Novel photo-thermal and photoelectric sea water desalination system for sea island

Abstract

The utility model discloses a novel photo-thermal and photoelectric sea water desalination system for an island, which comprises a steam generating and heating evaporation system, a circulating cooling and material water system, a finished product water system, a strong brine system and a vacuum system, and is characterized in that the steam generating and heating evaporation system comprises a solar thermal collector, and the lower part of the solar thermal collector is connected with a lower header; the upper part of the solar heat collector is connected with a steam-water separator, a steam outlet of the steam-water separator is connected with a first-effect evaporator of an evaporator, and a last-effect evaporator of the evaporator is connected with a condenser; the circulating cooling and material water system comprises a seawater pipeline, a material water pipeline is connected in the seawater pipeline on the downstream side of the condenser, a saline water heater is arranged on the material water pipeline, and the material water pipeline is connected with a material water spraying device of each effect evaporator in the evaporators; the scheme utilizes the heat of solar energy to carry out seawater desalination, and has the characteristics of easy acquisition of a heat source, low operating temperature, complex technology and simple operation.

Description

Technical Field

[0001] The utility model belongs to the technical field of seawater desalination, and particularly relates to a new type of island photo-thermal and photovoltaic seawater desalination system. Background Art

[0002] Low-temperature multi-effect and multi-stage flash technologies are commonly used in thermal seawater desalination. Since the capacity of general equipment is relatively small, simply adopting the low-temperature multi-effect process, the concentration ratio of material water will be relatively low, affecting the thermal efficiency. If the brine recycling method is adopted, the boiling point elevation value of each effect will be increased, which is unfavorable for heat exchange. Especially for isolated islands lacking power and heat as energy support, the existing seawater desalination technologies are difficult to meet the engineering and usage requirements. Content of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a new type of island photo-thermal and photovoltaic seawater desalination system, which solves the problems of low efficiency and low fresh water output in the existing scheme, and uses solar energy for seawater desalination, and can better meet the seawater desalination requirements of islands.

[0004] According to the technical solution of the utility model, the utility model provides a new type of island photo-thermal and photovoltaic seawater desalination system, which includes a steam generation and heating evaporation system, a circulating cooling and material water system, a finished water system, a concentrated brine system, and a vacuum system. Among them:

[0005] The steam generation and heating evaporation system includes an inclined solar collector. A lower header is connected to the lower part of the solar collector, and a steam-water separator is connected to the upper part of the solar collector. The steam-water separator is connected to the lower header through a downcomer; it also includes an evaporator, and the evaporator is a multi-effect evaporator. The steam discharge port of the steam-water separator is connected to the first-effect evaporator of the evaporator, and the last-effect evaporator of the evaporator is connected to a condenser;

[0006] The circulating cooling and material water system includes a seawater pipeline. The condenser is located on the seawater pipeline. A seawater booster pump is arranged on the seawater pipeline. A material water pipeline is connected to the seawater pipeline. The seawater booster pump is connected to the condenser through the seawater pipeline. The condenser is connected to a brine heater through the seawater pipeline and the material water pipeline. The material water pipeline is connected to the material water spraying devices of each effect evaporator in the evaporator;

[0007] The finished water system includes a finished water pipeline. The finished water discharge port of the last-effect evaporator of the evaporator is connected to the condenser. The condenser is connected to the finished water pipeline. A finished water pump is arranged in the finished water pipeline;

[0008] The brine system includes a primary brine pipeline and a secondary brine pipeline; the primary brine discharge port of the last-effect evaporator of the evaporator is connected to the brine heater through the primary brine pipeline, and a primary brine discharge pump is provided in the primary brine pipeline; the secondary brine discharge port of the last-effect evaporator of the evaporator is connected to the secondary brine pipeline, the brine heater is located on the secondary brine pipeline, and a secondary brine discharge pump is also provided in the secondary brine pipeline;

[0009] The vacuum system includes a vacuum pipeline, the condenser is connected to the vacuum pipeline, and a vacuum pump is provided in the vacuum pipeline.

[0010] Furthermore, the steam-water separator has an overflow port, and the overflow port is connected to the first-effect evaporator of the evaporator.

[0011] Furthermore, each effect evaporator of the evaporator has a brine flash tank, the overflow port of the steam-water separator is connected to the brine flash tank of the first-effect evaporator, and the brine flash tanks of each effect evaporator are connected in sequence.

[0012] Furthermore, the secondary brine discharge port is located in the brine flash tank of the last-effect evaporator.

[0013] Furthermore, a brine makeup pipeline is connected to the primary brine pipeline, and the other end of the brine makeup pipeline is connected to the downcomer or the lower header.

[0014] Furthermore, the multi-effect evaporators of the evaporator are divided into several groups, each effect evaporator of each group is connected with a non-condensable gas discharge pipeline, and the non-condensable gas discharge pipeline is connected to the condenser.

[0015] Compared with the prior art, the beneficial technical effects of the present utility model are as follows:

[0016] The novel island solar thermal and photovoltaic seawater desalination system of the present utility model proposes the concept of combining two process methods of low-temperature multi-effect and multi-stage flash evaporation to improve the overall thermal efficiency, and uses the heat of solar energy for seawater desalination; the combined process method of low-temperature multi-effect and multi-stage flash evaporation can relatively increase the concentration ratio, does not affect the boiling point elevation value of the low-temperature multi-effect part, and at the same time slightly increases the fresh water output through the primary stage-by-stage flash evaporation of the concentrated brine; this solution has the characteristics of easy access to heat sources, low operating temperature, complex technology but simple operation. Description of the Drawings

[0017] Figure 1 is a structural schematic diagram according to an embodiment of the present utility model.

[0018] Explanation of the reference numerals in the drawings:

[0019] 1. Evaporator; 2. Condenser; 3. Solar collector; 4. Lower header; 5. Steam-water separator; 6. Vacuum pump; 7. Seawater booster pump; 8. Primary brine discharge pump; 9. Secondary brine discharge pump; 10. Product water pump; 11. Brine heater; 12. Downcomer; 13. Seawater pipeline; 14. Material water pipeline; 15. Material water spray device; 16. Product water pipeline; 17. Primary brine pipeline; 18. Secondary brine pipeline; 19. Vacuum pipeline; 20. Brine make-up pipeline; 21. Brine flash tank. Detailed implementation manners

[0020] The present utility model provides a novel island solar-thermal and photovoltaic seawater desalination system, especially for areas such as isolated islands lacking power and heat as energy supports, to solve the problems of low efficiency and low fresh water production in existing solutions, and utilize solar energy for seawater desalination, which can better meet the seawater desalination needs of islands.

[0021] Please refer to Figure 1 , a novel island solar-thermal and photovoltaic seawater desalination system according to an embodiment of the present utility model mainly consists of a steam generation and heating evaporation system, a circulating cooling and material water system, a product water system, a concentrated brine system, and a vacuum system. The above systems mainly include an evaporator 1, a condenser 2, a solar collector 3, a lower header 4, a steam-water separator 5, a vacuum pump 6, a seawater booster pump 7, a primary brine discharge pump 8, a secondary brine discharge pump 9, a product water pump 10, and a brine heater 11.

[0022] The steam generation and heating evaporation system mainly consists of a solar heat collection steam generation system, a multi-effect evaporation system, and a final effect condensing system; among which, there is a solar collector 3 arranged obliquely, a lower header 4 is connected to the lower part of the solar collector 3, a steam-water separator 5 is connected to the upper part of the solar collector 3, and the steam-water separator 5 is connected to the lower header 4 through a downcomer 12; specifically, the solar collector 3, the lower header 4, and the steam-water separator 5 are connected through internal pipes of the equipment, and the solar collector 3, the lower header 4, the steam-water separator 5, and the internal pipes of the equipment contain brine (seawater) to be evaporated. There is also an evaporator 1, and the evaporator 1 is a multi-effect evaporator. Each effect in the multi-effect evaporator is connected in sequence. The steam discharge port of the steam-water separator 5 is connected to the steam inlet of the first effect evaporator of the evaporator 1. The steam inlet of the first effect evaporator is connected to the steam pipeline inside the first effect evaporator. The steam pipeline is cooled by a material water spraying device 15 so that the steam therein condenses into condensate and enters the condensate tank on the downstream side of the first effect evaporator. The basic structures of each effect evaporator are the same, and the condensate tanks are connected in sequence through pipelines. Each effect evaporator is connected through a gas transmission pipeline to gradually convey steam. The multi-effect evaporator preferably has at least three, that is, a first effect evaporator, a second effect evaporator, and a third effect evaporator. The final effect evaporator of the evaporator 1 is connected to the condenser 2 through a pipeline to convey gas, and the gas includes water vapor and non-condensable gas (abbreviated as non-condensable gas).

[0023] When the steam generation and heating evaporation system works, the solar collector 3 heats the brine to generate steam. The steam-water mixture enters the steam-water separator 5 at the upper part of the solar collector 3. The steam and water are separated in the steam-water separator 5. After the steam is demisted by the demisting device at the upper part of the steam-water separator 5, it enters the first effect of the evaporator 1 as heating steam; the remaining brine enters the lower header 4 of the solar collector 3 from the downcomer 12 for another solar heating process. Further, brine is replenished into the downcomer 12 or the lower header 4; the steam-water separator 5 has an overflow port at a suitable position, such as in the middle. The overflow port is connected to the first effect evaporator of the evaporator 1 through an overflow pipeline. The concentrated brine overflows into the first effect of the evaporator 1 through this overflow pipeline, is heated step by step, and finally discharged to the condenser 2.

[0024] The circulating cooling and material water system includes a seawater pipeline 13. The condenser 2 is located on the seawater pipeline 13. A seawater booster pump 7 is arranged in the seawater pipeline 13. A material water pipeline 14 is connected in the seawater pipeline 13. A brine heater 11 is arranged on the material water pipeline 14. The seawater booster pump 7 is connected to the condenser 2 through the seawater pipeline 13. The condenser 2 is connected to the brine heater 11 through the seawater pipeline 13 and the material water pipeline 14. The material water pipeline 14 is connected to the material water spraying devices 15 of each effect evaporator in the evaporator 1.

[0025] When the circulating cooling and material water system is working, seawater is used as the circulating cooling water of the last-effect condenser 2 to condense the gas in the condenser 2. A part of the seawater in the seawater pipeline 13 after heat exchange in the condenser 2 is discharged into the material water pipeline 14 and used as the material water source of the low-temperature multi-effect evaporator 1 for spraying. Further, the material water first recovers part of the heat by using the brine discharged from the last effect (through the brine heater 11) to increase the temperature of the material water, and then is supplied to the material water spray of each effect.

[0026] The finished water system includes a finished water pipeline 16. The finished water discharge port (at the condensate tank) of the last-effect evaporator of the evaporator 1 is connected to the condenser 2, the condenser 2 is connected to the finished water pipeline 16, and a finished water pump 10 is provided in the finished water pipeline 16. The finished water pipeline 16 supplies the finished water externally.

[0027] The finished water (or product water) refers to the fresh water generated by the evaporation of seawater. The seawater is gradually drained to the last effect and the condensate of the condenser 2 is collected and then discharged from the system under the pressure of the finished water pump 10.

[0028] The concentrated brine system includes a primary brine pipeline 17 and a secondary brine pipeline 18. The primary brine discharge port of the last-effect evaporator of the evaporator 1 is connected to the brine heater 11 through the primary brine pipeline 17, and a primary brine discharge pump 8 is provided in the primary brine pipeline 17. The secondary brine discharge port of the last-effect evaporator of the evaporator 1 is connected to the secondary brine pipeline 18. The brine heater 11 is located on the secondary brine pipeline 18, and a secondary brine discharge pump 9 is also provided in the secondary brine pipeline 18.

[0029] The concentrated brine system is used to collect the seawater (concentrated brine) evaporated and concentrated in each effect evaporator and discharge them together; in other words, the evaporator 1 is connected to the brine heater 11 through the primary brine discharge pump 8, the secondary brine discharge pump 9 and the brine pipeline, and finally supplied externally.

[0030] Further, a brine replenishment pipeline 20 is connected to the primary brine pipeline 17, and the other end of the brine replenishment pipeline 20 is connected to the downcomer 12 or the lower header 4. After being heated by steam regenerative heating stage by stage or stage by stage from the low-temperature effect to the high-temperature effect, the brine enters the downcomer 12 or the lower header 4 of the solar collector 3 through the brine replenishment pipeline 20, mixes with the brine in the downcomer 12 and enters the solar collector 3, absorbs solar heat in the solar collector 3, and evaporates steam. The brine and steam enter the steam-water separator 5, and after separation, part of the brine enters the downcomer 12 for recycling and heating. Each effect evaporator of the evaporator 1 is provided with a brine flash tank 21. The overflow port of the steam-water separator 5 is connected to the brine flash tank 21 of the first effect evaporator, and the brine flash tanks 21 of each effect evaporator are connected in sequence. The secondary brine discharge port is located in the brine flash tank 21 of the last effect evaporator. The excess brine in the steam-water separator 5 overflows to the brine flash tank 21 of the first effect evaporator through the overflow port. The brine flash tank 21 and the multi-effect brine of the evaporator 1 are divided into different brine channels. The high-temperature brine in the brine flash tank 21 is depressurized and flashed to generate part of the steam, and the remaining brine enters the next-effect brine flash tank, is discharged stage by stage, and flashes to generate steam stage by stage.

[0031] More specifically, as Figure 1 shown, the bottom of each effect evaporator has three relatively independent and separated parts, namely, the brine tank directly below the material water spraying device 15, the brine flash tank 21, and the aforementioned condensate tank; between each effect evaporator, the same type of water tanks are connected in sequence through pipelines. The primary brine discharge port is located in the brine tank. In the embodiment, the brine tank, the brine flash tank 21, and the condensate tank are arranged in sequence along the upstream to downstream direction.

[0032] The vacuum system includes a vacuum pipeline 19. The condenser 2 is connected to the vacuum pipeline 19, and a vacuum pump 6 is provided in the vacuum pipeline 19.

[0033] The main function of the vacuum system is to establish a vacuum during startup and timely extract the non-condensable gases of the equipment during operation to maintain the operating vacuum degree of the system. Based on the structure in which the evaporator 1 and the condenser 2 are connected in sequence, the non-condensable gases are discharged stage by stage and finally discharged to the condenser 2, and then discharged from the system through the vacuum pump 6. Further, when the number of effects is large, multi-effect grouped discharge can be adopted, that is, several effects in the multi-effect evaporators of the evaporator 1 are taken as a group. There are several such groups divided. Each effect evaporator in each group is connected with a non-condensable gas discharge pipeline, and the non-condensable gas discharge pipeline is directly connected to the condenser 2, so that the non-condensable gases of each group of low-temperature effects are directly discharged into the condenser 2, thus reducing the situation that the large amount of non-condensable gases between effects affects heat transfer.

[0034] In summary, the novel island solar-thermal and photovoltaic seawater desalination system of the present utility model proposes the concept of combining two process methods, namely low-temperature multi-effect and multi-stage flash evaporation, to improve the overall thermal efficiency, and uses the heat of solar energy for seawater desalination. The combined process method of low-temperature multi-effect and multi-stage flash evaporation can relatively increase the concentration ratio without affecting the boiling point elevation value of the low-temperature multi-effect part. At the same time, the fresh water output is slightly increased by the single-stage flash evaporation of the concentrated brine. This solution has the characteristics of easy access to heat sources, low operating temperature, complex technology but simple operation. It should be noted that all the device components used in this solution can adopt existing technologies, so the specific structures thereof will not be elaborated in detail. In addition, the device components can be increased, decreased, replaced, etc. based on actual needs on the basis of this solution, and these changes do not deviate from the concept of the present utility model.

Claims

1. A novel island solar-thermal and photovoltaic seawater desalination system, characterized in that, It includes a steam generation and heating evaporation system, a circulating cooling and material water system, a finished water system, a concentrated brine system, and a vacuum system, where: The steam generation and heating evaporation system includes a solar collector (3) arranged obliquely. A lower header (4) is connected to the lower part of the solar collector (3), and a steam-water separator (5) is connected to the upper part of the solar collector (3). The steam-water separator (5) is connected to the lower header (4) through a downcomer (12). It also includes an evaporator (1), and the evaporator (1) is a multi-effect evaporator. The steam discharge port of the steam-water separator (5) is connected to the first-effect evaporator of the evaporator (1), and the last-effect evaporator of the evaporator (1) is connected to a condenser (2). The circulating cooling and material water system includes a seawater pipeline (13). The condenser (2) is located on the seawater pipeline (13). A seawater booster pump (7) is connected to the condenser (2) through the seawater pipeline (13). The condenser (2) is connected to a brine heater (11) through the seawater pipeline (13) and a material water pipeline (14). The material water pipeline (14) is connected to the material water spraying devices (15) of each effect evaporator in the evaporator (1). The finished water system includes a finished water pipeline (16). The finished water discharge port of the last-effect evaporator of the evaporator (1) is connected to the condenser (2), and the condenser (2) is connected to the finished water pipeline (16). A finished water pump (10) is arranged in the finished water pipeline (16). The concentrated brine system includes a primary brine pipeline (17) and a secondary brine pipeline (18). The primary brine discharge port of the last-effect evaporator of the evaporator (1) is connected to the brine heater (11) through the primary brine pipeline (17), and a primary brine discharge pump (8) is arranged in the primary brine pipeline (17). The secondary brine discharge port of the last-effect evaporator of the evaporator (1) is connected to the secondary brine pipeline (18). The brine heater (11) is located on the secondary brine pipeline (18), and a secondary brine discharge pump (9) is also arranged in the secondary brine pipeline (18). The vacuum system includes a vacuum pipeline (19). The condenser (2) is connected to the vacuum pipeline (19), and a vacuum pump (6) is arranged in the vacuum pipeline (19).

2. The novel island solar-thermal and photovoltaic seawater desalination system according to claim 1, characterized in that The steam-water separator (5) has an overflow port, and the overflow port is connected to the first-effect evaporator of the evaporator (1).

3. The novel island solar-thermal and photovoltaic seawater desalination system according to claim 2, wherein, Each effect evaporator of the evaporator (1) has a brine flash tank (21). The overflow port of the steam-water separator (5) is connected to the brine flash tank (21) of the first-effect evaporator, and the brine flash tanks (21) of each effect evaporator are connected in sequence.

4. The novel island solar-thermal and photovoltaic seawater desalination system according to claim 3, characterized in that, The secondary brine discharge port is located at the brine flash tank (21) of the last-effect evaporator.

5. The novel island solar-thermal and photovoltaic seawater desalination system according to claim 1, characterized in that A brine make-up pipeline (20) is connected to the primary brine pipeline (17), and the other end of the brine make-up pipeline (20) is connected to the downcomer (12) or the lower header (4).

6. The novel island solar-thermal and photovoltaic seawater desalination system according to any one of claims 1-5, characterized in that, The multi-effect evaporator of the evaporator (1) is divided into several groups, and each effect evaporator of each group is connected to a non-condensable gas discharge pipeline, and the non-condensable gas discharge pipeline is connected to the condenser (2).

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