Compact Gas Processing Assembly for High C2/C3 Recovery
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Solution Overview
Problem
Existing gas processing plants face inefficiencies in recovering C2 and C3 components due to the lack of additional rectification in demethanizer processes, requiring surplus compression capacity and additional capital and operating costs, especially in plants without upper absorber sections or surplus compression capacity.
Innovation Solution
A novel process that integrates additional rectification by using a compact arrangement of equipment to provide indirect cooling and mass transfer, eliminating the need for separate residue gas compression and reflux recycling, thereby enhancing recovery efficiency and reducing capital and operating costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional demethanizer processes are used without additional rectification, then capital costs and operating costs are reduced, but C2 and C3 component recovery efficiency decreases
Solution Approach 1:
The patent combines the rectification function with the existing demethanizer process by integrating a rectifying section that utilizes the overhead vapor stream. This merging approach adds separation capability without requiring entirely separate equipment systems, thereby improving C2 and C3 recovery efficiency while limiting the increase in device complexity.
Solution Approach 2:
The overhead vapor stream from the demethanizer is put to multi-use: it serves both as a product stream and as a rectifying agent within the rectifying section. This multi-functionality allows the system to achieve additional separation benefits without proportionally increasing capital investment or operating complexity.
2Productivity
If additional rectification equipment is added to improve separation, then C2 and C3 component recovery increases, but capital investment increases
Solution Approach 1:
The rectifying section is designed to be dynamically integrated with the existing demethanizer operation, utilizing variable overhead vapor flows to adjust rectification intensity. This dynamic approach allows the system to achieve improved C2 and C3 recovery without requiring fixed, capital-intensive additional equipment, thereby limiting capital investment while maintaining high productivity.
3Manufacturing precision
If surplus compression capacity is used for reflux recycling, then separation efficiency improves, but operating costs increase
Solution Approach 1:
The system uses its own overhead vapor stream to provide the rectifying function, eliminating the need for external compression capacity dedicated to reflux recycling. The overhead vapor naturally condenses and provides reflux, making the system self-sufficient and avoiding additional operating costs associated with surplus compression capacity while maintaining high separation efficiency.
4Productivity
If separate residue gas compression and reflux recycling systems are used, then recovery efficiency improves, but device complexity and capital costs increase
Solution Approach 1:
The patent merges the rectification function with the existing demethanizer overhead vapor handling system. By integrating the rectifying section to directly utilize the overhead vapor stream, the system achieves improved recovery efficiency without requiring separate compression and recycling infrastructure, thereby limiting the increase in device complexity and capital costs.
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 achieves C2 recoveries exceeding 99% and C3 recoveries of 96% without additional power consumption, significantly increasing product recovery and reducing capital costs, while minimizing environmental emissions by reducing piping and potential leak sources.
Implementation Method 1
The heat exchange means is configured to provide heat exchange between the substantially condensed stream and the recycle stream, and a combined stream arising from the rectifying section, so that the substantially condensed stream is cooled and the recycle stream is condensed to substantial condensation
Implementation Method 2
The mass transfer means is configured to provide mass transfer between the further condensed stream and the column overhead vapor stream, so that C2, C3 and heavier components are absorbed from the vapor stream
Implementation Method 3
The flash expanded stream is supplied to the heat exchange means in the rectifying section to provide indirect cooling to the combined stream arising from the mass transfer means
Data Source
AI summary
A process and an apparatus are disclosed for a compact processing assembly to improve the recovery of C2 (or C3) and heavier hydrocarbon components from a hydrocarbon gas stream. The preferred method of separating a hydrocarbon gas stream generally includes producing at least a substantially condensed first stream and a cooled second stream, expanding both streams to lower pressure, and supplying the streams to a fractionation tower. In the process and apparatus disclosed, the tower overhead vapor is directed to an absorbing means and a heat and mass transfer means inside a processing assembly. The outlet vapor from the processing assembly is compressed to higher pressure and cooled, then a portion is substantially condensed in a heat exchange means inside the processing assembly, expanded to lower pressure, and supplied to the heat and mass transfer means to provide cooling. Condensed liquid from the absorbing means is fed to the tower.