Acrolein Separation Using Disposable Organic Solvent
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Solution Overview
Problem
Current processes for separating acrolein from propene oxidation products are inefficient, leading to frequent system cleaning, energy consumption, and contamination due to polymer formation, with complex solvent recovery and additional impurities.
Innovation Solution
A continuous process involving gas phase oxidation of propene with a heterogeneous catalyst, using a barely water-soluble organic solvent for separation and recycling, which reduces foam formation and increases system throughput while simplifying solvent processing and recycling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If water/solvent mixtures are used as washing solution for acrolein separation, then polymer deposition in apparatus and pipes is reduced, but additional effort for cleaning and recycling the solvent is required
Solution Approach 1:
The patent uses a water-soluble organic solvent (alcohol) that can be easily disposed of and replaced rather than complex recycling. The solvent is introduced in the quenching stage and eventually disposed of in the distillation stage, eliminating the need for complex recycling systems while maintaining system availability
Solution Approach 2:
The patent changes the chemical parameters of the washing solution by using a water-soluble organic solvent (alcohol) instead of conventional water-only systems. This parameter change allows the solvent to effectively reduce polymer deposition while being easily manageable through simple introduction and disposal operations
2Manufacturing precision
If large amounts of solvent are used and circulated for extractive separation, then acylic acid separation is improved, but energy consumption and additional impurities from solvent reaction increase
Solution Approach 1:
Instead of circulating large amounts of solvent that require energy-intensive recovery, the patent introduces a water-soluble organic solvent in the quenching stage and disposes of it in the distillation stage. This approach achieves effective separation without the need for complex, energy-consuming solvent recovery systems
Solution Approach 2:
The patent extracts the organic solvent from the system after it has served its purpose in reducing polymer deposition and aiding separation. The solvent is taken out in the distillation stage along with water, eliminating the need for complex recycling while maintaining separation efficiency
3Reliability
If stabilizer is added to prevent polymerization, then polymer formation is reduced, but small amounts of oligomers still accumulate in sorption liquid over time
Solution Approach 1:
The patent introduces a water-soluble organic solvent (alcohol) as an intermediary substance in the quenching stage that actively prevents polymerization by interfering with the polymerization mechanism. This intermediary provides continuous protection throughout the process, extending operating time between cleanings
Solution Approach 2:
The patent changes the chemical environment in the quenching stage by adding a water-soluble organic solvent, which fundamentally alters the polymerization kinetics. This parameter change provides sustained polymerization control that extends the operating cycle before cleaning is required
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
The process extends operating time, reduces energy consumption, and minimizes solvent usage, enabling efficient and cost-effective separation and recycling of acrolein with reduced polymer formation and improved system availability.
Implementation Method 1
The oxidation of the propene takes place on catalysts placed in tube bundle reactors at elevated temperatures (300 - 400 °C) and slightly increased pressure
Implementation Method 2
Gas phase oxidation of propene with the aid of air on a heterogeneous catalyst in the presence of a diluent gas in a reaction stage to produce a gas stream containing acrolein
Implementation Method 3
collecting the acrolein-containing gas stream from A) in a quench stage consisting of bottom, medium - and head part for separating by-products in the presence of water and an organic phase containing barely water-soluble organic solvent
Implementation Method 4
separating the acrolein from the by distillation organic phase-containing aqueous acrolein solution from C) in a distillation stage
Implementation Method 5
separating the acrolein from the by distillation organic phase-containing aqueous acrolein solution from C) in a distillation stage
Implementation Method 6
the remaining aqueous solution containing organic phase, freed from acrolein, is discharged from the distillation stage D), so that an organic phase II is formed, which is separated from the associated aqueous portion II (phase separation II)
Data Source
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AI summary
The invention relates to a method for removing acrolein from the process gas of a heterogeneously catalysed oxidation of propene by means of atmospheric oxygen, wherein, first, high boilers (including acrylic acid) are removed from the process gas by means of quenching and then industrial acrolein having small low-boiler fractions is obtained by means of absorption and subsequent distillation. A solvent is added in small amounts in the columns and heat exchangers in the reprocessing process, by means of which solvent formed oligomers in particular are removed and a foam-formation tendency is reduced in the apparatuses and columns. According to the invention, the solvent is removed in situ within the existing method in the form of an organic phase and recycled.