Ionic Liquid Catalyst for Ethylene Oligomerization
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Solution Overview
Problem
Current ethylene oligomerization processes are inefficient when using mixed hydrocarbon streams with low-purity ethylene, as conventional catalysts fail to achieve high conversion and selectivity for jet and diesel fuel range hydrocarbons, and are susceptible to poisoning by impurities.
Innovation Solution
An ethylene oligomerization process using an ionic liquid catalyst and co-catalyst to convert low-purity ethylene feeds into high molecular weight hydrocarbons, specifically producing C10-C55 hydrocarbons suitable for jet, diesel, and lubricating oil applications, with the ability to tolerate impurities and adjust product boiling ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional catalysts (zeolite or mineral acid) are used for ethylene oligomerization, then the process can operate with simple feed requirements, but the conversion and selectivity for jet and diesel range hydrocarbons are unacceptable
Solution Approach 1:
The patent changes the chemical parameters of the catalyst system by using ionic liquids with specific compositions (e.g., imidazolium, pyridinium, ammonium cations with various anions) and controlling reaction conditions (temperature 50-300°F, pressure 100-1000 psig) to achieve both high conversion/selectivity and tolerance to impurities
Solution Approach 2:
The patent employs composite catalyst systems combining ionic liquids with co-catalysts (such as aluminum halides, boron halides, or metal complexes) to enhance both the activity and selectivity for producing jet and diesel range hydrocarbons while maintaining impurity tolerance
2Productivity
If pure ethylene feed is used with conventional catalysts, then high conversion can be achieved, but expensive separation units and complex processing are required
Solution Approach 1:
The patent converts the harmful effect of impurities (which normally poison conventional catalysts) into a beneficial feature by using ionic liquid catalysts that are inherently tolerant to sulfur, nitrogen compounds, oxygenates, and other impurities, allowing direct use of mixed hydrocarbon streams without expensive purification
Solution Approach 2:
The ionic liquid catalyst system serves multiple functions simultaneously: it catalyzes oligomerization, tolerates various impurities without deactivation, and enables production of multiple product ranges (gasoline, jet, diesel) from a single feed stream, eliminating the need for separate purification and processing units
3Reliability
If ionic liquid catalysts are used to process mixed hydrocarbon streams, then impurity tolerance is improved, but achieving high diesel selectivity and conversion from low-purity ethylene feeds remains difficult
Solution Approach 1:
The patent optimizes reaction parameters including temperature (50-300°F range), pressure (100-1000 psig), and residence time to maximize both conversion and diesel-range selectivity while maintaining catalyst stability in the presence of impurities
Solution Approach 2:
The patent uses specific ionic liquid compositions with tailored cations (imidazolium, pyridinium, ammonium) and anions (halides, tetrafluoroborate, hexafluorophosphate, trifluoromethanesulfonate) to create localized active sites that favor oligomerization to diesel range products while resisting impurity poisoning
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 process achieves greater than 30% hydrocarbon yield by weight of ethylene feed, with over 45% of the product boiling in the jet and diesel range, and less than 2 mol% olefinic hydrogen content, effectively utilizing mixed hydrocarbon streams and improving fuel gas processing efficiency.
Implementation Method 1
ethylene oligomerization process using an ionic liquid catalyst and co-catalyst to convert low-purity ethylene feeds into high molecular weight hydrocarbons
Data Source
AI summary
Provided herein are processes for ethylene oligomerization in the presence of an ionic liquid catalyst and a co-catalyst to produce a hydrocarbon product comprising C10-C55 oligomers.