CN218249418U - Nitrous gas recovery unit - Google Patents
Nitrous gas recovery unit Download PDFInfo
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- CN218249418U CN218249418U CN202222266731.3U CN202222266731U CN218249418U CN 218249418 U CN218249418 U CN 218249418U CN 202222266731 U CN202222266731 U CN 202222266731U CN 218249418 U CN218249418 U CN 218249418U
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Abstract
The utility model provides a nitrous gas recovery unit, including liquid ring compressor, it is first, the second absorption tower, liquid ring compressor's gas vent links to each other with the lateral wall bottom of first absorption tower through first pipeline, first absorption tower is the packed tower, from last down the interval set up first, the second, the third packs the absorption section, and be provided with corresponding backflow pipeline respectively, the quantity of second absorption tower is one or more, constitute wholly through establishing ties, the gaseous phase import of second absorption tower links to each other through the top of the second pipeline with first absorption tower. The utility model has the advantages of being simple in structure and convenient in operation, but low-cost, high efficiency recycle nitrous gas, nitrous gas in especially tail gas, and satisfy the environmental protection requirement.
Description
Technical Field
The utility model relates to the field of chemical industry, in particular to nitrous gas recovery unit and method.
Background
Chemical enterprises utilize cyclohexanol and nitric acid for oxidation to produce adipic acid, tail gas of the chemical enterprises contains a large amount of nitrous gases, and nitrogen oxides (nitric oxide and nitrogen dioxide) contained in the tail gas containing the nitrous gases need to be separated and recovered before the tail gas containing the nitrous gases is discharged.
At present, when chemical enterprises treat the tail gas containing the nitrous gas, the tail gas is firstly mixed with air to convert all nitrogen oxides into nitrogen dioxide, and then the nitrogen dioxide enters an absorption tower to be in countercurrent contact with spray water, so that nitric acid is obtained at the bottom of the tower.
However, the concentration of the nitric acid obtained by the treatment method is low, the nitric acid needs to be concentrated and then sold to the outside as a product, time and labor are wasted, and in addition, in order to reduce the content of the nitrogen oxides in the discharged tail gas as much as possible, a plurality of sets of absorption towers need to be designed, and the alkali liquor is used as absorption liquid to remove the residual nitrogen oxides in the tail gas, so that the comprehensive treatment cost is high.
Therefore, how to recycle the nitrous gases in the tail gas with high efficiency and low cost is a problem to be solved urgently by the technical personnel in the field.
Disclosure of Invention
The utility model aims at prior art not enough, provide a nitrous gas recovery unit, its simple structure, convenient operation, but low cost, high efficiency recycle nitrous gas, especially the nitrous gas in the tail gas, and satisfy the environmental protection requirement.
Realize the utility model discloses the technical scheme of purpose is: a nitrous gas recovery device comprises a liquid ring compressor, a first absorption tower, a second absorption tower, a first return pipeline, a second return pipeline and a third return pipeline, wherein an air inlet of the liquid ring compressor is used for being connected with a nitrous gas source and an oxygen source, an air outlet of the liquid ring compressor is connected with the bottom of the side wall of the first absorption tower through the first pipeline, a compressed air inlet is formed in the first pipeline, the first absorption tower is a packed tower, a first packing absorption section, a second packing absorption section and a third packing absorption section are arranged on the first absorption tower from top to bottom at intervals, a first distributor is arranged above the first packing absorption section, a first liquid phase collecting tank is arranged below the first packing absorption section, a second distributor is arranged above the second packing absorption section, and a second liquid phase collecting tank is arranged below the second packing absorption section, and a third distributor is arranged above the third packing absorption section, the upstream end of the first reflux pipeline is connected with the first liquid phase collecting tank, the downstream end of the first reflux pipeline is connected with the first distributor, a first reflux pump and a first cooler are arranged on the first reflux pipeline, the upstream end of the second reflux pipeline is connected with the second liquid phase collecting tank, the downstream end of the second reflux pipeline is connected with the second distributor, a second reflux pump and a second cooler are arranged on the second reflux pipeline, the upstream end of the third reflux pipeline is connected with the tower bottom of the first absorption tower, the downstream end of the third reflux pipeline is connected with a third distributor, a third reflux pump and a third cooler are arranged on the third reflux pipeline, the number of the second absorption towers is one or more, the second absorption towers are integrally connected in series, and the gas phase inlet of the second absorption tower is connected with the tower top of the first absorption tower through the second pipeline.
Preferably, the number of the second absorption tower is three.
Furthermore, the absorption tower further comprises a fourth return pipeline, the upstream end of the fourth return pipeline is connected with the bottom of the second absorption tower, the downstream end of the fourth return pipeline is connected with the side wall of the second absorption tower, and a fourth return pump and a fourth cooler are arranged on the fourth return pipeline.
Preferably, the third cooler comprises a precooling heat exchanger and a refrigerating heat exchanger which are connected in series, the precooling heat exchanger is located at the upstream of the refrigerating heat exchanger, the cooling medium of the precooling heat exchanger is circulating water, and the cooling medium of the refrigerating heat exchanger is chilled water.
Adopt above-mentioned technical scheme to have following beneficial effect:
1. nitrous gas recovery unit includes liquid ring compressor, first absorption tower, the second absorption tower, first return line, the second return line, the third return line, wherein, liquid ring compressor is used for pressurizeing nitrous gas, and utilize liquid ring water to absorb nitrous dioxide that nitrous gas oxidation generated, as the absorption lean liquor of first absorption tower, can effectively improve the concentration of the nitric acid that first absorption tower generated, in addition, adopt liquid ring compressor still can play cooling effect to nitrous gas, improve the recycle efficiency to nitrous gas, and reduce the recycle energy consumption of nitrous gas. The air inlet of the liquid ring compressor is used for being connected with a nitrous gas source and an oxygen source, the exhaust port of the liquid ring compressor is connected with the bottom of the side wall of the first absorption tower through the first pipeline, a compressed air inlet is formed in the first pipeline and used for providing compressed air, on the basis that all nitrous gases are converted into nitrogen dioxide, the pressure in the first absorption tower is further improved, the absorption efficiency of the nitrogen dioxide generated by oxidation is further improved, the concentration of the generated nitric acid is improved, in addition, the generated nitric acid can also be directly discharged outside by utilizing the pressure in the first absorption tower, and the recycling power consumption and the cost of the nitrous gases are further reduced. The first absorption tower is a packed tower, the first absorption tower is provided with a first packing absorption section, a second packing absorption section and a third packing absorption section at intervals from top to bottom, a first distributor is arranged above the first packing absorption section, a first liquid phase collecting tank is arranged below the first packing absorption section, a second distributor is arranged above the second packing absorption section, a second liquid phase collecting tank is arranged below the second packing absorption section, a third distributor is arranged above the third packing absorption section, each designed distributor is used for uniformly distributing absorption lean liquid along the sectional area of the first packing tower, each designed liquid phase collecting tank is used for partially collecting absorption rich liquid flowing out from the upper packing absorption section, and the absorption rich liquid is used as reflux liquid for repeatedly absorbing nitrogen dioxide in the first absorption tower. The upstream end of the first return pipeline is connected with the first liquid phase collecting tank, the downstream end of the first return pipeline is connected with the first distributor, the first return pipeline is provided with a first return pump and a first cooler, and self-circulation is formed at the upper part of the first absorption tower. The upstream end of the second return pipeline is connected with the second liquid phase collecting tank, the downstream end of the second return pipeline is connected with the second distributor, the second return pipeline is provided with a second return pump and a second cooler, and self-circulation is formed in the middle of the first absorption tower. The upstream end of the third return pipeline is connected with the tower bottom of the first absorption tower, the downstream end of the third return pipeline is connected with the third distributor, a third return pump and a third cooler are arranged on the third return pipeline, and self-circulation is formed at the lower part of the first absorption tower. Through three-stage backflow absorption, the absorption efficiency of the absorption barren solution on nitrogen dioxide can be effectively improved. The number of the second absorption towers is one or more, the second absorption towers are connected in series to form a whole, a gas phase inlet of each second absorption tower is connected with the top of the first absorption tower through a second pipeline, and the tail gas containing a small amount of nitrogen dioxide and discharged from the first absorption tower is absorbed again through the second absorption tower, so that the content of nitrogen oxide in the discharged tail gas can be effectively reduced, and the environmental protection requirement is met.
2. The third cooler comprises a precooling heat exchanger and a refrigerating heat exchanger which are connected in series, the precooling heat exchanger is positioned on the upstream of the refrigerating heat exchanger, a cooling medium of the precooling heat exchanger is circulating water, the cooling medium of the refrigerating heat exchanger is chilled water, the circulating water is firstly utilized to primarily cool the circulating liquid phase, the chilled water is then utilized to further cool, the consumption of the chilled water can be effectively reduced on the premise of improving the solubility of the nitrogen dioxide, and the energy consumption of the nitrous gas recycling is reduced.
The following description is further described with reference to the accompanying drawings and the detailed description.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
In the drawing, 1 is a first absorption tower, 2 is a second absorption tower, 3 is a liquid ring compressor, 4 is a first return line, 5 is a second return line, 6 is a third return line, 7 is a compressed air inlet, 8 is a first filler absorption section, 9 is a second filler absorption section, 10 is a third filler absorption section, 11 is a first distributor, 12 is a first liquid phase collection tank, 13 is a second distributor, 14 is a second liquid phase collection tank, 15 is a third distributor, 16 is a first return pump, 17 is a first cooler, 18 is a second return pump, 19 is a second cooler, 20 is a third return pump, 21 is a third cooler, 21a is a precooling heat exchanger, 21b is a refrigeration heat exchanger, 22 is a fourth return line, 23 is a fourth return pump, 24 is a fourth cooler, 101 is a first line, and 102 is a second line.
Detailed Description
Example 1
Referring to fig. 1, the nitrous gas recovery device comprises a liquid ring compressor 3, a first absorption tower 1, a second absorption tower 2, a first return pipeline 4, a second return pipeline 5 and a third return pipeline 6. An air inlet of the liquid ring compressor 3 is used for being connected with a nitrous gas source and an oxygen source, wherein the nitrous gas source is chemical tail gas containing nitrous gas (nitric oxide) generally, and the oxygen source is air generally. The exhaust port of the liquid ring compressor 3 is connected with the bottom of the side wall of the first absorption tower 1 through a first pipeline 101, and the first pipeline 101 is provided with a compressed air inlet 7. The first absorption tower 1 is a packed tower, and the first absorption tower 1 is provided with a first packing absorption section 8, a second packing absorption section 9 and a third packing absorption section 10 at intervals from top to bottom. In the embodiment, the third packing absorption section is located above the downstream end of the first pipeline, and obviously, the cross-sectional area of each liquid phase collection tank is smaller than that of the first absorption tower, so that the absorption rich liquid part passing through the corresponding packing absorption section is intercepted. In order to reduce energy consumption, the third cooler includes a precooling heat exchanger 21a and a refrigerating heat exchanger 21b, and is formed by connecting in series, the precooling heat exchanger is located at the upstream of the refrigerating heat exchanger, the cooling medium of the precooling heat exchanger is circulating water, and the cooling medium of the refrigerating heat exchanger is chilled water. The number of the second absorption towers 2 is three, the second absorption towers are connected in series to form a whole, a gas phase inlet of the second absorption tower located at the upstream is connected with the top of the first absorption tower 1 through a second pipeline 102, a gas outlet of the second absorption tower located at the downstream is used for discharging the treated tail gas, obviously, the second absorption tower further comprises a fourth return pipeline 22, the upstream end of the fourth return pipeline 22 is connected with the bottom of the second absorption tower 2, the downstream end of the fourth return pipeline 22 is connected with the side wall of the second absorption tower 2, and a fourth return pump 23 and a fourth cooler 24 are arranged on the fourth return pipeline 22.
Example 2
The method for recycling the nitrous gas by adopting the nitrous gas recycling device in the embodiment 1 comprises the following steps of:
1) Mixing a nitrous gas source and an oxygen source, compressing the mixture by a liquid ring compressor, oxidizing part of the nitrous gas into nitrogen dioxide, and reacting the nitrogen dioxide with liquid ring water to generate nitric acid, wherein NO in the nitrous gas source 2 The flow rate of (A) is 0.244kg/h, the flow rate of NO is 15.786kg/h, N 2 The flow rate of O is 14843.694kg/h, and the oxygen source is air;
2) Nitric acid generated in the liquid ring compressor is discharged out of the liquid ring compressor and is used as absorption lean liquid of a first absorption tower, the rest nitrous gas is mixed with compressed air and then enters the first absorption tower, the air inlet pressure is 0.175-0.195MPa, the air inlet temperature is 70-80 ℃, the liquid phase temperature of the upstream end of a third backflow pipeline is controlled to be 45-55 ℃, the liquid phase temperature of the downstream end of the third backflow pipeline is controlled to be 25-35 ℃, the liquid phase temperature of the upstream end of the second backflow pipeline is controlled to be 25-35 ℃, the liquid phase temperature of the downstream end of the third backflow pipeline is controlled to be 15-25 ℃, and the liquid phase temperature of the downstream end of the third backflow pipeline is controlled to be 10-20 ℃;
3) The temperature of the gas phase discharged from the top of the first absorption tower is 10-20 ℃, the gas phase enters a second absorption tower, and concentrated nitric acid with the concentration of 51% is discharged from the bottom of the first absorption tower;
4) Controlling the temperature of the gas phase discharged from the top of the second absorption tower at the downstream to be 15-20 ℃, sending the gas phase to a laughing gas emission reduction device, detecting the gas phase to ensure that the content of nitrogen oxides in the gas phase is 381ppm, and calculating to obtain NO in a nitrous gas source 2 Has an absorption rate of 99.994% and an absorption rate of NO of 99.41%.
Claims (4)
1. A nitrous gas recovery unit which characterized in that: comprises a liquid ring compressor (3), a first absorption tower (1), a second absorption tower (2), a first return pipeline (4), a second return pipeline (5) and a third return pipeline (6),
the gas inlet of the liquid ring compressor (3) is used for being connected with a nitrous gas source and an oxygen source, the gas outlet of the liquid ring compressor (3) is connected with the bottom of the side wall of the first absorption tower (1) through a first pipeline (101), a compressed air inlet (7) is arranged on the first pipeline (101),
the first absorption tower (1) is a packed tower, the first absorption tower (1) is provided with a first packing absorption section (8), a second packing absorption section (9) and a third packing absorption section (10) at intervals from top to bottom, a first distributor (11) is arranged above the first packing absorption section (8), a first liquid phase collecting tank (12) is arranged below the first packing absorption section, a second distributor (13) is arranged above the second packing absorption section (9), a second liquid phase collecting tank (14) is arranged below the second packing absorption section, a third distributor (15) is arranged above the third packing absorption section (10),
the upstream end of the first return pipeline (4) is connected with a first liquid phase collecting tank (12), the downstream end of the first return pipeline is connected with a first distributor (11), a first return pump (16) and a first cooler (17) are arranged on the first return pipeline (4),
the upstream end of the second return pipeline (5) is connected with a second liquid phase collecting tank (14), the downstream end of the second return pipeline is connected with a second distributor (13), a second return pump (18) and a second cooler (19) are arranged on the second return pipeline (5),
the upstream end of the third return pipeline (6) is connected with the bottom of the first absorption tower (1), the downstream end is connected with a third distributor (15), a third return pump (20) and a third cooler (21) are arranged on the third return pipeline (6),
the number of the second absorption towers (2) is one or more, the second absorption towers are connected in series to form a whole, and the gas phase inlets of the second absorption towers (2) are connected with the top of the first absorption tower (1) through second pipelines (102).
2. A nitrous gas recovery device according to claim 1, characterized in that: the number of the second absorption towers (2) is three.
3. A nitrous gas recovery device according to claim 1 or 2, characterized in that: the absorption tower is characterized by further comprising a fourth return pipeline (22), the upstream end of the fourth return pipeline (22) is connected with the bottom of the second absorption tower (2), the downstream end of the fourth return pipeline (22) is connected with the side wall of the second absorption tower (2), and a fourth return pump (23) and a fourth cooler (24) are arranged on the fourth return pipeline (22).
4. A nitrous gas recovery device according to claim 1, characterized in that: the third cooler (21) comprises a precooling heat exchanger (21 a) and a refrigerating heat exchanger (21 b) which are connected in series, the precooling heat exchanger is positioned at the upstream of the refrigerating heat exchanger, a cooling medium of the precooling heat exchanger is circulating water, and the cooling medium of the refrigerating heat exchanger is chilled water.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222266731.3U CN218249418U (en) | 2022-08-26 | 2022-08-26 | Nitrous gas recovery unit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202222266731.3U CN218249418U (en) | 2022-08-26 | 2022-08-26 | Nitrous gas recovery unit |
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| CN218249418U true CN218249418U (en) | 2023-01-10 |
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| CN202222266731.3U Active CN218249418U (en) | 2022-08-26 | 2022-08-26 | Nitrous gas recovery unit |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115430262A (en) * | 2022-08-26 | 2022-12-06 | 重庆华峰化工有限公司 | Nitrous gas recovery device and method |
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- 2022-08-26 CN CN202222266731.3U patent/CN218249418U/en active Active
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115430262A (en) * | 2022-08-26 | 2022-12-06 | 重庆华峰化工有限公司 | Nitrous gas recovery device and method |
| CN115430262B (en) * | 2022-08-26 | 2023-09-01 | 重庆华峰化工有限公司 | Device and method for recycling nitrous gases |
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