Aldehyde Recovery from Hydroformylation Vent Streams
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Solution Overview
Problem
Current chemical processes for hydroformylation, such as those involving propylene, face challenges in recovering valuable aldehyde products from vent streams due to the presence of inert gases and alkanes, leading to significant product loss and high costs associated with complex and capital-intensive recovery methods.
Innovation Solution
A process involving a vapor phase vent stream from a chemical process is cooled in a cross-exchanger, separated into a crude product liquid stream and a gas phase stream, and then depressurized to create a cooled gas phase stream with an organics to hydrogen weight ratio greater than 8:1, which is used to cool the vent stream, allowing for the recovery of aldehydes in a cost-effective manner.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If complex and capital-intensive recovery methods are used to recover aldehyde products from vent streams, then product recovery efficiency is improved, but process complexity and capital costs increase
Solution Approach 1:
The patent extracts and separates the aldehyde product from the vent stream using a condenser that selectively condenses aldehydes at temperatures above -40°C, while leaving other components in the gas phase. This extraction approach recovers valuable aldehyde products without requiring complex multi-step separation processes.
Solution Approach 2:
The patent changes the temperature parameter in the condenser to achieve selective condensation. By operating the condenser at temperatures above -40°C, aldehydes are condensed and recovered while other vent stream components remain gaseous, simplifying the recovery process and reducing capital costs.
2Loss of substance
If high purity polymer grade propylene is used as feed, then propylene losses in bleed stream are minimized, but feed costs increase significantly
Solution Approach 1:
The patent changes the purity parameter of the propylene feed from high purity (99.5%) polymer grade to lower purity chemical grade (93-97%) propylene. The bleed stream is optimized to maintain reactor inert levels while the condenser recovers aldehyde products, making the use of cheaper chemical grade propylene economically viable.
Solution Approach 2:
The patent implements a feedback mechanism where the bleed stream composition and flow rate are adjusted based on reactor inert accumulation. The condenser also provides feedback by recovering aldehydes that would otherwise be lost, allowing the system to maintain performance while using lower purity feed.
3Quantity of substance
If chemical grade propylene with higher propane content is used, then feed costs decrease, but inert accumulation in reactor increases requiring larger bleed streams
Solution Approach 1:
The patent changes the composition parameter of the propylene feed to include higher propane content (chemical grade). The bleed stream flow rate is adjusted to maintain reactor inert levels, and the condenser recovers aldehydes from the vent stream, compensating for the increased inert load.
Solution Approach 2:
The patent makes the bleed stream flow rate dynamic, adjusting it based on the inert accumulation rate from chemical grade propylene feed. This dynamic adjustment maintains reactor performance while enabling the use of lower cost feedstock.
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 method enables the recovery of significant quantities of valuable aldehyde products from vent streams in a cost-effective and simple process, reducing product loss and operational expenses compared to existing methods.
Implementation Method 1
cooling the vent stream in a cross-exchanger to form a cooled stream
Implementation Method 2
lowering, in a depressurization device, the pressure of the gas phase stream to form a cooled gas phase stream
Data Source
AI summary
A method of managing the heat of a chemical reaction process.