Ethane-Rich Feed Separation With Hydrogen Slip for Ethylene Production

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Solution Overview

Problem

The separation of hydrogen and methane from ethane in naphtha-to-ethane-and-propane processes is costly due to the need for deep refrigeration or membrane and recycle compressors, which reduces the benefits of higher ethylene and propylene yields achieved by these processes.

Innovation Solution

A process and apparatus that separates a hydrocarbon feed into ethane-rich and propane-rich streams, allowing hydrogen and methane to slip into the ethane stream, reducing the need for expensive separation methods and optimizing the ethane stream for ethylene production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If deep refrigeration or membrane and recycle compressor is used to separate hydrogen and methane from ethane, then separation purity is improved, but equipment complexity and operating cost increase

Engineering Contradiction:

Improveseparation purityVSAvoidequipment complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary separation function by allowing hydrogen and methane to slip into the ethane stream rather than achieving complete separation. This removes the complex refrigeration or membrane systems while maintaining sufficient ethane purity for downstream cracking processes, where complete separation is not required.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent accepts a lower purity ethane stream containing hydrogen and methane slip, effectively using a 'good enough' separation approach rather than investing in expensive, complex separation equipment. The downstream cracking process tolerates this impurity level, making advanced separation unnecessary.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Manufacturing precision

If deep refrigeration or membrane and recycle compressor is used to separate hydrogen and methane from ethane, then separation purity is improved, but energy consumption increases

Engineering Contradiction:

Improveseparation purityVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent removes the energy-intensive separation step by allowing hydrogen and methane to remain in the ethane stream. The downstream cracking process can handle this composition without requiring pre-separation, thereby eliminating the high energy consumption associated with deep refrigeration or membrane compression.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent converts what would normally be considered a harmful impurity (hydrogen and methane in ethane stream) into an acceptable composition for downstream cracking. Rather than spending energy to remove these components, the process accepts them as part of the feed composition, turning a potential disadvantage into a workable solution.

Inventive Principle:

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

3Device complexity

If naphtha steam cracking is used to make ethylene and propylene, then process simplicity is maintained, but ethylene and propylene yields are reduced

Engineering Contradiction:

Improveprocess simplicityVSAvoidethylene and propylene yields

Core Design Contradiction:

Device complexityVSProductivity

Solution Approach 1:

The patent segments the cracking process into two distinct units: an ethane steam cracker and a propane dehydrogenation unit. This allows each unit to be optimized for its specific function, with the ethane cracker producing ethylene and the propane dehydrogenation unit producing propylene, thereby increasing overall yields while maintaining reasonable process complexity through modular design.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent creates a multi-functional processing system where the ethane stream from the NEP process serves dual purposes: it is fed to the ethane steam cracker for ethylene production and the composition is optimized to also support efficient propane dehydrogenation for propylene production, maximizing the utility of the feedstock processing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 reduces separation costs and energy consumption while maintaining high ethylene and propylene yields by minimizing the impact of hydrogen and methane on downstream processes, particularly in ethane steam cracking.

Implementation Method 1

separating the hydrocarbon feed comprising ethane, hydrogen, and/or methane and hydrocarbons with 3 or greater carbons into an ethane-rich stream comprising hydrocarbons with 2 or less carbons and a heavy stream comprising hydrocarbons with 3 or more carbons

Methodology Applied

Scientific EffectFractionation: Fractionation

Data Source

PatentUS12565459B2Naphtha to ethane and propane unit with hydrogen slip

Publication Date: 2026.03.03 UOP LLC

AI summary

A process for making ethylene from a hydrocarbon feed requires separating the hydrocarbon feed comprising ethane, hydrogen, and/or methane and hydrocarbons with 3 or greater carbons into an ethane-rich stream comprising hydrocarbons with 2 or less carbons and a heavy stream comprising hydrocarbons with 3 or more carbons. The ethane-rich stream is passed to a process which produces ethylene. The ethane-rich stream has an ethane to combined hydrogen and methane molar ratio of at least 1.2 and less than or equal to 10.