Zeolite Adsorbent Nitrile Removal Oligomerization Feed
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Solution Overview
Problem
Current processes for removing nitriles from hydrocarbon feeds in higher olefins oligomerization are inefficient, as they either partially remove nitriles, generate waste, or require costly regeneration of adsorbents, leading to catalyst deactivation and economic challenges.
Innovation Solution
A continuous process utilizing two adsorbers with zeolites of faujasite structure, where the hydrocarbon feed is switched between them for nitrile adsorption and desorption using the hydrocarbon product as a desorbing solvent, eliminating the need for additional solvents and waste streams.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If commercial guard beds are used to adsorb nitriles from feedstreams, then nitrile removal is achieved, but the guard bed capacity is too low to achieve commercial run lengths
Solution Approach 1:
The patent changes the chemical and physical parameters of the adsorbent by using zeolite with faujasite structure instead of conventional alumina guard beds. This zeolite adsorbent has higher nitrile uptake capacity and maintains stable performance over extended periods, achieving commercial run lengths while effectively removing nitriles from the feedstream.
Solution Approach 2:
The patent employs a composite approach by combining the adsorbent function with a specific zeolite structure that has both high nitrile affinity and long-term stability. The zeolite material integrates multiple desirable properties: high capacity for nitrile adsorption, resistance to deactivation, and suitability for continuous operation in oligomerization processes.
2Reliability
If guard bed is regenerated by heating under nitrogen or hydrocarbon flow, then full desorption is achieved, but additional apparatus and nitrogen/hydrocarbon supply are required
Solution Approach 1:
The patent implements self-service regeneration by using a portion of the hydrocarbon product stream from the oligomerization reactor to desorb nitriles from the spent zeolite adsorbent. This eliminates the need for separate regeneration apparatus and external nitrogen or hydrocarbon supplies, as the process uses its own product stream for adsorbent regeneration.
Solution Approach 2:
The hydrocarbon product stream serves multiple functions: it is both the desired product of the oligomerization process and the desorbing agent for regenerating the adsorbent. This multi-functionality simplifies the overall process by eliminating dedicated regeneration systems and reducing equipment complexity.
3Quantity of substance
If water washing is used to remove nitriles from olefin feeds, then partial removal is achieved, but a lot of waste water is generated
Solution Approach 1:
The patent extracts nitriles from the olefin feedstream through adsorption onto zeolite, completely removing the harmful impurity rather than partially removing it as in water washing. The nitriles are taken out of the system and concentrated on the adsorbent, which is then regenerated, eliminating the need for large volumes of waste water generation.
Solution Approach 2:
Instead of using large amounts of water that become waste, the patent uses a small amount of hydrocarbon product as a recyclable desorbing agent. The desorbent is regenerated and reused in the process, avoiding the creation of disposable waste streams.
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 process effectively reduces nitrile content in hydrocarbon feeds, prolongs catalyst life, and integrates nitrile removal into the oligomerization process without generating waste or requiring extra desorbing solvents, achieving longer adsorbent lifetimes and improved operational efficiency.
Implementation Method 1
contacting a hydrocarbon feed comprising nitriles with at least one adsorbent comprising a zeolite with a faujasite structure in order to remove nitriles from the feed
Implementation Method 2
desorbing the nitriles adsorbed on the at least one adsorbent of the first adsorber with a portion of the hydrocarbon product obtained in step ii)
Data Source
AI summary
In a feed clean-up process at least two adsorbents (2, 4)are installed in front of an oligomerization reactor(3). Olefin feed is sent over one adsorbent (2) and the nitrile poisons are adsorbed so that clean feed will enter the reactor (3). Before the adsorbent (2)will be saturated, the feed (1) is sent to the other, fresh adsorbent (4). At the same time oligomerization product from the reactor (3) is used to desorb nitriles from the spent adsorbent (2).