Glycine centrifugal mother liquor recovery device

Abstract

The utility model provides a glycine centrifugal mother liquor recovery device, which comprises a pressurizing tower and an atmospheric tower, the lower parts of the pressurizing tower and the atmospheric tower are respectively connected with a pressurizing tower reboiler and an atmospheric tower reboiler, the top of the pressurizing tower is connected with the atmospheric tower reboiler, the output pipeline of the atmospheric tower reboiler is connected with a pressurizing tower return tank, and the output pipeline of the atmospheric tower reboiler is connected with the pressurizing tower return tank. The pressurizing tower reflux tank is connected with the feeding preheater through a heat exchange pipeline, the heat exchange pipeline is connected with the pressurizing tower reflux pipeline, and the feeding preheater is connected with the pressurizing tower methanol extraction device; the pressurizing tower return tank is connected with the atmospheric tower methanol extraction device; according to the invention, methanol is recovered by connecting the two towers in series, and high-temperature methanol steam at the top of the pressurized tower provides a heat source for a reboiler of the atmospheric tower, so that a thermal coupling process of double-tower operation is realized, and the heat consumption is greatly reduced; high-temperature methanol liquid extracted from the top of the pressurizing tower is used for preheating raw materials, so that the product energy consumption is reduced; and only one set of cooling system needs to be arranged at the tower top of the atmospheric tower, so that the structure of the equipment is simplified, and the manufacturing cost is reduced.

Description

Technical Field

[0001] The present application relates to the technical field of glycine processing, and in particular to a device for recovering glycine centrifugal mother liquor. Background Art

[0002] Glycine, also known as aminoacetic acid, is an important chemical intermediate. Its consumption in various fields is ranked from high to low, in the order of pesticides, food, feed, and medicine. In my country, about 80% of glycine is used to produce the herbicide glyphosate. At present, the domestic production of glycine still adopts the mainstream chloroacetic acid ammonolysis method: first synthesize a mixed solution of glycine and ammonium chloride in water, then use a large amount of methanol to extract and separate glycine, produce a large amount of methanol mother liquor, and then use a single-effect atmospheric pressure methanol distillation tower to recover the methanol in the mother liquor. In the process of extracting glycine, it is preliminarily estimated that 8-10m3 of methanol needs to be added to produce 1 ton of glycine. 3 Methanol, producing 12-12.5m 3 The methanol mother liquor has a complex composition. The components of the methanol mother liquor are: 68.5-70% methanol, 7% ammonium chloride, 1.3% hexamethylenetetramine, 1.5% glycine, 20-23% water, and 2.2% other organic matter. Based on the scale of 100,000 tons of glycine per year, 3600-4000m3 of methanol needs to be processed per day. 3 The methanol mother liquor is processed by a single-effect atmospheric distillation tower. At present, most glycine companies use a single-effect atmospheric distillation tower to process the methanol mother liquor. The steam consumption is large, and the methanol secondary steam is not fully utilized. It is preliminarily estimated that 0.4-0.42 tons of low-pressure steam is required to process each cubic meter of methanol. In the glycine production, the methanol recovery process requires 5-5.2 tons of low-pressure steam, which consumes a lot of energy.

[0003] In recent years, glycine companies have been competing to develop new process technologies for non-extraction production of glycine to significantly reduce energy consumption. For companies that already have a considerable scale of extraction production of glycine, it is difficult to completely abandon the single-effect atmospheric distillation process and equipment. Therefore, it is of great significance to carry out technological innovation and upgrading of existing production technologies to achieve the goal of energy conservation and emission reduction.

[0004] In order to improve the processing capacity, some existing technologies have begun to use multi-effect distillation towers to treat methanol mother liquor, such as a method and device for recovering methanol in industrial-grade glycine production with application number CN202210422029.3, which discloses a methanol recovery device in industrial-grade glycine production, including a preheater, which is connected to a vacuum distillation tower; the top of the vacuum distillation tower is connected to a vacuum tower top condenser, which is connected to a vacuum tower top reflux tank, and the vacuum tower top reflux tank is connected to the vacuum tower top, the product reflux tank and the vacuum tower top reflux pump. tank; the bottom of the vacuum distillation tower is connected to the pressurized distillation tower via the vacuum distillation tower extraction pump; the pressurized distillation tower is connected to the vacuum distillation tower via the vacuum distillation tower reboiler; the vacuum distillation tower reboiler is connected to the pressurized tower reflux tank via the pressurized tower post condenser; the pressurized tower reflux tank is respectively connected to the pressurized distillation tower and the finished product tank via the pressurized tower reflux pump; this application mainly utilizes the double-effect distillation technology to effectively reduce the steam consumption in the methanol recovery process, through the coupling design of the pressure and processing capacity of the two distillation towers, the steam at the top of the pressurized tower is used to provide heat for the low-pressure tower, and finally the methanol recovery is realized.

[0005] Although the application designs two distillation towers to increase the processing capacity, the application does not fully utilize the heat at the top of the tower and does not exchange heat with the preheater. In addition, a condenser is set on each tower in the application, which increases the complexity of the equipment and increases the manufacturing cost of the equipment. Moreover, the application uses a vacuum unit, which is prone to leakage, thereby affecting the recovery of methanol in glycine production.

[0006] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Utility Model Content

[0007] The present application provides a glycine centrifugal mother liquor recovery device, comprising a pressurized tower, a feed pipeline is provided on one side of the pressurized tower, a feed preheater is provided on the feed pipeline, the pressurized tower is connected to an atmospheric pressure tower, the lower parts of the pressurized tower and the atmospheric pressure tower are respectively connected to a pressurized tower reboiler and an atmospheric pressure tower reboiler, the top of the pressurized tower is connected to the atmospheric pressure tower reboiler through a production pipeline at the top of the pressurized tower, the output pipeline of the atmospheric pressure tower reboiler is connected to a pressurized tower reflux tank, the bottom of the pressurized tower reflux tank is connected to the feed preheater through a heat exchange pipeline, the heat exchange pipeline is also connected to a pressurized tower reflux pipeline, the pressurized tower reflux pipeline is connected to the middle and upper part of the pressurized tower, the feed preheater is connected to a pressurized tower methanol production device; the top of the pressurized tower reflux tank is connected to the atmospheric pressure tower methanol production device at the top of the atmospheric pressure tower through a gas phase pipeline.

[0008] As a preferred solution, a pressure tower reboiler circulation pump is provided at the lower part of the pressure tower reboiler.

[0009] As a preferred solution, an atmospheric tower reboiler circulation pump is provided at the lower part of the atmospheric tower reboiler.

[0010] As a preferred embodiment, the atmospheric tower methanol production device includes an atmospheric tower reflux tank, which is connected to the top of the atmospheric tower through an atmospheric tower top production pipeline, a first-stage atmospheric tower condenser is arranged on the atmospheric tower top production pipeline, an atmospheric tower methanol production pipeline is arranged at the bottom of the atmospheric tower reflux tank, an atmospheric tower product cooler is arranged on the atmospheric tower methanol production pipeline, the atmospheric tower methanol production pipeline is connected to the atmospheric tower reflux pipeline, and the atmospheric tower reflux pipeline is connected to the middle and upper part of the atmospheric tower.

[0011] As a preferred solution, the input end of the atmospheric tower product cooler is connected to the liquid inlet pipeline, and the output end of the atmospheric tower product cooler is connected to the liquid outlet pipeline.

[0012] As a preferred solution, a liquid outlet pipeline control valve is provided on the liquid outlet pipeline.

[0013] As a preferred solution, a liquid level control valve is provided on the methanol production pipeline of the atmospheric pressure tower.

[0014] As a preferred solution, the input end of the primary atmospheric pressure tower condenser is connected to the water inlet pipeline, and the output end of the primary atmospheric pressure tower condenser is connected to the water outlet pipeline.

[0015] As a preferred solution, a water outlet control valve is provided on the water outlet pipeline.

[0016] As a preferred solution, the atmospheric tower top production pipeline is connected to atmospheric tower top production pipeline 2, and a secondary atmospheric tower condenser is provided on the atmospheric tower top production pipeline 2.

[0017] As a preferred embodiment, the pressurized tower methanol production device comprises a pressurized tower methanol production pipeline connected to a feed preheater, and a cooler is provided on the pressurized tower methanol production pipeline.

[0018] As a preferred solution, one end of the methanol extraction pipeline of the pressure tower is connected to the pressure tower product tank.

[0019] As a preferred solution, a pressurizing tower reflux tank liquid level control valve is provided on the pressurizing tower methanol extraction pipeline at the lower part of the cooler.

[0020] As a preferred solution, the inlet of the cooler is connected to the circulating water inlet pipe, and the outlet of the cooler is connected to the circulating water outlet pipe.

[0021] As a preferred solution, a water outlet pipe valve is provided on the water outlet pipe.

[0022] As a preferred solution, a feed control valve is provided on the feed pipeline.

[0023] As a preferred solution, the input end of the pressurized tower reboiler is connected to the steam pipeline, and the output end of the pressurized tower reboiler is connected to the steam condensate pipeline.

[0024] As a preferred solution, a steam pipe valve is provided on the steam pipe.

[0025] As a preferred solution, a pressurized tower reflux control valve is provided on the pressurized tower reflux pipeline.

[0026] As a preferred solution, a gas phase regulating valve is provided on the gas phase pipeline.

[0027] As a preferred solution, an atmospheric tower reflux control valve is provided on the atmospheric tower reflux pipeline.

[0028] As a preferred solution, a steam condensate feed pipeline is provided on one side of the atmospheric pressure tower.

[0029] As a preferred solution, a steam condensate control valve is provided on the steam condensate feed pipeline.

[0030] The present application changes the traditional glycine centrifugal mother liquor stripping process and adopts a double tower series connection to recover methanol. The first pressure tower adopts a pressurized operation, and the second atmospheric pressure tower adopts an atmospheric pressure operation. The high-temperature methanol vapor at the top of the pressure tower provides a heat source for the atmospheric pressure tower reboiler, thereby realizing a thermal coupling process of the double tower operation and greatly reducing the heat consumption. At the same time, the high-temperature methanol liquid extracted from the top of the pressure tower is used to preheat the raw material, further reducing the energy consumption of the product. Moreover, the present application only needs to set up a cooling system at the top of the atmospheric pressure tower, thereby simplifying the structure of the equipment and reducing the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a schematic diagram of the structure of this application;

[0032] 1. Pressure tower; 2. Feed pipeline; 3. Pressure tower feed pump; 4. Feed preheater; 5. Feed control valve; 6. Atmospheric tower; 7. Pressure tower kettle extraction pipeline; 8. Pressure tower flow control valve; 9. Pressure tower reboiler; 10. Atmospheric tower reboiler; 11. Pressure tower reboiler circulation pump; 12. Atmospheric tower reboiler circulation pump; 13. Atmospheric tower kettle extraction pipeline; 14. Atmospheric tower kettle discharge pump; 15, atmospheric tower flow control valve; 16, steam pipeline; 17, steam condensate pipeline; 18, steam pipeline valve; 19, top extraction pipeline of pressure tower; 20, output pipeline; 21, pressure tower reflux tank; 22, heat exchange pipeline; 23, pressure tower reflux pump; 24, pressure tower reflux pipeline; 25, pressure tower reflux control valve; 26, gas phase pipeline; 27, gas phase regulating valve; 28, Steam condensate feed pipeline; 29, steam condensate control valve; 30, atmospheric tower reflux tank; 31, atmospheric tower top production pipeline; 32, atmospheric tower methanol production pipeline; 33, atmospheric tower reflux pump; 34, atmospheric tower product cooler; 35, liquid inlet pipeline; 36, liquid outlet pipeline; 37, liquid outlet pipeline control valve; 38, atmospheric tower reflux pipeline; 39, atmospheric tower reflux control valve; 40, liquid level control valve; 41, primary atmospheric tower condenser; 42, atmospheric tower top production pipeline II; 43, secondary atmospheric tower condenser; 44, water inlet pipeline; 45, water outlet pipeline; 46, water outlet control valve; 47, pressurized tower methanol production pipeline; 48, cooler; 49, circulating water inlet pipeline; 50, circulating water outlet pipeline; 51, water outlet pipeline valve; 52, pressurized tower reflux tank liquid level control valve. DETAILED DESCRIPTION

[0033] The following is combined with Figure 1 The specific implementation of the utility model is described in detail. It should be noted that the specific implementation described here is only used to illustrate and explain the utility model, and is not used to limit the utility model.

[0034] Embodiment 1:

[0035] The present embodiment provides a glycine centrifugal mother liquor recovery device, comprising a pressure tower 1, the pressure tower 1 adopts a pressurized operation, the operating pressure is 5-10 kg (gauge pressure), one side of the pressure tower 1 is connected to a feed pipeline 2, the feed pipeline 2 is provided with a pressure tower feed pump 3 and a feed preheater 4, the raw material is pressurized by the pressure tower feed pump 3 and preheated by the feed preheater 4, so that the material enters the pressure tower 1 through the feed pipeline 2; preferably, a feed control valve 5 is provided on the feed pipeline 2, and the feed control valve 5 is used to control the feed flow rate of the material; the pressure tower 1 is connected to the atmospheric pressure tower 6, specifically, the pressure tower kettle extraction pipeline 7 at the bottom of the pressure tower 1 is connected to the middle and upper part of the atmospheric pressure tower 6, preferably The pressure tower kettle extraction pipeline 7 is provided with a pressure tower flow control valve 8, and the flow rate of the material in the pressure tower kettle extraction pipeline 7 is controlled by the pressure tower flow control valve 8. Specifically, by monitoring the liquid level of the pressure tower kettle of the pressure tower 1, the opening of the pressure tower flow control valve 8 is adjusted in real time according to the liquid level of the pressure tower kettle, so as to control the flow rate of the material in the pressure tower kettle extraction pipeline 7. The lower parts of the pressure tower 1 and the atmospheric tower 6 are respectively connected with a pressure tower reboiler 9 and an atmospheric tower reboiler 10. The atmospheric tower reboiler 10 adopts a coupled reboiler. Preferably, the lower part of the pressure tower reboiler 9 is provided with a pressure tower reboiler circulation pump 11, and the pressure tower reboiler circulation pump 11 increases the circulation of the pressure tower reboiler 9. Driving force, fully preventing the risk of insufficient siphon capacity of the pressure tower reboiler 9 due to excessive salt content; an atmospheric tower reboiler circulating pump 12 is provided at the lower part of the atmospheric tower reboiler 10, and the atmospheric tower reboiler circulating pump 12 is used to increase the driving force for the circulating liquid to prevent insufficient mass transfer driving force due to excessive salt content; an atmospheric tower kettle extraction pipeline 13 is provided at the bottom of the atmospheric tower 6, which is used to extract the high-concentration salt liquid from the atmospheric tower 6 kettle, and an atmospheric tower kettle discharge pump 14 is provided on the atmospheric tower kettle extraction pipeline 13; preferably, the atmospheric tower kettle extraction pipeline 13 is provided with an atmospheric tower flow control valve 15, and the atmospheric tower flow control valve 15 is used to control the material in the atmospheric tower kettle extraction pipeline 13 The flow rate, specifically, by monitoring the liquid level of the atmospheric tower 6 kettle, adjusting the opening of the atmospheric tower flow control valve 15 according to the liquid level of the atmospheric tower 6 kettle, and then controlling the flow rate of the material in the atmospheric tower kettle extraction pipeline 13; the pressurized tower reboiler 9 is heated by steam, specifically, the input end of the pressurized tower reboiler 9 is connected to the steam pipe 16, and the output end of the pressurized tower reboiler 9 is connected to the steam condensate pipe 17, preferably, the steam pipe 16 is provided with a steam pipe valve 18 for controlling the flow rate of the material in the steam pipe 16, and the specific principle is to control the opening of the steam pipe valve 18 by monitoring the temperature of the pressurized tower 1 kettle, and then control the flow rate of the material in the steam pipe 16.

[0036] The atmospheric tower reboiler 10 is heated by the heat from the top of the pressurized tower 1. Specifically, the top of the pressurized tower 1 is connected to the atmospheric tower reboiler 10 through the pressurized tower top extraction pipeline 19, the output pipeline 20 of the atmospheric tower reboiler 10 is connected to the pressurized tower reflux tank 21, the bottom of the pressurized tower reflux tank 21 is connected to the feed preheater 4 through the heat exchange pipeline 22, a pressurized tower reflux pump 23 is provided on the heat exchange pipeline 22, the heat exchange pipeline 22 is also connected to the pressurized tower reflux pipeline 24, the pressurized tower reflux pipeline 24 is connected to the middle and upper part of the pressurized tower 1, preferably, the pressurized tower reflux control valve 25 is provided on the pressurized tower reflux pipeline 24, and the pressurized tower reflux control valve 25 is provided to control the flow rate of the reflux of the pressurized tower 1 , thereby controlling the temperature of the top of the pressure tower 1, specifically, according to the temperature of the top of the pressure tower 1, controlling the opening of the pressure tower reflux control valve 25, adjusting the flow rate of the material in the pressure tower reflux pipeline 24, and then adjusting the temperature of the top of the pressure tower 1; the feed preheater 4 is connected to the pressure tower methanol extraction device; the top of the pressure tower reflux tank 21 is connected to the atmospheric pressure tower methanol extraction device at the top of the atmospheric pressure tower 6 through the gas phase pipeline 26, preferably, the gas phase pipeline 26 is provided with a gas phase regulating valve 27, the gas phase regulating valve 27 is used to adjust the flow rate of the gas phase, and then adjust the pressure of the top of the pressure tower 1, specifically, according to the pressure of the top of the pressure tower 1, controlling the opening of the gas phase regulating valve 27, and then adjusting the pressure of the top of the pressure tower 1.

[0037] Preferably, in order to prevent the salt content in the bottom of the atmospheric tower 6 from saturating and precipitating, a steam condensate feed pipe 28 is provided on one side of the atmospheric tower 6. Preferably, in order to better control the amount of steam condensate entering, a steam condensate control valve 29 is provided on the steam condensate feed pipe 28. The steam condensate control valve 29 controls the flow rate of steam condensate intermittently entering the bottom of the atmospheric tower 6, thereby preventing the salt content from saturating and precipitating.

[0038] In this embodiment, methanol with a concentration of 90-99% can be produced. Compared with the traditional steam stripping process, the steam consumption can be reduced by 30%, the total amount of wastewater after dealcoholization can be greatly reduced, and the energy consumption of the downstream process can be reduced.

[0039] Embodiment 2:

[0040] This embodiment describes the atmospheric tower methanol production device, specifically:

[0041] The atmospheric tower methanol production device includes an atmospheric tower reflux tank 30, which is connected to the top of the atmospheric tower 6 through the atmospheric tower top production pipeline 31, and the above-mentioned gas phase pipeline 26 is connected to the atmospheric tower top production pipeline 31. A primary atmospheric tower condenser 41 is arranged on the atmospheric tower top production pipeline 31, and the primary atmospheric tower condenser 41 is cooled by circulating water. Specifically, the input end of the primary atmospheric tower condenser 41 is connected to the water inlet pipeline 44, and the output end of the primary atmospheric tower condenser 41 is connected to the water outlet pipeline 45. A water outlet control valve 46 is arranged on the water outlet pipeline 45, and the water outlet control valve 46 is used to control the flow rate of circulating water. Specifically, according to the temperature of the material in the atmospheric tower top production pipeline 31, the opening of the water outlet control valve 46 is controlled to control the flow rate of circulating water, thereby controlling the temperature of the tower top material in the atmospheric tower top production pipeline 31.

[0042] The bottom of the atmospheric tower reflux tank 30 is provided with an atmospheric tower methanol extraction pipeline 32, and an atmospheric tower reflux pump 33 is provided on the atmospheric tower methanol extraction pipeline 32. An atmospheric tower product cooler 34 is provided on the atmospheric tower methanol extraction pipeline 32. The atmospheric tower product cooler 34 is cooled by circulating water. Specifically, the input end of the atmospheric tower product cooler 34 is connected to the liquid inlet pipeline 35, and the output end of the atmospheric tower product cooler 34 is connected to the liquid outlet pipeline 36. The liquid outlet pipeline 36 is provided with a There is a liquid outlet pipeline control valve 37, which is used to control the liquid outlet flow rate of the liquid outlet pipeline 36, thereby adjusting the temperature of the methanol product in the atmospheric tower methanol production pipeline 32. Specifically, the opening of the liquid outlet pipeline control valve 37 is controlled by the temperature of the methanol product in the atmospheric tower methanol production pipeline 32, and the temperature of the circulating water is controlled by the liquid outlet flow rate of the liquid outlet pipeline 36, thereby controlling the temperature of the methanol product in the atmospheric tower methanol production pipeline 32; The methanol extraction pipeline 32 is connected to the atmospheric tower reflux pipeline 38, and the atmospheric tower reflux pipeline 38 is connected to the middle and upper part of the atmospheric tower 6. Preferably, the atmospheric tower reflux pipeline 38 is provided with an atmospheric tower reflux control valve 39, and the atmospheric tower reflux control valve 39 is set to control the flow rate of the atmospheric tower 6 reflux, thereby controlling the temperature of the top of the atmospheric tower 6. Specifically, according to the temperature of the top of the atmospheric tower 6, the opening of the atmospheric tower reflux control valve 39 is controlled to adjust the atmospheric tower reflux pipeline 38. 8, through the change of flow rate, affects the temperature of the top of the atmospheric tower 6; more preferably, a liquid level control valve 40 is provided on the atmospheric tower methanol production pipeline 32 to adjust the flow rate of the material in the atmospheric tower methanol production pipeline 32, and then used to control the stability of the liquid level in the atmospheric tower reflux tank 30. Specifically, the opening of the liquid level control valve 40 is controlled by the height of the liquid level in the atmospheric tower reflux tank 30, so as to maintain the stability of the liquid level in the atmospheric tower reflux tank 30.

[0043] More preferably, in order to better realize the treatment of the gas phase, the atmospheric tower top extraction pipeline 31 is connected to the atmospheric tower top extraction pipeline 2 42, and the atmospheric tower top extraction pipeline 2 42 is provided with a secondary atmospheric tower condenser 43; the rising methanol vapor in the atmospheric tower 6 is condensed by the primary atmospheric tower condenser 41 and then flows into the atmospheric tower reflux tank 30, and the uncondensed part of the methanol vapor enters the secondary atmospheric tower condenser 43 for further condensation, and finally the uncondensed non-condensable tail gas goes to other systems; the setting of the secondary atmospheric tower condenser 43 further processes the methanol vapor, increases the recovery rate of methanol, reduces the emission of tail gas, and thus reduces environmental pollution.

[0044] Embodiment three:

[0045] This embodiment describes the pressurized tower methanol extraction device, specifically:

[0046] The pressurized tower methanol production device includes a pressurized tower methanol production pipeline 47 connected to the feed preheater 4, one end of the pressurized tower methanol production pipeline 47 can be connected to the pressurized tower product tank, and a cooler 48 is provided on the pressurized tower methanol production pipeline 47. The cooler 48 cools down by circulating water. The inlet of the cooler 48 is connected to the circulating water inlet pipeline 49, and the outlet of the cooler 48 is connected to the circulating water outlet pipeline 50. Preferably, the circulating water outlet pipeline 50 is provided with an outlet pipeline valve 51, and the outlet pipeline valve 51 is used to control the liquid output in the circulating water outlet pipeline 50, thereby ensuring the temperature of the produced methanol in the pressurized tower methanol production pipeline 47. Specifically, the opening of the outlet pipeline valve 51 is controlled by the temperature of the material in the pressurized tower methanol production pipeline 47, and the temperature of the circulating water is controlled by the flow rate of the liquid output, thereby controlling the temperature of the methanol in the pressurized tower methanol production pipeline 47.

[0047] Furthermore, a pressurizing tower reflux tank liquid level control valve 52 is provided on the pressurizing tower methanol production pipeline 47 at the lower part of the cooler 48, which is used to adjust the flow rate of methanol in the pressurizing tower methanol production pipeline 47, and further control the stability of the liquid level in the pressurizing tower reflux tank 21; specifically, the opening of the pressurizing tower reflux tank liquid level control valve 52 is controlled by the height of the liquid level in the pressurizing tower reflux tank 21, and the flow rate of methanol in the pressurizing tower methanol production pipeline 47 is adjusted, thereby maintaining the stability of the liquid level in the pressurizing tower reflux tank 21.

[0048] Embodiment 4:

[0049] This embodiment provides a specific application scenario, specifically:

[0050] The raw material methanol from outside the boundary area enters the pressure tower feed pump 3, is pressurized to 0.9Mpa (G), and then enters the pressure tower 1 after heat exchange to about 60°C in the feed preheater 4. The pressure tower reboiler 9 is heated by 0.5Mpa (G) saturated steam. The steam volume is evenly controlled by the temperature of the tower bottom of the pressure tower 1 and the steam flow rate. The tower bottom temperature of the pressure tower 1 is controlled at about 127°C. The top vapor phase of the pressure tower 1 enters the atmospheric tower reboiler 10 through self-pressure to provide a heat source for the atmospheric tower 6. The top vapor phase condensate after heat exchange flows into the pressure tower reflux tank 21 by gravity. The uncondensed vapor phase controls the top pressure of the pressure tower 1 to 0.6Mpa (G) through the gas phase regulating valve 27. The remaining gas The liquid is discharged into the primary atmospheric tower condenser 41 for further condensation; the top temperature of the pressure tower 1 is controlled by the opening of the pressure tower reflux control valve 25 to control the reflux flow rate, so that the temperature is stabilized at about 125°C; the remaining materials are controlled by the pressure tower reflux tank level control valve 52 to stabilize the liquid level of the pressure tower reflux tank 21, enter the feed preheater 4 to preheat the raw materials, cool themselves, and then cool to below 50°C through the cooler 48 before being sent to the pressure tower product tank; the pressure tower 1 kettle adopts the pressure tower reboiler circulation pump 11 to increase the circulation driving force of the pressure tower reboiler 9, fully preventing the risk of insufficient siphon capacity caused by excessive salt content, and the pressure tower 1 kettle liquid is controlled by the pressure tower flow control valve 8 to control the liquid level The methanol vapor rising in the atmospheric tower 6 is condensed by the primary atmospheric tower condenser 41 and then flows into the atmospheric tower reflux tank 30 by gravity. The circulating water temperature is controlled below 65.4°C by the outlet water control valve 46. The uncondensed part of the methanol vapor enters the secondary atmospheric tower condenser 43 for further condensation, and the non-condensable tail gas that is not condensed finally goes to other systems. After the methanol liquid in the atmospheric tower reflux tank 30 is pressurized to 0.5Mpa(G) by the atmospheric tower reflux pump 33, a part of it is returned to the atmospheric tower 6 as reflux liquid after the flow rate is controlled by the atmospheric tower reflux control valve 39, and a part of it is controlled by the liquid level control valve 40 to stabilize the liquid level of the atmospheric tower reflux tank 30 and to be frequently The product cooler 34 of the pressure tower cools down the temperature to about 50°C and then is extracted to the atmospheric tower product storage tank; the atmospheric tower 6 kettle is heated by a forced circulation thermal siphon reboiler, and the atmospheric tower reboiler circulation pump 12 is used to increase the driving force for the circulating liquid to prevent insufficient mass transfer driving force due to excessive salt content; the atmospheric tower reboiler 10 is heated by methanol vapor from the top of the pressure tower 1, and at the same time, in order to prevent the saturation precipitation of salt content, the kettle of the atmospheric tower 6 controls the flow rate of steam condensate to intermittently enter the kettle of the atmospheric tower 6 through the steam condensate control valve 29; the kettle liquid of the atmospheric tower 6 is pressurized by the atmospheric tower kettle discharge pump 14, and the atmospheric tower flow control valve 15 controls the atmospheric tower 6 kettle liquid level to about 50% before it is extracted to the next section.

[0051] In the case of this embodiment, the purity of the obtained methanol product is ≥95%, and the steam consumption is about 280 kg steam / t mother liquor.

[0052] In summary, due to the adoption of the above-mentioned technical scheme, the present application changes the traditional glycine centrifugal mother liquor stripping process, adopts double towers in series to recover methanol, the first pressure tower adopts pressurized operation, and the second atmospheric pressure tower adopts atmospheric pressure operation, and the high-temperature methanol vapor at the top of the pressure tower provides a heat source for the atmospheric pressure tower reboiler, realizing the thermal coupling process of the double tower operation, which greatly reduces the heat consumption; at the same time, the high-temperature methanol liquid extracted from the top of the pressure tower is used to preheat the raw material, further saving steam and reducing product energy consumption; and the present application only needs to set up a cooling system at the top of the atmospheric pressure tower, which simplifies the structure of the equipment and reduces the manufacturing cost.

[0053] In addition, this application also has the following advantages:

[0054] 1. Methanol with a concentration of 90-99% can be produced;

[0055] 2. Compared with the traditional steam stripping process, the steam consumption can be reduced by 30%;

[0056] 3. Compared with the traditional single-tower stripping process, the total amount of wastewater after dealcoholization is greatly reduced and the energy consumption of the downstream process is reduced.

[0057] The above-mentioned devices, connection relationships, etc. that are not specifically described belong to the prior art and will not be described in detail in the present utility model.

[0058] The preferred embodiments of the present application are described in detail above in conjunction with the accompanying drawings; however, the present application is not limited to the specific details in the above embodiments. Within the technical concept of the present application, a variety of simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the protection scope of the present application.

[0059] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the various possible combinations of this application will not be described separately.

[0060] In addition, the various implementation modes of the present application may be arbitrarily combined, and as long as they do not violate the concept of the present application, they should also be regarded as the contents disclosed in the present application.

Claims

1. A glycine centrifugal mother liquor recovery device, comprising a pressure tower (1), a feed pipeline (2) is arranged on one side of the pressure tower (1), and a feed preheater (4) is arranged on the feed pipeline (2), characterized in that: The pressure tower (1) is connected to the atmospheric tower (6); the lower parts of the pressure tower (1) and the atmospheric tower (6) are respectively connected to a pressure tower reboiler (9) and an atmospheric tower reboiler (10); the top of the pressure tower (1) is connected to the atmospheric tower reboiler (10) via a pressure tower top extraction pipeline (19); the output pipeline (20) of the atmospheric tower reboiler (10) is connected to a pressure tower reflux tank (21); and the pressure tower reflux tank (21) is connected to the pressure tower reboiler (10). The bottom of the pressure tower (1) is connected to the feed preheater (4) through a heat exchange pipeline (22), the heat exchange pipeline (22) is also connected to the pressure tower reflux pipeline (24), the pressure tower reflux pipeline (24) is connected to the middle and upper part of the pressure tower (1), and the feed preheater (4) is connected to the pressure tower methanol extraction device; the top of the pressure tower reflux tank (21) is connected to the atmospheric pressure tower methanol extraction device at the top of the atmospheric pressure tower (6) through a gas phase pipeline (26).

2. A glycine centrifugal mother liquor recovery device according to claim 1, characterized in that: The atmospheric tower methanol extraction device comprises an atmospheric tower reflux tank (30), the atmospheric tower reflux tank (30) is connected to the top of an atmospheric tower (6) through an atmospheric tower top extraction pipeline (31), a primary atmospheric tower condenser (41) is arranged on the atmospheric tower top extraction pipeline (31), an atmospheric tower methanol extraction pipeline (32) is arranged at the bottom of the atmospheric tower reflux tank (30), an atmospheric tower product cooler (34) is arranged on the atmospheric tower methanol extraction pipeline (32), the atmospheric tower methanol extraction pipeline (32) is connected to an atmospheric tower reflux pipeline (38), and the atmospheric tower reflux pipeline (38) is connected to the middle and upper part of the atmospheric tower (6).

3. A glycine centrifugal mother liquor recovery device according to claim 2, characterized in that: The atmospheric tower top extraction pipeline (31) is connected to the atmospheric tower top extraction pipeline 2 (42), and the atmospheric tower top extraction pipeline 2 (42) is provided with a secondary atmospheric tower condenser (43).

4. A glycine centrifugal mother liquor recovery device according to claim 3, characterized in that: The pressurized tower methanol extraction device comprises a pressurized tower methanol extraction pipeline (47) connected to a feed preheater (4), and a cooler (48) is arranged on the pressurized tower methanol extraction pipeline (47).

5. A glycine centrifugal mother liquor recovery device according to claim 1, characterized in that: A pressure tower reboiler circulation pump (11) is provided at the lower part of the pressure tower reboiler (9).

6. A glycine centrifugal mother liquor recovery device according to claim 1, characterized in that: An atmospheric tower reboiler circulation pump (12) is provided at the lower part of the atmospheric tower reboiler (10).

7. A glycine centrifugal mother liquor recovery device according to claim 1, characterized in that: A steam condensate feed pipeline (28) is provided on one side of the atmospheric pressure tower (6).

8. A glycine centrifugal mother liquor recovery device according to claim 4, characterized in that: The atmospheric tower methanol extraction pipeline (32) is provided with a liquid level control valve (40); the pressurized tower methanol extraction pipeline (47) is provided with a pressurized tower reflux tank liquid level control valve (52).

9. The glycine centrifugal mother liquor recovery device according to claim 1, characterized in that: The pressurizing tower reflux pipeline (24) is provided with a pressurizing tower reflux control valve (25).

10. A glycine centrifugal mother liquor recovery device according to claim 2, characterized in that: The atmospheric tower reflux pipeline (38) is provided with an atmospheric tower reflux control valve (39).

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