JP4975424B2 - Steam waste heat recovery and decompression equipment - Google Patents

Description

 TECHNICAL FIELD The present invention relates to a steam waste heat recovery and decompression device that re-evaporates high-temperature condensate condensed with steam in a re-evaporation tank and reuses it as steam.

 In the conventional steam waste heat recovery and decompression device, a condensate supply pipe is connected to the re-evaporation tank, and a communication pipe is interposed in the steam ejector that sucks the vapor re-evaporated from the condensate in the re-evaporation tank. The re-evaporation tank is connected, and a pressure control valve is attached to this communication pipe. The re-evaporation vapor in the re-evaporation tank is sucked with a steam ejector and supplied to a predetermined steam use location. Waste heat recovery can be achieved.

  The conventional steam waste heat recovery and decompression device has a problem that the pressure of steam supplied from a steam ejector to a predetermined steam use location cannot be adjusted with high accuracy.

In the conventional steam waste heat recovery and decompression device, since the reevaporation tank and the steam ejector are connected via the communication pipe and the pressure control valve, the reevaporation tank is connected to the suction port of the steam ejector. As a result, the pressure loss in the pipes up to this point becomes large, and there has been a problem that the re-evaporated steam generated in the re-evaporation tank cannot be efficiently sucked by the steam ejector.
JP 2004-278871 A

  The problem to be solved is that the steam pressure supplied from the steam ejector that sucks the re-evaporated steam can be adjusted with high accuracy, and the pressure loss from the re-evaporation tank to the suction port of the steam ejector is minimized. Thus, a steam waste heat recovery and decompression device capable of efficiently sucking reevaporated steam with a steam ejector is obtained.

In the present invention, a condensate supply pipe is connected to a re-evaporation tank, and a steam ejector that sucks vapor re-evaporated from the condensate in the re-evaporation tank is connected, and steam for driving is supplied to the steam ejector. Attach a pressure control valve to the steam supply pipe, place at least two steam ejectors, connect the suction pipe to the outer peripheral surface of the suction chamber of the steam ejector, and between the suction pipe and the suction chamber of one steam ejector And the other steam ejector outlet side communicates with the two-way switching valve branched from the three-way switching valve, and at least two units are switched by the switching operation of the two-way switching valve and the three-way switching valve . The steam ejector connection position is switched to a parallel state or a serial state, and at least the suction port of the steam ejector is opened in the re-evaporation tank to perform the re-evaporation. The top of the tank, in which the pressure in the re-evaporation tank fitted with a pressure control valve which can be maintained at the set value.

  In the present invention, by attaching a pressure control valve to the steam supply pipe of the steam ejector, the steam pressure supplied from the steam ejector can be accurately adjusted, and the suction port of the steam ejector is opened in the re-evaporation tank. Thus, the pressure loss between the re-evaporation tank and the suction port of the steam ejector can be made substantially zero, and the re-evaporated vapor can be efficiently sucked by the steam ejector.

Further, the present invention attaches at least two steam ejectors and a flow path switching valve, and switches the connection positions of at least two steam ejectors to a parallel state or a serial state by switching the switching valve. Re-evaporated steam that varies from a small amount to a large amount can be achieved by placing the steam ejector in parallel when a large amount of intake steam is generated, and by connecting the steam ejector in series when the amount of intake steam is small. Can be inhaled quickly.

  The present invention uses a pressure control valve. If this pressure control valve can control and control the pressure, it is a conventionally known valve, for example, an automatic pressure control valve that combines a pressure sensor and a controller. Or a self-acting pressure control valve can be used.

  In FIG. 1, a re-evaporation tank 1, a condensate supply pipe 2 for supplying condensate to the re-evaporation tank 1, two steam ejectors 3 and 8 disposed in the re-evaporation tank 1, and steam ejectors 3 and 8 The pressure regulating valve 10 attached to the steam supply pipe 9 and the liquid pumping member 7 constitute a waste heat recovery and decompression device for steam.

The reevaporation tank 1 has a cylindrical sealed shape, and a condensate supply pipe 2 is connected to the upper part of the right side surface, and a condensate outlet pipe 5 is connected to the lower part of the left side surface. The condensate supply pipe 2 is connected to a condensate generation source such as a steam using device (not shown) through a valve 6 and a steam trap 23. On the other hand, the condensate outlet pipe 5 is connected to the liquid inlet 15 of the liquid pumping member 7 via a check valve 14. The check valve 14 only allows the liquid to flow from the re-evaporation tank 1 to the liquid pumping member 7, and does not allow the liquid to pass in the opposite direction.

Steam ejectors 3 and 8 are arranged inside the re-evaporation tank 1. A pressure control valve 10 is attached to a steam supply pipe 9 that supplies steam for driving to the steam ejectors 3 and 8. The steam supply pipe 9 is connected to a nozzle portion (not shown) in the suction chambers 12 and 13 of the steam ejectors 3 and 8. The suction pipe 11 is communicated with the outer peripheral surfaces of the suction chambers 12 and 13. A three-way switching valve 26 is interposed between the suction pipe 11 and the suction chamber 12. The outlet side of the steam ejector 8 communicates with the three-way switching valve 26 and the branched two-way switching valve 27 and check valve 28.

The steam ejectors 3 and 8 generate a predetermined suction force in the suction chambers 12 and 13 by the high-pressure steam supplied from the steam supply pipe 9, and the steam re-evaporated from the condensed water in the re-evaporation tank 1 The suction pipe 11 can suck.

The pressure control valve 10 attached to the steam supply pipe 9 uses a pressure sensor 25 attached to the secondary side of the steam supply pipe 9 in combination with a pressure controller (not shown). The pressure in the steam supply pipe 9 is detected by the pressure sensor 25, and the valve opening degree of the pressure control valve 10 is automatically controlled so as to reach the set pressure set by the pressure controller. The pressure of steam supplied from the secondary side to a steam use location (not shown) can be accurately adjusted to an arbitrary value.

A pipe 24 is connected to the upper part of the reevaporation tank 1 and a pressure control valve 4 is attached. The pressure control valve 4 is a self-acting primary pressure control valve. When the pressure in the reevaporation tank 1 exceeds the set pressure of the pressure control valve 4, the pressure control valve 4 is opened and the pressure in the reevaporation tank 1 is increased. By releasing the pressure, the pressure in the reevaporation tank 1 can be maintained at a set value.

The liquid pumping member 7 has a liquid inlet 15 and a liquid outlet 16, a high-pressure operating fluid inlet 17 and a high-pressure operating fluid outlet 18, and condensate is discharged to the liquid outlet 16 via a check valve 19. While connecting the pipe 20, the high-pressure steam pipe 21 is connected to the high-pressure operating fluid inlet 17. On the other hand, the high-pressure operating fluid discharge port 18 communicates with the upper part of the re-evaporation tank 1 through the pressure equalizing pipe 22.

The liquid pumping member 7 is disposed below the reevaporation tank 1. Further, the liquid pumping member 7 closes the high-pressure operating fluid introduction port 17 and opens the high-pressure operating fluid discharge port 18 when a float (not shown) disposed therein is located in the lower portion, and re-evaporation tank From 1, the condensate flows down into the liquid pumping member 7 through the check valve 14 and the liquid inlet 15. When condensate accumulates in the liquid pumping member 7 and a float (not shown) is located at a predetermined upper portion, the high-pressure operation fluid discharge port 18 is closed, while the high-pressure operation fluid introduction port 17 is opened, and the high-pressure steam pipe The steam for high-pressure pumping is caused to flow from 21 to the inside, so that the condensate accumulated therein is pumped to a predetermined location through the liquid outlet 16, the check valve 19 and the condensate discharge pipe 20.

  When the condensate is pumped and the liquid level in the liquid pumping member 7 is lowered, the high pressure operating fluid inlet 17 is closed again and the high pressure operating fluid outlet 18 is opened, so that the condensate is discharged from the liquid inlet 15. Flow down to the inside. By repeating such an operation cycle, the liquid pumping member 7 pumps the condensate from the reevaporation tank 1 to a predetermined location.

A portion of the condensate supplied from the condensate supply pipe 2 into the re-evaporation tank 1 is re-evaporated in the re-evaporation tank 1 and sucked into the suction chambers 12 and 13 of the steam ejectors 3 and 8. In this case, there is no member that obstructs the flow of reevaporated steam to the suction chambers 12 and 13 and increases the pressure loss. Therefore, the steam in the reevaporation tank 1 is efficiently in a state where the pressure loss is almost zero. The suction chambers 12 and 13 are sucked.

The steam ejectors 3 and 8 generate a predetermined suction force in the suction chambers 12 and 13 by the high-pressure steam supplied from the steam supply pipe 9, but when the amount of reevaporated steam sucked from the suction pipe 11 is large When the two-way switching valve 27 is opened and the three-way switching valve 26 is operated to connect the suction pipe 11 and the suction chamber 12, the connection positions of the two steam ejectors 3 and 8 are in a parallel state. The steam ejectors 3 and 8 can suck a large amount of re-evaporated vapor through the suction pipe 11.

When the amount of re-evaporated vapor sucked from the suction pipe 11 is small, the two-way switching valve 27 is closed and the three-way switching valve 26 is operated to connect the outlet side of the steam ejector 8 and the suction chamber 12 of the steam ejector 3. As a result of the communication, the connection positions of the two steam ejectors 3 and 8 are in series, and the steam sucked from the suction pipe 11 into the suction chamber 13 of the steam ejector 8 passes through the three-way switching valve 26 and is sucked into the steam ejector 3. It is sucked into the chamber 12 and discharged to the downstream side of the steam supply pipe 9.

The pressure control valve 4 attached to the upper line 24 of the reevaporation tank 1 causes the pressure in the reevaporation tank 1 to be a pressure state in which condensate can flow into the reevaporation tank 1 from the steam trap 23. That is, by setting the pressure in the re-evaporation tank 1 to a pressure state lower than the pressure in the condensate supply pipe 2 by a predetermined value, the condensate can surely flow down from the steam trap 23 to the re-evaporation tank 1. it can.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the Example of the waste heat recovery of steam and the pressure reduction device concerning this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Re-evaporation tank 2 Condensate supply pipe 3 Steam ejector 7 Liquid pressure feeding member 8 Steam ejector 9 Steam supply pipe 10 Pressure control valve 11 Suction pipe 12, 13 Suction chamber 14 Check valve 15 Liquid inlet 16 Liquid outlet 17 High pressure operation Fluid inlet 18 High pressure operation fluid outlet 20 Condensate outlet 23 Steam trap 24 Pipe 26 Three-way switching valve 27 Two-way switching valve 28 Check valve

Claims (1)

A steam supply pipe that connects a condensate supply pipe to a re-evaporation tank, and a steam ejector that sucks steam re-evaporated from the condensate in the re-evaporation tank, and supplies steam for driving to the steam ejector A pressure control valve is attached to the at least two steam ejectors, a suction pipe is connected to the outer peripheral surface of the suction chamber of the steam ejector, and a three-way switching valve is provided between the suction pipe and the suction chamber of one steam ejector. And the other steam ejector outlet side communicates with the two-way switching valve branched from the three-way switching valve, and at least two steam ejectors are connected by switching operation of the two-way switching valve and the three-way switching valve. The position is switched to the parallel state or the serial state, and at least the suction port of the steam ejector is opened in the re-evaporation tank to To, waste heat recovery and decompression device of the steam, characterized in that fitted with pressure control valve the pressure can be maintained at a set value in the re-evaporation tank.

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