Attrition Resistant Molecular Sieve Catalyst via Rotor-Stator Mixing
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Solution Overview
Problem
Existing molecular sieve catalysts lack sufficient attrition resistance, leading to premature breakdown in commercial-scale processes, which limits their effective lifespan and efficiency.
Innovation Solution
A method involving the creation of a high solids content, low viscosity slurry using a rotor-stator mixer, followed by spray drying and calcination, to produce a molecular sieve catalyst with enhanced attrition resistance, utilizing metalloaluminophosphate molecular sieve crystals, clay, and a binder, specifically designed for commercial-scale manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mixing methods are used to prepare molecular sieve catalyst, then the manufacturing process is simple, but the catalyst lacks sufficient attrition resistance
Solution Approach 1:
The patent changes the mixing parameters by using a rotor-stator mixer with specific gap distances (0.05-0.5 mm) and rotation speeds (1000-10000 rpm), along with controlling slurry viscosity (10-10000 cP) and solids content (30-70 wt%), to achieve high attrition resistance without overly complicating the process
Solution Approach 2:
The patent introduces a binder as an intermediary material that coats the molecular sieve crystals, forming a protective layer that enhances attrition resistance. The binder acts as a mediator between the crystal surfaces, preventing direct contact and fragmentation under stress
2Reliability
If high solids content slurry is used, then attrition resistance improves, but slurry viscosity increases making mixing difficult
Solution Approach 1:
The patent employs dynamic mixing conditions by using a rotor-stator system with variable rotation speeds and adjustable gap distances, allowing the mixing intensity to adapt to the changing slurry viscosity as solids content increases, maintaining mixing effectiveness throughout the process
Solution Approach 2:
The high-speed rotation of the rotor (1000-10000 rpm) creates mechanical vibration and shear forces that prevent particle aggregation in high solids content slurries, reducing effective viscosity and improving mixability despite high solid loading
3Ease of manufacture
If rotor-stator mixer with small gap is used, then slurry viscosity decreases improving mixability, but manufacturing precision requirements increase
Solution Approach 1:
The patent provides a range of acceptable gap distances (0.05-0.5 mm) rather than a single precise value, allowing manufacturers to select appropriate precision levels based on equipment capabilities while still achieving the desired viscosity reduction and mixing effectiveness
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 resulting catalyst exhibits improved attrition resistance, measured by a low attrition rate index, allowing for increased durability and extended lifespan in reaction processes, such as olefin production, while maintaining operational efficiency.
Implementation Method 1
The rotor and stator have a gap distance of not greater than 0.3 mm... the rotor is rotated at a tip speed of at least 5 m/sec
Implementation Method 2
drying the slurry to form the finished catalyst... spray drying
Implementation Method 3
Following spray drying, the catalyst material is calcined to form a finished catalyst product
Data Source
AI summary
This invention provides a process for making an attrition resistant molecular sieve catalyst composition. The formation of highly attrition resistant catalyst particles is accomplished by initially mixing together catalyst components to form a slurry at a relatively low viscosity and high solids content. Preferably, a slurry having characteristics of high solids content and low viscosity is achieved using a rotor-stator mixer. Once the desired slurry characteristics are obtained, the slurry is dried, preferably by spray drying and calcining, to form a highly attrition resistant catalyst.