Low-Acidity FCC Catalyst for Low-Aromatic Middle Distillates
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Solution Overview
Problem
Conventional fluid catalytic cracking (FCC) processes face challenges in maximizing the production of high-value derivatives like gasoline and LPG while minimizing the production of coke and fuel gas, which affects catalyst circulation rates and operational efficiency, and struggle to produce middle distillates with low aromaticity without compromising reaction temperatures or increasing residual fractions.
Innovation Solution
A dense-bed reactor process using catalysts of low activity and basic character, with extended contact times and high catalyst/oil mass ratios, operates within conventional FCC temperatures to produce middle distillates with low aromaticity, avoiding the issues associated with low-severity operations and promoting the formation of saturated hydrocarbons.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional FCC processes operate with short contact times (1-4 seconds) and high catalyst activity to maximize gasoline and LPG production, then conversion efficiency improves, but aromaticity in middle distillates increases and selectivity deteriorates
Solution Approach 1:
The patent applies parameter changes by extending the catalyst-contact time from conventional 1-4 seconds to 30 seconds or more, and by using catalysts with low activity and basic character instead of conventional high-acidity catalysts. These parameter changes transform the reaction mechanism to reduce aromatic formation while maintaining acceptable conversion rates, directly resolving the contradiction between productivity and manufacturing precision.
2Quantity of substance
If FCC processes use high catalyst activity and short contact times to maximize light hydrocarbon yield, then gasoline and LPG production increases, but middle distillate quality deteriorates due to high aromatic content
Solution Approach 1:
The patent changes the contact time parameter to 30 seconds or more and uses basic character catalysts with low activity, which fundamentally alters the reaction pathway. This produces middle distillates with low aromaticity suitable for diesel pools while still achieving acceptable conversion of heavy feeds, resolving the contradiction between quantity of light hydrocarbons and quality of middle distillates.
3Manufacturing precision
If low-severity FCC operations are used to reduce aromaticity in middle distillates, then aromatic content decreases, but reaction temperatures must be lowered which increases residual fractions
Solution Approach 1:
Instead of lowering temperature to reduce aromaticity, the patent uses a different parameter: extending contact time to 30 seconds or more and employing basic character catalysts. This allows operation at conventional temperatures while achieving low aromaticity in middle distillates and acceptable conversion rates, avoiding the problem of increased residual fractions.
4Productivity
If conventional high-acidity catalysts are used for maximum conversion, then productivity improves, but aromatic hydrocarbon formation increases
Solution Approach 1:
The patent changes the catalyst property parameter from high acidity to basic character and extends contact time to 30 seconds or more. This transformation reduces aromatic hydrocarbon formation through a different reaction mechanism while maintaining acceptable conversion rates, directly addressing the harmful effect of aromatic formation.
5Manufacturing precision
If extended contact times (30 seconds or more) are used with low-activity basic catalysts to reduce aromaticity, then middle distillate quality improves, but conversion efficiency may decrease
Solution Approach 1:
The patent uses parameter changes (extended contact time and basic catalysts) to achieve a new operational balance. While contact time increases to 30 seconds or more, the basic character catalysts maintain adequate conversion activity, producing middle distillates suitable for diesel pools with low aromaticity and acceptable conversion rates simultaneously.
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 achieves high conversion levels and significantly reduces aromatic hydrocarbon production, resulting in middle distillates suitable for diesel pools and petrochemical naphtha, while maintaining efficient catalyst rectification and avoiding the drawbacks of low-temperature operations.
Implementation Method 1
contacting the feed with a cracking catalyst for a time of at least 30 seconds
Implementation Method 2
using catalysts of low activity and basic character
Implementation Method 3
dense-bed reactor process using catalysts of low activity and basic character, with extended contact times
Implementation Method 4
maintaining efficient catalyst rectification
Data Source
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AI summary
The present invention relates to a process and equipment for fluid catalytic cracking for the production of middle distillates of low aromaticity that comprises cracking a mixed feed consisting of heavy fractions of hydrocarbons, in the absence of added hydrogen, employing a catalyst of low activity and low acidity and contacting the feed for at least 30 seconds, in a dense-bed FCC reactor to produce an effluent constituted of fractions of middle distillates and naphtha of low aromaticity.