Molecular Sieve Crystallization via Supercritical High Throughput
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Solution Overview
Problem
The high cost and long crystallization time of synthetic molecular sieves limit their manufacturing efficiency, necessitating a high throughput process that reduces production costs and time while maintaining product quality.
Innovation Solution
A method involving a mixture with a solid content of 15-50 wt.% and crystallization at temperatures between 200°C to 500°C for less than 100 hours, using a source of tetravalent elements, hydroxide sources, and water, with stirring, to produce crystalline molecular sieves with pore sizes between 2-19 Å, and optionally using low directing agents and seed crystals to enhance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional crystallization methods are used to manufacture molecular sieves, then product quality is maintained, but production time is long and manufacturing cost is high
Solution Approach 1:
The patent applies parameter changes by modifying the crystallization temperature to supercritical conditions (above the critical temperature and pressure of water), which fundamentally alters the reaction kinetics and reduces crystallization time from days to hours while maintaining molecular sieve quality
Solution Approach 2:
The patent employs periodic action through controlled cycling of temperature and pressure conditions during crystallization, allowing the system to alternate between rapid nucleation and controlled growth phases, thereby achieving high throughput without sacrificing crystal quality
2Productivity
If conventional crystallization methods are used to manufacture molecular sieves, then product quality is maintained, but manufacturing cost increases
Solution Approach 1:
By changing to supercritical crystallization parameters, the patent eliminates the need for extended processing times and reduces energy consumption associated with prolonged heating, thereby lowering manufacturing costs while increasing throughput
Solution Approach 2:
The patent skips the conventional slow crystallization process by rushing through to supercritical conditions that enable rapid crystal formation, significantly reducing both time and cost while maintaining product quality
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 a high weight hourly throughput, reducing production time and costs, while producing molecular sieves with improved yield and quality, and allows for the reuse of directing agents, thereby lowering overall expenses.
Implementation Method 1
the synthesis mixture is subjected to appropriate crystallization conditions in an autoclave. Such conditions usually involve heating of the synthesis mixture to an elevated temperature
Implementation Method 2
this treatment also serves to decompose and/or oxidize the residue of the organic directing agent which may be occluded in the pores of the crystals
Implementation Method 3
Such a calcination treatment not only removes water from the crystals, but this treatment also serves to decompose and/or oxidize the residue
Data Source
AI summary
A method of crystallizing a crystalline molecular sieve having a pore size in the range of from about 2 to about 19 Å, said method comprising the steps of (a) providing a mixture comprising at least one source of ions of tetravalent element (Y), at least one hydroxide source (OH), and water, said mixture having a solid-content in the range of from about 15 wt. % to about 50 wt. %; and (b) treating said mixture to form the desired crystalline molecular sieve with stirring at crystallization conditions sufficient to obtain a weight hourly throughput from about 0.005 to about 1 hr−1, wherein said crystallization conditions comprise a temperature in the range of from about 200° C. to about 500° C. and a crystallization time less than 100 hr.