Skid-mounted ammonia-nitrogen wastewater treatment system

Abstract

The utility model discloses a skid-mounted ammonia nitrogen wastewater treatment system which comprises a feed pump, a preheater, a kettle liquid pump, an ammonia still, an ammonia water storage tank and an ammonia water pump, the input end of the feed pump is connected with a feed port, the output end of the feed pump is connected with a cold end inlet of the preheater through a pipeline, and a cold end outlet of the preheater is connected with the middle of the ammonia still through a pipeline. A kettle outlet of the ammonia still is connected with a kettle liquid pump through a pipeline, an outlet of the kettle liquid pump is connected with a hot end inlet of a preheater, a hot end outlet of the preheater is connected with a waste liquid discharge port, a middle liquid outlet of the ammonia still is connected with a top liquid inlet of an ammonia water storage tank, and a bottom liquid outlet of the ammonia water storage tank is connected with an ammonia water pump through a pipeline. The system provided by the utility model is arranged on the skid-mounted platform to play a role of convenience in installation, is compact in structural arrangement, short in construction period, flexible in installation and convenient to install, move and transport, preheats raw material liquid by utilizing redundant heat of ammonia distillation kettle liquid, and improves the heat utilization efficiency, so that the efficiency of the device is improved, and the operation energy consumption of the equipment is reduced.

Description

Technical Field

[0001] This utility model relates to the field of wastewater treatment, and in particular to a skid-mounted ammonia nitrogen wastewater treatment system. Background Technology

[0002] High-concentration ammonia nitrogen wastewater has a wide range of sources and is discharged in large quantities. Industries such as fertilizer production, coking, petrochemicals, pharmaceuticals, food processing, and landfills all generate large amounts of high-concentration ammonia nitrogen wastewater. Discharging this type of wastewater into water bodies not only causes eutrophication and blackening of the water, but also increases the difficulty and cost of water treatment, and may even have toxic effects on humans and other organisms. Therefore, researching technologies for reducing ammonia nitrogen wastewater discharge and its resource utilization is of great significance for the treatment and achieving compliant discharge of ammonia nitrogen wastewater.

[0003] Commonly used industrial methods for treating ammonia nitrogen wastewater include biological methods, chemical precipitation, breakpoint chlorination, ion exchange, membrane absorption, and stripping. Current research also includes the use of ammonia stripping towers to extract ammonia water from ammonia nitrogen wastewater. Ammonia stripping towers belong to the category of desorption towers and are devices that release free ammonia dissolved in the liquid phase through heat transfer via a heat carrier. Generally, steam is used as the heating agent, ensuring that the equilibrium vapor pressure of ammonia above the water surface is greater than the partial pressure of ammonia in the heat carrier. The vapor and liquid phases flow counter-currently, undergoing mass and heat transfer, thereby releasing ammonia from the liquid phase. A mixture of ammonia vapor and water vapor is obtained at the top of the tower, while a liquid phase with removed ammonia nitrogen is obtained at the bottom. Traditional ammonia stripping systems suffer from difficulty in completely condensing ammonia at the top of the tower, leading to pressure buildup and sometimes necessitating venting of ammonia, resulting in excessive emissions. Furthermore, the overall structure of ammonia stripping systems is complex, requiring a large area, and the installation process is complicated and cumbersome, posing a challenge to installation.

[0004] Therefore, this utility model proposes a skid-mounted ammonia nitrogen wastewater treatment system, which features a compact structure, short construction period, flexible installation, and easy installation and transportation. Utility Model Content

[0005] In view of the problems existing in the prior art, the purpose of this utility model is to provide a skid-mounted ammonia nitrogen wastewater treatment system to solve the problem that ammonia gas at the top of the ammonia stripping tower cannot be completely condensed, and to improve the shortcomings of traditional ammonia stripping systems, which have a complex overall structure and complicated installation and construction process.

[0006] To achieve the above objectives, this utility model provides the following technical solution:

[0007] A skid-mounted ammonia nitrogen wastewater treatment system includes a feed pump, a preheater, a bottom liquid pump, an ammonia stripping tower, an ammonia storage tank, and an ammonia pump. The feed pump's input end is connected to the feed inlet, and its output end is connected to the cold end inlet of the preheater via a pipeline. The cold end outlet of the preheater is connected to the middle section of the ammonia stripping tower via a pipeline. The bottom outlet of the ammonia stripping tower is connected to the bottom liquid pump via a pipeline, and the bottom liquid pump outlet is connected to the hot end inlet of the preheater. The hot end outlet of the preheater is connected to the waste liquid discharge outlet, the liquid outlet in the middle section of the ammonia stripping tower is connected to the top liquid inlet of the ammonia storage tank, and the liquid outlet at the bottom of the ammonia storage tank is connected to the ammonia pump via a pipeline.

[0008] Furthermore, the ammonia stripping tower is arranged from top to bottom as follows: a washing section, a condensation section, a rectification section, and a stripping section. The washing section is provided with a washing liquid inlet at the top and a washing liquid outlet at the bottom.

[0009] Furthermore, the condensation section is equipped with a condenser, and the rectification section and stripping section are combined, packed, or tray type.

[0010] Furthermore, the washing solution is pure water or an acidic liquid.

[0011] Furthermore, the lower part of the ammonia stripping tower is provided with a steam inlet.

[0012] Furthermore, it includes a skid-mounted platform on which the system is installed.

[0013] Compared with the prior art, the beneficial effects of this utility model are:

[0014] 1) The ammonia nitrogen wastewater generated during the production process of this utility model is preheated in the raw material preheater via a feed pump, and then enters the ammonia stripping tower after heat exchange. After entering the ammonia stripping tower, due to the higher volatility of ammonia than water, the ammonia in the wastewater is converted into a gaseous state under the action of steam. In the ammonia stripping tower, after multiple gas-liquid phase equilibrations, the ammonia concentration in the gas phase reaches the designed concentration requirement and enters the internal reflux condenser for liquefaction. Part of the liquefied ammonia water is transported as a product to the ammonia water storage tank, and part is returned to the ammonia stripping tower to participate in the gas-liquid phase equilibration again. As the ammonia in the liquid in the ammonia stripping tower continues to evaporate, the ammonia content in the liquid gradually decreases. When the ammonia content in the liquid meets environmental emission requirements, the liquid discharged from the ammonia stripping tower outlet passes through the raw material preheater and exchanges heat with the wastewater before entering the ammonia stripping tower. The effluent from the raw material preheater is then discharged. A washing section is installed at the top of the ammonia stripping tower to wash the gas that has not been completely condensed after passing through the condenser. The treated tail gas is discharged in compliance with standards.

[0015] 2) This utility model of skid-mounted ammonia nitrogen wastewater treatment system solves the problem of excessive emissions due to pressure build-up in the top condenser of conventional ammonia stripping tower by centrally arranging the washing section, condensing section, rectification section and stripping section in the ammonia stripping tower, thereby reducing the ammonia nitrogen content in the tail gas, making the overall layout of the skid compact, reducing the overall footprint of the wastewater treatment equipment, shortening the project construction period, and realizing the integrated layout of the ammonia stripping tower.

[0016] 3) The skid-mounted ammonia nitrogen wastewater treatment system of this utility model is set on a skid-mounted platform, which facilitates installation. The entire set of equipment is fully skid-mounted and can be installed simply by connecting it to the wastewater pipeline to be treated. The structure is compact, with a short construction period, flexible installation, and easy installation and transportation. It utilizes the excess heat of the ammonia stripping kettle liquid to preheat the raw material liquid, thereby improving the heat utilization efficiency, improving the efficiency of the equipment, and reducing the energy consumption of equipment operation. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the overall system structure of this utility model.

[0018] In the diagram: 1. Feed pump; 2. Preheater; 3. Kettle liquid pump; 4. Ammonia stripping tower; 5. Ammonia water storage tank; 6. Ammonia water pump; A. Ammonia nitrogen-containing wastewater; B. Water vapor; C. Ammonia removal wastewater; D. Circulating water; E. Washing liquid; F. Tail gas. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but the scope of protection of the present invention is not limited to the scope described.

[0020] Please refer to Figure 1 A skid-mounted ammonia nitrogen wastewater treatment system includes a feed pump 1, a preheater 2, a bottom liquid pump 3, an ammonia stripping tower 4, an ammonia water storage tank 5, and an ammonia water pump 6. The input end of the feed pump 1 is connected to the feed inlet, and the output end of the feed pump 1 is connected to the cold end inlet of the preheater 2 through a pipeline. The cold end outlet of the preheater 2 is connected to the middle part of the ammonia stripping tower 4 through a pipeline. The bottom outlet of the ammonia stripping tower 4 is connected to the bottom liquid pump 3 through a pipeline. The outlet of the bottom liquid pump 3 is connected to the hot end inlet of the preheater 2. The hot end outlet of the preheater 2 is connected to the waste liquid discharge outlet, and the ammonia removal wastewater C is discharged from the hot end outlet of the preheater 2. The liquid outlet in the middle part of the ammonia stripping tower 4 is connected to the top liquid inlet of the ammonia water storage tank 5, and the liquid outlet at the bottom of the ammonia water storage tank 5 is connected to the ammonia water pump 6 through a pipeline.

[0021] The ammonia stripping tower 4 is arranged from top to bottom as follows: a washing section, a condensation section, a rectification section, and a stripping section. The washing section is provided with a washing liquid inlet at the top and a washing liquid outlet at the bottom.

[0022] The condensation section is equipped with a condenser and circulating water D. The rectification section and stripping section are combined, packed, or tray type.

[0023] In this embodiment, the washing liquid E is pure water or an acidic liquid.

[0024] The lower part of the ammonia stripping tower 4 is equipped with a steam inlet, and steam B provides a heat source for the ammonia stripping tower.

[0025] In this embodiment, a skid-mounted platform is included. The system of this utility model is installed on the skid-mounted platform, which makes the equipment convenient for transportation, handling and installation.

[0026] This utility model describes a method for treating ammonia nitrogen wastewater using a skid-mounted ammonia nitrogen wastewater treatment system, comprising the following steps:

[0027] First, the ammonia-containing wastewater A generated during the production process enters the raw material preheater 2 via feed pump 1 for preheating. After heat exchange, it enters the ammonia stripping tower 4. Upon entering the ammonia stripping tower 4, due to the higher volatility of ammonia compared to water, the ammonia in the wastewater is converted into a gaseous state under the action of water vapor B. In the ammonia stripping tower 4, after multiple gas-liquid phase equilibrations, the ammonia concentration in the gas phase reaches the designed concentration requirement and enters the internal reflux condenser for liquefaction. Part of the liquefied ammonia water is transported as product to the ammonia water storage tank 5, and the remaining part... The liquid is returned to the ammonia stripping tower 4 and participates in the gas-liquid phase balance again. As the ammonia evaporates, the ammonia content in the liquid in the ammonia stripping tower 4 gradually decreases. When the ammonia content in the liquid meets the environmental emission requirements, the liquid discharged from the outlet of the ammonia stripping tower 4 passes through the raw material preheater 2 and exchanges heat with the wastewater before entering the ammonia stripping tower 4. The water from the raw material preheater 2 is discharged. A washing section is set at the top of the ammonia stripping tower 4 to wash the gas that has not been completely condensed after passing through the condenser. The treated tail gas F is discharged in compliance with standards. Example 1

[0028] The wastewater treatment system provided in Example 1 is used to treat ammonia nitrogen wastewater discharged by a certain enterprise. The treatment method specifically includes the following steps:

[0029] The ammonia nitrogen content in the wastewater generated during the production process is 1000~2000 mg / L, and the wastewater is discharged at a concentration of 60 m³ / L. 3 The wastewater flows into feed pump 1 at a flow rate of / d. Feed pump 1 sends the wastewater into preheater 2, where the temperature is raised to 99℃, and then into ammonia stripping tower 4. Steam at a pressure of 0.5MPa enters ammonia stripping tower 4 through the steam inlet and comes into countercurrent contact with the wastewater at the packing, causing the ammonia in the wastewater to enter the gas phase. After multiple gas-liquid phase equilibriums, the ammonia vapor enters the condensation section for condensation. The ammonia water, which is cooled to 55℃, is partly transported as a product to ammonia water storage tank 5 and partly returned to ammonia stripping tower 4 to participate in the gas-liquid phase equilibrium in the tower again.

[0030] Wastewater at 100℃ from the bottom of ammonia stripping tower 4 is pumped into preheater 2 via bottom liquid pump 3 to exchange heat with the feed wastewater. After the temperature drops to 35℃, the wastewater is discharged after testing to ensure it meets emission standards. Incompletely condensed steam from the condensation section enters the washing section for washing treatment. The treated exhaust gas meets emission standards. After wastewater treatment, the ammonia concentration and ammonia nitrogen content in the treated wastewater are tested. The product ammonia concentration is 10%, and the ammonia nitrogen content in the treated wastewater is 14 mg / L, with an ammonia recovery rate of 99%.

Claims

1. A skid-mounted ammonia nitrogen wastewater treatment system, characterized in that... The system includes a feed pump (1), a preheater (2), a bottom liquid pump (3), an ammonia stripping tower (4), an ammonia storage tank (5), and an ammonia pump (6). The feed pump (1) has its input end connected to the feed inlet. The feed pump (1) has its output end connected to the cold end inlet of the preheater (2) via a pipeline. The cold end outlet of the preheater (2) is connected to the middle of the ammonia stripping tower (4) via a pipeline. The bottom outlet of the ammonia stripping tower (4) is connected to the bottom liquid pump (3) via a pipeline. The outlet of the bottom liquid pump (3) is connected to the hot end inlet of the preheater (2). The hot end outlet of the preheater (2) is connected to the waste liquid discharge outlet. The liquid outlet in the middle of the ammonia stripping tower (4) is connected to the top liquid inlet of the ammonia storage tank (5). The liquid outlet at the bottom of the ammonia storage tank (5) is connected to the ammonia pump (6) via a pipeline.

2. The skid-mounted ammonia nitrogen wastewater treatment system according to claim 1, characterized in that... The ammonia stripping tower (4) is arranged from top to bottom as a washing section, a condensing section, a rectification section and a stripping section. The washing section is provided with a washing liquid inlet at the top and a washing liquid outlet at the bottom.

3. The skid-mounted ammonia nitrogen wastewater treatment system according to claim 2, characterized in that... The condensation section is equipped with a condenser, and the rectification section and stripping section are combined, packed, or tray type.

4. The skid-mounted ammonia nitrogen wastewater treatment system according to claim 2, characterized in that... The washing solution is pure water or an acidic liquid.

5. A skid-mounted ammonia nitrogen wastewater treatment system according to claim 2, characterized in that... The ammonia stripping tower (4) is equipped with a steam inlet at the bottom.

6. A skid-mounted ammonia nitrogen wastewater treatment system according to claim 2, characterized in that... Includes a skid-mounted platform, on which the system is installed.

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