Catalyst Flow Regulator for FCC Mixing Device
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Solution Overview
Problem
The internal feed supply section in downflow moving-bed reactors for fluidized catalytic cracking apparatuses is complex, making maintenance difficult and leading to inefficient mixing of catalyst and feed, resulting in prolonged contact times and decreased cracking rates.
Innovation Solution
A mixing device with a catalyst flow regulator at the center of the reaction container, featuring a hollow tubular shape and refractory materials, which prevents fuel from flowing backward and ensures uniform mixing by controlling the flow of catalyst and feed injection angles, thereby maintaining efficient contact times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an internal feed supply section is provided in the downflow moving-bed reactor, then mixing efficiency is improved, but device complexity increases and maintenance difficulty increases
Solution Approach 1:
The invention extracts the feed supply function from the internal structure and relocates it to the external periphery of the reaction container. The feed supply unit is now positioned outside the reaction container with feed injection nozzles that inject feed into the peripheral region of the catalyst moving bed, eliminating the complex internal feed supply section while maintaining mixing efficiency.
Solution Approach 2:
The invention introduces a peripheral region as an intermediary zone between the external feed supply unit and the catalyst moving bed. Feed is injected into this peripheral region first, then mixed with the catalyst flowing through the center, achieving efficient mixing without requiring internal feed supply structures.
2Productivity
If an internal feed supply section is provided in the downflow moving-bed reactor, then mixing efficiency is improved, but ease of repair worsens
Solution Approach 1:
The feed supply unit is extracted from the internal structure and relocated to the external periphery of the reaction container. This allows maintenance personnel to access and service the feed supply unit from outside the reaction container, eliminating the need for complex disassembly operations required by internal feed supply sections.
3Productivity
If feed is injected at high speed to improve mixing, then mixing efficiency is improved, but harmful factors increase due to backward flow
Solution Approach 1:
The invention converts the high-speed feed injection, which could cause harmful backward flow, into a beneficial mixing mechanism. Feed is injected at high speed into the peripheral region where it naturally mixes with the downward-flowing catalyst, and the catalyst flow regulator prevents backward flow by regulating catalyst movement in the peripheral region.
Solution Approach 2:
The invention replaces mechanical mixing mechanisms with a flow-based mixing system. Feed is injected at high speed and mixed with catalyst through controlled fluid dynamics in the peripheral region, eliminating the need for mechanical mixers and reducing the risk of backward flow.
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 mixing device achieves efficient mixing without an internal feed supply section, facilitating easy maintenance and improving cracking rates while reducing light gas and coke yields.
Implementation Method 1
a catalyst flow regulator (7) which is disposed at a center in the reaction container (5) to regulate a flow of the catalyst (S)
Implementation Method 2
feed injection nozzles (6a) which are arranged at regular intervals on the outer circumference of the downstream-side portion (5b) of the reaction container (5) to inject feed into the peripheral region of the catalyst moving bed
Implementation Method 3
a distribution plate (8) which is positioned on an upstream side of the catalyst flow regulator (7) to allow the catalyst (S) to fall uniformly
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A mixing device used in a fluidized catalytic cracking apparatus which mixes feed and a catalyst includes a cylindrical reaction container 5 which supplies a catalyst S in a vertical direction; a plurality of feed injection nozzles 6a arranged along an outer circumference of the reaction container 5; and a catalyst flow regulator 7 which is provided in the reaction container 5 and regulates a flow of the catalyst S in the vicinity of the feed injection nozzles 6a. The catalyst flow regulator 7 has no feed supply function and forms a catalyst moving bed having a hollow tubular shape which is coaxial with the reaction container 5 in the vicinity of the feed injection nozzles 6a. The catalyst flow regulator 7 can effectively prevent backward flow of injected fuel. Although the mixing device has a simple structure, it has a high cracking rate and maintenance of the fluidized catalytic cracking apparatus can be performed easier.