An apparatus for reducing solvent decomposition during maleic anhydride analysis.

Abstract

A device for reducing solvent decomposition during maleic anhydride desorption, relating to the field of fine chemical technology, includes a desorption tower reboiler. A steam pipeline is connected to one side of the upper end of the reboiler, and a desuperheater is installed on the steam pipeline. A water inlet pipeline is connected to the desuperheater. A pressure regulating valve and a pressure measuring instrument are installed on the steam pipeline at the front end of the desuperheater. The opening of the pressure regulating valve is adjusted by a pressure controller, and the pressure controller is electrically connected to the pressure measuring instrument. The technical solution of this invention achieves reasonable control of the solvent heating temperature in the desorption tower reboiler by adjusting and controlling the pressure and temperature of the heating steam entering the desorption tower reboiler, thereby avoiding or reducing the problem of solvent decomposition caused by localized overheating.

Description

Technical Field

[0001] This utility model relates to the field of fine chemical technology, specifically to a device for reducing solvent decomposition during maleic anhydride analysis. Background Technology

[0002] Since 2010, the development of my country's biodegradable new materials industry has driven the expansion of the "maleic anhydride-BDO-biodegradable new materials" industrial chain. The n-butane oxidation solvent absorption process, due to its low energy consumption, environmental friendliness, and economic efficiency, has replaced the mainstream benzene oxidation water absorption process in China, becoming the mainstream technology for the maleic anhydride industry. The maleic anhydride solvent desorption process is a crucial step in maleic anhydride production. This step not only affects the maleic anhydride yield but also the solvent decomposition, which is a key factor influencing the overall operating cycle and economic efficiency of the plant.

[0003] In process design, to reduce overall energy consumption, a turbine driving an air compressor often extracts 3.5 MPa steam in the middle section to heat the solvent to 192-194℃, allowing the solvent that has absorbed maleic anhydride to evaporate as much of the maleic anhydride as possible under vacuum conditions. However, because the steam extracted by the turbine is superheated, its pressure is stable but its temperature is higher than the steam saturation temperature, typically between 245-280℃. This superheated steam can locally heat the solvent to above 220℃. Due to the large size of the fixed tube sheet heat exchanger, the solvent temperature measured during rapid material flow is the mixing temperature of the solvent in its flowing state. The locally high-temperature solvent is difficult to measure, creating an uncontrollable factor in actual temperature operation. This locally high-temperature solvent accelerates decomposition, and the resulting phthalic anhydride-like substances clog equipment and pipelines, requiring periodic shutdowns of the entire unit for cleaning, affecting the long-term operation of the unit. Utility Model Content

[0004] In view of the shortcomings of the prior art, the purpose of this utility model is to provide a device for reducing solvent decomposition during maleic anhydride analysis, which can solve the above technical problems.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] An apparatus for reducing solvent decomposition during maleic anhydride desorption includes a desorption tower reboiler. A steam pipeline is connected to one side of the upper end of the reboiler. A desuperheater is installed on the steam pipeline, and a water inlet pipeline is connected to the desuperheater. A pressure regulating valve and a pressure measuring instrument are installed on the steam pipeline at the front end of the desuperheater. The opening of the pressure regulating valve is adjusted by a pressure controller, which is electrically connected to the pressure measuring instrument. A thermometer and a flow valve are installed on the steam pipeline at the rear end of the desuperheater. The flow valve controls the steam flow rate after desuperheating and depressurization via the temperature controller. A flow valve is installed on the water inlet pipeline, which controls the water flow rate via a temperature controller, which is electrically connected to the thermometer. The top of the reboiler is connected to the desorption tower via a discharge pipeline, which is equipped with a thermometer and electrically connected to the temperature controller.

[0007] Preferably, a feed line is connected to the bottom of the reboiler of the desorption tower, and a drain line is connected to one side of the lower end of the reboiler of the desorption tower.

[0008] Preferably, the top of the desorption tower is connected to a finished product pipeline, and the bottom is connected to a reflux pipeline. The other end of the reflux pipeline is connected to the feed pipeline at the bottom of the desorption tower reboiler, and a circulation pump is provided on the reflux pipeline.

[0009] Preferably, a thermometer is provided at the top of the reboiler of the analytical column.

[0010] Compared with the prior art, the beneficial effects of this utility model are as follows: The technical solution of this utility model can control the steam temperature from the source, thereby accurately controlling the temperature of the maleic anhydride-containing solvent heated by the reboiler of the stripping tower. According to the needs of the maleic anhydride stripping operation, the steam source temperature is controlled within a controllable range, and the heat exchange area of ​​the stripping tower reboiler is appropriately increased to compensate for the impact of the decrease in steam source temperature on the heating rate of the maleic anhydride-containing solvent. Thus, under the condition that the heating rate is not affected, the situation of large-scale solvent decomposition caused by local high temperature of the solvent due to high steam source temperature is avoided. This reduces the by-product entrainment in the maleic anhydride product distillation process, avoids the process difficulty of solvent cleaning in the later process, solves the equipment and pipeline blockage caused by the accumulation of phthalic anhydride substances, enables the long-term operation of the device, saves solvent, and improves the maleic anhydride product yield. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0012] Figure 1This is a schematic diagram of the overall structure of this utility model.

[0013] Explanation of reference numerals in the attached figures:

[0014] 1-Reboiler of the stripping tower, 2-Steam line, 3-Desuperheater, 4-Water inlet line, 5-Pressure regulating valve, 6-Pressure measuring instrument, 7-Pressure controller, 8-Thermometer 1, 9-Flow valve 1, 10-Temperature controller 1, 11-Flow valve 2, 12-Temperature controller 2, 13-Discharge line, 14-Stripping tower, 15-Thermometer 2, 16-Inlet line, 17-Drainage line, 18-Finished product line, 19-Reflux line, 20-Circulation pump, 21-Thermometer 3. Detailed Implementation

[0015] The invention will now be described in detail with reference to the accompanying drawings, by way of example. Obviously, the described embodiments are only some embodiments of the invention, and not all embodiments.

[0016] like Figure 1 As shown, this utility model discloses a device for reducing solvent decomposition during maleic anhydride desorption, including a desorption tower reboiler 1. A steam pipeline 2 is connected to one side of the upper end of the desorption tower reboiler 1. A desuperheater 3 is installed on the steam pipeline 2, and a water inlet pipeline 4 is connected to the desuperheater 3. A pressure regulating valve 5 and a pressure measuring instrument 6 are installed on the steam pipeline 2 at the front end of the desuperheater 3. The opening of the pressure regulating valve 5 is adjusted by a pressure controller 7, and the pressure controller 7 is electrically connected to the pressure measuring instrument 6. In specific application, superheated steam is introduced into the inlet end of the steam pipeline 2. The pressure measuring instrument 6 transmits the detected steam pressure signal to the pressure controller 7. According to the pressure design requirements, the pressure controller 7 controls the opening of the pressure regulating valve 5 to achieve pressure reduction. The depressurized steam enters the desuperheater 3. At the same time, the boiler water introduced into the water inlet pipeline 4 also enters the desuperheater 3 to cool the depressurized steam. Finally, the depressurized steam enters the desorption tower reboiler 1 to heat the material.

[0017] The steam pipeline 2 at the rear end of the desuperheater 3 is equipped with a thermometer 8 and a flow valve 9. The flow valve 9 controls the steam flow rate after desuperheating and pressure reduction through a temperature controller 10. The water inlet pipeline 4 is equipped with a flow valve 11. The flow valve 11 controls the water flow rate through a temperature controller 12. The temperature controller 12 is electrically connected to the thermometer 8. The top of the reboiler 1 of the desorption tower is connected to the desorption tower 14 through a discharge pipeline 13. The discharge pipeline 13 is equipped with a thermometer 15. The thermometer 15 is electrically connected to the temperature controller 10. In this embodiment, thermometer 8 is used to detect the temperature of the steam after de-cooling and depressurization. If the temperature is high, thermometer 8 will transmit the temperature detection signal to temperature controller 12. Temperature controller 12 controls the opening of flow valve 11 and controls the steam temperature by adjusting the water flow rate. Thermometer 15 is used to detect the temperature of the material after steam heating. If the temperature is high, thermometer 15 will transmit the temperature detection signal to temperature controller 10. Temperature controller 10 controls the opening of flow valve 9 and controls the material temperature by adjusting the steam flow rate.

[0018] The bottom of the reboiler 1 of the stripping column is connected to a feed line 16, and the mixture of maleic anhydride and solvent enters the tubes of the reboiler 1 of the stripping column from the feed line 16; a drain line 17 is connected to one side of the lower end of the reboiler 1 of the stripping column, and the condensate generated after steam heating is discharged through the drain line 17.

[0019] The top of the analytical column 14 is connected to a finished product pipeline 18, and the bottom is connected to a reflux pipeline 19. The other end of the reflux pipeline 19 is connected to the feed pipeline 16 at the bottom of the analytical column reboiler 1. A circulation pump 20 is installed on the reflux pipeline 19. The heated material enters the analytical column 14 for separation. The separated maleic anhydride is discharged through the finished product pipeline 18. The unseparated material is pumped through the reflux pipeline 19 to the feed pipeline 16 and re-enters the analytical column reboiler 1 for heating.

[0020] The top of the reboiler 1 of the analytical tower is equipped with thermometer 21, which is used to detect the temperature of the material in the tube and to calibrate whether the temperature detected by thermometer 215 is accurate.

[0021] During operation, superheated steam is cooled and depressurized by pressure regulating valve 5 and water before entering the reboiler 1 of the desorption tower to heat the material in the tubes of the reboiler 1. The heated material enters the desorption tower 14 for separation. The separated maleic anhydride is discharged through the finished product pipeline 18, while the unseparated material is returned to the feed pipeline 16 through the reflux pipeline 19 and re-enters the reboiler 1 of the desorption tower for heating.

[0022] Reducing solvent decomposition in the maleic anhydride stripping process has several advantages. First, it lowers solvent consumption, leading to economic benefits. Second, it reduces byproducts from solvent decomposition, improving product quality and ensuring long-term stable operation of the solvent purification process. This avoids the need for complete line shutdowns for cleaning, resulting in cleaner solvents that are more conducive to the absorption of maleic anhydride in the absorption tower, thus increasing the maleic anhydride yield. Furthermore, the reduced decomposition products in the solvent decrease the amount of wastewater generated for solvent cleaning, lowering the organic content and simplifying wastewater treatment, which is beneficial for the environmentally friendly operation of the plant.

[0023] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and application concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A device for reducing solvent decomposition in a maleic anhydride resolution process, comprising a resolution column reboiler (1), characterized in that: A steam pipeline (2) is connected to one side of the upper end of the reboiler (1) of the desorption tower. A desuperheater (3) is provided on the steam pipeline (2). A water inlet pipeline (4) is connected to the desuperheater (3). A pressure regulating valve (5) and a pressure measuring instrument (6) are provided on the steam pipeline (2) at the front end of the desuperheater (3). The opening of the pressure regulating valve (5) is adjusted by a pressure controller (7). The pressure controller (7) is electrically connected to the pressure measuring instrument (6). A thermometer (8) and a flow valve (9) are provided on the steam pipeline (2) at the rear end of the desuperheater (3). The flow valve 1 (9) controls the steam flow rate after de-cooling and depressurization through the temperature controller 1 (10); the water inlet pipeline (4) is equipped with a flow valve 2 (11), which controls the water flow rate through the temperature controller 2 (12), and the temperature controller 2 (12) is electrically connected to the thermometer 1 (8); the top of the reboiler (1) of the desorption tower is connected to the desorption tower (14) through the discharge pipeline (13), and the discharge pipeline (13) is equipped with a thermometer 2 (15), which is electrically connected to the temperature controller 1 (10).

2. The apparatus for reducing solvent decomposition in a succinic acid resolution process of claim 1, wherein: The bottom of the reboiler (1) of the desorption tower is connected to a feed line (16), and the lower end of the reboiler (1) is connected to a drain line (17).

3. The apparatus for reducing solvent decomposition in a succinic acid resolution process of claim 2, wherein: The top of the analytical tower (14) is connected to the finished product pipeline (18), and the bottom is connected to the reflux pipeline (19). The other end of the reflux pipeline (19) is connected to the feed pipeline (16) at the bottom of the analytical tower reboiler (1). A circulation pump (20) is provided on the reflux pipeline (19).

4. The apparatus for reducing solvent decomposition in a succinic acid resolution process of claim 1, wherein: The thermometer three (21) is installed at the top of the reboiler (1) of the analytical column.

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