A reaction device for condensation of aldehydes catalyzed by liquid base

Abstract

The utility model discloses a kind of reaction devices of liquid alkali catalytic aldehyde condensation, including the condensation reaction tower coupling device of lower part connecting aldehyde alkali feed pipe, its tower top outlet is sequentially connected with steam ejector, extraction separation condenser, extractor separator by negative pressure pipe, the oil phase outlet of extractor separator is connected to the upper reflux port of condensation reaction tower coupling device by oil phase backflow pipe;Condensation reaction tower coupling device bottom discharge port is sequentially connected with reaction tower bottom pump, oil alkali separation cooler, oil alkali separator by pipeline, between condensation reaction tower coupling device lower reflux port and reaction tower bottom pump outlet, there is reboiler by pipeline connection, one outlet of oil alkali separator is connected with lye pipe, another outlet is connected product backflow pipe and product lead-out pipe, product backflow pipe connects extractor separator inlet liquid port.The utility model is coupled to the condensation reactor, condensation circulating tower and is reformed, reaches the purpose of simplifying process flow, improving operation flexibility, reducing energy consumption.

Description

Technical Field

[0001] This utility model relates to the technical field of liquid base-catalyzed aldehyde condensation, and more specifically, to a reaction apparatus for liquid base-catalyzed aldehyde condensation. Background Technology

[0002] Aldol condensation refers to the nucleophilic addition of compounds containing active α-hydrogen atoms, such as aldehydes, ketones, carboxylic acids, and esters, to carbonyl compounds under the action of a catalyst to obtain β-hydroxy aldehydes or acids, or further dehydration to obtain α, β-unsaturated aldehydes, ketones, or esters.

[0003] In the aldol condensation reaction described above, the condensation between aldehydes is a crucial step in many production processes. Taking actual production as an example, liquid alkali (NaOH solution) is mixed with the raw aldehyde and then fed into the condensation reactor. After the reaction in the condensation reactor, the product is introduced into a condensation circulation tower. While the reboiler at the bottom of the condensation circulation tower heats the product, a cooling water heat exchanger at the top condenses the water vapor carrying a small amount of the raw aldehyde. A steam ejector then provides negative pressure to pump the condensate to a flash tank for further processing. The oil phase in the flash tank is returned to the condensation tower as reflux, while the aqueous phase is collected for the next stage of processing.

[0004] There are two key points to consider in actual production. First, the water produced in the condensation reaction rapidly dilutes the liquid alkaline solution used as a catalyst. Changes in the concentration of the liquid alkaline solution significantly affect the conversion rate and selectivity of the reaction, not only reducing the yield of the target product but also causing more severe catalyst contamination from the generated acids. Although the process design incorporates a method to maintain the concentration of the liquid alkaline solution in the condensation reactor by replenishing a higher concentration of catalyst, some aldehyde residue remains when the material is withdrawn from the bottom of the reactor. This means that the diluted liquid alkaline solution can still act as a catalyst in the condensation circulation tower, allowing the condensation reaction to continue, leading to an increase in by-products. This should be avoided. Second, the process still consumes a significant amount of cooling and heating energy. Heat consumption mainly includes steam consumption in the reboiler at the bottom of the tower and the steam ejector at the top. Cooling consumption mainly includes cooling water consumed by the condensation tower condenser, condensation wastewater condenser, and condensation tower cooler. Optimization of energy consumption should be sought. Utility Model Content

[0005] To overcome the shortcomings of existing technologies, and taking advantage of the exothermic nature of aldehyde condensation and the different solubilities of aldehydes in water and organic matter, this invention improves upon existing technologies by providing a liquid alkali-catalyzed aldehyde condensation reaction apparatus. This aims to ultimately reduce energy consumption and achieve better process results. By coupling and modifying the condensation reactor and condensation circulation tower, this invention fully utilizes the heat of reaction and product reflux, thereby simplifying the process flow, increasing operational flexibility, and reducing energy consumption.

[0006] The objective of this utility model is achieved through the following technical solution.

[0007] A reaction apparatus for liquid alkali-catalyzed aldehyde condensation includes a condensation reaction tower coupling device with an aldehyde-alkali feed pipe connected to its lower part. The steam outlet at the top of the condensation reaction tower coupling device is sequentially connected to a steam ejector, an extraction separation condenser, and an extraction separator via a negative pressure pipe. The oil phase outlet of the extraction separator is connected to the upper reflux port of the condensation reaction tower coupling device via an oil phase reflux pipe. The bottom outlet of the condensation reaction tower coupling device is sequentially connected to a reaction tower bottom pump, an oil-alkali separation cooler, and an oil-alkali separator via pipelines. A reboiler is connected between the lower reflux port of the condensation reaction tower coupling device and the outlet of the reaction tower bottom pump via a pipeline. One outlet of the oil-alkali separator is connected to an alkali pipe, and the other outlet is connected to a product reflux pipe and a product outlet pipe, respectively. The product reflux pipe connects this outlet to the liquid inlet of the extraction separator.

[0008] Furthermore, the condensation reaction tower coupling device is divided into an upper distillation section and a lower reaction section. The distillation section is equipped with several whole tower plates, which are filled with packing material. The reaction section is equipped with a stirring paddle.

[0009] Furthermore, the radius of the distillation section of the condensation reaction tower coupling device is smaller than the radius of its reaction section, and the distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device, the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights.

[0010] Furthermore, the condensation reaction tower coupling device is formed by coupling a condensation circulation tower and a condensation reactor. The condensation circulation tower is used as a distillation section after removing the lower end cap, and the condensation reactor is used as a reaction section after removing the upper end cap.

[0011] Compared with the prior art, the beneficial effects of the technical solution of this utility model are:

[0012] This invention couples the condensation reactor and condensation circulation tower in the original process. By modifying the coupling of the aldehyde condensation device, the process flow is shortened, thereby reducing pipeline heat loss, fully utilizing the exothermic reaction to distill off the generated water, and maintaining the catalyst concentration. Simultaneously, the generated product is used to extract and recover the distilled raw material, which is then refluxed back into the tower as cooling energy. This complements the heat provided by the reboiler at the bottom of the tower, increasing operational flexibility and saving energy.

[0013] Compared with the original process and equipment, this utility model shortens the process flow, makes full use of reaction heat and product reflux, improves the operational flexibility of the device, and more stably controls the concentration of liquid alkaline catalyst while saving energy. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the reaction apparatus for liquid base-catalyzed aldehyde condensation according to this invention.

[0015] Figure reference numerals: 1-Condensation reaction tower coupling device, 2-Agitator, 3-Tower plate, 4-Reboiler, 5-Reaction tower bottom pump, 6-Oil-alkali separator, 7-Oil-alkali separation cooler, 8-Extraction separator, 9-Extraction separation condenser, 10-Steam ejector, 11-Aldehyde-alkali feed pipe, 12-Aldehyde-alkali discharge pipe, 13-Reboiler reflux pipe, 14-Aldehyde-alkali separation pipe, 15-Alkali pipe, 16-Product reflux pipe, 17-Steam pipe, 18-Negative pressure pipe, 19-Oil phase reflux pipe, 20-Aqueous phase collection pipe, 21-Product outlet pipe. Detailed Implementation

[0016] The present invention will now be further described with reference to the accompanying drawings.

[0017] like Figure 1 As shown, this utility model proposes a reaction device for liquid alkali-catalyzed aldehyde condensation, including a condensation reaction tower coupling device 1. The lower part of the condensation reaction tower coupling device 1 is connected to an aldehyde-alkali feed pipe 11. The steam outlet at the top of the condensation reaction tower coupling device 1 is sequentially connected to a steam ejector 10, an extraction separation condenser 9, and an extraction separator 8 via a negative pressure pipe 18. The oil phase outlet of the extraction separator 8 is connected to the reflux port at the top of the condensation reaction tower coupling device 1 via an oil phase reflux pipe 19. The bottom outlet of the condensation reaction tower coupling device 1 is sequentially connected to a reaction tower bottom pump 5, an oil-alkali separation cooler 7, and an oil-alkali separator 6 via pipelines. A reboiler 4 is connected between the lower reflux port of the condensation reaction tower coupling device 1 and the outlet of the reaction tower bottom pump 5 via a pipeline. One outlet of the oil-alkali separator 6 is connected to an alkali pipe 15, and the other outlet is connected to a product reflux pipe 16 and a product outlet pipe 21, respectively. The product reflux pipe 16 connects this outlet to the liquid inlet of the extraction separator 8. The steam ejector 10 is also connected to a steam pipe 17, which is used to provide power to the steam ejector 10 to create a vacuum.

[0018] In the above-mentioned reaction apparatus, preferably, the condensation reaction tower coupling device 1 is divided into an upper distillation section and a lower reaction section. Both the distillation section and the reaction section can be cylindrical. The radius of the distillation section of the condensation reaction tower coupling device 1 is smaller than the radius of its reaction section. The distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device 1, the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights. The distillation section contains several whole tower plates 3, each of which is loaded with packing, such as Sulzer Mellapak 350Y structured 304 stainless steel packing. The reaction section contains a built-in agitator 2, such as a mechanical agitator. In addition, the reaction section is equipped with an inlet connected to the aldehyde-base feed pipe 11, an inlet and outlet connected to the reboiler 4, and a outlet connected to the bottom pump 5 of the reaction tower. The distillation section is equipped with an oil phase reflux pipe interface and a negative pressure pipe interface.

[0019] The condensation reaction tower coupling device 1 consists of a condensation circulation tower and a condensation reactor coupled together. The condensation reactor has a typical reactor structure, with a cylindrical body and arc-shaped end caps at both ends. The cylindrical wall is equipped with manholes, material flow holes, and instrumentation ports. The condensation circulation tower has a typical distillation tower structure, also with a cylindrical body and arc-shaped end caps at both ends. The column includes manholes, material inlet and outlet ports, packing, and other auxiliary instrumentation equipment. The condensation circulation tower, with its lower end cap removed, serves as the distillation section, and the condensation reactor, with its upper end cap removed, serves as the reaction section. The two circular sections are connected. All auxiliary openings, pipelines, and fittings are evenly distributed according to their center of gravity.

[0020] In the above-mentioned reaction apparatus, preferably, the air inlet of the extraction separator 8 is connected to the outlet of the extraction separator condenser 9 through a negative pressure pipe 18, the liquid inlet of the extraction separator 8 is connected to the outlet of the oil-alkali separator 6 through a product reflux pipe 16, the oil phase outlet of the extraction separator 8 is connected to the reflux port of the upper distillation section of the condensation reaction tower coupling device 1 through an oil phase reflux pipe 19, and the aqueous phase outlet of the extraction separator 8 is connected to an aqueous phase collection pipe 20.

[0021] In the above-mentioned reaction apparatus, preferably, the inlet of the bottom pump 5 of the reaction tower is connected to the outlet at the bottom of the condensation reaction tower coupling device 1 through the aldehyde-alkali discharge pipe 12. The outlet of the bottom pump 5 of the reaction tower is divided into two paths: one path is connected to the reflux port of the lower reaction section of the condensation reaction tower coupling device 1 through the reboiler reflux pipe 13, and the reboiler 4 is provided on the reboiler reflux pipe 13; the other path is connected to the inlet of the oil-alkali separator 6 through the aldehyde-alkali separation pipe 14, and the oil-alkali separation cooler 7 is provided on the aldehyde-alkali separation pipe 14.

[0022] The working principle of this novel reaction device for liquid base-catalyzed aldehyde condensation:

[0023] The raw material aldehyde and liquid alkaline catalyst (such as aqueous solutions of sodium carbonate, sodium bicarbonate, sodium acetate, sodium hydroxide, calcium hydroxide, sodium hydride, sodium alkoxide, etc.) are mixed and then fed into the condensation reaction coupling device 1 through the aldehyde-alkali feed pipe 11. Heating occurs through a loop formed by the aldehyde-alkali discharge pipe 12, the bottom pump 5 of the reaction tower, the reboiler reflux pipe 13, and the reboiler 4, and the aldehyde condensation reaction takes place under the action of the stirring paddle 2. As a violently exothermic reaction, the aldehyde condensation reaction releases heat to maintain its own reaction temperature while saving the medium-pressure steam consumed by the reboiler 4. The bottom temperature of the condensation reaction coupling device 1 is essentially equal to the reaction temperature, between 100℃ and 140℃. Simultaneously, a steam ejector 10 provides negative pressure to the condensation reaction coupling device 1, with the negative pressure between 0.001-0.005 MPa, appropriately distilling off the water generated in the aldehyde condensation reaction, maintaining the concentration of the liquid alkaline catalyst, and keeping the top temperature of the tower between 40-80℃.

[0024] The gaseous component generated by the aldehyde condensation reaction, which consists of water and a small amount of raw material aldehyde, is distilled off under the negative pressure provided by the steam ejector 10 and the heating at the bottom of the tower. After passing through the negative pressure pipe 18, it is condensed by the extraction separation condenser 9 and enters the extraction separator 8.

[0025] The product from the aldehyde condensation reaction and the liquid alkaline catalyst mixture are propelled by the bottom pump 5 of the reaction tower. After passing through the aldehyde-alkali discharge pipe 12, a portion of the mixture is returned to the condensation reaction tower coupling device 1 after being heated by the reboiler 4 via the reboiler reflux pipe 13. The other portion passes through the aldehyde-alkali separation pipe 14 and the oil-alkali separator 7 before entering the oil-alkali separator 6. The oil-alkali separator 6 separates the aldehyde condensation product from the liquid alkaline catalyst through a static overflow. The liquid alkaline catalyst is then discharged through the alkali pipe 15 for further processing. A small portion of the aldehyde condensation product is introduced into the extraction separator 8 via the product reflux pipe 16, while the other portion is directly discharged via the product discharge pipe 21.

[0026] Inside the extraction separator 8, the water condensed from the extraction separator condenser 9 and the aldehyde condensation product, two immiscible media, are used to extract the evaporated aldehyde by utilizing their different solubilities. The extracted oil phase (containing both the aldehyde condensation product and the aldehyde) is returned to the distillation section of the condensation reaction tower coupling device 1 via the oil phase reflux pipe 19, while the extracted aqueous phase is discharged through the aqueous phase collection pipe 20 for further processing.

[0027] Although the functions and working processes of this utility model have been described above in conjunction with the accompanying drawings, this utility model is not limited to the specific functions and working processes described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this utility model without departing from the spirit and scope of the claims, and all of these are within the protection scope of this utility model.

Claims

1. A reaction apparatus for liquid base-catalyzed aldehyde condensation, characterized in that, The system includes a condensation reaction tower coupling device (1) with an aldehyde-base feed pipe (11) connected to its lower part. The steam outlet at the top of the condensation reaction tower coupling device (1) is connected in sequence to a steam ejector (10), an extraction separation condenser (9), and an extraction separator (8) via a negative pressure pipe (18). The oil phase outlet of the extraction separator (8) is connected to the upper reflux port of the condensation reaction tower coupling device (1) via an oil phase reflux pipe (19). The bottom outlet of the condensation reaction tower coupling device (1) is connected in sequence via pipelines. The reaction tower bottom pump (5), oil-alkali separation cooler (7), and oil-alkali separator (6) are connected. The reboiler (4) is connected between the lower reflux port of the condensation reaction tower coupling device (1) and the outlet of the reaction tower bottom pump (5) through a pipeline. One outlet of the oil-alkali separator (6) is connected to an alkali pipe (15), and the other outlet is connected to a product reflux pipe (16) and a product outlet pipe (21), respectively. The product reflux pipe (16) is connected to the inlet of the extraction separator (8).

2. The reaction apparatus for liquid base-catalyzed aldehyde condensation according to claim 1, characterized in that, The condensation reaction tower coupling device (1) is divided into an upper distillation section and a lower reaction section. The distillation section is filled with several whole tower plates (3), each tower plate (3) is filled with packing material, and the reaction section is filled with a stirring paddle (2).

3. The reaction apparatus for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The radius of the distillation section of the condensation reaction tower coupling device (1) is smaller than the radius of its reaction section. The distillation section and the reaction section are directly connected. In the cross-section of the condensation reaction tower coupling device (1), the column heights of the reaction section and the distillation section are parallel, and the line connecting the column heights forms an obtuse angle with the column heights.

4. The reaction apparatus for liquid base-catalyzed aldehyde condensation according to claim 2, characterized in that, The condensation reaction tower coupling device (1) is formed by coupling a condensation circulation tower and a condensation reactor. The condensation circulation tower is used as a distillation section after removing the lower end cap, and the condensation reactor is used as a reaction section after removing the upper end cap.

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