Acrolein Purification via Split-Feed Distillation
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Solution Overview
Problem
The existing distillation processes for purifying acrolein suffer from high holdup of toxic liquid acrolein, polymerization, and fouling due to the condensation of overhead vapor and subsequent reflux in distillation columns, which increases energy demand and complexity.
Innovation Solution
The process involves splitting the acrolein-containing liquid feed stream into two streams with different introduction temperatures into the distillation column, avoiding liquefaction of the overhead vapor stream and reducing reflux, thereby minimizing holdup and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If overhead vapor is condensed and returned as reflux in conventional distillation, then separation efficiency is improved, but holdup of toxic liquid acrolein increases and energy consumption increases
Solution Approach 1:
The harmful function of condensing overhead vapor and returning it as reflux is eliminated. Instead, the overhead vapor is directly absorbed in a separate absorption column, extracting the beneficial separation function while removing the harmful holdup and energy consumption associated with conventional reflux condensation.
Solution Approach 2:
An absorption medium is introduced as an intermediary substance to achieve the separation function. The absorption medium absorbs acrolein from the overhead vapor stream in the absorption column, replacing the need for condensation and reflux while maintaining effective separation.
2Manufacturing precision
If conventional distillation with reflux is used, then acrolein separation is achieved, but polymerization and fouling occur due to liquid acrolein accumulation
Solution Approach 1:
The step causing polymerization and fouling (condensation of overhead vapor to liquid reflux) is removed from the process. Acrolein remains in vapor phase and is directly absorbed, preventing the liquid accumulation that leads to polymerization and fouling problems.
Solution Approach 2:
The physical state parameter of acrolein is changed from liquid (in conventional reflux) to vapor phase during the separation process. By maintaining acrolein in vapor phase until direct absorption, the process avoids temperature and phase conditions that promote polymerization and fouling.
3Manufacturing precision
If overhead vapor is condensed and refluxed in conventional distillation, then purification is achieved, but reboiler duty and energy demand increase
Solution Approach 1:
The energy-intensive condensation and reflux cycle is extracted and removed from the process. Purification is achieved through direct vapor absorption, eliminating the need for repeated condensation and vaporization cycles that consume significant reboiler duty.
Solution Approach 2:
The useful action of acrolein separation is achieved in a single continuous absorption step rather than through multiple cycles of condensation and vaporization. This continuous direct absorption process maintains purification effectiveness while dramatically reducing energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces the accumulation of by-products, minimizes fouling, and decreases the reboiler duty by up to 16%, enhancing safety and efficiency in acrolein purification.
Implementation Method 1
a) splitting a liquid feed stream (1) comprising acrolein into at least a first liquid stream (2) and a second liquid stream (3), b) introducing the first liquid stream (2) with a temperature T1 into a distillation column (4)... d) withdrawing an overhead vapor stream (5) enriched in acrolein from the distillation column (4)
Implementation Method 2
the overhead vapor stream (5) obtained in step d) is absorbed in an absorption medium in an absorption step
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The present invention relates to a process for the purification of acrolein, comprising the steps of a) splitting a liquid feed stream (1) comprising acrolein into at least a first liquid stream (2) and a second liquid stream (3), b) introducing the first liquid stream (2) with a temperature T1 into a distillation column (4) at a point between the top and the bottom of the distillation column, c) introducing the second liquid stream (3) with a temperature T2 into the distillation column (4) at the top of the distillation column, d) withdrawing an overhead vapor stream (5) enriched in acrolein from the distillation column (4), and e), withdrawing a bottom stream (6) depleted in acrolein, wherein the temperature T2 of the second liquid stream (3) in step c) is lower than the temperature T1 of the first liquid stream (2) in step b).