NGL Recovery Process Without a Demethanizer Column
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Solution Overview
Problem
Current NGL recovery technologies require expensive demethanizer columns and are inefficient in extracting C2+ and C3+ components, lacking flexibility and high recovery rates, especially in offshore and retrofitted facilities.
Innovation Solution
A process utilizing heat exchangers, compression, and simple separation vessels for selective extraction of NGLs without a demethanizer column, employing expansion and separation sequences to achieve deep extraction of C2+ and C3+ components, with options for ethane extraction or rejection, and suitable for offshore and retrofitted facilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If demethanizer columns are used for NGL recovery, then separation capability is improved, but capital cost and device complexity increase significantly
Solution Approach 1:
The invention extracts and eliminates the demethanizer column from the traditional NGL recovery process. By using a series of expansion assemblies and separation vessels, the process achieves effective separation of C2+ and C3+ components without requiring the complex demethanizer column, thus reducing device complexity while maintaining separation capability
Solution Approach 2:
The invention segments the single complex demethanizer column into multiple simpler units: several expansion assemblies and separation vessels arranged in sequence. This segmentation allows each unit to perform a specific function (expansion, cooling, separation) at a lower complexity level, collectively achieving the overall separation goal
2Quantity of substance
If demethanizer columns are installed, then NGL recovery is achieved, but capital expenses and operational costs increase
Solution Approach 1:
The invention replaces expensive, complex demethanizer columns with simpler, less costly expansion assemblies and separation vessels. These simpler units achieve the same NGL recovery function at a fraction of the capital cost, aligning with the principle of using cheaper alternatives when performance requirements are met
Solution Approach 2:
The invention changes the operating parameters and process approach by using expansion cooling and sequential separation instead of thermal distillation in demethanizer columns. This parameter change enables effective NGL recovery through physical expansion and phase separation, eliminating the need for energy-intensive heating and cooling cycles required by traditional columns
3Productivity
If traditional separation processes are used, then C2+ and C3+ extraction is performed, but recovery rates are insufficient
Solution Approach 1:
The invention applies preliminary expansion and cooling actions to the feedstock before separation. By pre-cooling the hydrocarbon stream through expansion assemblies, the process enhances the efficiency of subsequent separation steps, achieving higher recovery rates of C2+ and C3+ components from the outset
Solution Approach 2:
The invention implements a continuous process where expansion assemblies and separation vessels operate in sequence without interruption. The effluent from each separation vessel is continuously fed to the next expansion or separation unit, maintaining continuous useful action that maximizes recovery efficiency throughout the process
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 demethanizer columns, reduces capital and operational expenses, achieves high recovery rates of C2+ and C3+ components, and meets pipeline specifications, while being adaptable to various gas pressures and compositions.
Implementation Method 1
cooling the pressurized feedstock stream in an LNG heat exchanger
Implementation Method 2
further cooling the cooled stream from the heat exchanger via a first gas expansion assembly
Implementation Method 3
separating the further cooled stream in a first gas/liquid separation vessel assembly into gas and liquid streams
Implementation Method 4
pumping the liquid stream (0-100%) from the first separation vessel assembly into the heat exchanger
Data Source
AI summary
This process comprises using unconventional processing of hydrocarbons, e.g. natural gas, for recovering C2+ and NGL hydrocarbons that meet pipeline specifications, without the core high capital cost requirement of a demethanizer column, which is central to and required by almost 100% of the world's current NGL recovery technologies. It can operate in Ethane Extraction or Ethane Rejection modes. The process uses only heat exchangers, compression and simple separation vessels to achieve specification ready NGL. The process utilizes cooling the natural gas, expansion cooling, separating the gas and liquid streams, recycling the cooled streams to exchange heat and recycling selective composition bearing streams to achieve selective extraction of hydrocarbons, in this instance being NGLs. The compactness and utility of this process makes it feasible in offshore applications as well as to implementation to retrofit/revamp or unload existing NGL facilities. Many disparate processes and derivatives are anticipated for its use.