Fluidized Bed Reactor Circulation Using Splashgenerator and Gaswall
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Solution Overview
Problem
Existing fluidized bed reactors face challenges in combining the advantages of circulating fluidized bed (CFB) and bubbling fluidized bed (BFB) designs, particularly in managing particle circulation and reaction zones, which leads to high operational costs, erosion, and inefficient heat transfer.
Innovation Solution
A fluidized bed reactor is configured with a splashgenerator to impart directed momentum to bed solids, creating a low-density splashzone for controlled circulation between reaction zones, separated by a bedwall and gaswall, allowing independent gas and solid phase control, thereby integrating CFB and BFB features in a compact design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If CFB designs are used to provide circulation between reactors, then circulation capability is improved, but particle erosion and damage to reactor walls increases
Solution Approach 1:
The reactor is divided into multiple zones separated by internal walls (bedwall, gaswall) that segment the particle circulation paths. This allows circulation to occur in controlled segments rather than throughout the entire reactor, reducing erosion while maintaining circulation capability
Solution Approach 2:
Internal walls act as intermediaries that guide and control particle flow between zones. The bedwall and gaswall serve as mediating structures that enable circulation while protecting reactor surfaces from direct particle impact
2Adaptability or versatility
If BFB particles are circulated in prior CFB designs, then circulation is achieved, but very high gas velocities are required which are expensive to generate
Solution Approach 1:
The circulation path is segmented into controlled zones with internal walls, allowing BFB particles to circulate at lower velocities than would be required in a conventional CFB design. The segmentation creates favorable flow paths that reduce energy requirements
Solution Approach 2:
The invention changes the operational parameters by allowing BFB particles (typically operated at low velocity) to circulate within a modified reactor configuration. This parameter change enables circulation without requiring the high gas velocities characteristic of traditional CFB systems
3Quantity of substance
If CFB particles are used in a BFB, then smaller particle sizes are utilized, but very large beds are required to achieve desired reaction rates
Solution Approach 1:
The invention changes the reactor configuration parameters rather than particle properties. By modifying the reactor structure (adding internal walls and circulation paths), it enables the use of BFB-appropriate particle sizes without requiring excessively large bed volumes
4Reliability
If standard gas fluidization nozzles are used to prevent long-range entrainment, then bed performance is maintained, but directed momentum to specific bed portions cannot be achieved
Solution Approach 1:
The splash generator provides localized, directed gas injection to specific portions of the bed, creating local quality variations in gas velocity and direction. This allows directed momentum to be applied where needed while maintaining overall bed performance through the controlled splashzone
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 configuration enables efficient, controlled reaction rates, reduced erosion, and improved heat transfer, while minimizing capital and operational costs, by allowing circulation of large BFB particles without high gas velocities.
Implementation Method 1
a splashgenerator configured to impart a directed momentum to a particular portion of the bed, causing an active, controllable circulation/movement of bed solids within the bed
Implementation Method 2
Typical fluidized bed reactors are based on either so-called circulating fluidized bed (CFB) or so-called bubbling fluidized bed (BFB) designs
Implementation Method 3
heat exchange (e.g., to heat steam) occur
Implementation Method 4
improved heat transfer
Data Source
AI summary
Various aspects provide for a fluidized bed reactor comprising a container having a bed of bed solids and a splashgenerator configured to impart a directed momentum to a portion of the bed solids. A bedwall may separate the bed solids into first and second reaction zones, and the directed momentum may be used to transfer bed solids from one zone to the other. A return passage may provide for return of the transferred bed solids, providing for circulation between the zones. A compact circulating bubbling fluidized bed may be integrated with a reactor having first and second stages, each with its own fluidization gas and ambient. A multistage reactor may comprise a gaswall separating at least the gas phases above two different portions of the bed. A gaslock beneath the gaswall may provide reduced gas transport while allowing bed transport, reducing contamination.