JP5274900B2 - Steam waste heat recovery system - Google Patents

Description

 TECHNICAL FIELD The present invention relates to a steam waste heat recovery apparatus 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 system, a condensate supply pipe is connected to a re-evaporation tank, and a steam ejector that sucks the re-evaporated steam of the condensate in the re-evaporation tank is connected via a communication pipe. Connected to the evaporating tank, a pressure control valve is attached to this communication pipe, and a liquid pumping member is arranged below the re-evaporating tank. The re-evaporated vapor in the re-evaporating tank is sucked with a steam ejector It is possible to recover the waste heat of the steam by supplying it to the place where the steam is used.

In the above-mentioned conventional waste heat recovery apparatus for steam, when a large amount of re-evaporated steam is generated in a re-evaporation tank, for example, when a large amount of re-evaporated steam is generated, a single steam ejector cannot be inhaled. was there.
JP 2004-278871 A

  The problem to be solved is to obtain a waste heat recovery device for steam that can be quickly sucked even if the amount of sucked steam varies from a small amount to a large amount.

In the present invention, a condensate supply pipe is connected to a re-evaporation tank, and a steam ejector for sucking vapor re-evaporated from the condensate in the re-evaporation tank is connected. The screw-type compressor is composed of a screw-type rotor, a rotating unit that rotates the rotor, and a control unit that controls the number of revolutions. When the amount of steam is large, a large amount of re-evaporated steam can be sucked by increasing the rotation speed of the screw compressor and increasing the suction capacity, while the amount of re-evaporated steam in the re-evaporation tank is small. In the case of a small amount, the rotational speed of the screw compressor is lowered to reduce the suction capacity .

  According to the present invention, when a screw compressor is connected to the outlet side of the steam ejector, when a large amount of intake steam is generated, the screw compressor is increased in number of rotations to suck in a large amount of steam. In the case of a small amount, the re-evaporated vapor that fluctuates from a small amount to a large amount can be rapidly sucked by lowering the rotational speed of the screw compressor.

  The present invention uses a screw compressor, and as the screw compressor, one that can freely control the suction capacity by changing the rotation speed is suitable.

  In FIG. 1, a re-evaporation tank 1, a condensate supply pipe 2, a steam ejector 3, and a screw compressor 4 constitute a waste heat recovery device for steam.

  The steam ejector 3 includes a suction chamber 5 and a diffuser 6. A nozzle is built in the suction chamber 5 and is connected to a driving steam pipe 7. The upstream side of the driving steam pipe 7 is connected to a high-pressure steam source (not shown).

  A screw type compressor 4 is connected to the outlet side of the steam ejector 3. The screw-type compressor 4 includes a screw-type rotor, a rotating unit that rotates the rotor, and a control unit that controls the number of rotations. Connected to the outlet side of the screw compressor 4 is a steam supply pipe 8 for supplying re-evaporated steam, which has been pressurized to a predetermined pressure by the screw compressor 4, to a steam use location (not shown).

  The suction chamber 5 of the steam ejector 3 is connected to the upper part of the reevaporation tank 1 by a pipe 9. A check valve 10 that allows only the flow of steam from the reevaporation tank 1 to the suction chamber 5 side and prevents the flow of fluid in the opposite direction is attached to the conduit 9.

A condensate supply pipe 2 is connected to the left side surface of the reevaporation tank 1. The left end of the condensate supply pipe 2 is connected to a high temperature condensate source to supply high temperature condensate into the reevaporation tank 1. Steam re-evaporated from the high-temperature condensate in the re-evaporation tank 1 is sucked into the steam ejector 3, further pressurized by the screw compressor 4, and supplied from the steam supply pipe 8 to a predetermined steam use location. is there.

The bottom surface of the re-evaporation tank 1 is connected to a water ejector 13 of an ejector type vacuum pump 12 through a communication pipe 11. The ejector type vacuum pump 12 includes a water ejector 13, a cooling water tank 14, a circulation pump 15, and a connection circuit 16 connecting them. A cooling water supply pipe 17 for supplying cooling water into the tank 14 is connected to the cooling water tank 14. Moreover, a part of the connection circulation path 16 is branched, and the surplus water discharge pipe 18 for discharging surplus water is connected.

The steam ejector 3 generates a predetermined suction force in the suction chamber 5 by the high-pressure steam supplied from the driving steam pipe 7. If the amount of the re-evaporated steam in the re-evaporation tank 1 is large, A large amount of re-evaporated steam can be sucked by increasing the number of revolutions of the compressor 4 and increasing the suction capacity. On the other hand, if the amount of re-evaporated steam in the re-evaporator tank 1 is small, a screw compressor This can be dealt with by lowering the rotational speed of 4 to reduce the suction volume.

  Condensate that cannot be completely evaporated again at the bottom of the re-evaporation tank 1 is sucked into the water ejector 13 of the ejector vacuum pump 12 and reaches the cooling water tank 14.

BRIEF DESCRIPTION OF THE DRAWINGS The block diagram which shows the Example of the waste heat recovery apparatus of the steam which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Re-evaporation tank 2 Condensate supply pipe 3 Steam ejector 4 Screw type compressor 7 Drive steam pipe 8 Steam supply pipe 12 Ejector type vacuum pump 13 Water ejector 14 Cooling water tank 15 Circulation pump 16 Connection circuit

Claims (1)

A condensate supply pipe is connected to the re-evaporation tank, and a steam ejector that sucks steam re-evaporated from the condensate in the re-evaporation tank is connected, and a screw type compressor is connected to the outlet side of the steam ejector , The screw type compressor is composed of a screw type rotor, a rotating part that rotates the rotor, and a control part that controls the rotation number, and the amount of re-evaporated steam in the re-evaporating tank is reduced. If the amount of re-evaporated steam in the re-evaporation tank is small, the amount of re-evaporated vapor in the re-evaporation tank is small. A waste heat recovery system for steam, characterized in that the rotational speed of the screw compressor is lowered to reduce the suction capacity .

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