CO₂ Recycle Stream Dehydration with Ethylene Glycol for NGL Recovery

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Solution Overview

Problem

Existing carbon dioxide reinjection processes for enhanced oil recovery struggle with inefficient recovery of natural gas liquids (NGLs) and high energy consumption, necessitating a more optimized method to enhance NGL recovery rates while minimizing energy expenditure.

Innovation Solution

A method and system for optimizing NGL recovery by separating a carbon dioxide recycle stream into a purified carbon dioxide stream and a natural gas liquids stream using a separator, followed by a dehydrating process and controlled energy usage in compressors, resulting in a high-quality NGL rich stream with reduced energy requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional carbon dioxide reinjection processes are used for enhanced oil recovery, then oil extraction is achieved, but natural gas liquids recovery is inefficient and energy consumption is high

Engineering Contradiction:

ImproveNGL recovery rateVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent segments the carbon dioxide recycle stream into multiple components using a separator: purified carbon dioxide stream, natural gas liquids stream, and water stream. This segmentation allows targeted recovery of NGLs without processing the entire stream through high-energy equipment, thereby improving NGL recovery efficiency while reducing overall energy consumption.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extracts natural gas liquids from the carbon dioxide recycle stream using a separator before compression. By taking out NGLs in liquid form at this stage, the process avoids the need to compress and then condense them later, significantly reducing energy requirements while maximizing NGL recovery.

Inventive Principle:

Principle #2Taking out (Extraction)

2Productivity

If the carbon dioxide recycle stream is fully processed through compression and condensation, then NGL recovery is achieved, but energy consumption increases significantly

Engineering Contradiction:

ImproveNGL recovery rateVSAvoidenergy expenditure

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent performs preliminary separation of NGLs from the carbon dioxide recycle stream using a separator before compression. This preliminary action removes NGLs in liquid form, so they do not require subsequent compression and condensation steps, thereby achieving NGL recovery while minimizing energy expenditure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies partial action by selectively separating only the NGL components from the recycle stream rather than processing the entire stream through full compression and condensation. This partial processing approach achieves the necessary NGL recovery without the excessive energy expenditure of complete stream processing.

Inventive Principle:

Principle #16Partial or excessive action

3Productivity

If a separator is used to divide the recycle stream, then NGL recovery efficiency improves, but process complexity increases

Engineering Contradiction:

ImproveNGL recovery efficiencyVSAvoidprocess complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent uses a separator to segment the carbon dioxide recycle stream into distinct phases (purified CO2, NGLs, and water). This segmentation improves NGL recovery efficiency by isolating it for targeted handling, while the modular nature of the separator keeps the added process complexity manageable and localized to one unit operation.

Inventive Principle:

Principle #1Segmentation

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 method achieves a high-quality NGL recovery with lower energy consumption, improving process economics and feasibility by optimizing the NGL recovery rate and equipment sizing based on energy requirements, thereby enhancing the overall efficiency of the carbon dioxide reinjection process.

Implementation Method 1

The carbon dioxide recycle stream is separated into a purified carbon dioxide stream and a natural gas liquids stream

Methodology Applied

Scientific EffectPhase separation: Phase Change

Implementation Method 2

followed by a dehydrating process

Methodology Applied

Scientific EffectDehydration: Absorption (physical)

Data Source

PatentUS12474115B2Carbon dioxide recycle stream processing with ethylene glycol dehydrating in an enhanced oil recovery process

Publication Date: 2025.11.18 PILOT INTELLECTUAL PROPERTY LLC

AI summary

A set of process equipment for use in an enhanced oil recovery (EOR) process comprises first piping, a dehydrator, second piping, and a natural gas liquids recovery column. The first piping is configured to receive a wet carbon dioxide recycle stream from a recovery well. The dehydrator is configured to receive the wet carbon dioxide stream from the first piping and configured to dehydrate the wet carbon dioxide recycle stream using ethylene glycol to produce a dry carbon dioxide recycle stream. The second piping is configured to receive the dry carbon dioxide recycle stream from the dehydrator. The natural gas liquids recovery column is configured to receive the dry carbon dioxide recycle stream from the second piping and configured to separate the dry carbon dioxide recycle stream into a carbon dioxide reinjection stream and a natural gas liquids stream.