Distillation device

Abstract

The utility model discloses a distillation device and belongs to the technical field of organic synthesis. Comprising a coarse distillation tower, a condenser, a fractional condenser, a fine distillation tower, a pump, a reboiler and a heat exchanger, a discharge port of the coarse distillation tower is connected with a reflux inlet of the fine distillation tower through a liquid phase pipeline with the pump, the reboiler is connected with the bottom of the fine distillation tower, and an exhaust port of the fine distillation tower is connected with a gas inlet of the coarse distillation tower through a gas phase pipeline; a cold water inlet of the heat exchanger is connected with the waste liquid storage tank through a pipeline, a hot water outlet is connected with a feed port of the coarse distillation tower through a pipeline, and a hot water inlet is connected with a discharge port of the fine distillation tower through a pipeline; tower plates of the coarse distillation tower are inclined hole tower plates, tower plates of the fine distillation tower are float valve tower plates, and the number of layers of the tower plates of the fine distillation tower is larger than or equal to that of the tower plates of the coarse distillation tower. An existing distillation tower is improved, and the fine distillation tower, the pump, the reboiler and the heat exchanger are added, so that the ammonia content of wastewater output by the fine distillation tower can be reduced, and the wastewater treatment capacity is improved.

Description

Technical Field

[0001] This utility model belongs to the field of organic synthesis technology, and specifically relates to a distillation apparatus. Background Technology

[0002] Ammonia is an inorganic compound with the chemical formula NH3 and a molecular weight of 17.031. Under standard conditions, its density is 0.771 g / L, and its relative density is 0.5971 (air = 1.00). It is a colorless gas with a strong, pungent odor. It can be liquefied under pressure at room temperature, has a boiling point of -33.5℃, and is soluble in water, ethanol, and ether.

[0003] In chemical and scientific research fields, it is used as a standard gas, for preparing standard mixed gases, for property determination, and for nitriding silicon or silicon oxide. In the inorganic chemical industry, it is used in the synthesis of ammonium salts, nitric acid, hydrogen cyanide, hydrazine, hydroxylamine, thiamine, nitramine, phosphamide, urea, etc. In the organic chemical industry, liquid ammonia can be reacted with alkyl chlorides or alcohols to prepare alkylamines, such as the reaction of 1,2-dichloroethane to produce ethylenediamine. It can also be used as a refrigerant and alkali.

[0004] In ammonia-involved organic synthesis, after the reaction is complete, the wastewater contains ammonia, organic solvents, by-products, and unreacted raw materials. Ammonia is a volatile gas and can be recovered from the mother liquor. Currently, distillation towers are used to recover ammonia from the wastewater.

[0005] For example, patent application number CN201710416334.0 discloses a device for recovering low-boiling-point substances, which includes: a distillation column, which contacts a raw liquid containing low-boiling-point substances with heated water vapor, causing the low-boiling-point substances to be separated from the raw liquid and vaporized and discharged from the top of the column as vapor containing low-boiling-point substances, and storing the treated water after removing the low-boiling-point substances from the raw liquid at the bottom of the column.

[0006] For example, patent application number CN201721345280.5 discloses an ammonia recovery device, including an ammonia recovery tank connected to an ammonia gas pipe and a distilled water tank connected to a distillation tail gas pipe. The ammonia recovery tank is filled with pure water for recovering ammonia gas; the distilled water tank is used to recover distilled water containing ammonia; the ammonia recovery tank is connected to the pure water pipe, and the outlet of the ammonia gas pipe is located below the pure water liquid level in the ammonia recovery tank; a water seal pipe is provided at the top of the ammonia recovery tank; the ammonia gas pipe and the distillation tail gas pipe are both connected to the exhaust pipe of the distillation tower.

[0007] For example, patent application number CN202411985707.2 discloses an ammonia stripping, dehydration, and purification system for alkanolamine products, including: an ammonia stripping device that receives pretreated alkanolamine raw materials and separates ammonia and water in the raw materials in gaseous form by heating. The ammonia stripping device includes an ammonia stripping tower, an ammonia stripping tower reboiler, an ammonia stripping tower condenser, and an ammonia flash tank. The ammonia stripping tower is divided into an ammonia flash section and an ammonia distillation section. The ammonia flash section is used for preliminary separation of ammonia gas, and the ammonia distillation section is used for further separation of ammonia and water. The ammonia stripping tower reboiler provides heat to maintain the vaporization of the material in the ammonia distillation section. The ammonia stripping tower condenser is used to condense the separated ammonia gas, and the ammonia flash tank is used to further remove residual ammonia from the material under reduced pressure.

[0008] For example, patent application number CN201020149296.0 discloses a distillation device for ammonia recovery. The device is provided with a distillation column, a preheater and a cooler from bottom to top. The bottom and upper side walls of the distillation column are respectively provided with an ammonia removal liquid outlet and a liquid inlet. The side wall of the preheater is provided with an ammonia-containing liquid inlet and an ammonia-containing liquid outlet. The top of the cooler is provided with an ammonia gas outlet. The ammonia-containing liquid outlet and the liquid inlet are connected by a pipe.

[0009] Existing ammonia distillation recovery units such as Figure 1 As shown, the system includes a crude distillation column 1, a condenser 2, a partial condenser 3, and a primary reboiler 10. The crude distillation column 1 is a floating valve tray column with 19 trays. A wastewater storage tank is connected to the feed inlet at the top of the crude distillation column 1 via a pipeline. The inlet of the condenser 2 is connected to the exhaust port at the top of the crude distillation column 1, and its condensate outlet is connected to a light phase storage tank (containing a mixture of ammonia, water, and solvents) and a reflux port at the top of the crude distillation column 1. The partial condenser 3 is connected to the middle of the crude distillation column 1, and its condensate outlet (part of the condensate is returned to the crude distillation column 1, outputting ammonia water) is connected to an ammonia water storage tank via a pipeline. The primary reboiler 10 is connected to the bottom of the crude distillation column 1, heating the liquid at the bottom of the column and converting it into gas, which is then sent to the inlet at the bottom of the column.

[0010] The applicant discovered the following problems when using the aforementioned ammonia distillation recovery device:

[0011] 1. The wastewater contains a small amount of particulate matter, which can easily clog the crude distillation tower and the original reboiler;

[0012] 2. The free ammonia content in the wastewater output from the crude distillation tower is greater than 250 mg / L, which not only wastes ammonia but also increases the difficulty of wastewater treatment. Utility Model Content

[0013] To address the aforementioned problems, this utility model provides a distillation apparatus. This patent improves upon existing distillation columns by adding a rectifying distillation column, a pump, a reboiler, and a heat exchanger, thereby reducing the ammonia content in the wastewater output from the rectifying distillation column, increasing the wastewater treatment capacity, and reducing the possibility of distillation column blockage. The technical solution is as follows:

[0014] This utility model provides a distillation apparatus, including a crude distillation column 1, a condenser 2, a fractionating condenser 3, a rectifying distillation column 4, a pump 5, a reboiler 6, and a heat exchanger 7. The discharge port at the bottom of the crude distillation column 1 is connected to the reflux port at the top of the rectifying distillation column 4 via a liquid phase pipeline 8 connected to the pump 5. The reboiler 6 is connected to the bottom of the rectifying distillation column 4. The exhaust port at the top of the rectifying distillation column 4 is connected to the gas inlet at the bottom of the crude distillation column 1 via a gas phase pipeline 9. The cold water inlet of the heat exchanger 7 is connected to a waste liquid storage tank via a pipeline, and its hot water outlet is connected to the feed port at the top of the crude distillation column 1 via a pipeline. Its hot water inlet is connected to the discharge port at the bottom of the rectifying distillation column 4 via a pipeline. The trays of the crude distillation column 1 are inclined hole trays, and the trays of the rectifying distillation column 4 are floating valve trays. The number of trays in the rectifying distillation column 4 is greater than or equal to the number of trays in the crude distillation column 1.

[0015] In this embodiment of the invention, the air inlet of the condenser 2 is connected to the exhaust port at the top of the crude distillation column 1, and its condensate outlet is connected to the light phase storage tank and the reflux port at the top of the crude distillation column 1; the fractional condenser 3 is connected to the middle part of the crude distillation column 1, and the condensate outlet of the fractional condenser 3 is connected to the ammonia storage tank through a pipeline.

[0016] In this embodiment of the invention, the heat exchanger 7 is lower than the distillation column 4 and is a tube-and-shell heat exchanger.

[0017] In this embodiment of the present invention, the diameter of the distillation column 4 is 1.8-2.4m.

[0018] Specifically, in this embodiment of the present invention, the distillation column 4 has 20 trays, and the crude distillation column 1 has 19 trays.

[0019] Specifically, in this embodiment of the invention, there are three reboilers 6, which are heated by steam at 0.8 MPa and are used in a two-on-one standby configuration.

[0020] Specifically, in this embodiment of the present invention, there are two pumps 5 with a head of 40m, which are used in a one-on-one standby manner.

[0021] The beneficial effects of the technical solution provided by this utility model embodiment are as follows: This utility model embodiment provides a distillation apparatus in which the ammonia concentration collected by the condenser is greater than 10 wt%, and the ammonia content of the distillation residue in the rectifying column is less than 80 mg / L. The processing capacity of this apparatus is approximately 1.3 times that of existing apparatuses, and it has greater operational flexibility. The service life of the crude distillation column and the rectifying column is longer than that of the prior art. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of an existing distillation apparatus;

[0023] Figure 2 This is a schematic block diagram of the distillation apparatus in an embodiment of this utility model;

[0024] Figure 3 This is a schematic diagram of the distillation apparatus in an embodiment of this utility model.

[0025] In the diagram: 1. Crude distillation column, 2. Condenser, 3. Separate condenser, 4. Fine distillation column, 5. Pump, 6. Reboiler, 7. Heat exchanger, 8. Liquid phase pipeline, 9. Gas phase pipeline, 10. Raw reboiler. Detailed Implementation

[0026] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0027] Example 1

[0028] See Figure 2-3Example 1 provides a distillation apparatus, including a crude distillation column 1, a condenser 2, a partial condenser 3, a rectifying distillation column 4, a pump 5, a reboiler 6, and a heat exchanger 7, etc., with the reboiler of the crude distillation column 1 removed. The inlet of the condenser 2 is connected to the exhaust port at the top of the crude distillation column 1, and its condensate outlet is connected to a light phase storage tank (outputting the light phase) and a reflux port at the top of the crude distillation column 1. The partial condenser 3 is connected to the middle of the crude distillation column 1, and its condensate outlet (partial condensate reflux) is connected to a heavy phase storage tank via a pipeline. The outlet at the bottom of the crude distillation column 1 is connected to the reflux port at the top of the rectifying column 4 via a liquid phase pipeline 8 equipped with pump 5 (outputting the distillation residue of the crude distillation column 1). The reboiler 6 is connected to the bottom of the rectifying column 4, and its configuration is consistent with the prior art, heating the liquid phase to obtain a gas phase, which is then fed into the rectifying column 4. The exhaust port at the top of the rectifying column 4 is connected to the inlet at the bottom of the crude distillation column 1 (in the prior art, this is connected to the original reboiler 10) via a gas phase pipeline 9 (which sends the gas phase into the crude distillation column 1). In the crude distillation column 1, the gas phase from the rectifying column 4 comes into countercurrent contact with the wastewater to achieve distillation. Since the gas phase from the rectifying column 4 is used, the gas phase from the crude distillation column 1 is insufficient. Therefore, this patent heats the wastewater (by exchanging heat with the distillation residue from the rectifying column 4) to ensure the distillation effect. Specifically, the cold water inlet of the heat exchanger 7 is connected to the wastewater storage tank via a pipeline, its hot water outlet is connected to the feed inlet at the top of the crude distillation column 1 via a pipeline, its hot water inlet is connected to the discharge outlet at the bottom of the rectifying column 4 via a pipeline, and its cold water outlet is connected to a wastewater treatment device via a pipeline. The trays of the crude distillation column 1 are perforated trays, and the trays of the rectifying column 4 are valve trays. The number of trays in the rectifying column 4 is greater than or equal to the number of trays in the roughing column 1, and the tray spacing in the rectifying column 4 is the same as that in the roughing column 1. Inclined-hole trays are less prone to clogging than valve trays. Particulate impurities dissolve, shrink, settle, or are discharged with the heavy phase in the roughing column 1, and also settle in the pipes. Therefore, the particles entering the rectifying column 4 are smaller, softer, and fewer in number. Consequently, the rectifying column 4 (which uses valve trays to increase the number of trays to ensure distillation efficiency) and the reboiler 6 are less prone to clogging.

[0029] In this embodiment of the invention, the heat exchanger 7 is lower than the distillation column 4 and is a tube heat exchanger, etc.

[0030] In this embodiment of the present invention, the diameter of the distillation column 4 is 1.8-2.4m, and the diameter and height of the crude distillation column 1 are consistent with the prior art.

[0031] In this embodiment, the reboiler 6 requires higher power than the original reboiler 10 to ensure the steam volume of the crude distillation column 1 (energy is lost during pipeline transportation); the power of the reboiler 6 is at least 1.3 times that of the original reboiler 10.

[0032] Example 2

[0033] Example 2 provides a distillation apparatus, the structure of which is basically the same as that of Example 1, except that: the distillation apparatus in this example is used for ammonia recovery, and the heavy phase storage tank is an ammonia storage tank, and the concentration of ammonia in the ammonia storage tank is greater than or equal to 10 wt%.

[0034] Example 3

[0035] Example 3 provides a distillation apparatus, the structure of which is basically the same as that of Example 1, except that: in this example, there are 3 reboilers 6 and they are heated by 0.8 MPa steam, and they are used in a two-on-one standby mode.

[0036] Example 4

[0037] Example 4 provides a distillation apparatus, the structure of which is basically the same as that of Example 1, except that: in this example, there are 2 pumps 5 with a head of 40m, and they are used in a one-on-one standby manner.

[0038] Example 5

[0039] Example 5 provides a distillation apparatus whose structure is basically the same as that of Example 2, except that: the diameter of the rectifying column 4 in this example is 2m, the number of trays in the rectifying column 4 is 20, and the number of trays in the crude distillation column 1 is 19. The ammonia concentration collected from the condenser 3 is greater than 10wt%, and the ammonia content of the distillation residue in the rectifying column 4 is less than 80mg / L. The throughput of this apparatus is approximately 1.3 times that of existing apparatuses (the throughput of existing apparatuses is 70t / h, while that of this patent is 90t / h), with an operational flexibility of 50-120%. The service life of the crude distillation column 1 and the rectifying column 4 is longer than that of existing technologies.

[0040] In this patent, pumps, valves, or flow meters may be installed on the pipelines between the various structures as needed.

[0041] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. Distillation apparatus comprising a crude distillation column (1), a condenser (2) and a splitter (3); characterized in that, The distillation device further comprises a rectifying tower (4), a pump (5), a reboiler (6) and a heat exchanger (7), the outlet of the bottom of the crude distillation tower (1) is connected with the reflux inlet of the upper part of the rectifying tower (4) through a liquid phase pipeline (8) with the pump (5), the reboiler (6) is connected with the bottom of the rectifying tower (4), the gas outlet of the top of the rectifying tower (4) is connected with the gas inlet of the lower part of the crude distillation tower (1) through a gas phase pipeline (9); the cold water inlet of the heat exchanger (7) is connected with the waste liquid storage tank through a pipeline, the hot water outlet thereof is connected with the feed inlet of the upper part of the crude distillation tower (1) through a pipeline, and the hot water inlet thereof is connected with the outlet of the bottom of the rectifying tower (4) through a pipeline; the tray of the crude distillation tower (1) is a slant hole tray, the tray of the rectifying tower (4) is a float valve tray, and the number of the tray layers of the rectifying tower (4) is greater than or equal to that of the crude distillation tower (1).

2. The distillation apparatus of claim 1, wherein, The gas inlet of the condenser (2) is connected with the gas outlet of the top of the crude distillation tower (1), and the condensed liquid outlet thereof is connected with the light phase storage tank and the reflux inlet of the upper part of the crude distillation tower (1); the partial condenser (3) is connected with the middle part of the crude distillation tower (1), and the condensed liquid outlet of the partial condenser (3) is connected with the ammonia water storage tank through a pipeline.

3. The distillation apparatus of claim 1, wherein, The heat exchanger (7) is lower than the rectifying tower (4), and it is a column heat exchanger.

4. The distillation apparatus of claim 1, wherein, The column diameter of the rectifying tower (4) is 1.8-2.4 m.

5. The distillation apparatus of claim 1, wherein, The number of the tray layers of the rectifying tower (4) is 20, and the number of the tray layers of the crude distillation tower (1) is 19.

6. The distillation apparatus of claim 1, wherein, The number of the reboiler (6) is 3, and it is heated by 0.8 Mpa steam and used in a two-open-one-backup mode.

7. The distillation apparatus of claim 1, wherein, The number of the pump (5) is 2, and the lift thereof is 40 m, and it is used in a one-open-one-backup mode.

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