Two-Stage NGL Recovery Separation in CO2 Recycle Streams

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Solution Overview

Problem

The carbon dioxide reinjection process in hydrocarbon recovery systems faces inefficiencies in recovering natural gas liquids (NGLs) due to high energy requirements and complex separation processes, which affect the quality and quantity of recovered NGLs.

Innovation Solution

A method involving a two-stage separation process using a first separator to split a feed stream into a carbon dioxide recycle stream and a heavy hydrocarbon stream, followed by a second separator to further separate the recycle stream into purified carbon dioxide and natural gas liquids, optimizing NGL recovery while managing energy expenditure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If a single-stage separation process is used to separate NGLs from carbon dioxide recycle stream, then the separation process is simpler, but the NGL recovery rate is lower and energy consumption is higher

Engineering Contradiction:

ImproveNGL recovery rateVSAvoidenergy consumption

Core Design Contradiction:

ProductivityVSUse of energy by moving object

Solution Approach 1:

The separation process is divided into two distinct stages: a first separator that performs initial separation of the feed stream into heavy hydrocarbons and a recycle stream, and a second separator that further separates the recycle stream into purified carbon dioxide and NGLs. This segmentation allows each separator to be optimized for its specific function, improving overall NGL recovery efficiency while managing energy consumption through staged processing

Inventive Principle:

Principle #1Segmentation

2Productivity

If complex separation processes are used to improve NGL recovery, then NGL recovery rate increases, but the process complexity and energy requirements increase

Engineering Contradiction:

ImproveNGL recovery rateVSAvoidseparation process complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The complex separation task is segmented into two simpler, sequential separation stages. Each separator handles a specific portion of the separation workload, making the overall process more manageable and less complex than a single complex separation system, while still achieving high NGL recovery rates

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The first separator extracts heavy hydrocarbons from the feed stream, removing the bulk of the separation complexity. The second separator then extracts NGLs from the remaining recycle stream. This extraction approach simplifies each individual separation task while maintaining high overall recovery

Inventive Principle:

Principle #2Taking out (Extraction)

3Manufacturing precision

If high energy input is applied to separate NGLs from carbon dioxide, then separation efficiency improves, but energy consumption increases

Engineering Contradiction:

Improveseparation efficiencyVSAvoidenergy consumption

Core Design Contradiction:

Manufacturing precisionVSUse of energy by moving object

Solution Approach 1:

The separation process is segmented into two stages, allowing energy input to be distributed and optimized for each stage. The first separator operates at one set of conditions optimized for heavy hydrocarbon separation, while the second separator operates at different conditions optimized for NGL recovery, improving overall separation efficiency without requiring excessive energy at any single stage

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different operating parameters (temperature, pressure) are applied at each separation stage to optimize separation efficiency for the specific components being separated at that stage, rather than using uniform high-energy conditions throughout the entire process

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 approach enhances NGL recovery rates with reduced energy consumption, producing high-quality NGLs and purified carbon dioxide, thereby improving the economic feasibility of the carbon dioxide reinjection process.

Implementation Method 1

A feed stream is separated into a carbon dioxide recycle stream and a heavy hydrocarbon stream

Methodology Applied

Scientific EffectSeparation:

Implementation Method 2

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

Methodology Applied

Scientific EffectSeparation:

Data Source

PatentUS9200833B2Heavy hydrocarbon processing in NGL recovery system

Publication Date: 2015.12.01 PILOT INTELLECTUAL PROPERTY LLC

AI summary

A method for processing heavy hydrocarbons in an NGL recovery system is provided. In one embodiment, a feed stream is separated into a carbon dioxide recycle stream and a heavy hydrocarbon stream. The heavy hydrocarbon stream comprises carbon dioxide and natural gas liquids, and the heavy hydrocarbon stream comprises heavy hydrocarbons. 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. In another embodiment, a set of process equipment comprises a first separator and a second separator. The first separator is configured to separate a feed stream into a recycle stream and a heavy hydrocarbons stream, and the second separator is configured to separate the recycle stream into a purified recycle stream and a natural gas liquids stream.