Efficient steam power circulating device

Abstract

The invention relates to the technical field of circulating power machinery, and provides an efficient steam power circulating device which comprises a steam generator, a turboset, a condenser, a cooler and a membrane distillation saline water separation device. 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 condenser is connected with the membrane distillation saline water separation device, the membrane distillation saline water separation device is provided with a pure water output port and a separation solution output port, and the pure water output port is communicated with a pure water input port of the steam generator; the separated solution output port is communicated with the cooler, and the cooling medium is a water-based absorbent; the first pressurizing flow path and the second pressurizing flow path are each 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, and the heat efficiency of the circulation system is improved.

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 device. 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 the related technologies, 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. It is difficult to increase and is not conducive to the transformation of the existing system. The lowest pressure of the circulation system is located in the condenser. Since the medium discharged from the turbine into the condenser is saturated steam, the lowest pressure is directly related to the lowest temperature. Therefore, reducing the medium pressure means reducing the temperature, which also makes it difficult to implement. It is also 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 device, which is used to solve the defects in 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 device, comprising: a steam generator, a steam turbine unit, a condenser, a cooler and a membrane distillation salt water separation device; 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 membrane distillation salt water separation device through a first boosting flow path; and the membrane distillation salt water 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 through a second boosting flow path to form a steam circulation loop; the separation solution output port is connected to the cooling medium input port of the cooler, and 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 first boosting flow path and the second boosting flow path are both provided with a boosting pump.

[0006] According to the high-efficiency steam power cycle device provided by the present invention, the output end of the steam turbine unit is connected to a load.

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

[0008] According to the high-efficiency steam power cycle device provided by the present invention, a cooling branch is provided on the first boost flow path, one end of the cooling branch is connected to the first boost flow path, and the other end of the cooling branch is connected to the input port of the cooler, so that a part of the cooling medium is transported to the cooler by the cooling branch, and the remaining part of the cooling medium is input into the membrane distillation brine separation device.

[0009] According to the high-efficiency steam power cycle device provided by the present invention, the boost pump on the first boost flow path is located upstream of the connection position of the cooling branch, and the separation solution outlet is connected to the cooling branch.

[0010] According to the high-efficiency steam power cycle device provided by the present invention, the outlet pressure of the boosting pump in the second boosting flow path is greater than the outlet pressure of the boosting pump in the first boosting flow path.

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

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

[0013] According to the high-efficiency steam power cycle device 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 device provided by the present invention, the cooler includes a shell and tube heat exchanger.

[0015] The invention provides a high-efficiency steam power cycle device, which replaces the cooling medium in the cooling cycle with a water-based absorbent, so that under the condition of a certain ambient cold source temperature, the saturated steam pressure in the condenser can be greatly reduced, the turbine output can be improved, and the thermal efficiency of the cycle system can be increased. Moreover, by changing the cooling medium, it is possible to improve the existing equipment and reduce the difficulty and cost of transformation. 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 creative work.

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

[0018] Reference numerals: 1. Steam generator; 2. Steam turbine unit; 3. Condenser; 4. Condensate pump; 5. Cooler; 6. Membrane distillation brine separation device; 7. Feed water pump. 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 main ways to improve the thermal efficiency of the system: increasing the maximum temperature of the circulation system or reducing the minimum pressure of the circulation system. It is difficult to increase the upper limit of the maximum temperature of the circulation system, and it is also difficult to improve the existing 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 device includes a steam generator 1, a turbine unit 2, a condenser 3, a cooler 5 and a membrane distillation brine separation device 6; the steam output port of the steam generator 1 is connected to the steam input port of the turbine unit 2, the steam-water mixed output port of the turbine unit 2 is connected to the steam-water mixed input port of the condenser 3, and the cooling medium mixed output port of the condenser 3 is connected to the cooling medium mixed input port of the membrane distillation brine separation device 6 through a first boosting flow path; and the membrane distillation brine separation device 6 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 through a second boosting flow path to form a steam circulation loop; the separation solution output port is connected to the cooling medium input port of the cooler 5, and 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 first boosting flow path and the second boosting flow path are both provided with a boosting pump. When the thermal efficiency of the system is improved by lowering the minimum pressure of the circulation system, the main purpose is to reduce the pressure in the condenser 3. In this embodiment, the cooling medium is replaced by a water-based absorbent, which has absorption characteristics so that 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 membrane distillation brine separation device 6 are connected end to end through pipelines to form a steam circulation loop, and the steam thermal energy is utilized 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 membrane distillation salt water separation device 6, thereby realizing the communication between the upstream and downstream. The steam output port of the steam generator 1 is connected to the steam input port of the steam turbine unit 2 through a pipeline, realizing the communication between the upstream and downstream in the steam flow circulation loop.

[0029] The cooler 5, the condenser 3 and the membrane distillation brine separation device 6 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 membrane distillation brine separation device 6 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 require 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 membrane distillation brine separation device 6. This greatly reduces the difficulty of improving the existing system and reduces the cost of modification.

[0031] The membrane distillation salt water separation device 6 is also provided with a cooling system, through which the water vapor can be cooled so that the water vapor is condensed into fresh water. That is, the membrane distillation salt water separation device 6 can separate pure water (fresh water) and other dissolved substances to achieve the separation of pure water.

[0032] According to some embodiments provided by the present invention, a load is connected to the output end of the steam turbine unit 2. 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 load to the steam turbine unit 2, efficient energy conversion is realized, and the energy conversion rate of the system is improved.

[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 cooling branch is provided on the first pressurized flow path, one end of the cooling branch is connected to the first pressurized 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 is transported to the cooler 5 by the cooling branch, and the remaining part of the cooling medium is input into the membrane distillation brine separation device 6.

[0035] Specifically, a condensate pump 4 is provided on the first pressurized flow path, a water supply pump 7 is provided on the second pressurized flow path, and a membrane distillation salt water separation device 6 is provided between the first pressurized flow path and the second pressurized flow path. This arrangement is beneficial to the circulation of steam in the overall system and the flow of the cooling circulation loop.

[0036] Specifically, after the steam turbine unit 2 performs work, the high-temperature and high-pressure steam will form a low-temperature and low-pressure steam-water mixture, which can be cooled by contacting with the cooling medium in the condenser 3, causing part of the steam 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. It is necessary to increase its pressure through the condensate pump 4, and the pure water separated and treated by the membrane distillation brine separation device 6 can be continuously and timely output through the water feed pump 7, so as to achieve high-efficiency circulation of the entire circulation system.

[0037] In the specific setting, the boost pump on the first boost flow path is located upstream of the cooling branch connection position, and the separation solution outlet is connected to the cooling branch. 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.

[0038] 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 (the booster pump on the first booster flow path), 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 membrane distillation brine separation device 6, and after separation by the membrane distillation brine separation device 6, pure water with a flow rate Q1 is generated and pressurized by the water feed pump 7 and enters the steam generator 1, and at the same time, concentrated brine with a flow rate Q4 is generated and enters the cooling branch, and is mixed with the dilute 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.

[0039] In some embodiments, the outlet pressure of the booster pump in the second booster flow path is greater than the outlet pressure of the booster pump in the first booster flow path. That is, after the cooling medium mixed solution is pressurized by the condensate pump 4, a part of it enters the cooler 5 through the cooling branch, and the remaining part enters the membrane distillation salt water separation device 6, and the separation of pure water and medium solution is achieved through the membrane distillation salt water separation device 6. And by arranging a water supply pump 7 downstream of the membrane distillation salt water separation device 6, it is beneficial to timely transport the fresh water separated in the membrane distillation salt water separation device 6 to increase the circulation rate of the steam circulation loop.

[0040] It is understandable that the membrane distillation salt water separation device 6 needs to rely on the temperature difference to realize the condensation of water vapor, thereby realizing the separation of fresh water and the cooling medium dissolved solution. That is, the salt water evaporates after heating on one side of the membrane, and the water vapor migrates to the low temperature side through the membrane and condenses on the low temperature side to form fresh water. In this embodiment, the fresh water on the low temperature side can be delivered to the steam generator 1 in time through the setting of the water feed pump 7, thereby increasing the circulation rate of the entire system.

[0041] 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 membrane distillation salt water separation device 6 is set in the circulation system, which can achieve the separation of pure water, thereby maintaining the steam circulation in the entire system.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] 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 an absorption characteristic, 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 membrane distillation brine separation device 6 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 do work, and the concentrated brine enters the cooler 5 through the cooling branch to form 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.

[0046] 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 device, characterized in that: include: Steam generator, steam turbine unit, condenser, cooler and membrane distillation brine separation unit; The steam output port of the steam generator is communicated with the steam input port of the steam turbine unit, the steam-water mixed output port of the steam turbine unit is communicated with the steam-water mixed input port of the condenser, the cooling medium mixed output port of the condenser is communicated with the cooling medium mixed input port of the membrane distillation salt water separation device through a first pressurized flow path; and the membrane distillation salt water separation device has a pure water output port and a separation solution output port, and the pure water output port is communicated with the pure water input port of the steam generator through a second pressurized flow path to form a steam circulation loop; The separation solution outlet is communicated with the cooling medium inlet of the cooler, and the cooling medium outlet of the cooler is communicated with the condenser to form a cooling circulation loop, wherein the cooling medium in the cooling circulation loop is a water-based absorbent; Wherein, both the first boosting flow path and the second boosting flow path are provided with a boosting pump.

2. The high-efficiency steam power cycle device according to claim 1, characterized in that: A load is connected to the output end of the steam turbine unit.

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

4. The high-efficiency steam power cycle device according to claim 1, characterized in that: A cooling branch is provided on the first pressurized flow path, one end of the cooling branch is connected to the first pressurized flow path, and the other end of the cooling branch is connected to the input port of the cooler, so that a part of the cooling medium is transported to the cooler by the cooling branch, and the remaining part of the cooling medium is input into the membrane distillation brine separation device.

5. The high-efficiency steam power cycle device according to claim 4, characterized in that: The booster pump on the first booster flow path is located upstream of the connection position of the cooling branch, and the separation solution outlet is connected to the cooling branch.

6. The high-efficiency steam power cycle device according to claim 4, characterized in that: An outlet pressure of the boost pump in the second boost flow path is greater than an outlet pressure of the boost pump in the first boost flow path.

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

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

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

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