Waste Paper Re-pulping Odor Reduction via Pressure Vessel Cooling
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Solution Overview
Problem
Recycled waste paper often emits undesirable odorous compounds during processing, which is a challenge in the production of paper products, as existing methods do not effectively reduce odor emissions.
Innovation Solution
A method involving introducing waste material and dilution water into a pressure vessel, where it is re-pulped at elevated temperatures and pressures, followed by cooling with cooling water to reduce odor emissions, using a specific water ratio to minimize odor release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If waste material is re-pulped at elevated temperature to break down contaminants, then cleaning effectiveness is improved, but odor emission increases
Solution Approach 1:
The patent utilizes phase transition of water from liquid to vapor and back to liquid. Water is heated to boiling point to create steam under pressure for effective cleaning, then rapidly cooled to condense the steam and reduce odor emission, allowing the system to achieve both thorough cleaning and odor control
Solution Approach 2:
The patent dynamically changes temperature and pressure parameters during the re-pulping process. It elevates temperature to at least 100°C for effective contaminant breakdown, then reduces temperature to below 60°C to minimize odor emission, achieving both cleaning effectiveness and odor control through parameter optimization
2Object-generated harmful factors
If cooling water is added to reduce odor emission, then odor control is improved, but water consumption increases
Solution Approach 1:
The patent uses phase transition of cooling water from liquid to vapor when it contacts hot surfaces, utilizing the latent heat of vaporization to efficiently absorb heat and reduce odor emission. This phase change mechanism provides superior cooling efficiency compared to simple liquid cooling, reducing the total water quantity needed
Solution Approach 2:
The patent replaces conventional mechanical cooling systems with a thermal field-based cooling approach using steam condensation. The latent heat release during condensation provides intense localized cooling that is more efficient than mechanical cooling methods, reducing overall water consumption while maintaining odor control
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 odor emissions and produces a treated waste material suitable for manufacturing various paper products, such as tissue and packaging, by breaking down odorous compounds and contaminants.
Implementation Method 1
re-pulping the waste paper in the pressure vessel at an elevated processing temperature of at least about 100°C (212°F)
Implementation Method 2
introducing cooling water into the pressure vessel so as to cool the treated waste material in the pressure vessel to a discharge temperature less than about 60°C (140°F) and reduce odor emitted
Data Source
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AI summary
A method for recycling waste material including waste paper comprises the steps of introducing the waste material into a pressure vessel, re-pulping the waste paper in the pressure vessel at an elevated processing temperature and pressure to form a treated waste material including substantially re-pulped waste paper, thereafter introducing cooling water into the pressure vessel so as to cool the treated waste material in the pressure vessel to a discharge temperature below the elevated processing temperature and reduce odor emitted by the treated waste material, and thereafter discharging the treated waste material from the pressure vessel. The recovered paper pulp fraction is suitable as a feedstock in the manufacture of a variety of paper products including paper tissue and paper towel products.