LNG Mixing for Selective NGL Extraction and Dew Point Control
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Solution Overview
Problem
Current methods for extracting natural gas liquids (NGLs) from 'rich' natural gas are inefficient, particularly in achieving selective extraction and controlling hydrocarbon dew point, often requiring expensive cryogenic processes and complex equipment, and struggle with 'turndown' operations to adjust recovery levels.
Innovation Solution
The method involves mixing Liquid Natural Gas (LNG) with the 'rich' natural gas stream to lower its temperature to a selected dew point, allowing for selective condensation of NGLs without the need for cryogenic or refrigeration plants, using a series of heat exchangers and separators to control temperature and pressure, enabling flexible recovery ratios and dew point control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If cryogenic processes are used to extract NGLs, then ethane recovery increases to 99%, but operating costs increase significantly
Solution Approach 1:
The patent changes the temperature parameter from cryogenic levels to moderate refrigeration temperatures, achieving selective NGL extraction without the high operating costs of cryogenic processes. By controlling temperature to specific dew points, the system recovers desired NGL quantities efficiently.
Solution Approach 2:
The extraction process is segmented into multiple stages with different temperature settings, allowing selective recovery of different NGL components. This enables flexible turndown operations where only specific NGLs are extracted at different times, rather than requiring full cryogenic processing.
2Quantity of substance
If refrigeration plants are used to extract NGLs, then propane and butane extraction is effective, but the process cannot easily adjust to selective recovery modes
Solution Approach 1:
The system employs dynamic temperature control where the refrigeration temperature can be adjusted in real-time based on which NGLs need to be recovered. This allows the same plant to selectively target different NGL components by simply changing the operating temperature setpoint.
Solution Approach 2:
The refrigeration plant is designed to perform multiple functions by extracting different NGLs at different temperature levels. A single facility can recover propane, butanes, and other NGLs selectively by adjusting operating parameters, rather than requiring separate dedicated plants for each NGL type.
3Quantity of substance
If centralized processing plants are used, then NGL removal is effective, but the hydrocarbon dew point control is complex and expensive
Solution Approach 1:
The patent extracts only the necessary NGLs to achieve the desired dew point control, rather than removing all NGLs as in traditional centralized plants. By selectively extracting specific quantities of NGLs, the system simplifies the processing requirements while maintaining effective dew point control.
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 eliminates the need for expensive cryogenic plants and compressors, allows for efficient extraction and control of NGLs, and facilitates 'turndown' operations by adjusting temperature set points, ensuring consistent heating value and hydrocarbon dew point management.
Implementation Method 1
interacting a rich natural gas stream with Liquid Natural Gas by mixing Liquid Natural Gas into the rich natural gas stream to lower the temperature of the rich natural gas stream to a selected hydrocarbon dew point
Implementation Method 2
whereby a selected hydrocarbon liquid carried in the rich natural gas stream is condensed
Data Source
AI summary
A method for selective extraction of natural gas liquids from “rich” natural gas. The method involves interacting a rich natural gas stream with Liquid Natural Gas (LNG) by mixing Liquid Natural Gas into the rich natural gas stream to lower the temperature of the rich natural gas stream to a selected hydrocarbon dew point, whereby a selected hydrocarbon liquid carried in the rich natural gas stream is condensed.