Propylene Splitter Compressor Reboiler for Single-Stage Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional cryogenic separation systems for propylene production are inefficient and costly, requiring further fractionation to separate C2− and C3 hydrocarbons, which necessitates additional refrigeration and increased capital costs.
Innovation Solution
The process involves reboiling the propylene-propane splitter bottoms stream through heat exchange with a compressed propylene splitter overhead stream and/or deethanizer bottoms stream, optimizing the use of heat and reducing the need for elevated pressures and additional compression stages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional cryogenic separation systems are used to separate hydrogen from light hydrocarbons, then separation is achieved, but additional refrigeration packages and capital costs are required for further fractionation in deethanizer columns
Solution Approach 1:
The patent combines the deethanizer column and propylene-propane splitter into a single integrated distillation column. The deethanizer section separates hydrogen and light hydrocarbons (C2-) in the upper portion, while the propylene-propane splitter section separates C3 hydrocarbons in the lower portion. This merging eliminates the need for a separate deethanizer column and its associated refrigeration package, reducing capital costs and system complexity while maintaining separation efficiency through continuous internal reflux and heat integration within the unified column structure
Solution Approach 2:
The single integrated column performs multiple separation functions simultaneously: it acts as both a deethanizer for removing C2- materials and a propylene-propane splitter for C3 separation. The column achieves this multi-functionality through strategically placed feed points, side draws, and internal reflux sections that enable independent operation of each separation function within the same physical structure, eliminating the need for separate dedicated columns for each separation task
2Reliability
If conventional cryogenic separation systems cool process streams to remove hydrogen, then hydrogen separation is achieved, but further fractionation requires additional refrigeration packages
Solution Approach 1:
The patent converts the cold energy that would otherwise be wasted in conventional systems into a useful resource. The expanded overhead stream from the integrated column, which is cold due to flash expansion, is routed to cool process feeds entering the column. This heat integration captures the cold energy that would be discarded and uses it to pre-cool feeds, reducing or eliminating the need for additional refrigeration packages while maintaining the required temperature profiles for hydrogen separation and further fractionation
Solution Approach 2:
The system maintains continuous useful thermal action through internal heat integration within the integrated column. Condensate from the overhead stream provides continuous reflux cooling in the upper deethanizer section, while the lower splitter section operates with continuous internal reflux. This continuous thermal circulation eliminates dead zones where energy would be wasted and maintains optimal temperature gradients throughout the column for efficient hydrogen separation and C3 fractionation without requiring intermittent or additional refrigeration cycles
3Manufacturing precision
If deethanizer columns are used for further fractionation, then C2- and C3 hydrocarbon separation is achieved, but capital costs increase
Solution Approach 1:
The patent merges the deethanizer column and propylene-propane splitter into a single integrated distillation column with distinct operational sections. The upper portion performs deethanization to separate C2- materials, while the lower portion performs propylene-propane splitting. This physical merging into one column structure eliminates the need for a separate deethanizer capital investment while achieving the same fractionation precision through carefully designed internal reflux sections, feed points, and side draws that maintain independent separation performance for each hydrocarbon fraction
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 enhances the efficiency and cost-effectiveness of propylene production by eliminating the need for elevated pressures and second-stage compression, thereby saving capital costs and improving the separation of propylene from propane and hydrogen.
Implementation Method 1
reboil the splitter bottoms stream by heat exchange with the compressed splitter overhead stream
Implementation Method 2
reboiling the propylene-propane splitter bottoms stream through heat exchange
Data Source
AI summary
A process and apparatus reboil a propylene splitter bottoms by heat exchange and/or a deethanizer bottoms stream with a compressed propylene splitter overhead stream. Use of single splitter compressor and operation of the propane-propylene splitter column at lower pressure are enabled, whereas conventionally two splitter compressors and higher splitter pressure were necessary to provide a propylene product stream and a propane recycle stream of equivalent quality.