Sewage Cellulosic Feedstock Purification via Segmented Impurity Removal
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Solution Overview
Problem
Current methods for producing cellulosic feedstock from sewage are inefficient in removing impurities like sand, minerals, and dirt, resulting in suboptimal compositions for downstream products such as textiles, biofuels, and paper products.
Innovation Solution
A method involving the trapping of solid portions from sewage suspensions using devices like netting or centrifugation, followed by removal of sand through centrifugation or Dissolved Air Flotation, and mineral removal using deionized water or acid washes, to produce a cellulosic feedstock with specific composition ranges suitable for various industrial applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional methods are used to produce cellulosic feedstock from sewage, then the production process is simpler, but the impurity removal efficiency is low resulting in suboptimal composition
Solution Approach 1:
The patent divides the impurity removal process into distinct sequential stages: sand removal (via centrifugation or DAF), mineral removal (via deionized water or acid washes), and dirt removal (via filtration). This segmentation allows each stage to target specific impurities with optimized methods, achieving high removal efficiency while maintaining manageable process complexity through modular design
Solution Approach 2:
The patent employs parameter changes by adjusting pH levels during acid washes to enhance mineral removal, modifying centrifugation speed and flotation conditions to optimize sand separation, and controlling filtration parameters to maximize dirt removal. These parameter optimizations enable high manufacturing precision without requiring overly complex equipment
2Manufacturing precision
If multiple removal steps are applied to increase cellulose content, then the feedstock quality improves, but the processing time increases
Solution Approach 1:
The patent performs preliminary sand removal via centrifugation or DAF before the main cellulose extraction process. By removing sand early, subsequent processing steps can focus on cellulose recovery without interference from sand particles, reducing overall processing time while achieving high cellulose content in the final feedstock
Solution Approach 2:
The patent implements continuous processing where removal steps operate in sequence without complete interruption between stages. The solid portion flows continuously through sand removal, mineral removal, and filtration stages, maintaining productive action throughout and minimizing idle time while achieving high cellulose concentration
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 method effectively reduces sand and mineral content to less than 5% and dirt content to less than 25%, producing a cellulosic feedstock with a cellulose content of 40-99% and caloric value of 12000-37000 kJ/kg, enhancing the quality and versatility of derived products like textiles, biofuels, and paper.
Implementation Method 1
removing sand from the solid portion by centrifugation
Implementation Method 2
removing sand from the solid portion by Dissolved Air Flotation
Implementation Method 3
removing a mineral from the solid portion by use of steam or a chemical wash
Data Source
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AI summary
A cellulosic feedstock composition including an oil content of up to 15% of the composition, a cellulose content of 40-99% of the composition, a hemicellulose content of 2- 20% of the composition, a lignin content of less than 15% of the composition, a nitrogen containing organic compound content of less than 20% of the composition, a protein containing organic compound content of less than 20% of the composition, a mineral content of less than 5% of the composition, a sand content of less than 5% of the composition, and a dirt content of less than 25% of the composition.