JP5302443B2 - Power generator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generation apparatus capable of suppressing a drain generated from steam upon generation. <P>SOLUTION: The power generation apparatus 20 generates electricity using supplied steam, and exhausts the steam used in generation. The power generation apparatus 20 includes: a positive displacement expander 22 that generates power in response to a displacement change of an expansion chamber 40 caused by a pressure of steam introduced to the expansion chamber 40; a generator 24 that is connected to the positive displacement expander 22 via a power transmission device 64 such that power from the positive displacement expander 22 is transmitted; and a drain prevention device 58 for preventing drain generated from the supplied steam by allowing the steam to pass through the positive displacement expander 22. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a power generator that drives a generator by a drive source that obtains power (driving force) from supplied steam, and more particularly to a power generator that drives a generator using a positive displacement expander as a drive source.

  The following power generation devices described in Patent Document 1 are known as power generation devices that perform power generation using an excess pressure difference of steam in a steam process in a factory or the like.

  This power generator includes a screw expander as a drive source that obtains power from steam supplied from an upstream steam source (boiler, etc.), and the screw expander so that the power is transmitted from the screw expander. And a generator to be connected. The screw expander is a positive displacement expander, and obtains rotational force (power) according to a change in volume of the expansion chamber due to the pressure of the steam introduced (supplied) into the expansion chamber.

  In this positive displacement expander, it is possible to efficiently convert the steam pressure difference between the upstream side (inlet) and the downstream side (outlet) of the positive displacement expander into a rotational force. As compared with the driving source, a rotational force (power) for efficiently driving the generator can be obtained from low-pressure steam. Therefore, by arranging a power generation device using the positive displacement expander in the steam process, low-pressure steam using a small boiler or the like in a small-scale manufacturing factory as a steam source, for example, steam of less than 10 atmospheres is used. It is possible to perform highly efficient power generation even in the case of a steam process.

JP 2007-74894 A

  In the positive displacement expander that obtains power from steam as described above, the energy of the steam is converted into rotational force (power) that drives the generator and used. The energy of has decreased. Therefore, usually, a part of the steam is condensed from the steam that has passed through the positive displacement expander, and drainage is generated. In particular, in the positive displacement expander that can efficiently convert the energy of steam into the motive power to drive the generator, the energy of the steam that has passed through is greatly reduced, and therefore, the generation of drain increases.

  When the drain thus generated is removed by a drain separator or the like, the amount of steam supplied to a process (manufacturing process or the like) on the downstream side of the positive displacement expander decreases. Therefore, in the steam process, when the power generation device is used in a state where there is no surplus steam, it is necessary to add the reduced steam. When steam is newly added to the steam process as described above, fuel or the like is separately required to generate the steam, and the economic efficiency of the steam process is lowered.

  Then, this invention makes it a subject to provide the electric power generating apparatus which can suppress the drain which generate | occur | produces from a vapor | steam in the case of electric power generation.

  Therefore, in order to solve the above problems, a power generation device according to the present invention is a power generation device that generates power using supplied steam and discharges the steam used for power generation, and is configured to supply the steam introduced into the expansion chamber. A positive displacement expander that generates power in response to a change in the volume of the expansion chamber due to pressure, and the positive displacement expander is connected to the positive displacement expander via a power transmission unit so that the power from the positive displacement expander is transmitted. And a drain suppressing means for suppressing the drain generated from the steam when the supplied steam passes through the positive displacement expander.

  According to such a configuration, the positive displacement expander generates power by the steam supplied to the power generation device, and the power is transmitted to the power generator connected to the positive displacement expander, thereby generating the power generation device. Will generate electricity.

  At this time, in the steam, the energy of the steam decreases by passing through the positive displacement expander, in other words, through the expansion process due to the volume change of the expansion chamber. The generation of drain is suppressed. That is, it is possible to generate power while suppressing the generation of drain from the steam.

  In the power generator according to the present invention, the positive displacement expander is preferably a screw expander.

  By adopting such a configuration, it is possible to recover energy from wet steam, corrosive gas, and the like, and the working fluid restriction in the power generation apparatus is reduced. In addition, since the screw expander is a rotary displacement type fluid machine, it has a large handling flow rate even though it is a displacement type, and its output is larger than that of other displacement type expanders. Therefore, it is possible to generate power efficiently while being small.

  Further, the drain suppressing means may be a throttle expansion means that is provided in a flow path on the downstream side of the positive displacement expander so that the passing steam is throttled and expanded. In this case, the throttle expansion means is preferably a pressure reducing valve.

  According to such a configuration, on the downstream side of the positive displacement expander, the pressure required by the process downstream of the positive displacement expander from the downstream pressure (exit pressure) (hereinafter simply referred to as “process side”). Also referred to as “pressure”), it is possible to re-evaporate the drain generated in the steam when the pressure is reduced by the expansion means, thereby suppressing the generation of the drain.

  That is, by providing the throttle expansion means, when the steam passes through the expansion means, the steam is decompressed in a state where the specific enthalpy is constant due to the expansion action of the steam, and the process is started from the outlet pressure of the positive displacement expander. The pressure is reduced to the side pressure. During the decompression, the dryness of the steam is improved, and the state quantity of the steam changes from the wet steam state to the dry steam state. That is, when drain is generated in the steam that has passed through the positive displacement expander, the drain is re-evaporated. Therefore, by providing the throttle expansion means, it becomes possible to adjust the pressure of the steam to the process side pressure while suppressing the generation of drain from the steam that has passed through the positive displacement expander.

  In particular, by configuring the throttle expansion means with the pressure reducing valve whose opening degree can be adjusted, the pressure reducing valve can be operated even when there is a fluctuation in the flow rate of steam supplied to the positive displacement expander or a fluctuation in process side pressure. By adjusting the pressure, the outlet pressure of the positive displacement expander is adjusted, and by passing the steam through the throttle expansion means, it is possible to change the state to superheated steam or saturated steam and to reduce the pressure to the process side pressure.

  Further, in the steam process in which there is almost no fluctuation in the steam flow rate or process side pressure from the upstream side, the throttle expansion means may be a throttle valve or a throttle part formed in the flow path. Thus, even if the throttle expansion means is constituted by the throttle valve or the throttle portion whose opening degree cannot be adjusted, the outlet pressure and the process side pressure of the positive displacement expander are the same as those described above by the throttle valve or the throttle portion. By setting the opening degree of the flow path so that the steam has a pressure ratio that changes state with superheated steam or saturated steam by passing through the throttle valve or the throttle part, generation of drain is prevented. It is possible to suppress and adjust to the process side pressure.

  In addition, the drain suppressing means generates a negative pressure using steam supplied to the nozzle portion, and sucks other steam from the suction portion by this negative pressure, and a flow upstream of the positive displacement expander. A branch flow path branched from the path; and a discharge flow path connected to the downstream side of the positive displacement expander. The ejector is connected to the nozzle section and the suction section. May be configured to be connected to the discharge channel. In this case, it is preferable that the branch flow path is provided with a flow rate adjustment valve.

  In the expansion process when passing through the positive displacement expander, the steam is condensed and drain is generated. This drain is sucked from the suction portion of the ejector via the discharge flow path, and the positive displacement expander. The steam is diverted from the flow path on the upstream side and mixed with the steam that is in the superheated steam state in the nozzle portion of the ejector, and is evaporated again to become steam. As a result, the generation of drain from the steam is suppressed as the entire power generation apparatus.

  Further, the steam in the discharge flow path of the positive displacement expander is pressurized by the ejector and discharged to the process side. That is, the outlet pressure of the positive displacement expander can be made lower than the process side pressure. Therefore, the pressure difference between the inlet pressure and the outlet pressure of the positive displacement expander can be made larger than the pressure difference between the pressure of the steam supplied from the steam source and the process side pressure. Therefore, it becomes possible to collect | recover the energy which the said steam supplied to the said electric power generating apparatus has as work (power) to the maximum, and electric power generation efficiency improves more.

  Further, by providing the flow rate adjustment valve in the branch flow path, the flow rate of the steam supplied to the nozzle portion can be adjusted, and the pressure of the steam in the discharge flow path (of the positive displacement expander) It is easy to adjust the pressure difference between the outlet pressure) and the pressure of the steam on the downstream side of the ejector (process side pressure).

  Further, the drain suppressing means is constituted by a compressor provided in a flow path on the downstream side of the positive displacement expander, and the compressor may be connected to the power transmission means and driven. Good.

  According to such a configuration, the steam is condensed in the expansion process when passing through the positive displacement expander, and drain is generated at one end. This drain is contained in the compressor together with the steam discharged from the positive displacement expander. And is re-evaporated into steam by being compressed in the compressor. As a result, the generation of drain from the steam is suppressed as the entire power generation apparatus.

  Further, since the pressure of the steam discharged from the positive displacement expander can be increased by the compressor, the outlet pressure of the positive displacement expander can be made lower than the process side pressure. That is, as described above, the pressure difference between the inlet pressure and the outlet pressure of the positive displacement expander can be made larger than the pressure difference between the pressure of the steam supplied from the steam source and the process side pressure. Therefore, it becomes possible to collect | recover the energy which the said steam supplied to the said electric power generating apparatus has as work (power) to the maximum, and electric power generation efficiency improves more.

  In this case, the power transmission means may be constituted by a rotary drive shaft that connects the positive displacement expander and the generator, and the compressor may be connected to the rotary drive shaft.

  According to this configuration, since the positive displacement expander and the generator are connected via the rotary drive shaft, the mechanical loss of the power is greater than when the power is transmitted via a plurality of members. Can be reduced. Therefore, the power generation efficiency is further improved.

  Further, by adopting a simple configuration such as the rotary drive shaft, the power transmission means is unlikely to fail and maintenance is facilitated.

  The power transmission means is constituted by a plurality of gears, and the compressor has a gear for obtaining power from the outside, and the gear is arranged so as to mesh with any of the plurality of gears. It may be.

  According to such a configuration, it is possible to easily obtain a desired outlet pressure (process side pressure) of the compressor and a desired outlet pressure of the positive displacement expander by setting the gear ratio of each gear. Therefore, the pressure difference between the inlet pressure and the outlet pressure of the positive displacement expander can be set to a desired pressure difference, and the process side pressure can also be set to a desired pressure.

  Moreover, even if a certain amount of liquid is introduced in the said compressor, it becomes difficult to break down because the said compressor is comprised with a screw compressor. Therefore, the flow path between the positive displacement expander and the screw compressor may be provided with a drain diffuser for scattering the vapor condensed when passing through the positive displacement expander. In the flow path between the positive displacement expander and the screw compressor, a liquid injection device for injecting the liquid constituting the vapor into the flow path may be provided.

  By providing such a drain scattering device, even if the drain that is generated once the vapor is condensed during the expansion process in the positive displacement expander becomes a liquid film in the flow path, the liquid film is in the flow. The drain re-evaporation in the compressor is facilitated by being scattered in the steam in the passage. As a result, the generation of drain is further suppressed.

  In addition, the amount of vapor supplied to the process side can be increased by injecting the liquid by the liquid injection device.

  As mentioned above, according to this invention, the electric power generating apparatus which can suppress the drain generate | occur | produced from a vapor | steam in the case of electric power generation can be provided.

It is a schematic block diagram of the whole steam process which concerns on 1st Embodiment. It is a schematic block diagram in the electric power generating apparatus which concerns on the same embodiment. (A) in the screw expander which concerns on the same embodiment is a fragmentary sectional top view, (b) is a fragmentary sectional side view, (c) is AA sectional drawing in Fig.3 (a). (A) And (b) in the screw expander which concerns on the embodiment is a perspective view of a pair of screw rotor for showing the volume change of an expansion chamber. (A) in the electric power generating apparatus which concerns on the embodiment is a figure which shows the state change of a vapor | steam, (b) is a figure which shows the state change of a vapor | steam when changing the exit pressure of a screw expander. It is a schematic block diagram of the part corresponded to the part enclosed with the dotted line of FIG. 2 in the electric power generating apparatus which concerns on 2nd Embodiment. It is a longitudinal cross-sectional view of the ejector which concerns on the same embodiment. It is a figure which shows the theoretical electric power generation when the outlet pressure of the screw expander which concerns on the embodiment is represented by the pressure difference from inlet pressure. It is a schematic block diagram of the part corresponded to the part enclosed with the dotted line of FIG. 2 in the electric power generating apparatus which concerns on 3rd Embodiment. It is a figure which shows the modification of 3rd Embodiment shown by FIG. 9, Comprising: (a) is a schematic block diagram which shows the state which has arrange | positioned the screw expander and the screw compressor on both sides of a generator, (b) FIG. 2 is a schematic configuration diagram showing a state in which a drain separator and a liquid injection device are provided in a connecting pipe, and FIG. 3C is a schematic configuration diagram showing a state in which a drain scattering device and a liquid injection device are provided in the connection pipe. It is a figure which shows the modification of 3rd Embodiment shown by FIG. 9, Comprising: It is a schematic block diagram which shows the state in which the power transmission means was comprised with several gears.

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 and 2.

  The power generation apparatus 20 according to the present embodiment uses steam energy generated by a steam source (steam generating means) 10 such as a boiler and used in steam utilization equipment (hereinafter also simply referred to as “process”) 12. It is a device that generates electricity.

  The steam source 10 and the process 12 are connected by a main pipe 14 through which steam flows. The main pipe 14 is provided with a control valve 16.

  Process 12 is equipment using steam, such as a water heater, a heater, a dryer, a washing equipment, and a sterilizer. The control valve 16 functions as a pressure reducing valve when the power generation device 20 does not generate power, and closes the main pipe 14 when the power generation device 20 generates power.

  When the pressure of the steam supplied from the steam source 10 is reduced to a pressure required by the downstream process 12 (hereinafter, also simply referred to as “process side pressure”), the power generation apparatus 20 It is a device that generates power using the pressure difference. Specifically, a positive displacement expander 22, a generator 24, a frequency converter 26, a controller 28, and the like are provided, and these are accommodated in a casing 30.

  The positive displacement expander 22 is an expander that generates power in accordance with the volume change of the expansion chamber due to the pressure of the steam (fluid) introduced into the expansion chamber formed inside. In the present embodiment, a screw expander (so-called screw expander) 22 is used, and the screw expander 22 is a rotary displacement type fluid machine.

  Specifically, as shown in FIGS. 3A to 4B, the screw expander 22 is rotatable in the expander casing 34 in which the rotor chamber 32 is formed and the rotor chamber 32. And a pair of male and female screw rotors 36 and 38 to be arranged. These female and male screw rotors 36, 38 are provided with spiral blades 36a, 38a in opposite directions. Moreover, it arrange | positions in the rotor chamber 32 of the expander casing 34 so that the rotating shafts 36b and 38b may become mutually parallel. The expansion chamber 40 is formed by being surrounded by the blades 36a and 38a of the rotors 36 and 38 and the expander casing 34 (see the hatched portions in FIGS. 4A and 4B). As will be described later, when steam is introduced into the expansion chamber 40 and expands, the volume of the expansion chamber 40 increases and the screw rotors 36 and 38 rotate. In the expander casing 34, an inlet (air supply port) 42 to which steam is supplied is formed at one end in the axial direction of the screw rotor 36 (or 38), and steam that has undergone an expansion process is formed at the other end. A discharge outlet (exhaust port) 44 is formed.

  A supply pipe 46 is connected to the inlet 42 of the screw expander 22, and a discharge pipe 48 is connected to the outlet 44. The supply pipe 46 is connected to the upstream side of the control valve 16 in the main pipe 14, and the discharge pipe 48 is connected to the downstream side of the control valve 16 in the main pipe 14. Thereby, the steam generated by the steam source 10 is supplied to the screw expander 22, and the steam discharged from the screw expander 22 is returned to the main pipe 14.

  The supply pipe 46 is provided with a supply steam gate valve (open / close valve) 50, a drain separator 52, and an emergency shut-off valve 54 in order from the upstream side. The supply steam gate valve 50 is provided near the outside of the casing 30 in the supply pipe 46. The drain separator 52 is for separating drain from the steam flowing through the supply pipe 46. The emergency shut-off valve 54 completely closes the supply pipe 46 and can be opened and closed by the controller 28.

  A discharge steam gate valve (open / close valve) 56 is provided near the outside of the casing 30 in the discharge pipe 48. The exhaust steam gate valve 56 and the supply steam gate valve 50 of the supply pipe 46 constitute switching means for switching whether or not the steam flowing through the main pipe 14 is introduced (supplied) to the supply pipe 46. That is, when the steam generated in the steam source 10 is supplied to the process 12 as it is, both the steam gate valves 50 and 56 are closed and the control valve 16 is opened. The valves 50 and 56 are opened and the control valve 16 is closed. Both of these steam gate valves 50 and 56 may be configured by either a gate valve that can be switched to a fully open state or a fully closed state, or a gate valve that can be adjusted in opening. Further, as the switching means, a three-way switching valve may be provided instead of the steam gate valve. In this case, the three-way switching valve is disposed at a connection portion between the main pipe 14 and the supply pipe 46 and a connection portion between the main pipe 14 and the discharge pipe 48. In this case, the control valve 16 may be changed to a pressure reducing valve that simply reduces the pressure of the passing steam.

  Further, a drain suppression pressure reducing valve 58 is provided between the outlet 44 of the screw expander 22 and the discharge steam gate valve 56 in the discharge pipe 48. The drain suppression pressure reducing valve 58 is a pressure reducing valve that is squeezed and expanded when the steam flowing through the discharge pipe 48 passes through the drain suppression pressure reducing valve 58. In this embodiment, the drain suppression pressure reducing valve 58 passes through the screw expander 22 as described later. The drain suppressing means for suppressing the drain generated from the generated steam is configured.

  Further, in the discharge pipe 48, a first pressure gauge 60 is provided between the outlet 44 of the screw expander 22 and the drain suppression pressure reducing valve 58, and a second pressure gauge 60 is provided between the drain suppression pressure reducing valve 58 and the discharge steam gate valve 56. A pressure gauge 62 is provided. The first pressure gauge 60 is a pressure gauge that measures the pressure of steam flowing in the discharge pipe 48 from the outlet 44 of the screw expander 22 to the drain suppression pressure reducing valve 58, and the second pressure gauge 62 is a drain suppression pressure reducing valve. It is a pressure gauge that measures the pressure of steam flowing in the discharge pipe 48 from 58 to the discharge steam gate valve 56.

  Each pressure data in the discharge pipe 48 measured by the first and second pressure gauges 60 and 62 is sent to the controller 28, and the controller 28 controls the rotational speed of the generator 24 based on the pressure data as will be described later. And / or the drain suppression pressure reducing valve 58 is controlled (opening adjustment).

  The generator 24 is connected to the screw expander 22 via a power transmission means 64. Specifically, the rotating shaft of the generator 24 is connected to the rotating shaft 36b (or 38b) of the screw expander 22 via the rotation drive shaft 64. Therefore, when the energy of the steam supplied to the screw expander 22 is converted into rotational power, this rotational power is transmitted to the rotational shaft of the generator 24 via the rotational drive shaft 64, and power is generated in the generator 24.

  The electricity generated by the generator 24 is sent to the frequency converter 26. The frequency converter 26 converts the frequency of electricity generated by the generator 24, and converts, for example, electricity of 30 to 120 Hz into electricity having a commercial frequency of AC 50 or 60 Hz.

  The controller 28 controls the rotational speed of the generator 24 based on the pressure data measured by the first pressure gauge 60, controls the drain suppression pressure reducing valve 58 based on the pressure data measured by the second pressure gauge 62, and opens / closes the emergency shut-off valve 54. The operation control of each element constituting the power generation device 20 is performed.

  The power generator 20 according to the first embodiment has the above-described configuration. Next, the operation of the power generator 20 will be described.

  The steam generated by driving the steam source 10 such as a boiler flows through the main pipe 14, is decompressed by the control valve 16, and is then supplied to the downstream process 12. When power generation is performed, the supply steam gate valve 50 of the supply pipe 46 and the discharge steam gate valve 56 of the discharge pipe 48 are opened and the control valve 16 is closed, whereby the main pipe 14 is generated by the steam source 10. The steam that has flowed through is supplied to the supply pipe 46.

  The steam supplied from the main pipe 14 to the supply pipe 46 is introduced into the inside through an inlet (air supply port) 42 of the screw expander 22. The introduced steam tends to push the wall of the expansion chamber 40 composed of the pair of male and female screw rotors 36 and 38 and the expander casing 34 evenly (see FIG. 4A). The expander casing 34 is fixed, and the back side (exit 44 side) of the blades 36a and 38a of a pair of male and female screw rotors 36 and 38, which are rotating bodies, has a lower pressure than the front side (inlet 42 side). Therefore, both screw rotors 36 and 38 rotate by the pressure difference between the front side and the back side of the blades 36a and 38a (see arrows in FIG. 4A). As both screw rotors 36 and 38 rotate, the confining volume of the expansion chamber 40 increases (see the shaded area in FIGS. 4A and 4B), and the steam also expands at the same time. When the maximum is reached, the outlet (exhaust port) 44 of the screw expander 22 is reached, and the confinement in the expansion chamber 40 is released and discharged. As this operation continues, rotational power is generated and transmitted to the generator 24 via the rotational drive shaft 64 to rotate the rotational shaft of the generator 24.

  The generator 24 generates electric power by rotating its rotating shaft by the rotational power transmitted from the screw expander 22. The electricity generated by the generator 24 is sent to the frequency converter 26. The frequency converter 26 converts the current into a commercial frequency current as described above, and sends the current to the system 68 via the transformer 66.

  On the other hand, the steam discharged from the screw expander 22 flows through the discharge pipe 48 and passes through the drain suppression pressure reducing valve 58. At this time, the steam is squeezed and expanded to be reduced to the process side pressure, then flows through the discharge pipe 48, is returned to the main pipe 14, and is supplied to the downstream process 12.

  In the pressure reduction by the drain suppression pressure reducing valve 58, the drain suppression pressure reducing valve 58 is controlled based on the measurement by the second pressure gauge 62 in order to set the pressure in the discharge pipe 48 to the process side pressure. Specifically, the pressure data measured by the second pressure gauge 62 is sent to the controller 28, and the opening degree of the drain suppression pressure reducing valve 58 is adjusted by a command from the controller 28 based on this pressure data. The pressure of the steam after passing through 58 is reduced to a process side pressure.

  At this time, the pressure on the upstream side of the drain suppression pressure reducing valve 58, that is, the pressure at the outlet 44 of the screw expander 22 (outlet pressure) becomes higher than the process side pressure by providing the drain suppression pressure reducing valve 58. Yes. When the amount of steam supplied to the screw expander 22 (steam flow rate) fluctuates, the number of steam discharged by controlling the number of revolutions of the screw expander 22 is controlled. The outlet pressure is kept constant.

  The rotational speed control of the screw expander 22 is performed by controlling the rotational speed of the generator 24 based on the measurement by the first pressure gauge 60. That is, since the rotating shaft of the generator 24 and the rotating shaft 36b (or 38b) of the screw expander 22 are connected by the rotation drive shaft 64, the rotation speed of the generator 24 is controlled to control the screw expander 22's rotation speed. The rotation speed is controlled.

  Specifically, the fluctuation of the outlet pressure of the screw expander 22 due to the fluctuation of the steam amount is measured by the first pressure gauge 60, and the pressure data is sent to the controller 28. The controller 28 calculates the rotation speed at which the outlet pressure of the screw expander 22 becomes a desired pressure based on this pressure data. Further, the number of rotations of the generator 24 is calculated so that the number of rotations of the screw expander 22 is the calculated number of rotations, and a command is sent to the generator 24 so that the number of rotations is the same. By controlling in this way, even if the amount of steam supplied to the screw expander 22 varies, the outlet pressure of the screw expander 22 is set to a desired pressure (constant pressure). Rotational speed control is performed.

  The desired outlet pressure in the screw expander 22 is derived as follows. Here, the inlet pressure of the screw expander 22 is P1, the pressure in the expansion chamber 40 immediately before opening the expansion chamber 40 in the screw expander 22 is P2, the process side pressure is P3, the outlet pressure of the screw expander 22 (the above-mentioned The desired outlet pressure is P4. The case where the steam required in the process 12 is saturated steam will be described.

  The steam supplied to the screw expander 22 passes through the screw expander 22 and is decompressed from P1 to P2 through an expansion process. The change in the state quantity of the steam at this time changes as indicated by an arrow QS1 shown in FIG. The steam that has undergone this expansion process is boosted from P2 to P4 when the expansion chamber 40 of the screw expander 22 is opened. The change in the state quantity at this time changes as indicated by an arrow QS2 shown in FIG. Then, the steam whose pressure becomes P4 is reduced in pressure from P4 to P3 by passing through the drain suppression pressure reducing valve 58 and being expanded by expansion. At this time, the pressure of the steam decreases with a constant specific enthalpy as indicated by an arrow QS3 shown in FIG. Thus, when the steam pressure is reduced to P3, the pressure of P4 is set so that the intersection of the state quantity change arrow QS3 and the pressure P3 is located on the saturated steam line.

  When the steam required in the process 12 is dry steam, the arrow QS3 shown in FIG. 5A intersects with the saturated steam line before reaching P3, that is, as shown in FIG. 5B. Thus, the value of P4 should just be set so that the intersection of arrow QS3 and pressure P3 may be located in the area | region (dry steam side) above a saturated vapor line.

  As described above, according to the present embodiment, by providing the drain suppression pressure reducing valve 58 (throttle expansion means), when the steam passes through the drain suppression pressure reducing valve 58, the specific enthalpy is constant due to the expansion expansion action. In this state, the steam is decompressed and decompressed from the outlet pressure P4 of the screw expander 22 to the process side pressure P3. During this decompression, the dryness of the steam is improved and the state quantity of the steam changes from the wet steam state to the dry steam state. That is, when drain is generated in the steam that has passed through the screw expander 22, the drain is re-evaporated. Therefore, by providing the drain suppression pressure reducing valve 58, it becomes possible to adjust (depressurize) the pressure P4 of the steam to the process side pressure P3 while suppressing the generation of drain from the steam that has passed through the screw expander 22.

  Further, the throttle expansion means is constituted by a drain suppression pressure reducing valve 58 whose opening degree can be adjusted, so that even when there is a change in the amount of steam supplied to the screw expander 22 or a change in the process side pressure P3, the drain suppression pressure reduction. By controlling the valve 58, the outlet pressure of the screw expander 22 is adjusted, and the state of steam is changed to superheated steam or saturated steam by passing through the drain suppression pressure reducing valve 58, and the pressure is reduced to the process side pressure P3. It becomes possible.

  In the present embodiment, the drain suppression pressure reducing valve 58 is used as the drain suppression means. However, when there is almost no variation in the amount of steam from the steam source 10 or variation in the process side pressure P3, the throttle expansion is performed. The means may comprise a throttle valve or a throttle formed in the discharge pipe 48.

  Thus, even if the throttle expansion means is constituted by the throttle valve or the throttle portion whose opening degree cannot be adjusted, the outlet pressure P4 and the process side pressure P3 of the screw expander 22 are reduced by the throttle valve or the throttle portion. Similarly, by setting the opening degree (throttle degree) of the exhaust pipe 48 so that the pressure ratio is such that the steam changes state with superheated steam or saturated steam when passing through the throttle valve or the throttle part. In addition, the generation of drain can be suppressed and the adjustment to the process side pressure P3 becomes possible.

  Next, a second embodiment of the present invention will be described with reference to FIG. 6 as well. However, the same reference numerals are used for the same components as those in the first embodiment, and a detailed description is omitted, and only different components are described in detail. explain. FIG. 6 is a schematic configuration diagram showing a portion corresponding to the portion surrounded by the dotted line in FIG.

  In the power generation device 20 according to the present embodiment, the drain suppression means is configured by an ejector 70, a branch pipe 72, and a suction discharge pipe 74. As shown in FIG. 7, the ejector 70 includes a nozzle portion 76 that squeezes and expands the supplied fluid (steam) to generate a negative pressure, and a suction unit that sucks another fluid (steam) by the negative pressure. 78 and a diffuser portion 80 that discharges the fluid from the nozzle portion 76 and the suction portion 78 and mixes the fluid from the nozzle portion 76 and the suction portion 78 is provided in the ejector body 81.

  A branch pipe 72 branched from the supply pipe 46 on the upstream side of the screw expander 22 is connected to the nozzle portion 76 of the ejector 70. In the middle of the branch pipe 72, a flow rate adjusting valve 82 for adjusting the amount of steam flowing through the branch pipe 72 is provided. A suction discharge pipe 74 is connected to the suction portion 78 of the ejector 70, and the other end of the suction discharge pipe 74 is connected to the outlet 44 of the screw expander 22. A discharge pipe 48 is connected to the diffuser unit 80.

  The suction discharge pipe 74 is provided with a third pressure gauge 84, and the discharge pipe 48 is provided with a fourth pressure gauge 86. The pressure data measured by the third and fourth pressure gauges is sent to the controller 28.

  Next, operation | movement of this electric power generating apparatus 20 is demonstrated. The steam supplied from the steam source 10 is supplied from the main pipe 14 to the supply pipe 46 and is supplied to the inside from the inlet 42 of the screw expander 22. As in the first embodiment, power is obtained by changing the volume of the expansion chamber 40 in the screw expander 22, and this power is transmitted to the generator 24 to generate power. The electricity generated by this power generation is also converted to a commercial frequency by the frequency converter 26 as in the first embodiment, transformed by the transformer 66, and sent to the system 68. Further, the steam used for power generation is discharged from the screw expander 22, flows through the suction discharge pipe 74, and is sucked into the ejector 70.

  On the other hand, a part of the steam supplied to the supply pipe 46 is diverted to the branch pipe 72 on the upstream side of the screw expander 22 and supplied to the nozzle portion 76 of the ejector 70. The pressure of the steam supplied to the nozzle portion 76 becomes equal to the inlet pressure P1 of the screw expander 22. The steam ejected from the nozzle portion 76 into the ejector main body 81 is squeezed and expanded by the nozzle portion 76 to be in a superheated steam state. Thus, a negative pressure is generated in the ejector main body 81 by the steam ejected from the nozzle portion 76, and the steam in the suction discharge pipe 74 connected to the suction portion 78 is sucked by this negative pressure. The jetted steam and the sucked steam are mixed and discharged from the diffuser portion 80 to the discharge pipe 48.

  At this time, the controller 28 suctions the ejector 70 from the pressure data measured by the third pressure gauge provided in the suction discharge pipe 74 and the pressure data measured by the fourth pressure gauge 86 provided in the discharge pipe 48. The pressure difference between the pressure in the section 78 (the outlet pressure of the screw expander 22) P2 and the pressure in the diffuser section 80 (the pressure in the discharge pipe 48) is calculated. The flow rate adjustment valve 82 is controlled by the controller 28 so that the pressure difference becomes an appropriate pressure difference.

  Specifically, for example, using the ejector 70 described above, the amount of steam supplied to the screw expander 22 is 3.0 t / h, the inlet pressure P1 of the screw expander 22 is 0.7 MPa, and the process side pressure P3 is 0. When the pressure is 2 MPa, the pressure P2 in the suction discharge pipe 74 is controlled to be 0.1 MPa. At this time, the amount of steam passing through the nozzle portion 76 is about 1.2 t / h.

  The steam discharged from the ejector 70 to the discharge pipe 48 returns to the main pipe 14 and is supplied to the downstream process 12.

  As described above, according to the present embodiment, steam is condensed in the expansion process when passing through the screw expander 22 to generate one end of the drain. This drain passes through the suction discharge pipe 74 and is ejected by the ejector 70. Is sucked from the suction part 78 and supplied from the branch pipe 72 and mixed with the steam in the superheated steam state in the nozzle part 76 to re-evaporate to become steam. As a result, the generation of drain from the steam is suppressed as the entire power generation apparatus 20.

  The vapor in the suction discharge pipe 74 on the downstream side of the screw expander 22 is pressurized by the ejector 70 and discharged to the process 12 side (discharge pipe 48). That is, the outlet pressure P2 of the screw expander 22 can be made lower than the process side pressure P3. Therefore, the pressure difference between the inlet pressure P1 and the outlet pressure P2 of the screw expander 22 can be made larger than the pressure difference between the steam pressure P1 supplied from the steam source 10 and the process side pressure P3. Therefore, in the power generation device 20, it is possible to recover the energy of the steam supplied to the power generation device 20 as a maximum work (power), and the power generation efficiency is further improved.

  Specifically, when the ejector 70 is used as the drain suppressing means, it can be seen from FIG. 8 that, for example, the power generation output increases by about 50% when the pressure difference is changed from 0.5 MPa to 0.6 MPa. Here, FIG. 8 shows that the above-described ejector 70 is used in the power generation apparatus 20 according to this embodiment, the amount of steam supplied to the screw expander 22 is 3.0 t / h, and the pressure of the steam in the screw expander 22 When the conversion efficiency of the screw expander 22 when the pressure is reduced from P1 to P2 is 70%, the inlet pressure P1 of the screw expander 22 is 0.7 Pa, and the process side pressure P3 is 0.2 MPa, the screw expander The power generation amount when 22 outlet pressures P2 are expressed by a pressure difference from the inlet pressure P1 is shown.

  By providing the flow adjustment valve 82 in the branch pipe 72 as in the present embodiment, the amount of steam supplied to the nozzle portion 76 can be adjusted, and the pressure in the suction discharge pipe 74 (the outlet pressure of the screw expander 22) can be adjusted. ) It is easy to adjust the pressure difference between P2 and the pressure (process side pressure) P3 on the downstream side of the ejector 70.

  However, when the amount of steam supplied from the steam source 10 is constant and the process side pressure does not fluctuate, the pressure difference between the P2 and P3 is constant, so the branch pipe 72 does not have the flow control valve 82. Also good.

  Next, a third embodiment of the present invention will be described with reference to FIG. 9 as well. The same reference numerals are used for the same components as those in the first and second embodiments, and a detailed description thereof is omitted. Only the details will be described. 9 is also a schematic configuration diagram showing a portion corresponding to the portion surrounded by the dotted line in FIG.

  In the power generation apparatus 20 according to the present embodiment, the drain suppression unit is configured by the compressor 90. The compressor 90 is a screw compressor having a configuration similar to that of a screw expander, in which the rotation direction of a pair of male and female screw rotors 36 and 38 is reverse.

  The screw compressor 90 is provided on the downstream side of the screw expander 22, and the outlet 44 of the screw expander 22 and the inlet of the screw compressor 90 are connected by a connecting pipe 92. The outlet of the screw compressor 90 is connected to the discharge pipe 48. By being connected in this way, the steam discharged from the screw expander 22 is compressed by the screw compressor 90 and pressurized, and then discharged to the discharge pipe 48.

  The screw compressor 90 is coupled to a rotary drive shaft 64 that transmits power from the screw expander 22 to the generator 24. Specifically, the rotation shaft 36b (or 38b) of one screw rotor 36 (or 38) of the screw compressor 90 and the rotation drive shaft 64 are configured by a common shaft, and the screw compressor 90 is configured by the screw expander 22. And the generator 24.

  The discharge pipe 48 on the downstream side of the screw compressor 90 is provided with a fifth pressure gauge 94, and pressure data measured by the pressure gauge 94 is sent to the controller 28.

  Next, operation | movement of this electric power generating apparatus 20 is demonstrated. The steam supplied from the steam source 10 is supplied from the main pipe 14 to the supply pipe 46 and is supplied to the inside from the inlet 42 of the screw expander 22. As in the first embodiment, power is obtained by changing the volume of the expansion chamber 40 in the screw expander 22, and this power is transmitted to the generator 24 to generate power. The electricity generated by this power generation is also converted to a commercial frequency by the frequency converter 26 as in the first embodiment, transformed by the transformer 66, and sent to the system 68. The steam used for power generation is reduced in pressure from the steam pressure P1 supplied from the steam source 10 to the outlet pressure P2 of the screw expander 22 by converting the energy of the steam into rotational power in the expansion process. And is discharged from the screw expander 22. The discharged steam flows through the connecting pipe 92 and is supplied to the screw compressor 90.

  In the screw compressor 90, the steam supplied from the screw expander 22 is compressed by the connecting pipe 92, and the pressure is increased from the outlet pressure P2 of the screw expander 22 to the process side pressure P3. At this time, the screw compressor 90 obtains a driving force from the rotary drive shaft 64 and performs the compression.

  The compressed steam is discharged from the screw compressor 90 to the discharge pipe 48. The pressure of the discharged steam is measured by the fifth pressure gauge 94, and the controller 28 controls the rotational speed of the generator 24 based on the pressure data obtained by this measurement, so that the process side pressure P3 is set to a desired pressure. adjust.

  Specifically, since the screw expander 22 and the screw compressor 90 are connected by the rotation drive shaft 64, the rotation speed is the same. The generator 24 is also connected to the rotary drive shaft 64. Therefore, the rotational speed control of the screw expander 22 and the screw compressor 90 can be performed simultaneously by controlling the rotational speed of the generator 24. At this time, the ratio of the inlet pressure P1 and the outlet pressure P2 of the screw expander 22 and the ratio of the inlet pressure P2 and the outlet pressure P3 of the screw compressor 90 are both designed values (designed expansion ratio and designed compression ratio). It is the same.

  The steam discharged from the screw compressor 90 to the discharge pipe 48 returns to the main pipe 14 and is supplied to the downstream process 12.

  As described above, according to the present embodiment, the steam is condensed in the expansion process when passing through the screw expander 22 to generate one end of the drain. This drain is the steam discharged from the screw expander 22. At the same time, it is introduced into the screw compressor 90 and compressed in the screw compressor 90 to re-evaporate into steam. As a result, the generation of drain from the steam is suppressed as the entire power generation apparatus 20.

  Moreover, since the pressure of the vapor | steam discharged | emitted from the screw expander 22 by the screw compressor 90 can be raised, the exit pressure P2 of the screw expander 22 can be made lower than the process side pressure P3. That is, as in the second embodiment, the pressure difference between the inlet pressure P1 and the outlet pressure P2 of the screw expander 22 is made larger than the pressure difference between the steam pressure P1 supplied from the steam source 10 and the process side pressure P3. Is possible. Therefore, it is possible to recover the energy of the steam supplied to the power generation device 20 as a maximum work (power), and the power generation efficiency is further improved.

  In the present embodiment, the screw expander 22, the generator 24, and the screw compressor 90 are connected by a common rotary drive shaft 64. Therefore, compared with the case where the power from the screw expander 22 is transmitted to the generator 24 and the screw compressor 90 via a plurality of members, the mechanical loss of the power can be reduced, and the power generation efficiency is further improved. . Further, by adopting a simple configuration such as the rotary drive shaft 64 as means for transmitting the power, it is difficult for the power transmission means to fail and maintenance is facilitated.

  In addition, the electric power generating apparatus of this invention is not limited to the said embodiment, Of course, a various change can be added in the range which does not deviate from the summary of this invention.

  For example, in the third embodiment, the screw expander 22, the screw compressor 90, and the generator 24 are sequentially arranged along the rotation drive shaft 64, but the present invention is not limited to this, and FIG. As shown in a), the screw expander 22, the generator 24, and the screw compressor 90 may be arranged in this order along the rotational drive shaft 64. Even if they are arranged in this order, each of them is connected by a common rotational drive shaft 64, so that it is possible to control the other two rotational speeds simultaneously by controlling any one rotational speed. It becomes. Therefore, the order may be changed as necessary depending on the space in the casing 30 or the like.

  In the third embodiment, a drain scattering device 96 may be provided in the connecting pipe 92 (see FIG. 10C). This drain scattering device 96 is for scattering the drain condensed steam in the expansion process and dispersing it again in the steam. By providing such a drain scattering device 96 in the connecting pipe 92, even if the drain once generated by the condensation of steam in the expansion process in the screw expander 22 becomes a liquid film in the connecting pipe 92, this liquid The membrane is scattered in the steam in the connecting pipe 92, so that the drain can be easily re-evaporated in the screw compressor 90.

  In the third embodiment, as shown in FIG. 10B, a liquid injection device 98 may be provided in the connecting pipe 92. The liquid injection device 98 is for injecting a liquid constituting the vapor into the connecting pipe 92. Such a liquid injection device 98 is provided in the connecting pipe 92, and the liquid is injected into the connecting pipe 92, whereby the amount of vapor supplied to the process 12 can be increased. In this case, by providing the drain separator 100 in the connection pipe 92, the liquid may be injected by the liquid injection device 98 after the drain is separated and discharged from the vapor in the connection pipe 92. Further, by providing only the drain separator 100 in the connecting pipe 92 without providing the liquid injection device 98, superheated steam can be obtained in the process 12.

  In addition, since the compressor is composed of a positive displacement compressor (screw compressor 90 in the third embodiment), even if liquid from the liquid injection device 98 or the like is introduced into the compressor, it is difficult to break down. Become.

  The drain scattering device 96 and the liquid injection device 98 may be provided in the connection pipe 92 as shown in FIG. By providing both in the connecting pipe 92 in this way, the drain that has become a liquid film in the connecting pipe 92 can be easily re-evaporated by the screw compressor 90, and the amount of steam supplied to the process 12 can be increased. it can.

  In the third embodiment, the rotational drive shaft 64 is used as power transmission means for transmitting the power (rotational power) generated by the screw expander 22 to the generator 24 and the screw compressor 90, but the present invention is not limited to this. It is not necessary to be made, and as shown in FIG. 11, it may be constituted by a plurality of gears 102, 102,. In this case, the compressor 90 has a gear 104 for obtaining power from the outside, and the gear 104 may be disposed so as to mesh with any of the plurality of gears 102, 102,. In FIG. 11, the plurality of gears 102, 102,... And the gear 104 included in the screw compressor 90 constitute a speed reducer 106.

  By configuring the power transmission means as described above, setting the gear ratio of the gears 102 and 104 allows the desired outlet pressure (process side pressure) P3 of the screw compressor 90 and the desired screw expander 22 to be set. It is possible to easily obtain the outlet pressure P2. Therefore, the pressure difference between the inlet pressure P1 and the outlet pressure P2 of the screw expander 22 can be set to a desired pressure difference, and the process side pressure P3 can also be set to a desired pressure.

  Furthermore, the freedom degree of arrangement | positioning of the screw expander 22, the generator 24, and the screw compressor 90 improves by the combination of various gears. Moreover, it is good also as a mechanism (transmission mechanism etc.) which can change the combination of a gearwheel. In this case, the pressures P1, P2, and P3 at each part are appropriate pressures (design expansion ratio and screw compressor in the screw expander 22) in accordance with fluctuations in the amount of steam supplied from the steam source 10 and process side pressure. The controller 28 performs control such that the combination of gears is changed so that the rotation speeds of the screw expander 22, the generator 24, and the screw compressor 90 become appropriate rotation speeds so that the design compression ratio at 90 can be obtained. Is called.

DESCRIPTION OF SYMBOLS 10 Steam source 12 Process 14 Main piping 16 Control valve 20 Electric power generation device 22 Screw expander (volume type expander)
24 Generator 40 Expansion chamber 58 Drain suppression pressure reducing valve (Drain suppression means)
64 Rotation drive shaft (power transmission means)
70 Ejector 72 Branch pipe (Branch channel)
74 Suction discharge pipe 76 Nozzle part 78 Suction part 82 Flow rate adjusting valve 90 Screw compressor (compressor)
96 Drain scattering device 98 Liquid injection device 102 Gear 104 Gear

Claims (3)

A power generation device that generates electric power with supplied steam and discharges the steam used for power generation,
A positive displacement expander that generates power in response to a change in volume of the expansion chamber due to the pressure of the steam introduced into the expansion chamber;
A generator coupled to the positive displacement expander via power transmission means so that the power from the positive displacement expander is transmitted;
A drain suppression means for suppressing drainage generated from the steam when the supplied steam passes through the positive displacement expander;
The drain suppressing means generates a negative pressure using steam supplied to the nozzle portion, and sucks other steam from the suction portion by this negative pressure, and a flow path upstream of the positive displacement expander. A branched flow path branched and a discharge flow path connected to the downstream side of the positive displacement expander,
The power generator according to claim 1, wherein the ejector is connected to the branch passage in the nozzle portion and to the discharge passage in the suction portion.   The power generation device according to claim 1, wherein a flow rate adjusting valve is provided in the branch flow path. Positive displacement expander, power generator according to claim 1 or 2, characterized in that a screw expander.

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