Screw Drying and Classification of Biomass Fuel Chips
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Solution Overview
Problem
Biomass fuel chips require drying to a moisture content of 10% to 15% for efficient gasification power generation, but existing drying devices generate fine powder and necessitate additional sieving, and large or small chips cause operational issues in gasification furnaces.
Innovation Solution
A drying device with a screw blade, opening portion, and collecting portion that conveys and classifies biomass fuel chips using warm air, featuring a shaftless screw blade and adjustable opening sizes to facilitate simultaneous drying and sieving.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a rotary drying device is used to dry biomass fuel chips, then drying efficiency is improved, but fine powder is generated in large quantities
Solution Approach 1:
The patent combines the drying function and classification function into a single integrated device. The rotary drying device is equipped with a classification mechanism that separates fine powder from dried chips during the drying process, eliminating the need for separate sieving operations and reducing fine powder loss.
Solution Approach 2:
The classification mechanism divides the dried material stream into different size fractions using screens or classifiers. This segmentation allows fine powder to be separated from properly sized chips, preventing fine powder from being redistributed and reducing overall fine powder generation in the final product.
2Manufacturing precision
If biomass fuel chips are dried using conventional methods, then moisture content is reduced, but additional sieving equipment is required
Solution Approach 1:
The patent integrates the classification function directly into the drying device structure. The classification mechanism is built into the dryer body, allowing simultaneous drying and size classification in one unit, thereby eliminating the need for separate sieving equipment and reducing overall system complexity.
Solution Approach 2:
The drying device is designed to perform multiple functions: drying biomass chips to the required moisture content and simultaneously classifying them by size. This multi-functionality reduces the number of separate equipment units needed and simplifies the overall manufacturing process.
3Ease of operation
If large-sized biomass fuel chips are used, then conveyance in gasification furnace is improved, but burning efficiency decreases
Solution Approach 1:
The classification mechanism allows for dynamic adjustment of chip size distribution. By controlling the opening size of the classification screen, the system can optimize chip dimensions to achieve the right balance between conveyance stability and burning efficiency, ensuring chips are neither too large nor too small.
4Productivity
If small-sized biomass fuel chips are used, then burning speed increases, but abnormal temperature rise occurs in gasification furnace
Solution Approach 1:
The classification mechanism provides dynamic control over chip size distribution, preventing excessive fine particles from entering the gasification furnace. By adjusting the classification screen opening, the system maintains optimal chip size that ensures controlled burning speed without causing abnormal temperature rises, thus improving operational reliability.
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 device effectively dries and classifies biomass fuel chips, reducing fine powder generation and ensuring appropriate chip size for efficient gasification, with integrated dust removal and temperature stabilization.
Implementation Method 1
conveys the material to be processed by sliding the material to be processed over the opening portion
Implementation Method 2
the material to be processed smaller than the opening is caused to pass through the opening and is classified by the collecting portion
Implementation Method 3
dries the material to be processed by warm air
Data Source
Figure 1(a)~1(b)
Figure 2(a)~2(c)
Figure 3
AI summary
[Problem] Provided is a drying device and a drying method that convey a material to be processed by sliding it over an opening portion under a warm air atmosphere, and thus, the material to be processed smaller than an opening is caused to pass through the opening and is classified while being continuously dried by a collecting portion. [Solution] A drying device dries a material to be processed by warm air. The drying device includes: a screw blade; an opening portion that is arranged below the screw blade and has an opening; and a collecting portion arranged below the opening portion. Rotation of the screw blade conveys the material to be processed by sliding the material to be processed over the opening portion, and the material to be processed smaller than the opening is caused to pass through the opening and is classified by the collecting portion.