Parallel Product Splitters for Olefin Separation Energy Recovery
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Solution Overview
Problem
Conventional dehydrogenation processes for producing propylene from propane are energy-intensive, requiring high input energy and lacking an efficient method for energy recovery, leading to significant energy consumption.
Innovation Solution
The process employs two product splitters operating in parallel, one at higher pressure and the other at lower pressure, utilizing exhaust steam from steam turbines to supply heat to the reboilers, thereby reducing energy consumption by recovering and reusing previously lost energy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a single product splitter is used at high pressure with steam reboiling, then propylene separation is achieved, but energy consumption is excessive due to lack of heat recovery
Solution Approach 1:
The single product splitter is divided into two parallel product splitters operating at different pressures (first at high pressure, second at low pressure). This segmentation allows the system to recover and reuse steam energy that would otherwise be lost, as the condensed steam from the first splitter can provide heat to the second splitter, thereby reducing overall energy consumption while maintaining separation effectiveness.
Solution Approach 2:
Instead of discarding the steam after it condenses in the first product splitter, the system recovers and reuses this steam as the heat source for the second product splitter. This recovery principle transforms what would be waste energy into a useful resource, significantly reducing the need for external steam generation and lowering overall energy consumption.
2Loss of energy
If exhaust steam from steam turbines is recovered and reused, then energy consumption is reduced, but process complexity increases due to additional equipment and configuration
Solution Approach 1:
The system merges the steam recovery function with the propylene separation function by integrating the two product splitters in parallel configuration. The exhaust steam from the steam turbine is combined with the heat exchange network of the dual splitter system, allowing simultaneous energy recovery and separation operations. This merging eliminates the need for separate heat recovery equipment while achieving both objectives.
Solution Approach 2:
The first product splitter serves dual functions: it separates propylene from propane and simultaneously acts as a heat exchanger that recovers steam energy for use in the second splitter. This multi-functionality reduces the need for dedicated heat recovery equipment and simplifies the overall system configuration while improving energy efficiency.
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 results in a 18-22% reduction in total energy consumption compared to conventional methods, enabling the production of high purity propylene with lower energy expenditure.
Implementation Method 1
The low pressure product splitter has a reboiler that has heat supplied using a heat pump
Implementation Method 2
The high pressure product splitter operates at a higher pressure and has a reboiler that has heat supplied using exhaust steam from the steam turbines of the product compressor and the heat pump
Implementation Method 3
In the product splitter column, propylene is recovered as an overhead stream and unreacted propane from the bottoms stream of the product splitter is recycled back to the dehydrogenation unit
Data Source
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AI summary
Improved processes for the separation of olefins from paraffins, such as propylene from propane are provided. Two product splitters are used in parallel to separate propylene from propane. One of the product splitters operates at a lower pressure, while the second product splitter operates at a higher pressure. The use of the two splitters in parallel provides a process for recovery of a high purity propylene product with lower energy consumption compared to prior art processes.