Fluidized Bed Reactor for Trifluoroethylene Production
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Solution Overview
Problem
Existing methods for producing trifluoroethylene (HFO-1123) from 1,1,1,2-tetrafluoroethane (HFC-134a) face challenges such as low conversion efficiency, formation of by-products like low molecular weight hydrocarbons and polymer carbon, and instability due to hot spots and poor heat removal efficiency when using a fixed bed reactor.
Innovation Solution
A method involving a fluidized bed reactor where HFC-134a flows through a particulate solid reactant layer with an average particle size of 1 µm to 5,000 µm, using metal oxides or carbonates like sodium, potassium, or calcium as catalysts, to achieve high conversion and selectivity while minimizing by-product formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a fixed bed reactor is used with solid reactant particles, then the reaction can proceed with HFC-134a, but the degree of conversion of the solid reactant is low due to difficulty in uniform mixing and contact
Solution Approach 1:
The patent applies fluidization technology to transform the static fixed bed into a dynamic fluidized bed. By introducing upward gas flow, the solid reactant particles are suspended and continuously moved, creating dynamic mixing conditions that dramatically improve contact between HFC-134a and the solid reactant, thereby resolving the mixing difficulty and enhancing conversion degree.
Solution Approach 2:
The patent uses gas flow (pneumatics) to fluidize the solid reactant bed. The upward flowing gas suspends the particles and creates intense mixing, allowing uniform contact between the gaseous HFC-134a and solid reactant particles throughout the reactor, thus solving the uniform mixing problem.
2Device complexity
If a fixed bed reactor is used, then the reaction structure is simple, but heat removal efficiency is poor leading to hot spots and side reactions
Solution Approach 1:
The fluidized bed creates dynamic particle movement and continuous mixing, which enhances heat transfer throughout the reactor. The constant motion of particles prevents localized heat accumulation (hot spots) by distributing thermal energy uniformly, thus improving temperature control while maintaining relatively simple reactor structure.
Solution Approach 2:
The patent changes the operational state of the solid reactant from static to fluidized by adjusting gas flow parameters. This parameter change transforms the heat transfer mechanism from conduction-dominated (poor in fixed bed) to convection-enhanced (superior in fluidized bed), effectively eliminating hot spots.
3Productivity
If a fixed bed reactor is used with long contact time, then conversion can be improved, but polymer carbon forms and attaches to the solid reactant surface, remarkably lowering conversion over time
Solution Approach 1:
The fluidized bed creates continuous particle motion and renewal of the reactant surface. This dynamic environment prevents polymer carbon from permanently attaching to and deactivating the solid reactant, as particles are constantly moved and exposed to fresh surfaces, thereby maintaining stable conversion over time.
Solution Approach 2:
The fluidized bed creates periodic contact between reactant molecules and catalytic sites through particle circulation. This periodic action prevents continuous polymer deposition that would occur in static conditions, maintaining catalyst activity and stable production.
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 method achieves high conversion and selectivity of HFC-134a to HFO-1123 with reduced by-product formation, preventing hot spots and maintaining stability over time, making the process more efficient and stable compared to traditional fixed bed reactors.
Implementation Method 1
making a material gas containing HFC-134a to flow through a layer consisting of a particulate solid reactant having an average particle size of from 1 μm to 5,000 μm, to bring the solid reactant and HFC-134a into contact with each other in a state where the layer consisting of the solid reactant is fluidized
Implementation Method 2
the solid reactant contains at least one metal compound selected from the group consisting of a metal oxide and a metal carbonate, and wherein the metal species contained in the metal compound is sodium, potassium, calcium or magnesium
Data Source
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AI summary
To produce trifluoroethylene stably with a high selectivity by reacting 1,1,1,2-tetrafluoroethane with a solid reactant efficiently while formation of by-products such as polymer carbon is suppressed. A material gas containing 1,1,1,2-tetrafluoroethane is made to flow through a layer consisting of a particulate solid reactant having an average particle size of from 1 µm to 5,000 µm to bring the solid reactant and 1,1,1,2-tetrafluoroethane into contact with each other in a state where the layer consisting of the solid reactant is fluidized.