Quenching Column for Ethylbenzene Dehydrogenation Effluent Cooling
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Solution Overview
Problem
The existing processes for cooling the stream leaving an ethylbenzene dehydrogenation reactor face challenges in efficiently removing divinylbenzene and polymerics, which leads to fouling and plugging issues in condensers and other equipment, and do not effectively utilize the latent heat of condensation for energy recovery.
Innovation Solution
A process involving quenching the dehydrogenation effluent gas with an aqueous reflux in a quenching column, followed by condensation and separation into liquid and gaseous phases, with the aqueous phase being reused as reflux and optionally treated with an aromatic component in a mixing tank to enhance phase separation, and further processed through a stripper to remove remaining organic components, thereby preventing fouling and optimizing energy use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the dehydrogenation effluent is cooled using conventional cooling zones, then the stream is condensed, but divinylbenzene and polymerics cause fouling and plugging in condensers
Solution Approach 1:
The effluent is quenched with steam before entering the condenser, which removes divinylbenzene and polymerics in advance. This preliminary action prevents these components from reaching the condenser and causing fouling, while still achieving the required cooling effect
Solution Approach 2:
The quenching process extracts and removes the problematic divinylbenzene and polymerics components from the effluent stream before condensation. This separation prevents the fouling substances from entering the condenser system
2Productivity
If steam is used in large quantities for dehydrogenation, then the reaction is maintained, but the latent heat of condensation is not effectively utilized for energy recovery
Solution Approach 1:
The latent heat of condensation of the steam in the effluent, which would normally be wasted heat, is converted into a useful resource by using it to heat the quenching steam. This transforms the energy that would be lost into a beneficial heating effect that maintains dehydrogenation efficiency
Solution Approach 2:
The cooling condensation process and the steam generation process are merged into a single integrated system. The condensation of steam from the effluent and the generation of quenching steam occur simultaneously, allowing heat exchange between the two streams and eliminating energy loss
3Reliability
If the effluent is quenched with aqueous phase, then divinylbenzene and polymerics are removed, but additional separation and treatment steps are required
Solution Approach 1:
The quenching column performs multiple functions simultaneously: it cools the effluent, removes divinylbenzene and polymerics, generates quenching steam, and separates phases. This multi-functionality reduces the need for additional separate treatment steps despite the added quenching operation
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 process effectively removes divinylbenzene and polymerics, preventing fouling and plugging, and allows for energy savings by optimizing the use of the aqueous phase for steam generation and efficient separation of styrene and ethylbenzene, ensuring clean aqueous streams that do not induce polymerizations in equipment.
Implementation Method 1
quenching the dehydrogenation effluent gas with an aqueous reflux in a quenching column, followed by condensation
Implementation Method 2
do not effectively utilize the latent heat of condensation for energy recovery
Implementation Method 3
followed by condensation and separation into liquid and gaseous phases
Implementation Method 4
optionally treated with an aromatic component in a mixing tank to enhance phase separation
Implementation Method 5
further processed through a stripper to remove remaining organic components
Data Source
AI summary
The present invention is a process for the production of styrene monomer from ethylbenzene comprising the steps of:a) catalytically dehydrogenating said ethylbenzene in the presence of steam thereby catalytically producing a dehydrogenation effluent gas containing essentially unreacted ethylbenzene, styrene monomer, hydrogen, steam and divinylbenzene;b) quenching said effluent gas with an aqueous reflux in at least a quenching column to cool said effluent gas, and thereby obtaining a gas at the overhead and in the bottom a liquid stream warmer than the aqueous reflux;c) condensing said overhead gas thereby producing a liquid organic phase, an aqueous phase and a gaseous phase;d) using a portion or the whole of said aqueous phase of step c) as reflux for said step b) of quenching;e) sending to a decanter the liquid stream obtained at step b) to recover an aqueous phase and an organic phase.