Continuous Fluidized Bed Reactor With Isolated Freeboards
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Materials with cohesive characteristics, such as starch, tend to form aggregates during fluidization in tubular zones, leading to severe channeling and incomplete conversion in existing fluidized bed reactors, making them difficult to process effectively.
Innovation Solution
A continuous fluidized bed apparatus with multiple cells connected by apertures for horizontal flow, isolated freeboards, and filter sticks with blow back valves to maintain a constant pressure difference, ensuring simultaneous blow back and efficient fluidization of cohesive materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If tubular zones are used to minimize channeling, then heat transfer characteristics improve, but cohesive materials still form aggregates and severe channeling occurs
Solution Approach 1:
The reactor is divided into multiple tubular zones separated by vertical weir plates, with each tube operating as an individual fluidized bed. This segmentation reduces the cross-sectional area of each bed, improving heat transfer characteristics and reducing channeling. The weir plates create discrete compartments that prevent aggregate formation across the entire cross-section.
Solution Approach 2:
Filter sticks are introduced as intermediary elements within the freeboard space above each tubular zone. These filter sticks capture aggregates before they can form severe channeling patterns. The blowback valves periodically reverse gas flow through the filter sticks to dislodge and remove accumulated aggregates, maintaining fluidization quality.
2Reliability
If filter sticks with blow back valves are added to prevent channeling, then fluidization of cohesive materials improves, but device complexity increases
Solution Approach 1:
The blowback valves operate periodically rather than continuously, reversing gas flow through the filter sticks at intervals to dislodge aggregates. This periodic action maintains fluidization quality without requiring complex continuous control systems. The constant pressure difference (no more than 1000 Pa) between freeboards ensures automatic operation and simplifies control.
3Productivity
If multiple cells are connected for continuous fluidization, then productivity increases, but maintaining constant pressure difference becomes more difficult
Solution Approach 1:
The system maintains constant pressure difference (no more than 1000 Pa) between freeboards of adjacent cells through the equipotentiality principle. This ensures uniform fluidization conditions across all cells in the continuous reactor, allowing scalable productivity improvement without complex pressure control for each individual cell.
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 setup prevents channeling, achieves uniform residence times, and enhances heat transfer characteristics, allowing for complete conversion and efficient processing of difficult-to-fluidize materials like starch, with improved homogeneity and product quality.
Implementation Method 1
In general, in fluidized systems a solid phase is suspended in an upwardly moving gas stream
Implementation Method 2
High turbulence existing in a fluidized bed provides high heat transfer characteristics
Implementation Method 3
The fluidized bed in this set up moves over the weir plates by a spill overflow modus
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention is concerned with an apparatus and method for continuous fluidization which comprises at least two cells connected by an aperture permitting the solid material to be introduced into the next downstream cell by fluidized horizontal flow, an isolated freeboard within each cell, at least two filter sticks contained within the isolated freeboard of each cell, and at least one blow back valve contained within each filter stick. The apparatus allows processing of materials that are typically difficult to fluidize by maintaining a substantially constant pressure difference between each isolated freeboard.