Reactor Catalyst Inlet Segmentation for Uniform Mixing
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Solution Overview
Problem
In fluid catalytic reactions, such as paraffin dehydrogenation, disparities in catalyst temperature and density lead to hot spots, promoting unselective thermal cracking reactions over desired catalytic reactions, which reduces product selectivity.
Innovation Solution
A reactor design with two spent catalyst inlets and at least one regenerated catalyst inlet, arranged to ensure thorough mixing and uniform temperature and density profiles, minimizing temperature and density variations within the reaction chamber.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If regenerated catalyst at high temperature is used to increase reaction heat, then reaction conversion is improved, but thermal cracking reactions are promoted which reduces product selectivity
Solution Approach 1:
The catalyst inlet system is segmented into multiple separate inlets (first regenerated catalyst inlet, second regenerated catalyst inlet, first spent catalyst inlet, second spent catalyst inlet) positioned at different locations and angles within the reaction chamber. This segmentation allows different catalyst streams to be introduced separately and mix progressively, preventing localized high-temperature zones that cause thermal cracking while maintaining overall high conversion through sufficient reaction heat supply.
2Temperature
If catalyst circulation is increased to provide additional heat, then reaction temperature is improved, but temperature disparities increase leading to hot spots
Solution Approach 1:
Different regions of the reaction chamber are provided with different inlet configurations optimized for their local requirements. The inlets are positioned at specific angles (e.g., 45-135 degrees between spent catalyst inlets, 45-135 degrees between regenerated catalyst inlets) and locations to create localized mixing zones that progressively homogenize temperature and density throughout the catalyst bed, preventing hot spots while maintaining overall temperature stability.
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 design enhances catalyst mixing, leading to increased conversion and selectivity of catalytic reactions over thermal cracking, thereby improving overall process efficiency and product yield.
Implementation Method 1
The first spent catalyst stream, the second spent catalyst stream, the first regenerated catalyst stream, and perhaps the second regenerated catalyst stream are mixed in the reaction chamber
Data Source
AI summary
A process and reactor for contacting a feed stream with a catalyst stream comprises a reaction chamber comprising two spent catalyst inlets for delivering two spent catalyst streams to the reaction chamber and at least one regenerated catalyst inlet for delivering a regenerated catalyst stream to the reaction chamber. The reaction chamber may also include a second regenerated catalyst inlet for delivering a second regenerated catalyst stream to the reaction chamber. The second spent catalyst inlet enables thorough mixing of catalyst streams.