Device for removing ammonia nitrogen in high-salinity wastewater

Abstract

The utility model relates to a device for removing ammonia nitrogen in high-salinity wastewater. The device comprises a buffer tank, a raw material conveying pump, a raw material preheater, a concentration tower I, a concentration tower II and a concentration tower III which are connected in sequence, tower kettles of the concentration tower I, the concentration tower II and the concentration tower III are respectively connected with corresponding reboilers and tower kettle liquid delivery pumps, and tower tops of the concentration tower I, the concentration tower II and the concentration tower III are respectively connected with corresponding tower top liquid reflux tanks, tower top reflux pumps and tower top coolers; and the tower top liquid return tanks of the concentration tower II and the concentration tower III are respectively connected with corresponding deep coolers. According to the device, three-tower triple-effect differential pressure thermal coupling rectification is adopted, ammonia nitrogen in the high-salinity wastewater is effectively removed, all effective components are recycled, purified water at the top of each tower can be used for preparing 20 (wt)% of ammonia water, and concentrated liquid at the bottom of the tower can be used for refining saline water in the chlor-alkali chemical industry; the tower top steam of the concentration tower I can be used as a heat source of the concentration tower II, and the tower top steam of the concentration tower II can be used as a heat source of the concentration tower III, so that the steam consumption is greatly reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of high-salt wastewater treatment in chemical production, and particularly relates to a device for removing ammonia nitrogen in high-salt wastewater. BACKGROUND

[0002] In the basic chemical industry, most enterprises have realized the "chlor-alkali coal-electricity" integrated circular economy mode. Chlor-alkali chemical industry and coal chemical industry will produce a large amount of high-salt wastewater in the production process. The ammonia nitrogen content in this part of high-salt water is usually high. In industrial production, the traditional high-salt wastewater is usually treated by incineration or evaporation crystallization technology. The produced salt is classified as hazardous waste, and there are difficulties in sales, which makes the treatment of high-salt wastewater only investment without output, resulting in an increase in unit cost and a great burden on enterprises. Therefore, in order to perfect the circular economy industry chain, it is necessary to invent a device for removing ammonia nitrogen in high-salt wastewater, so that the high-salt water after removing ammonia nitrogen can be used for chlor-alkali chemical industry brine refining, and the removed ammonia nitrogen can be used for producing ammonia water.

[0003] Chinese patent CN 215559109 U proposes a salt-containing waste liquid concentration crystallization system, which comprises a concentration device, a first partition wall type heat exchanger, a compressor and an evaporation crystallization device. The original waste liquid inlet of the concentration device is used to receive salt-containing waste liquid. The concentration waste liquid outlet of the concentration device is connected with the heat absorption medium inlet of the first partition wall type heat exchanger. The heat absorption medium outlet of the first partition wall type heat exchanger is respectively connected with the heat release medium inlet of the concentration device and the waste liquid inlet of the evaporation crystallization device. The steam outlet of the concentration device is connected with the steam inlet of the compressor. The steam outlet of the compressor is connected with the heat release medium inlet of the first partition wall type heat exchanger. The heat release medium outlet of the first partition wall type heat exchanger is used to output steam. The salt-containing waste liquid concentration crystallization system can reduce the discharge amount of environmental pollutants, improve energy utilization rate, and reduce the operation cost of the salt-containing waste liquid concentration crystallization system. However, the salt-containing waste liquid concentration crystallization system cannot be used to treat wastewater containing organic matter.

[0004] Chinese patent CN 217479269 U discloses a caprolactam containing NH4+ waste liquid resource treatment device, which comprises a reaction kettle connected with a caprolactam device, an ammonia evaporation tower connected with the reaction kettle, an ammonia absorption tower and a concentration tower connected with the ammonia evaporation tower, respectively, the ammonia absorption tower is connected with a sulfur ammonium crystallization system, and the concentration tower is connected with a sewage biochemical treatment device and a incineration device, respectively. In the caprolactam containing NH4+ waste liquid resource treatment device, the waste liquid is concentrated by using negative pressure double-effect tower, which is simple in process and convenient to operate, but the steam consumption is large, which is not ideal in energy saving. UTILITY MODEL CONTENTS

[0005] The device for removing ammonia nitrogen in high-salt wastewater is provided.

[0006] The device for removing ammonia nitrogen in high-salt wastewater is provided.

[0007] The concentration tower I and the concentration tower II are packed towers, and the upper section of the concentration tower III is a packed tower, and the lower section is a plate tower.

[0008] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0009] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0010] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0011] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0012] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0013] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler.

[0014] Compared with the prior art, the device for removing ammonia nitrogen in high-salt wastewater has the advantages that:

[0015] The tower kettle of the concentration tower I, the concentration tower II and the concentration tower III is respectively connected with a corresponding reboiler and a tower kettle liquid conveying pump, and the top of the tower is respectively connected with a corresponding tower top liquid reflux tank, a tower top reflux pump and a tower top cooler. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The device for removing ammonia nitrogen in high-salt wastewater is provided.

[0017] Figure 1In the figure, 1 is a concentration column I, 2A is a concentration column I reboiler, 2B is a concentration column II reboiler, 2C is a concentration column III reboiler, 3 is a raw material preheater, 4 is a concentration column I column still liquid cooler, 5A is a concentration column I column still liquid delivery pump, 5B is a concentration column II column still liquid delivery pump, 5C is a concentration column III column still liquid delivery pump, 6A is a concentration column I overhead reflux pump, 6B is a concentration column II overhead reflux pump, 6C is a concentration column III overhead reflux pump, 7A is a concentration column I overhead liquid reflux tank, 7B is a concentration column II overhead liquid reflux tank, 7C is a concentration column III overhead liquid reflux tank, 8 is a concentration column II, 9 is a column still circulating pump, 10A is a concentration column I overhead cooler, 10B is a concentration column II overhead cooler, 10C is a concentration column III overhead cooler, 11 is a concentration column III, 12 is a cryogenic cooler, 13 is an evaporation condenser, 14 is a raw material delivery pump, 15 is a buffer tank, and 16 is a cooling separator. DETAILED DESCRIPTION

[0018] Refer to the drawings Figure 1 The device for removing ammonia nitrogen in high-salinity wastewater provided by the embodiment of the present application comprises a buffer tank, a raw material delivery pump, a raw material preheater, a concentration column I, a concentration column II and a concentration column III connected in sequence.

[0019] Another embodiment is different in that the column stills of the concentration column I, the concentration column II and the concentration column III are respectively connected with corresponding reboilers and column still liquid delivery pumps, and the column tops are respectively connected with corresponding overhead liquid reflux tanks, overhead reflux pumps and overhead coolers.

[0020] Another embodiment is different in that the concentration column I column still is provided with a column still liquid cooler.

[0021] Another embodiment is different in that the column stills of the concentration column II and the concentration column III are respectively connected with corresponding column still circulating pumps.

[0022] Another embodiment is different in that the concentration column II and the concentration column III overhead liquid reflux tanks are respectively connected with corresponding cryogenic coolers.

[0023] Another embodiment is different in that the concentration column III column top is also connected with an evaporation condenser, and the evaporation condenser and the concentration column III overhead cooler are connected in series or in parallel.

[0024] The concentration column I, the concentration column II and the concentration column III column tops are each provided with a venting pipeline connected with a cooling separator, and ammonia gas in the column top gas is cooled and separated for recycling for ammonia water preparation.

[0025] The device for removing ammonia nitrogen in high-salinity wastewater described above specifically comprises the following process steps:

[0026] ①The high-salt wastewater with 1000-1500mg / L of ammonia nitrogen content, 8-10(wt)% of salt content and PH of 10-11 from outside is stabilized by a buffer tank, and then is pumped to 0.4-0.6MPaG by a raw material delivery pump, and is preheated by a raw material preheater after sequentially passing through a condensing tower III overhead cooler, a condensing tower II overhead cooler, a condensing tower I overhead cooler, a condensing tower I kettle liquid cooler, and is sent to the lower part of the condensing tower I, and is heated by a condensing tower I reboiler, and the rising vapor and the descending liquid are fully contacted to realize the separation of water and heavy components, and the condensing tower I kettle temperature is controlled at 100-110℃; the condensing tower I overhead pressure is controlled at 10-50kPaG; the condensing tower I overhead vapor is used as the heat source of the condensing tower II reboiler, and the condensing tower II kettle liquid is heated while the condensing tower I overhead vapor is condensed; the condensed liquid enters a condensing tower I overhead liquid reflux tank, and is pressurized to 0.3-0.5MPaG by a condensing tower I overhead reflux pump, and then a part of the condensed liquid is sent to the condensing tower I overhead reflux to the tower, and the other part of the condensed liquid is cooled to 35-45℃ by a condensing tower I overhead cooler, and then is sent to an ammonia water preparation section outside for recycling;

[0027] ②The condensing tower I kettle liquid is cooled by a condensing tower I kettle liquid cooler, and is sent to the lower part of the condensing tower II by a condensing tower I kettle liquid delivery pump, and is heated by a condensing tower II reboiler, and the heat source of the condensing tower II reboiler is provided by the condensing tower I overhead vapor, and the condensing tower II kettle temperature is controlled at 80-90℃; the condensing tower III overhead pressure is controlled at -60--20kPaG; the condensing tower II overhead vapor is used as the heat source of the condensing tower III reboiler, and the condensing tower III kettle liquid is heated while the condensing tower II overhead vapor is condensed; the condensed liquid enters a condensing tower II overhead liquid reflux tank, and is pressurized to 0.3-0.5MPaG by a condensing tower II overhead reflux pump, and then a part of the condensed liquid is sent to the condensing tower II overhead reflux to the tower, and the other part of the condensed liquid is cooled to 35-45℃ by a condensing tower II overhead cooler, and then is sent to an ammonia water preparation section outside for recycling; the uncondensed gas in the condensing tower II overhead liquid reflux tank is condensed by a deep cooler, and the gas that has not been condensed is sent to a vacuum system;

[0028] ③The condensing tower II kettle liquid is sent to the middle part of the condensing tower III by a condensing tower II kettle liquid delivery pump, and is heated by a condensing tower III reboiler, and the heat source of the condensing tower III reboiler is provided by the condensing tower II overhead vapor, and the condensing tower III kettle temperature is controlled at 55-65℃; the condensing tower III overhead pressure is controlled at -110--90kPaG; the condensing tower III overhead vapor is condensed in a condensing tower III overhead cooler and an evaporation condenser, and the uncondensed gas is further condensed by a deep cooler, and the gas that has not been condensed is sent to a vacuum system; the condensed liquid of the condensing tower III overhead cooler, the evaporation condenser and the deep cooler enters a condensing tower III overhead liquid reflux tank, and is pressurized to 0.3-0.5MPaG by a condensing tower III overhead reflux pump, and then a part of the condensed liquid is sent to the condensing tower III overhead reflux to the tower, and the other part of the condensed liquid is sent to outside for recycling; the condensing tower III kettle liquid is sent to a chlor-alkali chemical brine refining section by a condensing tower III kettle liquid delivery pump.

[0029] Another embodiment differs in that the ammonia nitrogen content in the concentrated column III column liquid is ≤5 mg / L.

[0030] Another embodiment differs in that the concentrated column III column liquid contains 25-28 (wt) % salt.

[0031] Another embodiment differs in that the concentrated column III column liquid PH is 6-8.

[0032] Another embodiment differs in that the concentrated column I reboiler heat is provided by 0.4-2.0 MPaG steam.

[0033] The above only the preferred embodiment of the present application, and not to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application, should be included within the scope of the present application.

Claims

1. A device for removing ammonia nitrogen from high-salinity wastewater, characterized in that: The concentration column I, the concentration column II and the concentration column III are connected with corresponding reboilers and column liquid delivery pumps respectively, and the column tops are connected with corresponding column top liquid reflux tanks, column top reflux pumps and column top coolers respectively. The concentration column I, the concentration column II and the concentration column III are connected with corresponding reboilers and column liquid delivery pumps respectively, and the column tops are connected with corresponding column top liquid reflux tanks, column top reflux pumps and column top coolers respectively. The concentration column II and the concentration column III are connected with corresponding deep coolers respectively.

2. The device for removing ammonia nitrogen in high-salinity wastewater according to claim 1, characterized in that: The concentration column I is provided with a column liquid cooler.

3. The device for removing ammonia nitrogen in high-salinity wastewater according to claim 1, characterized in that: The concentration column III is connected with an evaporation condenser, and the evaporation condenser and the concentration column III are connected in series or in parallel.

4. The device for removing ammonia nitrogen in high-salinity wastewater according to claim 1, characterized in that: The concentration column II and the concentration column III are connected with corresponding column circulating pumps respectively.

5. The device for removing ammonia nitrogen in high-salinity wastewater according to claim 1, characterized in that: The concentration column I and the concentration column II are packed columns, and the upper section of the concentration column III is a packed column and the lower section is a plate column.

6. The device for removing ammonia nitrogen in high-salinity wastewater according to claim 1, characterized in that: The concentration column I, the concentration column II and the concentration column III are each provided with a vent line connected with a cooling separator.

Images