Zeolite Catalyst Oligomerization of Dilute Ethylene

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Solution Overview

Problem

The high cost associated with purifying ethylene streams for oligomerization due to the presence of impurities like hydrogen sulfide and mercaptans in fluid catalytic cracking (FCC) off-gas streams, which requires complex and costly purification processes, making the production of polymer-grade ethylene inefficient.

Innovation Solution

The use of a zeolite catalyst with 10-member rings for oligomerizing dilute ethylene feeds from FCC off-gas streams, followed by hydroprocessing to remove impurities and produce lubricant base oils and diesel fuel fractions, thereby reducing the need for extensive purification and lowering production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If complex purification schemes are used to remove impurities like hydrogen sulfide and mercaptans from FCC off-gas streams, then the quality of ethylene for oligomerization is improved, but the production cost and process complexity increase significantly

Engineering Contradiction:

Improveethylene purityVSAvoidpurification process complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies this principle by using the sulfur-containing impurities (hydrogen sulfide and mercaptans) present in FCC off-gas as a promoter for the oligomerization catalyst rather than removing them through complex purification. The sulfur compounds enhance catalyst activity and selectivity for producing lubricant-range oligomers, converting a traditionally harmful impurity into a beneficial additive that simplifies the process while improving product quality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

2Manufacturing precision

Engineering Contradiction:

Improveethylene purityVSAvoidproduction cost

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent eliminates costly purification steps by converting the harmful sulfur impurities into beneficial catalyst promoters. The hydrogen sulfide and mercaptans in the FCC off-gas enhance catalyst performance for oligomerization, allowing direct use of crude gas streams and significantly reducing production costs while maintaining product quality

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If traditional oligomerization catalysts are used with dilute ethylene feeds from FCC off-gas, then catalyst sensitivity to impurities causes poor performance, but replacing with impurity-resistant catalysts requires specific catalyst formulations

Engineering Contradiction:

Improvecatalyst performanceVSAvoidcatalyst formulation requirements

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies this principle by changing the chemical composition parameters of the catalyst formulation to include sulfur-tolerant components. The catalyst is specifically formulated with metals and supports that maintain high activity and selectivity in the presence of sulfur-containing impurities, enabling reliable performance with crude FCC off-gas feeds without requiring pre-purification

Inventive Principle:

Principle #35Parameter changes

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 method allows for the efficient production of lubricant base oils and diesel fuels from impure ethylene streams, reducing production costs by utilizing a zeolite catalyst to tolerate impurities and subsequent hydroprocessing to improve product properties, thus overcoming the inefficiencies of traditional purification methods.

Implementation Method 1

The use of a zeolite catalyst with 10-member rings for oligomerizing dilute ethylene feeds from FCC off-gas streams

Methodology Applied

Scientific EffectOligomerization: Chemical Bonding

Implementation Method 2

hydroprocessing at least a portion of the oligomerized effluent under effective hydroprocessing conditions to form a hydroprocessed effluent, wherein hydroprocessing at least a portion of the oligomerized effluent comprises hydrotreating

Methodology Applied

Scientific EffectHydrotreating: Hydrogenation

Data Source

PatentEP2970043B1Production of lubricant base oils from dilute ethylene feeds

Publication Date: 2019.10.09 EXXONMOBIL TECHNOLOGY & ENGINEERING CO

Figure 1

AI summary

Methods are provided for oligomerizing a dilute ethylene feed to form oligomers suitable for use as fuels and/or lubricant base oils. The fuels and/or lubricant base oils are formed by oligomerization of impure dilute ethylene with a zeolitic catalyst, where the zeolitic catalyst is resistant to the presence of poisons such as sulfur and nitrogen in the ethylene feed. The oligomers can also be formed in presence of diluents such as light paraffins.