Zeolite Membrane Composite for Diene Separation
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Solution Overview
Problem
There is a lack of an effective method for industrially producing a high-purity straight-chain conjugated diene from a mixture containing it and olefin using an inorganic membrane, as existing separation methods are energy-intensive or have limited scope and polymer membranes are prone to degradation.
Innovation Solution
A zeolite membrane composite with a porous support and a faujasite-type zeolite layer containing alkali metals like Na, K, or Cs is used to selectively separate straight-chain conjugated dienes from mixtures with straight-chain olefins, achieving high separation efficiency and purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation or solvent extraction is used to separate straight-chain conjugated diene from mixture, then separation can be achieved, but large amount of energy is required
Solution Approach 1:
The patent employs a zeolite membrane with porous structure having specific pore size (0.3-0.7 nm) that enables selective permeation of straight-chain conjugated diene molecules while excluding other components. The porous structure provides molecular sieving effect that achieves separation without requiring large amounts of energy for heating or solvent circulation.
Solution Approach 2:
The invention uses a composite membrane structure combining an organic porous support with an inorganic zeolite layer. This composite material leverages the mechanical strength of the organic support and the selective separation properties of the inorganic zeolite, achieving both structural integrity and high separation performance with low energy consumption.
2Ease of operation
If polymer membrane is used for separation, then separation can be performed, but the membrane is deteriorated in performance due to heat, chemical substances or pressure
Solution Approach 1:
The patent creates a composite membrane where an inorganic zeolite layer is formed on an organic porous support. The inorganic zeolite provides exceptional chemical resistance, oxidation resistance, heat resistant stability, and pressure resistance, while the organic support provides mechanical strength and flexibility.
Solution Approach 2:
The membrane structure is designed with different regions having different properties: the organic porous support provides mechanical strength and flexibility in regions requiring structural integrity, while the inorganic zeolite layer provides chemical and thermal resistance in regions exposed to harsh separation conditions.
3Manufacturing precision
If conventional separation methods are used, then separation can be achieved, but the applicable scope of objects intended to be separated is restrictive
Solution Approach 1:
The zeolite membrane with adjustable pore size (0.3-0.7 nm) can separate various straight-chain conjugated dienes (butadiene, piperylene, 1,3-hexadiene, etc.) from different mixtures including olefins, paraffins, and other hydrocarbons. By adjusting the pore size and zeolite composition, the same membrane system can be adapted to separate different target substances.
Solution Approach 2:
The patent achieves versatility by changing key parameters of the zeolite membrane including pore size (0.3-0.7 nm), Si/Al ratio (5-50), and cation type (Na+, K+, Cs+, Ca2+, Sr2+, Ba2+). These parameter adjustments allow the membrane to be optimized for separating different straight-chain conjugated dienes from various mixture compositions.
4Manufacturing precision
If zeolite membrane composite is used to separate straight-chain conjugated diene from olefin mixture, then high separation performance is achieved, but specific pore size and composition must be precisely controlled
Solution Approach 1:
The patent establishes specific parameter ranges for the zeolite membrane: pore size 0.3-0.7 nm, Si/Al ratio 5-50, and alkali metal content 1-20 wt%. These controlled parameters optimize the balance between separation coefficient and permeability while providing clear manufacturing guidelines that reduce complexity.
Solution Approach 2:
The patent specifies that the zeolite layer thickness should be 0.1-10 μm, which is sufficient to achieve high separation performance without excessive thickness that would reduce permeability. This optimized thickness range provides the necessary separation function while maintaining high flux.
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 efficient and high-purity separation of straight-chain conjugated dienes, such as butadiene, from mixtures with straight-chain olefins, demonstrating improved separation coefficients and permeability, making it industrially viable.
Implementation Method 1
Crystalline alumino-silicate generally termed as zeolite, has fine spaces of molecular sizes (nano-space) in one crystal and is referred to as 'molecular sieve'
Implementation Method 2
Zeolites with such peculiar higher-order structures, perform a shape-selective function (molecular sieve function)
Implementation Method 3
a zeolite membrane composite comprising a porous support and a zeolite layer containing an alkali metal allows selectively a straight-chain conjugated diene to permeate therethrough
Implementation Method 4
a porous support and a zeolite layer formed on the surface and in the fine pores of the support
Data Source
AI summary
The present invention provides a method for selectively separating a straight-chain conjugated diene with high purity from a mixture containing the straight-chain conjugated diene and at least one type of straight-chain olefin. The method involves separating the straight-chain conjugated diene from the mixture containing the straight-chain conjugated diene and the straight-chain olefin using a zeolite membrane composite. The composite contains a porous support and a zeolite layer formed on the surface and in the fine pores of the support, and the zeolite contains an alkali metal cation.