Recovery Column Reflux Recycling for Flexible Ethane Extraction
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Solution Overview
Problem
Existing natural gas processing technologies face challenges in achieving flexible ethane extraction rates while minimizing energy consumption, particularly at high recovery rates, which affects the efficiency and profitability of natural gas installations.
Innovation Solution
The process involves using a secondary reflux stream, compressing the bottom stream from the recovery column, and implementing heat exchange techniques between various streams within the fractionation and recovery columns to optimize ethane extraction and reduce energy consumption, allowing for adjustable ethane production without significantly modifying the installation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ethane extraction rate is increased, then the ethane production is improved, but the energy consumption increases
Solution Approach 1:
The invention changes the operating parameters of the distillation column, specifically optimizing the reflux ratio and column pressure to achieve high ethane extraction rates while minimizing energy consumption. By adjusting these parameters, the system can operate efficiently at different production levels without proportionally increasing energy input.
Solution Approach 2:
The invention introduces dynamic control capabilities that allow the system to adapt its operation in real-time based on market demand for ethane. The control system can dynamically adjust the ethane extraction rate by modifying reflux flows and column operating conditions, enabling flexible response to changing market conditions while maintaining energy efficiency.
2Use of energy by moving object
If the ethane extraction rate is reduced, then the energy consumption is reduced, but the C 3 + extraction rate is also reduced
Solution Approach 1:
The invention segments the hydrocarbon separation into distinct functional zones within the distillation column, with specific trays optimized for ethane extraction and others for propane and heavier hydrocarbons. This segmentation allows independent control of ethane and C3+ extraction rates, enabling the system to reduce ethane extraction for energy savings while maintaining C3+ extraction through separate control mechanisms.
Solution Approach 2:
The invention implements feedback control systems that continuously monitor the composition of product streams and adjust operating parameters accordingly. When ethane extraction is reduced to lower energy consumption, the feedback system compensates by adjusting reflux ratios and column conditions to maintain the desired C3+ extraction rate, ensuring both objectives are met simultaneously.
3Adaptability or versatility
If a double installation is provided, then the flexibility of ethane and C 3 + production is improved, but the device complexity increases
Solution Approach 1:
The invention designs the distillation column to perform multiple functions simultaneously - separating ethane, propane, and heavier hydrocarbons in a single integrated unit. By making the column multi-functional with strategically placed side draws and multiple reflux streams, the system achieves the flexibility of a double installation without the complexity of two separate units. The same column can be optimized for different production scenarios by adjusting operational parameters.
4Productivity
If the number of compressors is increased, then the ethane extraction rate is improved, but the energy consumption increases
Solution Approach 1:
The invention employs a reflux system where condensed overhead vapors are returned to the column to facilitate separation. This internal recycling mechanism performs part of the separation work that would otherwise require external compression, reducing the need for additional compressors. The reflux stream naturally provides the necessary mass flow and cooling to maintain high ethane extraction without proportionally increasing compression energy input.
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 enables flexible ethane extraction rates up to 85% while significantly reducing energy consumption and maintaining high propane extraction rates, thereby enhancing the operational efficiency and profitability of natural gas processing installations.
Implementation Method 1
The head stream is placed in a heat exchange relationship with the recycling stream and with the secondary reflux stream
Implementation Method 2
The recycling stream is cooled and condensed at least partially in the overhead condenser
Implementation Method 3
The cooled recycling stream is expanded in an expansion valve (156) to form an expanded cooled recycling stream (155)
Implementation Method 4
The expanded feed stream is introduced into a distillation column (35) known as a recovery column
Implementation Method 5
a cut of hydrocarbons in C 3 + and an ethane-rich stream
Data Source
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AI summary
The process comprises the following steps: - taking a recycling stream (152) from a top stream (131, 140, 141) resulting from a recovery column (35); - causing heat exchange between the recycling stream (152) and at least one part of the top stream (131) resulting from the recovery column (35), - reintroducing, after expansion, the cooled and expanded recycling stream into the recovery column (35). The process comprises taking at least one bottom reboiling stream (165) from the bottom of the recovery column (35), and causing heat exchange between the bottom reboiling stream and at least a part of the starting natural gas (13) and/or the recycling stream (152), wherein the bottom reboiling is provided by the heat taken from the starting natural gas stream (13) and/or from the recycling stream (152).