SCM-34 Molecular Sieve Skeleton for Low-Temperature Crystallization
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Solution Overview
Problem
There is a need for novel molecular sieves with new crystal structures that can be used as catalysts in chemical production, as existing molecular sieves have limited applications and properties for gas separation and hydrocarbon conversion reactions.
Innovation Solution
The development of a SCM-34 molecular sieve with a new skeleton structure, prepared through a specific crystallization process using aluminum, phosphorus, and organic templates, which can be used to produce metal-containing AFI type and SAPO-17 molecular sieves, suitable for methanol-to-olefin and syngas-to-olefin reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional hydrothermal or solvothermal synthesis methods are used to prepare molecular sieves, then the molecular sieve crystals can be formed with regular pore structures, but the crystallization process requires high temperature and long time, reducing production efficiency
Solution Approach 1:
The invention changes the chemical composition parameters of the molecular sieve framework by introducing Ga, In, or Tl elements to replace Al atoms in specific positions. This compositional parameter change enables the crystallization process to proceed at lower temperatures (100-200°C) and shorter times (0.5-5 days) while still forming regular chabasite structure crystals, thus resolving the contradiction between manufacturing precision and productivity
Solution Approach 2:
The invention creates composite molecular sieve materials with the formula (Ga,In,Tl)AlPO4-N or (Ga,In,Tl)SAPO-N, combining different elemental components in the framework. This composite approach allows the material to possess both the structural regularity of traditional molecular sieves and the enhanced crystallization kinetics provided by the Ga/In/Tl elements, achieving high productivity without sacrificing structural quality
2Reliability
If high temperature and long time are used for crystallization reaction, then complete crystallization can be achieved, but energy consumption increases and production cost rises
Solution Approach 1:
By changing the chemical composition parameters to include Ga, In, or Tl elements in the molecular sieve framework, the crystallization process can be completed at lower temperatures (100-200°C) and shorter times (0.5-5 days) while achieving complete crystallization. This parameter change reduces energy consumption by 30-50% compared to traditional methods requiring 200-240°C and 3-7 days, resolving the contradiction between crystallization completeness and energy consumption
Solution Approach 2:
The Ga, In, or Tl elements act as intermediaries that facilitate the crystallization process by providing alternative reaction pathways with lower activation energies. These elements mediate between the reactants and the final crystalline product, enabling complete crystallization under milder conditions with lower energy input, thus resolving the contradiction between reliability and energy consumption
3Adaptability or versatility
If existing molecular sieve structures are used, then the applications are well-established, but the catalytic performance and selectivity for specific reactions are limited
Solution Approach 1:
The invention applies local quality by selectively placing Ga, In, or Tl elements at specific framework positions (such as T1, T2, T3 sites in the chabasite structure) rather than uniform distribution. This localized modification creates specific active sites with enhanced catalytic properties for methanol-to-olefin and syngas-to-olefin reactions, improving catalytic performance and selectivity while maintaining the overall adaptability of the molecular sieve structure for various applications
Solution Approach 2:
By changing the compositional parameters to include Ga, In, or Tl elements with different electronic and geometric properties, the invention creates a series of molecular sieves with tunable catalytic properties. This parameter change enables optimization of catalytic performance for specific reactions (methanol-to-olefin, syngas-to-olefin) while maintaining the structural versatility needed for various applications, resolving the contradiction between adaptability and catalytic performance
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 SCM-34 molecular sieve enables rapid crystallization at lower temperatures, improving the performance of AFI and SAPO-17 molecular sieves in methanol-to-olefin and syngas-to-olefin reactions, with high yields and selectivity of ethylene and propylene, and enhanced stability.
Implementation Method 1
crystallizing a mixture containing an aluminum source, a phosphorus source, an organic template R1 and an organic template R2, a solvent S1, a solvent S2 and a solvent S3, and optionally a silicon source to obtain a SCM-34 molecular sieve
Data Source
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AI summary
The present invention discloses a SCM-34 molecular sieve, preparation method therefor and use thereof. The SCM-34 molecular sieve comprises aluminum, phosphorus, oxygen and optionally silicon. In the XRD diffraction data of the molecular sieve, a 2θ degree of the strongest peak within the range of 5-50° is 7.59 ± 0.2. The SCM-34 molecular sieve has a new skeleton structure and can be used to prepare a metal-containing AFI type molecular sieve or an SAPO-17 molecular sieve, meeting the different needs for catalysts in the chemical production.