Fluid Catalytic Cracking Oligomerate Process for Propylene Yield
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Solution Overview
Problem
Current catalysts for oligomerizing light olefins struggle to produce high yields of high-quality gasoline and diesel efficiently, as they often result in undesirable products due to branching and boiling point issues, and are limited in cracking heavier olefins to propylene.
Innovation Solution
The process involves an oligomerization system with a fluid catalytic cracking (FCC) zone, purification, and oligomerization zones, using specific catalysts and recycling techniques to optimize the production of propylene by cracking distillate to propylene and controlling branching and boiling points, with C5 olefins added to the feed to reduce further oligomerization and increase gasoline yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If catalysts are used to make high octane gasoline through oligomerization, then octane value is improved, but the product becomes highly branched and falls within gasoline boiling point range which is undesirable for diesel
Solution Approach 1:
The patent changes the oligomerization parameters by using specific catalysts (zeolites with different pore structures like MTT, MTW, MFI) and controlling reaction conditions (temperature, pressure, space velocity) to produce oligomers with controlled branching. This allows the same process to produce either high-octane gasoline (with branching) or high-cetane diesel (with more linear structures) by adjusting parameters.
Solution Approach 2:
The patent segments the oligomerization process into different reaction zones or uses multiple catalysts with different selectivities to produce different product distributions. By separating the oligomerization into stages or using catalyst combinations, it can produce both gasoline-range and diesel-range oligomers with desired properties.
2Manufacturing precision
If catalysts are used to make high cetane diesel through oligomerization, then cetane rating is improved, but the product becomes more linear and falls in distillate boiling point range which results in less and poorer quality gasoline
Solution Approach 1:
By changing catalyst type (from high-acidity zeolites for gasoline to lower-acidity or different-pore-size zeolites for diesel) and adjusting reaction parameters (temperature, pressure, olefin feed composition), the process can shift product distribution between gasoline and diesel ranges while maintaining desired quality metrics.
Solution Approach 2:
The patent employs dynamic control of reaction conditions and catalyst selection to adapt product distribution to market demands. The system can be adjusted in real-time to produce more gasoline or more diesel based on required cetane ratings and octane values, making the process flexible rather than fixed.
3Productivity
If heavy oligomers are produced by oligomerization to maximize propylene from FCC, then propylene production is improved, but some heavy oligomers are resistant to cracking down to propylene
Solution Approach 1:
The patent controls oligomerization parameters (catalyst acidity, temperature, pressure, residence time) to produce heavy oligomers with specific structural characteristics that are more amenable to cracking. By adjusting these parameters, the oligomers are designed to crack efficiently to propylene in the FCC unit rather than resisting cracking.
Solution Approach 2:
The system uses feedback from the FCC unit performance to adjust oligomerization conditions. By monitoring propylene yield and cracking efficiency, the oligomerization process can be tuned to produce heavy oligomers that optimize propylene production while ensuring they crack efficiently in the FCC unit.
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 enhances the yield of high-quality gasoline and diesel by effectively cracking distillate to propylene, improving the octane value and cetane rating, and maximizing gasoline and diesel production while minimizing heavier olefin formation.
Implementation Method 1
fluid catalytic cracking (FCC) zone
Implementation Method 2
oligomerization zones, using specific catalysts
Implementation Method 3
hydrogenating some of the heavy olefinic product
Data Source
AI summary
Distillate cracks to propylene more readily than VGO. Additionally, less branched hydrocarbons crack to propylene more readily than more branched hydrocarbons. Oligomerization to diesel range oligomers followed by catalytic cracking with less branched oligomers can provide more propylene.