Solvent stripping device for semi-coke wastewater treatment

Abstract

An inlet A of a purified water heat exchanger is connected with an extraction dephenolization wastewater delivery pipe, an outlet A is connected with an extraction dephenolization wastewater inlet of a water tower, an inlet B is connected with a purified water outlet at the bottom of the water tower through a purified water delivery pump, and an outlet B is connected with a purified water delivery pipe; a solvent exhaust port in the top of the water tower is connected with an air inlet of a water tower top cooler, a solvent condensate outlet of the water tower top cooler is connected with a feeding port of an oil-water separator through a solvent condensate pipe, a solvent overflow port of the oil-water separator is connected with a solvent recovery tank, and a water outlet is connected with a backflow port of the water tower through a backflow pump. A first liquid level control valve is arranged on an outlet of the reflux pump, a first liquid level indication control alarm electrically connected with the first liquid level control valve is arranged on the oil-water separator, and a temperature control valve is arranged on a cooling water return pipe of the water tower top cooler. And a temperature indication control alarm electrically connected with the temperature indication control alarm is arranged on the solvent condensate pipe.

Description

Technical Field

[0001] This utility model belongs to the field of semi-coke wastewater treatment technology, specifically relating to a solvent stripping device for semi-coke wastewater treatment. Background Technology

[0002] The production of semi-coke generates a large amount of wastewater containing various harmful substances such as phenols, cyanides, and ammonia nitrogen, causing serious environmental pollution. Extraction-based phenol removal is an important process in semi-coke wastewater treatment. It uses an extractant to separate phenolic substances from the wastewater, thereby reducing its toxicity and improving the efficiency and effectiveness of subsequent treatment. However, the recovery and reuse of the extractant (solvent) is a crucial step in the extraction-based phenol removal process.

[0003] Research has revealed that the wastewater after phenol extraction contains both dissolved solvents and entrained solvents. Traditional methods often employ stripping, a process that uses steam or inert gas to vaporize and separate the dissolved solvents from the wastewater. By introducing steam or inert gas into the wastewater, the solubility of the solvent is reduced, causing it to escape.

[0004] Chinese Patent Application No. 201910159407.1, entitled "A Method and Apparatus for Treating Semi-coke Wastewater", discloses that the wastewater discharged from the extraction tower directly enters the solvent stripping tower for stripping. The temperature of the wastewater discharged from the extraction tower is relatively low, around 50°C, while the stripping temperature of the solvent stripping tower is around 100°C. Therefore, during the stripping process in the solvent stripping tower, the wastewater temperature needs to be raised from 50°C to around 100°C. This process consumes a large amount of steam or inert gas, resulting in high energy consumption. At the same time, the equipment investment and operation and maintenance costs of the stripping tower are also relatively high. Utility Model Content

[0005] The technical problem to be solved by this utility model is to overcome the shortcomings of the prior art and provide a solvent stripping device for treating semi-coke wastewater with low energy consumption and high solvent recovery efficiency.

[0006] The technical solution adopted to solve the above technical problems is: a solvent stripping device for treating semi-coke wastewater, including a water tower for stripping, an inlet A of a purified water heat exchanger connected to an extraction and dephenolization wastewater conveying pipe, an outlet A connected to the extraction and dephenolization wastewater inlet of the water tower, an inlet B connected to the purified water outlet at the bottom of the water tower via a purified water conveying pump, an outlet B connected to a purified water conveying pipe, a solvent exhaust port at the top of the water tower connected to the air inlet of a water tower top cooler, a solvent condensate outlet of the water tower top cooler connected to the inlet of an oil-water separator via a solvent condensate pipe, a solvent overflow port of the oil-water separator connected to a solvent recovery tank, and a drain port connected to the return port of the water tower via a return pump. A first liquid level control valve is installed at the outlet of the return pump, and a first liquid level indicator and control alarm is installed on the oil-water separator. The first liquid level indicator and control alarm is electrically connected to the first liquid level control valve.

[0007] A temperature control valve is installed on the cooling water return pipe of the water tower top cooler, and a temperature indicator and control alarm is installed on the solvent condensate pipe. The temperature indicator and control alarm is electrically connected to the temperature control valve.

[0008] Preferably, a second liquid level indicator and control alarm is installed on the lower side of the water tower, and a second liquid level control valve is installed on the purified water delivery pipe. The second liquid level indicator and control alarm is electrically connected to the second liquid level control valve.

[0009] Preferably, a purified water cooler is installed on the purified water delivery pipe.

[0010] The beneficial effects of this utility model are as follows:

[0011] The purified water heat exchanger designed in this invention achieves effective heat recovery and utilization. This structure allows the phenol-removing wastewater to exchange heat with the purified water before entering the water tower, thereby lowering the temperature of the purified water and simultaneously raising the temperature of the phenol-removing wastewater. This not only reduces the cooling required for the subsequent cooling process of the purified water but also reduces the heat required to heat the phenol-removing wastewater, achieving efficient energy utilization and significantly reducing the overall energy consumption of the device.

[0012] This invention incorporates a first liquid level indicator and control alarm on the oil-water separator, electrically connected to a first liquid level control valve. This allows for real-time monitoring of liquid level changes within the oil-water separator, ensuring precise and controllable solvent overflow and reflux processes. This prevents solvent waste and spillage, while also guaranteeing the continuity and stability of solvent recovery.

[0013] This invention features a temperature indicator and control alarm installed on the solvent condensate pipe, which is electrically connected to a temperature control valve on the cooling water return pipe of the water tower top cooler. This allows for automatic adjustment of the cooling water flow rate based on the temperature of the solvent condensate, ensuring that the condensation effect is always optimal. This not only improves the solvent recovery efficiency but also guarantees the quality of the recovered solvent. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the structure of this utility model.

[0015] The components include: 1. Purified water heat exchanger; 2. Extraction and dephenolization wastewater conveying pipe; 3. Purified water conveying pump; 4. Water tower; 5. Water tower top cooler; 6. Temperature indicator and control alarm; 7. Oil-water separator; 8. First liquid level indicator and control alarm; 9. Reflux pump; 10. First liquid level control valve; 11. Purified water conveying pipe; 12. Second liquid level control valve; 13. Purified water cooler; 14. Solvent recovery tank; 15. Temperature control valve; and 16. Second liquid level indicator and control alarm. Detailed Implementation

[0016] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, but the present invention is not limited to the following embodiments.

[0017] exist Figure 1 In this embodiment, the solvent stripping device for treating semi-coke wastewater has the following components: the inlet A of the purified water heat exchanger 1 is connected to the extraction and dephenolization wastewater conveying pipe 2; the outlet A is connected to the extraction and dephenolization wastewater inlet of the water tower 4; the inlet B is connected to the purified water outlet at the bottom of the water tower 4 via the purified water conveying pump 3; the outlet B is connected to the inlet of the purified water cooler 13; and the outlet of the purified water cooler 13 is connected to the purified water conveying pipe 11.

[0018] Inside the purified water heat exchanger 1, the extracted phenol-removing wastewater transported by the extraction and phenol removal wastewater conveying pipe 2 exchanges heat with the purified water. The temperature of the output extracted phenol-removing wastewater increases while the temperature of the purified water decreases, realizing the recovery and utilization of the heat energy of the purified water and reducing the energy consumption of subsequent stripping. The purified water after heat exchange enters the purified water cooler to further reduce the water temperature, and is then transported to the subsequent wastewater treatment process through the purified water conveying pipe.

[0019] The preheated phenol-removing wastewater from the extraction process enters water tower 4, the core equipment for solvent stripping. The solvent exhaust port at the top of water tower 4 is connected to the inlet of the top cooler 5. Inside water tower 4, the solvent in the wastewater is vaporized through heating or steam injection. The solvent vapor exits from the top of water tower 4 and enters the top cooler 5, where cooling water condenses the solvent vapor into liquid. The solvent condensate outlet of the top cooler 5 is connected to the inlet of the oil-water separator 7 via a solvent condensate pipe. A temperature control valve 15 is installed on the cooling water return pipe of the top cooler 5, and a temperature indicator and alarm 6 is installed on the solvent condensate pipe. The temperature indicator and alarm 6 is electrically connected to the temperature control valve 15. The temperature indicator and alarm 6 monitors the temperature changes of the solvent condensate in real time. When the temperature is abnormal, the temperature control valve 15 automatically adjusts the cooling water flow rate to ensure optimal condensation.

[0020] The solvent overflow port of the oil-water separator 7 is connected to the solvent recovery tank 14, and the drain port is connected to the return port of the water tower 4 via the return pump 9. A first liquid level control valve 10 is installed on the outlet of the return pump 9, and a first liquid level indicator and control alarm 8 is installed on the oil-water separator 7. The first liquid level indicator and control alarm 8 is electrically connected to the first liquid level control valve 10. When the first liquid level indicator and control alarm 8 detects that the liquid level in the oil-water separator 7 reaches the preset high liquid level, the first liquid level control valve 10 automatically opens to discharge the liquid and prevent liquid overflow; when the liquid level drops to the preset low liquid level, the first liquid level control valve 10 automatically closes to stop discharging liquid and ensure that the liquid in the oil-water separator 7 is maintained within a safe liquid level range.

[0021] A second liquid level indicator and control alarm 16 is installed on the lower side of water tower 4, and a second liquid level control valve 12 is installed on the purified water delivery pipe 11. The second liquid level indicator and control alarm 16 is electrically connected to the second liquid level control valve 12. When the second liquid level indicator and control alarm 16 detects that the purified water level in water tower 4 reaches the preset high level, the opening of the second liquid level control valve 12 automatically increases to accelerate liquid discharge; when the liquid level drops to the preset low level, the second liquid level control valve 12 automatically closes to stop liquid discharge, ensuring that the purified water in water tower 4 is maintained within a safe liquid level range.

Claims

1. A solvent stripping device for treating semi-coke wastewater, comprising a water tower for stripping, characterized in that: The inlet A of the purified water heat exchanger is connected to the extraction and phenol removal wastewater conveying pipe, the outlet A is connected to the extraction and phenol removal wastewater inlet of the water tower, the inlet B is connected to the purified water outlet at the bottom of the water tower via a purified water conveying pump, the outlet B is connected to the purified water conveying pipe, the solvent exhaust port at the top of the water tower is connected to the air inlet of the water tower top cooler, the solvent condensate outlet of the water tower top cooler is connected to the feed port of the oil-water separator via a solvent condensate pipe, the solvent overflow port of the oil-water separator is connected to the solvent recovery tank, and the drain port is connected to the return port of the water tower via a return pump. A first liquid level control valve is installed on the outlet of the return pump, and a first liquid level indicator and control alarm is installed on the oil-water separator. The first liquid level indicator and control alarm is electrically connected to the first liquid level control valve. A temperature control valve is installed on the cooling water return pipe of the water tower top cooler, and a temperature indicator and control alarm is installed on the solvent condensate pipe. The temperature indicator and control alarm is electrically connected to the temperature control valve.

2. The solvent stripping device for treating semi-coke wastewater according to claim 1, characterized in that: A second liquid level indicator and control alarm is installed on the lower side of the water tower, and a second liquid level control valve is installed on the purified water delivery pipe. The second liquid level indicator and control alarm is electrically connected to the second liquid level control valve.

3. The solvent stripping device for treating semi-coke wastewater according to claim 1 or 2, characterized in that: A purified water cooler is connected to the purified water delivery pipe.

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