Dilute nitric acid concentration device

Abstract

The utility model provides a dilute nitric acid concentration device. The dilute nitric acid concentration device comprises a concentration tower, a reboiler, a condenser, a wastewater intermediate tank, a reflux delivery pump and a circulating pump, the lower part of the concentration tower is connected with a reboiler in parallel, an outlet in the upper part of the reboiler is connected with a gas inlet in the middle and lower part of the concentration tower, and an inlet in the lower part of the reboiler is connected with a discharge hole in the lower part of the concentration tower; a top outlet of the concentration tower is connected with a side feed port of the condenser, a top inlet of the condenser is connected with an outlet of the circulating pump, a bottom outlet of the condenser is connected with an upper inlet of the wastewater intermediate tank, and a waste gas port is formed in the middle lower part of the condenser and is connected with a waste gas pipeline; and a bottom outlet of the wastewater intermediate tank is respectively connected with inlets of the reflux delivery pump and the circulating pump. According to the device, the waste liquid with the nitric acid content of about 10% is concentrated into dilute nitric acid with the nitric acid content of more than 30% to realize in-situ application, automatic operation is realized through interlocking control, and the device has the advantages of low energy consumption, high acid recovery rate, stable operation and the like.

Description

TECHNICAL FIELD

[0001] The utility model relates to the field of pharmaceutical chemical industry and environmental protection, concretely relates to a dilute nitric acid concentration production device. BACKGROUND

[0002] In the production process of pharmaceutical intermediates and the treatment of nitrogen oxide-containing waste gas by water absorption technology, dilute nitric acid waste liquid with a nitric acid content of 5-10% is produced. Such waste liquid has certain economic value and the nitric acid therein can be recovered. CN221440395U discloses a device for recovering nitric acid from dilute nitric acid waste liquid. The device is suitable for treating acid waste liquid containing reaction intermediates and focuses on removing organic impurities and salt impurities such as waste catalysts. The device first dehydrates and concentrates the waste liquid, and then performs azeotropic distillation to obtain 30% dilute nitric acid. The organic impurities are recovered as waste residue and treated separately. The device is complex, has high investment and high recovery cost. However, for the recovery and treatment of nitric acid in dilute nitric acid waste liquid that can utilize organic impurities in situ and has no high-freezing-point organic matter and salt impurities, a production device with low investment, low cost and high automation is needed. SUMMARY

[0003] To solve the above problems, the present application discloses a dilute nitric acid concentration device, which can enrich dilute nitric acid from a mass concentration of 5-10% to a mass concentration of more than 30%, while preserving the organic matter from being destroyed and recovering the nitric acid for in-situ reuse. The device has the characteristics of low energy consumption, high nitric acid recovery rate, high automation and no secondary pollution.

[0004] A dilute nitric acid concentration device, comprising a concentration tower, a reboiler, a condenser, a waste water intermediate tank, a reflux liquid delivery pump and a circulating pump. The middle part of the concentration tower is provided with a feed inlet, which is connected with a feed pipeline. The lower part of the concentration tower is connected in parallel with the reboiler. The upper outlet of the reboiler is connected with the gas inlet of the middle or lower part of the concentration tower. The lower inlet of the reboiler is connected with the lower outlet of the concentration tower. The top outlet of the concentration tower is connected with the side feed inlet of the condenser. The top inlet of the condenser is connected with the outlet of the circulating pump. The bottom outlet of the condenser is connected with the upper inlet of the waste water intermediate tank. The middle or lower part of the condenser is provided with a waste gas outlet, which is connected with a waste gas pipeline. The bottom outlet of the waste water intermediate tank is connected with the inlets of the reflux liquid delivery pump and the circulating pump. The reflux liquid delivery pump has two outlets, one of which is connected with the upper inlet of the concentration tower, and the other is connected with the top inlet of the waste water intermediate tank. The circulating pump has two outlets, one of which is connected with the top inlet of the condenser, and the other outlet sends the excess condensate to a waste water treatment device.

[0005] Further, a flow meter and a feed flow regulating valve are arranged on the feed pipe of the concentration tower, and the flow meter controls the opening degree of the feed flow regulating valve through a transmitter.

[0006] Further, a pressure gauge and a steam flow regulating valve are arranged on the heating steam inlet pipe of the reboiler, and the pressure gauge controls the opening degree of the steam flow regulating valve through a transmitter.

[0007] Further, a liquid level meter is arranged at the lower part of the concentration tower, and a tower bottom outlet regulating valve is arranged on the outlet pipe, and the liquid level meter controls the opening degree of the regulating valve through a transmitter.

[0008] Further, a flow meter and a reflux liquid flow regulating valve are arranged on the reflux liquid pipe of the concentration tower, and the flow meter controls the opening degree of the reflux liquid flow regulating valve through a transmitter.

[0009] Further, a liquid level meter is arranged on the side of the wastewater intermediate tank, and a wastewater intermediate tank liquid level regulating valve is arranged on the pipe through which the circulating pump transports wastewater to the wastewater treatment device, and the liquid level meter controls the opening degree of the wastewater intermediate tank liquid level regulating valve through a transmitter.

[0010] Further, the concentration tower is a packed tower, and the packing is ceramic structured packing.

[0011] The device separates the nitric acid waste liquid with a concentration of 5-10% in the concentration tower, collects condensed water from the top of the tower, collects 30-32% of recovered nitric acid from the bottom of the tower, and sends the trace nitric acid in the condensed water to a wastewater treatment station, and the recovered nitric acid is used in situ to the acid production device for acid mixing.

[0012] The device has the advantages that the dilute nitric acid is enriched from a mass concentration of 5-10% to a mass concentration of more than 30%, in-situ reuse is realized, the device has low energy consumption, high nitric acid recovery rate, and high automation degree BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 The utility model discloses a structure schematic diagram;

[0014] The utility model discloses a structure schematic diagram;

[0015] 1-concentration tower;2- feed flow regulating valve;3- steam flow regulating valve;4- reboiler;5- reflux liquid flow regulating valve;6- condenser;7- wastewater intermediate tank;8- reflux liquid delivery pump;9- circulating pump;10- wastewater intermediate tank liquid level regulating valve;11- tower bottom outlet regulating valve;12- feed pipe;13- heating steam inlet pipe. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be understood that the following specific embodiments are intended only to illustrate the present invention and are not intended to limit the scope of the present invention. It should be noted that the terms "front," "rear," "left," "right," "up," and "down" used in the following description refer to directions in the accompanying drawings, and the terms "inward" and "outward" refer to directions toward or away from the geometric center of a particular component, respectively.

[0017] like Figure 1 As shown, a dilute nitric acid concentration device of this embodiment includes a concentration tower 1, a reboiler 4, a condenser 6, a wastewater intermediate tank 7, a reflux liquid delivery pump 8 and a circulation pump 9; a feed port is provided in the middle of the concentration tower 1, and the feed port is connected to the feed pipe 12; the concentration tower 1 is a packed tower, and the packing is a ceramic structured packing; a pressure gauge is provided at the top of the concentration tower 1, and thermometers are provided at the top, middle and bottom respectively, and all temperature, pressure and regulating valve opening signals are connected to the DCS system.

[0018] The feed pipe 12 of concentrator 1 is equipped with a flowmeter and feed flow control valve 2. The flowmeter controls the valve opening via a transmitter. A liquid level gauge is located at the bottom of concentrator 1, and a kettle extraction control valve 11 is located on the bottom outlet pipe. The level gauge controls the flow control valve opening via a transmitter. The reflux pipe of concentrator 1 is equipped with a flowmeter and reflux flow control valve 5. The flowmeter controls the valve opening via a transmitter.

[0019] A reboiler 4 is connected in parallel to the lower portion of the concentrator 1. The upper outlet of reboiler 4 is connected to the air inlet at the lower center of the concentrator 1, while the lower inlet of reboiler 4 is connected to the lower discharge port of the concentrator 1. The top outlet of the concentrator 1 is connected to the side feed port of the condenser 6. A pressure gauge and steam flow control valve 3 are installed on the heating steam inlet pipe 13 of the reboiler 4. The pressure gauge controls the opening of the control valve via a transmitter.

[0020] The top inlet of the condenser 6 is connected to the outlet of the circulation pump 9, and the bottom outlet of the condenser 6 is connected to the upper inlet of the wastewater intermediate tank 7. The lower part of the condenser 6 is provided with an exhaust port connected to the exhaust pipe; the bottom outlet of the wastewater intermediate tank 7 is connected to the inlet of the reflux liquid delivery pump 8 and the circulation pump 9 respectively.

[0021] The reflux liquid delivery pump 8 has two outlets, one of which is connected to the upper inlet of the concentration tower 1, and the other outlet is connected to the top inlet of the wastewater intermediate tank 7. The circulation pump 9 has two outlets, one of which is connected to the top inlet of the condenser 6, and the other outlet delivers excess condensate to the wastewater treatment device.

[0022] The liquid level meter is arranged on the side of the wastewater intermediate tank 7, and the wastewater intermediate tank liquid level regulating valve 10 is arranged on the pipeline for conveying the wastewater to the wastewater treatment device by the circulating pump 9; the liquid level meter controls the opening degree of the wastewater intermediate tank liquid level regulating valve 10 through the transmitter.

[0023] The operation example of the device is as follows:

[0024] 1. First, fill the wastewater intermediate tank to 50% of the liquid level, start the circulating pump to realize the system circulation of the condenser-wastewater intermediate tank-circulating pump, and open the inlet and outlet water of the condenser. Place the feed flow regulating valve in the manual position, slowly open the feed flow regulating valve to feed the middle part of the concentration tower (10% dilute nitric acid waste liquid). When the liquid level of the concentration tower reaches 65-70%, close the feed regulating valve, stop feeding, and start the temperature rising operation.

[0025] 2. Place the steam flow regulating valve in the manual position, slowly open the steam inlet valve to feed the reboiler with steam for heating. Slowly increase the opening degree of the steam regulating valve manually, and gradually increase the temperature of the tower kettle until boiling. As evaporation proceeds, the liquid level of the concentration tower gradually decreases, and the feed is supplemented in time to maintain the liquid level of the tower kettle at 40-65%. The temperature at each point in the tower continues to rise. When the temperature at the top of the concentration tower rises to about 90℃, perform the reflux operation.

[0026] 3, the concentrated tower overhead reflux liquid flow regulating valve is placed in the manual closed position, the reflux liquid delivery pump is started, the regulating valve is slowly opened, the regulating valve opening is slowly increased according to the wastewater intermediate tank liquid level change, the liquid level is kept basically unchanged, and the concentration tower is in full reflux evaporation state. With the full reflux evaporation, the tower top temperature has the process of rising and falling again, when the tower top temperature rises and falls to 100±1℃ interval, the reflux liquid flow is stabilized at about 550kg / h, the sampling analysis tower top production liquid nitric acid concentration is taken; when the nitric acid content is less than 0.5%, the reflux flow is kept unchanged, and the tower top production is started. After the tower top has production, the tower kettle temperature and liquid level in full reflux operation are gradually increased. When the kettle temperature rises to 107~108℃, the kettle liquid is discharged into the recovered nitric acid tank by opening the tower bottom production regulating valve, the concentrated tower kettle liquid level control loop is set to 50%, the liquid level regulating valve is placed in the automatic position, and the device enters stable operation. The feed flow regulating valve is changed to automatic control, the control loop is set to 1550kg / h to realize stable continuous feeding; the reflux liquid flow control loop is set to 550kg / h; the reboiler steam regulating valve is changed to automatic control, the control loop is set to 0.4MPa, the reboiler realizes stable heating, and the kettle temperature is maintained at 107~108℃; the wastewater intermediate tank liquid level regulating valve is opened, and the wastewater intermediate tank liquid level control loop is set to 60%, and the liquid level regulating valve is placed in the automatic position. The excess wastewater is sent to the wastewater treatment system for centralized treatment. The nitric acid concentration of the tower top production liquid and the kettle production liquid is sampled and analyzed at regular intervals, and the set value of the heating steam pressure control loop is adjusted in time according to the analysis result, so that the nitric acid content of the tower top production liquid is ≤0.5%, and the nitric acid content of the kettle production liquid is ≥32%. After the device enters stable operation, all process parameters can be remotely controlled in the DCS system.

[0027] The technical means disclosed in the scheme of the application is not limited to the technical means disclosed in the above-mentioned embodiments, and also includes technical solutions composed of any combination of the above technical features.

Claims

1. A dilute nitric acid concentration plant comprising a concentration column (1), characterized in that: The condensing tower (1) is provided with a feed inlet in the middle part, the feed inlet is connected with a feed pipeline (12); the lower part of the condensing tower (1) is connected with a reboiler (4), the upper outlet of the reboiler (4) is connected with the air inlet in the middle and lower part of the condensing tower (1), the lower inlet of the reboiler (4) is connected with the lower outlet of the condensing tower (1); the top outlet of the condensing tower (1) is connected with the side feed inlet of a condenser (6), the top inlet of the condenser (6) is connected with the outlet of a circulating pump (9), the bottom outlet of the condenser (6) is connected with the upper inlet of a waste water intermediate tank (7), the middle and lower part of the condenser (6) is provided with a waste gas outlet connected with a waste gas pipeline; the bottom outlet of the waste water intermediate tank (7) is connected with the inlets of the reflux liquid conveying pump (8) and the circulating pump (9) respectively; the reflux liquid conveying pump (8) has two outlets, one of which is connected with the upper inlet of the condensing tower (1), and the other outlet is connected with the top inlet of the waste water intermediate tank (7); the circulating pump (9) has two outlets, one of which is connected with the top inlet of the condenser (6), and the other outlet sends the excess condensate to a waste water treatment device.

2. A dilute nitric acid concentration device according to claim 1, characterized in that: The feed pipeline (12) of the condensing tower (1) is provided with a flow meter and a feed flow adjusting valve (2).

3. The dilute nitric acid concentration device according to claim 1, characterized in that: The heating steam inlet pipeline (13) of the reboiler (4) is provided with a pressure gauge and a steam flow adjusting valve (3).

4. The dilute nitric acid concentration device according to claim 1, characterized by: The lower part of the condensing tower (1) is provided with a liquid level meter, and the bottom outlet pipeline is provided with a tower kettle production adjusting valve (11).

5. The dilute nitric acid concentration device according to claim 1, characterized in that: The reflux liquid pipeline of the condensing tower (1) is provided with a flow meter and a reflux liquid flow adjusting valve (5).

6. The dilute nitric acid concentration device according to claim 1, characterized by: The side of the waste water intermediate tank (7) is provided with a liquid level meter, and the pipeline from the circulating pump (9) to the waste water treatment device is provided with a waste water intermediate tank liquid level adjusting valve (10).

7. The dilute nitric acid concentration device according to claim 1, characterized by: The condensing tower (1) is a packed tower, and the packing is ceramic structured packing.

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