JP7025957B2 - Steam temperature reduction system and steam temperature reduction method - Google Patents

Description

The steam temperature reducing system and the steam temperature reducing method according to the present application relate to a technique for reducing temperature and depressurizing when steam is used as a heat source.

The superheated steam generated by the boiler may be transferred to the supply destination in an industrial plant and used as a heat source in various processes. However, using this superheated steam as it is as a heat source has problems such as unstable temperature and low thermal conductivity. Therefore, it is necessary to reduce the temperature and depressurize the superheated steam to return it to saturated steam so that it is suitable as a heat source.

For this reason, the steam piping system is provided with a steam temperature reduction system (also referred to as a decompression temperature reduction system). This system has a warmer on the piping system. Water for lowering the temperature is supplied to the heater, and water is sprayed into the transferred superheated steam to mix it, and the steam is cooled and depressurized to return to saturated steam.

However, the amount of water injected to the thermostat requires precise control, and the water injection amount control system tends to be complicated. In this regard, there is a technique disclosed in Patent Document 1 described later. In this technology, a plurality of temperature reducers are installed in the piping system to gradually reduce the temperature and depressurize the superheated steam. Then, a plurality of thermometers are provided corresponding to each stage, each temperature is measured, and the whole is monitored to control the supply amount of cooling water.

Japanese Unexamined Patent Publication No. 2017-72313

However, the technique disclosed in Patent Document 1 described above has a problem that the configuration and control contents of the temperature reducing system become complicated.

Therefore, the steam temperature reduction system and the steam temperature reduction method according to the present application have a problem of solving these problems, and a steam temperature reduction system capable of reliably decompressing and depressurizing overheated steam with a simple configuration. And to provide a method for reducing the temperature of steam.

The steam temperature reduction system according to the present application is
A temperature-reducing means that produces a de-heated steam by supplying a de-heating liquid to the superheated steam and mixing it.
Separation means, which extracts and separates a liquid from the temperature-reducing vapor generated by the temperature-reducing means.
Vibration detection means, which detects vibration caused by evaporation of the liquid extracted by the separation means and outputs a vibration signal.
A control means that controls the supply amount of the cooling liquid based on the vibration signal,
It is characterized by being equipped with.

In the steam temperature reducing system and the steam temperature reducing method according to the present application, the vibration generated by the extracted liquid is detected and a vibration signal is output. Then, the supply amount of the temperature reducing liquid is controlled based on the vibration signal.

Here, when the supply amount of the temperature-reducing liquid mixed with the superheated steam is appropriate, the liquid separated from the heat-reducing steam or the temperature-reducing steam causes a peculiar vibration. Therefore, by controlling the supply amount of the heat-reducing liquid based on the vibration signal, it is possible to reliably reduce the temperature and depressurize the superheated steam with a simple configuration.

It is a block diagram of the temperature reduction system which shows one Embodiment of the steam temperature reduction system and the steam temperature reduction method which concerns on this application. It is a flowchart of the program about the temperature reduction of steam executed by the control unit shown in FIG.

[Explanation of terms in the embodiment]
The main terms shown in the embodiments correspond to the following elements of the steam decompression system and the steam decompression method according to the present application, respectively.
Heat reducer 2 ・ ・ ・ Temperature lowering means Separator 6 ・ ・ ・ Separation means Control unit 12 ・ ・ ・ Control means Monitoring sensor 25 ・ ・ ・ Vibration detection means, Temperature detection means, Re-evaporated steam detection means Water for lowering temperature ・ ・ ・Cooling liquid Water injection amount ・ ・ ・ Supply amount of warming liquid Saturated steam ・ ・ ・ Low temperature steam detection flash signal ・ ・ ・ Vibration signal, re-evaporation steam signal Detection temperature signal ・ ・ ・ Temperature signal

[First Embodiment]
The first embodiment of the steam temperature reducing system and the steam temperature reducing method according to the present application will be described. FIG. 1 is a block diagram of a temperature reducing system according to the present embodiment, and FIG. 2 is a flowchart of a program for cooling steam.

(Explanation of the overall configuration)
In an industrial plant or the like, the superheated steam generated by the boiler is transferred through a pipe, and the temperature is reduced or reduced under a temperature reducing system so as to be suitable for a heat source. In the temperature reducing system of the present embodiment, the temperature reducing device 2 is provided as shown in FIG. 1, and the superheated steam is first taken into the temperature reducing device 2.

Cooling water is supplied and injected into the warming device 2, and the warming water is sprayed toward the superheated steam in the warmer 2 and mixed with the superheated steam. As a result, the superheated steam is deheated and depressurized. The amount of water injected into the cooler 2 increases or decreases depending on the degree of opening and closing of the water injection valve 4, which is a control valve.

Since the steam emitted from the heater 2 contains water consisting of sprayed heat-reducing water and condensed drain of superheated steam, it is given to the separator 6 where the steam is liquid (heat-reduced). (Water and condensed drain) are extracted and separated and taken out. As the mechanism of the separator for separating the liquid and the gas, there are various methods such as a method using a baffle plate and a method of hitting the gas and the liquid against the mesh to drip the liquid part, but in this embodiment, there are various methods. Adopts a cyclone method that uses centrifugal force that utilizes the difference in specific weight between gas and liquid, and separates vapor and water more reliably.

That is, the inside of the main body of the separator 6 has a cylindrical shape, and when the steam passes through the built-in blade mechanism, the steam spirally swirls inside the main body. At this time, centrifugal force acts on the heat-reducing water mixed in the steam to blow it outward, and the steam and the water are separated.

The blown water adheres to the inner wall surface inside the main body, moves downward along the inner wall surface according to gravity, and is drained as a drain from the drain port. On the other hand, the steam from which the water has been removed is taken out from the exhaust stack provided on the central shaft in the main body. After the temperature is reduced and the pressure is reduced in this way, the steam in a state where the water is separated is used as a saturated steam as a heat source in various steps.

Here, since the drain, which is the water discharged from the separator 6, is in a high temperature and high pressure state, when it is exposed to a low pressure atmosphere due to the discharge, a part of it evaporates and is converted into flash steam (re-evaporated steam). do. However, it has been confirmed that the phenomenon of drain conversion to flash steam occurs only when the amount of warming water injected into the superheated steam is appropriate. That is, in the case of excessive water injection in which the amount of water injection is larger than the appropriate amount, the phenomenon of conversion to flash steam does not occur even if the drain is exposed to a low pressure atmosphere. In the case of insufficient water injection in which the amount of water injection is less than the appropriate amount, drainage does not occur and flash steam is unlikely to be generated.

In addition, when the amount of cooling water injected into the superheated steam is appropriate, the temperature of the drained drain shows a constant reference temperature a, but when excessive water is injected, the drain temperature becomes lower than the reference temperature a. In the case of insufficient water injection, the drain temperature becomes higher than the reference temperature a.

In the present embodiment, paying attention to these points, it is intended to control the injection amount of the cooling water to the superheated steam based on the presence / absence of flash steam generation and the temperature of the discharged drain.

The flash vapor is generated in the drainage pipe of the drain from the separator 6, which produces ultrasonic waves. In the present embodiment, the generation of flash vapor is detected by detecting the vibration peculiar to the ultrasonic wave.

In this embodiment, a steam trap 26 is provided on the drain pipe from the separator 6 in order to detect the presence or absence of ultrasonic vibration due to the generation of flash steam and the temperature of the drain discharged. A monitoring sensor 25 is provided between the trap 26 and the separator 6.

The detection head of the monitoring sensor 25 is provided with a piezoelectric element connected to a detection needle for detecting vibration and a thermocouple for detecting temperature (not shown), and vibration peculiar to flash steam and vibration and Detects the drain temperature. Then, the monitoring sensor 25 wirelessly transmits the detected vibration and temperature as a detected vibration signal and a detected temperature signal, respectively.

These signals transmitted by the monitoring sensor 25 are taken into the control unit 12 through the reception unit 16 in the control device 10. The control device 10 is provided with a memory 14. The control unit 12 gives an open signal or a close signal to the water injection valve 4 through the line 30 based on the captured signal.

(Explanation of temperature reduction program)
Subsequently, the temperature reducing program executed by the control unit 12 shown in FIG. 1 will be described with reference to the flowchart of FIG. The control unit 12 repeatedly executes the process shown in the flowchart of FIG. 2 at regular intervals.

First, the control unit 12 determines whether or not flash steam is generated by the drain discharged from the separator 6 (step S1). That is, the control unit 12 determines whether or not the detection vibration signal captured through the reception unit 16 indicates vibration peculiar to the flash vapor. Vibration data peculiar to flash steam is stored in the memory 14 of the control device 12, and when the detected vibration signal and the vibration data match, the detected vibration signal is grasped as the detected flash signal and the flash steam is generated. Judge.

It should be noted that the vibration data peculiar to the flash vapor may be stored as a band having a constant width quantitatively, and when the detected vibration signal is within this range, it may be determined that the flash vapor is generated.

When the flush steam is generated by the drain discharged from the separator 6, as described above, it can be determined that the amount of the cooling water injected into the superheated steam is appropriate, so that the control unit 12 processes it. Finish (YES judgment in step S1). On the other hand, when flash steam is not generated, the amount of water for cooling to the superheated steam is inappropriate, and it is recognized that either excessive or insufficient water is injected, so the amount of water injected. Perform the processing after step S2 to adjust (NO judgment in step S1).

First, the control unit 12 determines whether or not the detected temperature of the drain discharged from the separator 6 is lower than the reference temperature a (step S2). The reference temperature a is the temperature of the drain when the amount of the cooling water injected into the superheated steam is appropriate, and the data of the reference temperature a is stored in the memory 14 of the control device 12 in advance. The control unit 12 compares the reference temperature a with the detected temperature to make a determination. It should be noted that the reference temperature a may be stored as a band having a constant width quantitatively, and if it falls below this range, it may be determined that the detection temperature is smaller than the reference temperature a.

If it is determined in step S2 that the drain detection temperature is smaller than the reference temperature a (YES determination in step S2), in step S3, it is further determined whether or not the drain detection temperature is higher than the reference temperature b (step). S3). The reference temperature b is the temperature of the drain when the minimum amount of drain is generated. The data of the reference temperature b is stored in the memory 14 of the control device 12 in advance. The control unit 12 compares the reference temperature b with the detected temperature to make a determination. The reference temperature b may be stored as a band having a constant width quantitatively, and when it is below this range, it may be determined that the detected temperature is larger than the reference temperature b.

As described above, when the drain detection temperature is smaller than the reference temperature a and larger than the reference temperature b (YES judgment in step S3), the amount of water injected into the cooler 2 is larger than the appropriate amount due to excessive water injection. Since it is recognized that there is, the control unit 12 gives a closing signal to the water injection valve 4 through the line 30, closes the water injection valve 4 by a predetermined opening / closing amount, and reduces the water injection amount by a certain amount (step S5). After that, the process returns to step S1, the drain detection temperature rises until the reference temperature a is reached, and the process is repeated until flash steam is generated.

On the other hand, if it is determined in step S2 that the drain detection temperature is above the reference temperature a (NO determination in step S2), it is recognized that the amount of water injected into the cooler 2 is less than the appropriate amount. Therefore, the process proceeds to step S6, and the control unit 12 gives an open signal to the water injection valve 4 through the line 30, opens the water injection valve 4 by a predetermined opening / closing amount, and increases the water injection amount by a certain amount (step S6). After that, the process returns to step S1, the drain detection temperature drops until the reference temperature a is reached, and the process is repeated until flash steam is generated.

Further, when the drain detection temperature is determined to be equal to or lower than the reference temperature b in step S3 (NO determination in step S3), it means that the drain detection temperature is lower than a constant value. That is, since the flash steam is not generated and the drain temperature is low, it is determined that the superheated steam has not been sent to the cooler 2, and the water injection is stopped (step S4).

By repeating the above process, it is confirmed that the amount of water injected into the thermostat 2 is optimized and that flash steam is generated by the drain discharged from the separator 6 (step S1), and the temperature reduction program is terminated.

[Second Embodiment]
Next, a second embodiment of the steam temperature reduction system and the steam temperature reduction method according to the present application will be described. In the first embodiment, as described above, in the memory 14 of the control device 12, the vibration data of the ultrasonic wave peculiar to the generation of the flash steam and the drain when the amount of the cooling water injected into the superheated steam is appropriate in advance. The reference temperature a of was memorized. Here, depending on the installation status of the heater 2 and the separator 6, even if the amount of warming water injected into the superheated steam is appropriate due to the influence of the surrounding environment, the peculiar ultrasonic waves associated with the generation of flash steam are generated. It does not occur, and there is a possibility that a peculiar vibration different from the vibration related to the generation of flash vapor is generated.

Therefore, in the present embodiment, after the heater 2 and the separator 6 are actually installed, an appropriate amount of cooling water is supplied to the superheated steam, and the vibration and drain temperature actually generated at that time are measured. These individual measured data are measured and stored in the memory 14. Then, after that, these measured data are compared with the detected vibration (step S1 in FIG. 2), and are compared with the detected temperature (steps S2 and S4 in FIG. 2) to control the temperature reduction.

In addition, the basic configuration of the system in the present embodiment and the basic processing contents of the program related to temperature reduction are the same as the block diagram of FIG. 1 and the flowchart of FIG. 2 shown in the first embodiment.

[Other embodiments]
In each of the above-described embodiments, the monitoring sensor 25 has a function of detecting both vibration and temperature, and detects vibration and temperature at the same location. However, a sensor for vibration detection and a sensor for temperature detection are detected. May be prepared separately and then attached to different locations for detection.

Further, in each of the above-described embodiments, both excessive water injection and insufficient water injection are detected and controlled so that the amount of water injection is appropriate, but control is performed by focusing on either excessive water injection or insufficient water injection. You can also.

The steam deheating system and the steam deheating method according to the present application are not limited to the configurations exemplified in each of the above-described embodiments, and vibrations on the steam transfer path of the system for deheating superheated steam are detected. , Other configurations can be adopted as long as the configuration controls the water injection amount based on this.

2: Thermostat 4: Water injection valve 6: Separator 10: Control device
12: Control unit 14: Memory 16: Receiver unit 25: Monitoring sensor

Claims (3)

A temperature-reducing means that produces a de-heated steam by supplying a de-heating liquid to the superheated steam and mixing it.
Separation means, which extracts and separates a liquid from the temperature-reducing vapor generated by the temperature-reducing means.
Vibration detection means, which detects vibration caused by evaporation of the liquid extracted by the separation means and outputs a vibration signal.
A control means that controls the supply amount of the cooling liquid based on the vibration signal,
A steam cooling system characterized by being equipped with. In the steam temperature reduction system according to claim 1 ,
A temperature detection means that detects the temperature of the liquid extracted by the separation means and outputs a temperature signal.
Equipped with
The control means controls the supply amount of the cooling liquid based on the vibration signal and the temperature signal.
A steam cooling system characterized by that. A liquid for cooling is supplied to the superheated steam and mixed to generate the cooled steam.
The liquid is extracted and separated from the generated deheated steam and separated.
Detects vibration caused by evaporation of the extracted liquid and outputs a vibration signal.
Control the supply of cooling liquid based on the vibration signal,
A method of reducing the temperature of steam, which is characterized by that.

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