Cyclone Separators for FCCU Catalyst Suspension
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Solution Overview
Problem
Current separation systems in fluid catalytic cracking units (FCCUs) face challenges in efficiently separating spent catalysts and hydrocarbons under varying operational conditions, particularly with high catalyst/hydrocarbon ratios and rapid changes, leading to increased residence time, product degradation, and complex operational demands.
Innovation Solution
A new separation system integrating both inertial and centrifugal separation devices, including cyclones with and without sealing legs, is designed to operate efficiently under extreme conditions, featuring a compact configuration with cyclones arranged circumferentially around the vertical section and a fluidized bed for catalyst regeneration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional separation systems are used in FCCUs, then separation can be performed, but residence time increases leading to product degradation and excessive coke formation
Solution Approach 1:
The separation system is divided into multiple cyclone separators arranged in series, where each cyclone handles a portion of the separation task. This segmentation allows the suspension to be processed through multiple separation stages in quick succession, reducing overall residence time while maintaining high separation efficiency. The patent describes a system with multiple cyclones connected in sequence, where spent catalyst particles are progressively separated from hydrocarbon vapors across several stages.
Solution Approach 2:
The patent transitions from conventional single-stage separation to a multi-dimensional arrangement of cyclone separators. The cyclones are positioned at different heights and angular positions around the vertical section, creating a three-dimensional separation architecture. This spatial arrangement optimizes flow patterns and reduces residence time by enabling parallel processing paths while maintaining effective separation.
2Adaptability or versatility
If multiple risers operate under different conditions, then operational flexibility increases, but separation system complexity and volume increase
Solution Approach 1:
The separation system is designed as a universal configuration that can handle suspensions from multiple risers operating under different conditions. The same cyclone separator arrangement and operational parameters can process suspensions with varying catalyst-to-hydrocarbon ratios, densities, and flow rates. This multi-functional design eliminates the need for separate specialized separation systems for each riser, reducing overall complexity while maintaining adaptability.
Solution Approach 2:
The patent combines the separation outputs from multiple risers into a single integrated separation system. Instead of having separate separation units for each riser, the suspension from all risers is directed to a common set of cyclone separators. This merging approach simplifies the overall system architecture, reduces equipment volume, and maintains operational flexibility through unified control of separation parameters.
3Productivity
If high catalyst/hydrocarbon ratios are used, then conversion rates increase, but separation becomes more difficult and residence time increases
Solution Approach 1:
The patent employs multiple cyclone separators that replicate the same separation mechanism in parallel. Each cyclone is an identical copy designed to handle a specific portion of the high-catalyst suspension. This copying approach allows the system to process high catalyst-to-hydrocarbon ratios efficiently by distributing the separation load across multiple identical units, maintaining short residence time while achieving complete separation.
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 system significantly enhances the separation efficiency, reducing the residence time and catalyst flow to cyclones, achieving up to 99.8% catalyst separation with reduced erosion and instability, while maintaining product quality.
Implementation Method 1
a vertical section (6) configured to receive the suspension from the at least one ascending flow reaction tube and deflect it downwards, wherein a first inertial separation of the spent catalysts from the suspension takes place in the vertical section (6)
Implementation Method 2
The separation device comprises a plurality of cyclone separators arranged circumferentially around the vertical section (6) of the interconnection means (4), each cyclone separator being in fluid communication with the vertical section (6) and configured to separate spent catalysts from the suspension using centrifugal force
Implementation Method 3
The separation device comprises a fluidized bed (12) configured to receive spent catalysts from the cyclone separators and regenerate the catalyst particles
Data Source
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AI summary
The present invention relates to a system for the separation of suspensions of spent catalysts and hydrocarbons formed in a fluid catalytic cracking unit with at least one ascending flow reaction tube, said separation device comprising: a vertical section fluidly connected to said at least one ascending flow reaction tube such that said suspension can be transferred from said at least one ascending flow reaction tube to an inlet of said vertical section; an opening device, connected to said vertical section below said inlet, said opening device being configured to allow at least a portion of said spent catalyst to drain there through; a first cyclone separator configured to receive and separate at least a part of the suspension that has not drained from said vertical section through said opening device; and a second cyclone separator configured to receive and separate at least a part of the suspension from said first cyclone separator. The present invention also relates to a process for the separation of suspensions of spent catalysts and hydrocarbons using the said separation system.