Membrane Reactor PVDF Polymerization Without Bubbles or Emulsifiers
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Solution Overview
Problem
Conventional polymerization of vinylidene fluoride in stirred-tank reactors is inefficient due to high mechanical energy input, mass transfer limitations, and the use of environmentally harmful fluoroemulsifiers, with safety concerns arising from high pressures and flammable gases.
Innovation Solution
A continuous process using a polymerization reactor with a hydrophobic membrane separating a monomer space and a polymerization space, allowing vinylidene fluoride to pass into an aqueous phase at different pressures, eliminating the need for bubble formation and fluoroemulsifiers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional stirred-tank reactors are used for polymerization, then the phase interface between gaseous monomer and aqueous phase can be achieved through bubble formation, but high mechanical energy input is required which is inefficient for phase interface formation
Solution Approach 1:
The patent replaces the mechanical stirring system with a membrane-based gas transfer system. Gas-permeable membranes allow direct diffusion of gaseous vinylidene fluoride into the aqueous polymerization phase without requiring mechanical bubble formation, thereby eliminating high mechanical energy input while maintaining efficient mass transfer.
Solution Approach 2:
The patent introduces gas-permeable membranes as an intermediary between the gaseous monomer phase and the aqueous polymerization phase. These membranes facilitate direct gas transfer and phase interface formation without mechanical agitation, solving the energy efficiency problem while enabling effective monomer dissolution.
2Quantity of substance
If high pressures of 10-300 bar or higher are used to increase monomer solubility in water, then mass transfer limitation is reduced, but additional energy input for gas compression is required and safety problems arise due to large amounts of flammable gas at high pressure
Solution Approach 1:
The patent changes the pressure parameter distribution by using gas-permeable membranes to enable effective mass transfer at lower pressures. The membrane structure facilitates monomer diffusion into the aqueous phase without requiring high compression pressures, thereby reducing energy input while maintaining adequate solubility and reaction efficiency.
Solution Approach 2:
The patent replaces mechanical gas compression with membrane-based gas transfer. Instead of using high-pressure compression to increase monomer solubility, the gas-permeable membranes enable direct diffusion and phase transfer at lower pressures, eliminating the need for high-energy gas compression while ensuring adequate monomer availability for polymerization.
3Quantity of substance
If conventional stirred-tank reactors are used with high pressure, then monomer solubility is increased, but safety problems occur due to large amounts of flammable gas at high pressure and high temperature within the reactor
Solution Approach 1:
The patent replaces the conventional high-pressure stirred-tank system with a membrane-based reactor system operating at lower pressures. Gas-permeable membranes enable effective mass transfer without high-pressure compression, thereby maintaining monomer solubility while significantly reducing the safety risks associated with storing and processing large amounts of flammable vinylidene fluoride gas at high pressure and temperature.
4Productivity
If conventional production of PVDF employs fluoroemulsifiers, then polymerization can proceed in aqueous phase, but environmental persistence and health hazards are caused
Solution Approach 1:
The patent extracts and eliminates fluoroemulsifiers from the polymerization system by using gas-permeable membranes to enable direct gas-liquid mass transfer. The membrane-based system allows vinylidene fluoride to dissolve and polymerize in the aqueous phase without requiring fluoroemulsifiers, thereby maintaining polymerization efficiency while removing the source of environmental persistence and health hazards.
Solution Approach 2:
The patent converts the previously harmful role of fluoroemulsifiers into a beneficial membrane-based system. By using gas-permeable membranes, the system achieves effective phase transfer and polymerization without harmful chemicals, turning the problem of emulsifier toxicity into an opportunity for cleaner, more sustainable polymerization.
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
This process achieves efficient polymerization with reduced energy consumption, avoids harmful emulsifiers, and ensures homogeneous reaction conditions, leading to high conversion and product quality without the need for high pressures or mechanical stirrers.
Implementation Method 1
the polymerization reactor comprises a monomer space and a polymerization space separated from the monomer space by a preferably hydrophobic membrane
Implementation Method 2
the vinylidene fluoride passes into the aqueous phase
Data Source
AI summary
The present invention relates to a process for producing polyvinylidene fluoride by polymerization of vinylidene fluoride, in particular using a polymerization reactor comprising a membrane.