Conical Grid Structure for Fluidized Bed Gasifier Thermal Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing grid structures in fluidized bed gasifiers are complex, expensive, and prone to mechanical wear, leading to frequent replacements and high manufacturing costs, especially in large-scale applications, due to thermal expansion issues and back-flow phenomena.
Innovation Solution
A conical grid structure with concentric plate rings supported by a separate beam structure that allows radial thermal expansion and uses a flexible sealing mechanism, enabling the use of cheaper materials and simpler manufacturing processes while maintaining mechanical durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a known grid structure with concentric slanted plate rings and separate spacers is used, then air distribution is achieved, but the structure becomes complex and expensive to manufacture
Solution Approach 1:
The patent merges the grid plates and support structures into a single integrated component. The grid plates are directly supported by the wind box walls through integrated support ribs, eliminating the need for separate spacers and complex assembly of multiple parts. This integration simplifies the overall structure and reduces manufacturing costs while maintaining the necessary air distribution functionality.
Solution Approach 2:
The wind box walls serve multiple functions: they provide structural support for the grid plates, act as air distribution channels, and eliminate the need for separate support structures. The integrated design makes the wind box a multi-functional component that reduces overall system complexity and manufacturing requirements.
2Temperature
If bolts made of heat-resistant steel are used to fix plates, then the grid can withstand high temperatures, but manufacturing costs increase
Solution Approach 1:
The patent removes the expensive heat-resistant steel bolts from the design by adopting a bolt-less integrated structure. The grid plates are directly supported by the wind box walls through integrated support ribs, eliminating the need for separate fastening components. This extraction of unnecessary components reduces manufacturing costs while the integrated structure maintains structural integrity at high temperatures.
3Strength
If a thick plate ring is used to support the grid, then structural strength is improved, but thermal expansion causes sealing problems between flanges
Solution Approach 1:
The patent removes the thick plate ring that caused sealing problems and replaces it with integrated support ribs that are part of the wind box structure. This eliminates the thermal expansion mismatch between separate components and the flange sealing area, preventing sealing issues while maintaining structural strength.
Solution Approach 2:
The support structure is merged with the wind box walls, creating an integrated design where the support ribs are formed as part of the wind box structure. This eliminates the interface between separate components that caused sealing problems, allowing thermal expansion without compromising the flange seal integrity.
4Ease of operation
If the grid is made as a self-bearing type, then installation is simplified, but the structure becomes very heavy in large scale applications
Solution Approach 1:
The patent merges the grid support function with the wind box structure. The wind box walls serve as the bearing structure for the grid plates through integrated support ribs, eliminating the need for a separate heavy self-bearing grid structure. This reduces the overall weight while maintaining installation simplicity as the grid plates are directly supported by the existing wind box framework.
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 new grid structure is more economical, mechanically durable, and reduces unnecessary shutdowns by minimizing thermal stress on support structures, allowing for easier production and reduced maintenance costs in large-scale gasifiers.
Implementation Method 1
The radial beams are borne at their outer ends onto the walls of the wind box by means of supports which are fixed onto the walls of the wind box, preferably by welding. The fixing of the beams to the supports is accomplished by means of a sliding shaft, which allows thermal expansion of the beam structure in the direction of the radius of the grid
Implementation Method 2
Most preferably this is carried out by welding a thin sealing plate provided with a flexible bellows between the grid and the wall of the wind box. This allows thermal expansion of the grid in the radial direction
Data Source
Figure 1
Figure 2~5
AI summary
The present invention relates to a grid structure for a fluidized bed gasifier. The gasifier comprises an atmospheric or pressurized gasification reactor defined by vertical walls, wherein a fluidized bed is maintained, a wind box located in the lower part of the gasifier below the reactor, and a grid that is arranged between the reactor and the wind box and comprises a number of substantially concentric plate rings. A first set of concentric plate rings are located at different levels to form a conical downwards tapering structure, the supporting structure of which comprises an annular supporting beam below the set of rings and radial supporting beams extending therefrom, which are supported onto the walls of the wind box. The grid also comprises a second set of rings formed by plate rings arranged between the first rings and provided with nozzle openings for leading air or other fluidizing gas from the wind box into the reactor.