Subcritical CO2 Devolatilization of Sponge Blocks
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Solution Overview
Problem
Current methods for removing volatile organic compounds from sponges, such as steam-stripping and post-polymerization, are inefficient, costly, and can deform the sponge material, while existing devolatilization methods fail to meet stringent EU and national standards for residual VOC content.
Innovation Solution
The use of subcritical carbon dioxide as a solvent to extract VOCs from sponges under controlled subcritical conditions, enhancing solubility and diffusivity, and allowing for efficient removal of VOCs without deforming the sponge material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If steam-stripping method is used to remove volatile organic compounds from sponges, then the removal efficiency of VOCs is improved, but the energy consumption increases and the sponge material may deform
Solution Approach 1:
The patent changes the physical parameters of the extraction medium by using supercritical carbon dioxide instead of steam. By controlling temperature and pressure to achieve supercritical state, the medium gains enhanced solubility and diffusivity properties, allowing effective VOCs removal at lower energy consumption without causing material deformation
Solution Approach 2:
The patent utilizes the phase transition properties of carbon dioxide between supercritical and gaseous states. By adjusting pressure and temperature, CO2 transitions to supercritical phase for extraction, then returns to gaseous phase for easy separation, eliminating the need for high energy input required by steam-stripping methods
2Manufacturing precision
If post-polymerization method is used to remove volatile organic compounds, then the residual monomer content is reduced, but the process complexity and cost increase
Solution Approach 1:
The patent directly extracts volatile organic compounds from the sponge matrix using supercritical carbon dioxide, removing the need for additional polymerization steps. This extraction approach simplifies the overall process while achieving low residual monomer content, contrasting with the multi-step post-polymerization method
3Object-generated harmful factors
If steam-stripping method is used for devolatilization, then volatile organic compounds are removed, but the equipment investment and operational cost increase
Solution Approach 1:
The patent employs carbon dioxide, an inexpensive and readily available gas, as the extraction medium. The CO2 is used in supercritical state for extraction then easily separated and can be recycled or vented, eliminating the need for expensive specialized equipment and high operational costs associated with steam-stripping 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
Achieves a removal rate of up to 99% of VOCs, meeting stringent standards with low energy consumption and no residual solvent, making it environmentally friendly and cost-effective.
Implementation Method 1
The use of subcritical carbon dioxide as a solvent to extract VOCs from sponges under controlled subcritical conditions, enhancing solubility and diffusivity
Implementation Method 2
enhancing solubility and diffusivity, and allowing for efficient removal of VOCs
Data Source
Figure 1
AI summary
Disclosed is a method of removing volatile organic compounds from sponges by using supercritical/subcritical fluid. The method includes the following steps: placing the sponge block to be treated in the extraction kettle; feeding the critical flow medium into the extraction kettle; performing extraction under the supercritical or subcritical conditions of the critical flow medium; releasing pressure to normal pressure after extraction; and separating to obtain devolatilized sponge. The volatile removal device used in the disclosure is a supercritical extraction equipment, which can adopt static extraction or dynamic extraction or a combination of the two. CO2releases pressure in the separating kettle after contacting the sponge to be treated in the device for mass transfer for a certain period, when the static extraction devolatilization is carried out.