Integrated methods and configurations for propane recovery in both ethane recovery and ethane rejection

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Solution Overview

Problem

Conventional natural gas liquids (NGL) technologies face challenges in efficiently switching between ethane recovery and rejection modes, often resulting in significant losses of propane recovery and energy inefficiency, as they are typically configured for either ethane recovery or propane recovery, but not both effectively.

Innovation Solution

A natural gas liquids plant configuration featuring an absorber and a stripper, coupled with a multi-pass heat exchanger, allows for operation in both ethane rejection and recovery modes by adjusting reflux streams and pressures, maintaining over 98% propane recovery during ethane rejection and achieving high ethane recovery during ethane recovery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional NGL technologies switch between ethane recovery and rejection modes, then operational flexibility is improved, but energy efficiency deteriorates

Engineering Contradiction:

Improvemode switching capabilityVSAvoidenergy efficiency

Core Design Contradiction:

Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent prepares the system for mode switching by pre-configuring the absorber and stripper equipment to handle both recovery and rejection modes. The preliminary setup of adjustable pressure control systems and flexible reflux routing minimizes the energy penalty during transitions, as the infrastructure is already in place rather than requiring major reconfigurations

Inventive Principle:

Principle #10Preliminary action

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 configuration enables seamless switching between ethane rejection and recovery modes, maintaining high propane recovery during ethane rejection and achieving over 98% ethane recovery, thereby optimizing plant revenues and energy efficiency.

Implementation Method 1

high pressure feed gas stream is cooled by heat exchangers

Methodology Applied

Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

the hydrocarbon liquids are condensed and separated from the chilled gas

Methodology Applied

Scientific EffectCondensation: Condensation

Implementation Method 3

the cooled vapor is expanded and fractionated in distillation columns

Methodology Applied

Scientific EffectAdiabatic expansion cooling: Adiabatic Cooling

Implementation Method 4

The cooled vapor is expanded and fractionated in distillation columns (e.g., deethanizer or demethanizer)

Methodology Applied

Scientific EffectFractional distillation: Distillation

Data Source

PatentUS20210095921A1Integrated methods and configurations for propane recovery in both ethane recovery and ethane rejection

Publication Date: 2021.04.01 FLUOR TECH CORP

AI summary

A natural gas liquids (NGL) plant, the NGL plant comprising an absorber configured to provide an absorber overhead and an absorber bottoms, a stripper configured to produce a stripper overhead and a stripper bottoms, wherein the stripper is positioned downstream from the absorber and fluidly connected therewith such that the absorber bottoms can be introduced into the stripper, and a multi-pass heat exchanger configured to provide at least one reflux stream to the absorber, wherein the absorber and stripper are configured, in an ethane rejection arrangement, to provide the stripper overhead to a top of the absorber, and wherein the absorber and stripper are configured, in an ethane recovery arrangement, to provide the stripper overhead to a bottom of the absorber.