Nano-sized Mesoporous Beta Zeolite Synthesis for Hydrocracking
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Solution Overview
Problem
Conventional beta zeolites have small pore sizes that restrict the diffusion of large molecules in heavy oil fractions, limiting their catalytic performance in hydrocracking processes due to intrinsic pore dimension and accessibility limitations.
Innovation Solution
The synthesis of nano-sized mesoporous beta zeolites with pore sizes between 2 and 60 nanometers and particle sizes less than 100 nanometers, achieved through methods involving the formation of an aluminosilicate fluid gel, hydrothermal treatment, and templating with cetyltrimethylammonium bromide, which eliminates the need for ion exchange steps and introduces ordered mesoporosity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional beta zeolites are used, then the catalytic activity is maintained at acceptable levels, but the pore sizes are too small to allow effective diffusion of large molecules in heavy oil fractions
Solution Approach 1:
The patent changes the pore size parameter from conventional small pores to mesoporous structures with controlled pore diameters (2-50 nm), enabling better diffusion of heavy oil molecules while maintaining catalytic activity through optimized pore architecture and surface area
Solution Approach 2:
The invention creates mesoporous beta zeolites with ordered pore structures that provide enhanced mass transfer pathways for large molecules, combining the catalytic properties of zeolites with the diffusion benefits of mesoporous materials
2Productivity
If the particle size of zeolites is reduced to enhance mass transfer, then the external surface area increases, but the diffusion paths become shorter which may compromise structural stability
Solution Approach 1:
The patent optimizes particle size parameters to nanoscale dimensions (50-200 nm) where the high surface area to volume ratio enhances mass transfer while the nanoscale structure maintains sufficient structural integrity and stability during catalytic reactions
Solution Approach 2:
The invention creates composite mesoporous beta zeolite structures that combine the stability of crystalline zeolite frameworks with the high surface area benefits of nanoscale particles, achieving both structural stability and enhanced mass transfer
3Productivity
If ion exchange steps are used to produce proton form zeolites, then the catalytic activity is enhanced, but the process complexity and time requirements increase
Solution Approach 1:
The patent extracts and eliminates the ion exchange step from the conventional synthesis process, achieving proton form zeolites directly through controlled hydrothermal treatment and template removal, thereby simplifying the overall process while maintaining catalytic activity
Solution Approach 2:
The invention skips the traditional ion exchange intermediate step by directly forming the proton form zeolite through optimized hydrothermal synthesis conditions, reducing process time and complexity while achieving the desired catalytic properties
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 approach enhances mass transfer and catalytic performance by increasing the external surface area and reducing diffusion paths, leading to improved conversion of heavy oil fractions into lighter hydrocarbons, as demonstrated by increased yields and activity in hydrocracking reactions.
Implementation Method 1
the dried gel mixture is subject to hydrothermal treatment to produce a zeolite precursor
Implementation Method 2
cetyltrimethylammonium bromide (CTAB) is added to the zeolite precursor under alkaline conditions to form a templated mixture, and the templated mixture is subject to hydrothermal treatment to prepare a CTAB-templated zeolite
Implementation Method 3
The CTAB-templated zeolites are then subject to additional drying and calcination to produce a nano-sized mesoporous beta zeolite in a proton form
Implementation Method 4
contacting the hydrocarbon feedstock with a catalyst containing a nano-sized mesoporous beta zeolite under reaction conditions to produce a product stream containing at least 20 weight percent of hydrocarbons with one to four carbon atoms
Data Source
AI summary
Provided here are nano-sized mesoporous zeolite compositions and the methods of synthesis and use of these compositions. These nano-sized mesoporous zeolite compositions are synthesized from a mixture of silicon source and an aluminum source fumed or colloidal silica with aluminum powder or aluminum oxide. Also provided are methods for hydrocracking a hydrocarbon feedstock by using catalysts containing the nano-sized mesoporous zeolite composition.