Double-Walled Drum Mixer Drying Organic Waste
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Solution Overview
Problem
Drying processes for organic waste products with high liquid content, such as sewage sludge, are energy-intensive and costly, and existing systems lack efficiency and cost-effectiveness.
Innovation Solution
A drying system utilizing waste heat from various energy sources, including blower compressed air, wastewater heat, and thermal processes, for a three-step drying process involving pre-drying, main drying, and post-drying, with a double-walled drum mixer and air distribution system to optimize energy use and control dry matter content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional drying processes are used for organic waste products with high liquid content, then the material can be dried, but the energy consumption is very high and costs are intensive
Solution Approach 1:
The patent changes the temperature parameters by using waste heat from thermal processes at temperatures up to 850°C, and employs multi-stage drying with decreasing temperature levels (e.g., 850°C → 250°C → ambient) to optimize energy utilization while maintaining high drying efficiency
Solution Approach 2:
The patent utilizes phase transitions of water through multiple drying stages: rapid vaporization at high temperature (850°C), condensation in heat exchangers to recover latent heat, and final evaporation at ambient temperature, thereby efficiently managing energy throughout the drying process
2Productivity
If direct contact drying is used, then drying speed is high, but the equipment becomes complex and expensive
Solution Approach 1:
The patent segments the drying process into three distinct stages (rapid drying at 850°C, intermediate drying at 250°C, and final drying at ambient temperature) with dedicated drying chambers for each stage, allowing optimization of each stage independently while maintaining overall simplicity
Solution Approach 2:
The drying system is designed to handle multiple types of organic waste materials (sewage sludge, biomass, food waste) using the same multi-stage drying process and equipment configuration, thereby reducing the need for specialized equipment for different materials
3Use of energy by moving object
If contact drying with heated surfaces is used, then energy efficiency improves, but the device structure becomes more complex
Solution Approach 1:
The patent implements nested heat exchanger systems where waste heat from high-temperature processes is condensed and used to preheat air for intermediate drying, creating a nested energy recovery structure that maximizes efficiency without proportionally increasing structural complexity
Solution Approach 2:
The patent introduces air as an intermediary heat transfer medium that carries thermal energy between different drying stages and heat exchangers, simplifying the thermal coupling compared to direct liquid-to-surface contact drying systems
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 system achieves significant energy savings, reduces investment costs, and produces a homogeneous dry product with up to 95% dry matter content, being independent of climatic conditions and requiring minimal maintenance, while ensuring dust-free and automatic operation.
Implementation Method 1
waste heat from thermal processes (combustion plants, cement works, pyrolysis plants and biogas plants, etc.)
Implementation Method 2
The drying gas (e.g. combustion gas, air or vapors with temperatures up to 850 °C) flows over the dried material
Implementation Method 3
the medium air, which is extracted from the environment and heated by one or a combination of the following energy sources or their waste heat(s), is used as process air
Data Source
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AI summary
The present invention relates to a system for drying organic waste products; thus, a suitable process, in particular for drying sewage sludge from public, municipal, and industrial wastewater treatment plants (sewage treatment plants), can be carried out on such a system. In an advantageous embodiment, the present invention utilizes the drying steps of pre-drying, main drying, and post-drying. During the drying process, the medium, air, is heated by waste heat.