Group IIIB Modified Molecular Sieve for Heavy Metal Resistance
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Solution Overview
Problem
Current molecular sieves used in catalytic cracking of heavy oil lack sufficient activity stability and heavy metal contamination resistance, particularly due to the deposition of nickel and vanadium which degrade the catalyst's structure and activity.
Innovation Solution
A method for preparing a modified molecular sieve by controlling the particle size of Group IIIB element precipitates using a precipitating agent, organic complexing agent, and dispersing agent, which are deposited on the molecular sieve to enhance stability and contamination resistance, and a catalytic cracking catalyst containing this modified sieve.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If rare earths or phosphorus are used to modify the molecular sieve to improve activity and stability, then the catalytic activity and hydrothermal stability are improved, but the heavy metal contamination resistance is insufficient
Solution Approach 1:
The patent combines rare earth elements (for activity and stability) with Group IIIB element precipitates (for heavy metal resistance) to create a composite modified molecular sieve. This composite approach allows the catalyst to simultaneously achieve high catalytic activity, hydrothermal stability, and heavy metal contamination resistance by integrating the beneficial properties of different modifying agents.
Solution Approach 2:
The patent creates localized modifications on the molecular sieve surface by depositing Group IIIB element precipitates with controlled particle sizes (0.5-5 μm) at specific locations. This local quality approach ensures that heavy metal resistance is enhanced at critical sites where vanadium and nickel deposition occurs, while maintaining the overall structural integrity and catalytic properties of the molecular sieve.
2Object-affected harmful factors
If the molecular sieve is modified to enhance heavy metal resistance, then the contamination resistance is improved, but the activity stability may be compromised
Solution Approach 1:
The patent optimizes multiple parameters including the particle size of Group IIIB element precipitates (0.5-5 μm), the weight ratio of Group IIIB element oxide to molecular sieve (0.3-10:100), and the use of organic complexing agents and dispersing agents. These parameter changes ensure that the heavy metal resistance is enhanced without compromising the catalytic activity and hydrothermal stability of the molecular sieve.
3Object-affected harmful factors
If the particle size of Group IIIB element precipitates is reduced to improve dispersion, then the contamination resistance is enhanced, but the manufacturing complexity increases
Solution Approach 1:
The patent introduces organic complexing agents (such as citric acid, EDTA) and dispersing agents (such as cellulose derivatives, polyacrylamide) as intermediaries to control the precipitation and dispersion of Group IIIB elements. These intermediaries facilitate the formation of uniformly dispersed fine precipitates (0.5-5 μm) without requiring complex manufacturing equipment or multi-step processes, thereby enhancing heavy metal resistance while keeping the manufacturing process relatively simple.
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 modified molecular sieve exhibits improved activity stability and enhanced heavy metal contamination resistance, effectively capturing and stabilizing nickel and vanadium, leading to increased catalyst performance and longevity.
Implementation Method 1
mixing a molecular sieve slurry, a compound solution containing Group IIIB metal ion of the periodic table, an organic complexing agent and/or a dispersant and a precipitating agent to obtain a mixed slurry containing the precipitate of Group IIIB element of the periodic table
Implementation Method 2
a compound solution containing Group IIIB metal ion of the periodic table, an organic complexing agent and/or a dispersant
Implementation Method 3
an organic complexing agent and/or a dispersant
Data Source
AI summary
A preparation method for modified molecular sieve and a modified molecular sieve-containing catalytic cracking catalyst. The preparation method comprises: mixing molecular sieve slurry, a compound solution containing ions of group IIIB metals of the periodic table of elements, organic complexing agent and/or dispersing agent and precipitating agent to obtain mixed slurry containing molecular sieve and precipitates of group IIIB elements in the periodic table of elements; and drying, and roasting or not roasting to obtain molecular sieve modified by the group IIIB elements. A weight ratio of group IIIB elements calculated based on oxides to molecular sieve dry basis is equal to (0.3-10):100, a molar ratio of organic complexing agent to ions of group IIIB metals is equal to (0.3-10):1, and a molar ratio of dispersing agent to the ions of group IIIB metals is equal to (0.2-16):1. Also related to is the catalytic cracking catalyst containing the modified molecular sieve prepared according to the method. The molecular sieve prepared by the method or the catalytic cracking catalyst containing same has good activity stability and heavy metal pollution resistance.