JP4982985B2 - Steam generation system - Google Patents

Description

  The present invention relates to a steam generation system.

As a steam generation system, generally known is a configuration in which a heated medium is heated by burning fuel in a boiler (see, for example, Patent Document 1).
JP-A-6-249450

  The energy efficiency of the boiler is generally about 0.8 (80%). With increasing awareness of environmental issues, further improvements in energy efficiency are desired for steam generation systems.

  This invention is made | formed in view of the situation mentioned above, and is providing the steam generation system with high energy efficiency.

  The steam generation system of the present invention includes a supply path for a heated medium, a heat pump for heating the heated medium in the supply path, and the heated medium disposed on the supply path and heated by the heat pump. And a compressor for compression.

  According to this steam generation system, energy efficiency improves compared with a boiler by utilizing a heat pump. The energy efficiency of the boiler is generally about 0.8 (about 80%), and the coefficient of performance (COP) as the energy efficiency of the heat pump is generally 2.5 to 5.0. The heated medium heated by the heat pump is further heated by compression by the compressor. Since the compressor compensates for a part of the heating temperature region for generating steam, a heat pump is used at a high COP.

  In the steam generation system of the present invention, the medium to be heated in the supply path becomes steam having a relatively low pressure and low temperature by heating by the heat pump, and steam having a relatively high pressure and high temperature by compression by the compressor. It can be configured.

  In the steam generation system of the present invention, the internal pressure at the heating position by the heat pump in the supply path can be lower than the atmospheric pressure.

  In the steam generation system of the present invention, the medium to be heated in the supply path becomes saturated steam at a negative pressure lower than the atmospheric pressure by heating with the heat pump, and the atmospheric pressure or the atmospheric pressure is increased by compression by the compressor. It can be configured to become steam at a pressure higher than atmospheric pressure.

  Moreover, the steam generation system of this invention WHEREIN: The internal space in the heating position by the said heat pump in the said supply path | route can be comprised by the said compressor.

  In the steam generation system of the present invention, the supply path may have a tank that stores the liquid medium to be heated.

  In this case, the gas phase in the tank is sucked into the compressor, and the liquid phase in the tank is heated by the heat pump inside or outside the tank.

  In this case, the supply amount of the heated medium into the tank can be controlled based on the liquid level in the tank.

  Further, the steam generation system of the present invention may further include a nozzle that supplies the liquid to-be-heated medium to the steam of the medium to be heated.

  In this case, the nozzle can be arranged at the inlet and / or outlet of the compressor.

  In this case, the nozzle may be arranged between the stages of the compressor.

According to the steam generation system of the present invention, energy efficiency can be improved by utilizing a heat pump.
In addition, the heating temperature region can be set relatively narrow under the condition of the negative pressure state, and the heat pump can be used at a high COP.

  Hereinafter, a steam generation system according to the present invention will be described with reference to the drawings.

FIG. 1 is a schematic diagram showing a configuration of a steam generation system according to the present invention.
In FIG. 1, the steam generation system S <b> 1 includes a heat pump 10, a heating medium (for example, water) supply path 20, and a compressor 30.

  The heat pump 10 is a device that pumps heat from a low-temperature object and applies heat to a high-temperature object by a cycle including evaporation, compression, condensation, and expansion processes. Heat pumps generally have the advantage of being relatively high in energy efficiency and, as a result, relatively low in emissions of carbon dioxide and the like and being environmentally friendly.

  Specifically, the heat pump 10 has a heat absorption part 11, a compression part 12, a heat radiation part 13, and an expansion part 14, which are sequentially connected via a pipe. The heat absorbing unit 11 has an endothermic function, and absorbs heat corresponding to the absorbed heat from a heat source outside the cycle when the heat medium absorbs heat. The heat dissipating unit 13 has a heat dissipating function. When the heat medium dissipates heat, the heat dissipating unit 13 gives heat corresponding to the released heat to a heat source outside the cycle. The compression unit 12 compresses the heat medium using a compressor or the like. At this time, the temperature of the heat medium usually increases. Power is supplied to the compression unit 12. The expansion unit 14 expands the heat medium by a pressure reducing valve, a turbine, or the like. At this time, the temperature of the heat medium usually decreases. When a turbine is used, power can be taken out from the expansion unit 14, and the power may be supplied to the compression unit 12, for example. As the heat medium used in the heat pump 10, various known heat mediums such as a fluorocarbon medium, ammonia, water, carbon dioxide, and air are applied.

  The supply path 20 includes a tank 21 that stores the liquid medium to be heated, and a duct 22 that connects the tank 21 and the compressor 30.

  The tank 21 is provided with a supply port 25 and a discharge port 26. A liquid medium to be heated is supplied to the tank 21 through the supply port 25. The supply amount of the heated medium to the tank 21 is controlled so that the liquid level in the tank 21 is within a predetermined range. For example, based on the measurement result of a sensor (not shown) that measures the liquid level in the tank 21, the output of the heating medium supply power source 27 is controlled.

  A heat radiating portion 13 of the heat pump 10 is disposed at a liquid phase position in the tank 21. The heat radiating part 13 of the heat pump 10 may or may not be in direct contact with the liquid in the tank 21. The liquid phase of the medium to be heated in the tank 21 is heated by heat exchange with the heat radiating unit 13. The arrangement position of the discharge port 26 is a gas phase (vapor phase) position in the tank 21. The internal space of the tank 21 is sucked by the compressor 30 through the discharge port 26 and the duct 22. The steam generated in the tank 21 flows in the duct 22 toward the compressor 30 through the discharge port 26.

  The compressor 30 is disposed on the supply path 20 and is disposed downstream of the tank 21. As the compressor 30, various compressors such as an axial compressor, a centrifugal compressor, a reciprocating compressor, and a rotary compressor are applied, and it is preferable to be suitable for vapor compression. The compressor 30 compresses the steam from the tank 21 and flows the pressurized steam downstream.

  Further, the compressor 30 (or the supply path 20) is provided with a nozzle 35 for supplying a liquid medium to be heated to the steam as necessary. The arrangement position of the nozzle 35 is, for example, at least one of an inlet and an outlet of the compressor 30. When the compressor 30 is a multistage type, the spray nozzle 35 can also be arrange | positioned between stages. A pipe configuration in which the nozzle 35 and the liquid phase position of the tank 21 are connected via a pipe 36 can be used, and in this pipe configuration, the liquid in the tank 21 having a relatively high temperature is effectively used for the supply. For discharging the liquid from the nozzle 35, a power source such as a pump may be used, or a pressure difference between the inlet and the outlet of the pipe may be used.

  By the suction action by the compressor 30, the internal space at the heating position by the heat pump 10 in the supply path 20, that is, the internal space of the tank 21 is decompressed. Control valves (such as a flow rate control valve, not shown) and the compressor 30 on the supply path 20 are controlled so that the internal pressure of the tank 21 becomes a negative pressure (negative pressure) lower than the atmospheric pressure. This control is performed based on a measurement result of a sensor (not shown) that measures the internal pressure of the tank 21, for example.

  The tank 21 and the heat pump 10 are designed (capacity design, capacity design, etc.) so that the liquid medium to be heated evaporates when the internal space of the tank 21 is in a negative pressure state. The coefficient of performance of the heat pump 10 changes according to the difference between the input temperature and the output temperature of the medium to be heated. If the temperature difference is excessively large, the coefficient of performance (COP) may decrease. Under the condition that the internal space of the tank 21 is in a negative pressure state, the heating temperature region can be set relatively narrow, and the heat pump 10 can be used at a high COP.

  In the steam generation system S <b> 1 of this example, the medium to be heated in the supply path 20 becomes steam at a relatively low pressure and low temperature when heated by the heat pump 10, and steam at a relatively high pressure and high temperature when compressed by the compressor 30. It becomes. That is, the medium to be heated heated by the heat pump 10 is further heated by compression by the compressor 30. The steam from the steam generation system S1 is supplied to a predetermined external facility such as a manufacturing plant, a cooking facility, an air conditioning facility, a power plant, and the like.

  Since the compressor 30 supplements a part of the heating temperature region for generating steam, the heat pump 10 is used at a high COP. Therefore, in the steam generation system S1 of this example, high energy efficiency can be obtained as compared with the boiler by two-stage sequential heating using the heat pump 10 and the compressor 30. Further, since the compressor 30 is used in the second stage of heating, the configuration is relatively simple.

  Here, a trial calculation example is shown. When the water heating temperature range is 20 ° C. to 161 ° C. (saturated steam of 0.8 MPa), in the steam generation system S1 of this example, the primary input energy is reduced by about 14% compared to the boiler. Reduction of primary input energy is effective in reducing CO2 emissions from facilities such as factories. In the above calculation, the boiler efficiency is 80%, the COP of the heat pump is 4, and the power generation efficiency (including the power transmission end and the power transmission loss) is 38%. Moreover, the primary input energy of the boiler was obtained from the amount of heat of fuel, and the primary input energy of the heat pump was obtained by converting electric power into fuel. When the COP of the heat pump is 3, the reduction rate of the primary input energy with respect to the boiler is about 4%.

FIG. 2 is a Ts diagram showing an example of a change in the state of water by the steam generation system S1 of this example.
As shown in FIG. 2, first, water becomes saturated steam d0 by heating with a heat pump in a state of negative pressure P0 lower than atmospheric pressure (P1 = 1 atm = about 0.1 MPa). The temperature of the saturated vapor d0 is lower than the normal boiling point, for example 90 ° C.

  Next, the saturated steam d0 becomes a relatively high-pressure and high-temperature steam (superheated steam e2) by compression by the compressor. That is, the temperature of the steam rises with the compression. The pressure P2 of the superheated steam e2 is higher than atmospheric pressure, for example, 0.8 MPa.

  A saturated steam of about 160 ° C. can be obtained by cooling the superheated steam e2 of 0.8 MPa under a constant pressure (dashed line a in FIG. 2). Similarly, saturated steam d1 at about 100 ° C. can be obtained by cooling superheated steam at atmospheric pressure (about 0.1 MPa) under constant pressure.

  By directly mixing liquid water or warm water into the cooling from the superheated steam to the saturated steam, the volume of the steam is increased. In this case, for example, water or hot water is supplied to the steam at the outlet of the compressor.

  Furthermore, by optimizing the supply amount and timing of water or hot water, the change from the relatively low pressure and low temperature saturated steam d0 to the relatively high pressure and high temperature saturated steam d2 can be made more direct. For example, when an appropriate amount of water or warm water is supplied to the steam at the compressor inlet and / or in the middle, the saturated steam d0 at the compressor inlet is changed to saturated steam d2 at the compressor outlet (FIG. 2). Dashed line b). That is, by optimizing the combination of compression by the compressor and cooling by water or hot water, steam close to saturation can be discharged from the compressor.

  Thus, in the steam generation system S1 of this example, both saturated steam and superheated steam can be easily generated by two-stage sequential heating using the heat pump 10 and the compressor 30. That is, after generating saturated steam at a negative pressure lower than the atmospheric pressure by heating by the heat pump 10, superheated steam or saturated steam at a pressure higher than atmospheric pressure or atmospheric pressure is generated by compression by the compressor 30. be able to. Therefore, the steam generation system S1 of this example is highly flexible with respect to the steam specifications.

  Furthermore, the steam generation system S1 of this example is suitable for obtaining high-temperature steam exceeding 100 ° C. In other words, since the compressor 30 is used for heating in the relatively high temperature range of the medium to be heated, the temperature rise can be shortened and heat loss can be suppressed as compared with heating by heat transfer.

  In addition, the numerical value used in the said description is an example, Comprising: This invention is not limited to this.

3, 4, and 5 are configuration examples of the tank 21 shown in FIG. 1.
In the example of FIG. 3, the tank 21 has a box-shaped reservoir 41. The lower part in the reservoir 41 is the liquid phase of the medium to be heated, and the upper part is the gas phase (vapor phase) of the medium to be heated. A heated medium supply port 25 is provided on the bottom surface or side surface of the reservoir 41, and a heated medium discharge port 26 is provided on the upper surface (gas phase position) of the reservoir 41. Further, the heat radiating portion 13 of the heat pump 10 is disposed at the liquid phase position inside the reservoir portion 41.

  In the tank 21 of FIG. 3, the liquid heated medium is stored in the lower part of the storage unit 41, and the heated medium is heated by heat exchange with the heat radiating unit 13 of the heat pump 10. Then, the generated steam is sucked into the compressor 30 (see FIG. 1) through the discharge port 26 of the reservoir 41.

  In the example of FIG. 4, the tank 21 has a cylindrical reservoir 45. The axial direction of the cylindrical reservoir 45 is parallel to the gravity direction or inclined with respect to the gravity direction. A heated medium supply port 25 is provided at the lower end of the reservoir 45, and a heated medium discharge port 26 is provided at the upper end (gas phase position). Further, the heat radiating portion 13 of the heat pump 10 is disposed in the storage portion 45 along the axial direction thereof. The heat dissipation part 13 of the heat pump 10 may be configured to be wound along the outer peripheral surface of the cylindrical storage part 45 and the axial direction.

  In the tank 21 of FIG. 4, a liquid heated medium is stored in a cylindrical storage section 45, and the heated medium is heated by heat exchange with the heat radiating section 13 of the heat pump 10. Then, the generated steam is sucked into the compressor 30 (see FIG. 1) through the discharge port 26 of the reservoir 45. Further, the temperature of the medium to be heated rises from bottom to top along the axial direction of the reservoir 45.

  In the example of FIG. 5, the tank 21 has a circulation pipe 48 in addition to the reservoir 47. A supply port 25 for a medium to be heated is provided in the reservoir 47 or the circulation pipe 48, and a discharge port 26 is provided on the upper surface (gas phase position) of the reservoir 47. The inlet end 48 a of the circulation pipe 48 is connected to the bottom surface of the reservoir 47, and the other outlet end 48 b is connected to the upper surface (gas phase position) of the reservoir 47. Further, the heat radiating portion 13 of the heat pump 10 is wound around the outer peripheral surface of the circulation pipe 48. A configuration in which a gas-liquid separator is disposed adjacent to the outlet end 48 b of the circulation pipe 48 may be employed. The heat dissipating part 13 of the heat pump 10 may be arranged inside the circulation pipe 48.

  In the tank 21 of FIG. 5, the liquid heated medium is stored in the reservoir 47 and the circulation pipe 48, and the heated medium in the circulation pipe 48 is heated by heat exchange with the heat radiating part 13 of the heat pump 10. . Along with this heat change, the medium to be heated flows in the circulation pipe 48 from the inlet end 48a toward the outlet end 48b. Of the heated medium discharged from the circulation pipe 48, the vapor is sucked into the compressor 30 (see FIG. 1) through the discharge port 26 of the storage unit 47, and the liquid is stored in the storage unit 47.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to these embodiments. Additions, omissions, substitutions, and other modifications can be made without departing from the spirit of the present invention. The present invention is not limited by the above description, but only by the scope of the appended claims.

It is the schematic which shows the structure of the steam generation system which concerns on this invention. It is a Ts diagram which shows an example of the state change of the water by a steam generation system. It is a structural example of a tank. It is another example of composition of a tank. It is another structural example of a tank.

Explanation of symbols

  DESCRIPTION OF SYMBOLS S1 ... Steam generation system S1, 10 ... Heat pump, 11 ... Endothermic part, 12 ... Compression part, 13 ... Radiation part, 14 ... Expansion part, 20 ... Supply path, 21 ... Tank, 22 ... Duct, 25 ... Supply port, 26 DESCRIPTION OF SYMBOLS ... Discharge port, 27 ... Supply power source, 30 ... Compressor, 35 ... Nozzle, 36 ... Pipe, 41, 45, 47 ... Storage part, 48a ... Inlet end, 48b ... Outlet end, 48 ... Circulation piping.

Claims (7)

A heating medium supply path;
A heat pump for heating the heated medium in the supply path;
A compressor arranged on the supply path and compressing the heated medium heated by the heat pump ,
The heated medium in the supply path becomes saturated steam at a negative pressure lower than atmospheric pressure by heating by the heat pump, and becomes steam at atmospheric pressure or pressure higher than atmospheric pressure by compression by the compressor. A steam generation system characterized by that. The steam generation system according to claim 1 , wherein the supply path includes a tank that stores the liquid medium to be heated. The steam generation system according to claim 2 , wherein a gas phase in the tank is sucked into the compressor, and a liquid phase in the tank is heated by the heat pump in or outside the tank. . The steam generation system according to claim 1 or 2 , wherein the supply amount of the heated medium into the tank is controlled based on a liquid level in the tank. The steam generation system according to claim 1 , further comprising a nozzle that supplies the liquid to be heated with respect to the vapor of the medium to be heated. The steam generation system according to claim 5 , wherein the nozzle is disposed at an inlet and / or an outlet of the compressor. The steam generation system according to claim 5 or 6 , wherein the nozzle is disposed between stages of the compressor.

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