JP2015102250A - Flash steam generator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flash steam generator which when an operation of the flash steam generator is stopped and a bypass valve is opened, can reduce influence of the stop and the opening on equipment and the like downstream of the bypass valve.SOLUTION: A flash steam generator 1 includes a flash tank 2, a recovery line 3, a supply line 4, a discharge line 5, and control means. The recovery line 3 is provided with a bypass line 6 connecting the recovery line 3 and the discharge line 4 while bypassing the flash tank 2, the bypass line 6 is provided with a bypass valve 61 opening and closing the bypass line 6, and the control means gradually opens the bypass valve 61 when an operation of the flash steam generator 1 is stopped.

Description

  The present invention relates to a flash steam generator that re-evaporates drain collected from an upstream steam utilization facility and separates it into flash steam and hot water, and supplies the flash steam to a downstream steam utilization facility. is there.

  Conventionally, as shown in Patent Documents 1 and 2, the flash steam generator is configured to collect the drain from the upstream steam utilization facility in the flash tank.

JP 2012-7762 A JP 2009-198038 A

  For this reason, when clogging occurs in the recovery line for recovering the drain to the flash tank due to impurities contained in the drain generated in the upstream steam utilization facility, there is a problem such as an increase in pressure in the recovery line. Arise. Therefore, in order to avoid the influence on the upstream steam utilization facility due to the pressure increase in the recovery line, it is necessary to take measures such as releasing the pressure on the upstream steam utilization facility side.

  Therefore, the present applicant provides a bypass line for bypassing the flash tank and connecting the recovery line and the discharge line from the flash tank in the recovery line for recovering the drain to the flash tank, and further bypassing the bypass line. An application for an invention for providing a bypass valve for opening and closing a line was filed.

  In such a flash steam generator, when the operation is stopped, the bypass valve is normally opened so that the drain of the recovery line can be effectively discharged. Here, when a large amount of drain remains on the upstream side of the bypass valve, it is also assumed that excessive pressure is applied to the equipment and the like on the downstream side of the bypass valve by opening the bypass valve.

  Accordingly, the present invention provides a flash steam generator that can alleviate the influence on equipment downstream of the bypass valve when the operation of the flash steam generator is stopped and the bypass valve is opened. With the goal.

  The present invention is a flash steam generator that re-evaporates the drain collected from the upstream steam utilization facility and separates it into flash steam and hot water, and supplies the flash steam to the downstream steam utilization facility. A flash tank that separates the drain into the flash steam and the hot water; a recovery line that recovers the drain into the flash tank; and the flash steam from the flash tank to the downstream steam utilization facility. A supply line; a discharge line for discharging the hot water from the flash tank; and a control means for controlling the operation of the flash steam generator. The recovery line includes the flash A bypass line is provided to bypass the tank and connect the recovery line and the discharge line. The bypass line is provided with a bypass valve that opens and closes the bypass line, and the control means gradually opens the bypass valve when the operation of the flash steam generator is stopped. It is characterized by becoming.

  According to the above configuration, since the control means is configured to gradually open the bypass valve when the operation of the flash steam generator is stopped, the device on the downstream side of the bypass valve when the bypass valve is opened. It is possible to relieve the pressure applied to the etc.

  The present invention preferably further comprises the following configuration.

  The flash steam generator is provided with a discharge valve whose opening degree is controlled based on the water level of the flash tank in the discharge line, and the control means stops the operation of the flash steam generator. Then, the discharge valve is temporarily fully opened.

  According to the above configuration, when the operation of the flash steam generator is stopped, the control means is configured to temporarily open the discharge valve, so when the bypass valve is opened, the control means Such pressure can be relieved.

  In short, according to the present invention, when the operation of the flash steam generator is stopped and the bypass valve is opened, it is possible to provide a flash steam generator that can alleviate the influence on equipment and the like on the downstream side of the bypass valve.

It is a schematic block diagram of the flash steam generator which concerns on embodiment of this invention.

(overall structure)
FIG. 1 is a schematic configuration diagram of a flash steam generator according to an embodiment of the present invention. The flash steam generator 1 re-evaporates the drain collected from the upstream steam utilization facility 11 and separates it into flash steam and hot water, and supplies the flash steam to the downstream steam utilization facility 12. Yes. The upstream steam utilization facility 11 utilizes steam supplied from a boiler or the like as a heat medium, and is composed of, for example, a heat exchanger. The steam utilization facility 12 on the downstream side uses the steam supplied from the flash steam generator 1 as a heat medium, and is composed of, for example, a heat exchanger.

  The flash steam generator 1 includes a flash tank 2 that separates drain recovered from the upstream steam utilization facility 11 into flash steam and hot water, a recovery line 3 that recovers drain to the flash tank 2, and flash from the flash tank 2. A supply line 4 for supplying steam to the steam utilization facility 12 on the downstream side and a discharge line 5 for discharging hot water from the flash tank 2 are provided. The supply line 4 is provided with a supply valve 41 for opening and closing the supply line 4, and the discharge line 5 is provided with a discharge valve 51 for opening and closing the discharge line 5.

  The recovery line 3 is provided with a strainer 31 for filtering impurities contained in the drain from the steam utilization facility 11 on the upstream side. In the recovery line 3, on the upstream side of the strainer 31 and downstream of the upstream steam utilization facility 11, a bypass line that bypasses the flash tank 2 and connects the recovery line 3 and the discharge line 5. 6 is provided. The bypass line 6 is provided with a bypass valve 61 for opening and closing the bypass line 6. The flash steam generator 1 includes control means (not shown) that controls the operation of the flash steam generator 1.

  The bypass valve 61 is an electric valve, and prevents the drain from flowing into the flash tank 2 when the operation of the flash steam generator 1 is stopped (when the operation switch is turned off), that is, the flash steam. In order to protect the generator 1, it is automatically opened when the operation switch is turned off. Further, the bypass valve 61 is of a battery drive type so as to be automatically opened even when the power is cut off at the time of a power failure or the like. The bypass valve 61 is gradually opened by the attached electric motor when the operation switch is turned off. Further, even when the power is shut off, the battery is gradually opened by battery driving.

  The bypass line 6 is provided with a manual valve 62 that bypasses the bypass valve 61 in order to inspect and care for the bypass valve 61. The manual valve 62 is, for example, a ball valve.

  The flash tank 2 includes a water level sensor 21 and a float switch 22 as water level detection means for detecting the water level of the flash tank 2. The control means is a discharge valve 51 provided in the discharge line 5 so that the water level of the flash tank 2 detected by the water level sensor 21 is within a predetermined range (between the first reference value L1 and the second reference value L2). The degree of opening is controlled. The discharge valve 51 is an electric valve. Further, the control means opens the bypass valve 61 when the water level of the flash tank 2 detected by the water level sensor 21 is equal to or higher than the first alarm value A1 exceeding the predetermined range. The control means closes the bypass valve 61 when a predetermined time elapses after the bypass valve 61 is opened.

  Further, the control means opens the bypass valve 61 when the water level of the flash tank 2 detected by the float switch 22 becomes equal to or higher than the second alarm value A2 exceeding the first alarm value A1. In this case, the control means does not close the bypass valve 61 with the passage of a predetermined time.

  In the bypass line 6, pressure detection means (pressure sensor 32) that detects the pressure of the recovery line 3 on the upstream side of the strainer 31 is provided on the upstream side of the strainer 31. In the present embodiment, the pressure sensor 32 is provided in the bypass line 6, but may be provided in the recovery line 3. The control means opens the bypass valve 61 when the pressure in the recovery line 3 increases due to clogging of the strainer 31 and the pressure sensor 32 detects a predetermined pressure (first set pressure) or more.

  The control means gradually opens the bypass valve 61 when the operation of the flash steam generator 1 is stopped. As described above, when the operation of the flash steam generator 1 is stopped, the bypass valve 61 is gradually opened by the attached electric motor. As specific means for gradually opening the bypass valve 61, the time required for the normal bypass valve 61 to take from the fully closed state to the fully open state (for example, about 1 to 2 seconds) is more time (for example, about 5 seconds or more). It is conceivable that the fully opened state is applied.

  Furthermore, the control means is configured to fully open the discharge valve 51 when the operation of the flash steam generator 1 is stopped. By fully opening the discharge valve 51, the pressure applied to the discharge valve 61 and the like when the bypass valve 61 is opened can be relieved.

  The flash steam generator 1 operates as follows.

  In the steam utilization facility 11 on the upstream side, a part of the steam that has been used as a heat medium and has lost its latent heat is condensed and discharged as a drain. The discharged drain is sent to the flash tank 2 through the recovery line 3. Impurities and the like contained in the discharged drain are filtered by the strainer 31 provided in the recovery line 3. In general, the bypass valve 61 is closed, and the drain discharged from the upstream steam utilization facility 11 is sent to the flash tank 2 in its entirety.

  The flash tank 2 re-evaporates the drain received from the upstream steam utilization facility 11 and separates it into flash steam and hot water. The flash steam generated in the flash tank 2 is supplied to the downstream steam utilization facility 12 via the supply line 4.

  The hot water generated in the flash tank 2 is discharged to an open tank (not shown) or the like via the discharge line 5. The opening of the discharge valve 51 provided in the discharge line 5 is adjusted based on the detection result of the water level by the water level sensor 21 provided in the flash tank 2, and as a result, the water level of the flash tank 2 is adjusted. Is controlled to be positioned between the first reference value L1 and the second reference value L2.

  When the flash steam generator 1 is in operation, when the water level sensor 21 detects that the water level of the flash tank 2 is equal to or higher than the first alarm value A1, the control means opens the bypass valve 61 in the fully closed state. Thereby, since the water level of the flash tank 2 falls, the control means closes the bypass valve 61 when a predetermined time elapses after the bypass valve 61 is opened.

  When the float switch 22 detects that the water level of the flash tank 2 is equal to or higher than the second alarm value A2 while the flash steam generator 1 is operating, the control means opens the bypass valve 61. In this case, since the water level of the flash tank 2 is equal to or higher than the second alarm value A2, it is assumed that the water level is increased due to a trouble on the flash steam generator 1 side rather than an instantaneous increase in the drain amount. The For this reason, the control means does not return the bypass valve 61 to the closed state, but maintains the fully open state.

  Further, when the flash steam generator 1 is in operation, when the pressure sensor 32 detects the first set pressure or more, the control means fully opens the bypass valve 61 in the fully closed state. Then, the collection of the drain is switched to the collection using an open tank (not shown) or the like. At this time, the flash steam generator 1 is stopped due to the interlock. The on-site apparatus manager investigates the cause of the pressure increase (clogging of the strainer 31 and the like), eliminates it, resets the interlock, and puts the flash steam generator 1 into operation again.

  When the operation of the flash steam generator 1 is stopped, the control means gradually opens the bypass valve 61 and simultaneously opens the discharge valve 51 temporarily. That is, the discharge valve 51 is once fully opened when the operation of the flash steam generator 1 is stopped, but is closed after the bypass valve 61 that is gradually opened is fully opened. Note that the control means can perform this control also when the pressure sensor 32 detects the first set pressure or higher as described above.

  According to the flash steam generator 1 having the above-described configuration, the following effects can be exhibited.

(1) When the operation of the flash steam generator 1 is stopped, the control means gradually opens the bypass valve 61. Therefore, when the bypass valve 61 is opened, It is possible to relieve pressure applied to equipment.

(2) When the operation of the flash steam generator 1 is stopped, the control means temporarily opens the discharge valve 51. Therefore, when the bypass valve 61 is opened, the discharge valve 51, etc. Can be relieved.

(3) When the pressure sensor 32 detects the first set pressure or higher, the control means opens the bypass valve 61 provided in the bypass line 6, so that the upstream side due to the pressure increase in the recovery line 3 The influence on the steam utilization equipment 11 can be avoided.

(4) Since the bypass valve 61 is a battery-driven valve, it can be set to automatically open even when the power is shut off such as a power failure. In addition, when the power is shut off such as a power failure, the bypass valve 61 can be easily opened gradually by the battery.

(5) When the water level of the flash tank 2 detected by the water level sensor 21 is equal to or higher than the first alarm value A1, the control means opens the bypass valve 61. 11 can cope with an instantaneous increase in drain amount. In order to cope with an instantaneous increase in the drain amount, it is not necessary to increase the pipe diameter or valve of the flash steam generator 1, and the flash steam generator 1 can be rationally designed.

(6) Since the control means opens the bypass valve 61 for a predetermined time and then closes it, the drain can be smoothly received in the flash tank 2 after dealing with an instantaneous increase in the drain amount.

(7) When the water level of the flash tank 2 detected by the float switch 22 is equal to or higher than the second alarm value A2 exceeding the first alarm value A1, the cause is more than an increase in the water level due to an instantaneous increase in drain amount. It is assumed that the water level is increased due to trouble on the flash steam generator 1 side. For this reason, the control means maintains the fully open state without returning the bypass valve 61 to the closed state. As a result, the flash steam generator 1 can be smoothly shifted to inspection and maintenance.

  The bypass valve 61 can also be provided as a three-way valve at the connection point between the recovery line 3 and the bypass line 6 according to the embodiment. By switching the three-way valve, it is possible to control whether to maintain the flow to the flash tank 2 via the recovery line 3 or to switch to the flow to the bypass line 6.

  In the above embodiment, the flash steam generator 1 includes one flash tank 2, but the flash tank is not limited to one, and may include a plurality of flash tanks. In that case, the bypass line and the bypass valve may be provided for each flash tank, or may be provided one by one for the entire flash steam generator.

  In the above embodiment, the flash tank 2 serves as a water level detection means for detecting the water level of the flash tank 2, the water level within the predetermined range (first reference value L1 and second reference value L2) and the first alarm value A1. Although the water level sensor 21 to detect and the float switch 22 to detect the water level of the second alarm value A2 are provided, only the water level sensor or only the float switch may be provided as the water level detection means. In this case, the water level within the predetermined range, the water level of the first alarm value, and the water level of the second alarm value are detected by the water level sensor or the float switch.

  In the said embodiment, if the water level sensor 21 detects that the water level of the flash tank 2 is more than 1st alarm value A1, a control means will open the bypass valve 61 in a fully-closed state, and if predetermined time passes after that. The bypass valve 61 is closed. However, the control means closes the bypass valve 61 when the predetermined time has not elapsed and the water level of the flash tank 2 is equal to or lower than the predetermined value, for example, the second reference value L2 (and higher than the first reference value L1). You may do it. Even in this configuration, the drain can be smoothly received in the flash tank 2 after dealing with the instantaneous increase in the drain amount. The control means opens the bypass valve 61 when the water level of the flash tank 2 detected by the float switch 22 is equal to or higher than the second alarm value A2 exceeding the first alarm value A1, but in this case As in the above embodiment, the bypass valve 61 is not closed due to a drop in the water level of the flash tank 2.

  The present invention is not limited to the configuration described in the above embodiment, and can include various modifications that can be considered by those skilled in the art without departing from the content described in the claims.

  In the present invention, when the operation of the flash steam generator is stopped and the bypass valve is opened, it is possible to provide a flash steam generator that can alleviate the influence on equipment downstream of the bypass valve. The above utility value is great.

DESCRIPTION OF SYMBOLS 1 Flash steam generator 2 Flash tank 21 Water level sensor 22 Float switch 3 Recovery line 31 Strainer 32 Pressure sensor 4 Supply line 41 Supply valve 5 Discharge line 51 Discharge valve 6 Bypass line 61 Bypass valve 62 Manual valve 11 Upstream steam utilization equipment 12 Downstream steam utilization equipment

Claims (2)

A flash steam generator that re-evaporates the drain collected from the upstream steam utilization facility and separates it into flash steam and hot water, and supplies the flash steam to the downstream steam utilization facility,
A flash tank for separating the drain into the flash steam and the hot water;
A collection line for collecting the drain into the flash tank;
A supply line for supplying the flash steam from the flash tank to the downstream steam utilization facility;
A discharge line for discharging the hot water from the flash tank;
Control means for controlling the operation of the flash steam generator, and
The recovery line is provided with a bypass line that bypasses the flash tank and connects the recovery line and the discharge line.
The bypass line is provided with a bypass valve for opening and closing the bypass line,
The said control means is a flash steam generator characterized by opening the said bypass valve gradually, when the operation | movement of the said flash steam generator is stopped.
The flash steam generator includes, in the discharge line, a discharge valve whose opening degree is controlled based on the water level of the flash tank,
2. The flash steam generator according to claim 1, wherein when the operation of the flash steam generator is stopped, the control means temporarily opens the discharge valve. 3.

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