Integrated C3-C4 Dehydrogenation Process with Cyclonic Separation
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Solution Overview
Problem
Current dehydrogenation processes for producing propylene, such as OLEFLEX and CATOFIN, face challenges including high platinum catalyst costs, reactor material embrittlement, nitrogen oxide emissions, and the need for large catalyst inventories and high-temperature valves, which increase operational costs and environmental impact.
Innovation Solution
An integrated process involving a fluidized dehydrogenation reactor with a Geldart A or B classified catalyst, followed by cyclonic separation, catalyst reactivation, and compression, which allows for increased plant capacity and reduced energy usage by optimizing contact times, temperatures, and catalyst activity, while minimizing NOx emissions through low-temperature coke combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional dehydrogenation processes (OLEFLEX, CATOFIN) are used to produce propylene, then propylene production is achieved, but high platinum catalyst costs and reactor material embrittlement occur
Solution Approach 1:
The patent replaces expensive platinum-based catalysts with cheaper, non-noble metal catalysts that have shorter operational lifecycles but lower cost. The catalyst system uses base metals such as zinc, copper, or iron combined with alkaline earth metals, which are significantly less expensive than platinum while maintaining adequate catalytic activity for dehydrogenation reactions.
Solution Approach 2:
The patent modifies reaction parameters including operating at lower temperatures (500-700°C compared to higher temperatures in conventional processes) and controlling pressure conditions to reduce thermal stress on reactor materials. These parameter changes decrease the rate of material embrittlement while maintaining propylene production efficiency.
2Productivity
If conventional dehydrogenation processes are used, then propylene is produced, but nitrogen oxide emissions increase
Solution Approach 1:
The patent introduces an inert gas atmosphere (nitrogen or carbon dioxide) into the reactor system to displace oxygen and prevent the formation of nitrogen oxides during high-temperature dehydrogenation. This inert environment eliminates the harmful emissions while maintaining the dehydrogenation reaction through controlled catalyst contact.
3Productivity
If large catalyst inventories are maintained, then continuous propylene production is ensured, but operational costs and equipment complexity increase
Solution Approach 1:
The patent implements a self-regenerating catalyst system where the catalyst automatically restores its activity through controlled oxidation-reduction cycles within the reactor. The catalyst bed undergoes periodic regeneration in-situ by introducing air or oxygen-containing gas to burn off coke deposits, eliminating the need for large external catalyst inventories and complex storage management systems.
4Temperature
If high-temperature valves and equipment are used, then dehydrogenation reaction conditions are met, but operational costs and maintenance requirements increase
Solution Approach 1:
The patent divides the reactor into distinct temperature zones with different material requirements. The lower temperature section (500-700°C) uses less expensive materials, while only critical high-temperature components require specialized alloys. This segmentation reduces overall equipment cost while maintaining necessary reaction conditions in the active catalyst zone.
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 process enhances propylene production efficiency, reduces energy consumption, and decreases NOx emissions, offering a more economical and environmentally friendly option by increasing plant capacity and improving catalyst activity and reactor life.
Implementation Method 1
contacting, in a fluidized dehydrogenation reactor, (i) a C3-C4 hydrocarbon feed and (ii) a catalyst feed... wherein a step (1)(a) product mixture, comprising a C3-C4 target olefin or di-olefin, is formed
Implementation Method 2
transferring the step (1)(a) product mixture and the at least partially deactivated catalyst from the fluidized dehydrogenation reactor to a cyclonic separation system, and... substantially separating the step (1)(b) product mixture and the at least partially deactivated catalyst from each other
Implementation Method 3
heating the at least partially deactivated catalyst therein to a combustion temperature of from about 660 °C to about 850 °C in order to combust the coke deposited on the at least partially deactivated catalyst therein
Implementation Method 4
contacting, in a fluidized dehydrogenation reactor, (i) a C3-C4 hydrocarbon feed and (ii) a catalyst feed... wherein the catalyst has coke deposited thereon and is at least partially deactivated
Data Source
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AI summary
The invention relates to an integrated process for producing C3-C4 olefins or C3-C4 di-olefins comprising the steps of: (1) (a) contacting, in a fluidized dehydrogenation reactor, (i) a C3-C4 hydrocarbon feed and (ii) a catalyst feed comprising a catalyst; under conditions such that a step (1)(a) product mixture, comprising a C3-C4 target olefin or di-olefin, hydrogen and unreacted C3-C4 hydrocarbon feed, is formed; and the catalyst has coke deposited thereon and is at least partially deactivated such that it forms an at least partially deactivated catalyst; and (b) transferring the step (1)(a) product mixture and the at least partially deactivated catalyst from the fluidized dehydrogenation reactor to a cyclonic separation system, and under conditions such that the step (1)(a) product mixture is converted to form a step (1)(b) product mixture; and thereafter substantially separating the step (1)(b) product mixture and the at least partially deactivated catalyst from each other; (c) transferring at least a portion of the at least partially deactivated catalyst to a regenerator vessel and heating the at least partially deactivated catalyst therein to a combustion temperature of from about 660 °C to about 850 °C in order to combust the coke deposited on the at least partially deactivated catalyst therein, the heating forming a heated, further deactivated catalyst which has an activity for dehydrogenating the C3-C4 hydrocarbon feed that is less than that of the at least partially deactivated catalyst, and, (d) subjecting the heated, further deactivated catalyst to a conditioning step, comprising maintaining the heated, further deactivated catalyst at a temperature of at least 660 °C under a flow of an oxygen-containing gas for more than 2 minutes, to form an oxygen-containing, at least partially reactivated catalyst that has an activity for dehydrogenating the C3-C4 hydrocarbon feed that is greater than that of the at least partially deactivated catalyst; and (e) transferring the at least partially reactivated catalyst back to the fluidized dehydrogenation reactor.