Fractionating tower for separating acrylic aldehyde from 3-hydroxypropionaldehyde solution

A technology of hydroxypropionaldehyde and rectification tower, applied in the field of rectification tower, can solve the problems of high investment in thin-film evaporator equipment, condenser operation cost, difficulty in maintaining the operating temperature of the tower kettle, difficulty in polymerization and recovery of acrolein, etc. Effects of flux, increased thickness, increased throughput

Active Publication Date: 2007-09-12
SHANGHAI HUAYI NEW MATERIAL
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  • Abstract
  • Description
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  • Application Information

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Problems solved by technology

In U.S. Patents US3518310, US5015789, US5093537, and US6140543, it is mentioned that a thin film evaporator is used to separate the acrolein in the 3-hydroxypropanal solution, so as to shorten the contact time with the heat source as much as possible, thereby avoiding the polymerization of acrolein and the occurrence of side reactions. Although the recovery rate of acrolein has been improved, the equipment investment for the thin film evaporator and the operation cost of the condenser are relatively large, and the operation is also relatively difficult.
In the Chinese patent CN1176057, it is mentioned that adopting vacuum rectification and introducing an inert gas method in the dealdehyde process to separate and recover acrolein, although this method can effectively reduce the operating temperature of the rectifying tower and reduce the generation of by-products, but In the process of acrolein condensation recovery, it is still easy to cause the polymerization and recovery of acrolein, which leads to the reduction of the recovery rate of acrolein
In the Chinese patent CN1803750A, it is proposed to adopt the gas stripping-absorption method to strip acrolein from the reaction product by feeding gas at the bottom of the dealdehyde tower, and then absorb it with water in the absorption tower, so as to realize the separation of acrolein and recovery, although the separation effect of this method is good, and the recovery rate of acrolein is high, but the newly added absorption tower causes an increase in equipment investment, which still lacks competitiveness
In Chinese patent CN1477092, a kind of acrylic acid purification and light removal tower adopting large-pore sieve plates in the stripping section and co-current jet trays in the rectification section is proposed. The use of co-current jet trays in the rectification section can reduce the pressure and pressure of the rectification section. The operating temperature reduces the polymerization tendency of acrylic acid at the bottom of the tower, but the structure of the large-pore sieve plate is adopted in the stripping section because the concentration of acrylic acid in the stripping section is high and it is easy to polymerize, which leads to a decrease in the flux of the stripping section, which is seriously restricted The processing capacity of the whole tower, at the same time, caused a high pressure drop in the stripping section, and it was difficult to maintain the operating temperature of the bottom of the tower within a low range, which could not fundamentally solve the problem of polymerization of acrylic acid at the bottom of the tower

Method used

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  • Fractionating tower for separating acrylic aldehyde from 3-hydroxypropionaldehyde solution
  • Fractionating tower for separating acrylic aldehyde from 3-hydroxypropionaldehyde solution
  • Fractionating tower for separating acrylic aldehyde from 3-hydroxypropionaldehyde solution

Examples

Experimental program
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Effect test

Embodiment 1

[0019] The 3-hydroxy propionaldehyde aqueous solution containing 4.5% (mass) of acrolein is continuously entered into the acrolein separation tower, and the material inlet [6] in the tower is fed. The tower height is 6000 mm, and the tower diameter is 800 mm. Corrugated ceramic structured packing with a porosity of 75% [8], and 10 vertical sieve trays in the upper part of the rectification section [2], the mass transfer unit of the tray can prevent a small amount of acrolein polymer that may be produced in the rectification section from clogging the tower If a small amount of polymer is generated, it is easy to remove, and the height of the overflow weir is 10mm. During the implementation process, the pressure drop of the whole tower is 5kPa, the operating temperature at the bottom of the tower is 60°C, and the mass content of acrolein in the 3-hydroxypropionaldehyde aqueous solution of the tower bottom material after removing acrolein is 0.5%, which fully meets the requirement...

Embodiment 2

[0021]The 3-hydroxy propionaldehyde aqueous solution containing 4.5% (mass) of acrolein is continuously entered into the acrolein separation tower, and the material inlet [6] in the tower is fed. The tower height is 6000 mm, and the tower diameter is 800 mm. Corrugated ceramic structured packing with a porosity of 75%, the five vertical sieve trays [3] in the upper part [2] of the rectifying section in Example 1 are replaced with co-current injection packed trays [5], and the remaining five vertical sieve trays are [3] remain unchanged, and open holes in the upper part of the mass transfer unit to further reduce the pressure drop of the device. At the same time, in order to enhance the effect of gas-liquid mass transfer, the height of the overflow weir is increased to 15mm. During the implementation process, the mass content of acrolein in the 3-hydroxypropionaldehyde material at the bottom of the tower is controlled at 0.4%, the pressure drop of the whole tower is kept at abo...

Embodiment 3

[0023] The 3-hydroxy propionaldehyde aqueous solution containing 4.5% (mass) of acrolein is continuously entered into the acrolein separation tower, and the material inlet [6] in the tower is fed. The tower height is 6000 mm, and the tower diameter is 800 mm. For the corrugated ceramic structured packing with a porosity of 75%, the 8 new vertical sieve trays [3] in the upper part [2] of the rectification section in Example 1 are replaced with co-current injection packed trays [5], and the remaining 2 vertical sieve trays are The plate [3] remains unchanged and is perforated in the upper part of the mass transfer unit to further reduce the pressure drop of the unit. At the same time, in order to enhance the effect of gas-liquid mass transfer, the height of the overflow weir is increased to 15mm. During the implementation process, the mass content of acrolein in the 3-hydroxypropionaldehyde material at the bottom of the tower is controlled at 0.3%, the pressure drop of the whole...

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Abstract

This invention provides a rectifying tower for separating and hydrate acrolein to prepare non-reacted acrolein in a 3-lactic aldehyde reacted product, the top of the tower applies a new vertical seeve plate and the lower part applies a parallel flow jet filling tower plate and the rectifying section applies structured packing, which can increase the separation ability of towers to reduce pressure drop of the tower and operation temperature, reduce aggregation trend and reduction and aggregation trend of 3-hydroxide propaldehyde so as to reduce the loss of acrolein in the top tower.

Description

technical field [0001] The invention relates to a rectification tower for separating acrolein in 3-hydroxy propionaldehyde solution. Specifically, the present invention relates to a rectification column in which structured packing is used in the stripping section of a rectification tower, the upper part of the rectification section is a new type of vertical sieve plate, and the lower part of the rectification section is a co-current injection packing tray. Background technique [0002] Acrolein is an unsaturated compound with a double bond. Its chemical properties are very active. Its vinyl group is very easy to self-polymerize or copolymerize with other monomers. Because the polymerization reaction is fast and releases a lot of heat, once it happens, it will be very fast. It is difficult to control, so preventing the polymerization of acrolein is the first consideration when designing the acrolein separation system. Temperature is one of the factors that initiate the polym...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C47/22C07C45/78
Inventor 唐勇张春雷刘汉勇
Owner SHANGHAI HUAYI NEW MATERIAL
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