CN112503392A - Closed circulating water system with self-balancing pressure stabilizing box for flue gas waste heat power generation - Google Patents
Closed circulating water system with self-balancing pressure stabilizing box for flue gas waste heat power generation Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
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- F17D1/00—Pipe-line systems
- F17D1/005—Pipe-line systems for a two-phase gas-liquid flow
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
- F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
- F01K27/00—Plants for converting heat or fluid energy into mechanical energy, not otherwise provided for
- F01K27/02—Plants modified to use their waste heat, other than that of exhaust, e.g. engine-friction heat
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F17—STORING OR DISTRIBUTING GASES OR LIQUIDS
- F17D—PIPE-LINE SYSTEMS; PIPE-LINES
- F17D1/00—Pipe-line systems
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- F17D1/14—Conveying liquids or viscous products by pumping
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Abstract
The invention discloses a closed circulating water system with a self-balancing pressure stabilizing box for flue gas waste heat power generation, and relates to the technical field of industrial waste heat recycling; the closed circulating water system comprises a circulating pump, a heat exchanger I, a pressure stabilizing box and a heat exchanger II which are sequentially connected with the closed loop, the flue gas waste heat utilization loop is connected with the heat exchanger I so that the heat exchanger I can utilize the flue gas waste heat to heat circulating water in the closed circulating water system, and the power generation device loop is connected with the heat exchanger II so that the heat exchanger II can heat a circulating working medium in the power generation device loop; by implementing the technical scheme, the pressure stability of the closed circulating water system under each working condition is realized by utilizing the self-balancing principle of evaporation and condensation of water under the saturated state and by arranging the pressure stabilizing box, the pressure stabilizing requirement of the system under each working condition due to the change of liquid density can be effectively met, and the operation reliability and the economical efficiency of the system are ensured.
Description
Technical Field
The invention relates to the technical field of industrial waste heat recycling, in particular to a closed circulating water system with a self-balancing pressure stabilizing box for flue gas waste heat power generation.
Background
At present, industrial waste heat recycling becomes a heat tide for recycling energy in the industrial field, for example, the waste heat of flue gas can be effectively utilized to generate electricity, the existing flue gas waste heat power generation device mostly adopts an intermediate heat conduction cycle to transfer heat from a heat source system to a power generation system, a heat conduction medium usually adopts heat conduction oil or water, but closed liquid circulation applied by the heat conduction medium generally has cyclic changes of pressure and temperature, especially, the density change of liquid can be directly influenced due to the change of the temperature, and meanwhile, due to the incompressibility of the liquid, when the temperature of the liquid in a closed space rises, the density of the liquid is reduced, the volume of the liquid is increased, the pressure of the system rises suddenly, and the design pressure of the system is rapidly exceeded.
In the existing circulation systems, an accumulator or a high-level open storage tank is mostly adopted for absorbing the volume change of liquid to stabilize the system pressure, but the accumulator or the high-level open storage tank is utilized to stabilize the system pressure, and the following technical defects are respectively existed: wherein
Accumulators are generally of the bladder or piston type: the leather bag type has strict requirements on the working conditions of use, generally requires the medium temperature to be less than 120 ℃, and expensive special products have the tolerance temperature of up to 180 ℃, and are not suitable for high-temperature working conditions; the piston has failure risk due to limited sealing life of the action surface, and also has application limitation in a high-temperature environment;
when a high-level storage tank is adopted, a liquid storage tank is arranged at the highest position of the system elevation, and the system is guaranteed to work effectively under a preset pressure value by utilizing hydrostatic pressure; the upper part of the liquid level of the high-level storage tank is communicated with the atmosphere, and the liquid level of the storage tank can be freely lifted according to the volume change of the liquid in the system, so that the system pressure is stabilized by utilizing constant atmospheric pressure to avoid overpressure; however, when the working pressure of the system is high, the high-level storage tank must be arranged at a high enough height to generate a large enough hydrostatic column pressure to meet the system requirement, so that the arrangement of the storage tank is difficult in engineering application; meanwhile, the working medium is directly contacted with the air, and the risks of corrosion and pollution exist.
Disclosure of Invention
Aiming at the technical problems, the invention aims to provide a closed circulating water system with a self-balancing pressure stabilizing box for power generation by waste heat of flue gas, which aims to solve the application limitation of the conventional pressure stabilizing scheme, utilizes the self-balancing principle of evaporation and condensation of water in a saturated state, realizes the pressure stability of the closed circulating water system under various working conditions by arranging the pressure stabilizing box, and ensures the operation reliability and the economical efficiency of the system.
The technical scheme adopted by the invention is as follows:
a take self-balancing surge tank closed circulation water system for flue gas waste heat power generation includes
The closed circulating water system comprises a circulating pump, a heat exchanger I, a pressure stabilizing box and a heat exchanger II, wherein the circulating pump, the heat exchanger I, the pressure stabilizing box and the heat exchanger II are sequentially connected into a closed loop through pipelines; wherein
The heat exchanger I utilizes the waste heat of the flue gas to heat circulating water in the closed circulating water system;
the pressure stabilizing box provides a buffer space for the volume change of water and is used for stabilizing the pressure of the system;
the heat exchanger II utilizes high-temperature circulating water to heat and evaporate the circulating working medium in the loop of the power generation device;
the circulating pump provides circulating power for the closed circulating water system;
the flue gas waste heat utilization loop is connected with the heat exchanger I and used for recovering flue gas waste heat, so that the heat exchanger I can utilize the flue gas waste heat to heat circulating water in the closed circulating water system;
and the power generation device loop is connected with the power generation device and the heat exchanger II so that the heat exchanger II can heat the circulating working medium in the power generation device loop.
The working principle of the closed circulating water system is as follows: circulating water in the closed circulating water system passes through a heat exchanger I, absorbs heat in a flue gas waste heat utilization loop to be heated, high-temperature circulating water flowing out of the heat exchanger I enters a pressure stabilizing box, steam bubbles carried in liquid high-temperature water or steam subjected to flash evaporation under the action of pressure and temperature effectively realize steam-liquid separation in the pressure stabilizing box, therefore, the upper part of the pressure stabilizing box is steam, the lower part of the pressure stabilizing box is liquid water, a steam-state and liquid-state interface is always maintained in a saturated state, and the liquid water below the steam-liquid interface is always kept at a certain supercooling degree under the action of liquid column static pressure so as to ensure that effective working fluid of the system is liquid circulating water; circulating water is cooled by a circulating working medium in the loop of the power generation device when passing through the heat exchanger II, and then enters the heat exchanger I again after being boosted by the circulating pump, so that a closed circulating loop is formed; from the above, when the temperature of the system rises, the density of circulating water in the system is reduced, the volume is increased, the liquid level height in the pressure stabilizing box rises and compresses the steam space at the upper part, the pressure in the pressure stabilizing box rises, part of steam is condensed into water under the action of the pressure rise, the quality and the volume of the steam are both reduced, the gaseous and liquid working media reach a new balance state at a steam-liquid interface, and the pressure at the liquid level is the saturation pressure corresponding to the current liquid level temperature and is increased compared with the previous state; when the temperature of the system is reduced, contrary to the situation, the liquid level in the pressure stabilizing box is reduced, and the pressure of the system is reduced; according to the technical scheme, closed water circulation is used as middle heat conduction circulation, the self-balancing principle that water is evaporated and condensed in a saturated state is utilized, pressure stability of the closed circulating water system under various working conditions is achieved by arranging the pressure stabilizing box, the system is simple in design but ingenious in design, the system pressure can be guaranteed to operate stably under various working conditions, and the system has good application prospect and economic popularization value.
Preferably, the pressure stabilizing box is arranged at the highest position of the elevation of the closed circulating water system, so that after circulating water is heated in the heat exchanger I and enters the pressure stabilizing box, vapor-liquid separation can be fully realized in the pressure stabilizing box, and liquid column static pressure is formed at the other low positions to ensure that a working medium is kept in a liquid state.
Preferably, the closed circulating water system further comprises a pressure reducing valve arranged on a pipeline of the closed circulating water system, and the pressure reducing valve is used for adjusting the resistance and the flow of the closed circulating water system; preferably, the pressure reducing valve is arranged on a pipeline between the circulating pump and the heat exchanger II, or the pressure reducing valve is arranged on a pipeline between the circulating pump and the heat exchanger I, so that when the closed circulating water system needs to realize the change of the operation flow, the different flow circulating water needed in the closed circulating water system can be adjusted by adjusting the opening of the pressure reducing valve, and the adaptability of the system operation is further ensured.
As another preferred aspect of the above technical solution, the circulation pump is a variable frequency pump, so that when the closed circulation water system needs to change the operation flow, the closed circulation water system can change the flow by changing the operation frequency of the circulation pump.
Preferably, a liquid level monitoring instrument is arranged on the pressure stabilizing box and used for monitoring the liquid level height of the pressure stabilizing box; by adopting the structure, when the liquid level in the pressure stabilizing box is too low, the circulating water can be supplemented in time by sending a signal through the liquid level monitoring instrument, and the running reliability of the system is further ensured.
As the optimization of the technical scheme, the closed circulating water system is also provided with a vacuumizing device for vacuumizing the closed circulating water system. By adopting the structure, equipment and pipelines in the system can be vacuumized before the system is circulated, and the problem that oxygen in the air corrodes the system equipment in the system is avoided.
Preferably, the power generation device loop is provided with a heat exchanger III and a feed pump, the heat exchanger II, the power generation device and the heat exchanger III are sequentially connected through pipelines to form a closed loop, the heat exchanger III is used for cooling exhaust gas discharged by the condensing power generation device, and the feed pump is used for providing pressure for the power generation device to do work and serving as circulating power of the power generation device loop.
Preferably, in the above technical solution, the power generation device is an expander-belt power generation unit; the expander-driven generator set in the technical scheme can be one or a combination of a vortex expander and a generator or a screw expander and a generator or a turbine and a generator.
Preferably, in the above-described embodiment, the heat exchanger III is a condenser or an air cooling island, and is configured to cool and condense exhaust gas discharged from the power generation device by using an input cold source.
As described above, the present invention has at least the following advantages over the prior art:
1. the invention adopts a fully-sealed closed type intermediate circulating water system, utilizes the self-balancing principle of evaporation and condensation of water in a saturated state, realizes the pressure stability of the closed type circulating water system under various working conditions by arranging the pressure stabilizing box, realizes zero loss of water, can effectively solve the application limitation of the existing pressure stabilizing scheme, and ensures the operation reliability and the economical efficiency of the system.
2. Compared with the traditional high-position open storage tank middle circulating system, the invention can effectively avoid the problem of corrosivity of oxygen in the air to system equipment, can effectively prolong the service life of the equipment and the pipeline, and ensures the running reliability of the system under different working conditions; meanwhile, the arrangement difficulty and the construction difficulty of the storage tank can be greatly reduced, and the application limitation of the traditional high-level open storage tank middle circulating system is avoided.
3. Compared with the traditional scheme of using an energy accumulator to stabilize the pressure or using a heat conduction oil open type intermediate circulation system, the invention greatly reduces the construction cost, and the larger the power of the flue gas waste heat power generation device is, the more remarkable the use effect is; particularly, the heat conduction oil has high cost, high operation and maintenance cost, higher waste oil treatment cost after the service life reaches the limit, the use temperature of the heat conduction oil is generally not more than 400 ℃, and the heat conduction oil cannot be used after the heat conduction oil exceeds the upper limit temperature determined by the heat stability of the working medium; the invention utilizes closed water circulation as intermediate heat conduction circulation, can be applied within the temperature range of 100-500 ℃, has environment-friendly working medium, low initial investment and later operation and maintenance cost and good economical usability.
4. The closed circulating water system is mutually isolated from the flue gas waste heat utilization loop and the power generation device loop, namely, the heat source side and the working medium side are effectively isolated, the system adopts water which is cheap and easy to obtain as a circulating medium, the explosion risk is avoided, and particularly, the closed circulating water system is safer and more reliable when alkane is adopted as organic Rankine cycle of the working medium.
In conclusion, the invention can effectively solve the pressure stabilizing requirement generated by the liquid density change in the whole process of starting, stopping and changing working conditions of the system on the premise of meeting the requirement of the working temperature of the system, simplifies the design and control requirements of the system and is safe and reliable; the initial investment cost and the later operation and maintenance cost are effectively reduced, the construction cost is reduced, the application economy can be obviously improved, and the method has good application prospect and popularization and use value.
Drawings
The invention will be described by way of specific embodiments and with reference to the accompanying drawings, in which
Fig. 1 is a schematic flow diagram of a closed circulation water system with a self-balancing surge tank according to an exemplary embodiment of the present invention.
Description of reference numerals: 11-heat exchanger I; 12-heat exchanger II; 13-a circulation pump; 14-a surge tank; 15-a pressure reducing valve; 16-a liquid level monitoring instrument; 21-a power generation device; 22-heat exchanger III; 23-a feed pump; 101-closed circulating water system pipeline; 102-a flue gas waste heat utilization loop; 103-power plant circuit.
Detailed Description
All of the features disclosed in this specification, or all of the steps in any method or process so disclosed, may be combined in any combination, except combinations of features and/or steps that are mutually exclusive.
Any feature disclosed in this specification (including any accompanying claims, abstract) may be replaced by alternative features serving equivalent or similar purposes, unless expressly stated otherwise. That is, unless expressly stated otherwise, each feature is only an example of a generic series of equivalent or similar features.
Example one
This embodiment is substantially as shown in fig. 1: the embodiment provides a closed circulating water system with a self-balancing pressure stabilizing box for power generation by waste heat of flue gas, which comprises a closed circulating water system, a flue gas waste heat utilization loop and a power generation device loop, wherein the closed circulating water system comprises a circulating pump 13, a heat exchanger I11, a pressure stabilizing box 14 and a heat exchanger II12, and the circulating pump 13, the heat exchanger I11, the pressure stabilizing box 14 and the heat exchanger II12 are sequentially connected into a closed loop through a pipeline 101 of the closed circulating water system; the heat exchanger I11 in the closed loop utilizes the flue gas waste heat to heat the circulating water in the closed circulating water system, and then the high-temperature flue gas in the flue gas waste heat utilization loop 102 is cooled; the surge tank 14 provides a buffer space for the volume change of water for stabilizing the system pressure; the heat exchanger II12 heats and evaporates the circulating working medium in the power generation device loop 103 by using high-temperature circulating water in the circulating water system, and the circulating water is cooled at the same time; the circulating pump 13 provides circulating power for the closed circulating water system, so that the circulating water subjected to heat exchange and cooling by the heat exchanger II12 is pressurized again and enters the heat exchanger I11; from the above, the flue gas waste heat utilization loop 102 is connected to the heat exchanger I11 for recovering flue gas waste heat, so that the heat exchanger I11 can utilize the flue gas waste heat to heat the circulating water in the closed circulating water system, the power generation device loop 103 is connected to the power generation device 21 and the heat exchanger II12, so that the heat exchanger II12 can heat the circulating medium in the power generation device loop 103, and it should be noted that the closed circulating water system is isolated from the flue gas waste heat utilization loop 102 and the power generation device loop 103, that is, the heat source side and the working medium side are effectively isolated, and meanwhile, the closed circulating water system uses water as the circulating medium, so that there is no risk of explosion, and especially for organic rankine cycle using alkane as the working medium, reliable operation of the system can be effectively ensured.
As shown in fig. 1, the flue gas waste heat utilization loop 102 includes a high-temperature flue gas pipeline connected to a flue gas inlet of a heat exchanger I11 and a low-temperature flue gas pipeline connected to a flue gas outlet of a heat exchanger I11, and a gas path channel in the heat exchanger I11 is isolated from a closed circulating water system pipeline 101; the power generation device loop 103 is provided with a heat exchanger III22 and a feed pump 23, the heat exchanger II12, the power generation device 21 and the heat exchanger III22 are sequentially connected through pipelines to form a closed loop, that is, the pipeline of the power generation device loop 103 is isolated from the pipeline 101 of the closed circulating water system, in this embodiment, the heat exchanger III22 is used for cooling and condensing exhaust gas discharged by the power generation device 21, and the feed pump 23 is used for providing pressure for the power generation device to do work and serving as circulating power of the power generation device loop.
In this embodiment, the power generation device 21 is an expander-generator set, wherein the expander-generator set may be one or a combination of a scroll expander and a generator, a screw expander and a generator, or a turbine and a generator, or other forms of power generation devices, and can realize that heat is transferred from flue gas to a power generation system to realize power generation in the form of the system of the invention, and the invention is within the protection scope of the invention; meanwhile, the heat exchanger III22 in this embodiment is a condenser or an air cooling island, and is not particularly limited thereto, and all heat exchange devices that can cool and condense the exhaust gas discharged from the power generation device by using an input cold source are also within the protection scope of the present invention.
The pressure stabilizing box 14 provided by the embodiment is arranged at the highest position of the elevation of the closed circulating water system, so that after circulating water is heated in the heat exchanger I11 and enters the pressure stabilizing box, vapor-liquid separation can be fully realized in the pressure stabilizing box, and meanwhile, hydrostatic pressure is formed at other low positions to ensure that a working medium is kept in a liquid state; compared with the traditional high-level open storage tank intermediate circulation system, the closed circulation system is adopted in the embodiment, so that the problem of corrosivity of oxygen in air to system equipment can be effectively avoided, the service lives of the equipment and the pipeline can be effectively prolonged, and the running stability of the system under different working conditions is ensured; meanwhile, the arrangement difficulty and the construction difficulty of the storage tank can be greatly reduced, and the application limitation of the traditional high-level open storage tank middle circulating system is avoided.
Preferably, the pressure stabilizing tank 14 provided by the embodiment is provided with a liquid level monitoring instrument 16 for monitoring the liquid level height of the pressure stabilizing tank 14, and when the liquid level in the pressure stabilizing tank 14 is too low, the liquid level monitoring instrument 16 can send a signal to replenish circulating water in time, so that the reliability of the operation of the system is ensured.
The circulating pump 13 that this embodiment provided is preferably the frequency conversion circulating pump, and when this closed circulating water system need realize the change of operation flow like this, can realize the purpose of changing the flow of closed circulating water system pipeline through the operating frequency who changes circulating pump 13.
Compared with the traditional scheme of using an energy accumulator to stabilize the pressure or using a heat conduction oil open type intermediate circulation system, the scheme of the invention has the advantages that the engineering cost is greatly reduced, and the higher the power of the flue gas waste heat power generation device 21 is, the more remarkable the use effect is; particularly, the heat conduction oil has high cost, high operation and maintenance cost, higher waste oil treatment cost after the service life reaches the limit, the use temperature of the heat conduction oil is generally not more than 400 ℃, and the heat conduction oil cannot be used after the heat conduction oil exceeds the upper limit temperature determined by the heat stability of the working medium; in the embodiment, closed water circulation is used as intermediate heat conduction circulation, the heat conduction circulation is applicable within the temperature range of 100-500 ℃, and the working medium is environment-friendly, low in initial investment and later operation and maintenance cost and good in economical usability.
The closed circulating water system has the following specific implementation modes:
gradually injecting circulating water into the intermediate circulating water system until the height of the water level in the pressure stabilizing tank 14 reaches a preset value;
starting a system circulating pump 13 to establish circulation of water in a closed system;
the heat exchanger I11 and the heat exchanger II12 are put into operation, circulating water is heated in the heat exchanger I11 and reaches the highest working temperature of a circulating water system at the outlet of the heat exchanger I11, the circulating water flows through the pressure stabilizing box 14 and then enters the heat exchanger II12, and the circulating water is cooled by the heat exchanger II12 to form the circulating change of the system temperature;
the heat input to the heat exchanger I11 through the flue gas waste heat utilization loop 102 is gradually increased, the temperature of the circulating water is stably increased, when the water temperature in the pressure stabilizing box 14 reaches the saturation temperature under the current pressure, the circulating water starts to evaporate, the space above the water level in the pressure stabilizing box 14 is filled with water vapor, and the pressure in the pressure stabilizing box 14 is gradually increased under the action of the water vapor;
along with the rising of the water temperature at the outlet of the circulating water pipeline of the heat exchanger I11, the steam in the upper space of the pressure stabilizing box 14 is increased, the pressure of the closed circulating water system is gradually increased, and simultaneously the density and the volume of water are reduced and increased, so that the water level in the pressure stabilizing box 14 is also increased until the water temperature at the outlet of the heat exchanger I11 reaches a preset value, and at the moment, the pressure and the water level in the pressure stabilizing box 14 tend to be stable;
changing the running frequency of the circulating pump 13 to set the system flow to a target value;
from the above, when the working temperature changes in the closed circulating water system, the system pressure changes therewith, and the saturated state of the dynamic balance of steam and water is always maintained at the liquid level in the pressure stabilizing box 14 by utilizing the self-balancing principle that water is evaporated and condensed in the saturated state, so that the operation reliability and the economical efficiency of the system are ensured.
According to the above, the working pressure of the closed circulating water system depends on the working temperature of the system, and when the saturation pressure corresponding to the working temperature of the system meets the requirement of the system on the working pressure, the invention can effectively solve the pressure stabilization requirement of the system caused by the change of the liquid density in the whole process of starting, stopping and changing the working condition, simultaneously simplifies the design and control requirements of the system, reduces the construction cost, and has reliable economical practicability.
Example two
The second embodiment is substantially the same as the first embodiment, except that: when the closed circulating water system of the embodiment needs to realize the change of the operation flow, the adopted circulating pump does not select a variable frequency pump, but a pressure reducing valve is arranged on a pipeline of the closed circulating water system, and the resistance and the flow of the closed circulating water system are adjusted by the pressure reducing valve; as a preference of this embodiment, the pressure reducing valve may be disposed on the pipeline between the circulating pump and the heat exchanger II, or the pressure reducing valve may be disposed on the pipeline between the circulating pump and the heat exchanger I, that is, the circulating water with different flow rates required in the closed circulating water system can be adjusted by adjusting the opening degree of the pressure reducing valve 15.
The closed circulating water system has the following specific implementation modes:
gradually injecting circulating water into the intermediate circulating water system until the height of the water level in the pressure stabilizing tank 14 reaches a preset value;
starting a system circulating pump 13 to establish circulation of water in a closed system;
the heat exchanger I11 and the heat exchanger II12 are put into operation, circulating water is heated in the heat exchanger I11 and reaches the highest working temperature of a circulating water system at the outlet of the heat exchanger I11, the circulating water flows through the pressure stabilizing box 14 and then enters the heat exchanger II12, and the circulating water is cooled by the heat exchanger II12 to form the circulating change of the system temperature;
the heat input to the heat exchanger I11 through the flue gas waste heat utilization loop 102 is gradually increased, the temperature of the circulating water is stably increased, when the water temperature in the pressure stabilizing box 14 reaches the saturation temperature under the current pressure, the circulating water starts to evaporate, the space above the water level in the pressure stabilizing box 14 is filled with water vapor, and the pressure in the pressure stabilizing box 14 is gradually increased under the action of the water vapor;
along with the rising of the water temperature at the outlet of the circulating water pipeline of the heat exchanger I11, the steam in the upper space of the pressure stabilizing box 14 is increased, the pressure of the closed circulating water system is gradually increased, and simultaneously the density and the volume of water are reduced and increased, so that the water level in the pressure stabilizing box 14 is also increased until the water temperature at the outlet of the heat exchanger I11 reaches a preset value, and at the moment, the pressure and the water level in the pressure stabilizing box 14 tend to be stable;
adjusting the opening of the pressure reducing valve 15 to set the system flow to a target value;
from the above, when the working temperature changes in the closed circulating water system, the system pressure changes therewith, and the saturated state of the dynamic balance of steam and water is always maintained at the liquid level in the pressure stabilizing box 14 by utilizing the self-balancing principle that water is evaporated and condensed in the saturated state, so that the operation reliability and the economical efficiency of the system are ensured.
This embodiment utilizes the relief pressure valve to adjust closed circulating water system resistance and flow, for the flow that utilizes the frequency conversion circulating pump to change closed circulating water system pipeline, adjusts more convenient and accurate, can further guarantee the adaptability of system operation.
EXAMPLE III
The third embodiment is substantially the same as the second embodiment, except that: the embodiment provides a closed circulating water system with a self-balancing pressure stabilizing box for power generation by waste heat of flue gas, and on the basis of the first embodiment, the closed circulating water system is also provided with a vacuumizing device (not shown in the figure) for vacuumizing the closed circulating water system; it is worth noting that if the pressure stabilizing box is not vacuumized before water is poured into the water, the top of the pressure stabilizing box needs to be communicated with the atmosphere during water pouring so that air can be smoothly discharged during water pouring, and the pressure stabilizing box is closed after water pouring is completed to form a closed circulating water system.
The closed circulating water system has the following specific implementation modes:
vacuumizing the closed circulating water system by using a vacuumizing device, so that all equipment and pipelines of the system are in a vacuum state before circulating water is filled;
then, gradually injecting the circulating water into the fully-sealed closed type intermediate circulating water system until the height of the water level in the pressure stabilizing box 14 reaches a preset value, and at the moment, the upper part of the water level of the pressure stabilizing box 14 is in a vacuum state;
starting a system circulating pump 13 to establish circulation of water in a closed system;
the heat exchanger I11 and the heat exchanger II12 are put into operation, circulating water is heated in the heat exchanger I11 and reaches the highest working temperature of a circulating water system at the outlet of the heat exchanger I11, the circulating water flows through the pressure stabilizing box 14 and then enters the heat exchanger II12, and the circulating water is cooled by the heat exchanger II12 to form the circulating change of the system temperature;
the heat input to the heat exchanger I11 through the flue gas waste heat utilization loop 102 is gradually increased, the temperature of the circulating water is stably increased, when the water temperature in the pressure stabilizing box 14 reaches the saturation temperature under the current pressure, the circulating water starts to evaporate, the space above the water level in the pressure stabilizing box 14 is filled with water vapor, and the pressure in the pressure stabilizing box 14 is gradually increased under the action of the water vapor;
along with the rising of the water temperature at the outlet of the circulating water pipeline of the heat exchanger I11, the steam in the upper space of the pressure stabilizing box 14 is increased, the pressure of the closed circulating water system is gradually increased, and simultaneously the density and the volume of water are reduced and increased, so that the water level in the pressure stabilizing box 14 is also increased until the water temperature at the outlet of the heat exchanger I11 reaches a preset value, and at the moment, the pressure and the water level in the pressure stabilizing box 14 tend to be stable;
adjusting the opening of the reducing valve 15 to set the system flow to a target value;
and similarly, when the working temperature in the closed circulating water system changes, the system pressure changes along with the change, and the saturated state of the dynamic balance of the steam and the water is always maintained at the liquid level in the pressure stabilizing box 14 by utilizing the self-balancing principle of evaporation and condensation of the water in the saturated state.
This embodiment adopts closed circulating water system still to dispose evacuating device, can effectively avoid oxygen in the air to the corrosivity problem of system's equipment, can effectively prolong the life of equipment and pipeline, guarantees the system operating stability under different operating modes, and its application effect is more obvious than embodiment one and embodiment two.
In conclusion, the closed type intermediate circulating water system adopts a fully sealed closed type intermediate circulating water system, utilizes the self-balancing principle of evaporation and condensation of water in a saturated state, realizes pressure stability of the closed type intermediate circulating water system under various working conditions by arranging the pressure stabilizing box, realizes zero loss of water, can effectively solve application limitations of the existing pressure stabilizing scheme, ensures the operation reliability and the economical efficiency of the system, particularly has good application prospect and popularization and use value in the closed type liquid circulating system applied in the industrial field, and is suitable for popularization and use.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents and improvements made within the spirit and principle of the present invention are intended to be included within the scope of the present invention.
Claims (10)
1. A take self-balancing surge tank closed circulating water system for flue gas waste heat power generation, its characterized in that: the system comprises a closed circulating water system, wherein the closed circulating water system comprises a circulating pump, a heat exchanger I, a pressure stabilizing box and a heat exchanger II, and the circulating pump, the heat exchanger I, the pressure stabilizing box and the heat exchanger II are sequentially connected into a closed loop through pipelines;
the flue gas waste heat utilization loop is used for recovering flue gas waste heat and is connected with the heat exchanger I, so that the heat exchanger I can utilize the flue gas waste heat to heat circulating water in the closed circulating water system;
and the power generation device loop is connected with the power generation device and the heat exchanger II so that the heat exchanger II can heat the circulating working medium in the power generation device loop.
2. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 1, is characterized in that: the pressure stabilizing box is arranged at the highest position of the elevation of the closed circulating water system, so that circulating water enters the pressure stabilizing box after being heated in the heat exchanger I, and vapor-liquid separation can be fully realized in the pressure stabilizing box.
3. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 1, is characterized in that: the closed circulating water system is characterized by further comprising a pressure reducing valve arranged on a pipeline of the closed circulating water system, and the pressure reducing valve is used for adjusting resistance and flow of the closed circulating water system.
4. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation as claimed in claim 3, is characterized in that: the pressure reducing valve is arranged on a pipeline between the circulating pump and the heat exchanger II, or the pressure reducing valve is arranged on a pipeline between the circulating pump and the heat exchanger I.
5. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 1, is characterized in that: the circulating pump is a variable frequency pump, so that the flow of the closed circulating water system pipeline can be changed by changing the operating frequency of the circulating pump.
6. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 1, is characterized in that: and a liquid level monitoring instrument is arranged on the pressure stabilizing box and used for monitoring the liquid level height of the pressure stabilizing box.
7. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 1, is characterized in that: the closed circulating water system is also provided with a vacuumizing device for vacuumizing the closed circulating water system.
8. The closed circulating water system with the self-balancing pressure stabilizing tank for power generation by waste heat of flue gas as claimed in any one of claims 1 to 7, wherein: the heat exchanger II, the power generation device and the heat exchanger III are sequentially connected through pipelines to form a closed loop, the heat exchanger III is used for cooling and condensing exhaust gas discharged by the power generation device, and the feed pump is used for providing pressure for the power generation device to do work and serving as circulating power of the power generation device loop.
9. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 8, is characterized in that: the power generation device is an expander with a generator set.
10. The closed circulating water system with the self-balancing pressure stabilizing box for the flue gas waste heat power generation according to claim 8, is characterized in that: and the heat exchanger III is a condenser or an air cooling island.
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| CN202011144555.5A CN112503392A (en) | 2020-10-23 | 2020-10-23 | Closed circulating water system with self-balancing pressure stabilizing box for flue gas waste heat power generation |
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| CN202011144555.5A CN112503392A (en) | 2020-10-23 | 2020-10-23 | Closed circulating water system with self-balancing pressure stabilizing box for flue gas waste heat power generation |
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| CN112503392A true CN112503392A (en) | 2021-03-16 |
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| CA1323546C (en) * | 1987-05-05 | 1993-10-26 | Anton Schwarz | System for absorbing the expansion in liquid circulating systems |
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Application publication date: 20210316 |