A hydrocarbon removal system for electro-desalination wastewater

Abstract

The utility model relates to a kind of electric desalting wastewater dehydrocarbon systems, comprising: dehydrocarbon tank, the dehydrocarbon tank one side upper region is arranged dehydrocarbon flow, dehydrocarbon tank bottom is arranged wastewater drainage flow;The dehydrocarbon flow is arranged primary heat exchange device, the wastewater drainage flow is arranged secondary heat exchange device and desalination drainage cooling device, secondary heat exchange device bottom is connected to desalination drainage cooling device by pipeline, desalination drainage cooling device bottom is connected to sewage treatment plant system by pipeline;The system utilizes flash evaporation principle to flash out the light hydrocarbon type non-condensable gas entrained in electric desalting wastewater in dehydrocarbon tank, as fuel gas is discharged to low-pressure gas pipe network;Purified electric desalting wastewater is discharged to sewage plant, effectively solve the problem that the gas phase space hydrocarbon content is high when electric desalting wastewater of atmospheric-vacuum unit is discharged to sewage treatment plant, reduce the VOCs detection value of the plant area, improve the environmental protection index of sewage treatment plant area.

Description

Technical Field

[0001] This utility model relates to an electrostatic desalination wastewater dehydrocarbon removal system for dehydrocarbon removal from electrostatic desalination wastewater in atmospheric and vacuum distillation units, belonging to the field of environmental protection and energy-saving technology of atmospheric and vacuum distillation units. Background Technology

[0002] In the existing technology for dehydrocarbon removal from wastewater in atmospheric and vacuum distillation units, the wastewater is directly discharged to the wastewater treatment plant after heat exchange and cooling. This causes the non-condensable hydrocarbons carried in the wastewater to volatilize after being discharged to the wastewater treatment plant, polluting the environment and posing certain safety hazards. Utility Model Content

[0003] In view of the technical problems existing in the discharge process of the electrostatic desalination wastewater from the above-mentioned atmospheric and vacuum distillation unit, the purpose of this utility model is to provide an electrostatic desalination wastewater dehydrocarbonization system, which flash-evaporates the light hydrocarbon non-condensable gases entrained in the electrostatic desalination wastewater in the dehydrocarbonization tank. This can effectively solve the problem of high hydrocarbon content in the gas phase space when the electrostatic desalination wastewater from the atmospheric and vacuum distillation unit is discharged to the sewage treatment plant, thereby improving environmental quality, reducing the risk of combustion and explosion, and achieving the purpose of energy saving and consumption reduction to a certain extent.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is: an electro-desalination wastewater dehydrocarbonization system, comprising: a dehydrocarbonization tank, a dehydrocarbonization process is provided in the upper part of one side of the dehydrocarbonization tank, and a wastewater drainage process is provided at the bottom of the dehydrocarbonization tank; a primary heat exchange device is provided in the dehydrocarbonization process, the bottom of the primary heat exchange device is connected to the feed pipeline of the dehydrocarbonization tank through a pipeline, the feed pipeline is connected to the dehydrocarbonization tank, and the top of the dehydrocarbonization tank is connected to a low-pressure gas system through a pipeline; The wastewater discharge process is equipped with a secondary heat exchange device and a desalination drainage cooling device. The bottom of the dehydrogenation tank is connected to a wastewater discharge pipeline. A dehydrogenation drainage pump is installed on the wastewater discharge pipeline. The end of the wastewater discharge pipeline is connected to the secondary heat exchange device. The bottom of the secondary heat exchange device is connected to the desalination drainage cooling device through a pipeline. The bottom of the desalination drainage cooling device is connected to the sewage treatment plant system through a pipeline. Furthermore, the primary heat exchange device is a primary desalination water injection-drainage heat exchanger, the secondary heat exchange device is a secondary desalination water injection-drainage heat exchanger, and the desalination drainage cooling device is a desalination drainage cooler. Furthermore, a feed line control valve is installed at the root of the dehydrogenation tank feed line and near the bottom of the primary desalination water injection-drainage heat exchanger. Furthermore, a wastewater drainage pipeline control valve is installed at the end of the wastewater drainage pipeline at the bottom of the dehydrogenation tank; Furthermore, a first gate valve and a second gate valve are sequentially connected to the bottom pipeline of the primary desalination water injection-drainage heat exchanger, and the end of the wastewater drainage pipeline is connected to the bottom pipeline of the primary desalination water injection-drainage heat exchanger between the first and second gate valves. When the dehydrogenation process is started, the first gate valve is closed when the electric desalination wastewater after the primary heat exchange flows through the feed pipeline of the dehydrogenation tank. When the wastewater drainage process is started, the first gate valve is closed and the second gate valve is open when the purified wastewater flows through the wastewater drainage pipeline to the secondary desalination water injection-drainage heat exchanger.

[0005] Furthermore, a temperature control line is led out from the bottom pipeline of the desalination drainage cooler to the feed pipeline of the dehydrogenation tank.

[0006] Furthermore, a temperature indicator is installed on the feed line to the dehydrogenation tank near the dehydrogenation tank, and the temperature indicator is connected via an electrical signal from the controller.

[0007] Furthermore, the wastewater drainage pipeline of the aforementioned wastewater drainage process is also branched with a return pipeline, the end of which is connected to the dehydrocarbonization tank. Furthermore, a pneumatic regulating valve is installed on the return pipeline, and the flow controller is electrically connected through the pneumatic regulating valve to realize flow measurement; Furthermore, a pneumatic regulating valve is installed between the dehydrogenation drainage pump on the wastewater drainage pipeline and the wastewater drainage pipeline control valve. The pneumatic regulating valve is electrically connected to a liquid level controller located near the lower side wall of the dehydrogenation tank to control the liquid level inside the dehydrogenation tank.

[0008] The workflow of the electro-desalination wastewater hydrocarbon removal system with the above structure is as follows: The 130℃ desalination wastewater is cooled to about 80℃ through a primary desalination water injection-drainage heat exchanger (E051AB) and then led to the dehydrogenation tank (V053) for flash evaporation. After being evenly distributed by the distributor on the top of the tank, it is sprayed downwards. The tank pressure is controlled at 15-20kPa. During this process, the non-condensable hydrocarbons entrained in the wastewater are flashed out. The flashed hydrocarbons enter the desulfurization system from the top of the tank for desulfurization and are then sent to the low-pressure gas system. The purified wastewater at the bottom of the tank is pressurized by the dehydrogenation drainage pump (P055AB), and part of it flows back to the dehydrogenation tank. The other part is cooled to below 40℃ through a secondary desalination water injection-drainage heat exchanger (E051CD) and a desalination drainage cooler (E052AB) and then sent to the sewage treatment plant.

[0009] The beneficial effects of this utility model are: This system utilizes the flash evaporation principle to remove light hydrocarbon non-condensable gases entrained in the electrostatic precipitator wastewater in a dehydrogenation tank, which are then discharged as fuel gas into the low-pressure gas pipeline network. The purified electrostatic precipitator wastewater is discharged to the wastewater treatment plant, effectively solving the problem of high hydrocarbon content in the gas phase space when electrostatic precipitator wastewater from atmospheric and vacuum distillation units is discharged to the wastewater treatment plant. This reduces the VOCs detection value of the plant area and improves the environmental protection indicators of the wastewater treatment plant area. It also reduces the hydrocarbon content in the electrostatic precipitator wastewater, thereby reducing the volatilization and accumulation of hydrocarbons after the wastewater is discharged to the wastewater treatment plant and reducing the safety hazards caused by the accumulation of combustible gas in the wastewater treatment plant. The removed hydrocarbon non-condensable gases are recovered and used as fuel gas, which is beneficial to the energy conservation and consumption reduction of the entire plant. Attached Figure Description

[0010] Figure 1 This is a structural diagram of the present invention.

[0011] In the diagram, 1. Dehydrocarbonation tank, 2. Dehydrocarbonation tank feed line, 3. Wastewater drainage line, 4. Dehydrocarbonation drainage pump, 5. Primary desalination water injection-drainage heat exchanger, 6. Secondary desalination water injection-drainage heat exchanger, 7. Desalination drainage cooler, 8. Feed line control valve, 9. Wastewater drainage line control valve, 10. First gate valve, 11. Second gate valve, 12. Temperature control line, 13. Temperature indicator, 14. Return line, 15. Flow controller, 16. Level controller. Detailed Implementation

[0012] To make the above-mentioned objects, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a full understanding of this utility model. However, this utility model can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this utility model. Therefore, this utility model is not limited to the specific embodiments disclosed below.

[0013] like Figure 1 An electro-desalination wastewater dehydrocarbonization system is shown, comprising: a dehydrocarbonization tank 1, with a dehydrocarbonization process in the upper part of one side of the dehydrocarbonization tank 1 and a wastewater drainage process at the bottom of the dehydrocarbonization tank 1; a primary heat exchanger is installed in the dehydrocarbonization process, the bottom of the primary heat exchanger is connected to the feed pipeline 2 of the dehydrocarbonization tank via a pipeline, the feed pipeline 2 is connected to the dehydrocarbonization tank 1, and the top of the dehydrocarbonization tank 1 is connected to the low-pressure gas system via a pipeline; based on the dehydrocarbonization process, the electro-desalination wastewater, after heat exchange in the primary heat exchanger, is led to the dehydrocarbonization tank 1 for flash evaporation, and the non-condensable hydrocarbon gases flashed out enter the desulfurization system for desulfurization before being discharged to the low-pressure gas system. The wastewater discharge process includes a secondary heat exchanger and a desalination drainage cooling device. The bottom of the dehydrocarbon removal tank 1 is connected to the wastewater discharge pipeline 3, and a dehydrocarbon removal pump 4 is installed on the wastewater discharge pipeline 3. The end of the wastewater discharge pipeline 3 is connected to the secondary heat exchanger via a pipeline. The bottom of the secondary heat exchanger is connected to the desalination drainage cooling device via a pipeline. The bottom of the desalination drainage cooling device is connected to the sewage treatment plant system via a pipeline. Based on the wastewater discharge process, the purified wastewater after dehydrocarbon removal undergoes secondary heat exchange through the secondary heat exchanger and is finally cooled by the desalination drainage cooling device before being sent to the sewage treatment plant. Furthermore, the primary heat exchange device is a primary desalination water injection-drainage heat exchanger 5, the secondary heat exchange device is a secondary desalination water injection-drainage heat exchanger 6, and the desalination drainage cooling device is a desalination drainage cooler 7. Furthermore, a feed line control valve 8 is installed at the root of the dehydrogenation tank feed line 2 and near the bottom of the primary desalination water injection-drainage heat exchanger 5. The flow of drainage in the feed line 2 is controlled by this control valve. Furthermore, a wastewater drainage pipeline control valve 9 is installed at the end of the wastewater drainage pipeline 3 at the bottom of the dehydrocarbonation tank 1. The purified electro-desalination wastewater is controlled by this control valve as it flows through the wastewater drainage pipeline 3. Furthermore, a first gate valve 10 and a second gate valve 11 are sequentially connected to the bottom pipeline of the primary desalination water injection-drainage heat exchanger 5, and the end of the wastewater drainage pipeline 3 is connected to the bottom pipeline of the primary desalination water injection-drainage heat exchanger 5 between the first gate valve 10 and the second gate valve 11. When the dehydrogenation process is started, the first gate valve 10 is closed when the electric desalination wastewater after the primary heat exchange flows through the dehydrogenation tank feed pipeline 2. When the wastewater drainage process is started, the first gate valve 10 is closed and the second gate valve 11 is opened when the purified wastewater flows through the wastewater drainage pipeline 3 to the secondary desalination water injection-drainage heat exchanger 6.

[0014] Furthermore, a temperature control line 12 is led out from the bottom pipeline of the desalination wastewater cooler 7 to the feed pipeline 2 of the dehydrogenation tank to adjust the feed temperature of the dehydrogenation tank 1 and prevent the temperature of the electro-desalination wastewater entering the dehydrogenation tank 1 from being too high.

[0015] Furthermore, a temperature indicator 13 is installed on the feed line 2 of the dehydrogenation tank near the dehydrogenation tank 1 to display the temperature value at that measuring point; the temperature indicator 13 is connected via an electrical signal from the controller.

[0016] Furthermore, the wastewater drainage pipeline 3 of the wastewater drainage process is also branched with a return pipeline 14, the end of which is connected to the dehydrogenation tank 1; after the purified wastewater at the bottom of the dehydrogenation tank 1 is pressurized by the dehydrogenation drainage pump 4, a portion of it needs to be returned to the dehydrogenation tank 1 to enhance the removal effect. Furthermore, a pneumatic regulating valve is installed on the return pipeline 14, and the flow controller 15 is electrically connected through the pneumatic regulating valve to realize flow measurement; Furthermore, a pneumatic regulating valve is installed between the dehydrogenation drainage pump 4 on the wastewater drainage pipeline 3 and the wastewater drainage pipeline control valve 9. The pneumatic regulating valve is electrically connected to the liquid level controller 16 near the lower side wall of the dehydrogenation tank 1 to control the liquid level in the dehydrogenation tank 1.

[0017] The workflow of the electro-desalination wastewater hydrocarbon removal system with the above structure is as follows: The 130℃ desalination wastewater is cooled to about 80℃ through the primary desalination water injection-drainage heat exchanger 5 (E051AB) and then led to the dehydrocarbon removal tank 1 for flash evaporation. After being evenly distributed by the distributor on the top of the tank, it is sprayed downwards. The tank pressure is controlled at 15-20kPa. During this process, the non-condensable hydrocarbons entrained in the wastewater are flashed out. The flashed hydrocarbons enter the desulfurization system from the top of the tank for desulfurization and are then sent to the low-pressure gas system. The purified wastewater at the bottom of the tank is pressurized by the dehydrocarbon removal drainage pump 4 (P055AB), and part of it flows back to the dehydrocarbon removal tank 1. The other part is cooled to below 40℃ through the secondary desalination water injection-drainage heat exchanger 6 (E051CD) and the desalination drainage cooler 7 (E052AB) and then sent to the sewage treatment plant.

[0018] This scheme utilizes the flash evaporation principle to carry out online retrofitting of the electrostatic desalination wastewater dehydrocarbonization facility on the existing basis. After the retrofitting was completed, the dehydrocarbonization system was purged and sealed before being put into operation. The dehydrocarbonization effect was significant after the system was put into operation. A comparative analysis of hydrocarbon content data in the desalination wastewater before and after the operation was conducted. The dehydrogenation effect was significant. Before the operation, the hydrocarbon content in the desalination wastewater was between 5000-8000 ppm, and after the operation, the hydrocarbon content in the desalination wastewater was between 50-130 ppm. Through the adjustment and comparison of the feed temperature of the dehydrogenation tank 1 by the temperature control line 12, it was determined that the feed temperature of the dehydrogenation tank 1 is around 80℃. If it is too low, the dehydrogenation effect will decrease, and if it is too high, the dehydrogenation non-condensable gas will contain more water, which will easily lead to freezing in winter. After being put into operation, the non-condensable gas from the dehydrogenation process was tested and found to have a hydrocarbon content as high as 78.16%, which has made a certain contribution to energy conservation and emission reduction.

[0019] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0020] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0021] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0022] In this utility model, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] It should be noted that when an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used herein are for illustrative purposes only and do not represent the only possible implementation.

Claims

1. A system for desalinating wastewater and removing hydrocarbons, characterized in that, include: The dehydrogenation tank has a dehydrogenation process in the upper part of one side and a wastewater drainage process in the bottom. A primary heat exchanger is installed in the dehydrogenation process. The bottom of the primary heat exchanger is connected to the feed pipeline of the dehydrogenation tank via a pipeline. The feed pipeline is connected to the dehydrogenation tank. The top of the dehydrogenation tank is connected to the low-pressure gas system via a pipeline. The wastewater drainage process includes a secondary heat exchange device and a desalination drainage cooling device. The bottom of the dehydrogenation tank is connected to a wastewater drainage pipeline, and a dehydrogenation drainage pump is installed on the wastewater drainage pipeline. The end of the wastewater drainage pipeline is connected to the secondary heat exchange device, the bottom of the secondary heat exchange device is connected to the desalination drainage cooling device, and the bottom of the desalination drainage cooling device is connected to the sewage treatment plant system.

2. The electro-desalination wastewater hydrocarbon removal system according to claim 1, characterized in that: The primary heat exchange device is a primary desalination water injection-drainage heat exchanger, the secondary heat exchange device is a secondary desalination water injection-drainage heat exchanger, and the desalination drainage cooling device is a desalination drainage cooler.

3. The electro-desalination wastewater hydrocarbon removal system according to claim 2, characterized in that: A feed line control valve is installed at the root of the dehydrogenation tank feed line and near the bottom of the primary desalination water injection-drainage heat exchanger.

4. The electro-desalination wastewater hydrocarbon removal system according to claim 1, characterized in that: A wastewater drainage control valve is installed at the end of the wastewater drainage pipeline at the bottom of the dehydrocarbonization tank.

5. The electro-desalination wastewater hydrocarbon removal system according to claim 3, characterized in that: The first gate valve and the second gate valve are connected sequentially on the bottom pipeline of the primary desalination water injection-drainage heat exchanger, and the end of the wastewater drainage pipeline is connected to the bottom pipeline of the primary desalination water injection-drainage heat exchanger between the first gate valve and the second gate valve.

6. The electro-desalination wastewater hydrocarbon removal system according to claim 2, characterized in that: A temperature control line is led out from the bottom pipeline of the desalination drainage cooler to the feed pipeline of the dehydrocarbon removal tank.

7. The electro-desalination wastewater hydrocarbon removal system according to claim 1, characterized in that: A temperature indicator is installed on the feed line of the dehydrogenation tank near the dehydrogenation tank, and the temperature indicator is connected via an electrical signal from the controller.

8. The electro-desalination wastewater hydrocarbon removal system according to claim 1, characterized in that: The wastewater drainage pipeline of the aforementioned wastewater drainage process is also branched into a return pipeline, the end of which is connected to the dehydrocarbonization tank.

9. The electro-desalination wastewater hydrocarbon removal system according to claim 8, characterized in that: A pneumatic regulating valve is installed on the return pipeline, and the flow controller is electrically connected through the pneumatic regulating valve.

10. The electro-desalination wastewater hydrocarbon removal system according to claim 4, characterized in that: A pneumatic regulating valve is installed between the dehydrogenation drainage pump on the wastewater drainage pipeline and the wastewater drainage pipeline control valve. The pneumatic regulating valve is electrically connected to the liquid level controller located near the lower side wall of the dehydrogenation tank.

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