JP2013040576A - Steam system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a long service life and an efficient operation of an apparatus by promptly and accurately detecting steam load to control the supply of steam to a steam engine, and by detecting and reducing start-stop frequencies of the steam engine and a device driven by the same.SOLUTION: The system includes a steam engine 3 for generating power by using steam. Steam is supplied to a second steam header 8 to which steam depressurized after being used by the steam engine 3 is supplied even when not the steam engine 3 but a bypass passage 13 is employed. The bypass passage 13 is provided with a pressure reducing valve 14. A flow rate of steam passing through the bypass passage 13 is detected by a steam flowmeter 17. After the steam engine 3 stops, the system restarts the supply of steam to the steam engine 3 on the basis of a detected signal of the steam flowmeter 17.

Description

  The present invention relates to a steam system for driving an air compressor or the like using a steam engine.

  Conventionally, as disclosed in Patent Document 1 below, in a steam system that drives an air compressor or the like using a steam engine, the steam load is detected based on the steam pressure on the secondary side of the steam engine, and then sent to the steam engine. It is known to control steaming.

JP 2009-236103 A (Claim 1-7)

  However, although the steam load is detected based on the steam pressure in the invention described in Patent Document 1, the steam load may not always be detected quickly and accurately only by the steam pressure. Specifically, it is desirable to be able to quickly and accurately detect the presence of a steam load when determining a return condition for restarting after stopping the steam engine due to an increase in the steam pressure on the secondary side of the steam engine. . Thereby, the number of start and stop of the steam engine and the compressor can be reduced, and the life of the equipment can be extended and the operation can be performed efficiently.

  The problem to be solved by the present invention is to provide a steam system that can quickly and accurately detect the steam load and control the steam supply to the steam engine.

  The present invention has been made in order to solve the above-mentioned problems, and the invention according to claim 1 provides a steam engine that generates power using steam and decompressed steam after use in the steam engine. A bypass path for supplying steam to the location via the pressure reducing valve without passing through the steam engine, a steam flow meter for detecting the steam flow rate through the bypass path, and after the steam engine is stopped, And a controller that resumes steam supply to the steam engine based on a detection signal.

  According to the first aspect of the present invention, by detecting the flow rate of steam passing through the bypass passage with the steam flow meter, the steam load can be detected quickly and accurately, and steam supply to the steam engine can be controlled. .

  According to a second aspect of the present invention, a steam supply path to the steam engine and an exhaust steam path from the steam engine are connected by the bypass path, and the pressure reducing valve and the steam flow meter are connected to the bypass path. The steam system according to claim 1, wherein the steam system is provided.

  According to the second aspect of the present invention, by installing the steam flow meter in the bypass passage, the steam flow rate passing through the bypass passage can be detected quickly and accurately, and the steam supply to the steam engine can be controlled. .

  According to a third aspect of the present invention, an air compressor is driven by the steam engine, an air pressure sensor is provided in a compressed air passage from the air compressor, and the steam from the steam engine and the pressure reducing valve are A steam pressure sensor is provided so that the pressure of the steam combined with the steam can be detected, and steam supply to the steam engine is controlled based on detection signals of the steam flow meter, the air pressure sensor, and the steam pressure sensor. The steam system according to claim 1 or 2, wherein

  According to invention of Claim 3, in the system which manufactures compressed air with a steam engine, the steam supply to a steam engine can be controlled in consideration of compressed air load and steam load.

  The invention according to claim 4 is characterized in that, instead of detecting the flow rate by installing the steam flow meter, the flow rate is detected by a differential pressure before and after a fixed pressure loss portion provided in the bypass passage or a pipe before and after the bypass passage. The steam system according to any one of claims 1 to 3.

  According to invention of Claim 4, it can control by the differential pressure before and behind the fixed pressure-loss part of steam piping irrespective of a steam flow meter.

  According to a fifth aspect of the present invention, the pressure reducing valve has a movable part that accompanies the decompression of steam, and detects the flow rate by the movement of the movable part instead of detecting the flow rate by installing the steam flow meter. It is a steam system of any one of Claims 1-3 characterized by the above-mentioned.

  According to invention of Claim 5, it can control by the motion of the movable part of a pressure-reduction valve irrespective of a steam flowmeter.

  The invention according to claim 6 is characterized in that the flow rate is detected by the pressure of the fluid that operates the pressure reducing valve, instead of detecting the flow rate by installing the steam flow meter. The steam system according to the item.

  According to invention of Claim 6, it can control by the pressure of the working fluid of a pressure reducing valve irrespective of a steam flow meter.

  Furthermore, in the invention according to claim 7, instead of detecting the flow rate by installing the steam flow meter, the sound of the pressure reducing valve, the operation of a boiler that sends steam to the steam using equipment via the steam engine and the pressure reducing valve The steam flow rate is detected based on a situation, an operating condition of the steam-using facility, or a drain generation amount downstream of the steam engine and the pressure reducing valve. The steam system.

  According to the seventh aspect of the present invention, the control can be performed by the sound of the pressure reducing valve, the operation status of the boiler, the operation status of the steam using facility, or the amount of drain generation, without using the flow meter.

  According to the present invention, steam supply to a steam engine can be controlled by detecting the steam load quickly and accurately. Thereby, the number of start / stop of the steam engine and the compressor can be reduced, and the life of the device can be extended and the operation can be efficiently performed.

It is the schematic which shows one Example of the steam system of this invention.

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of the steam system 1 of the present invention.
A steam system 1 according to this embodiment includes a boiler 2, a steam engine 3, and a compressor 4.

  The steam engine 3 is a device that generates power using steam, and the type thereof is not particularly limited, but is, for example, a screw-type steam engine. The steam engine 3 is supplied with steam from the steam supply path 5 and discharges steam to the exhaust steam path 6.

  In the illustrated example, the steam from the boiler 2 is supplied to the first steam header 7, and the steam of the first steam header 7 is supplied to the steam engine 3 through the steam supply path 5. On the other hand, the steam from the steam engine 3 is supplied to the second steam header 8 through the exhaust steam path 6, and the steam of the second steam header 8 is supplied to various steam use facilities 9. In order to detect the pressure in the second steam header 8, a steam pressure sensor 10 is provided in the second steam header 8. The pressure in the first steam header 7 is maintained as desired by the boiler 2.

  A steam supply valve 11 is provided in the steam supply path 5 to the steam engine 3. By opening and closing the steam supply valve 11, it is possible to switch the operation of the steam engine 3. Further, by adjusting the opening degree of the steam supply valve 11, the steam supply amount to the steam engine 3 and thus the output of the steam engine 3 can be adjusted.

  A check valve 12 is provided in the exhaust steam path 6 from the steam engine 3. The check valve 12 can prevent the steam from flowing back to the steam engine 3 via the exhaust steam passage 6 when the steam engine 3 is stopped.

  The first steam header 7 and the second steam header 8 are also connected via the bypass 13. In the case of the illustrated example, in the steam supply path 5 from the first steam header 7 to the steam engine 3, in the upstream portion from the steam supply valve 11, and in the exhaust steam path 6 from the steam engine 3 to the second steam header 8. The downstream portion of the check valve 12 is connected by a bypass 13.

  A pressure reducing valve 14 is provided in the bypass path 13. The pressure reducing valve 14 adjusts the opening / closing or opening degree so as to maintain the back pressure (downstream pressure) at a predetermined pressure. In the present embodiment, the pressure reducing valve 14 is mechanically operated by itself so as to maintain the back pressure at a predetermined pressure. However, in some cases, the pressure reducing valve 14 may be controlled based on the pressure detected by the vapor pressure sensor 10.

  In the steam engine 3 and the pressure reducing valve 14, the steam is decompressed. Therefore, the pressure in the second steam header 8 is lower than the pressure in the first steam header 7. Depending on the steam use equipment 9, the steam of the first steam header 7 or the second steam header 8 is supplied.

  The compressor 4 driven by the steam engine 3 is an air compressor in this embodiment. In this case, the compressor 4 sucks in outside air, compresses it, and discharges it. Compressed air from the compressor 4 is sent to various types of compressed air utilization equipment (not shown) via the compressed air passage 15. The compressed air passage 15 is provided with an air pressure sensor 16 that detects the pressure of the compressed air.

  Steam supply to the steam engine 3 is controlled based on a detection signal from the steam pressure sensor 10 and, if desired, a detection signal from the air pressure sensor 16. For example, it is controlled as follows. In the following, the compressed air load can be detected, for example, by monitoring the pressure detected by the air pressure sensor 16 and detecting that there is a compressed air load when the air pressure falls below the lower limit air pressure, and detecting no compressed air load when the air pressure exceeds the upper air pressure. Further, the steam load can be detected, for example, by monitoring the detected pressure of the steam pressure sensor 10 and detecting that there is a steam load when the steam pressure falls below the lower limit steam pressure, and detecting that there is no steam load when the steam pressure exceeds the upper limit steam pressure.

(A) When there is a compressed air load and a steam load, steam supply to the steam engine 3 is performed.
(B) When there is no compressed air load or steam load, steam supply to the steam engine 3 is stopped.
(C) When there is no compressed air load but there is a steam load, steam is supplied via the bypass 13 in a state where steam supply to the steam engine 3 is stopped.
(D) When there is a compressed air load but no steam load, compressed air is supplied by an electric compressor (not shown) in a state where steam supply to the steam engine 3 is stopped. Alternatively, in this case as well, steam supply to the steam engine 3 may be executed, and the compressor 4 may be driven by the steam engine 3.

  Here, the determination that there is a steam load can be determined by the following method in addition to the determination that the detection pressure of the vapor pressure sensor 10 is lowered to the lower limit vapor pressure. That is, the following can be mentioned as a method for determining that there is a steam load, including the case of using the steam pressure sensor 10. In some cases, it is difficult to detect the steam load quickly and accurately with the detected pressure of the steam pressure sensor 10. In this case, basically, the steam is circulated to the second steam header 8 via the bypass 13. The steam load is determined depending on whether or not there is.

(1) When the detected pressure of the vapor pressure sensor 10 is equal to or lower than the set pressure, it is determined that there is a vapor load. In addition, the installation location of the vapor pressure sensor 10 is sufficient if it is downstream from the pressure reducing valve 14, and it is not always necessary to be the second vapor header 8.

(2) A steam flow meter 17 is installed in the bypass passage 13 and the like, and the steam load is determined based on the steam flow rate passing through the bypass passage 13. At this time, if there is a steam flow rate greater than or equal to a predetermined value, it may be determined that there is a steam load. In FIG. 1, the steam flow meter 17 is installed on the upstream side of the branching path with the bypass path 13 in the steam supply path 5 from the first steam header 7 to the steam engine 3. A steam flow meter 17 may be installed at 13. At that time, the steam flow meter 17 may be installed on the upstream side of the pressure reducing valve 14 or may be installed on the downstream side. In addition, a steam flow meter 17 is disposed downstream of the check valve 12 in the exhaust steam path 6 from the steam engine 3 to the second steam header 8 (especially, the downstream side is better than the junction with the bypass path 13). May be installed.

(3) In the steam path from the first steam header 7 to the second steam header 8 via the bypass path 13, a differential pressure before and after the fixed pressure loss part (for example, the valve 18 or the orifice) is detected, and the differential pressure increases. The steam flow rate may be determined by

(4) The movement / movable amount (for example, lift amount) of the movable portion of the pressure reducing valve 14 (which is a movable portion associated with the decompression of steam, for example, a lift portion) is detected, and the steam flow rate is determined from the opening / closing state of the pressure reducing valve May be.

(5) The steam flow rate may be determined by the pressure of the fluid that operates the pressure reducing valve 14. For example, when the pressure reducing valve 14 is pneumatic, the diaphragm supply pressure inside the pressure reducing valve 14 may be detected, and the steam flow rate may be determined from the open / closed state of the pressure reducing valve 14.

(6) The steam flow rate may be determined from the sound of the pressure reducing valve 14. Specifically, the sound of the pipe in the vicinity of the throttle expansion portion of the pressure reducing valve 14 may be measured, and the steam flow rate may be determined from the opening / closing of the pressure reducing valve 14 by the generation of a high frequency sound.

(7) The steam load may be detected according to the operation status of the boiler 2. Specifically, the steam flow through the bypass 13 is determined based on the startup status of the boiler 2 that supplies steam to the second steam header 8 or the startup number and startup status of the boilers 2, 2. May be.

(8) The steam load may be detected according to the operation status of the steam using facility 9. Specifically, the steam load may be determined based on the operation signal of the steam using facility 9 that uses the steam in the second steam header 8 and the operation signal of the steam supply valve 19 to the steam using facility 9.

(9) The steam load may be detected from the amount of drain generated downstream from the steam engine 3 and the pressure reducing valve 14. Specifically, a steam trap 20 may be provided in a steam line (second steam header 8 in the illustrated example) on the downstream side of the pressure reducing valve 14, and the amount of drain generated in the steam trap 20 may be detected to determine the steam load. .

(10) The steam load may be detected using a combination of two or more of the above (1) to (9). For example, (1) and (2) may be used in combination. When a plurality of methods are used in combination, detection of the steam load by each method may be used as an AND or OR condition. Moreover, you may use properly according to a situation, such as for the initial starting at the time of a driving | operation start, and the object for the re-restoration during driving | operation.

  In FIG. 1, the steam supply valve 11 is connected to the controller 21 in addition to the steam pressure sensor 10, the air pressure sensor 16, and the steam flow meter 17, and the controller 21 receives detection signals from the sensors 10, 16, and 17. Based on this, the steam supply valve 11 is controlled. For example, when the steam engine 3 is stopped due to various conditions, the controller 21 restarts steam supply to the steam engine 3 based on detection signals of the steam flow meter 17 and / or the steam pressure sensor 10. Instead of detecting the flow rate by installing the steam flow meter 17, the configurations (3) to (9) may be employed. Further, regarding the control of steam supply to the steam engine 3, as described above, the compressed air load by the air pressure sensor 16 may be taken into consideration.

  According to the steam system 1 of the present embodiment, it is possible to determine the usage load of the decompressed steam (steam of the second steam header 8) by the above-described methods. As a result, the number of start / stop times of the steam engine 3 and the compressor 4 driven by the steam engine 3 can be reduced, and the life of the device can be extended and the loss at startup can be reduced.

  The steam system 1 of the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. For example, in the above embodiment, the compressor 4 is driven by the steam engine 3, but the device driven by the steam engine 3 is not particularly limited, and may be, for example, a pump or a blower.

DESCRIPTION OF SYMBOLS 1 Steam system 2 Boiler 3 Steam engine 4 Compressor 5 Steam supply path 6 Exhaust steam path 7 First steam header 8 Second steam header 9 Steam use equipment 10 Steam pressure sensor 11 Steam supply valve 12 Check valve 13 Bypass path 14 Depressurization Valve 15 Compressed air passage 16 Air pressure sensor 17 Steam flow meter 18 Valve 19 Steam supply valve 20 Steam trap 21 Controller

Claims (7)

A steam engine that generates power using steam;
A bypass path for supplying steam via a pressure reducing valve to a place where reduced pressure steam after use in this steam engine is supplied without passing through the steam engine;
A steam flow meter for detecting the steam flow rate through the bypass,
And a controller that resumes steam supply to the steam engine based on a detection signal of the steam flow meter after the steam engine is stopped. The steam supply path to the steam engine and the exhaust steam path from the steam engine are connected by the bypass path,
The steam system according to claim 1, wherein the pressure reducing valve and the steam flow meter are provided in the bypass path. An air compressor is driven by the steam engine,
An air pressure sensor is provided in the compressed air path from the air compressor,
A steam pressure sensor is provided so that the pressure of the combined steam of the steam from the steam engine and the steam from the pressure reducing valve can be detected,
The steam system according to claim 1 or 2, wherein steam supply to the steam engine is controlled based on detection signals of the steam flow meter, the air pressure sensor, and the steam pressure sensor. 4. Instead of detecting the flow rate by installing the steam flow meter, the flow rate is detected by a differential pressure before and after a fixed pressure loss part provided in the bypass passage or a pipe before and after the bypass passage. The steam system according to item 1. The pressure reducing valve has a movable part accompanying the pressure reduction of the steam,
The steam system according to any one of claims 1 to 3, wherein a flow rate is detected by a movement of the movable part instead of detecting a flow rate by installing the steam flow meter. The steam system according to any one of claims 1 to 3, wherein the flow rate is detected by a pressure of a fluid that operates the pressure reducing valve, instead of detecting the flow rate by installing the steam flow meter. Instead of detecting the flow rate by installing the steam flow meter, the sound of the pressure reducing valve, the operating status of the boiler that sends steam to the steam using facility via the steam engine and the pressure reducing valve, the operating status of the steam using facility, or The steam system according to any one of claims 1 to 3, wherein a steam flow rate is detected from a drain generation amount downstream of the steam engine and the pressure reducing valve.

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