Lean Oil Absorption and Stabilization for NGL Recovery
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Solution Overview
Problem
Lean oil absorption, a traditional method for capturing natural gas liquids, is less effective compared to other technologies like the Gas Subcooled Process, and existing gas processing units face challenges in stabilizing and utilizing low-pressure liquid drips, leading to inefficiencies in hydrocarbon recovery and increased losses of valuable components like ethane and propane.
Innovation Solution
A process that utilizes a lean gas absorber in combination with a stabilization system, where low-pressure drips and stabilized gasoline are used to enhance the absorption of lighter hydrocarbons, with the stabilized gasoline serving as a finishing liquid and the low-pressure drip feeding a few stages below, allowing for improved separation and recycling of hydrocarbons, thereby increasing the overall capacity and efficiency of natural gas liquid recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional lean oil absorption is used to capture natural gas liquids, then the process can remove NGL's from natural gas, but the effectiveness is lower compared to other technologies like Gas Subcooled Process, resulting in loss of valuable components like ethane and propane
Solution Approach 1:
The patent changes the physical state parameter of the lean oil from ambient temperature liquid to subcooled liquid at lower temperatures. This parameter change enhances the absorption effectiveness of the lean oil, allowing it to capture lighter components like ethane and propane more effectively, thereby reducing substance loss while improving productivity
Solution Approach 2:
The patent creates a copy of the lean oil absorption process by using a stabilizer column to produce a stabilized lean oil that mimics the properties of commercial lean oil. This copied process achieves comparable or superior absorption effectiveness without requiring external commercial lean oil purchases
2Ease of operation
If commercial lean oil is purchased for absorption, then the absorption process can function, but the cost increases and the process requires makeup solvent tanks and solvent recovery systems
Solution Approach 1:
The patent implements self-service by using the plant's own stabilizer column to produce stabilized lean oil from the NGL recovery process. This self-generated lean oil circulates through the absorber, eliminating the need for external commercial lean oil purchases and the associated makeup solvent tanks and solvent recovery systems
Solution Approach 2:
The patent merges the lean oil generation function with the existing NGL recovery process by integrating the stabilizer column into the process flow. The stabilizer column produces lean oil as a byproduct of NGL recovery, combining two functions into one system and eliminating separate solvent management equipment
3Stability of the object's composition
If low pressure liquid drip is sent to tanks for weathering, then the liquid can be stabilized for transport, but valuable light ends are lost and the process is inefficient
Solution Approach 1:
The patent uses the lean oil in the absorber as an intermediary to capture the light ends from low pressure liquid drip before they can weather off. The lean oil absorbs the valuable components, preventing their loss, while the stabilizer column subsequently separates and recovers these components for reuse in the lean oil circulation
Solution Approach 2:
The patent converts the potentially harmful effect of light ends weathering off into a benefit by using these light ends to enrich the lean oil in the absorber. The light ends that would otherwise be lost are captured and concentrated in the lean oil, which is then regenerated in the stabilizer column and returned to service, turning a loss into a resource
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 effectively increases the recovery of ethane, propane, and heavier hydrocarbons, enhancing the capacity of gas processing units and reducing losses, by utilizing the stabilization system to produce high-quality lean oil for recycling and further separation, ultimately increasing revenue and processing efficiency.
Implementation Method 1
Lean oil absorption is a process in which the NGL's are removed by contacting the natural gas with a liquid hydrocarbon solvent (oil)
Implementation Method 2
sending the heavier hydrocarbon portion to a column to be separated into a light hydrocarbon portion comprising methane and ethane exiting a top of the column, a heavy hydrocarbon portion exiting a bottom of the column comprising pentanes and heavier hydrocarbons and a middle portion comprising butanes and propanes
Implementation Method 3
stabilizer reboiler for stabilizing the heavy hydrocarbon stream
Implementation Method 4
produce a stabilized natural gasoline product
Data Source
AI summary
The invention provides a process and a system for processing hydrocarbon streams efficiently, especially natural gas streams that contain natural gas liquids including propanes, butanes, pentanes and higher hydrocarbons. A lean oil absorber is used to separate natural gas liquids, a side stripper with a side stripper reboiler is used to separate a propane/butane stream and a stabilizer reboiler is used to stabilize a natural gasoline product stream.