Industrial park high-salinity wastewater concentration system

Abstract

The utility model discloses a high-salinity wastewater concentration system for an industrial park. The high-salinity wastewater concentration system comprises a boiler dead steam discharge pipeline, a condenser, a heat exchange medium circulation pipeline, an indirect cooling tower and a wastewater evaporation concentration tower, a bottom air inlet of the indirect cooling tower is provided with a heat exchange tube grid; a heating pipe is arranged in the wastewater evaporation and concentration tower; the boiler dead steam discharge pipeline passes through the condenser hot end, and the heat exchange medium circulation pipeline passes through the condenser cold end; a heat exchange medium circulating pipeline communicated with an outlet of the cold end of the condenser is divided into two branches, one branch passes through the heat exchange pipe grid, the other branch passes through the heating pipe, and the two branches are converged and then communicated with an inlet of the cold end of the condenser. According to the utility model, boiler dead steam waste heat is used as a heat source for evaporation and concentration of wastewater in an industrial park, so that the wastewater concentration cost of the park is greatly reduced, cooling capacity can be provided for the dead steam cooling process, and energy conservation and emission reduction are realized.

Description

Technical Field

[0001] This utility model relates to the field of energy conservation and environmental protection technology, and in particular to a high-salt wastewater concentration system for industrial parks. Background Technology

[0002] After generating electricity, the exhaust steam discharged from the low-pressure cylinder of the industrial park's thermal power unit needs to be condensed into liquid water through heat exchange equipment such as condensers and cooling towers. This liquid water is then reintroduced into the boiler to generate high-temperature, high-pressure steam for power generation and heating. To reduce energy consumption and water waste during the boiler exhaust steam condensation process, indirect natural draft cooling towers are widely used in thermal power units. However, this operating mode of thermal power units has the following drawbacks:

[0003] (1) The exhaust steam from the boiler that has completed power generation and heating is sent to the indirect natural draft cooling tower. It exchanges heat with the low-temperature ambient air through the indirect heat exchanger. The air density decreases after the heat exchange is completed and the buoyancy is generated, which drives the surrounding ambient air to continuously enter from the bottom of the indirect natural draft cooling tower. A large amount of exhaust steam waste heat is discharged into the ambient air and cannot be utilized, which is the largest heat loss of the thermal power unit.

[0004] (2) The heat exchange effect of indirect natural ventilation cooling towers is greatly affected by the ambient air temperature. In summer, the ambient air temperature is high and the air flow required for heat exchange is large; in winter, the ambient air temperature is low and the air flow required is small. In order to ensure the stable operation of the thermal power unit, the indirect natural ventilation cooling tower of the thermal power unit needs to be designed according to the summer operation mode, resulting in a large design margin for the indirect natural ventilation cooling tower in winter.

[0005] (3) Reducing the exhaust pressure of the low-pressure cylinder of the steam turbine can effectively increase the ideal enthalpy drop of the steam, allowing more heat energy to be converted into mechanical energy in the steam turbine, improving the power generation efficiency of the unit and reducing the waste heat loss of the exhaust steam. However, the heat exchange effect of the existing indirect natural draft cooling tower system on the exhaust steam mainly depends on the temperature difference between the exhaust steam and the ambient air, and cannot specifically control the exhaust pressure of the low-pressure cylinder, resulting in low and unstable power generation efficiency of the unit.

[0006] The indirect natural draft cooling tower system of the thermal power unit in the industrial park emits a large amount of waste heat that cannot be utilized, the low-temperature environment design has a large heat exchange margin, and the exhaust pressure of the low-pressure cylinder of the steam turbine cannot be effectively controlled. These are the main reasons for the high energy consumption, large pollutant emissions, and low power generation efficiency of the thermal power unit in the industrial park. Utility Model Content

[0007] This invention provides a high-salt wastewater concentration system for industrial parks, which utilizes the waste heat from boiler exhaust steam as a heat source for the evaporation and concentration of wastewater in industrial parks. This significantly reduces the cost of wastewater concentration in the parks, while also providing cooling capacity for the exhaust steam cooling process, thus achieving energy conservation and emission reduction.

[0008] The technical solution of this utility model is as follows:

[0009] A high-salt wastewater concentration system for industrial parks includes a boiler exhaust steam pipeline, a condenser, a heat exchange medium circulation pipeline, an intercooler tower, and a wastewater evaporation and concentration tower.

[0010] The air inlet at the bottom of the cooling tower is equipped with a heat exchange tube grid; the wastewater evaporation and concentration tower is equipped with heating tubes.

[0011] The boiler exhaust steam pipeline passes through the hot end of the condenser, and the heat exchange medium circulation pipeline passes through the cold end of the condenser.

[0012] The heat exchange medium circulation pipeline connected to the cold end outlet of the condenser is divided into two branches. One branch passes through the heat exchange grid and the other branch passes through the heating tube. The two branches merge and connect to the cold end inlet of the condenser.

[0013] The working principle of existing coal-fired power plants is as follows: coal combustion heats the water entering the boiler to produce a large amount of high-temperature and high-pressure steam. The high-temperature and high-pressure steam drives the rotors of two to three generators through the steam turbine generator. The rotors are located inside the exciter, which drives the magnetic coils to rotate and generate electricity. After the two to three stages of power generation are completed, the high-temperature and high-pressure steam is continuously cooled and depressurized, and at this time it becomes the power plant exhaust steam. The low-temperature and low-pressure exhaust steam that has completed power generation is then heat-exchanged through the intercooler tower to produce condensate. The condensate is then sent to the boiler to be heated to generate steam for power generation.

[0014] The heat exchange efficiency of indirect cooling towers is greatly affected by ambient air temperature. In summer, the temperature difference between the ambient air and the condenser outlet water is small, requiring a larger heat exchange area to meet the cooling needs of the circulating water. In winter, the ambient air temperature is low, and the temperature difference between the ambient air and the condenser outlet water is large, requiring only a smaller heat exchange area to meet the cooling needs of the circulating water. Indirect cooling towers are often designed for summer operation. In winter, the indirect cooling tower can provide more cooling capacity and has a large heat exchange capacity, while at the same time, a large amount of waste heat discharged from the cooling tower cannot be utilized.

[0015] This invention is based on the existing generator set intercooling system (boiler exhaust steam pipeline, condenser, circulating water pump, intercooling tower). A wastewater evaporation and concentration tower is installed inside the intercooling tower. A high-temperature circulating water line is led out from the heat exchange medium circulation pipeline and sent to the bottom of the wastewater evaporation and concentration tower to heat the wastewater. The specific working process is as follows:

[0016] Low-temperature circulating medium enters the condenser and exchanges heat with the exhaust steam in the boiler exhaust steam discharge pipeline. The exhaust steam condenses to generate pure condensate water. The high-temperature circulating medium that has completed heat exchange and heating is divided into two paths. One path is sent to the heat exchange grid at the bottom of the intercooler tower to exchange heat with the ambient air and cool down. The other path is sent to the bottom of the wastewater evaporation and concentration tower located inside the intercooler tower to exchange heat with the saline wastewater and cool down. The two low-temperature circulating media that have completed cooling are sent to the circulating medium inlet of the condenser through pipelines to continue to circulate and exchange heat with the exhaust steam.

[0017] High-salt wastewater from the industrial park is piped to a wastewater evaporation and concentration tower, where it exchanges heat with the high-temperature heat exchange medium in the heating pipes at the bottom of the tower, thereby increasing the concentration rate of the saline wastewater.

[0018] Preferably, the boiler exhaust steam discharge pipe inlet is connected to the exhaust steam outlet of the low-pressure cylinder of the steam turbine generator, and the condenser condensate outlet is connected to the boiler inlet via a pipe.

[0019] Inside the condenser, the lower the temperature of the circulating medium and the greater the temperature difference between the low-temperature circulating medium and the exhaust steam, the better the heat exchange and cooling effect on the exhaust steam. At the same time, the lower the gas pressure in the low-pressure cylinder and the greater the pressure difference between the inlet and outlet of the low-pressure cylinder, the higher the power generation efficiency.

[0020] Preferably, the wastewater evaporation and concentration tower includes a wastewater receiving tank, a spraying device, and a circulating pump;

[0021] The wastewater receiving tank is located at the bottom of the wastewater evaporation and concentration tower;

[0022] The spraying device is installed inside the tower above the wastewater receiving tank, and the heating pipe is located below the spraying device.

[0023] The wastewater evaporation and concentration tower is equipped with an air outlet at the top and an air inlet below the spray device;

[0024] A wastewater circulation pipeline is installed between the wastewater receiving tank and the spraying device, and a circulation pump is installed on the wastewater circulation pipeline.

[0025] The circulating pump pressurizes the wastewater in the wastewater receiving tank and sends it to the spraying device. The spraying device sprays the wastewater evenly, and the spraying process partially evaporates the wastewater. The resulting concentrated wastewater returns to the wastewater receiving tank under gravity.

[0026] Preferably, the wastewater evaporation and concentration tower is located inside the intercooler tower.

[0027] After exchanging heat with the heat exchange tube grid, the ambient air expands in volume and decreases in density, flowing upwards within the indirect cooling tower. This drives the continuously cooled ambient air outside the indirect cooling tower through the heat exchange tube grid. The wastewater evaporation and concentration tower is located inside the indirect cooling tower. The sprayed wastewater exchanges heat and evaporates with the upward-flowing hot air in a counter-current manner, while simultaneously exchanging heat with the heating tubes located below the spray layer. By controlling the heat exchange temperature within the wastewater evaporation and concentration tower, the concentration rate of saline wastewater is increased.

[0028] Preferably, the wastewater evaporation and concentration tower is further equipped with a level gauge, a conductivity meter, and a hardness meter, which are used to detect the level, conductivity, and hardness of the wastewater in the wastewater receiving tank, respectively.

[0029] Preferably, the wastewater receiving tank is provided with a drain outlet, and an automatic valve is provided at the drain outlet. The automatic valve is interlocked with the signals of the level gauge, conductivity meter, and hardness meter. When the conductivity meter and hardness meter reach the upper limit, the automatic valve opens to realize automatic drainage; when the level gauge reaches the lower limit, the automatic valve closes to stop drainage.

[0030] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0031] The industrial park high-salt wastewater concentration system of this utility model sets the saline wastewater concentration tower in the indirect cooling tower, uses heat exchange tubes to heat the ambient air (the water vapor saturation decreases after the air temperature rises) to increase the spray evaporation rate of high-salt wastewater, and uses a circulating water heat exchanger to control the heat exchange temperature during the spray evaporation process, further increasing the wastewater evaporation rate and reducing the investment and operating costs of the industrial park wastewater concentration system.

[0032] Using the waste heat from the exhaust steam cooling system of a coal-fired power plant as a heat source for the evaporation and concentration of wastewater in the industrial park can significantly reduce the cost of wastewater concentration while also providing cooling capacity for the exhaust steam cooling process. This further reduces the inlet water temperature of the condenser circulating water, lowers the exhaust pressure of the low-pressure cylinder, and improves the power generation efficiency of the coal-fired power plant. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the high-salt wastewater concentration system in an industrial park. Detailed Implementation

[0034] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be noted that the embodiments described below are intended to facilitate the understanding of the present invention and do not constitute any limitation thereof.

[0035] like Figure 1 As shown, the industrial park high-salt wastewater concentration system of this utility model includes a boiler exhaust steam discharge pipeline 1, a condenser 2, a heat exchange medium circulation pipeline 3, an intercooler tower 4, and a wastewater evaporation and concentration tower 5.

[0036] The inlet of boiler exhaust steam pipe 1 is connected to the exhaust steam outlet of the low-pressure cylinder 6 of the steam turbine generator, and the condensate outlet of condenser 2 is connected to the boiler inlet through a pipe.

[0037] The air inlet at the bottom of the intercooling tower 4 is equipped with a heat exchange tube grid 7; the wastewater evaporation and concentration tower 5 is equipped with a heating tube 8.

[0038] The boiler exhaust steam discharge line 1 passes through the hot end of the condenser 2, and the heat exchange medium circulation line 3 passes through the cold end of the condenser 2. The heat exchange medium circulation line connected to the cold end outlet of the condenser 2 is divided into two branches: one branch passes through the heat exchange tube grid 7, and the other branch passes through the heating tube 8. The two branches merge and connect to the cold end inlet of the condenser 2.

[0039] The wastewater evaporation and concentration tower 5 includes a wastewater receiving tank, a spray device 9, and a circulating pump 10. The wastewater receiving tank is located at the bottom of the wastewater evaporation and concentration tower 5. The spray device 9 is located inside the tower above the wastewater receiving tank, and the heating pipe 8 is located below the spray device 9. An air outlet is provided at the top of the wastewater evaporation and concentration tower 5, and an air inlet is provided below the spray device 9. A wastewater circulation pipeline is provided between the wastewater receiving tank and the spray device 9, and a circulating pump 10 is installed on the wastewater circulation pipeline.

[0040] This utility model's high-salt wastewater concentration system for industrial parks is based on the existing generator set intercooling system. The wastewater evaporation and concentration tower 5 is installed inside the intercooling tower 4. A high-temperature circulating water line is led out from the heat exchange medium circulation pipeline 3 and sent to the bottom of the wastewater evaporation and concentration tower 5 to heat the wastewater. The specific process flow is described below.

[0041] The low-temperature circulating medium enters the condenser 2 and exchanges heat with the exhaust steam discharged from the low-pressure cylinder 6. The exhaust steam condenses to generate pure condensate water, which is then sent to the boiler feedwater system. The high-temperature circulating medium, which has completed heat exchange and heating, is divided into two paths. One path is sent to the heat exchange tube grid 7 at the bottom of the intercooler tower 4 to exchange heat with the ambient air and cool down. The other path is sent to the heating tube 8 at the bottom of the wastewater evaporation and concentration tower 5 located inside the intercooler tower 4 to exchange heat with the saline wastewater from the park that is being sprayed and evaporated, and cool down. The two low-temperature circulating media, which have completed cooling, are then sent to the cold end inlet of the condenser 2 through pipelines to continue circulating and exchanging heat with the exhaust steam.

[0042] After the ambient air that has completed heat exchange with the heat exchange tube grid 7 is heated, its volume expands and its density decreases. It flows upward in the intercooler tower 4 and drives the low-temperature ambient air outside the intercooler tower 4 to continuously pass through the heat exchange tube grid 7 and enter the intercooler tower 4.

[0043] High-salt wastewater from the industrial park is piped to the wastewater evaporation and concentration tower 5, and then pumped to the wastewater spraying device 9. It exchanges heat with the air that has been heated in the cooling tower 4 in a countercurrent flow to evaporate the wastewater, and at the same time exchanges heat with the heating pipe 8 located below the spraying device 9. By controlling the heat exchange temperature in the wastewater evaporation and concentration tower 5, the concentration rate of the saline wastewater is increased.

[0044] In addition, the wastewater evaporation and concentration tower 5 is also equipped with a level gauge, a conductivity meter, and a hardness meter, which are used to detect the level, conductivity, and hardness of the wastewater in the wastewater receiving tank, respectively. The wastewater receiving tank is equipped with a drain outlet, which is equipped with an automatic valve. The automatic valve is interlocked with the signals of the level gauge, conductivity meter, and hardness meter. When the conductivity meter and hardness meter reach the upper limit, the automatic valve opens to automatically drain the wastewater; when the level gauge reaches the lower limit, the automatic valve closes to stop the drainage.

[0045] This utility model sets the saline wastewater evaporation and concentration tower 5 in the indirect cooling tower 4, and uses the ambient air heated by the heat exchange tube grid 7 (the water vapor saturation decreases after the air temperature rises) to increase the spray evaporation rate of high saline wastewater. It also uses a circulating medium heat exchanger to control the heat exchange temperature during the spray evaporation process, further increasing the wastewater evaporation rate and reducing the investment and operating costs of the wastewater concentration system in the park.

[0046] Using the waste heat from the exhaust steam cooling system of a coal-fired power plant as a heat source for the evaporation and concentration of wastewater in the industrial park can significantly reduce the cost of wastewater concentration while also providing cooling capacity for the exhaust steam cooling process. This further reduces the inlet water temperature of the condenser circulating medium, lowers the exhaust pressure of the low-pressure cylinder, and improves the power generation efficiency of the coal-fired power plant.

[0047] During operation, the liquid-to-gas ratio in the wastewater evaporation and concentration tower is 3-5 L / Nm³. 3 The temperature of the circulating wastewater is controlled at 40-65℃.

[0048] The embodiments described above provide a detailed explanation of the technical solution and beneficial effects of this utility model. It should be understood that the above descriptions are only specific embodiments of this utility model and are not intended to limit this utility model. Any modifications, additions, and equivalent substitutions made within the scope of the principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A high-salinity wastewater concentration system for industrial parks, characterized in that, This includes boiler exhaust steam pipelines, condensers, heat exchange medium circulation pipelines, intercooler towers, and wastewater evaporation and concentration towers; The air inlet at the bottom of the cooling tower is equipped with a heat exchange tube grid; the wastewater evaporation and concentration tower is equipped with heating tubes. The boiler exhaust steam pipeline passes through the hot end of the condenser, and the heat exchange medium circulation pipeline passes through the cold end of the condenser. The heat exchange medium circulation pipeline connected to the cold end outlet of the condenser is divided into two branches. One branch passes through the heat exchange grid and the other branch passes through the heating tube. The two branches merge and connect to the cold end inlet of the condenser.

2. The industrial park high-salinity wastewater concentration system according to claim 1, characterized in that, The boiler exhaust steam discharge pipeline inlet is connected to the exhaust steam outlet of the low-pressure cylinder of the steam turbine generator, and the condensate outlet of the condenser is connected to the boiler inlet through a pipeline.

3. The industrial park high-salinity wastewater concentration system according to claim 1, characterized in that, The wastewater evaporation and concentration tower includes a wastewater receiving tank, a spraying device, and a circulating pump; The wastewater receiving tank is located at the bottom of the wastewater evaporation and concentration tower; The spraying device is installed inside the tower above the wastewater receiving tank, and the heating pipe is located below the spraying device. The wastewater evaporation and concentration tower is equipped with an air outlet at the top and an air inlet below the spray device; Wastewater circulation pipelines are installed directly between the wastewater receiving tank and the spraying device, and circulation pumps are installed on the wastewater circulation pipelines.

4. The industrial park high-salinity wastewater concentration system according to claim 1, characterized in that, The wastewater evaporation and concentration tower is located inside the intercooler tower.

5. The industrial park high-salinity wastewater concentration system according to claim 1, characterized in that, The wastewater evaporation and concentration tower is also equipped with a level gauge, a conductivity meter, and a hardness meter. The level gauge, conductivity meter, and hardness meter are used to detect the level, conductivity, and hardness of the wastewater in the wastewater receiving tank, respectively.

6. The industrial park high-salinity wastewater concentration system according to claim 5, characterized in that, The wastewater receiving tank is equipped with a drain outlet, and an automatic valve is installed at the drain outlet. The automatic valve is interlocked with the signals of the level gauge, conductivity meter, and hardness meter. When the conductivity meter and hardness meter reach the upper limit, the automatic valve opens to realize automatic drainage; when the level gauge reaches the lower limit, the automatic valve closes to stop drainage.

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