Single-Vessel Rectifying and Stripping Column Layout for Lower Energy Use
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Solution Overview
Problem
Propane dehydrogenation processes for producing olefins like propylene require significant energy input, leading to high costs and operational inefficiencies due to the need for extensive boiling, pressurization, and processing steps.
Innovation Solution
A fractionation system comprising a single vessel with a rectifying column and a stripping column of uniform diameter, where the rectifying column is positioned above the stripping column, allowing for efficient separation and reheat integration to reduce energy consumption and capital costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate vessels are used for rectifying and stripping columns, then each column can be optimized independently, but capital costs and device complexity increase
Solution Approach 1:
The patent combines the rectifying column and stripping column into a single integrated fractionation system housed in one vessel. The rectifying column is positioned in the upper portion and the stripping column in the lower portion, sharing common infrastructure such as reboilers and control systems. This merging reduces capital costs by eliminating the need for separate vessels while maintaining the functional independence needed for optimized operation of each column section.
2Manufacturing precision
If extensive boiling and pressurization steps are used, then separation efficiency is improved, but energy consumption increases
Solution Approach 1:
The integrated fractionation system enables continuous separation operations where the rectifying and stripping columns work in conjunction to continuously separate propylene from propane. The system maintains continuous vapor-liquid equilibrium stages throughout both column sections, eliminating the need for intermittent batch operations or multiple discrete processing steps, thereby improving separation efficiency while reducing overall energy consumption through optimized heat integration.
Solution Approach 2:
The system utilizes vapor-liquid phase transitions in both the rectifying and stripping columns to achieve separation. By optimizing the phase equilibrium conditions in each section and integrating the phase change processes, the system achieves high separation efficiency with reduced energy input compared to conventional multi-step boiling and pressurization methods.
3Manufacturing precision
If multiple distillation columns are used, then product purity is improved, but operating costs and process complexity increase
Solution Approach 1:
The patent merges the functions of multiple distillation columns into a single integrated fractionation system with rectifying and stripping sections. This consolidation maintains the ability to achieve high product purity through multiple theoretical stages while reducing operating costs by eliminating redundant equipment, reducing maintenance requirements, and simplifying operational procedures. The integrated system allows for coordinated control of both sections to optimize purity outcomes.
Solution Approach 2:
The single vessel housing both rectifying and stripping columns serves multiple functions simultaneously: it performs both rectification and stripping operations, houses integrated reboiler systems, and provides unified control mechanisms. This multi-functionality achieves the separation performance of multiple columns while reducing the number of independent systems that would increase operating costs and complexity.
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 configuration simplifies control and operation, reduces capital and operating costs, and achieves high recovery rates of propylene while minimizing unreacted propane recycle, thereby enhancing energy efficiency and cost savings.
Implementation Method 1
a de-ethanizer distillation column where ethane and lighter components are recovered as an overhead gas, and propane and propylene, and heavy boiling compounds are removed as bottoms
Implementation Method 2
at least a portion of the bottoms stream from the rectifying column is reheating reheated in a rectifying column reboiler, and at least a portion of the bottoms stream from the stripping column is reheated in a stripping column reboiler
Implementation Method 3
The overhead stream from the de-ethanizer is communicated to a condenser where the overhead stream is condensed
Data Source
AI summary
Fractionation systems utilizing a single rectifying column with a stripping column housed in the same vessel and having a uniform diameter are described. Methods of separating feed streams using the fractionation systems are also described.