Multistage Expanded Bed Heat Exchanger for High Gas Pressure
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Solution Overview
Problem
Conventional fluidized bed indirect-contact heat exchangers are impractical for high gas pressure applications and fail to promote mass-flow patterns of particles, leading to inefficiencies and heat loss, making them unsuitable for particle-based central receiver concentrated solar power systems and power generation.
Innovation Solution
An expanded bed direct-contact system with a multistage chamber and internal perforated plates, incorporating a particle feeder and downcomers for efficient particle and fluid flow, allowing counter-flow heat exchange and addressing particle carryover issues, integrated into recirculating heat exchangers and chemical reactors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If conventional fluidized bed indirect-contact heat exchangers are used, then heat exchange between particles and fluid can be achieved, but the system cannot operate under high gas pressure conditions and fails to promote mass-flow patterns of particles
Solution Approach 1:
The heat exchanger is divided into multiple stages with internal perforated plates separating each stage. This segmentation allows the system to handle high gas pressure by distributing the pressure management across multiple controlled zones, while each stage maintains proper particle-fluid contact for efficient heat exchange.
Solution Approach 2:
Downcomers are introduced as intermediary structures that facilitate mass-flow patterns of particles between stages. These downcomers act as conduits that guide particle movement, ensuring reliable particle circulation and heat exchange functionality under high gas pressure conditions.
2Productivity
If conventional FBIDHX designs are used, then heat recovery from solid particles can be achieved, but particle carryover with gas occurs and mass-flow pattern is not promoted
Solution Approach 1:
The multistage design with internal perforated plates creates distinct zones that separate particle residence areas from gas exit areas. This segmentation prevents particle carryover by containing particles within the staged compartments while allowing clean gas to pass through the perforated plates and exit.
Solution Approach 2:
The downcomers, which could be seen as additional structural complexity, actually serve to convert potential harmful particle entrainment into beneficial mass-flow patterns. By providing dedicated particle return pathways, they ensure particles flow back to the heat exchange zones in a controlled manner, improving overall heat exchange efficiency.
3Stability of the object's composition
If multiple downcomers are incorporated to promote mass-flow pattern, then particle circulation is improved, but device complexity increases
Solution Approach 1:
The downcomers are integrated with the internal perforated plate structure, merging the particle circulation function with the stage separation function. This combination reduces overall device complexity by eliminating the need for separate, standalone downcomer structures while still achieving stable mass-flow patterns.
Solution Approach 2:
The internal perforated plates serve multiple functions: they separate stages for pressure management, facilitate gas flow between stages, and work in conjunction with downcomers to establish mass-flow patterns. This multi-functionality reduces the need for additional specialized components, simplifying the overall device structure.
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
Enhances heat transfer efficiency, reduces energy consumption, and enables effective operation under high gas pressure conditions, suitable for power generation and industrial heat processing applications.
Implementation Method 1
Heat exchange takes place in a multistage expanded bed chamber... the heated particles fall through the plurality of vertically-arrayed stages and exchange thermal energy with the stream of cool fluid
Implementation Method 2
particle-to-working fluid counter-flow direct-contact system which can be used as a particle-based heat exchanger
Implementation Method 3
Fluidized bed (FB) reactors, where solid particles are held in suspension by an up-rising gas stream to form a liquid-like gas-solid mixture
Implementation Method 4
the heated particles fall through the plurality of vertically-arrayed stages
Data Source
AI summary
The expanded bed direct-contact system uses a multistage expanded bed chamber for heat exchange between heated particles, falling under the force of gravity, and an upwardly directed stream of cool fluid. As the heated particles fall through a plurality of vertically-arrayed stages of the multistage expanded bed chamber and exchange thermal energy with the stream of cool fluid, a stream of heated fluid, and a volume of cooled particles, are produced. Porous plates are respectively received within the stages of the multistage expanded bed chamber for increasing residence time of the particles, and the porous plates, as well as the plurality of stages, are connected to one another by a plurality of downcomers, each also formed from a porous material.