Rotating Classifier Comb Teeth Prevent Biomass Blockage
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Solution Overview
Problem
The existing rotating classifiers face challenges in accurately classifying biomass and coal mixtures due to blockages caused by biomass, leading to poor combustion performance and increased NOx and UBC emissions, as biomass is easily blown up and fibrous, causing vortex flows that block the classifier's narrow passages, resulting in inaccurate particle size distribution and reduced power generation efficiency.
Innovation Solution
A rotating classifier design featuring comb teeth-like protrusion portions on the rotary classification fins, with a specific gap configuration and support members, that reduces the passage of coarse particles and prevents blockages by utilizing centrifugal force and air flow directionality to separate particles effectively, ensuring high classification performance and preventing biomass blockages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the narrow passage between the fixed member and rotary classification fins is reduced to improve classification accuracy, then particle size distribution improves, but biomass blockages occur more frequently
Solution Approach 1:
The rotary classification fins are segmented into multiple fin portions (first fin portion, second fin portion, third fin portion) with different functions. The first fin portion performs classification, the second fin portion prevents coarse particle intrusion, and the third fin portion prevents biomass blockage by directing airflow. This segmentation allows each segment to optimize for its specific function without compromising overall system performance.
Solution Approach 2:
Different regions of the rotary classification fins have different structural characteristics tailored to local requirements. The fin portions closer to the rotation axis have different geometry and spacing compared to outer portions, allowing optimal classification accuracy in critical zones while maintaining blockage resistance in other areas.
2Manufacturing precision
If the gap between classification fins is reduced to improve classification performance, then particle separation improves, but biomass vortex flows block the passages
Solution Approach 1:
The second fin portion acts as an intermediary structure between the first fin portion (classification) and the third fin portion (airflow control). It prevents coarse particles from intruding into the classification zone while allowing fine particles to pass, and works with the third fin portion to manage biomass airflow patterns.
Solution Approach 2:
The third fin portion is specifically designed to generate controlled airflow that prevents biomass blockage. By utilizing pneumatic forces, it directs air flow to counteract the vortex flows that cause biomass to accumulate and block passages, maintaining clear pathways for particle classification.
3Device complexity
If the rotating classifier structure is simplified to reduce complexity, then manufacturing cost decreases, but classification performance deteriorates
Solution Approach 1:
The rotary classification fins serve multiple functions simultaneously: the first fin portion performs primary classification, the second fin portion prevents coarse particle intrusion, and the third fin portion controls airflow to prevent biomass blockage. This multi-functionality is achieved within a single integrated structure, avoiding the need for separate components for each function.
Solution Approach 2:
Multiple functional elements are merged into a single rotary classification fin structure. Instead of having separate classification fins, coarse particle barriers, and airflow control devices, all these functions are integrated into one rotating component, simplifying the overall device while maintaining performance.
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 proposed design enhances classification accuracy and prevents blockages, maintaining high classification performance and improving combustion efficiency by effectively separating particles and reducing NOx and UBC emissions, thereby enhancing power generation efficiency.
Implementation Method 1
a particle group carried by an air flow is classified by centrifugal force of the rotary classification fins
Data Source
AI summary
[Problem] To provide a rotating classifier which can keep classification performance high and which can prevent blockages caused by biomass and the like.[Means for Resolution] The rotating classifier is characterized in that: comb teeth-like protrusion portions protruding toward a fixed member side are provided on top of rotary classification fins at intervals along the circumferential direction of the rotating classifier fins; a first gap is provided between an upper end portion of each of the comb teeth-like protrusion portions and a lower surface of the fixed member; a second gap formed between a protrusion portion and a protrusion portion adjacent to the protrusion portion is connected to the first gap; and an air stream flowing from the radial outside to the radial inside of the comb teeth-like protrusion portions through the first gap and the second gap is formed due to the rotation of the rotary classification fins.