JPS60169608A - Turbine plant utilizing hot water - Google Patents

Abstract

PURPOSE:To improve the efficiency of entire plant by providing an once-through evaporator operatable under low dryness region of working liquid and a mist evaporator operatable under high dryness region. CONSTITUTION:Hot water pumped through a hot water pump 1 will pass sequentially through mist evaporator 2, once-through evaporator 3 and preheater 4 to be returned to the underground. Mixture medium of more than two components is pressurized by working fluid pump 5 to be fed to preheater 4, once-through evaporator 3 and mist evaporator 2. The working fluid is heated by once- through evaporator 3 to produce wet steam having the dryness of approximately 0.8-0.9. Steam flowed out of the mist evaporator 2 is fed to a turbine 6. The evaporators 2, 3 are counter-flow type. In such a manner, the heat-exchange efficiency is improved resulting in considerable improvement of the efficiency of entire plant.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention uses hot water such as geothermal hot water or surface seawater as a high-temperature heat source, and uses two or more types of low-boiling point hydrocarbons, fluorocarbons, etc. in an appropriate ratio. The present invention relates to a turbine plant that uses a mixture as a working fluid.

[Technical background of the invention and its problems] In recent years, in power plants that use the thermal energy of geothermal hot water as an island heat source for turbine cycles such as Rankine cycles, two or more types of low boiling point carbonization are used. It has been considered to configure a system using a so-called mixed medium, which is a mixture of hydrogen, fluorocarbon, etc., as a working fluid. This mixed medium has the characteristic that the evaporation temperature increases as it evaporates, so more heat energy can be recovered from hot water with less working fluid circulation than in the case of a single component working fluid. This has the advantage that it is possible to reduce in-house power such as pump power, and a large output can be obtained at the sending end.

However, in order to bring out the characteristics of this mixed medium, changes in the temperature of the mixed medium are caused by differences in the evaporation rate or condensation rate of the components during the evaporation or condensation process, and are accompanied by changes in the composition of liquid and vapor. Therefore, the evaporator or condenser must be a completely countercurrent, once-through heat exchanger.

However, in heat exchangers that flow the working fluid inside the heat transfer tubes or outside the heat transfer tubes, the dryness of the steam during the evaporation process is between 0.8 and 0.
．． When the temperature rises to about 9, the heat transfer surface is no longer wetted by the liquid and boiling does not occur on the heat transfer surface, resulting in an extremely poor heat transfer coefficient, and complete vaporization of the working fluid is impossible. There are problems such as the liquid remaining in the form of droplets (mist). Therefore, before sending the steam obtained from the evaporator to the turbine, it is necessary to separate the mist using a mist separator. Therefore, all of the working fluid fed to the evaporator cannot be used to drive the turbine, resulting in disadvantages such as lower efficiency of the entire plant.

[Purpose of the invention]

In view of these points, the present invention completely evaporates the mist in the working fluid fed to the evaporator, so that all of the working fluid can be used to drive the turbine, and the characteristics of the mixed medium are maximized. The purpose of the present invention is to obtain a hot water utilization turbine plant that can be utilized for various purposes and improve the efficiency of the entire plant.

[Summary of the invention]

The present invention provides a hot water turbine plant that utilizes geothermal drought or the like as a high-temperature heat source and configures a turbine cycle using a mixed medium of two or more components as a working fluid.
The flow direction of the fluid in all heat exchangers involved in the temperature raising and evaporation process from liquid to steam of the working fluid is set to counter-flow type, and the flow direction of the fluid in all heat exchangers involved in the process of heating up and evaporating the working fluid from liquid to steam is of the counter-flow type. The evaporator involved is
It is characterized by being configured with a once-through type evaporator that operates in the region, and a mist evaporator that operates in the region where the working fluid is highly dry, with a mist collection layer provided on the outside of the heat transfer tube in the main body shell. do.

[Embodiments of the invention]

Hereinafter, one embodiment of the present invention will be described with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 denotes a hot water pump that pumps hot water etc. heated by geothermal heat. The water is returned to the ground in sequence.

On the other hand, reference numeral 5 denotes a working fluid pump, in which a working fluid containing two or more types of low boiling point hydrocarbons, fluorocarbons, etc. mixed in an appropriate ratio is pressurized by the working fluid pump 5 and preheated in a subcooled liquid state. The water is supplied to the vessel 4 and then sequentially to the once-through evaporator 3 and the mist evaporator 2. The mist evaporator 2, once-through evaporator 3, and preheater 4 are completely counterflow types, and the working fluid that first flows into the preheater 4 undergoes heat exchange with hot water in the preheater 4. The temperature is raised to reach the saturation temperature. The temperature of the working fluid that has reached the saturation temperature increases while evaporating in the once-through evaporator 3, and the dryness level increases from 0.8 to 0.8.
The air is heated until it reaches a temperature of about 0.9℃, and is then supplied to the mist evaporator 2.

By the way, near the outlet of the once-through type evaporator 3, the working fluid is steam containing a large amount of droplets (mist), and if this is heated with a normal once-through type evaporator, the heat transfer rate will be poor. Therefore, a large heat transfer area is required. Therefore, according to the present invention, the mist is removed from the once-through type evaporator before the heat transfer coefficient decreases and introduced into the mist evaporator 2 suitable for heating the steam containing lυ.

FIG. 2 is a longitudinal sectional view of the mist evaporator 2, in which a hot water inlet side water chamber 22 is provided at the lower end of the main body body 21, and a hot water outlet side ice chamber 23 is provided at the upper end. . Inside the main body shell 21, a large number of parallel heat exchanger tubes 25 are disposed with both ends attached to tube plates 24 and 24, respectively, and a plurality of baffle plates 26 orthogonal to the heat exchanger tubes 25 are arranged in a zigzag shape. Further, an inlet 27 and an outlet 28 for the working fluid are formed in the upper part J3 and the lower part of the main body shell 21, respectively.

Further, in the space within the main body 1121, that is, on the outer side of the heat exchanger tube 25, a mist collection layer 29 made of a multilayer wire mesh layer is arranged so that at least a part thereof is in contact with the outer surface of the heat exchanger tube 25.

That is, as shown in FIG. 3, a mist collection layer 29 made of a layer of sheet metal is arranged parallel to the heat transfer @25,
Both sides of the wire mesh layer are in contact with the heat exchanger tubes 25, and at least a portion of the two mist collection layers is in contact with a portion of the surface of the heat exchanger tube 25, or as shown in FIG. As shown in FIG. 5, a mist collection layer 29 made of a wire mesh layer is provided concentrically on the outer periphery of the heat exchanger tube 25, or two mist collection layers 29 are provided perpendicularly to the heat exchanger tube 25 as shown in FIG. is provided, and the heat transfer tube 25 penetrates through the mist collection layer 29.

Therefore, the working fluid vapor containing the mistake i~ supplied from the penetrating wave evaporator 3 to the main body shell 21 via the working fluid population 27 flows down inside the main body shell 21, while opposing the flow of the working fluid vapor. The working fluid is heated by exchanging heat with the hot water flowing in the heat transfer tube 25 in the direction, and flows out from the working fluid outlet 28. by the way,
The mist portion of the working fluid that has entered the main body shell 21 from the working fluid inlet 27 is gradually collected by the mist collecting layer 29 . Therefore, the collected mist reaches the surface of the heat exchanger tube 25 due to the shear force and surface tension of the steam, where it is heated by the dry water in the heat exchanger tube 25, evaporates, and becomes vaporized.

In this way, the mist in the working fluid evaporates and becomes steam, but the mist that originally entered the main body shell 1 as steam also touches the heat transfer tube 25 and is gradually heated in the flow direction, becoming saturated. temperature or higher. Therefore, even if there is mist that is trapped in the mist collection layer 29 but cannot reach the surface of the heat transfer tube, it will be heated by the high temperature steam that flows one after another.
It becomes steam. In this case, since the length of the flow path through which the working fluid flows is sufficiently long, the mesh of the wire mesh does not need to be extremely narrow, and the pressure loss of the working fluid can be small.

In this way, the temperature of the steam containing mist gradually rises in the flow direction, but since the flow is almost completely countercurrent to the flow direction of the hot water, the temperature difference with the hot water is always maintained large, increasing the heat exchange rate. is large, and the mist in the working fluid in the mist evaporator 2 is completely evaporated, and the steam flowing out from the mist evaporator 2 is fed to the turbine 6.

The steam sent to the turbine 6 performs work there to drive the generator 7, and the steam that has completed its work in the turbine 6 is condensed in the condenser 8 and flows into the hot well tank 9, after which the working fluid is The pump 5 sends it again to the preheater 4.

On the other hand, cooling water cooled by a cooling tower 10 is sent to the condenser 8 by a cooling water pump 11, and the cooling water condenses the air from the turbine 6.

(Effects of the Invention) As explained above, in the present invention, since both of the generators are self-flow type, it is possible to always maintain a large temperature difference between the heat source fluid and the working fluid in each evaporator. By increasing the heat exchange efficiency and reducing the heat transfer area, the evaporator can be made smaller.Moreover, it operates in an area where the working fluid containing mist is highly dry, and the mist can be effectively evaporated. Since the cooling mist evaporator is installed next to the ordinary once-through evaporator, all of the working fluid sent by the working fluid pump is supplied to the turbine in the form of steam, reducing the pump power and reducing the steam flow rate. The turbine efficiency can also be improved, and the efficiency of the entire plant can be greatly improved.

[Brief explanation of drawings]

FIG. 1 is a schematic system diagram of a plant according to the present invention, FIG. 2 is a vertical cross-sectional view of a mist evaporator, and FIGS. 3 to 5 are explanatory diagrams of a mist trapping layer. 2...Mist evaporator, 3...Noble flow evaporator, 4...
- Preheater, 5... Working fluid pump, 6... Turbine, 8... Condenser, 21... Main body shell, 25... Heat transfer tube, 29... Mist collection layer. Applicant's agent Ino Wataru Figure 1 Figure 2 Figure 3 Item 9 Procedural amendment April 11, 1980 Commissioner of the Patent Office Kazuo Wakasugi (Examiner) 1 Indication of the case 1980 Patent Application No. 26397 2 Name of the invention Drought water utilization turbine plan 1 to 3 Relationship with the case of the person making the amendment Patent applicant (307) Toshiba Corporation 4 Agent 2-3 Marunouchi Atsushi-chome, Chiyoda-ku, Tokyo Telephone Tokyo (211) 2321 Major Representative 4230 Patent Attorney Ino Setsei 5 "Detailed Description of the Invention" column of the dated specification of the amendment order. 8. In the statement of contents of the amendment, page 3, line 20, [caused, liquid and vapor j] is corrected as [caused liquid and vapor J.

Claims (1)

[Claims] 1. Geothermal hot water, etc. is used as a high-temperature heat source, and 2.
In a hot water turbine plant where a turbine cycle is constructed using a mixed medium containing more than the components as a working fluid, the flow direction of the fluid in all heat exchangers involved in the temperature raising and evaporation process of the working fluid from liquid to steam is reverse flow. Along with making a mold,
The evaporator involved in the evaporation process from working fluid saturated liquid to dry saturated steam is divided into a once-through type evaporator that operates in an area where the working fluid is less dry, and a mist trap on the outside of the heat transfer tube inside the main body shell. A drought utilization turbine plant characterized by comprising a mist evaporator that operates in a region where a working fluid has a high degree of dryness and is provided with a condensed layer. 2. The drought utilization turbine plant according to claim 1, wherein the mist collection layer is a wire mesh layer. 3. The hot water utilization turbine plant according to claim 1, wherein the mist collection layer is a large number of plate-shaped wire meshes arranged in parallel with the heat transfer tubes. 4. The drought water utilization turbine plant according to claim 1, wherein the mist collection layer is a wire mesh layer arranged concentrically with the heat transfer tube. 5. The hot water utilization turbine plant according to claim 1, wherein the mist collection layer is a wire mesh layer arranged in a plane perpendicular to the heat transfer tubes. 6. The hot water is geothermal hot water. Which of claims M1 to 5 is the drought utilization turbine plan 1-0 according to claim 1? 7. The hot water is surface seawater of the ocean. Hot water utilization turbine plans 1 to 1 according to any one of claims 1 to 5.