Fixed-Bed Reactor Purging for Propylene Oxide Catalyst Cleanup
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Solution Overview
Problem
Existing methods face challenges in efficiently removing organic substances from a catalyst when propylene oxide production is stopped, leading to incomplete removal and prolonged downtime due to residual organic substances on the catalyst.
Innovation Solution
A method involving the use of a liquified gas and an inert gas to purge the reactor, followed by depressurization, effectively removing residual organic substances from the catalyst bed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an inert gas is supplied to the reactor after stopping production, then the reactor can be prepared for opening, but the organic substance cannot be completely removed and remains on the catalyst
Solution Approach 1:
The patent changes the physical state parameter of the purging gas from gaseous (inert gas) to liquid state (liquified gas). This phase change enables the liquid to effectively dissolve and remove organic substances from the catalyst bed, resolving the incomplete removal problem while maintaining operational ease
Solution Approach 2:
The patent utilizes phase transition by supplying a liquified gas (liquid state) that evaporates and mixes with the organic substances, then transitions back to gas phase during depressurization. This phase transition mechanism enhances the removal efficiency of organic substances from the catalyst compared to using only gaseous inert gas
2Ease of operation
If an inert gas is supplied to the reactor after stopping production, then the reactor can be prepared for opening, but a long time is required for sufficiently removing the organic substance
Solution Approach 1:
The patent changes the physical state parameter of the purging gas from gaseous to liquid state. The liquid state provides better contact and dissolution properties with organic substances, significantly accelerating the removal process and reducing the time required compared to gaseous inert gas
Solution Approach 2:
The patent employs hydraulic principles by supplying a liquified gas (liquid phase) that flows through the catalyst bed, utilizing liquid flow dynamics to efficiently displace and remove organic substances. This hydraulic approach is more effective than pneumatic (gaseous) flow for removing viscous organic residues
3Reliability
If the reactor is opened to change the catalyst when activity is reduced, then catalyst efficiency can be restored, but product and organic substances must be removed first
Solution Approach 1:
The patent changes the physical state parameter to liquid for the purging medium, which simplifies the overall process by combining dissolution and purging functions in a single step. This eliminates the need for multiple separate purging operations, reducing process complexity while ensuring complete removal of organic substances to restore catalyst efficiency
Solution Approach 2:
The patent performs preliminary action by supplying the liquified gas to pre-dissolve and remove organic substances from the catalyst bed before opening the reactor. This preliminary purification step ensures the catalyst can be safely handled and replaced without contamination, maintaining reliability while streamlining the overall process
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 method ensures efficient removal of organic substances, reducing reactor downtime and maintaining catalyst efficiency.
Implementation Method 1
supplying a liquified gas to a fixed bed reactor, allowing the liquified gas to contact a catalyst in the fixed bed reactor, thereby removing an organic substance from the catalyst
Implementation Method 2
supplying a liquified gas to a fixed bed reactor, allowing the liquified gas to contact a catalyst in the fixed bed reactor, thereby removing an organic substance from the catalyst
Implementation Method 3
When an inert gas is supplied to the reactor after stopping production of propylene oxide, the organic substance may not be completely removed
Implementation Method 4
When an inert gas is supplied to the reactor after stopping production of propylene oxide, the organic substance may not be completely removed
Implementation Method 5
A method involving the use of a liquified gas and an inert gas to purge the reactor, followed by depressurization, effectively removing residual organic substances from the catalyst bed
Data Source
Figure 1
AI summary
A method for producing propylene oxide, comprising: supplying a peroxide-containing liquid and propylene to a fixed bed reactor filled with a catalyst to produce propylene oxide; stopping the supplying of the peroxide-containing liquid; contacting a liquefied gas with the catalyst in the fixed bed reactor after the stopping of the supplying of the peroxide-containing liquid; and supplying an inert gas to the fixed bed reactor.