Single-Screw Extrusion for Waste Rubber Desulfurization
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Solution Overview
Problem
Current desulfurization processes for waste rubber face issues such as complex structures, high energy consumption, low efficiency, safety hazards, and air pollution, particularly due to the use of high-pressure tanks and spiral desulfurization devices, which also require cumbersome post-processing with open mills leading to unstable quality and high labor intensity.
Innovation Solution
A single-screw extrusion desulfurization and post-processing system that combines thermochemical and shearing functions, featuring a single-screw desulfurization device with a heating structure and a post-processing device with a closed connection, allowing for continuous and efficient desulfurization and post-processing without additional cooling needs, utilizing a full-pin or major-minor thread screw structure to maintain C-C backbone chain integrity and enhance shearing force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If dynamic desulfurization device (high-pressure desulfurization tank) is adopted, then desulfurization can be achieved, but serious pollution, high energy consumption, large labor intensity, instable quality, low efficiency, and safety hazards occur
Solution Approach 1:
The patent replaces the high-pressure mechanical desulfurization system with a single-screw extruder system that uses mechanical shearing and mixing actions. The single-screw structure with specific compression ratios and heating zones achieves desulfurization through controlled mechanical action and temperature management, eliminating the need for high-pressure tanks and associated safety hazards while reducing pollution from auxiliary systems.
2Object-generated harmful factors
If spiral continuous desulfurization device is adopted, then continuous desulfurization production is achieved with low pollution, but large volume, complex structure, difficulty in maintenance, low operation reliability, high operation cost, and high energy consumption occur
Solution Approach 1:
The patent extracts and eliminates the complex spiral conveyor structure from the desulfurization system. By using a single-screw extruder with direct heating and mixing capabilities, the design removes the need for separate spiral conveying mechanisms, multi-stage processing units, and associated complex control systems, thereby simplifying the overall structure while maintaining continuous operation capability.
Solution Approach 2:
The single-screw extruder performs multiple functions within a single integrated device: feeding, heating, shearing, mixing, and extruding. This multi-functional design replaces the need for multiple separate devices (spiral conveyors, heating units, mixing chambers) required in traditional spiral desulfurization systems, reducing structural complexity and improving reliability.
3Productivity
If spiral desulfurization device is adopted, then continuous desulfurization is achieved, but S-S and S-C bonds cannot be broken physically, low desulfurization efficiency occurs
Solution Approach 1:
The patent employs a dynamically designed single-screw extruder with variable pitch and compression ratios along the screw length. The screw geometry creates increasing shear stress and mechanical action in the compression zone, physically breaking S-S and S-C bonds through controlled mechanical force. The dynamic design allows optimization of shearing intensity at different positions to maximize bond breaking efficiency.
4Ease of operation
If three or four open mills are adopted for post-processing, then desulfurized rubber can be processed, but cumbersome processes, large labor intensity, high consumed power, and air pollution occur
Solution Approach 1:
The patent merges the post-processing function directly into the single-screw extruder system. The extruder's mixing and shearing actions in the final zones serve both desulfurization completion and post-processing requirements. This integration eliminates the need for separate open mill operations, simplifying the process flow and eliminating air pollution from open mill dust generation.
Solution Approach 2:
The patent discards the traditional open mill post-processing step entirely. Instead, the single-screw extruder recovers and completes all necessary processing functions within its closed system, delivering final product quality without requiring additional open processing stages that generate pollution and require manual intervention.
5Force
If co-rotating double screw extruder is adopted for post-processing, then high shearing force is achieved, but complex structure, difficulty in production, high production cost, difficulty in maintenance occur
Solution Approach 1:
The patent extracts and eliminates the co-rotating double-screw mechanism from the design. By using a single-screw extruder with optimized geometry (variable pitch, compression zones, heating elements), the design achieves the necessary shearing force through a simpler single-screw mechanism, removing the complexity of synchronized dual-screw systems while maintaining effective mixing and processing capabilities.
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
This system reduces pollution, energy consumption, and operation costs, achieving stable and efficient desulfurization with improved rubber quality, enabling continuous automatic production and reducing the risk of material adherence and explosive hazards, while maintaining the integrity of C-C backbone chains.
Implementation Method 1
a heating structure respectively disposed in the desulfurizing and feeding unit, the desulfurizing unit and the desulfurizing screw
Implementation Method 2
utilizing a full-pin or major-minor thread screw structure to maintain C-C backbone chain integrity and enhance shearing force
Data Source
Figure 1~5
Figure 6~8
AI summary
A single-screw extrusion desulfurization and post-processing system and a method for preparing reclaimed rubber. The single-screw extrusion desulfurization and post-processing system comprises: a single-screw desulfurization device, a single-screw post-processing device and a closed connection device for connecting the single-screw desulfurization device and the single-screw post-processing device, the single-screw post-processing device includes a post-processing feeding unit and a post-processing unit which are connected with each other, and a post-processing screw running through the post-processing feeding unit and the post-processing unit.