JP3971646B2 - Replenishment steam control method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a supplementary steam control method for supplying supplementary steam to a main system (main steam system) to which intermittently generated steam is supplied.
[0002]
[Prior art]
Since the converter gas generated during hot metal blowing in the converter is high temperature, various methods for recovering this heat have been proposed. For example, an intermittent steam generator (for example, a heat recovery device) is provided at the upper part of the converter furnace mouth and the heat is recovered as steam in a steam accumulator. It is supplied to equipment using steam such as general factory equipment. However, since the converter is operated intermittently, the steam is intermittent steam (OG steam) that is generated intermittently and difficult to use continuously. Has been.
For example, as shown in FIG. 2, an intermittent steam system introduction facility 70 includes an intermittent steam generator (for example, an OG boiler) 71 whose steam generation amount varies, and a steam accumulator 72 that stores the intermittent steam of the intermittent steam generator 71. When the amount of intermittent steam that can be supplied from the steam accumulator 72 and the steam main pipe 74 of the main system provided with a plurality of steam using devices 73 to which steam from the steam is supplied is reduced. And a replenishing steam generator 75 (for example, a fuel-fired boiler). The supplemental steam produced by the supplemental steam generator 75 is supplied to a power generation means (steam turbine generator) 76. Further, valves 77 and 78 are provided on the downstream side of the intermittent steam generator 71 and the supplementary steam generator 75, respectively, to regulate the inflow of steam into the steam main pipe 74 and the outflow of steam from the steam main pipe 74. ing.
In this system introduction facility 70, the supplementary steam produced by the supplementary steam generator 75 is supplied to the steam main 74 intermittently (when intermittent steam is no longer supplied to the steam main 74) and continuously. Is supplied to the power generation means 76.
[0003]
[Problems to be solved by the invention]
However, the above-described supplemental steam control method has the following problems.
As described above, the amount of supplemental steam introduced by the power generation means is controlled so that the pressure of the supplemental steam is controlled to a predetermined value in both cases where supplemental steam is supplied to the steam main pipe and not. It has been broken. At this time, if the pressure of the supplementary steam is higher than a predetermined value set in advance, the amount of supplementary steam that the power generation means infuses increases to increase the amount of power generation, and if the pressure of the supplementary steam is lower than the set value, The amount of replenishing steam to be reduced decreases, and the amount of power generation decreases. In this way, the amount of power generated by the power generation means fluctuates. Therefore, if the amount of power generation is excessive, the power is excessively supplied, and it is not economical to use useless energy. A stable supply cannot be achieved.
The present invention has been made in view of such circumstances, and an object of the present invention is to provide a replenishment steam control method that controls stable fluctuations by controlling pressure fluctuations in the main system and suppresses significant fluctuations in the amount of power generation. .
[0004]
[Means for Solving the Problems]
The replenishment steam control method according to the present invention that meets the above-described object is to supply intermittent steam to a main steam system equipped with a plurality of steam using devices from an intermittent steam system in which steam generation is intermittent by piping of the intermittent steam system. When the pressure of the intermittent steam supplied from the intermittent steam system drops, the main steam system is connected to the supplementary steam system from the supplementary steam system provided with the supplementary steam generator and the power generation means for taking in the steam generated by the supplemental steam generator. A supplemental steam control method for supplying supplemental steam to
The pressure of the supplementary steam in the piping of the supplementary steam system is controlled to a predetermined value by adjusting the amount of steam introduced by the power generation means provided in the supplemental steam system, and the power generation amount fluctuation of the power generation means within a predetermined time is Control is performed by adjusting the amount of supplemental steam generated from the supplemental steam generator, and a check valve is provided between the main steam system and the supplemental steam system to prevent intermittent steam supplied from the intermittent steam system. When the pressure drops and the steam pressure in the main steam system falls below the pressure in the supplementary steam, the pressure difference between the steam in the main steam system and the supplementary steam causes the pressure from the supplementary steam system to the main steam system via the check valve. When supplementary steam is supplied and the pressure of the intermittent steam supplied from the intermittent steam system rises and the steam pressure of the main steam system becomes higher than the pressure of the supplemental steam, the check steam is turned off by the check valve. Of replenishment steam to the grid To stop the feeding. As described above, when the pressure of the supplementary steam in the supplementary steam system is higher than a predetermined value set in advance, the amount of supplementary steam extracted and supplied from the power generation means is decreased, and when the pressure of the supplemental steam is lower than the predetermined value. Increases the amount of supplemental steam supplied by bleed. As a result, the amount of supplemental steam extracted from the power generation means fluctuates. Therefore, when the power generation amount of the power generation means is small, the amount of supplemental steam produced by the supplemental steam system is increased from the current level, and the power generation amount of the power generation means is large. In this case, the replenishment steam amount is reduced from the current level.
[0005]
In this way, the supply of supplementary steam from the supplementary steam system to the main steam system is controlled by the check valve, so that supply and stoppage of supplementary steam from the supplementary steam system are automatically performed according to the steam pressure of the main steam system. Can be done.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is an explanatory diagram of a system introduction facility to which the supplementary steam control method according to one embodiment of the present invention is applied.
[0007]
As shown in FIG. 1, a system introduction facility 10 to which a supplementary steam control method according to an embodiment of the present invention is applied includes an OG boiler (an example of an intermittent steam generator) 11 in which the amount of steam generated varies. An intermittent steam system 12, a main steam system (also referred to as a main system) 15 including a steam main pipe 14 provided with a plurality of steam using devices 13 to which intermittent steam from the intermittent steam system 12 is supplied, and an intermittent steam system And a supplementary steam system 17 having a fuel-fired boiler (an example of a supplemental steam generator) 16 that supplies supplementary steam to the main steam system 15 when the pressure of the steam in the steam accumulator 22 supplied from 12 decreases. Equipment. Each device of the system introduction facility 10 is operated by a control device (not shown) such as a control computer. This will be described in detail below.
[0008]
In the intermittent steam system 12, the OG boiler 11 generates high-temperature and high-pressure steam by exchanging latent heat and sensible heat of the recovered converter gas, and the amount of intermittent steam produced is, for example, 0 to 0 per unit time. It fluctuates in the range of 400t, and the average is about 80-90t. One or two or more OG boilers 11 can be installed depending on the number of converters (not shown), and a pipe 18 is connected to the OG boiler 11. A branch point X is provided on the upstream side of the pipe 18, and a branch valve 19 branched from the branch point X is provided with a diffusion valve 20. Thereby, when the pressure of the intermittent steam of the intermittent steam system 12 provided with the OG boiler 11 becomes an excessive pressure, the intermittent steam can be exhausted by the diffusion valve 20 and the pressure of the intermittent steam can be adjusted. .
Further, a branch point Y is provided on the downstream side of the branch point X of the pipe 18, and a steam accumulator 22 (stores the steam produced by the OG boiler 11) at the downstream end of the branch pipe 21 branched from the branch point Y. For example, the capacity is about 300 m ³ ). Note that the pressure in the steam accumulator 22 (for example, about 3.7 MPa at the maximum) is measured by a pressure gauge (not shown), and this measured pressure is input to the control device. Further, a pressure reducing valve 23 is provided on the downstream side of the branch point Y of the pipe 18 to depressurize, for example, 3.7 MPa steam to, for example, about 2.0 MPa (1.9 MPa in this embodiment).
[0009]
In the supplementary steam system 17, the fuel-fired boiler 16 continuously generates high-temperature and high-pressure steam, and the amount of supplementary steam produced is, for example, about 60 to 120 t per unit time. Here, two fuel-fired boilers 16 are disposed, but one may be disposed, or three or more may be disposed. A pipe 24 is connected to the fuel-fired boiler 16, and a branch point Z is provided in the pipe 24. At the downstream end of the branch pipe 25 branched from the branch point Z, a steam turbine generator (an example of a power generation means) 26 for taking in steam generated in the fuel-fired boiler 16 is provided. About 120 tons are included, and power is generated about 3 to 24 MW, for example. The supplemental steam generated in the fuel-fired boiler 16 is supplied to the steam turbine generator 26, and the generated power can be used.
The supplementary steam in the pipe 24 is controlled to have a pressure (predetermined value) of, for example, about 1.5 MPa by operating the steam turbine generator 26.
[0010]
A control valve 27 for switching between flow rate control and pressure control is provided at the downstream end of the pipe 18 of the intermittent steam system 12, and the steam main pipe 14 of the main steam system 15 is continuously connected via the control valve 27. Connected. Thereby, the intermittent steam is supplied to the steam main pipe 14 via the control valve 27, and further supplied from the steam main pipe 14 to the plurality of steam using devices 13.
A check valve 28 is provided at the downstream end of the pipe 24 of the replenishment steam system 17, and the steam main pipe 14 of the main steam system 15 is continuously connected via the check valve 28. Thereby, when the pressure of the steam in the steam accumulator 22 supplied from the intermittent steam system 12 is reduced and the pressure of the steam in the main steam system 15 is lower than the pressure of the supplementary steam, the supplementary steam system 17 to the main steam system 15 It becomes possible to supply supplemental steam. On the other hand, when the steam in the steam accumulator 22 is supplied from the intermittent steam system 12 to the main steam system 15 and the steam pressure in the main steam system 15 is higher than the pressure of the supplemental steam, the steam from the main steam system 15 to the supplemental steam system 17 is supplied. Steam flow can be prevented. In this way, the flow of supplemental steam to the main steam system 15 can be controlled with a simple configuration, which is economical.
[0011]
The steam in the steam main pipe 14 of the main steam system 15 is set to a predetermined pressure, that is, 1.6 MPa (for example, about 200 to 300 ° C.), and in order to stably operate the system introduction facility 10, for example, 1.5 It is managed in a range of about ~ 1.6 MPa (management value). The pressure of each steam flowing through the intermittent steam system 12, the main steam system 15, and the auxiliary steam system 17 is sensed by sensors provided in the pipe 18, the steam main pipe 14, and the pipe 24, respectively, and is sent to the control device. And controlled.
Accordingly, the steam pressure (1.9 MPa) in the steam accumulator 22 supplied from the intermittent steam system 12 is reduced, and the steam pressure (1.6 MPa) in the main steam system 15 is replaced with the supplementary steam pressure (1.5 MPa). In the case of lowering, the supplemental steam is supplied from the supplemental steam system 17 to the main steam system 15 via the check valve 28 due to the differential pressure between the steam of the main steam system 15 and the supplemental steam. For this reason, since the pressure of the steam of the main steam system 15 can be stabilized within the range of the control value, the operation can be stably performed.
Further, when the pressure of the steam in the steam accumulator 22 supplied from the intermittent steam system 12 rises and the pressure of the steam in the main steam system 15 becomes higher than the pressure of the supplementary steam (1.5 MPa), the check valve 28. Thus, the supply of supplementary steam from the supplementary steam system 17 to the main steam system 15 is stopped, and the steam in the steam accumulator 22 is supplied from the intermittent steam system 12 to the main steam system 15. For this reason, intermittent steam can be supplied to the main steam system 15 to the maximum extent.
[0012]
Here, when the pressure of the steam of the main steam system 15 is less than a predetermined pressure (1.6 MPa), the control of the control valve 27 is switched to flow control, a speed gradient is provided in the supply amount of intermittent steam, and the steam accumulator 22 accumulates. The flow rate is continuously controlled so that the intermittent steam can be supplied to the maximum.
On the other hand, when the steam pressure in the main steam system 15 is equal to or higher than a predetermined pressure (1.6 MPa), the control of the control valve 27 is switched to pressure control, the amount of intermittent steam introduced into the steam main pipe 14 is limited, and the main steam The pressure of the intermittent steam flowing to the system 15 is controlled to 1.6 MPa.
Note that the control of the control valve 27 is switched automatically by checking the steam pressure in the main steam system 15 in real time and by a control device (not shown). Thereby, workability | operativity is made favorable and it becomes possible to operate the system | strain introduction equipment 10 stably.
[0013]
Next, a supplementary steam control method according to an embodiment of the present invention will be described with reference to the system introduction facility 10 described above.
Usually, intermittent steam is stored in the steam accumulator 22, the pressure of the steam supplied to the main steam system 15 is within the range of the control value, and the pressure of the steam exceeds the pressure of the supplementary steam (predetermined value). In this case, the control valve 27 is opened by the control device based on the measured pressure, and the steam in the steam accumulator 22 is supplied from the intermittent steam system 12 to the main steam system 15 provided with the plurality of steam using devices 13. Here, when the pressure of the steam in the steam main pipe 14 of the main steam system 15 is less than a predetermined pressure, the control valve 27 is controlled by the control device as a flow control, and intermittent steam is supplied to the main steam system 15 to the maximum. The pressure of the steam in the steam main pipe 14 is maintained within the control value range. On the other hand, when the pressure of the steam in the steam main pipe 14 is equal to or higher than a predetermined pressure, the control device 27 controls the control valve 27 to control the pressure so that the steam pressure in the steam main pipe 14 can be maintained at the predetermined pressure. . At this time, since the pressure of the steam in the steam main pipe 14 is higher than the pressure of the supplementary steam, the check valve 28 prevents the steam from flowing from the main steam system 15 to the supplementary steam system 17.
[0014]
On the other hand, the amount of intermittent steam in the steam accumulator 22 also decreases, the steam pressure in the steam accumulator 22 supplied to the main steam system 15 decreases, and the steam pressure in the steam main pipe 14 falls below the lower limit value of the control value. In this case, that is, when the pressure of the intermittent steam is lower than the pressure of the supplementary steam (predetermined value), the flow rate gradient K set in advance below the follow-up ability of the supplementary steam based on the measured pressure (for example, about 4.5 t / h / min) Then, the control valve 27 is closed by the control device, the supplementary steam is supplied from the supplementary steam system 17 to the main steam system 15 by the check valve 28, and the steam pressure in the steam main pipe 14 is maintained within the control value range. .
[0015]
Here, the pressure control of the supplemental steam in the supplemental steam system 17 will be described.
The pressure of the supplementary steam in the supplementary steam system 17 is predetermined by operating the steam turbine generator 26 (fluctuating the amount of extraction) by the controller based on the measured pressure of supplementary steam in the pipe 24 sent to the controller. Controlled by value. Since the steam turbine generator 26 has good response (can be operated in a short time), the amount of supplemental steam extracted in a short time can be adjusted by the control device. As a result, the pressure of the supplemental steam can be easily controlled to a predetermined value, so that fluctuations in the pressure of the steam in the main steam system 15 can be suppressed even when supplemental steam is supplied to the steam main pipe 14.
[0016]
Thus, since the amount of supplementary steam extracted from the steam turbine generator 26 fluctuates, the resulting power generation amount also fluctuates. Therefore, when the amount of power generated by the steam turbine generator 26 sent to the control device is small, the fuel-fired boiler 16 is cooked up by the control device, and the amount of supplemental steam to be manufactured is increased from the current level. When the amount of power generated by the steam turbine generator 26 sent to the control device is large, the control device reduces the fuel in the fuel-fired boiler 16 from the current state, and reduces the amount of supplementary steam to be manufactured from the current state. The amount of supplemental steam generated by the fuel-fired boiler 16 is adjusted within a predetermined time, for example, within one hour. This is because attention is paid to the fact that the power supply and demand management is indicated by the power consumption per unit time (KWH), whereby the power generation fluctuation of the steam turbine generator 26 can be easily controlled. In this way, since the fluctuation of the power generation amount of the steam turbine generator 26 may be controlled within one hour, the adjustment of the amount of supplemental steam generated is not responsive (it takes time to operate) the fuel-fired boiler 16. Even when used, it can be easily performed.
[0017]
Then, the blowing of the converter is started again, intermittent steam is stored in the steam accumulator 22, and when the steam pressure in the steam accumulator 22 exceeds the pressure of the supplementary steam, the controller controls the measured pressure. The control valve 27 is opened at the flow rate gradient K, and steam is supplied from the intermittent steam system 12 to the main steam system 15 provided with the plurality of steam using devices 13.
Thereby, the pressure of the steam in the steam main pipe 14 of the main steam system 15 can be controlled within the range of the management value without being affected by the presence or absence of steam supply from the intermittent steam system 12.
[0018]
As described above, the present invention has been described with reference to one embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and is described in the claims. Other embodiments and modifications conceivable within the scope of the above are also included.
For example, the present invention is also applied to the case where the supplementary steam control method of the present invention is configured by combining some or all of the above-described embodiments and modifications.
Moreover, in the said embodiment, the case where a fuel-fired boiler was used as a supplemental steam generator was demonstrated. However, it is also possible to provide other supplemental steam generators such as a CDQ that utilizes heat generated during the cooling of coke.
[0019]
【The invention's effect】
The replenishing steam control method according to claim 1, wherein when the replenishing steam pressure of the replenishing steam system is higher than a predetermined value set in advance, the amount of replenishing steam extracted and supplied from the power generation means is reduced, and replenishing is performed. When the steam pressure is lower than a predetermined value, the amount of supplementary steam supplied by extracting is increased. As a result, supplementary steam adjusted to a predetermined pressure can be immediately supplied to the main steam system, so even if steam cannot be supplied to the main steam system from the intermittent steam system, fluctuations in the steam pressure in the main steam system are suppressed. The equipment can be operated stably. Further, since the amount of supplementary steam extracted from the power generation means varies, when the power generation amount of the power generation means is small, the power generation means within a predetermined time is increased by increasing the amount of supplementary steam produced by the supplementary steam generator from the current level. Can be controlled within a target range. Therefore, it is economical without excessive power generation, and sufficient power generation can be performed for use by the apparatus, so that power can be stably supplied.
[0020]
In addition , since the supply of supplementary steam from the supplementary steam system to the main steam system is controlled by the check valve, the supplementary steam is automatically supplied and stopped from the supplementary steam system according to the steam pressure of the main steam system. be able to. In this way, it is possible to control the steam pressure of the main steam system to a level at which stable operation is possible simply by controlling the pressure of the supplementary steam in the supplementary steam system to a predetermined value, so that the equipment can be operated stably and the workability is good. It becomes.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a system introduction facility to which a supplementary steam control method according to an embodiment of the present invention is applied.
FIG. 2 is an explanatory diagram of a system introduction facility according to a conventional example.
[Explanation of symbols]
10: System introduction equipment, 11: OG boiler (intermittent steam generator), 12: intermittent steam system, 13: steam using device, 14: steam main, 15: main steam system, 16: fuel-fired boiler (supplemental steam generation) Equipment), 17: supplementary steam system, 18: piping, 19: branch pipe, 20: diffusion valve, 21: branch pipe, 22: steam accumulator, 23: pressure reducing valve, 24: piping, 25: branch pipe, 26: steam turbine generator (Power generation means), 27: control valve, 28: check valve

Claims (1)

Intermittent steam is supplied from an intermittent steam system in which steam generation is intermittent to a main steam system having a plurality of steam using devices through piping of the intermittent steam system, and the pressure of the intermittent steam supplied from the intermittent steam system is In the case of a drop, the replenishment steam that supplies replenishment steam to the main steam system through the replenishment steam system piping from the replenishment steam system provided with the replenishment steam generation device and the power generation means for taking in the steam generated by the replenishment steam generation device A control method,
The pressure of the supplementary steam in the piping of the supplementary steam system is controlled to a predetermined value by adjusting the amount of steam introduced by the power generation means provided in the supplemental steam system, and the power generation of the power generation means within a predetermined time The amount fluctuation is controlled by adjusting the generation amount of the supplemental steam from the supplemental steam generator, and a check valve is provided between the main steam system and the supplemental steam system, and the intermittent When the pressure of the intermittent steam supplied from the steam system is reduced, and the pressure of the steam of the main steam system is lower than the pressure of the supplemental steam, due to the differential pressure between the steam of the main steam system and the supplementary steam, The supplementary steam is supplied from the supplementary steam system to the main steam system via the check valve, and the pressure of the intermittent steam supplied from the intermittent steam system is increased, and the steam pressure of the main steam system is increased. Before When it becomes higher than the pressure of the refill steam, the control method of replenishing the vapor, characterized by stopping the supply of said replenishing steam to the main steam line from the refill steam system by the check valve.

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