxides in addition to solid coal, even if coal tar containing tar slag is processed into various tar products (for example, tar pitch) as it is, the required quality standard can be met. Unsatisfactory tar products cannot be obtained. Therefore, it is necessary to separate the tar slag from the coal tar recovered from the coke oven.

Sedimentation separation using a tar decanter device is widely used to separate tar slag from coal tar. In the tar decanter device, the tar slag separated from coal tar becomes a slurry (hereinafter referred to as "tar sludge") accompanied by coal tar and is deposited on the bottom of the tar decanter.

Patent Document 1 discloses a tar decanter device that scrapes up and collects tar sludge accumulated on the bottom of a tar decanter from the bottom by operating a scraper for a certain period of time on a regular basis.

Japanese Unexamined Patent Publication No. 2017-171836

In the conventional tar decanter device, the tar sludge accumulated on the bottom of the tar decanter is scraped out from the bottom with coal tar mixed in and collected by using a scraper. When it becomes thick, the density of the scraped tar sludge becomes excessive, and there is a problem that the discharge pipe for discharging the tar sludge is blocked. In addition, this blockage may deteriorate the quality of tar sludge.

Further, the tar sludge discharged from the tar decanter device is dried in a drying facility to form a solid material, and then charged into a coke oven as a raw material. If the density of tar sludge discharged from the tar decanter device is too low, the coal tar mixing ratio becomes high, the surface of the solid material becomes sticky, and a transfer abnormality occurs in the transfer process of transporting the solid material to the coke oven. There was also.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a tar sludge discharge device and a tar sludge discharge method capable of adjusting the density of the discharged tar sludge.

The features of the present invention for solving such a problem are as follows.
(1) A tar decanter that stores the cooling waste liquid obtained by cooling the coke oven gas and allows it to stand to separate tar sludge from the cooling waste liquid, a circulation pipe that circulates the tar sludge discharged from the tar decanter, and a circulation pipe. The circulation pipe has a discharge pipe for connecting the circulation pipe and the sludge tank and a control device, and the circulation pipe includes a pump for delivering the tar sludge, a densitometer for measuring the density of the tar sludge, and a circulation valve. And, the discharge pipe has a discharge valve, and the control device controls the operation of the circulation valve and the discharge valve by using the density data output from the densitometer. Discharge equipment.
(2) The tar sludge discharge equipment according to (1), which is provided in the circulation pipe in the order of the density meter, the connection portion with the discharge pipe, and the circulation valve from the upstream side in the circulation direction of the tar sludge.
(3) The circulation pipe further has a flow meter for measuring the flow rate of the tar sludge.
The tar sludge discharge equipment according to (1) or (2), wherein the pump is an inverter pump.
(4) The tar sludge discharge facility according to any one of (1) to (3), wherein the pump has a function of crushing the tar sludge.
(5) The tar sludge discharge facility according to any one of (1) to (4), wherein the circulation pipe further includes a steam purge facility for steam purging the circulation pipe.
(6) In the tar sludge discharge method using the tar sludge discharge facility according to any one of (1) to (5), when the density of the tar sludge is lower than a predetermined density range. Is a tar sludge discharge method in which the circulation valve is opened and the discharge valve is closed, and when the density of the tar sludge is within a predetermined density range, the discharge valve is opened and the circulation valve is closed.
(7) When switching between opening and closing of the discharge valve and the circulation valve, both the discharge valve and the circulation valve are opened and then either the discharge valve or the circulation valve is closed (6). The tar sludge discharge method described in.
(8) The tar sludge discharge method according to (6) or (7), wherein an alarm is issued from the control device when the density of the tar sludge exceeds a predetermined density range.

By using the tar sludge discharge device of the present invention, tar sludge adjusted to a predetermined density is discharged. As a result, it is possible to prevent the tar sludge having an excessively high density and an excessively low density from being discharged to the discharge pipe, and it is possible to suppress the blockage of the discharge pipe.

It is a schematic diagram which shows an example of the tar sludge discharge equipment 10 which concerns on this embodiment. It is a flow chart which shows an example of the control by a control device 24. It is a control timing chart figure of the tar sludge discharge equipment 10.

The present invention will be described through embodiments of the present invention. FIG. 1 is a schematic view showing an example of a tar sludge discharge facility 10 according to the present embodiment. The tar sludge discharge facility 10 includes a tar decanter 12, a circulation pipe 14, a discharge pipe 40, and a control device 24. The tar decanter 12 has a scraper at the bottom and stores a cooling effluent that cools the coke oven gas discharged from the coke oven. By being allowed to stand in the tar decanter 12, the cooling effluent is separated into the upper layer of ammonia water, the middle layer of coal tar, and the lower layer of tar sludge.

The tar sludge accumulated in the lower layer is scraped off by the scraper and discharged to the circulation pipe 14. The circulation pipe 14 includes a pump 16, a mass flow meter 18, a circulation valve 20, and a steam purge facility 22. The pump 16 is an inverter pump, and tar sludge mixed with coal tar is sent out at a predetermined flow rate in the direction of arrow 17, and is circulated in the pipe or discharged to a sludge tank.

The pump 16 preferably has a function of crushing tar sludge. By using a pump having a function of crushing tar sludge, tar sludge of a predetermined size can be mixed with coal tar and sent out. As a result, the local increase in the density of tar sludge in the circulation pipe 14 and the discharge pipe 40 is suppressed, and the operation using the tar sludge discharge facility 10 can be stabilized.

As the mass flow meter 18, it is preferable to use a device having the functions of a densitometer and a flow meter, such as a Koriori type mass flow meter capable of measuring the density and flow rate of tar sludge, but the density is not limited to this. It suffices if it has a measurable function. The mass flow meter 18 outputs tar sludge density data to the control device 24. Further, as shown in the present embodiment, the flow rate data of the tar sludge is output from the mass flow meter 18 to the pump 16, and the pump 16 is sent out so that the circulating flow rate of the tar sludge from the pump 16 becomes a predetermined flow rate. It is preferable to control the amount.

The circulation valve 20 opens and closes the circulation pipe 14 in response to a control signal from the control device 24. The circulation valve 20 is, for example, a valve with an actuator. The steam purge equipment 22 has a steam pressure valve 32, a steam drain valve 34, and a steam purge valve 36. The steam purging equipment 22 steam purges the inside of the circulation pipe 14 with the steam 30 when the circulation pipe 14 is closed by the circulation valve 20. By steam purging the inside of the circulation pipe 14, the tar sludge can be sent to the tar decanter as it is, and as a result, the circulation pipe 14 is closed and the solid content of the tar sludge accumulated in the circulation pipe 14 is settled. By accumulating, it is possible to prevent the solid content of tar sludge from sticking to the circulation pipe 14 and clogging.

The discharge pipe 40 connects the circulation pipe 14 and the sludge tank 50. The discharge pipe 40 has a discharge valve 42. The discharge valve 42 opens and closes the discharge pipe 40 in response to a control signal from the control device 24. The discharge valve 42 is, for example, a valve with an actuator.

The control device 24 controls the operation of the circulation valve 20 and the discharge valve 42 by using the density data output from the mass flow meter 18. The control device 24 receives density data from the mass flow meter 18 at predetermined intervals, for example, at intervals of 1 second, and controls the operations of the circulation valve 20 and the discharge valve 42 using the density data. The control device 24 is, for example, a computer including a CPU and a storage device, and the storage device stores in advance a program necessary for controlling the circulation valve 20 and the discharge valve 42 and data used for the program. By executing these programs in the CPU of the control device 24, the circulation valve 20 and the discharge valve 42 are controlled.

The density range of tar sludge used to control the operation of the circulation valve 20 and the discharge valve 42 is also predetermined and stored in the storage device. The upper limit Hi of the tar sludge density range is determined from the viewpoint of the density that does not cause pipe blockage. Further, the lower limit Lo of the density range of tar sludge is determined from the viewpoint of a density that does not cause a transfer abnormality in transportation using a conveyor due to the sticky surface of the solid material when the tar sludge is dried to form a solid material. Be done.

When the density data output from the mass flow meter 18 becomes lower than the predetermined density range, the control device 24 opens the circulation valve 20 and closes the discharge valve 42. As a result, tar sludge having a density lower than the density range is returned to the tar decanter 12 and concentrated. The concentrated and densed tar sludge is discharged from the tar decanter 12 to the circulation pipe 14 again.

The control device 24 opens the discharge valve 42 and closes the circulation valve 20 when the density data output from the mass flow meter 18 is within a predetermined density range. As a result, the tar sludge adjusted within a predetermined density range can be discharged from the discharge pipe 40, and as a result, the pipe blockage and the transfer abnormality of the solid material obtained by drying the tar sludge are suppressed.

Further, the control device 24 closes one of the discharge valve 42 and the circulation valve 20 after opening both the discharge valve 42 and the circulation valve 20 when switching between opening and closing of the discharge valve 42 and the circulation valve 20. Is preferable. Specifically, when switching from the open state of the discharge valve 42 and the closed state of the circulation valve 20 to the closed state of the discharge valve 42 and the open state of the circulation valve 20, the control device 24 first sets the control device 24. After opening both the discharge valve 42 and the circulation valve 20, the discharge valve 42 is closed. As a result, it is possible to suppress an increase in pressure in the circulation pipe 14 and the discharge pipe 40.

Further, the control device 24 may issue an alarm when the density data output from the mass flow meter 18 deviates from a predetermined density range. As an alarm, it is preferable to use an alarm sound from a speaker, lighting of a warning light, a warning display on an operation panel, or the like. As a result, the user can recognize that the tar sludge density is out of the predetermined density range and can take prompt measures. Therefore, due to fluctuations in the feed amount of the cooling waste liquid, changes in the coke raw material, etc. Even if some kind of trouble occurs and the density of tar sludge suddenly increases, it is possible to prevent the pipe blockage due to the high density tar sludge, and even if the pipe blockage occurs, the damage is reduced. can. In addition, instead of the alarm, or together with the alarm, the control device 24 may display a display device such as a display indicating that the density of the tar sludge is out of the predetermined density range together with the density of the tar sludge.

FIG. 2 is a flow chart showing an example of control by the control device 24. The control flow of the tar sludge discharge equipment 10 by the control device 24 will be described with reference to FIG. When the control device 24 is activated, the control device 24 receives density data from the mass flow meter 18 (S1). The control device 24 determines whether or not the received density data is equal to or higher than the preset lower limit LL (S2). If it is determined that the density data is less than the lower limit LL (S2: No), an alarm is issued to notify the operator or the supervisor (S12), and the process is stopped. If the density data is less than the lower limit LL, it takes a long time to reach the density above the lower limit Lo even if the tar decanter 12 is circulated, so it is necessary to take another measure to increase the density of tar sludge. Because.

On the other hand, when it is determined in step S2 that the density data is equal to or higher than the lower limit LL (S2: Yes), the control device 24 determines whether or not the received density data is equal to or higher than the preset lower limit Lo (S3). When it is determined that the density data is equal to or higher than the lower limit Lo (S3: Yes), the control device 24 continues to determine whether or not the density data is equal to or lower than the upper limit Hi (S4). When it is determined that the density data is equal to or lower than the upper limit Hi (S4: Yes), that is, when the density data is equal to or higher than the lower limit Lo and equal to or lower than the upper limit Hi, the control device 24 temporarily connects the circulation valve 20 and the discharge valve 42. An instruction to open each is output (S5), and a sudden rise in pressure in the pipe due to subsequent valve switching is suppressed.

Subsequently, the control device 24 outputs an instruction to close the circulation valve 20 and open the discharge valve 42 (S6). As a result, the circulation valve 20 is closed, the discharge valve 42 is opened, and the tar sludge from the tar decanter 12 is discharged from the discharge pipe 40 to the sludge tank 50 (T1). After that, the control device 24 returns the process to step S1, receives the density data from the mass flow meter 18 again, and executes the processes after step S2.

On the other hand, when it is determined in step S3 that the density data is less than the lower limit Lo (S3: No), the control device 24 once outputs an instruction to open the circulation valve 20 and the discharge valve 42, respectively (S7). ), Suppress the sudden rise in pressure in the pipe due to subsequent valve switching.

Subsequently, the control device 24 outputs an instruction to open the circulation valve 20 and close the discharge valve 42 (S8). As a result, the circulation valve 20 is opened, the discharge valve 42 is closed, and the tar sludge from the tar decanter 12 is circulated again from the circulation pipe 40 to the tar decanter 12 (T2). After that, the control device 24 returns the process to step S1, receives the density data from the mass flow meter 18 again, and executes the processes after step S2.

When it is determined in step S4 that the density data exceeds the upper limit Hi (S4: No), the control device 24 further determines whether or not the density data exceeds the upper limit HH (S9). When it is determined that the density data is equal to or less than the upper limit HH (S9: Yes), the control device 24 outputs an instruction to open the circulation valve 20 and close the discharge valve 42 (S10), and the steam pressure valve 32 and An instruction to open the steam purge valve 36 is output (S11), and the circulation pipe 40 is washed with steam (T3). After that, the control device 24 returns the process to S1, receives the density data from the mass flow meter 18 again, and executes the processes after step S2.

If it is determined in step S9 that the density data exceeds the upper limit HH (S9: No), an alarm is issued to notify the operator or the supervisor (S12), the process is stopped, and the tar sludge discharge facility is stopped. Take measures such as manually cleaning the pipes. The process shown in FIG. 2 is stopped when an input for terminating the control of the tar sludge discharge facility 10 is received from the operator.

In this way, the control device 24 controls the tar sludge discharge facility 10, so that the tar sludge adjusted to a predetermined density is discharged to the sludge tank 50.

Further, in the tar sludge discharge facility 10 according to the present embodiment, an example in which the mass flow meter 18, the connection portion with the discharge pipe 40, and the circulation valve 20 are provided in this order from the upstream side in the circulation direction is shown, but it is not necessarily in this order. It does not have to be provided. However, if it is not in this order, it is necessary to provide a mass flow meter 18 on both the discharge pipe 40 and the circulation pipe 14. Further, by providing the mass flow meter 18, the connection portion with the discharge pipe 40, and the circulation valve 20 in this order from the upstream side in the circulation direction described above, the density measured by the mass flow meter 18 and the discharged tar sludge can be measured. It is more preferable because the density difference from the density can be reduced.

Further, in the tar sludge discharge facility 10 according to the present embodiment, the flow rate of the tar sludge is measured by the mass flow meter 18 using the inverter pump and the mass flow meter 18, and the circulating flow rate of the tar sludge is measured using the flow data. Although an example of controlling is shown, it is not always necessary to control the circulation flow rate of tar sludge. However, if the circulation flow rate is not controlled, the flow velocity of the tar sludge in the circulation pipe becomes too high, and the pipe wear may be accelerated. Therefore, it is more preferable to control the circulating flow rate of tar sludge by using an inverter pump and a mass flow meter 18.

Further, in the tar sludge discharge facility 10 according to the present embodiment, an example in which the steam purge facility 22 is provided in the circulation pipe 14 is shown, but the steam purge facility 22 may not be provided. However, it is preferable to provide a steam purge facility 22, which causes tar sludge to be discharged from the discharge pipe 40 for a long period of time, and the solid content of the tar sludge staying in the circulation pipe 14 for a long period of time is accumulated, and the solid content is accumulated in the circulation pipe. It is possible to prevent the circulation pipe from being blocked by sticking to 14.

FIG. 3 is a control timing chart of the tar sludge discharge facility 10. When the density of tar sludge was not less than the lower limit Lo and not more than the upper limit Hi, the discharge valve 42 was opened and the circulation valve 20 was controlled to be closed. Further, when switching between the discharge valve 42 and the circulation valve 20, in order to prevent an abnormal rise in the pressure of the circulation pipe 14 and the discharge pipe 40, both the discharge valve 42 and the circulation valve 20 were controlled to be opened at the same time (FIG. 3). * Department). In addition, the opening and closing times of the steam pressure valve 32, the steam drain valve 34, and the steam purge valve 36 were also controlled by setting a timer.

In the control timing chart shown in FIG. 3, by controlling the opening and closing of the discharge valve 42, the circulation valve 20, the steam pressure valve 32, the steam drain valve 34, and the steam purge valve 36, the predetermined lower limit Lo or more and the upper limit Hi or less The tar sludge adjusted to the density could be discharged to the sludge tank 50.

10 Tar sludge discharge equipment 12 Tar decanter 14 Circulation piping 16 Pump 17 Arrow 18 Mass flow meter 20 Circulation valve 22 Steam purge equipment 24 Control device 30 Steam 32 Steam pressure valve 34 Steam drain valve 36 Steam purge valve 40 Discharge pipe 42 Discharge valve 50 Sludge tank

Claims (8)

A tar decanter that separates tar sludge from the cooling effluent by accommodating the cooling effluent that cooled the coke oven gas and allowing it to stand still.
A circulation pipe that circulates the tar sludge discharged from the tar decanter, and
The discharge pipe that connects the circulation pipe and the sludge tank,
With a control device,
The circulation pipe has a pump for delivering the tar sludge, a densitometer for measuring the density of the tar sludge, and a circulation valve.
The discharge pipe has a discharge valve and has a discharge valve.
The control device is a tar sludge discharge facility that controls the operation of the circulation valve and the discharge valve by using the density data output from the density meter. The tar sludge discharge facility according to claim 1, wherein the tar sludge discharge facility is provided in the circulation pipe in the order of the density meter, the connection portion with the discharge pipe, and the circulation valve from the upstream side in the circulation direction of the tar sludge. The circulation pipe further includes a flow meter for measuring the flow rate of the tar sludge.
The tar sludge discharge equipment according to claim 1 or 2, wherein the pump is an inverter pump. The tar sludge discharge facility according to any one of claims 1 to 3, wherein the pump has a function of crushing the tar sludge. The tar sludge discharge facility according to any one of claims 1 to 4, wherein the circulation pipe further includes a steam purge facility for steam purging the circulation pipe. A tar sludge discharge method using the tar sludge discharge facility according to any one of claims 1 to 5.
When the density of the tar sludge is lower than the predetermined density range, the circulation valve is opened and the discharge valve is closed.
A tar sludge discharge method in which the discharge valve is opened and the circulation valve is closed when the density of the tar sludge is within a predetermined density range. The sixth aspect of claim 6, wherein when switching between opening and closing of the discharge valve and the circulation valve, both the discharge valve and the circulation valve are opened and then either the discharge valve or the circulation valve is closed. Tar sludge discharge method. The tar sludge discharge method according to claim 6 or 7, wherein an alarm is issued from the control device when the density of the tar sludge exceeds a predetermined density range.

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