Modified Y-type Zeolite Catalyst for LCO Cracking
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Solution Overview
Problem
Conventional catalytic cracking catalysts are inadequate for processing hydrogenated light cycle oil (LCO) due to poor cracking ability and high hydrogen transfer capacity, leading to inefficient production of light aromatics such as benzene, toluene, and xylene (BTX).
Innovation Solution
A modified Y-type molecular sieve with specific rare earth, phosphorus, gallium, and zirconium content is developed, combined with a catalytic cracking catalyst formulation that includes this molecular sieve, alumina binder, and clay, to enhance cracking activity and reduce hydrogen transfer reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalytic cracking catalysts are used to process hydrogenated LCO, then the catalyst has high hydrogen transfer capacity, but the cracking ability is poor and conversion efficiency is low
Solution Approach 1:
The patent modifies the molecular sieve by changing its chemical composition parameters - specifically incorporating rare earth elements (4-11% by weight), phosphorus (0.05-10% as P2O5), gallium (0.1-2.5% as Ga2O3), and zirconium (0.1-2.5% as ZrO2). These parameter changes transform the catalyst's properties to achieve both high cracking ability and appropriate hydrogen transfer capacity for processing hydrogenated LCO
Solution Approach 2:
The patent creates a composite molecular sieve material by combining multiple elements (rare earth, phosphorus, gallium, zirconium) within the Y-type molecular sieve structure. This composite approach allows the catalyst to simultaneously exhibit high cracking activity from the molecular sieve framework and controlled hydrogen transfer capacity from the metal modifications
2Reliability
If Y-type molecular sieve with small pore size (0.74 nm) is used, then the catalyst structure is stable, but the accessibility of active centers to polycyclic compounds is limited
Solution Approach 1:
The patent applies local quality modification by introducing secondary pores with larger pore sizes (2-10 nm) into specific regions of the molecular sieve structure. This creates localized access channels that allow polycyclic compounds to reach the active centers while the bulk molecular sieve framework maintains its structural stability and small pore size for shape selectivity
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 catalyst system demonstrates improved conversion efficiency of hydrogenated LCO, higher yield of BTX-rich gasoline, and lower coke selectivity, thereby optimizing the production of light aromatics.
Implementation Method 1
catalytic cracking catalyst, their preparation and application thereof
Data Source
AI summary
A modified Y-type molecular sieve has a rare earth content of about 4% to about 11% by weight on the basis of the oxide, a phosphorus content of about 0.05% to about 10% by weight on the basis of P2O5, a sodium content of no more than about 0.5% by weight on the basis of sodium oxide, a gallium content of about 0.1% to about 2.5% by weight on the basis of gallium oxide, and a zirconium content of about 0.1% to about 2.5% by weight on the basis of zirconia; and the modified Y-type molecular sieve has a total pore volume of about 0.36 mL/g to about 0.48 mL/g, a percentage of the pore volume of secondary pores having a pore size of 2-100 nm to the total pore volume of about 20% to about 40%.