Isobutyraldehyde dehydration and purification device

Abstract

The utility model discloses an isobutyraldehyde dehydration and purification device, which comprises a butyraldehyde isomer separation tower, and is characterized in that the device also comprises a dehydration coalescer and a water stripping tower, mixed butyraldehyde from a stabilization tower enters the dehydration coalescer, is dehydrated by a coalescence filter element in the dehydration coalescer, and then enters the water stripping tower; mixed butyraldehyde is fed into a butyraldehyde isomer separation tower from the top of the dehydration coalescer, isobutyraldehyde at the tower top is condensed by a tower top cooler and then enters a reflux tank to be layered, wastewater is extracted from a lower-layer water phase, isobutyraldehyde is extracted from an upper-layer oil phase, and part of the isobutyraldehyde flows back to the butyraldehyde isomer separation tower; and sending the aldehyde-containing wastewater at the bottom of the dehydration coalescer to a water stripping tower. When the device is used for separating n-butyraldehyde and isobutyraldehyde, moisture in n-butyraldehyde and isobutyraldehyde can be effectively removed under various working conditions, and qualified n-butyraldehyde and isobutyraldehyde can be obtained through separation.

Description

Technical Field

[0001] The utility model belongs to the technical field of butanol production technology and relates to an isobutyraldehyde dehydration and purification device. Background Art

[0002] The process commonly used in oxo-butanol (OXO) units is the second-generation propylene rhodium low-pressure carbonyl synthesis technology jointly developed by DAVY / DOW. It uses propylene and synthesis gas as raw materials, and produces mixed butyraldehyde through carbonylation reaction. The product passes through high and low pressure evaporation systems to separate the rhodium catalyst and recycle it back to the reactor. The mixed butyraldehyde then passes through a stripping tower and a stabilization tower to remove light components, and then enters a butyraldehyde isomerization tower to separate normal and isobutyraldehyde.

[0003] The mixed butyraldehyde from the stabilization tower often contains a small amount of water, and the water content is even higher during the initial startup of the plant. Traditional butyraldehyde isomerization towers typically use reflux tank static chromatography dehydration or side-line extraction to remove a small amount of water, but this suffers from low dehydration efficiency. The high water content in the separated isobutyraldehyde can easily lead to product failure. Continuous discharge of reflux tank wastewater can easily cause isobutyraldehyde carryover and loss. Especially during the initial startup of the system, due to the influence of carbonyl synthesis side reactions and system processing steps such as water washing and evaporation, the mixed butyraldehyde can easily exceed the water content standard. This, in turn, results in a large amount of isobutyraldehyde failing to meet the standard when the butyraldehyde isomerization tower is used to separate normal isobutyraldehyde. The excess isobutyraldehyde cannot be effectively recycled, resulting in material waste. If the isobutyraldehyde water cannot be effectively removed over a long period of time, the operating load of the carbonyl synthesis reactor cannot be increased in an orderly manner, and the entire system must operate at a low load, which restricts the speed of increasing the startup load and effectively guarantees the production efficiency of the plant. Summary of the Invention

[0004] The purpose of the utility model is to provide an isobutyraldehyde dehydration and purification device, which can effectively remove water from normal and isobutyraldehyde under various working conditions when separating normal and isobutyraldehyde, thereby greatly reducing the production of unqualified isobutyraldehyde products.

[0005] In order to achieve the above-mentioned purpose of the invention, the present invention adopts the following technical solutions:

[0006] An isobutyraldehyde dehydration and purification device comprises a butyraldehyde isomer separation tower, characterized in that the device also comprises a dehydration coalescer and a water stripping tower. Mixed butyraldehyde from a stabilization tower enters the dehydration coalescer, and after water is removed by a coalescing filter element inside the dehydration coalescer, the mixed butyraldehyde is sent from the dehydration coalescer to the butyraldehyde isomer separation tower. The isobutyraldehyde at the top of the tower is condensed by a tower top cooler and then enters a reflux tank for stratification. Wastewater is extracted from the lower aqueous phase, and isobutyraldehyde is extracted from the upper oil phase, and part of the isobutyraldehyde is refluxed to the butyraldehyde isomer separation tower. The aldehyde-containing wastewater at the bottom of the dehydration coalescer is sent to the water stripping tower.

[0007] Furthermore, the dehydration coalescer includes a coalescing filter element and a separation filter element. The coalescing filter element captures water in the mixed butyraldehyde, gathers it into droplets, and then settles in the separation filter element and is removed. The mixed butyraldehyde is discharged through the separation filter element.

[0008] Furthermore, normal butyraldehyde is extracted from the bottom of the butyraldehyde isomer separation tower.

[0009] Furthermore, the inlet of the dehydration coalescer is connected to a mixed butyraldehyde intermediate storage tank, so that the mixed butyraldehyde feed can be supplemented.

[0010] Beneficial Effects: The present invention effectively removes moisture from the feed, allowing the dehydrated mixed butyraldehyde to be rapidly separated within the isomerization tower. Under various operating conditions, qualified normal butyraldehyde is separated at the bottom of the tower through mass and heat transfer, while qualified isobutyraldehyde is separated at the top of the tower. The purity of the top isobutyraldehyde is no longer restricted by water content, significantly improving the yield rate and avoiding material consumption and waste of isobutyraldehyde due to water removal. This also effectively ensures system startup efficiency. During startup, the propylene load can be rapidly increased, allowing the subsequent condensation and hydrogenation units of the system to achieve rapid, high-load startup, effectively ensuring the production efficiency and economic benefits of the device. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG1 is a schematic structural diagram of an isobutyraldehyde dehydration and purification device of the present invention;

[0012] Among them, 1 is a butyraldehyde isomer separation tower, 2 is a dehydration coalescer, 3 is a top cooler, 4 is a reflux tank, 5 is a normal butyraldehyde extraction pump, 6 is a reflux pump, 7 is an intermediate storage tank feed valve, 8 is a stabilization tower feed valve, and 9 is a water stripping tower. DETAILED DESCRIPTION

[0013] The technical solutions of the present invention are further described in detail below through specific embodiments. However, it is necessary to point out that the following embodiments are only used to describe the content of the invention and do not constitute a limitation on the protection scope of the present invention.

[0014] like Figure 1 As shown, the isobutyraldehyde dehydration and purification device of the present invention includes a butyraldehyde isomer separation tower 1, a dehydration coalescer 2, a tower top cooler 3, a reflux tank 4, a normal butyraldehyde extraction pump 5, a reflux pump 6, an intermediate storage tank feed valve 7, a stabilization tower feed valve 8, a water stripping tower 9, etc.

[0015] Purification of the mixed butyraldehyde feedstock occurs primarily within butyraldehyde isomer separation tower 1. Qualified normal butyraldehyde is separated at the bottom of the tower through mass and heat transfer, while qualified isobutyraldehyde is separated at the top. The overhead vapor enters overhead cooler 3, where it condenses and enters reflux tank 4, where it is separated into two phases: oil and water. The water phase is extracted from the bottom of reflux tank 4 and treated for wastewater. The oil phase, consisting of isobutyraldehyde, is partially refluxed to butyraldehyde isomer separation tower 1 via reflux pump 6, with the remaining extracted portion being qualified isobutyraldehyde product.

[0016] The mixed butyraldehyde feed from the stabilization tower first enters dehydration coalescer 2 to remove moisture. Dehydration coalescer 2 is equipped with a coalescing filter and a separation filter. The coalescing filter uses a microporous structure to capture small droplets (water) in the mixed butyraldehyde. As the small droplets aggregate, they gradually increase in size. Because the large droplets have a greater density than the mixed butyraldehyde, they settle by gravity and are separated from the separation filter. The separated aldehyde-containing wastewater is then fed from the bottom of dehydration coalescer 2 to water stripping tower 9. The floating mixed butyraldehyde is discharged from the separation filter under pressure and fed to butyraldehyde isomer separation tower 1.

[0017] The isobutyraldehyde dehydration and purification device, the separation process of normal and isobutyraldehyde is as follows:

[0018] 1) During normal startup of the butanol and octanol unit, open the stabilizer tower feed valve 8. The mixed butyraldehyde feed from the stabilizer tower passes through the dehydration coalescer 2 and enters the butyraldehyde isomer separation tower 1 for separation of normal and isobutyraldehyde. The aldehyde-containing wastewater removed by the dehydration coalescer 2 is sent to the water stripping tower 6 for treatment and discharge after meeting standards. The normal butyraldehyde at the bottom of the butyraldehyde isomer separation tower 1 is sampled and analyzed to confirm compliance. If the product meets standards, the normal butyraldehyde can be fed to the subsequent condensation system. The isobutyraldehyde at the top of the tower passes through the cooler 3 and enters the reflux tank 4, where it is separated into oil and water phases. The water phase is withdrawn for wastewater treatment, while the oil phase is partially refluxed to the butyraldehyde isomer separation tower 1 and partially withdrawn. If the isobutyraldehyde is sampled and analyzed and meets standards, the withdrawn portion can be transferred to the product tank. If the isobutyraldehyde is unqualified, adjust the steam and reflux ratios to ensure stable mass and heat transfer. Once both normal and isobutyraldehyde meet standards, the propylene feed load of the previous system can be increased.

[0019] 2) If there is too much material stored in the intermediate tank area and it needs to be returned, or if the front system fails and the material supply is insufficient, the mixed butyraldehyde intermediate storage tank feed valve 7 from the intermediate tank area can be opened to increase the mixed butyraldehyde feed to the intermediate storage tank and perform system stabilization operations.

Claims

1. An isobutyraldehyde dehydration and purification device, comprising a butyraldehyde isomer separation tower (1), characterized in that: The device further comprises a dehydration coalescer (2) and a water stripping tower (9). The mixed butyraldehyde from the stabilization tower enters the dehydration coalescer (2), and after water is removed by a coalescing filter element inside the dehydration coalescer (2), the mixed butyraldehyde is sent from the dehydration coalescer (2) to the butyraldehyde isomer separation tower (1). The isobutyraldehyde at the top of the tower is condensed by a tower top cooler (3) and enters a reflux tank (4) for stratification. Wastewater is extracted from the lower aqueous phase, and isobutyraldehyde is extracted from the upper oil phase, and part of the isobutyraldehyde is refluxed to the butyraldehyde isomer separation tower (1). The aldehyde-containing wastewater at the bottom of the dehydration coalescer (2) is sent to the water stripping tower (9).

2. The isobutyraldehyde dehydration and purification device according to claim 1, wherein The dehydration coalescer (2) comprises a coalescing filter element and a separating filter element.

3. The isobutyraldehyde dehydration and purification device according to claim 1, wherein Normal butyraldehyde is extracted from the bottom of the butyraldehyde isomer separation tower (1).

4. The isobutyraldehyde dehydration and purification device according to claim 1, characterized in that: The inlet of the dehydration coalescer (2) is connected to the mixed butyraldehyde intermediate storage tank.

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