Efficient steam power circulation system

Abstract

The invention relates to the technical field of circulating power machinery, and provides an efficient steam power circulating system which comprises a steam generator, a steam turbine unit, a condenser, a cooler, a reverse osmosis saline water separation device and a hydraulic turbine unit. An output port of the steam generator is communicated with an input port of the turboset, an output port of the turboset is communicated with an input port of the condenser, the reverse osmosis saline water separation device is provided with a pure water output port and a separated solution output port, and the pure water output port is communicated with a pure water input port of the steam generator; the separation solution output port is communicated with the hydraulic turbine unit, the hydraulic turbine unit is communicated with the cooler, and a cooling medium is a water-based absorbent; and the pressurizing flow path is provided with a pressurizing pump. The cooling medium in the cooling circulation loop is set to be the water-based absorbent, so that under the condition that the temperature of an environment cold source is certain, the steam pressure in the condenser can be greatly reduced, the power output of a steam turbine is improved, the heat efficiency of a circulation system is improved, the transformation difficulty of an existing system is lowered, and the cost is low.

Description

Technical Field

[0001] The invention relates to the technical field of circulating power machinery, and in particular to a high-efficiency steam power circulating system. Background Art

[0002] The steam Rankine cycle system with water as the medium is widely used in the field of energy and power engineering technology. The steam Rankine cycle system converts thermal energy into mechanical energy to provide power or be used for power generation.

[0003] In order to meet the requirements of energy conservation and environmental protection and improve the thermal efficiency of the steam Rankine cycle system, the most direct way is to increase the maximum temperature of the circulation system or reduce the minimum pressure of the circulation system. The maximum temperature of the circulation system is limited by the temperature of the heat source and the temperature resistance of the material, and it is difficult to increase. The lowest pressure of the circulation system is located in the condenser. Since the medium discharged into the condenser by the turbine is saturated steam, the minimum pressure is directly related to the minimum temperature. Therefore, reducing the medium pressure means reducing the temperature, which also makes it difficult to implement. In addition, it is limited by the spatial volume of each component in the system, resulting in limited improvement effect. Summary of the invention

[0004] The present invention provides a high-efficiency steam power cycle system, which is used to solve the defects of the prior art that the thermal efficiency is difficult to improve and the improvement effect is limited.

[0005] The present invention provides a high-efficiency steam power cycle system, comprising: a steam generator, a steam turbine unit, a condenser, a cooler, a reverse osmosis brine separation device and a hydraulic turbine unit; the steam output port of the steam generator is connected to the steam input port of the steam turbine unit, the steam-water mixed output port of the steam turbine unit is connected to the steam-water mixed input port of the condenser, the cooling medium mixed output port of the condenser is connected to the cooling medium mixed input port of the reverse osmosis brine separation device through a boosting flow path; and the reverse osmosis brine separation device has a pure water output port and a separation solution output port, the pure water output port is connected to the pure water input port of the steam generator to form a steam circulation loop; the separation solution output port is connected to the medium input port of the hydraulic turbine unit, the medium output port of the hydraulic turbine unit is connected to the cooling medium input port of the cooler, the cooling medium output port of the cooler is connected to the condenser to form a cooling circulation loop, and the cooling medium in the cooling circulation loop is a water-based absorbent; wherein the boosting flow path is provided with a boosting pump.

[0006] According to the high-efficiency steam power cycle system provided by the present invention, both the steam turbine unit and the hydraulic turbine unit are connected to a load.

[0007] According to the high-efficiency steam power cycle system provided by the present invention, the load includes a driving device or a generator set.

[0008] According to the high-efficiency steam power cycle system provided by the present invention, a condensate pump and a feed water pump are sequentially arranged on the pressurized flow path along the medium flow direction.

[0009] According to the high-efficiency steam power cycle system provided by the present invention, a cooling branch is provided between the condensate pump and the feed water pump, one end of the cooling branch is connected to the boost flow path, and the other end of the cooling branch is connected to the cooling medium input port of the cooler, so that a part of the cooling medium output through the condensate pump is transported to the cooler by the cooling branch, and the remaining part of the cooling medium is input into the reverse osmosis brine separation device by the feed water pump.

[0010] According to the high-efficiency steam power cycle system provided by the present invention, the outlet pressure of the feed water pump is greater than the outlet pressure of the condensate pump.

[0011] According to the high-efficiency steam power cycle system provided by the present invention, the water-based absorbent includes a salt water solution.

[0012] According to the high-efficiency steam power cycle system provided by the present invention, the solute of the brine solution includes lithium bromide.

[0013] According to the high-efficiency steam power cycle system provided by the present invention, the condenser includes a spray condenser, and the spray device in the spray condenser is connected to the cooling medium output port of the cooler.

[0014] According to the high-efficiency steam power cycle system provided by the present invention, the cooler includes a shell and tube heat exchanger.

[0015] The present invention provides a high-efficiency steam power cycle system, which can significantly reduce the saturated steam pressure in the condenser, improve the turbine output, and increase the thermal efficiency of the cycle system by setting the cooling medium in the cooling cycle loop as a water-based absorbent, under the condition of a constant ambient cold source temperature. In addition, the present invention can facilitate the improvement of existing equipment by changing the cooling medium, and the difficulty and cost of transformation are low. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0017] Figure 1 It is a structural schematic diagram of the high-efficiency steam power cycle system provided by the present invention.

[0018] Reference numerals: 1. Steam generator; 2. Steam turbine unit; 3. Condenser; 4. Condensate pump; 5. Cooler; 6. Feed water pump; 7. Reverse osmosis brine separation device; 8. Hydraulic turbine unit. DETAILED DESCRIPTION

[0019] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of explaining the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0021] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0022] In the embodiments of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0023] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiment of the present invention. In this specification, the schematic representations of the above terms are not necessarily for the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0024] Steam Rankine cycle systems are widely used in the fields of energy and power engineering technology. They usually use water as a medium for recycling, so that they can provide power or be used for power generation. In steam Rankine cycle systems, how to improve the thermal efficiency of the system has been a long-term exploration and solution in the industry.

[0025] In the related art, there are two ways to improve the thermal efficiency of the system: to increase the maximum temperature of the circulation system or to reduce the minimum pressure of the circulation system. However, it is difficult to increase the upper limit of the maximum temperature of the circulation system, and it is difficult to improve the original system. For the method of reducing the minimum pressure of the circulation system, since the medium temperature is limited by the cooling capacity that the ambient cold source can provide to the condenser, under the condition of constant ambient temperature, in order to reduce the medium pressure in the condenser, the heat exchange area needs to be increased, thereby increasing the volume of the condenser, the construction cost and the cooling water / cooling air flow demand. At the same time, there is an upper limit to the effect of this method, that is, the medium temperature in the condenser cannot be lower than the ambient cold source temperature, and thus the medium pressure cannot be lower than the saturation pressure corresponding to the ambient cold source temperature. And even if it is a limited improvement in the thermal efficiency improvement method, since the changes to the entire system are large, this is not conducive to the transformation of the existing system, greatly increasing the difficulty and cost of the transformation, making the transformation of the existing system limited.

[0026] Regarding the problems in related technologies, such as Figure 1As shown, a high-efficiency steam power cycle system provided by the present invention comprises a steam generator 1, a steam turbine unit 2, a condenser 3, a cooler 5, a reverse osmosis brine separation device 7 and a hydraulic turbine unit 8; the steam output port of the steam generator 1 is connected to the steam input port of the steam turbine unit 2, the steam-water mixed output port of the steam turbine unit 2 is connected to the steam-water mixed input port of the condenser 3, the cooling medium mixed output port of the condenser 3 is connected to the cooling medium mixed input port of the reverse osmosis brine separation device 7 through a boosting flow path; and the reverse osmosis brine separation device 7 has a pure water output port and a separation solution output port, the pure water output port is connected to the pure water input port of the steam generator 1 to form a steam circulation loop; the separation solution output port is connected to the medium input port of the hydraulic turbine unit 8, the medium output port of the hydraulic turbine unit 8 is connected to the cooling medium input port of the cooler 5, the cooling medium output port of the cooler 5 is connected to the condenser 3 to form a cooling circulation loop, and the cooling medium in the cooling circulation loop is a water-based absorbent; wherein the boosting flow path is provided with a boosting pump. When improving the thermal efficiency of the system, it is mainly achieved by reducing the pressure in the condenser 3. In this embodiment, by setting the cooling medium to a water-based absorbent, which has absorption characteristics, the saturated vapor pressure is lower than the saturated vapor pressure of pure water at the same temperature, thereby greatly reducing the steam pressure in the condenser, increasing the output power of the steam turbine unit 2, and improving the thermal efficiency of the circulation system.

[0027] Specifically, the steam generator 1, the steam turbine unit 2, the condenser 3 and the reverse osmosis brine separation device 7 are connected end to end in sequence to form a steam circulation loop, and the utilization of steam thermal energy is realized in the steam circulation loop. The end-to-end connection means that the input port of each downstream device is connected to the output port of the upstream device to form the entire circulation loop in sequence.

[0028] For example, the pure water input port of the steam generator 1 is connected to the pure water output port of the reverse osmosis salt water separation device 7, thereby achieving communication between the upstream and downstream.

[0029] The cooler 5, the condenser 3, the reverse osmosis brine separation device 7 and the hydraulic turbine unit 8 are connected end to end in sequence to form a cooling circulation loop. The cooling circulation loop can improve the circulation efficiency of the steam in the system, and achieve efficient cooling by contacting the cooling medium with the steam-water mixture in the condenser 3, thereby improving the steam circulation efficiency.

[0030] It is understandable that in the scheme of this embodiment, the cooling medium is replaced with a water-based absorbent, and the water-based absorbent is isolated by the reverse osmosis brine separation device 7 to prevent the water-based absorbent from entering the steam circulation loop. This arrangement can make full use of the existing steam Rankine cycle system, and only a small amount of modification is required based on the existing power plant steam Rankine cycle system, in which the steam turbine unit 2, steam generator 1 and other equipment do not need any modification, and the condenser, booster pump and other equipment only need to replace the medium from water to a water-based absorbent solution for component-level material replacement, and the only new equipment is the reverse osmosis brine separation device 7 and the hydraulic turbine unit 8. This greatly reduces the difficulty of improving the existing system and reduces the cost of modification.

[0031] According to some embodiments provided by the present invention, the steam turbine unit 2 and the hydraulic turbine unit 8 are both connected to a load. The setting of the load can realize the conversion of thermal energy to realize the circulation of the system. In this embodiment, by connecting the steam turbine unit 2 and the hydraulic turbine unit 8 to a load, efficient energy conversion is realized, and the energy conversion rate of the system is improved.

[0032] It is understandable that in the steam Rankine cycle system of the transmission, a load is usually only set at the output end of the steam turbine unit 2. In this example, by also setting a load on the hydraulic turbine unit 8 in the cooling cycle, the conversion rate of thermal energy can be increased.

[0033] In specific settings, the load includes a drive device or a generator set. When the load is a drive device, it can convert thermal energy into kinetic energy to achieve efficient energy conversion. When the load is a generator set, it can directly convert thermal energy into electrical energy to achieve efficient thermal energy conversion.

[0034] According to some embodiments provided by the present invention, a condensate pump 4 and a feed water pump 6 are sequentially arranged on the boosting flow path along the medium flow direction. After the high-temperature and high-pressure steam in the steam turbine unit 2 works, a low-temperature and low-pressure steam-water mixture is formed, which can be cooled by contacting with the cooling medium in the condenser 3, causing it to condense into liquid. This makes the output of the condenser 3 a low-temperature and low-pressure cooling medium mixed liquid, which is a water-based absorbent mixed liquid with a low concentration, and needs to be pressurized by the condensate pump 4 and the feed water pump 6 to achieve high-efficiency circulation of the entire circulation system.

[0035] It can be understood that the provision of two booster pumps can improve the efficient circulation of the entire circulation system, increase the circulation rate, and facilitate the separation of water in the subsequent reverse osmosis brine separation device 7.

[0036] In the specific setting, the outlet pressure of the water supply pump 6 is greater than the outlet pressure of the condensate pump 4. That is, the cooling medium mixed solution is pressurized by the first stage of the condensate pump 4 and then output by the second stage of the water supply pump 6, so that the cooling medium mixed solution output by the water supply pump 6 has a higher pressure, which is conducive to the separation of pure water in the reverse osmosis brine separation device 7.

[0037] It can be understood that the reverse osmosis brine separation device 7 needs to rely on applying pressure to overcome the osmotic pressure of the solution, thereby pushing water molecules through the reverse osmosis membrane, while leaving salt and other solutes on one side of the membrane. In this embodiment, the cooling medium mixed solution can be pressurized by the setting of the water feed pump 6, and a separation solution output port is provided on the reverse osmosis brine separation device 7, so that the cooling medium can be output to the hydraulic turbine unit 8 to perform work, thereby realizing efficient energy utilization and improving the utilization efficiency of thermal energy in the overall system.

[0038] In some embodiments, a cooling branch is provided between the condensate pump 4 and the feed water pump 6, one end of the cooling branch is connected to the boosting flow path, and the other end of the cooling branch is connected to the input port of the cooler 5, so that a part of the cooling medium mixed solution output by the condensate pump 4 is transported to the cooler 5 by the cooling branch, and the remaining part of the cooling medium mixed solution is input to the reverse osmosis brine separation device 7 by the feed water pump 6. Through the setting of the cooling branch, a part of the cooling medium mixed solution output by the condenser 3 can be directly input into the cooler 5 for cooling, so as to realize the timely supply of cooling medium.

[0039] Specifically, the pure water in the steam generator 1 is heated and evaporated into water vapor, and enters the steam turbine unit 2 to expand and do work, and the temperature and pressure are reduced, and it becomes a steam-water mixture and enters the condenser 3 for cooling and condensation. At the same time, the water-based absorbent with a higher concentration after being cooled by the cooler 5 enters the condenser 3 and mixes with the steam-water mixture discharged from the steam turbine unit 2, forming a water-based absorbent mixed solution with a lower concentration in the condenser 3, and low-pressure water vapor exists in the condenser 3. After the water-based absorbent mixed solution with lower concentration in the condenser 3 is pressurized by the condensate pump 4, assuming that the total output flow rate is Q, a part of the water-based absorbent mixed solution with lower concentration (flow rate Q2, the proportion of Q is adjustable) enters the cooling branch; the remaining part of the water-based absorbent mixed solution with lower concentration (flow rate Q3) enters the pressurization branch of the feed water pump 6, and enters the reverse osmosis brine separation device 7 after being pressurized by the feed water pump 6. The reverse osmosis brine separation device 7 produces pure water with a flow rate Q1 and enters the steam generator 1. At the same time, the concentrated brine with a flow rate Q4 is produced, which enters the cooling branch after expansion and work by the hydraulic turbine unit 8, and is mixed with the light brine with a flow rate Q2 at the outlet of the condensate pump 4 and enters the cooler 5, and enters the condenser 3 after being cooled by the external environment medium.

[0040] In the specific configuration, the water-based absorbent includes a salt solution. In this embodiment, the water-based absorbent is formed by uniformly dissolving a certain concentration of salt in water, and the salt solution has an absorption characteristic, that is, the saturated vapor pressure is lower than that of pure water at the same temperature. By replacing water with a water-based absorbent, the steam pressure in the condenser 3 can be greatly reduced when the medium temperature in the condenser 3 is constant. At the same time, a reverse osmosis salt water separation device 7 is set in the circulation system, the medium and outlet steam parameters of the steam generator 1 are maintained unchanged, and a hydraulic turbine is set to recover the high-pressure salt water energy, thereby improving the thermal efficiency of the steam power circulation system.

[0041] In some specific embodiments, the solute of the salt solution includes lithium bromide. The lithium bromide aqueous solution has excellent heat absorption performance and can effectively absorb and transfer heat in the system, thereby significantly reducing the steam pressure in the condenser 3 and improving the thermal efficiency of the system.

[0042] In the specific configuration, the condenser 3 includes a spray condenser 3, and the spray device in the spray condenser 3 is connected to the cooling medium output port of the cooler 5. The configuration of the spray condenser 3 enables the lithium bromide aqueous solution to be directly sprayed on the steam, so that the spray cooling medium forms a larger contact area between the steam and the cooling water, thereby improving the heat exchange efficiency, being able to cool and condense the steam more effectively, and reducing the pressure in the condenser 3.

[0043] In a specific embodiment, the cooler 5 includes a shell and tube heat exchanger. In this embodiment, a shell and tube heat exchanger is used, which has a large heat exchange area, can effectively transfer heat, thereby improving the heat exchange efficiency, and has the characteristics of high temperature and high pressure resistance, easy cleaning, and flexible design, so that it can be flexibly adapted during the transformation, reducing the difficulty and cost of transformation.

[0044] Through the description of the above embodiments, the technicians in this field can clearly understand that each embodiment uses a water-based absorbent instead of pure water as the medium of the steam power cycle system. The water-based absorbent can be formed by uniformly dissolving a certain concentration of salt in water. The salt solution has absorption characteristics, that is, the saturated vapor pressure is lower than that of pure water at the same temperature. The condenser 3 adopts a hybrid direct condensation structure, and the concentrated brine is sprayed into the condenser 3, and directly contacts and condenses with the steam discharged from the turbine to form a light brine. After the light brine discharged from the condenser 3 is pressurized, a part of it passes through the reverse osmosis brine separation device 7 to produce concentrated brine and pure water, wherein the pure water enters the steam generator 1 to generate high-temperature steam, and then enters the turbine to expand and work. The concentrated brine is expanded and worked by the hydraulic turbine unit 8 to recover energy and then mixed with another part of the light brine discharged from the condenser 3 to form a concentrated brine, which is sprayed into the condenser 3 after being cooled by the cooler 5. The pressure in the condenser 3 of the whole system is greatly reduced, which can effectively achieve the improvement of thermal efficiency.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A high-efficiency steam power cycle system, characterized in that: include: Steam generators, steam turbine units, condensers, coolers, reverse osmosis brine separation units and hydraulic turbine units; The steam output port of the steam generator is connected to the steam input port of the steam turbine unit, the steam-water mixed output port of the steam turbine unit is connected to the steam-water mixed input port of the condenser, and the cooling medium mixed output port of the condenser is connected to the cooling medium mixed input port of the reverse osmosis brine separation device through a pressurized flow path; and the reverse osmosis brine separation device has a pure water output port and a separation solution output port, and the pure water output port is connected to the pure water input port of the steam generator to form a steam circulation loop; The separation solution outlet is communicated with the medium inlet of the hydraulic turbine unit, the medium outlet of the hydraulic turbine unit is communicated with the cooling medium inlet of the cooler, the cooling medium outlet of the cooler is communicated with the condenser to form a cooling circulation loop, and the cooling medium in the cooling circulation loop is a water-based absorbent; Wherein, the boosting flow path is provided with a boosting pump.

2. The high-efficiency steam power cycle system according to claim 1, characterized in that: The steam turbine unit and the hydraulic turbine unit are both connected to a load.

3. The high-efficiency steam power cycle system according to claim 2, characterized in that: The load includes a drive device or a generator set.

4. The high-efficiency steam power cycle system according to claim 1, characterized in that: A condensate pump and a water feed pump are sequentially arranged on the pressurized flow path along the medium flow direction.

5. The high-efficiency steam power cycle system according to claim 4, characterized in that: A cooling branch is provided between the condensate pump and the feed water pump, one end of the cooling branch is connected to the boost flow path, and the other end of the cooling branch is connected to the cooling medium input port of the cooler, so that a part of the cooling medium output through the condensate pump is transported to the cooler through the cooling branch, and the remaining part of the cooling medium is input into the reverse osmosis brine separation device through the feed water pump.

6. The high-efficiency steam power cycle system according to claim 4, characterized in that: The outlet pressure of the water supply pump is greater than the outlet pressure of the condensate pump.

7. The high-efficiency steam power cycle system according to claim 1, characterized in that: The water-based absorbent includes a saline solution.

8. The high-efficiency steam power cycle system according to claim 7, characterized in that: The solute of the brine solution includes lithium bromide.

9. The high-efficiency steam power cycle system according to claim 1, characterized in that: The condenser comprises a spray condenser, and a spray device in the spray condenser is connected to a cooling medium output port of the cooler.

10. The high-efficiency steam power cycle system according to claim 1, characterized in that: The cooler includes a shell and tube heat exchanger.

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