JP2013040591A - Device for controlling process steam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for controlling process steam capable of converting the pressure of the process steam from a low pressure to a high pressure and also capable of converting it from a high pressure to a low pressure.SOLUTION: Switching valves 5, 6, are mounted to an increased-pressure process steam supply pipe 2, and a branch pipe 7 is connected. The branch pipe 7 is connected to screw rotor parts 8, 24 of steam compressing and expansion machines 17, 4. A lower part of the screw rotor part 24 is connected to a reduced-pressure process steam supply pipe 3 by a communication pipe 11. The process steam is expanded and reduced in pressure by operating switching valves 5, 6, 15, 16, 21 to supply the process steam from the increased-pressure process steam supply pipe 2 to the steam compressing and expansion machines 17, 4. In contrast, the process steam is compressed and increased in pressure by supplying the process steam from the reduced-pressure process steam supply pipe 3 to the screw rotor parts 24, 8.

Description

 The present invention relates to a process steam control apparatus for supplying steam having different pressure values to a steam use location via a steam supply pipe. Here, the process steam indicates the steam supplied to the steam use location.

 The conventional process steam control device reduces the effective energy loss due to the steam supply to the process while supplying steam of different pressures and temperatures as process steam from the steam turbine, thereby improving the power of the steam plant. The efficiency can be improved.

 The conventional process steam control device can supply low-pressure steam exhausted from a back-pressure turbine as high-pressure process steam by a steam compressor driven by a motor. There is a problem that the pressure cannot be reduced and supplied as low-pressure process steam.

JP 5-65808

 The problem to be solved is to enable the process steam pressure value to be converted not only from low pressure to high pressure, but also from high pressure to low pressure.

 The present invention provides a process steam supply pipe for supplying steam having different pressure values to a steam use place, and a plurality of steam compression and expansion machines are arranged in at least one process steam supply pipe, A plurality of vapor compression and expansion machines are used, and a screw compressor is used as a vapor compressor. On the other hand, as a vapor expansion machine, a plurality of vapor compression and expansion machines are compressed using the reverse cycle of the screw compressor. And a switching valve for switching the connection positions of the plurality of vapor compression and expansion machines to a parallel state or a serial state.

  In the present invention, by arranging a plurality of steam compression and expansion machines in at least one process steam supply pipe, the process steam can be converted into high-pressure steam by compressing, and the process steam is expanded. Can be converted into low-pressure steam.

The block diagram of the control apparatus of the process steam of this invention.

  The process steam control apparatus according to the present invention has a plurality of steam compressors and expanders arranged in a process steam supply pipe. The steam compressors and expanders have been widely used as refrigeration, air conditioning, and gas compressors. The screw compressor that has been used is used as a steam compressor, while as a steam expander, by utilizing the reverse cycle of the screw compressor, i.e., by reversing the steam inlet and outlet of the screw compressor, It can be used as a steam expander by injecting high-pressure steam from the outlet side and allowing low-pressure steam that is expanded from the inlet side to flow down and flows down.

 In FIG. 1, a process steam supply pipe 1, a pressure-increasing process steam supply pipe 2, a decompression process steam supply pipe 3, a plurality of steam compression and expansion machines 4 and 17, and a heat exchanger 18 are used. The control device is configured.

  The process steam supply pipe 1 supplies process steam from a steam source (not shown) on the left side of the drawing to a steam use location (not shown) on the right side of the drawing.

 A branch pipe 7 is connected to the pressure-increasing process steam supply pipe 2 through switching valves 5 and 6. A vapor compression and expansion machine 17 is connected to the branch pipe 7 via a heat exchanger 18. In this embodiment, an example using a screw type vapor compression and expansion machine 17 is shown. The screw type vapor compression and expansion machine 17 is composed of a pair of left and right male and female screw type rotor parts 8 and a generator or electric motor part 9.

  The branch pipe 7 is arranged in a coil shape inside the heat exchanger 18, and the lower end is connected to the steam inlet of the screw rotor unit 8 with the lower branch 10. Although not shown, a high-temperature high-pressure steam pipe is connected to the upper part of the side surface of the heat exchanger 18, and the gas-liquid separator 12 is connected to the lower part of the heat exchanger 18 via a pipe line. An outlet pipe 13 is attached to the outlet side of the gas-liquid separator 12 and connected to the low-pressure process steam supply pipe 3.

The steam supplied to the screw-type rotor section 8 through the branch pipe 7 and the lower branch pipe 10 is heated by the high-pressure high-temperature steam from the high-temperature high-pressure steam pipe in the heat exchanger 18 to become superheated steam, and the screw-type rotor section. By being supplied to 8, as will be described later, when it expands and is depressurized, it becomes difficult for the steam to condense, and condensate generation can be prevented.

  The high-temperature and high-pressure steam deprived of heat in the heat exchanger 18 is partially condensed to condensate, and flows into the gas-liquid separator 12 as a mixed fluid of condensate and steam. Only the steam separated from the condensate by the gas-liquid separator 12 flows into the decompression process steam supply pipe 3 from the outlet pipe 13. On the other hand, the condensate separated from the steam by the gas-liquid separator 12 is removed from the system from the steam trap 14.

  The lower part of the screw-type rotor part 8 of the vapor compression and expansion machine 17 is connected to the three-way switching valve 20 and the decompression process steam supply pipe 3 via a communication pipe 19. The three-way switching valve 20 is provided with three-way switching ports 21, 22, and 23, respectively. The switching port 21 is connected to the pressure-increasing process steam supply pipe 2 by a pipe line 24, and the switching port 22 is connected to the other steam compression and expansion machine 4. This vapor compression and expansion machine 4 has the same configuration as the other vapor compression and expansion machine 17.

The communication pipe 11 is also connected to the decompression process steam supply pipe 3 through switching valves 15 and 16. The upper end of the communication pipe 11 is connected to the vapor compression and expansion machine 4.

  When reducing the pressure value of the process steam, the switching valve 5 of the pressure-increasing process steam supply pipe 2 is opened and the switching valve 6 is closed, and the switching valve 15 of the decompression process steam supply pipe 3 is closed and switched. The valve 16 is opened, and the steam from the process steam supply pipe 1 is supplied from the branch pipe 7 to the screw type rotor unit 8. The supply steam expands while rotating the screw-type rotor unit 8, is decompressed, and is supplied to the decompression process steam supply pipe 3. Moreover, the rotational driving force of the screw-type rotor unit 8 rotates the connected generator 9 to generate predetermined power.

  Further, steam from the process steam supply pipe 1 is supplied from the pipe line 24 through the switching ports 21 and 20 of the three-way switching valve 20 to the other steam compression and expansion machine 4, while rotating the screw type rotor unit 24. It expands, is decompressed, and is supplied to the decompression process steam supply pipe 3. In addition, the rotational driving force of the screw-type rotor unit 24 rotates the connected generator 25 to generate a predetermined power.

  Thus, by connecting a plurality of vapor compression and expansion machines 4 and 17 in parallel, a large amount of vapor from the process vapor supply pipe 1 can be decompressed to a predetermined value.

  When increasing the pressure value of the process steam, the switching valve 15 of the decompression process steam supply pipe 3 is opened and the switching valve 16 is closed, and the switching valve 5 of the pressure increasing process steam supply pipe 2 is closed and switched. The valve 6 is opened, and the steam from the process steam supply pipe 1 is passed through the communication pipe 11 from the lower part of the screw rotor section 24, that is, from the direction opposite to the above-described decompression and expansion, the screw rotor section 24. And the three-way switching valve 20 is operated to open the switching ports 22 and 23 and close the switching port 21, so that the steam from the steam compression and expansion machine 4 is transferred to the other steam compression and expansion machine 17. Supplied with. The screw-type rotor units 8 and 24 are rotationally driven by the electric motor units 9 and 25, and the process steam is compressed and increased to a predetermined pressure, and is supplied to the increased pressure process steam supply pipe 2.

  Thus, by connecting a plurality of steam compression and expansion machines 4 and 17 in series, the steam from the process steam supply pipe 1 can be increased to a higher pressure value.

  According to the present invention, the pressure value of the process steam can be reduced or increased, and the steam having a pressure corresponding to the use of the process steam can be quickly supplied.

1
Process steam supply pipe 2
Pressure increase process steam supply pipe 3
Depressurized process steam supply pipe 4,17
Vapor compression and expansion machine 5,6
Switching valve 8, 24
Screw type rotor unit 9, 25 Generator or electric motor unit 12 Gas-liquid separator 14 Steam trap 15, 16 Switching valve 18 Heat exchanger

Claims (1)

In the case where a process steam supply pipe for supplying steam having different pressure values to a place where steam is used is provided, a plurality of steam compression and expansion machines are arranged in at least one process steam supply pipe, and the plurality of steam The compressor and expander are screw compressors as steam compressors, while the steam expander uses the reverse cycle of the screw compressors to switch between compression and expansion of the multiple steam compressors and expanders. In addition, a process steam control device, wherein a switching valve for switching the connection positions of the plurality of steam compression and expansion machines to a parallel state or a serial state is attached.