Offgas Cobalt Recovery via Absorption Liquid Recycling
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Solution Overview
Problem
The existing technologies for cobalt recovery in hydroformylation processes face challenges in efficiently removing volatile cobalt from offgases, leading to equipment fouling and operational issues due to the formation of cobalt deposits, which complicates downstream processing and increases maintenance needs.
Innovation Solution
A process is developed that involves a demetalling step to separate cobalt from the hydroformylation reaction product, followed by a gas treatment step where the volatile cobalt carbonyl is absorbed into an absorption liquid, and the cobalt-containing liquid is recycled back to the demetalling step, allowing for effective removal and recovery of cobalt without the need for high-pressure pumps or additional absorption steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If volatile cobalt is not removed from offgases, then the process is simpler, but equipment fouling and cobalt deposits form causing operational issues
Solution Approach 1:
The invention extracts volatile cobalt from the offgas stream using an absorption liquid in a scrubber system. The absorption liquid selectively absorbs cobalt carbonyl compounds from the gas phase, removing the harmful component while allowing the main process to continue uninterrupted, thus preventing equipment fouling without adding complex processing steps to the hydroformylation reaction itself
Solution Approach 2:
The invention introduces an absorption liquid as an intermediary substance that mediates between the offgas stream and the cobalt recovery system. This liquid intermediary absorbs volatile cobalt in a controlled manner, enabling efficient cobalt removal and preventing deposits on equipment surfaces without requiring direct contact between the offgas and complex separation equipment
2Loss of substance
If traditional cobalt recovery methods are used, then cobalt can be recovered, but additional absorption steps and high-pressure pumps are required increasing complexity
Solution Approach 1:
The invention combines the cobalt absorption and recycling functions into a single integrated system. The absorption liquid that captures volatile cobalt from offgases is directly recycled back to the hydroformylation reactor, merging the separation and recovery operations into one continuous loop, thereby eliminating the need for additional absorption steps and high-pressure pumping equipment
Solution Approach 2:
The absorption liquid system is designed to be self-sufficient, where the liquid that absorbs cobalt from offgases automatically recycles back to the reactor without requiring external high-pressure pumps. The system uses the existing process pressure and flow dynamics to drive the recycling, reducing mechanical complexity while maintaining effective cobalt recovery
3Object-affected harmful factors
If volatile cobalt is removed from offgases, then equipment fouling is reduced, but additional gas treatment steps are needed
Solution Approach 1:
The invention converts the harmful volatile cobalt in offgases into a beneficial recovered resource. By absorbing cobalt carbonyl compounds in the offgas stream, the system prevents equipment fouling while simultaneously recovering valuable cobalt for recycling to the reactor, transforming a waste stream into a resource recovery opportunity
Solution Approach 2:
The invention implements a discard-and-recover strategy where volatile cobalt is discarded from the offgas stream through absorption in a scrubber, and simultaneously recovered in the absorption liquid for recycling. This dual action eliminates equipment fouling while maintaining cobalt catalyst inventory, preventing loss without requiring complex multi-step treatment processes
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 simplifies the removal of volatile cobalt, reduces fouling and maintenance issues, and enhances the efficiency of cobalt recovery, thereby improving the overall hydroformylation process by allowing for a more straightforward and energy-efficient recycling of cobalt catalysts.
Implementation Method 1
the gas stream (4) is treated with an absorption liquid for absorbing at least part of the volatile cobalt carbonyl contained in the gas
Data Source
Figure 1
AI summary
In the hydroformylation of C5-C14 olefins with cobalt catalyst to produce C6-C15 oxygenates, where offgasses from the hydroformylation or cobalt removal step contain volatile cobalt compounds, the cobalt compounds are recovered by scrubbing the offgas with a liquid, and recycling the liquid to the cobalt removal step. Suitable scrubbing liquids are the organic cobalt-depleted hydroformylation reaction product or a downstream derivative thereof, or an aqueous solution of a Co2+ salt, preferably such salt of formic acid.