Fluidized Bed Particle Flow Control Arrangement
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Solution Overview
Problem
Existing methods for controlling the flow of solid particles in fluidized bed reactors, such as circulating fluidized bed boilers, face challenges with mechanical flow control devices getting stuck and lack of independent control over sub flows, leading to inefficiencies in heat exchange and particle distribution.
Innovation Solution
A non-mechanical control arrangement using a vertical inlet pipe with a branch and a horizontally extending intermediate pipe, where the first sub flow is directed to a first outlet chute via a side wall opening and the second sub flow is directed to a second outlet chute via a vertically extending riser pipe, allowing for independent control of the flow ratio by adjusting fluidizing gas velocities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If mechanical flow control devices (plug valve, throttle valve, rotary lock) are used to control the ratio of sub flows, then flow control capability is improved, but device complexity increases and reliability decreases due to particles getting stuck between moving parts
Solution Approach 1:
The patent replaces mechanical flow control devices with a fluidized bed system that uses gas flow to control particle distribution. Instead of mechanical valves and locks that particles can jam, the invention uses a fluidizing gas introduced at the bottom of the chamber to create a fluidized bed that passively directs particles to different outlets based on gas velocity and distribution, eliminating moving parts and mechanical failure modes.
Solution Approach 2:
The invention introduces a gas flow system at the bottom of the flow control chamber that fluidizes the particle bed. By controlling the gas velocity and distribution through nozzles or distributors, the system pneumatically controls particle flow paths to different outlets, replacing mechanical actuation with pneumatic control of the fluidized bed state.
2Ease of operation
If separately fluidized areas with division walls are used in a chamber, then independent control of sub flows is improved, but device complexity increases and particle stagnation occurs in corner areas
Solution Approach 1:
The invention divides the flow control chamber into multiple fluidized bed zones with separate gas introduction systems. Each zone can be independently fluidized and controlled through its own gas flow rate, allowing independent control of particle flow to different outlets without requiring physical division walls that create stagnant corners.
Solution Approach 2:
Instead of using vertical division walls that create three-dimensional stagnant zones in corners, the invention uses horizontal gas distribution layers and controls particle flow in the horizontal plane through differential gas velocities, effectively managing flow separation without creating dead zones in vertical corners.
3Device complexity
If a non-mechanical flow controlling arrangement with a fluidized bed and outlets at opposite ends is used, then device complexity is reduced, but controllability of the ratio of sub flows becomes weak
Solution Approach 1:
The invention introduces localized gas distribution systems with multiple nozzle arrays or distributors positioned at different locations and orientations within the fluidized bed. By independently controlling gas flow to different local zones, the system can precisely control particle flow ratios to opposite outlets while maintaining a relatively simple overall structure without complex mechanical components.
Solution Approach 2:
The invention uses dynamic control of gas flow rates and velocities to actively regulate particle distribution ratios. By dynamically adjusting gas flow parameters in response to desired outlet flow ratios, the system achieves precise controllability through the dynamic behavior of the fluidized bed rather than fixed mechanical configurations.
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
Enables precise control of the ratio of sub flows from 1:0 to 0:1, preventing gas lock formation and ensuring efficient heat exchange by separating the outlet chute connections vertically and horizontally, thus improving controllability and reducing stagnation.
Implementation Method 1
a fluidizing device for directing controlled first and second sub flows formed from the flow of solid particles to the first and second outlet chutes, respectively
Data Source
AI summary
An arrangement for controlling a flow of solid particles includes a vertical inlet pipe for directing solid particles downwards and having a bottom at a level L0, a first outlet chute and a second outlet chute in particle flow connection with the vertical inlet pipe and a fluidizing device for directing controlled first and second sub flows to the first and second outlet chutes. The arrangement includes a branch in particle flow connection with an opening on a side wall of the vertical inlet pipe for directing the first sub flow of solid particles to the first outlet chute and a horizontally extending intermediate pipe for directing the second sub flow of solid particles to the second outlet chute. The intermediate pipe includes at least one nozzle feeding fluidizing gas to the intermediate pipe and has a first end in particle flow connection with the bottom of the inlet pipe.