Oligomerization Zone Temperature Control for Diesel Yield
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Solution Overview
Problem
Existing processes for converting C4 and C5 olefins into diesel range products using oligomerization face challenges with catalyst deactivation due to coke formation, impurities, and contaminants, resulting in poor diesel quality and yield.
Innovation Solution
A process involving an oligomerization zone with a catalyst having a ten-membered ring pore structure, where the catalyst is partially deactivated by exposing it to contaminants or cyclo C5 hydrocarbons, and the peak bed temperature is gradually increased to maintain target product yields and cetane numbers, with regeneration of the catalyst as needed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the catalyst is used to convert C4 and C5 olefins into diesel range products, then the distillate yield is improved, but the catalyst becomes deactivated due to coke formation and contaminants
Solution Approach 1:
The patent applies preliminary action by intentionally deactivating the catalyst to a predetermined degree before operation using contaminants or cyclo C5 hydrocarbons. This pre-deactivation prevents excessive coke formation during operation, maintaining catalyst activity and extending operational cycles while achieving target distillate yields.
Solution Approach 2:
The patent implements periodic action through cyclic operation modes where the reactor alternates between production mode (achieving distillate yield) and regeneration mode (restoring catalyst activity). This periodic cycling maintains long-term catalyst reliability while maximizing productivity during production phases.
2Productivity
If the peak bed temperature is increased to counteract catalyst deactivation, then the distillate yield is improved, but byproduct production increases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the peak bed temperature within a specific range (200-250°C) and adjusting it dynamically based on catalyst deactivation level. This controlled temperature parameter change maintains distillate yield while minimizing byproduct formation compared to higher temperature operations.
Solution Approach 2:
The patent ensures continuity of useful action by maintaining the catalyst in a partially deactivated state that provides sustained activity for distillate production. This continuous controlled operation avoids the need for frequent shutdowns and regenerations, maintaining productivity while controlling byproduct formation through consistent temperature management.
3Speed
If the catalyst is fully active, then the reaction rate is high, but the catalyst deactivates rapidly due to coke formation
Solution Approach 1:
The patent applies preliminary action by pre-deactivating the catalyst to a controlled extent before operation. This creates an optimal balance where sufficient active sites remain for high reaction rates while the deactivated portions act as reservoirs that slowly release activity, extending catalyst operational life without sacrificing productivity.
Solution Approach 2:
The patent implements dynamics by allowing the catalyst activity to evolve dynamically during operation. The catalyst transitions from a partially deactivated initial state through controlled deactivation during production, then undergoes regeneration to restore activity. This dynamic management optimizes both reaction rate and operational duration throughout the catalyst lifecycle.
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 a target distillate yield of greater than 50 wt % and a cetane number of at least 35, while minimizing byproduct production and extending reactor operation cycles, despite catalyst deactivation.
Implementation Method 1
includes a catalyst with a ten-membered ring pore structure and is configured to selectively oligomerize the olefins
Implementation Method 2
deactivating the catalyst by coking, by exposing the catalyst to contaminants or including at least cyclo C5 hydrocarbons
Implementation Method 3
increasing the peak bed temperature of the oligomerization reaction zone in response to the deactivation of the catalyst
Implementation Method 4
regenerating the catalyst after the peak bed temperature of the oligomerization reaction zone has been increased
Data Source
AI summary
Processes for oligomerizing olefins to produce diesel. The oligomerization zone temperature is controlled to counteract catalyst deactivation caused by coking, by contaminants such as cyclo C5 and/or cyclo C6 hydrocarbons, or both. The temperature is increased in increments to ensure that that the oligomerization zone is producing product at a target product yield with a target product quality, which may be measured by a product cetane number. The target product yield is at least 50 wt % and a target product cetane number may be at least 35.