Apparatus and method for automatic control of production of hydrogen chloride organic solution in multistage falling film low temperature absorption method

Abstract

The application provides a device and method for automatically controlling production of hydrogen chloride organic solution in a multistage falling film low-temperature absorption method, which comprises a hydrogen chloride cooler, a first falling film absorber, a second falling film absorber, an absorption tower and a tail gas cooler connected in sequence through a gas phase pipeline, a liquid outlet at the bottom of a solvent storage tank is connected to a liquid phase inlet of the absorption tower through a solvent delivery pipe, and a third flow regulating valve, a solvent cooler and a solvent delivery pump are arranged on the solvent delivery pipe. The application overcomes the shortcomings of the conventional process, such as difficulty in controlling absorption temperature, low absorption efficiency, poor uniformity of product concentration, difficulty in controlling impurity content and the like, and can realize continuous and stable production of qualified products meeting the requirements of the pharmaceutical intermediate industry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical industry and relates to a device and a method for automatically controlling production of hydrogen chloride organic solution in a multistage falling film low-temperature absorption method. BACKGROUND

[0002] Hydrogen chloride organic solution is widely used in the pharmaceutical intermediate industry, is often used for acetal reaction to protect aldehyde groups and anhydrous reaction to add acid, and is a raw material for preparing various pharmaceutical intermediates. At present, there is no perfect hydrogen chloride organic solution product system in the industry, and there are few domestic enterprises producing hydrogen chloride organic solution. The direct passing method of directly passing hydrogen chloride gas into an organic solvent is adopted, and even some customers directly purchase steel bottle hydrogen chloride gas for on-site preparation. The production process is still in a relatively extensive stage, and the degree of automation is low. There are problems such as discontinuous production, great operation difficulty, great manual labor intensity, poor on-site environment and the like. SUMMARY

[0003] The application aims at the deficiencies in the prior art and provides a device and a method for automatically controlling production of hydrogen chloride organic solution in a multistage falling film low-temperature absorption method, which are simple in structure and easy to implement.

[0004] The device for automatically controlling production of hydrogen chloride organic solution in a multistage falling film low-temperature absorption method comprises, which are connected in sequence through a gas phase pipeline, a hydrogen chloride cooler, a first falling film absorber, a second falling film absorber, an absorption tower and a tail gas cooler. A liquid outlet at the bottom of a solvent storage tank is connected to a liquid inlet of the absorption tower through a solvent delivery pipe. A third flow regulating valve, a solvent cooler and a solvent delivery pump are arranged on the solvent delivery pipe. A liquid outlet of the absorption tower is connected to a liquid inlet pipe of the second falling film absorber and a discharge pipe of the absorption tower. The liquid inlet pipe of the second falling film absorber is connected to a liquid inlet of the second falling film absorber. A second discharge valve is arranged on the discharge pipe of the absorption tower. The liquid inlet pipe of the second falling film absorber is connected to a second circulation pipe. A second flow regulating valve and a second circulation pump are arranged on the second circulation pipe. A liquid outlet of the second falling film absorber is connected to a discharge pipe of the second falling film absorber and a liquid inlet pipe of the first falling film absorber. The liquid inlet pipe of the first falling film absorber is connected to a liquid inlet of the first falling film absorber. A first discharge valve is arranged on the discharge pipe of the second falling film absorber. The liquid inlet pipe of the first falling film absorber is connected to a first circulation pipe. A first flow regulating valve, an online concentration analyzer, a feeding valve and a first circulation pump are arranged on the first circulation pipe. The first falling film absorber is connected to a first circulation tank through a discharge pipe of the first falling film absorber. A product delivery pipe is connected to the first circulation pipe between the feeding valve and the first circulation pump. A discharge valve is arranged on the product delivery pipe.

[0005] The hydrogen chloride cooler front end is provided with a hydrogen chloride cut-off valve on the gas phase pipeline, and the hydrogen chloride cooler and the first falling film absorber are provided with a hydrogen chloride regulating valve on the gas phase pipeline.

[0006] The hydrogen chloride cooler, the first falling film absorber, the second falling film absorber, the solvent cooler and the tail gas cooler are connected with the water chilling unit through temperature regulating valves.

[0007] The tail gas cooler is connected with a tail gas conveying pipe, the tail gas conveying pipe is provided with a pressure regulating valve, the tail gas conveying pipe is connected with a tail gas discharge pipe and a tail gas water washing pipe, the tail gas water washing pipe is connected with a tail gas water washing tower through a tail gas water washing valve, and the tail gas conveying pipe is connected with a tail gas chimney through a tail gas emptying valve.

[0008] The solvent storage tank is provided with a solvent liquid inlet pipe, and the solvent liquid inlet pipe is provided with a solvent feeding valve.

[0009] The hydrogen chloride cut-off valve, the hydrogen chloride regulating valve, the first flow regulating valve, the second flow regulating valve, the third flow regulating valve, the temperature regulating valve, the online concentration analyzer, the feeding valve, the discharging valve, the first material stringing valve, the first material discharging valve, the second material stringing valve, the second material discharging valve, the second circulating tank, the solvent feeding valve, the pressure regulating valve, the tail gas emptying valve, the tail gas water washing valve, the first circulating pump, the second circulating pump and the solvent conveying pump are connected with a DCS control system, and the DCS control system is installed on an industrial computer.

[0010] The method for automatically controlling production of hydrogen chloride organic solution in the multi-stage falling film low-temperature absorption method has the following working process:

[0011] Step one: feeding

[0012] (1) Open the solvent feed valve to send the organic solvent into the solvent tank; (2) When the liquid level of the solvent tank reaches 80%, start the solvent delivery pump and open the third flow regulating valve, and the organic solvent is cooled by the solvent cooler 28 and enters the absorption tower through the solvent delivery pipe; (3) Open the second material valve, close the second discharge valve, open the first discharge valve, close the first material valve, and the organic solvent enters the second falling film absorber through the second falling film absorber liquid inlet pipe, and enters the second circulating tank through the second falling film absorber discharge pipe; (4) When the liquid level of the second circulating tank reaches 80%, open the first material valve, close the first discharge valve, and the organic solvent enters the first falling film absorber through the first falling film absorber liquid inlet pipe, and enters the first circulating tank through the first falling film absorber discharge pipe; (5) When the liquid level of the first circulating tank reaches 80%, open the first discharge valve and close the first material valve; open the second discharge valve and close the second material valve; (6) Start the first circulating pump and the second circulating pump, and control the circulating liquid flow through the first flow regulating valve, the second flow regulating valve and the third flow regulating valve; open the hydrogen chloride cut-off valve to introduce hydrogen chloride gas, and control the hydrogen chloride flow through the hydrogen chloride regulating valve.

[0013] Step two: absorption

[0014] (1) Control the pressure in the appropriate range through the pressure regulating valve; (2) Control the temperature in the first falling film absorber, the second falling film absorber and the absorption tower in the appropriate range through the temperature regulating valve; control the outlet temperature of the hydrogen chloride cooler in the appropriate range through the temperature regulating valve 6; (3) Open the tail gas exhaust valve and close the tail gas water washing valve.

[0015] Step three: discharge

[0016] (1) Determine the absorption endpoint by the concentration value displayed by the online concentration analyzer, and reduce the hydrogen chloride flow through the hydrogen chloride regulating valve when the displayed concentration value reaches the required range; (2) Open the discharge valve and close the feeding valve, and transport the hydrogen chloride organic solution product through the product delivery pipe; (3) When the liquid level of the first circulating tank reaches 20%, open the feeding valve and close the discharge valve; (4) Perform step one to absorb the next round.

[0017] Step four: emergency

[0018] (1) When the system fails, close the hydrogen chloride cut-off valve and fill nitrogen into the system; (2) Open the tail gas water washing valve and close the tail gas exhaust valve, and ensure that the tail gas meets the standard under fault condition through the tail gas water washing tower.

[0019] Advantages of the present application:

[0020] The present application overcomes the shortcomings of traditional process, such as difficult control of absorption temperature, low absorption efficiency, poor product concentration uniformity, and difficult control of impurity content, and can realize continuous and stable production of qualified products meeting the requirements of the pharmaceutical intermediate industry.

[0021] The present application realizes remote monitoring and control of all key control points in the production process of hydrogen chloride organic solution by multistage falling film low-temperature absorption method through automatic control technology, realizes programmed automatic control of the whole process, and achieves the purpose of continuous and stable production of qualified products through automatic control, while the operation is simple and the control is convenient, the labor intensity is reduced, and the on-site production environment is improved. The problems of low automation degree, discontinuous production, high operation difficulty, high labor intensity, and poor on-site environment in the current industry are solved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structural schematic diagram of the present application;

[0023] 1-hydrogen chloride shut-off valve, 2-hydrogen chloride regulating valve, 3-first flow regulating valve, 4-second flow regulating valve, 5-third flow regulating valve, 6-temperature regulating valve, 07-gas phase pipeline, 08-solvent conveying pipe, 09-second falling film absorber liquid inlet pipe, 10-online concentration analyzer, 11-feeding valve, 12-discharging valve, 13-first stringing valve, 14-first discharging valve, 15-second stringing valve, 16-second discharging valve, 17-hydrogen chloride cooler, 18-first falling film absorber, 19-second falling film absorber, 20-absorption tower, 21-first circulating tank, 22-first circulating pump, 23-second circulating tank, 24-second circulating pump, 25-solvent storage tank, 26-solvent feeding valve, 27-solvent conveying pump, 28-solvent cooler, 29-tail gas cooler, 30-pressure regulating valve, 31-tail gas chimney, 32-tail gas emptying valve, 33-tail gas water washing valve, 34-tail gas water washing tower, 35-tail gas conveying pipe, 36-tail gas discharge pipe, 37-tail gas water washing pipe, 38-absorption tower discharging pipe, 39-second circulating pipe, 40-second falling film absorber discharging pipe, 41-first falling film absorber liquid inlet pipe, 42-first circulating pipe, 43-first falling film absorber discharging pipe, 44-product conveying pipe, 45-solvent liquid inlet pipe. DETAILED DESCRIPTION

[0024] The present application will be further described in detail below in combination with specific examples and drawings, but the embodiments of the present application are not limited to this.

[0025] As Figure 1As shown, the device for automatically controlling the production of hydrogen chloride organic solution in a multi-stage falling film low-temperature absorption method comprises, in sequence through a gas phase pipeline, a hydrogen chloride cooler 17, a first falling film absorber 18, a second falling film absorber 19, an absorption tower 20, and a tail gas cooler 29. The liquid phase inlet of the absorption tower 20 is connected to the liquid outlet at the bottom of a solvent storage tank 25 through a solvent delivery pipe 8, and the solvent delivery pipe 8 is provided with a third flow regulating valve 5, a solvent cooler 28, and a solvent delivery pump 27. The liquid phase outlet of the absorption tower 20 is connected to a second falling film absorber liquid inlet pipe 9 and an absorption tower discharge pipe 38. The second falling film absorber liquid inlet pipe 9 is connected to the liquid phase inlet of the second falling film absorber 19, and the absorption tower discharge pipe 38 is connected to the solvent storage tank 25. The second falling film absorber liquid inlet pipe 9 is provided with a second material stringing valve 15, and the absorption tower discharge pipe 38 is provided with a second discharge valve 16. The second falling film absorber liquid inlet pipe 9 is connected to a second circulation pipe 39, and the second circulation pipe 39 is provided with a second flow regulating valve 4 and a second circulation pump 24. The liquid phase outlet of the second falling film absorber 19 is connected to a second falling film absorber discharge pipe 40 and a first falling film absorber liquid inlet pipe 41. The first falling film absorber liquid inlet pipe 41 is connected to the liquid phase inlet of the first falling film absorber 18, and the first falling film absorber liquid inlet pipe 41 is provided with a first material stringing valve 13. The second falling film absorber discharge pipe 40 is provided with a first discharge valve 14. The first falling film absorber liquid inlet pipe 41 is connected to a first circulation pipe 42, and the first circulation pipe 42 is provided with a first flow regulating valve 3, an online concentration analyzer 10, a feeding valve 11, and a first circulation pump 22. The first falling film absorber 18 is connected to a first circulation tank 21 through a first falling film absorber discharge pipe 43. The first circulation pipe 42 between the feeding valve 11 and the first circulation pump 22 is connected to a product delivery pipe 44, and the product delivery pipe 44 is provided with a discharge valve 12.

[0026] A hydrogen chloride cut-off valve 1 is arranged on the gas phase pipeline at the front end of the hydrogen chloride cooler 17, and a hydrogen chloride regulating valve 2 is arranged on the gas phase pipeline between the hydrogen chloride cooler 17 and the first falling film absorber.

[0027] The hydrogen chloride cooler 17, the first falling film absorber 18, the second falling film absorber 19, the solvent cooler 28, and the tail gas cooler 29 are all connected to a cold water unit through temperature regulating valves.

[0028] The tail gas cooler 29 is connected to a tail gas delivery pipe 35, and the tail gas delivery pipe 35 is provided with a pressure regulating valve 30. The tail gas delivery pipe 35 is connected to a tail gas discharge pipe 36 and a tail gas water washing pipe 37. The tail gas water washing pipe 37 is connected to a tail gas water washing tower 34 through a tail gas water washing valve 33. The tail gas delivery pipe 35 is connected to a tail gas exhaust valve 32 and a tail gas chimney 31.

[0029] The solvent storage tank 25 is provided with a solvent liquid inlet pipe 45, and the solvent liquid inlet pipe 45 is provided with a solvent feeding valve 26.

[0030] The hydrogen chloride cut-off valve 1, the hydrogen chloride regulating valve 2, the first flow regulating valve 3, the second flow regulating valve 4, the third flow regulating valve 5, the temperature regulating valve 6, the on-line concentration analyzer 10, the feeding valve 11, the discharging valve 12, the first string valve 13, the first discharging valve 14, the second string valve 15, the second discharging valve 16, the second circulating tank 23, the solvent feeding valve 26, the pressure regulating valve 30, the tail gas exhaust valve 32, the tail gas water washing valve 33, the first circulating pump 22, the second circulating pump 24 and the solvent delivery pump 27 are connected with the DCS control system, the DCS control system is installed on the industrial computer, and the above regulating valves in the production device are automatically controlled through the DCS control system and operated through the industrial computer.

[0031] A method for automatically controlling production of hydrogen chloride organic solution in a multi-stage falling film low-temperature absorption method, and a working process is as follows:

[0032] Step one: feeding

[0033] (1) The solvent feeding valve 26 is opened to send the organic solvent into the solvent storage tank 25; (2) when the liquid level of the solvent storage tank 25 reaches 80%, the solvent delivery pump 27 is started and the third flow regulating valve 5 is opened, the organic solvent is cooled through the solvent cooler 28 and enters the absorption tower 20 through the solvent delivery pipe 8; (3) the second string valve 15 is opened, the second discharging valve 16 is closed, the first discharging valve 14 is opened, and the first string valve 13 is closed, the organic solvent enters the second falling film absorber 19 through the second falling film absorber liquid inlet pipe 9, and enters the second circulating tank 23 through the second falling film absorber discharging pipe 40; (4) when the liquid level of the second circulating tank 23 reaches 80%, the first string valve 13 is opened, the first discharging valve 14 is closed, the organic solvent enters the first falling film absorber 18 through the first falling film absorber liquid inlet pipe 41, and enters the first circulating tank 21 through the first falling film absorber discharging pipe 43; (5) when the liquid level of the first circulating tank 21 reaches 80%, the first discharging valve 14 is opened, the first string valve 13 is closed, the second discharging valve 16 is opened, and the second string valve 15 is closed; (6) the first circulating pump 22 and the second circulating pump 24 are started, and the circulating liquid flow is controlled through the first flow regulating valve 3, the second flow regulating valve 4 and the third flow regulating valve 5; the hydrogen chloride cut-off valve 1 is opened to introduce hydrogen chloride gas, and the hydrogen chloride flow is controlled through the hydrogen chloride regulating valve 2.

[0034] Step two: absorption

[0035] (1) The pressure is controlled in a proper range by the pressure regulating valve 30; (2) The temperature in the first falling film absorber 18, the second falling film absorber 19 and the absorption tower 20 is controlled in a proper range by the temperature regulating valve 6; the temperature at the outlet of the hydrogen chloride cooler 17 is controlled in a proper range by the temperature regulating valve 6; (3) The tail gas exhaust valve 32 is opened and the tail gas water washing valve 33 is closed. The hydrogen chloride gas is absorbed in the first falling film absorber 18, the second falling film absorber 19 and the absorption tower 20.

[0036] Step three: discharging

[0037] (1) The absorption end point is determined by the concentration value displayed by the online concentration analyzer 10, when the displayed concentration value reaches the required range, the hydrogen chloride flow is reduced by the hydrogen chloride regulating valve 2; (2) The discharging valve 12 is opened and the feeding valve 11 is closed, the hydrogen chloride organic solution product is transported out through the product conveying pipe; (3) When the liquid level of the first circulating tank 21 reaches 20%, the feeding valve 11 is opened and the discharging valve 12 is closed; (4) Step one is executed to carry out the next round of absorption.

[0038] Step four: emergency

[0039] (1) When the system fails, the hydrogen chloride cut-off valve 1 is closed, and nitrogen is filled into the system; (2) The tail gas water washing valve 33 is opened and the tail gas exhaust valve 32 is closed, and the tail gas is ensured to meet the standard in the fault state by the tail gas water washing tower 34.

[0040] The valves in the above steps are automatically controlled by the DCS control system, and are operated by the industrial computer.

[0041] The above only describes the preferred embodiments of the present application, but the implementation of the present application is not limited to this. It should be noted that for those skilled in the art, under the technical inspiration provided by the present application, other equivalent variants and improvements can also be made, which can achieve the purpose of the present application, and should be regarded as the protection scope of the present application.

Claims

1. A method for automatically controlling the production of hydrogen chloride organic solution in a multistage falling film low temperature absorption process, characterized in that, This is accomplished by the following apparatus and process: The production apparatus includes a hydrogen chloride cooler (17), a first falling film absorber (18), a second falling film absorber (19), an absorption tower (20), and a tail gas cooler (29) connected in sequence via a gas phase pipeline (7). The liquid phase inlet of the absorption tower (20) is connected to the outlet at the bottom of the solvent storage tank (25) via a solvent delivery pipe (8). The solvent delivery pipe (8) is equipped with a third flow regulating valve (5), a solvent cooler (28), and a solvent delivery pump (27). The liquid phase outlet of the absorption tower (20) is connected to the first... The second falling film absorber inlet pipe (9) and the absorption tower discharge pipe (38) are connected. The second falling film absorber inlet pipe (9) is connected to the liquid phase inlet of the second falling film absorber (19), and the absorption tower discharge pipe (38) is connected to the solvent storage tank (25). A second feed valve (15) is provided on the second falling film absorber inlet pipe (9), and a second discharge valve (16) is provided on the absorption tower discharge pipe (38). The second falling film absorber inlet pipe (9) is connected to the second circulation pipe (39), and a second discharge valve (16) is provided on the second circulation pipe (39). Two flow regulating valves (4) and a second circulation pump (24), the liquid phase outlet of the second falling film absorber (19) is connected to the second falling film absorber feed pipe (40) and the first falling film absorber inlet pipe (41), the first falling film absorber inlet pipe (41) is connected to the liquid phase inlet of the first falling film absorber (18), the first falling film absorber inlet pipe (41) is provided with a first feed valve (13), the second falling film absorber feed pipe (40) is provided with a first feed valve (14); the first falling film absorber inlet pipe ( 41) Connect the first circulation pipe (42), the first circulation pipe (42) is equipped with a first flow regulating valve (3), an online concentration analyzer (10), a feeding valve (11), and a first circulation pump (22), the first falling film absorber (18) is connected to the first circulation tank (21) through the first falling film absorber discharge pipe (43), the first circulation pipe (42) between the feeding valve (11) and the first circulation pump (22) is connected to the product conveying pipe (44), the product conveying pipe (44) is equipped with a discharge valve (12); A hydrogen chloride shut-off valve (1) is provided on the gas phase pipeline at the front end of the hydrogen chloride cooler (17), and a hydrogen chloride regulating valve (2) is provided on the gas phase pipeline between the hydrogen chloride cooler (17) and the first falling film absorber. The hydrogen chloride cooler (17), the first falling film absorber (18), the second falling film absorber (19), the solvent cooler (28), and the tail gas cooler (29) are all connected to the chiller unit through the temperature regulating valve (6). The hydrogen chloride shut-off valve (1), hydrogen chloride regulating valve (2), first flow regulating valve (3), second flow regulating valve (4), third flow regulating valve (5), temperature regulating valve (6), online concentration analyzer (10), feeding valve (11), discharging valve (12), first feed valve (13), first discharge valve (14), second feed valve (15), second discharge valve (16), second circulation tank (23), solvent feed valve (26), pressure regulating valve (30), tail gas vent valve (32), tail gas water washing valve (33), first circulation pump (22), second circulation pump (24), and solvent delivery pump (27) are all connected to the DCS control system, which is installed on an industrial control computer. The production process includes the following steps: Step 1: Feeding Open the solvent feed valve (26) to send the organic solvent into the solvent storage tank (25); when the liquid level in the solvent storage tank (25) reaches 80%, start the solvent delivery pump (27) and open the third flow regulating valve (5). The organic solvent is cooled by the solvent cooler (28) and enters the absorption tower (20) through the solvent delivery pipe (8); open the second feed valve (15), close the second discharge valve (16), open the first discharge valve (14), close the first feed valve (13), and the organic solvent enters the second falling film absorber (19) through the second falling film absorber inlet pipe (9) and enters the second circulation tank (23) through the second falling film absorber discharge pipe (40); when the liquid level in the second circulation tank (23) reaches 80%, open the first feed valve (13). ), close the first discharge valve (14), the organic solvent enters the first falling film absorber (18) through the first falling film absorber inlet pipe (41), and enters the first circulation tank (21) through the first falling film absorber discharge pipe (43); when the liquid level of the first circulation tank (21) reaches 80%, open the first discharge valve (14) and close the first feed valve (13); open the second discharge valve (16) and close the second feed valve (15); start the first circulation pump (22) and the second circulation pump (24), and control the circulation liquid flow rate through the first flow regulating valve (3), the second flow regulating valve (4), and the third flow regulating valve (5); open the hydrogen chloride cut-off valve (1) to introduce hydrogen chloride gas, and control the hydrogen chloride flow rate through the hydrogen chloride regulating valve (2); Step Two: Absorption The pressure is controlled within a suitable range by the pressure regulating valve (30); the temperature inside the first falling film absorber (18), the second falling film absorber (19), and the absorption tower (20) is controlled within a suitable range by the temperature regulating valve (6); the outlet temperature of the hydrogen chloride cooler (17) is controlled within a suitable range by the temperature regulating valve (6); the tail gas vent valve (32) is opened, and the tail gas water washing valve (33) is closed. Step 3: Discharge The absorption endpoint is determined by the concentration value displayed by the online concentration analyzer (10). When the concentration value reaches the range required by the index, the hydrogen chloride flow rate is reduced by the hydrogen chloride regulating valve (2). The discharge valve (12) is opened and the feed valve (11) is closed. The hydrogen chloride organic solution product is transported out through the product conveying pipe. When the liquid level of the first circulation tank (21) reaches 20%, the feed valve (11) is opened and the discharge valve (12) is closed. Step one is executed to carry out the next round of absorption. Step Four: Emergency Response When the system malfunctions, close the hydrogen chloride shut-off valve (1) and charge the system with nitrogen; open the tail gas water washing valve (33), close the tail gas vent valve (32), and ensure that the tail gas meets the standards under the fault condition through the tail gas water washing tower (34).

2. The apparatus for automatically controlling the production of hydrogen chloride organic solution in a multi-stage falling film low-temperature absorption method according to claim 1, characterized in that: The exhaust gas cooler (29) is connected to the exhaust gas delivery pipe (35), and the exhaust gas delivery pipe (35) is equipped with a pressure regulating valve (30). The exhaust gas delivery pipe (35) is connected to the exhaust gas discharge pipe (36) and the exhaust gas water washing pipe (37). The exhaust gas water washing pipe (37) is connected to the exhaust gas water washing tower (34) through the exhaust gas water washing valve (33). The exhaust gas delivery pipe (35) is connected to the exhaust gas chimney (31) through the exhaust gas vent valve (32).

3. The apparatus for automatically controlling the production of hydrogen chloride organic solution in a multi-stage falling film low-temperature absorption method according to claim 1, characterized in that: The solvent storage tank (25) is provided with a solvent inlet pipe (45), and a solvent feed valve (26) is provided on the solvent inlet pipe (45).

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