CO2 Recycle Stream Separation for Non-Cryogenic NGL Recovery

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Solution Overview

Problem

Current carbon dioxide reinjection processes for recovering natural gas liquids (NGLs) face inefficiencies due to high energy requirements and the need for cryogenic conditions, membranes, and carbon dioxide recovery solvents, which increase costs and complexity.

Innovation Solution

A method and system for recovering NGLs from a carbon dioxide recycle stream without subjecting it to cryogenic conditions, membranes, or carbon dioxide recovery solvents, involving a separator to split the stream into purified carbon dioxide and NGL streams, optimizing energy use and equipment requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cryogenic conditions, membranes, and carbon dioxide recovery solvents are used to separate NGLs from carbon dioxide recycle stream, then separation effectiveness is improved, but energy consumption increases and process complexity increases

Engineering Contradiction:

Improveseparation effectivenessVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters from extreme cryogenic temperatures to moderate temperatures, and from high pressure to atmospheric or near-atmospheric pressure. This allows the use of simple flash separation based on natural vapor pressure differences, eliminating the need for energy-intensive cryogenic cooling while achieving effective separation of NGLs from carbon dioxide

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts and removes the complex separation technologies (membranes, solvents, cryogenic systems) from the process, replacing them with a simple flash separation approach. This extraction of unnecessary complexity directly reduces energy consumption while maintaining separation effectiveness

Inventive Principle:

Principle #2Taking out (Extraction)

2Manufacturing precision

Engineering Contradiction:

Improveseparation effectivenessVSAvoidprocess complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent removes complex equipment such as cryogenic coolers, membrane separation units, and solvent recovery systems from the process flow. By extracting these unnecessary components and replacing them with a simple flash separation vessel, the process complexity is dramatically reduced while maintaining effective NGL recovery

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent segments the separation process into a simple two-phase flash separation (vapor and liquid phases), eliminating the need for complex multi-stage separation systems. This segmentation into basic physical phases simplifies the overall process design and operation

Inventive Principle:

Principle #1Segmentation

3Productivity

If conventional separation methods are used to recover NGLs from carbon dioxide recycle stream, then NGL recovery rate is improved, but energy expenditure increases

Engineering Contradiction:

ImproveNGL recovery rateVSAvoidenergy expenditure

Core Design Contradiction:

ProductivityVSUse of energy by stationary object

Solution Approach 1:

The patent allows the NGLs to self-separate from the carbon dioxide stream by utilizing their natural higher vapor pressure characteristics. The flash separation vessel enables this self-service separation without external energy input, as the lighter NGL components naturally vaporize and separate from the liquid phase, achieving high recovery rates with minimal energy expenditure

Inventive Principle:

Principle #25Self-service

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 energy consumption and simplifies the process, enabling more efficient NGL recovery with lower operational costs and improved process economics by balancing NGL recovery rates with energy expenditure.

Implementation Method 1

The separator is coupled to the piping and is configured to separate the recycle stream into a purified recycle stream and a natural gas liquids stream

Methodology Applied

Scientific EffectPhase separation: Two-Phase Flow

Data Source

PatentUS9574823B2Carbon dioxide recycle process

Publication Date: 2017.02.21 PILOT INTELLECTUAL PROPERTY LLC

AI summary

A method for recovering natural gas liquids without using cryogenic conditions, membranes, and carbon dioxide recovery solvents is provided. In one embodiment, a carbon dioxide recycle stream that comprises carbon dioxide and natural gas liquids is received. The carbon dioxide recycle stream is separated into a purified carbon dioxide recycle stream and a natural gas liquids stream. The purified carbon dioxide recycle stream comprises the carbon dioxide, and the natural gas liquids stream comprises the natural gas liquids. The carbon dioxide recycle stream, the purified carbon dioxide recycle stream, and the natural gas liquids are not subjected to cryogenic conditions, membranes, and carbon dioxide recovery solvents between being received and being separated into the purified carbon dioxide recycle stream and the natural gas liquids stream.