Side-Orifice Feed Distributor for Uniform FCC Riser Mixing
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Solution Overview
Problem
Distributing hydrocarbon feed evenly across the cross-section of a riser reactor in Fluid Catalytic Cracking (FCC) units, particularly in larger diameters, is challenging due to limitations in feed distribution to the center and near the wall, affecting mixing efficiency and conversion rates.
Innovation Solution
A feed distributor with a cluster of orifices positioned on the side and end of the distributor, allowing for even distribution of hydrocarbon feed across a greater cross-section by using multiple clusters at different positions, reducing droplet size requirements and enhancing mixing uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feed distributors spray dispersion steam and hydrocarbon feed into the riser with horizontal component across the riser, then feed can be distributed to some areas of the cross-section, but feed distribution to particular areas between the feed distributors is difficult to achieve
Solution Approach 1:
The feed distributor is divided into multiple injection zones along its length, with each zone containing orifices that spray feed into different radial and axial regions of the riser. This segmentation allows comprehensive coverage of the entire cross-section, including areas between traditional distributor locations.
Solution Approach 2:
The invention transitions from conventional single-point or end-only injection to multi-dimensional injection by positioning orifices at various locations along the distributor length and orienting them at different angles. This creates a three-dimensional spray pattern that distributes feed uniformly across the entire riser cross-section.
2Quantity of substance
If feed injection is directed toward the center of the riser with limited spray angle, then feed can be concentrated in the core area, but distributing feed to catalyst flowing close to the wall is inhibited
Solution Approach 1:
Different sections of the feed distributor have orifices with different spray angles and orientations tailored to their specific location. Orifices near the center spray at angles that penetrate the core, while orifices at other positions spray toward the walls, ensuring each region receives appropriate feed distribution.
Solution Approach 2:
The spray pattern is extended from a single-direction center-focused injection to multi-directional injection by orienting orifices at various angles relative to the distributor axis. This creates radial and axial spray components that collectively cover the entire riser cross-section uniformly.
3Volume of stationary object
If larger riser diameters are used, then reactor capacity is increased, but difficulty in distributing feedstock to the center of the riser is exacerbated
Solution Approach 1:
The feed distributor is designed as an extended structure with multiple injection zones spaced along its length to match the larger riser diameter. Each zone contains orifices that spray feed into specific radial regions, ensuring comprehensive coverage of the expanded cross-section including the center and peripheral areas.
Solution Approach 2:
The invention uses multi-dimensional spray patterns with orifices oriented at various angles to achieve radial and axial distribution of feed across the larger riser cross-section. This creates a three-dimensional feed distribution pattern that effectively covers the expanded reactor capacity while maintaining uniformity.
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
Achieves uniform distribution of hydrocarbon feed across the riser cross-section, improving mixing with catalyst and enhancing conversion efficiency, especially in larger FCC units.
Implementation Method 1
Hydrocarbon feed distributors spray dispersion steam and hydrocarbon feed into the riser at a tip exit velocity with a horizontal component across the riser
Implementation Method 2
An inert lift gas such as steam may be used to accelerate catalyst in a lower section of the riser below or during introduction of the feed
Implementation Method 3
Catalyst and hydrocarbon feed are transported upwardly in the riser by the expansion of the gases that result from the vaporization of the hydrocarbons
Data Source
AI summary
An apparatus comprising a feed distributor comprising a side cluster of orifices instead of or in combination with an end cluster of orifices for distributing hydrocarbon feed into a catalyst stream. A side cluster of orifices in conjunction with an end cluster of orifices on a feed distributor can distribute hydrocarbon feed into a riser over a greater cross-sectional extent enabling emission of smaller droplet sizes which provide better conversion with less coke production.