Aldehyde Vapor Fractionator Ligand Separation
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Solution Overview
Problem
Current processes for separating catalyst ligand from vaporized aldehyde streams in hydroformylation processes face challenges in efficiently removing ligands and heavy by-products, leading to ligand carryover and accumulation of unwanted by-products, which can poison downstream catalysts and result in aldehyde loss and contamination.
Innovation Solution
A process involving a fractionator to separate catalyst ligand and heavy by-products from the vapor stream, using liquid aldehyde reflux to enhance separation efficiency and a separation system to recover aldehyde, thereby preventing ligand carryover and by-product accumulation, while allowing flexible operation conditions to minimize aldehyde loss and heavy by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a dispersed liquid is sprayed into the vaporized aldehyde stream to condense vaporized ligand, then ligand carryover is reduced, but heavy by-products are also condensed and accumulate in the process
Solution Approach 1:
The process segments the condensation function into two separate systems: a fractionator that condenses and removes heavy by-products through a liquid bottom stream, and a separate condensation system that removes ligand. This segmentation allows each system to target specific contaminants without the trade-off present in single-system approaches.
Solution Approach 2:
The invention extracts the heavy by-product removal function into a separate fractionator unit that operates independently from the ligand condensation process. The fractionator takes out heavy by-products through a liquid bottom stream, preventing their accumulation while allowing the ligand condensation system to operate without having to filter through heavy by-products.
2Object-affected harmful factors
If careful control of dispersed liquid is used to promote ligand condensation while avoiding heavy by-product condensation, then ligand carryover is reduced, but the process becomes difficult to control and prone to variations
Solution Approach 1:
By segmenting the separation process into distinct fractionator and condensation units with separate control systems, the invention eliminates the need for careful balancing of a single dispersed liquid flow rate. Each unit can be controlled independently based on its specific function, greatly simplifying operation.
3Object-generated harmful factors
If the vaporiser is run at higher temperature to prevent heavy by-product accumulation, then by-product removal is improved, but ligand carryover increases
Solution Approach 1:
The invention segments the temperature control function: the vaporiser operates at higher temperature to prevent heavy by-product accumulation, while the separate fractionator and condensation systems handle ligand removal. This segmentation allows each unit to operate at optimal temperatures for its specific function without the trade-off.
4Object-affected harmful factors
If a partial condenser is used to condense phosphorous ligand and by-products, then ligand removal is achieved, but only a single theoretical stage is provided limiting separation efficiency
Solution Approach 1:
The invention replaces the single-stage partial condenser with a segmented system comprising a fractionator with multiple theoretical stages for heavy by-product separation, followed by a condensation system for ligand removal. This multi-stage segmented approach achieves both high separation efficiency and effective ligand removal.
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 effectively reduces ligand carryover and by-product accumulation, maintaining high aldehyde recovery and preventing contamination, while allowing for flexible and economical operation by creating separate streams for efficient separation and recycling, thus enhancing the overall process efficiency and reducing operational costs.
Implementation Method 1
condensing a first portion of the scrubbed vapour stream to create the liquid aldehyde, for reflux back to the fractionator
Implementation Method 2
passing the vapour stream to a fractionator in which the vapour stream is contacted with liquid aldehyde which removes at least a portion of the catalyst ligand and at least a portion of the heavy by-products from the vapour stream
Implementation Method 3
The aldehyde is separated from the catalyst by vaporisation, with the vaporised aldehyde leaving in the vapour phase and the catalyst liquor remaining as a liquid
Implementation Method 4
The present invention may be of particular utility when the ligand has a vapour pressure of at least 0.01 mbar at 160° C.
Data Source
AI summary
A process for separating heavy by-products and catalyst ligand from a vapour stream comprising aldehyde, the heavy by-products and the catalyst ligand the process comprises passing the vapour stream to a fractionator in which the vapour stream is contacted with liquid aldehyde which removes at least a portion of the catalyst ligand and at least a portion of the heavy by-products from the vapour stream, recovering a liquid bottom stream, comprising removed catalyst ligand from the fractionator; recovering a scrubbed vapour stream from the fractionator, condensing a first portion of the scrubbed vapour stream to create the liquid aldehyde, and recovering a second portion of the scrubbed vapour stream as a product aldehyde stream. The liquid bottom stream is passed to a separation system to separate some aldehyde from the liquid bottom stream to create a recovered aldehyde stream, comprising the separated aldehyde.