JPS62242706A - Method of controlling water level of converter boiler drum - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to a method for controlling the water level of a converter boiler drum provided in a converter.

``Prior Art'' Generally, converters for refining copper and iron emit high-temperature and toxic exhaust gas. As an example, the exhaust gas from a converter for copper refining has a high temperature of about 100° C., and contains 11 tons of sulfurous acid (S O t) gas. For this reason, the temperature of the exhaust gas from the converter is lowered,
Additionally, equipment for pollution treatment is required attached to the converter.

Conventionally, a converter boiler is attached to a converter for the above-mentioned pollution treatment and the like. FIG. 6 is a diagram showing the conventional converter boiler. In FIG. 6, the symbol B
is a converter boiler, and this converter boiler B is a boiler! 3, a drum I that stores circulating water and steam, and a water pipe 2 that recovers heat from the high temperature of the exhaust gas from the converter.
, a circulation pump 3 that forcibly circulates water through the water pipe 2, a steam line 4 that supplies steam from the drum 1 to a turbine (not shown), and a water purifier (not shown) from the turbine (iii). The drum 1 is generally composed of a water supply line 5 for supplying water to the drum 1, and a drainage line 6 for discharging water from the drum 1. A flow meter 7 and a check valve 8 are attached to the steam line 4 in the middle thereof. Like the steam line 4, the water supply line 5 is equipped with a flow meter 7 and
A valve 9 is attached in the middle. A blow valve IO is attached to the drainage line 6 in the middle thereof.

As shown in FIG. 1, for example, the converter boiler B has five drums 1, I, . It has been merged into the book.

The converter boiler B is started by supplying water in advance into its drum 1, and forcing the circulation pump 3 to circulate this water through the water pipes 2. At this time, the drums IS I, ... of the converter boiler B are connected to the boiler II, for example, as in the above example.
3, 5 drums 1, 1, . . . are set up, and 3 cans are in operation. When the converter is in operation, the high heat of the exhaust gas discharged from the converter passes through the water pipe 2.
The temperature is reduced to 250℃ due to the water that circulates inside.
The exhaust gas whose temperature has been lowered to ~300°C is collected by a Cottrell or the like and then transferred to a Mi acid factory, where it is recovered and reused as sulfuric acid. on the other hand,
The water that has recovered the heat from the exhaust gas is further forcibly circulated between the water pipe 2 and the drum 1 by the circulation pump 3 while a part of it becomes steam due to the rise in temperature. When the pressure within the drum 1 has increased to a certain extent, the steam stored in the drum 1 passes through the steam line 4 to the turbine, and its energy is reused as a power source. Thereafter, the steam that has been turned into water as a result of being cooled by the turbine is fed into the drum l again via the water supply line 5 via the water purifier. In addition, when the converter is inactive, no exhaust gas is discharged from the converter, but the next time exhaust gas is discharged from the converter, the temperature of the water circulating in the water pipe 2 will be lower than the dew point temperature of sulfuric acid. If the temperature drops, sulfuric acid may condense on the surface of the water pipe 2, so for the purpose of maintaining this water temperature constant and preventing water leakage from the valve 9 of the water supply line 5, a pipe (not shown) is used. High pressure steam is blown into the drum l. During this time, water is forcibly circulated between the drum 1 and the water pipe 2 by the circulation pump 3.

With the above configuration, the converter boiler B attached to the converter facilitates the post-treatment of pollution treatment by lowering the temperature of the exhaust gas discharged from the converter, and also utilizes the energy contained in the exhaust gas. enable effective reuse.

Here, in the drum 1 of the converter boiler B, the water expands and contracts due to the rise and fall of the water temperature in the drum 1, and at the same time, the drum 111. The water level fluctuates due to reasons such as pressure interference through the steam line 4 due to the operation of the steam line 4. In particular, this phenomenon is noticeable during both operating and idle states of the converter. If the water level in the drum 1 fluctuates abnormally, for example if the water level drops abnormally, assuming an extreme situation, the water will not circulate in the water pipe 2, and the exhaust gas from the converter will cause the water pipe 2 to This results in overheating and damage to the water pipe 2. Furthermore, if the water level in the drum 1 rises abnormally, a phenomenon (carryover) occurs in which water is mixed into the steam supplied to the turbine via the steam line 4, resulting in damage to the turbine. Become. In particular, when the water level rises when the converter is not in operation, in addition to the above-mentioned phenomenon, the rise in the water level inside the drum 1 due to the expansion of water when the converter is in operation may exceed the permissible range of the drum 1.

°For the above reasons, the water level in drum l of converter boiler B is controlled in six ways according to the operating status of each converter, taking into account the expansion of water during converter operation and converter down time. It is necessary to FIG. 2 is a diagram showing a method of controlling the water level in the drum l of a conventional converter boiler B. In Figure 2,
Reference numeral 11 is a water level gauge that detects the water level in the drum L, reference numeral I
2 is a drum level indicator that indicates the current water level in the drum 1 based on the input signal from the water level indicator 11, and issues an alarm signal when the water level in the drum 1 exceeds the upper and lower limits of the appropriate range; Reference numeral I3 indicates a computing unit that calculates the water supply amount based on the signal from the flow meter 7 provided in the steam line 4 and the signal from the drum level indicator 12, and reference numeral 14 indicates the signal from this computing unit I3 and the water supply line. water supply adjustment that instructs the water supply amount of the water supply line 5 based on the signal from the flowmeter 7 provided in the water supply line 5, and adjusts the water supply rate by appropriately opening and closing the valve 9 provided in the water supply line 5; Total, sign! Reference numeral 5 denotes a remote manual setting device which controls the opening and closing of the blow valve 10 based on signals from a control room etc. that collectively monitors the converter boiler B.

Control of the water level within the drum 1 can be roughly divided into control when the converter is in operation and control when the converter is inactive. The control during operation of the converter is such that water is supplied into the drum l according to the steam flow rate obtained from the flow meter 7 installed in the steam line 4.
This is basically done by appropriately opening and closing a valve 9 provided in the water supply line 5. In this case, the water in the drum 1 expands as the water temperature increases, and the water level gradually rises from that level. Therefore, if the drum level indicator 12 reports an abnormality in the water level in the drum 1, the This drum level indicator is used by the inspector! Using the manual output from 2, a signal is input to the calculator 13, which opens and closes the valve provided in the water supply line 5 appropriately to adjust the water supply amount, and adjust the water level in the drum 1 to an appropriate value. There are 4. Also, although control is not normally performed at the time of the converter body 111, the water level in the drum 1 is 7. ! If it constantly decreases, 1i as in the case of converter operation
Utilizing the alarm signal from the indicator 12 indicated in ff, the relay 2o is switched, and the valve 9 of the water supply line 5 is appropriately opened and closed via the 1st flow generator 21 to adjust it to an appropriate value. In addition, if the water level rises due to the drain of high-pressure steam blown in during the above-mentioned shutdown, a supervisor who monitors the converter boiler B all at once from a distance can adjust the drainage line 6 via the remote manual setting device 15. The blow valve 10 is opened and closed appropriately to adjust it to an appropriate value.

"Problems to be Solved by the Invention" By the way, the method of controlling the water level in the converter boiler drum of the former Jyo-U.S. , manually close the valve 9 of the water supply line 5 and the blow valve I of the drain line 6.
Since the water level in the drum 1 was controlled by opening and closing O appropriately, the monitor had to constantly monitor the water level in the drum 1, and the control also depended on the monitor's experience and intuition. The drawback was that there were a lot of things to do.

The problem of this invention is how to realize a water level control method for a converter boiler drum that does not require constant human monitoring and can be controlled automatically.

"Means for Solving the Problems" The present invention provides a means for detecting the operating state of the converter to determine the operating state of a converter boiler drum provided in the converter at least between the stable operating period and the converter. What is the stable period when the furnace is out of service? Based on the signal from the detection means, the water level in the converter boiler drum during the converter shutdown stable period is determined from the water level rise during the converter operating stable period to the converter operating stable period. The above problem is solved by configuring a water level control method for a converter boiler drum that controls the water level to a level obtained by subtracting at least the expansion of water due to the temperature difference in the boiler between the converter shutdown and stable period. ing.

"Operation" In this invention, the operating state of the converter boiler is divided into at least the converter operating stable period and the converter idle stable period. In addition, it is possible to control the water level in the converter boiler drum during the stable period when the converter is out of operation to a level that is equal to the water expansion subtracted from the water level during the stable period when the converter is in operation. Therefore, even if the water level fluctuates due to fluctuations in the water temperature in the boiler, it is possible to stably control the water level in the drum during the stable operating period of the converter and the stable period of converter shutdown.

"Embodiments" Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a water level control method for a converter boiler drum, which is an embodiment of the present invention. The configuration of the converter boiler to which the water level control method of the present invention is applied is almost the same as the conventional converter boiler. Therefore, the same components are given the same reference numerals, and their explanations will be omitted.

The difference between the converter boiler B to which the water level control method of the present invention is applied and the conventional converter boiler is that the program controller 16 monitors and controls the water 11' level in the drum 141 of the boiler B. and this program J,']
Following the signal from Setsu 16, the drums multiplied! ,
1. A process management control system that monitors and displays the control status of... and controls them all at once! 7 is a point attached to converter boiler B. In FIG. 1, a program controller 16 is attached to the drum 1.
The program controller 16 is connected to the water level gauge 11 of the drum 1, the flow meter 7 of the steam line 4, and the water supply line 5.
Also, based on the signal input manually from the detection means 18 for detecting the operating state of the converter, the valve 9 of the water supply line 5 is outputted with an appropriate opening/closing shift signal of 4 degrees. The water level of the drum 1 is set at multiple points on the face of the program controller 16.
As a result, the program controller 16 detects the detection means 18.
The water level in the drum l is controlled and adjusted to this set water level over time based on the signal. Additionally, the converter boiler B is equipped with a process management control system 1.
7 is provided, and this process management control system 17 includes:
Based on the signals inputted from the water level gauges 11.11, . . . of the drums 111, .
Also, the blow valve 10, lOl of the drain line 6.6,...
... is output to the remote manual setting device 15. A communication cable 1 is connected between the 1-gram controller I6.16, ... and the process management control system 1.17.
9.19,... have been installed to enable mutual signal exchange. Here, a detection means for detecting the operating status of the converter! 8 is constituted by, for example, a means for detecting a limit signal of a gate valve provided in the converter.

Next, with reference to FIGS. 1 and 3 to 5, a method for controlling the water level of a converter boiler drano, which is an embodiment of the present invention, will be explained.

Based on the signal from the detection means 18, the operating state of the converter boiler drum I is determined between the converter operating start period from the start of the converter operation until the converter operation stabilizes, and the converter operating state when the converter is in a stable operating state. The converter is divided into a stable period, a stable period in which the converter is not in operation and a stable period in which the converter is in a stable condition in which the converter is not in operation. And converter boiler drum I
Control methods are set corresponding to each period, including water level control. The control method will be explained in detail for each of the three periods below.

(i) Converter operation start period As mentioned above, when the converter transitions from shutdown to operation,
The increase in water temperature in the drum 1 causes the water to expand and thus rise above the water level in the drum 1. However, at the same time, as mentioned above,
There is inevitably an upper limit to the water level in the drum 1 for stable operation of the converter boiler B. Therefore, for stable operation of the converter boiler 13, there is an operating water level SP in the drum AI, and an operating water level S1).

From, the drum l during the converter operation stable period and the converter idle stable period
The water level SP1 at rest is set in advance by the program controller 16 by subtracting at least 6 by the expansion amount due to the temperature difference of the water in the converter, and as shown in FIG. The program controller 16 controls the water level in the drum 1 to linearly rise from the resting water level SP to the operating water level S I) until the rising time 11 of . Here, the water level level Sp+ at rest, the water level SP t during operation, and the rising time t1 are determined experimentally in consideration of the influence of the time constant of the converter and converter boiler B, etc.

(ii) Stable period of converter operation The water level control in the drum l during the stable converter operation period is similar to the conventional control described above. Basically, this is done by appropriately opening and closing a valve 9 provided in the water supply line 5 so as to supply water to the drum I. However, in the above control method, the water level inside the drum 1 at that time is not considered, so the water level during operation S I)
It is necessary to add the deviation of the current water level in the drum 1 from , as a correction amount for the steam flow m.

Therefore, the control equation for determining the amount of water supplied from the water supply line 5 to the drum 1 can be expressed as the following equation.

1o=I M +Is K Here, Io is the water supply amount, IM is the drum level indicator 12
Is is the steam flow 1 based on the signal from the flow meter 7, and K is a bias canceller that cancels out the influence of equipment deviations such as the drum level indicator 12. According to this control formula, the program controller 16
outputs a control signal to the valve 9 of the water supply line 5 based on an input signal such as a drum level indication 31°12.

(iii) Immediately after the converter body is shut down When the operation of the converter is stopped, the water temperature in the converter boiler B gradually decreases, and therefore the water level in the drum I decreases as the water contracts. In other words, immediately after the converter is shut down, the opposite phenomenon occurs when the converter starts operating.

Therefore, as shown in FIG. 4, the water level control in the drum 1 immediately after the converter is stopped is to control the water level in the drum 1 from immediately after the converter is stopped (time t = 0) to a predetermined lowering time t. The program controller 16 may control the water level so that the water level falls linearly from the operating water level SP t to the operating water level SP. Here, the descent time in ml is determined experimentally in consideration of the influence of the time constant of the converter and converter boiler r3. Then, when the steam flow rate obtained from the flow meter 7 of the steam line 4 drops to, for example, 5% or less of the full scale of the flow meter 7, the program controller 16 takes into account the equipment error of the flow meter 7. Then, a signal for forcibly closing the valve 9 of the water supply line 5 is output. The point at which the valve 9 is forcibly closed may be determined as appropriate based on the minimum measurement range of the flowmeter 7 and the like.

(iv) Converter outage and stability period During the converter outage and stability period, as mentioned above, there are two problems in the drum 1: an abnormal drop in the water level and an upper water level pipe due to the drain of high-pressure steam blown into the drum 1. A phenomenon occurs. Therefore, the water level control in the drum l is also controlled by these two methods.
This must be done in line with the two phenomena. In response to an abnormal drop in water level, if the water level drops by a certain amount from the resting water level SP1, the program controller 16 outputs a signal that opens the valve 9 of the water supply line 5 by a certain amount. , and when the water level in the drum l recovers to the rest water level SP, control is performed to output a signal to close the valve 9. In response to a rise in the water level, control is performed to adjust the opening degree of the blow valve IO in the drainage line 6 in proportion to the rise in the water level in the drum 1, as shown in FIG. Here, the point at which the opening of the blow valve starts is at the resting water level SP1, as shown in FIG.
It is not limited to , and can be arbitrarily changed like the proportionality constant. The control of this blow valve 10 is not carried out by the 7g controller 16, but by the output from the process management control system I, which collectively monitors and controls the converter boiler B, and controls the remote manual setting device 15. It is done through

With the above configuration, water +1Z level control of the converter boiler drum is performed. Here, in the water level control of the converter boiler drum according to the present invention, the converter boiler B
The operating status of the converter is divided into the period when the converter starts operating, the period when the converter is stable, the period immediately after the converter is shut down, and the period when the converter is stopped and stable. It is possible to perform control according to the cause, and the water level during the stable period of converter shutdown is 6 times higher than the water level during the stable period of converter operation.
Since the water level is set and controlled to a level that is at least subtracted by the expansion of water, even if the water level fluctuates due to fluctuations in water temperature in the converter boiler B, the It is possible to stably control the water level in the drum l.

Therefore, there is no need for a human being to constantly monitor the water level in the drum, and its control can also be performed using the 1-gram controller 1.
6 and process management control system! It can be done automatically with the help of 7. In other words, it is possible to realize a water level control method for a converter boiler drum that does not require constant human monitoring and can be controlled automatically.

Here, in this embodiment, the converter boiler drum l
The operating status of the converter is divided into four periods: the start of converter operation, the stable converter operation period, the period immediately after the converter is stopped, and the stable period when the converter is stopped.
To control the water level of converter boiler drano, l,
Basically, it is sufficient to stably control the operating water level SP and the rest water level near the bell SP, and with that color, the operating state of the converter boiler drum l can be stabilized. It can be said that the minimum necessary control can be carried out by separating the converter into two periods: the period and the stable period when the converter is out of service. However, as mentioned above, the converter boiler drum is always in use during operating conditions other than the converter operation stable period and the converter shutdown stable period. By monitoring and controlling the water level inside the tank, it becomes possible to perform more fine-grained control over the details.

Note that the method for controlling the water level of a converter boiler drum according to the present invention is not limited to the above embodiment.

For example, the control of the sewage water level during the converter operation start period and the converter shutdown stable period is not limited to a linear rise or fall as shown in Figures 3 and 4; Control such as descending may also be used. Furthermore, the control device used to control the water level is not limited to the program controller and process management control system in the embodiments, but may be any control device that can perform the control method over time.

"Effects of the Invention" As described in detail above, according to the present invention, the operating state p of the converter boiler drum provided in the converter is detected by the detecting means for detecting the operating state of the converter. The water level in the converter boiler drum is divided into a stable period of converter operation and a stable period of converter outage, and the water level in the converter boiler drum during the stable period of converter outage is determined based on the signal from the detection means. A method for controlling the water level of a converter boiler drum such that the water level is controlled to a level obtained by subtracting at least the expansion of water due to the temperature difference in the boiler between the stable operating period of the converter and the stable period of converter shutdown from the water level of . As a result, fluctuations in the water level in the converter boiler drum due to fluctuations in water temperature in the drum can be controlled in accordance with the cause, and the water level during the stable period of converter shutdown is 1i. Set the water level to a level that is at least the expansion of the water subtracted from the water level during the stable operation period of the converter.
Therefore, even if the water level fluctuates due to fluctuations in the water temperature in the converter boiler, it is possible to stably control the water level in the drum during the stable operating period of the converter and the stable period of converter shutdown. be. Therefore, there is no need for a human to constantly monitor the water level in the drum (and the control can be done automatically).

Therefore, it is possible to realize a water level control method for a converter boiler drum that does not require constant human monitoring and can be controlled automatically.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram illustrating a water level control method of a converter boiler draught, which is an embodiment of the present invention; FIG. 2 is a schematic diagram illustrating a conventional water level control method of a converter boiler draught 11; The figure is a diagram showing an example of the relationship between the water level of the converter boiler drum and time in the same example, Figure 4 is a diagram similar to Figure 3, and Figure 5 is the water level of the converter boiler drum in the same example. FIG. 6 is a diagram showing an example of the relationship between the level and the opening degree of the blow valve, and is a conceptual diagram showing this embodiment and a conventional converter boiler. B...Converter boiler! ...Drum, 18...Detection means.

Claims (1)

[Claims] The operating state of the converter boiler drum provided in the converter is divided into at least a stable converter operating period and a stable converter outage period by a detection means for detecting the operating state of the converter, and the detecting means detects the operating state of the converter boiler drum provided in the converter. Based on the signal, the water level in the converter boiler drum during the stable period of converter outage is determined from the water level in the stable period of converter operation to the boiler during the stable period of converter operation and the stable period of converter outage. A method for controlling a water level in a converter boiler drum, characterized in that the water level is controlled to a level obtained by subtracting at least an amount of expansion of water due to a temperature difference within the drum.