Zeolite Synthesis in Continuous Flow Reactors with Pulsatile Regime
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Solution Overview
Problem
Continuous flow reactors used in zeolitic material synthesis face issues with clogging due to drastic viscosity increases during crystallization, leading to inhomogeneous reaction conditions and prolonged reaction times, limiting the economic viability of zeolite production.
Innovation Solution
Implementing a pulsatile flow regime with a defined shear rate in continuous flow reactors during the synthesis of zeolitic materials to prevent clogging and enhance heat transfer, using a mixture of solvents, structure directing agents, and SiO2 sources, which are continuously fed and heated, with specific operational parameters to achieve optimal shear rates and homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If continuous flow reactors are used for zeolite synthesis, then productivity is improved, but clogging occurs due to drastic viscosity increases during crystallization
Solution Approach 1:
The patent applies periodic action by implementing a pulsatile flow regime in the continuous reactor. The flow alternates between high and low rates, creating periodic disturbances that prevent clogging during zeolite synthesis. This periodic variation in flow rate maintains mixing and prevents solid deposition while allowing continuous operation, thus resolving the contradiction between improved productivity and prevented clogging.
2Temperature
If laminar flow is used in tubular reactors, then heat transfer is limited, but inhomogeneous treatment of synthesis gel occurs
Solution Approach 1:
The patent applies mechanical vibration through the pulsatile flow regime, which creates periodic disturbances and mixing in the reaction mixture. This mechanical action enhances heat transfer and prevents temperature gradients, ensuring homogeneous treatment of the synthesis gel throughout the reactor, thus resolving the contradiction between heat transfer and homogeneity.
3Reliability
If batch synthesis is used, then reaction conditions can be maintained, but space-time-yield is low
Solution Approach 1:
The patent applies continuity of useful action by implementing a continuous flow reactor system that operates without interruption. The reactor maintains continuous flow and mixing, allowing reaction conditions to be sustained while achieving much higher space-time-yields compared to batch processes. This continuous operation eliminates the need to empty and refill reactors, thus resolving the contradiction between reliable condition control and improved productivity.
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 pulsatile flow regime effectively prevents clogging and ensures uniform treatment of the synthesis gel, significantly reducing reaction times and improving the efficiency of zeolite production, allowing for more economically viable and efficient zeolite synthesis.
Implementation Method 1
a pulsatile flow regime is used in a continuous reactor geometry. In view thereof, reactor geometries have been conceived which allow for a rapid synthesis of zeolitic materials.
Implementation Method 2
the core will show almost no shear rate due to the slow rate of heat transfer towards the core
Implementation Method 3
the synthesis gel will typically show high shear rates in the region near the wall, whereas the core will show almost no shear rate due to the slow rate of heat transfer towards the core
Data Source
AI summary
The present invention relates to a continuous process for the preparation of a zeolitic material comprising SiO2 in its framework structure, said process comprising (i) continuously preparing a mixture comprising one or more solvents, one or more structure directing agents, and one or more sources of SiO2; (ii) continuously feeding the mixture prepared in (i) into one or more continuous flow reactors; and (iii) heating the mixture in the one or more continuous flow reactors for continuously obtaining a zeolitic material comprising SiO2 in its framework structure; wherein the mixture contained in the one or more continuous flow reactors is subject to a pulsatile flow regime. The present invention also relates to a zeolitic material as obtainable and/or obtained according to said process and the use of the zeolite material as a molecular sieve, as an adsorbent, for ion-exchange, or as a catalyst and/or as a catalyst support.