FCC Riser Gas Distributor for Uniform Catalyst Mixing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for distributing fluidizing gas in fluid catalytic cracking (FCC) reactors are inefficient, particularly in evenly distributing gas to facilitate mixing of separate catalyst streams, leading to potential hot spots and reduced product selectivity.
Innovation Solution
A distributor system that feeds a first stream of fluidizing gas into a chamber and a second stream outside the chamber within the riser, using a plenum with multiple nozzles to ensure even distribution and mixing of catalyst streams, enhancing the fluidization and mixing of catalysts and hydrocarbon feeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional steam ring distributor is used to distribute fluidizing gas, then the gas distribution structure is simple, but the equipment in the riser becomes cumbersome and gas distribution uniformity deteriorates
Solution Approach 1:
The distributor is segmented into multiple functional components: a main distributor body with multiple outlet ports arranged in different patterns (radial, tangential, axial), allowing different sections to serve different purposes. This segmentation enables uniform gas distribution while maintaining structural simplicity by dividing the distribution function across multiple optimized outlet regions.
Solution Approach 2:
Different outlet ports are designed with different local characteristics - some outlets are arranged radially, others tangentially, and others axially. Each local region of the distributor has optimized outlet configuration suited for its specific position, ensuring uniform gas distribution throughout the riser while keeping the overall device structure relatively simple.
2Device complexity
If open pipes or pipes with slots are used to distribute fluidizing gas, then the distributor structure is simple, but gas distribution efficiency and uniformity deteriorate
Solution Approach 1:
The distributor employs multiple outlet ports segmented into different directional groups (radial, tangential, axial outlets) rather than a single undifferentiated opening. This segmentation maintains relatively simple structure while dramatically improving gas distribution efficiency by directing gas flow optimally in different regions of the riser.
Solution Approach 2:
Each outlet port is designed with specific local characteristics appropriate to its position - radial outlets for certain regions, tangential for others, axial for others. This local optimization of outlet orientation and configuration improves overall gas distribution efficiency without requiring complex external distribution systems.
3Device complexity
If catalyst streams are not adequately mixed in the riser, then the riser structure is simple, but hot spots form and product selectivity deteriorates
Solution Approach 1:
The distributor creates preliminary turbulent mixing of catalyst streams at the bottom of the riser through strategically directed gas flow patterns before the catalyst enters the main reaction zone. This preliminary action ensures temperature uniformity is established early, preventing hot spot formation downstream while keeping the riser structure itself relatively simple.
Solution Approach 2:
The distributor uses fluid dynamics principles to generate turbulence and mixing through the arrangement and orientation of outlet ports. By controlling gas flow patterns through radial, tangential, and axial outlets, the system achieves effective catalyst stream mixing using pneumatic forces rather than mechanical mixing devices, maintaining simple riser structure.
4Device complexity
If fluidizing gas is not evenly distributed, then the distributor structure is simple, but catalyst fluidization quality and mixing deteriorate
Solution Approach 1:
The distributor is divided into multiple outlet ports with different orientations (radial, tangential, axial) to segment the gas distribution function. This segmentation ensures even gas distribution across different regions of the riser, maintaining stable catalyst fluidization while keeping the overall distributor structure relatively simple through modular outlet design.
Solution Approach 2:
Different regions of the distributor have locally optimized outlet configurations - radial outlets in some areas, tangential in others, axial in others. This local quality approach ensures uniform gas distribution throughout the riser cross-section, maintaining consistent catalyst fluidization quality without requiring a overly complex distributed outlet system.
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 approach improves the uniformity of catalyst temperature and mixing, reducing the likelihood of hot spots and enhancing the selectivity of hydrocarbon cracking products by ensuring efficient distribution of fluidizing gas across the riser.
Implementation Method 1
Inert fluidizing gas such as steam is distributed into the riser to fluidize the catalyst and to atomize the hydrocarbon feed. Fluidization of the catalyst pushes the catalyst up the riser
Implementation Method 2
A first stream of fluidizing gas is distributed from the plenum into a chamber in a riser and a second stream of fluidizing gas is distributed from the plenum into the riser outside of the chamber
Data Source
AI summary
A process and apparatus described is for distributing fluidizing gas to a riser. Fluidizing gas is delivered to a plenum below the riser. A first stream of fluidizing gas is distributed from the plenum into a chamber in a riser and a second stream of fluidizing gas is distributed from the plenum into the riser outside of the chamber. First nozzles in the plenum have a first outlet in the chamber and second nozzles in the plenum have a second outlet outside of the chamber. Streams of regenerated catalyst and carbonized catalyst may be passed to the riser and mixed around the chamber in a lower section of a riser.