Solvent Recovery in Lumber Treatment Using RF Energy
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Solution Overview
Problem
Current methods for treating lumber with preservatives, such as waterborne and LOSP processes, face issues like high solvent uptake, swelling, environmental concerns, and inefficiency due to solvent loss and high costs, particularly with non-polar solvents like Stoddard solvents which are difficult to recover and recycle.
Innovation Solution
Incorporating a dielectric loss enhancing additive with low dielectric loss solvents, such as Stoddard solvents or chlorinated hydrocarbons, to enhance RF energy absorption and recovery, allowing for efficient solvent recovery and reuse while minimizing environmental impact and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If non-polar organic solvents like Stoddard solvents are used for LOSP processes, then solvent uptake is reduced and swelling is avoided, but solvent recovery becomes difficult and environmental impact increases
Solution Approach 1:
An emulsifier is introduced as an intermediary substance that enables the non-polar solvent to form a stable emulsion with water during the treatment process. This emulsion allows the solvent to be effectively recovered through water extraction after treatment, resolving the difficulty of solvent recovery while maintaining the low uptake and no-swelling benefits of non-polar solvents
Solution Approach 2:
The invention changes the physical state and properties of the solvent system by creating an emulsion. The non-polar solvent is transformed from a separate phase that is difficult to recover into an emulsified state where it can be easily separated and recovered with water, thereby improving the ease of manufacture and solvent recovery
2Ease of manufacture
If waterborne preservatives are used, then inexpensive inorganic biocides can be used, but substantial uptake is required and re-drying is costly
Solution Approach 1:
The invention changes the nature of the treating fluid from a waterborne solution to a solvent-based LOSP formulation with emulsification capabilities. This parameter change reduces the solvent uptake from 150-600 litres per cubic metre to around 30-40 litres per cubic metre, eliminating the need for costly re-drying while still allowing the use of effective biocides
3Stability of the object's composition
If LOSP processes use non-polar solvents, then swelling is avoided and uptake is low, but all solvent escapes into the atmosphere causing environmental issues
Solution Approach 1:
The emulsifier acts as a mediator that enables the non-polar solvent to be captured by water through emulsion formation. After treatment, the emulsified solvent is recovered with the water phase, preventing it from escaping into the atmosphere. This resolves the environmental harm while maintaining the dimensional stability benefits of using non-polar solvents
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 enables effective and cost-efficient recovery of solvents from treated lumber, reducing environmental impact and solvent usage, while maintaining the physical properties of the lumber without causing swelling or shrinkage, thus offering a sustainable and economical treatment process.
Implementation Method 1
treating a substrate with a composition including a dielectric loss enhancing additive
Data Source
AI summary
The invention relates to compositions for, and methods of, delivering treatment compounds to lignocellulosic substrates, wherein the solvent is recovered using RF energy.