Mesoporous Pseudo-Boehmite for Heavy Oil Diffusion and Low Coke Yield
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Solution Overview
Problem
Conventional pseudo-boehmite used in catalytic cracking catalysts has low crystallinity and a most probable pore size of only 3.8 nm, hindering efficient diffusion and conversion of heavy oil molecules, leading to increased coke yield and reduced product distribution, and lacks wear resistance.
Innovation Solution
A method to prepare mesoporous pseudo-boehmite with a most probable pore size greater than 4.5 nm and rich in surface hydroxyl groups, achieved by reacting sodium aluminate with CO2, aging under controlled conditions, and adding a hydroxyl regulator like ammonia water or urea, followed by filtration and drying, to enhance bonding performance and wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pseudo-boehmite with small pore size (3.8 nm) is used, then the catalyst structure is stable, but the diffusion of heavy oil molecules is hindered and coke yield increases
Solution Approach 1:
The patent changes the pore size parameter of pseudo-boehmite from conventional 3.8 nm to 4.5-12 nm through controlled aging conditions (temperature, time, pH value), enabling better diffusion of heavy oil molecules while reducing coke formation
Solution Approach 2:
The patent performs preliminary aging treatment of pseudo-boehmite before catalyst formation to pre-establish the desired pore structure, ensuring that the pore size distribution is optimized before the catalyst is used for catalytic cracking
2Productivity
If pseudo-boehmite with larger pore size is prepared, then molecular diffusion is improved, but wear resistance deteriorates
Solution Approach 1:
The patent optimizes multiple parameters including aging temperature (100-185°C), aging time (2-11.5 hours), and pH value (8.5-10.5) to achieve a balance between pore size (4.5-12 nm) and crystallinity, resulting in both improved diffusion and maintained wear resistance
Solution Approach 2:
The patent creates a composite structure by controlling the formation of pseudo-boehmite with specific pore size distribution and crystallinity characteristics, combining the benefits of larger pores for diffusion with structural integrity for wear resistance
3Ease of manufacture
If conventional carbonization method is used, then production cost is reduced, but pore size distribution is limited and cannot provide larger mesopores
Solution Approach 1:
The patent modifies the carbonization process by controlling aging conditions (temperature, time, pH) to achieve precise control over pore size distribution (4.5-12 nm), maintaining the cost-effectiveness of carbonization while improving pore structure control
Solution Approach 2:
The patent performs preliminary aging treatment during the carbonization process to pre-determine the pore size distribution, enabling the conventional carbonization method to produce pseudo-boehmite with controlled larger mesopores
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 prepared mesoporous pseudo-boehmite forms a catalytic cracking catalyst with improved pore structure, enhancing molecular diffusion, reducing coke yield, and increasing the yield of high-value products while maintaining catalyst strength.
Implementation Method 1
reacting sodium aluminate with CO2
Implementation Method 2
aging under controlled conditions
Implementation Method 3
adding a hydroxyl regulator like ammonia water or urea
Data Source
AI summary
A mesoporous pseudo-boehmite rich in surface hydroxyl groups and a preparation method thereof are provided. A catalytic cracking catalyst contains the mesoporous pseudo-boehmite is prepared and used in catalytic reactions. The pseudo-boehmite has a most probable pore size greater than 4.5 nm and not more than 12 nm.