This application claims priority to and the benefit of German Patent Application No. 102018132811.7 filed on Dec. 19, 2018. The disclosure of the above application is incorporated herein by reference.
The present disclosure relates to water-injection systems for power plants for injecting water into a steam system.
The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
In gas and/or steam power plants, water is injected into a steam system when, as the turbine is being started up, the steam is not yet hot enough or when, as the turbine is being powered down, the steam has to be cooled. The quantity of water is metered via an upstream valve. This metering valve is usually configured in the form of a spindle valve and is opened and/or closed via a stepping motor.
WO2018/117957A1 discloses an attemperator comprising a pipe, a pipe casing and an injection system for introducing water into the pipe for the purpose of cooling steam.
The present disclosure addresses the issues related to injection systems for introducing water into a steam system for the purpose of cooling steam and other issues related to water-injection systems.
This section provides a general summary of the disclosure and is not a comprehensive disclosure of its full scope or all of its features.
In one form of the present disclosure a water-injection system for power plants and for injecting water into a steam system comprises a supply unit, a metering unit and an injection unit. The supply unit is configured to provide water to the metering unit. The metering unit is in the form of an electrically actuable system and is configured to meter a quantity of water to be injected into the steam system and to provide a quantity of water to the injection unit. The injection unit is configured to introduce the quantity of water into the steam system.
In some variations of the present disclosure, the injection pressure is greater than a steam pressure in the steam system. In at least one variation the injection pressure is at least 50 bar greater than the steam pressure in the steam system. For example, in some variations the steam pressure in the steam system is at least 50 bar, and in at least variation the steam pressure is at least 100 bar, and the water injection pressure is at least 50 bar greater than the steam pressure of 50 bar or 100 bar.
The metering unit of the water-injection system comprises at least one metering valve and a servo valve. The metering valve meters the quantity of water to be injected into the steam system and is actuated by the servo valve such that flexible control of water injection quantities is provided. The metering valve can be controlled servo-hydraulically and the servo valve can be configured with electromagnetic and/or piezoelectric actuators.
In some variations the injection unit comprises a water-injection valve and an injection line. The injection unit is connected to the metering unit via the injection line such that the quantity of water metered by the metering unit is introduced into the steam system through the water-injection valve.
In at least one variation, the injection line of the water-injection system is configured such that the water-injection valve is spaced apart from the metering valve and the servo valve, and overheating of the metering valve and/or of the servo valve is reduced or prevent. This arrangement of the water-injection valve, metering valve and servo valve reduces or prevents the likelihood of failure of the metering valve and/or of the servo valve on account of excessively high temperatures. In some variations the distance between the water-injection valve and metering valve and the servo valve is at least 10 cm, for example at least 30 cm or at least at least 50 cm.
In some variations of the present disclosure, the water-injection system comprises a control device configured to:
provide the water via the supply unit,
initiate the water-injection operation by actuation of the metering unit, and
terminate the water-injection operation by deactivation of the metering unit.
Accordingly, it should be understood that the control device provides a dynamic and precise metering of the quantity of water to be injected into the steam.
In another form of the present disclosure, a water-injection system for cooling steam in a power plant comprises a supply unit, a metering unit, an injection unit, and an injection line extending between the metering unit and the injection unit. The supply unit comprises a pump and a storage volume, and the pump is configured to pump water into the storage volume at a predefined pressure. The metering unit comprises a metering valve and a servo valve, and the servo valve is configured to be electromagnetically actuated into an open position such that water flows from the storage volume through the metering valve and into the injection line. The injection unit comprises a water-injection valve configured to open when the metering valve is open such that water flows from the injection line and through the injection valve into a steam system with steam. In some variations, metering unit includes electromagnetic actuators that electromagnetically actuate the servo valve from a closed position to the open position. In such variations, the metering valve can be configured to move from a closed position to an open position when the servo valve moves from the closed position to the open position.
In at least one variation the metering valve is spaced apart from the water-injection valve by more than 10 centimeters and/or the water-injection valve is positioned at an elevated height relative to the metering valve. For example, in one variation the metering valve is spaced apart from the water-injection valve by more than 30 centimeters and the water-injection valve is positioned at an elevated height relative to the metering valve.
In still another form of the present disclosure, a water-injection system for injecting water into a steam system of a power plant and cooling steam in the steam system includes a supply unit comprising a storage container, a filter, a storage volume and a pump. The water-injection system also includes a metering unit in fluid communication with the supply unit and comprising a metering valve, a servo valve, a restrictor and a valve slide, and an injection unit comprising a spring and a water injection valve. The pump is configured to pump water from the storage container to the metering unit and the servo valve is configured to be electromagnetically actuated into an open position. Also, the metering valve is configured to move from a closed position to an open position when the servo valve is actuated into the open position and via the water pumped from the storage container to the metering unit such that water flows from the metering unit to the injection unit. In at least one variation of the present disclosure, the water injection valve is configured to move from a closed position to an open position via the water flowing from the metering unit to the injection unit such that water is injected into the steam system of the power plant and steam in the steam system is cooled.
In some variations, the water-injection valve is positioned at an elevated height relative to the metering valve and/or the metering valve is spaced apart from the water-injection valve by more than 50 centimeters.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
In order that the disclosure may be well understood, there will now be described various forms thereof, given by way of example, reference being made to the accompanying drawings, in which:
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
Referring to
The metering unit 6 comprises at least one metering valve 8 and a servo valve 17. Via a restrictor 15, a hydraulic fluid, for example water, passes into a control space 14 on an end side or an end (−x direction) of a valve slide 24 shown in
As shown in
The injection line 9 is configured such that the injection unit 10 is spaced apart by a sufficient extent from the metering valve 8 and the servo valve 17. This advantageously achieves the situation where there is no overheating of the metering valve 8 and/or of the servo valve 17. Particularly, in some variations electromagnetic actuators 22 (
In some variations of the present disclosure, the water-injection valve 12 is arranged above (+y direction) the metering valve 8 and the servo valve 17, and therefore the water-injection valve 12 is at a higher geodetic height than the metering valve 8 and the servo valve 17. It should be understood that such an arrangement reduces or avoids the occurrence of a so-called heat pipe since steam bubbles which occur on the water-injection valve 12, on account of buoyancy, do not reach the metering valve 8 and/or the servo valve 17.
Referring particularly to
In at least one variation the injection unit 10 comprises a restrictor 7 as shown in
In some variations, the supply unit 1 comprises a storage container 21, a filter 3, a suitable storage volume 5 and a pump 2. The supply unit 1 is configured to store water in the storage volume 5 at a pressure advantageous for the water-injection system and to make this water available to the metering unit 6. The pump 2 takes in water from the storage container 21, via the filter 3, and delivers it into the storage volume 5. The pressure in the storage volume 5 is higher than the pressure in the steam system 25 and the pressure difference is adjusted via a pressure regulator 4. The pressure can be regulated by suitable control of the pump 2. Relatively small droplets resulting from the higher pressure in the storage volume 5 allow a relatively large surface area and relatively quick evaporation of the water entering the steam system 25 and therefore relatively quick mixing and cooling of the steam. For an advantageous reduction in the droplet diameters, the difference in pressure between the pressure in the storage volume 5 and the pressure in the steam system 25 is at least 10 bar, preferably ranging from 20-80 bar, particularly preferably ranging from 40-60 bar.
Referring particularly to
Referring now to
The control device here initiates the water-injection operation at S2, and terminates the water-injection operation at S3, on the basis of the state of the steam in the steam system 25. This provides for adaptive operation of the water-injection system, and therefore, in adaptation to the present state of the steam, injection is carried out with an appropriately metered quantity of water.
Possible advantages of the teachings of the present disclosure, on account of the electrical actuation of the metering unit, are advantageous dynamics and precise metering of the quantity of water which is to be injected into the steam. The electrical actuation takes place preferably electromagnetically or piezoelectrically.
Unless otherwise expressly indicated herein, all numerical values indicating mechanical/thermal properties, compositional percentages, dimensions and/or tolerances, or other characteristics are to be understood as modified by the word “about” or “approximately” in describing the scope of the present disclosure. This modification is desired for various reasons including industrial practice, material, manufacturing, and assembly tolerances, and testing capability.
As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A OR B OR C), using a non-exclusive logical OR, and should not be construed to mean “at least one of A, at least one of B, and at least one of C.”
The description of the disclosure is merely exemplary in nature and, thus, variations that do not depart from the substance of the disclosure are intended to be within the scope of the disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the disclosure.
In this application, the term “controller” or “control device” may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC); a digital, analog, or mixed analog/digital discrete circuit; a digital, analog, or mixed analog/digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared, dedicated, or group) that executes code; a memory circuit (shared, dedicated, or group) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system-on-chip.
Number | Date | Country | Kind |
---|---|---|---|
102018132811.7 | Dec 2018 | DE | national |
Number | Name | Date | Kind |
---|---|---|---|
3708976 | Berlyn | Jan 1973 | A |
3818699 | Pritchard | Jun 1974 | A |
3908382 | Stone, Jr. | Sep 1975 | A |
6804963 | Tomoiu | Oct 2004 | B1 |
20040124259 | Guezennec | Jul 2004 | A1 |
20060225672 | Donahue | Oct 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20200232346 A1 | Jul 2020 | US |