阅读说明：本技术 高盐废水利用光热蒸发结晶的系统及方法 (System and method for high-salinity wastewater through photo-thermal evaporation crystallization ) 是由 田江南 张恬 李红军 罗扬 徐淑姣 周军 刘军梅 于 2020-06-16 设计创作，主要内容包括：本发明高盐废水利用光热蒸发结晶的系统及方法,包含高盐废水输送装置,高盐废水输送装置连接扩容蒸发装置,扩容蒸发装置连接蒸发结晶装置；高盐废水输送装置具有预热水输入端和预热水输出端；还设置有槽式抛物面聚光集热单元,该槽式抛物面聚光集热单元通过导热油循环管路依序连接扩容蒸发装置和蒸发结晶装置,并连接回槽式抛物面聚光集热单元；槽式抛物面聚光集热单元还连接熔盐储热单元。本发明处理高盐废水依靠光热系统提供热源,热源主要来自太阳能,符合绿色环保的可持续发展理念。(The invention relates to a system and a method for crystallizing high-salinity wastewater by utilizing photo-thermal evaporation, which comprises a high-salinity wastewater conveying device, wherein the high-salinity wastewater conveying device is connected with a capacity expansion evaporation device; the high-salinity wastewater conveying device is provided with a preheated water input end and a preheated water output end; the trough parabolic light and heat collecting unit is connected with the expansion evaporation device and the evaporation crystallization device in sequence through a heat conducting oil circulating pipeline and is connected back to the trough parabolic light and heat collecting unit; the groove type paraboloid light and heat gathering unit is also connected with the molten salt heat storage unit. The method for treating the high-salinity wastewater provides a heat source by depending on a photo-thermal system, the heat source is mainly from solar energy, and the method conforms to the sustainable development concept of green and environmental protection.)

1. A system for high-salinity wastewater evaporation crystallization by utilizing photo-thermal energy is characterized by comprising a high-salinity wastewater conveying device, wherein the high-salinity wastewater conveying device is connected with a capacity expansion evaporation device which is connected with an evaporation crystallization device; the high-salinity wastewater conveying device is provided with a preheated water input end and a preheated water output end;

the trough parabolic light and heat collecting unit is connected with the expansion evaporation device and the evaporation crystallization device in sequence through a heat conducting oil circulating pipeline and is connected back to the trough parabolic light and heat collecting unit; the groove type paraboloid light and heat gathering unit is also connected with the molten salt heat storage unit.

2. The system for high-salinity wastewater crystallization by utilizing photothermal evaporation as claimed in claim 1, wherein the volume expansion evaporation device and the evaporative crystallization device are provided with steam output ends, the steam output ends are connected with the preheated water input ends of the high-salinity wastewater delivery devices, and the preheated water output ends are connected with the distilled water collection unit.

3. The method for crystallizing the high-salt wastewater by utilizing the photothermal evaporation is characterized in that the high-salt wastewater is conveyed to a capacity expansion evaporation device through a high-salt wastewater conveying device, and the high-salt wastewater is concentrated and reduced; then sending the salt into an evaporative crystallization device to finish crystallization and solidification of the salt, and obtaining crystallized salt; the expansion evaporation device and the evaporation crystallization device simultaneously generate steam to obtain distilled water;

the groove type paraboloid light-gathering and heat-collecting unit absorbs sunlight heat, the heat is sequentially conveyed to the expansion evaporation device and the evaporation crystallization device through the heat conduction oil circulation pipeline to provide heat for the expansion evaporation device and the evaporation crystallization device, and redundant heat is stored through the molten salt heat storage unit and is released when no solar energy exists, so that the continuous operation of the whole system is ensured.

4. The method for crystallizing high-salt wastewater through photothermal evaporation according to claim 3, wherein the steam generated by the flash evaporation device and the evaporative crystallization device is used for preheating the high-salt wastewater, and the steam is changed into distilled water for recycling after preheating; the temperature range of the steam is 50-80 ℃, and the pressure range of the steam is 0.07-0.09 MPa.

5. The method for high-salinity wastewater photo-thermal evaporative crystallization according to claim 3, wherein the salt content of the high-salinity wastewater entering the evaporative crystallization device is more than 10000mg/L, the COD of the high-salinity wastewater is less than 100mg/L, and the suspended matter content of the high-salinity wastewater is less than 100 mg/L.

6. The method for high salinity wastewater evaporation crystallization by utilizing photothermal energy according to claim 3, wherein the heat conducting oil is heated to 400-500 ℃ by the trough-type parabolic light-gathering and heat-collecting unit, and the temperature is reduced to 100-200 ℃ after heat exchange between the expansion evaporation device and the evaporation crystallization device.

7. The method for crystallizing high-salinity wastewater by utilizing photothermal evaporation according to claim 3, wherein the steam-water ratio of the flash evaporation system is in the range of 1:3 to 1: 5.

8. The method for high-salinity wastewater photo-thermal evaporative crystallization according to claim 3, wherein the water generation ratio of the evaporative crystallization device is more than 10.

Technical Field

The invention relates to the field of water treatment, in particular to a system and a method for treating high-salinity wastewater.

Background

China issued action plans for preventing and treating water pollution (ten water items) in 2015, which marks that the state puts higher requirements on the treatment of water pollution. With the increasing restriction of the use of water resources by various industrial plans, the direct discharge of wastewater is prohibited in many areas, and the zero discharge and the recycling of wastewater become a new normal state. The high-salinity wastewater has the characteristics of high corrosivity, serious harm to the environment, complex treatment process, high treatment energy consumption and the like. Therefore, the treatment of high salinity wastewater has been a problem.

For example, patent publication No. CN 209835696U discloses a system for treating desulfurization wastewater of coal-fired power plants by using solar photothermal technology. It is known that desulfurized waste water belongs to high-salinity waste water. The system comprises an annular Fresnel solar condenser, a molten salt heat exchanger, a dilatation evaporator, a jet concentrator and the like. The system can realize the crystallization and solidification of the desulfurization wastewater, but the system is based on a coal-fired power plant and heats the desulfurization wastewater by using the waste heat of the flue. The system cannot operate if it is disconnected from the coal fired power plant.

The invention patent (patent publication No. CN 110332086A) reports a solar energy hot water cogeneration process. The system comprises a condenser, a heat collecting tower, a heat medium storage tank, a steam generator, a cold medium storage tank, a seawater/brackish water desalination system, a turbine generator, a booster transformer, desalinated water storage and the like. It is well known that seawater is a high salt water. And all the low-temperature waste heat steam after power generation enters a seawater/brackish water desalination system, the low-temperature waste heat steam is used as a heat source of a low-temperature multi-effect evaporation system to be fully utilized for desalinating seawater or brackish water again, distilled water produced by the desalination system enters a desalinated water storage tank, one part of the distilled water is used as production water of a photo-thermal power plant and is conveyed to a turbine generator of a power generation system, and the other part of the distilled water is used as urban residents and other industrial water. The seawater/brackish water desalination system adopts all low-temperature waste heat steam after power generation as a heat source, the grade of the waste heat steam is low, and the requirement cannot be met if the seawater/brackish water desalination system is used for treating high-salinity wastewater.

Disclosure of Invention

The invention mainly aims to provide a system and a method for treating high-salinity wastewater by utilizing photothermal evaporation crystallization.

The technical means adopted by the invention are as follows.

A system for high-salinity wastewater evaporation crystallization by utilizing photo-thermal energy comprises a high-salinity wastewater conveying device, wherein the high-salinity wastewater conveying device is connected with a capacity expansion evaporation device, and the capacity expansion evaporation device is connected with an evaporation crystallization device; the high-salinity wastewater conveying device is provided with a preheated water input end and a preheated water output end; the trough parabolic light and heat collecting unit is connected with the expansion evaporation device and the evaporation crystallization device in sequence through a heat conducting oil circulating pipeline and is connected back to the trough parabolic light and heat collecting unit; the groove type paraboloid light and heat gathering unit is also connected with the molten salt heat storage unit.

The expansion evaporation device and the evaporation crystallization device are provided with steam output ends, the steam output ends are connected with the preheated water input ends of the high-salinity wastewater conveying devices, and the preheated water output ends are connected with the distilled water collecting unit.

Conveying the high-salinity wastewater to an expansion evaporation device through a high-salinity wastewater conveying device, and concentrating and reducing the high-salinity wastewater; then sending the salt into an evaporative crystallization device to finish crystallization and solidification of the salt, and obtaining crystallized salt; the expansion evaporation device and the evaporation crystallization device simultaneously generate steam to obtain distilled water; the groove type paraboloid light-gathering and heat-collecting unit absorbs sunlight heat, the heat is sequentially conveyed to the expansion evaporation device and the evaporation crystallization device through the heat conduction oil circulation pipeline to provide heat for the expansion evaporation device and the evaporation crystallization device, and redundant heat is stored through the molten salt heat storage unit and is released when no solar energy exists, so that the continuous operation of the whole system is ensured.

Steam generated by the capacity-expanding evaporation device and the evaporation crystallization device is used for preheating the high-salinity wastewater, and the preheated steam is changed into distilled water for recycling; the temperature range of the steam is 50-80 ℃, and the pressure range of the steam is 0.07-0.09 MPa.

The salt content of the high-salt wastewater entering the evaporative crystallization device is more than 10000mg/L, the COD of the high-salt wastewater is less than 100mg/L, and the content of suspended matters in the high-salt wastewater is less than 100 mg/L.

The heat conducting oil is heated to 400-plus-500 ℃ by the groove-type paraboloid light-gathering heat-collecting unit, and the temperature is reduced to 100-plus-200 ℃ after heat exchange by the expansion evaporation device and the evaporation crystallization device.

The steam-water ratio of the expansion evaporation system is 1:3-1: 5.

The water making ratio of the evaporative crystallization device is more than 10.

The invention has the beneficial effects that: the high-salinity wastewater treatment system provides a heat source by means of a photo-thermal system, the heat source mainly comes from solar energy, and the sustainable development concept of green and environmental protection is met. No additional consumption of chemicals and no environmental pollution. The product is crystallized salt and distilled water, and both products can be sold, so that high additional value is brought.

Drawings

FIG. 1 is a schematic diagram of the system of the present invention.

Detailed Description

Referring to fig. 1, the system for high-salinity wastewater evaporation crystallization by using photo-thermal energy of the present invention includes a high-salinity wastewater delivery device 1, the high-salinity wastewater delivery device 1 is connected to a flash evaporation device 2, and the flash evaporation device 2 is connected to an evaporation crystallization device 3; the high-salinity wastewater conveying device 1 is provided with a preheated water input end 11 and a preheated water output end 12; the trough parabolic light and heat collecting unit 4 is also arranged, and the trough parabolic light and heat collecting unit 4 is sequentially connected with the expansion evaporation device 2 and the evaporation crystallization device 3 through a heat conducting oil circulating pipeline 5 and is connected back to the trough parabolic light and heat collecting unit 4; the trough type paraboloid light and heat gathering unit 4 is also connected with a molten salt heat storage unit 6. The trough type paraboloid light and heat gathering unit, the heat conducting oil circulation pipeline and the molten salt heat storage unit form a light and heat system. The expansion evaporation device and the evaporation crystallization device are both existing mature equipment, the expansion evaporation device aims at concentrating and reducing the high-salinity wastewater, and the evaporation crystallization device is preferably a multi-stage flash evaporation device and aims at realizing the final separation of salt and water in the high-salinity wastewater and finishing the crystallization and solidification of salt.

In order to save energy and efficiently utilize resources, the high-salinity wastewater is preheated by the steam generated by the expansion evaporation device and the steam generated by the evaporation crystallization device.

The expansion evaporation device 2 and the evaporation crystallization device 3 are provided with a steam output end 7, the steam output end 7 is connected with a preheated water input end 11 of the high-salinity wastewater conveying device 1, and a preheated water output end 12 is connected with a distilled water collecting unit 8.

A return pipeline 21 can be further arranged between the expansion evaporation device 2 and the evaporation crystallization device 3 to be connected between the high-salt wastewater input device 1 and the expansion evaporation device 2, so that the high-salt wastewater which does not meet the evaporation crystallization requirement is refluxed and reprocessed.

The related equipment used by the invention is the existing mature equipment.

The invention also provides a method for utilizing the photothermal evaporation crystallization of the high-salinity wastewater, which is characterized in that the high-salinity wastewater is conveyed to the expansion evaporation device through the high-salinity wastewater conveying device, and the high-salinity wastewater is concentrated and reduced; then sending the salt into an evaporative crystallization device to finish crystallization and solidification of the salt, and obtaining crystallized salt; the expansion evaporation device and the evaporation crystallization device simultaneously generate steam to obtain distilled water; the groove type paraboloid light-gathering and heat-collecting unit absorbs sunlight heat, the heat is sequentially conveyed to the expansion evaporation device and the evaporation crystallization device through the heat conduction oil circulation pipeline to provide heat for the expansion evaporation device and the evaporation crystallization device, and redundant heat is stored through the molten salt heat storage unit and is released when no solar energy exists, so that the continuous operation of the whole system is ensured. The expansion evaporation device and the evaporation crystallization device are both existing mature equipment, the expansion evaporation device aims at concentrating and reducing the high-salinity wastewater, and the evaporation crystallization device is preferably a multi-stage flash evaporation device and aims at realizing the final separation of salt and water in the high-salinity wastewater and finishing the crystallization and solidification of salt.

The steam that dilatation evaporation plant and evaporation crystallization device produced is used for preheating high salt waste water, and high salt waste water is preheating and need absorbing certain heat, if absorbed the waste heat of steam, then just can absorb some solar photo-thermal system's heat less, then solar photo-thermal system's construction scale just can be a little. The preheated steam is changed into distilled water for recovery, the temperature range of the steam is 50-80 ℃, and the pressure range of the steam is 0.07-0.09 MPa. The salt content of the distilled water is less than 10mg/L, and may be, for example, 9 mg/L, 8 mg/L, 7mg/L, etc., preferably 5 mg/L.

The salt-containing wastewater can be: high-salinity wastewater in chemical industry, printing and dyeing, papermaking, pharmacy and other industries. The salt content of the high-salt wastewater entering the evaporative crystallization device is more than 10000mg/L, for example, 10000, 20000, 30000mg/L, preferably 50000 mg/L. In order to further improve the concentration efficiency of the system and reduce the investment cost of a multi-stage flash evaporation device (because the multi-stage flash evaporation is a complete system), the concentration of the high-salinity wastewater before entering the multi-stage flash evaporation is further concentrated. Therefore, the flash evaporation is firstly carried out, and then the multistage flash evaporation is carried out. If the salt content of the high-salt wastewater is less than 10000mg/L, the wastewater needs to be forcibly evaporated for a plurality of times at the expansion evaporation device. And the next stage of process (namely a multistage flash evaporation device) can be carried out until the salt content is more than 10000 mg/L.

The COD of the high-salt wastewater entering the evaporative crystallization device is less than 100mg/L, for example, 50 mg/L, 30mg/L, 10mg/L and the like, preferably 10 mg/L.

The content of suspended matters of the high-salt wastewater entering the evaporative crystallization device is less than 100mg/L, for example, 50 mg/L, 30mg/L, 10mg/L and the like, preferably 10 mg/L.

The heat conducting oil is heated to 400-plus-500 ℃ by the groove-type paraboloid light-gathering heat-collecting unit, and the temperature is reduced to 100-plus-200 ℃ after heat exchange by the expansion evaporation device and the evaporation crystallization device.

The steam-water ratio of the expansion evaporation device is 1:3-1: 5. The water making ratio of the evaporative crystallization device is more than 10.