JP4091795B2 - System for introducing intermittently generated steam and method for introducing the system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a system introduction facility for intermittently generated steam for supplying intermittent steam, which is intermittent in steam generation, to a main steam system (main system) and a system introduction method therefor.
[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, a heat recovery device is provided in a hood or the like that covers the upper part of the converter furnace mouth, and heat is recovered as steam (an example of intermittent steam). It is supplied to equipment using steam such as general factory equipment. However, since the converter is intermittently operated, steam is generated intermittently and it is difficult to use it continuously. Therefore, a method of effectively using this steam has been proposed.
For example, JP-A-60-95106 discloses a steam supply control method for supplying OG steam obtained from a heat recovery device and steam obtained from a fuel-fired boiler to a combined air supply pipe (main system). It is disclosed. This predicts the evaporation amount of the heat recovery device and the pressure fluctuation in the steam accumulator based on the converter blowing information, and in order to eliminate this predicted pressure fluctuation, the OG steam from the steam accumulator to the combined gas supply pipe A method that prioritizes air supply, controls the amount of OG steam and steam obtained from a fuel-fired boiler to the combined air supply pipe, and opens and closes the valve based on a sequence so that the pressure of the combined air supply pipe does not become excessive pressure is there.
[0003]
[Problems to be solved by the invention]
However, the above-described intermittent steam generation system introduction method has the following problems.
Since the prediction may be lost due to fluctuations in converter blowing information, etc., pressure fluctuations may occur in the main system. Here, when the pressure of the main system becomes excessively high, it becomes impossible to control the pressure of the main system. On the other hand, when the pressure of the main system decreases, it becomes impossible to supply steam to the steam using device and perform stable operation. I can't. At this time, it is good that the steam turbine can freely absorb the pressure fluctuation, but there is a problem that the steam fluctuation using the fuel-fired boiler cannot absorb the pressure fluctuation.
Even in a state where a large amount of OG steam can be supplied, steam from the fuel-fired boiler is supplied to the main system, which is uneconomical.
The present invention has been made in view of such circumstances, and provides a system introduction facility for intermittently generated steam that can be operated economically while controlling the pressure fluctuation of the main steam system and a system introduction method thereof. With the goal.
[0004]
[Means for Solving the Problems]
A system introduction facility for intermittently generated steam according to the present invention in accordance with the above object includes an intermittent steam system provided with an intermittent steam generator whose steam generation amount fluctuates, and a plurality of steam using devices that use intermittent steam from the intermittent steam system And a replenishment steam generator for supplying replenishment steam to the main steam system via a check valve when the pressure of the intermittent steam supplied from the intermittent steam system falls below a preset pressure. possess a refill steam system having, moreover, the piping of the intermittent steam system, the control valve is provided for switching between the flow rate control and pressure control, is connected to the pipe of the main steam system through the control valve If the steam pressure of the main steam system is less than the preset pressure, the control valve controls the flow rate of intermittent steam flowing to the main steam system, and the steam pressure of the main steam system is greater than or equal to the predetermined pressure. To the main steam system Controlling the pressure of the intermittent steam. Thus, since the check valve is provided between the main steam system and the supplementary steam system, the supplementary steam can be automatically supplied and stopped from the supplemental steam system according to the steam pressure of the main steam system. it can.
[0005]
In the intermittent steam generation system introduction method according to the present invention, the intermittent steam is supplied from the intermittent steam system in which the steam generation amount varies to the main steam system provided with a plurality of steam use devices, and is supplied from the intermittent steam system. When the steam pressure drops below a preset pressure, this is a method for introducing intermittently generated steam that supplies supplementary steam from the supplementary steam system to the main steam system, and there is a reverse between the main steam system and the supplementary steam system. When the pressure of the intermittent steam supplied from the intermittent steam system is reduced and the pressure of the steam of the main steam system is lower than the pressure of the supplemental steam, the differential pressure between the steam of the main steam system and the supplemental steam Thus, 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 rises, and the steam pressure of the main steam system becomes the pressure of the supplementary steam. When it gets higher Check valve by stopping the supply of replenishing steam from refill steam system into the main steam system, moreover, between the main steam line and the intermittent steam system, a control valve for switching between flow control and pressure control are provided When the steam pressure of the main steam system is lower than the preset predetermined pressure by the control valve, the flow rate of the intermittent steam flowing to the main steam system is controlled, and when the steam pressure of the main steam system is higher than the predetermined pressure Control the pressure of intermittent steam flowing to the main steam system . 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.
Also , since the intermittent steam supply method from the intermittent steam system to the main steam system is changed by the control valve, the intermittent steam supplied from the intermittent steam system to the main steam system is used when the steam pressure of the main steam system is lower than the predetermined pressure. Can be supplied at a maximum by flow control, and can be supplied by controlling the pressure only at the time of overpressure.
[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.
FIG. 1 is an explanatory diagram of the system introduction facility for intermittently generated steam according to one embodiment of the present invention.
[0007]
As shown in FIG. 1, an intermittently generated steam system introduction facility (hereinafter also simply referred to as a system introduction facility) 10 according to an embodiment of the present invention is an OG boiler (of an intermittent steam generator) whose steam generation amount varies. Example) From an intermittent steam system 12 provided with 11, a main steam system (also referred to as main system) 14 provided with a plurality of steam using devices 13 that use intermittent steam from the intermittent steam system 12, and an intermittent steam system 12 Replenishment provided with a fuel-fired boiler (an example of a supplemental steam generator) 16 that supplies supplemental steam to the main steam system 14 via a check valve 15 when the pressure of the intermittent steam supplied falls below a preset pressure. This is a facility having a steam system 17. 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 generated intermittent steam amount is, for example, 0 to 400 t per unit time. The average is about 80 to 90 t. 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 downstream of the branch point X of the pipe 18, and a steam accumulator 22 (stores steam generated in 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 ). 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 about 2.0 MPa (1.9 MPa in this embodiment).
[0009]
In the supplementary steam system 17, the fuel-fired boiler 16 continuously produces high-temperature and high-pressure steam, and the amount of supplementary steam produced is, for example, about 60 to 120 t / hour. 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. A steam turbine generator 26 is provided at a downstream end portion of the branch pipe 25 branched from the branch point Z, and steam is charged, for example, at about 15 to 120 t / hour, and electric power is generated, for example, at about 3 to 24 MW. Normally, supplemental steam generated in the fuel-fired boiler 16 is supplied to the steam turbine generator 26 and used to generate electric power.
The supplemental steam in the pipe 24 has a pressure of about 1.5 MPa, for example, and a temperature of about 300 ° C., for example.
[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 is connected to the pipe 28 of the main steam system 14 via the control valve 27. Yes. Thereby, when the main steam system 14 uses intermittent steam, the intermittent steam is supplied to the pipe 28 via the control valve 27, and further supplied from the pipe 28 to the plurality of steam using devices 13.
A check valve 15 is provided at the downstream end of the pipe 24 of the supplementary steam system 17, and is connected to the pipe 28 of the main steam system 14 via the check valve 15. Thereby, when the pressure of the intermittent steam supplied from the intermittent steam system 12 decreases and the pressure of the steam of the main steam system 14 decreases below the pressure of the supplemental steam, the supplemental steam from the supplemental steam system 17 to the main steam system 14 Can be supplied. On the other hand, when intermittent steam is supplied from the intermittent steam system 12 to the main steam system 14 and the steam pressure in the main steam system 14 is higher than the pressure of the supplementary steam, the steam flows from the main steam system 14 to the supplementary steam system 17. Can be prevented. In this way, the flow of supplemental steam to the main steam system 14 can be controlled with a simple configuration, which is economical.
[0011]
The steam in the pipe 28 of the main steam system 14 is set to a predetermined pressure, that is, 1.6 MPa (for example, 200 to 300 ° C.), and in order to operate the system introduction equipment 10 stably, for example, 1.5 to 1 It is managed in the range of about 6 MPa (control value).
The pressure of each steam flowing through the intermittent steam system 12, the main steam system 14, and the auxiliary steam system 17 is sensed by sensors provided in the pipe 18, the pipe 28, and the pipe 24, respectively, and sent to the control device. It is controlled.
Therefore, when the pressure (1.9 MPa) of the intermittent steam supplied from the intermittent steam system 12 is reduced and the pressure (1.6 MPa) of the steam of the main steam system 14 is lower than the pressure of the supplementary steam (1.5 MPa). The supplementary steam is supplied from the supplementary steam system 17 to the main steam system 14 via the check valve 15 due to the differential pressure between the steam of the main steam system 14 and the supplementary steam. For this reason, since the pressure of the steam of the main steam system 14 can be stabilized within the range of the control value, the operation can be stably performed.
[0012]
Further, when the pressure of the intermittent steam supplied from the intermittent steam system 12 increases and the pressure of the steam in the main steam system 14 becomes higher than the pressure of the supplementary steam (1.5 MPa), the check valve 15 causes the supplemental steam system. The supply of supplemental steam from the main steam system 14 to the main steam system 14 is stopped, and the flow of steam from the main steam system 14 to the supplemental steam system 17 is prevented, so that intermittent steam is generated from the intermittent steam system 12 to the main steam system 14. Supplied. For this reason, the intermittent steam can be supplied to the main steam system 14 to the maximum extent.
[0013]
Here, when the steam pressure of the main steam system 14 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 to the supply amount of intermittent steam, and the steam accumulator 22 is accumulated. 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 14 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 pipe 28 is limited, and the main steam system 14 The pressure of the intermittent steam flowing to is controlled to 1.6 MPa.
The control of the control valve 27 is switched automatically by confirming the steam pressure of the main steam system 14 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.
[0014]
Next, an intermittently generated steam system introduction method according to an embodiment of the present invention will be described with reference to the intermittently generated steam system introduction facility 10.
Usually, when intermittent steam is stored in the steam accumulator 22, the pressure of the intermittent steam supplied to the main steam system 14 is within the range of the control value, and the pressure of the intermittent steam exceeds the pressure of the supplemental steam, Intermittent steam is supplied from the intermittent steam system 12 to the main steam system 14 provided with a plurality of steam using devices 13. Here, when the pressure of the steam in the pipe 28 of the main steam system 14 is less than a predetermined pressure set in advance, the control valve 27 is controlled by the control device to control the flow rate, and intermittent steam is supplied to the main steam system 14 as much as possible. The vapor pressure in the pipe 28 is maintained within the control value range. On the other hand, when the pressure of the steam in the pipe 28 is equal to or higher than the predetermined pressure, the control valve 27 is controlled by the control device so that the pressure of the steam in the pipe 28 can be maintained at the predetermined pressure. At this time, since the pressure of the steam in the pipe 28 is higher than the pressure of the supplemental steam, the check valve 15 prevents the steam from flowing from the main steam system 14 to the supplemental steam system 17.
[0015]
On the other hand, the amount of intermittent steam in the steam accumulator 22 is reduced, the pressure of the intermittent steam supplied to the main steam system 14 decreases, and the steam pressure in the pipe 28 falls below the lower limit value of the control value, that is, intermittent steam. Is lower than the pressure of the supplemental steam, the supplementary steam is supplied from the supplemental steam system 17 to the main steam system 14 by the check valve 15, and the steam pressure in the pipe 28 is maintained within the control value range.
Here, when the blowing of the converter is started again, intermittent steam is stored in the steam accumulator 22, and the pressure of the intermittent steam exceeds the pressure of the supplementary steam, a plurality of steam using devices 13 are provided. Intermittent steam is supplied from the intermittent steam system 12 to the steam system 14.
Thereby, the pressure of the steam in the pipe 28 of the main steam system 14 can be controlled within the range of the management value without being affected by the presence or absence of the supply of intermittent steam.
[0016]
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 a case where the intermittently generated steam system introduction facility and the system introduction method of the present invention are 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 replenishing steam generators, for example, a coke dry fire extinguishing device (CDQ: Coke Dry Quencher) that uses heat generated when the coke is cooled.
[0017]
【The invention's effect】
In the system introduction facility for intermittently generated steam according to claim 1, since a check valve is provided between the main steam system and the supplemental steam system, supplementary steam from the supplemental steam system is selected according to the steam pressure of the main steam system. Can be automatically supplied and stopped. Therefore, the steam pressure in the main steam system can be controlled to a level at which stable operation is possible without being affected by the amount of intermittent steam supplied from the intermittent steam system to the main steam system. It becomes good. Further, when intermittent steam can be supplied in large quantities from the intermittent steam system to the main steam system, only intermittent steam can be supplied to the main steam system, and therefore, for example, the intermittent steam can be used without being diffused to the atmosphere, and is economical.
[0018]
In the method for introducing the intermittently generated steam system according to claim 2, since the supply of supplemental steam from the supplementary steam system to the main steam system is controlled by a check valve, the supplementary steam system according to the steam pressure of the main steam system The supply and stop of the supplemental steam from can be automatically performed. Therefore, the steam pressure in the main steam system can be controlled to a level at which stable operation is possible without being affected by the amount of intermittent steam supplied from the intermittent steam system to the main steam system. It becomes good. Further, when intermittent steam can be supplied in large quantities from the intermittent steam system to the main steam system, only intermittent steam can be supplied to the main steam system, and therefore, for example, the intermittent steam can be used without being diffused to the atmosphere, and is economical.
In addition , since a control valve for switching between flow control and pressure control is provided between the main steam system and the intermittent steam system, the intermittent steam supplied from the intermittent steam system to the main steam system is supplied to the steam of the main steam system. When the pressure is less than the predetermined pressure, the maximum supply is performed by the flow rate control, and the pressure can be controlled and supplied only at the time of excessive pressure increase. Accordingly, when a large amount of intermittent steam can be supplied, intermittent steam can be supplied to the main steam system without supplying supplementary steam from the supplementary steam system to the main steam system. It is economical. Further, when the pressure of the steam in the main steam system is excessively increased, the pressure of the intermittent steam supplied to the main steam system is controlled and supplied, so that the equipment can be operated more stably and the workability is improved.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of intermittent steam generation system introduction equipment according to an embodiment of the present invention.
[Explanation of symbols]
10: System introduction equipment for intermittently generated steam, 11: OG boiler (intermittent steam generator), 12: intermittent steam system, 13: steam using device, 14: main steam system, 15: check valve, 16: fuel-fired boiler (Supplementary steam generator), 17: Supplementary steam system, 18: Piping, 19: Branch pipe, 20: Dissipation valve, 21: Branch pipe, 22: Steam accumulator, 23: Pressure reducing valve, 24: Piping, 25: Branch pipe, 26: Steam turbine generator, 27: control valve, 28: piping

Claims (2)

An intermittent steam system provided with an intermittent steam generator with variable steam generation amount, a main steam system provided with a plurality of steam using devices that use intermittent steam from the intermittent steam system, and the intermittent steam system wherein when the pressure of the intermittent steam becomes lower than a preset pressure, possess a refill steam system with supplemental steam generator for supplying replenishment vapor through a check valve into the main steam system that,
In addition, the intermittent steam system pipe is provided with a control valve for switching between flow rate control and pressure control, and the main steam system pipe is connected via the control valve. When the steam pressure of the main steam system is less than a preset predetermined pressure, the flow rate of the intermittent steam flowing to the main steam system is controlled, and when the steam pressure of the main steam system is equal to or higher than the predetermined pressure, A system introduction facility for intermittently generated steam, wherein the pressure of the intermittent steam flowing to the main steam system is controlled . Supplying intermittent steam from an intermittent steam system with variable steam generation to a main steam system provided with a plurality of steam using devices, the pressure of the intermittent steam supplied from the intermittent steam system is lower than a preset pressure A system introduction method of intermittently generated steam for supplying supplementary steam from a supplementary steam system to the main steam system,
A check valve is provided between the main steam system and the supplemental steam system, the pressure of the intermittent steam supplied from the intermittent steam system is reduced, and the pressure of the steam of the main steam system is The supplementary steam is supplied from the supplementary steam system to the main steam system via the check valve due to the pressure difference between the steam of the main steam system and the supplementary steam, and the intermittent When the pressure of the intermittent steam supplied from the steam system rises and the pressure of the steam of the main steam system becomes higher than the pressure of the supplemental steam, the check valve causes the supplementary steam system to move to the main steam system. The supply of the supplemental steam is stopped ,
Moreover, a control valve for switching between flow rate control and pressure control is provided between the main steam system and the intermittent steam system, and the steam pressure of the main steam system is preset by the control valve. When the pressure is less than a predetermined pressure, the flow rate of the intermittent steam flowing to the main steam system is controlled, and when the steam pressure of the main steam system is equal to or higher than the predetermined pressure, the pressure of the intermittent steam flowing to the main steam system is controlled. A system introduction method for intermittently generated steam characterized by controlling .

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