Fluidized-Bed Boiler Grate Arrangement for Agglomerate Control
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Solution Overview
Problem
Fluidized bed combustion boilers face issues with agglomerate formation over time, limiting the use of challenging fuel specifications and necessitating frequent downtime for maintenance.
Innovation Solution
A grate arrangement with distributed gas feeding means and a control system that alternates between fluidizing gas and booster gas supply to specific subareas of the grate, enhancing operation and preventing agglomerate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single gas supply system is used for the entire grate area, then the system structure is simple, but agglomerates cannot be effectively broken and maintenance downtime increases
Solution Approach 1:
The grate area is divided into multiple subareas, each served by separate gas feeding means and feeding groups. This segmentation allows independent control of gas supply to different regions, enabling targeted agglomerate breaking while maintaining overall system reliability.
Solution Approach 2:
The gas supply system is made dynamic through the ability to switch between fluidizing gas and booster gas supply modes for different feeding groups. The controlling means enables real-time adjustment of gas supply patterns to address varying operational needs, particularly for breaking agglomerates in specific areas.
2Reliability
If booster gas supply is applied to the entire grate area simultaneously, then agglomerate breaking is maximized, but gas consumption and system complexity increase
Solution Approach 1:
Booster gas supply is applied locally to specific subareas where agglomerates are detected or expected, rather than uniformly across the entire grate. This localized approach maintains effective agglomerate breaking while significantly reducing overall gas consumption compared to full-area treatment.
Solution Approach 2:
Instead of applying booster gas continuously or excessively to the entire area, the system uses partial action by targeting only the necessary subareas with feeding groups that are opened to the booster gas supply system when needed.
3Reliability
If the grate is divided into many subareas with separate feeding groups, then targeted agglomerate breaking is improved, but control system complexity increases
Solution Approach 1:
The control system is segmented into multiple feeding groups that can be independently controlled. Each feeding group manages a specific subarea, allowing targeted booster gas application while keeping individual control units relatively simple and manageable.
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 solution effectively maintains the fluidized bed operation by preventing agglomerates, allowing the use of diverse fuels and reducing maintenance needs.
Implementation Method 1
a grate arrangement for use in a fluidized-bed boiler... plurality of gas feeding means for feeding fluidizing gas above the grate... for supplying fluidizing gas therethrough above the grate
Data Source
AI summary
A grate arrangement and a method for use in a fluidized-bed boiler. The arrangement comprises a grate having length and width defining the area of said grate, plurality of gas feeding means being distributed on the area of the grate, a gas supply system connected to the plurality of gas feeding means for supplying fluidizing gas above the grate, and a booster gas supply system connected to at least some of the plurality of gas feeding means for supplying booster gas above the grate. The gas feeding means are grouped in at least two feeding groups, each of which feeding groups is extending only to a subarea of the area of the grate. Controlling means are arranged for controlling the systems so that while at least one of the feeding groups is open to the gas supply system for feeding fluidizing gas above the grate, at least one another of the feeding groups is closed to said gas supply system and open to the booster gas supply system.