Parallel Distillation Columns with Vapor Recompression
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Solution Overview
Problem
Distillation processes using two columns consume significant energy, particularly for separating substances with low boiling points, due to the need for heating and condensing in heat exchangers and condensers.
Innovation Solution
A distillation device with two columns connected in parallel, utilizing a vapor recompressor to compress and heat exchange the overhead vapor of the second column with the bottom flow of the first column, reducing energy consumption by minimizing the energy required for condensation in the top condenser of the second column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two distillation columns are connected in parallel to increase throughput, then productivity is improved, but energy consumption increases due to additional heating and condensing requirements
Solution Approach 1:
The patent merges the heat exchange functions of multiple distillation columns by connecting the bottom outlet of one column to the top inlet of another, allowing the overhead vapor from the second column to serve as heating medium for the bottom flow of the first column. This integration eliminates the need for separate heat exchangers and condensers for each column, thereby maintaining increased throughput while significantly reducing total energy consumption.
Solution Approach 2:
The system enables self-service heat exchange where the overhead vapor from the second distillation column automatically provides the heating energy required for the bottom flow of the first column. The vapor's thermal energy is utilized to heat the liquid feed, and the condensed vapor then returns to the first column, creating a self-sustaining heat cycle that reduces external energy input requirements.
2Reliability
If overhead vapor is condensed through a condenser or refrigerator, then the distillation process is completed, but energy consumption increases significantly especially for low boiling point substances
Solution Approach 1:
The patent introduces an intermediary heat exchange mechanism where the overhead vapor from the second column is used to heat the bottom flow of the first column before condensation. This intermediary step allows the vapor to transfer its thermal energy productively to the feed stream, and the condensation process occurs at reduced energy cost since the vapor has already performed useful heating work.
Solution Approach 2:
The system utilizes phase transitions of the overhead vapor - allowing it to condense from vapor to liquid phase while transferring latent heat to the bottom flow in the heat exchanger. This phase change process is harnessed to provide heating energy, and the condensed liquid then returns to the distillation column, eliminating the need for high-energy refrigeration systems.
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 allows for high-purity product separation while significantly reducing energy consumption, especially in alkane/alkene separation processes, by optimizing heat exchange efficiency and reducing the load on refrigeration systems.
Implementation Method 1
a vapor recompressor configured to compress the overhead vapor of the second distillation column
Implementation Method 2
a heat exchanger configured to heat-exchange the compressed overhead vapor of the second distillation column with the bottom flow of the first distillation column
Implementation Method 3
the distillation process evaporates and separates the mixed materials of a binary system or more present in the feedstock by the difference in boiling points
Implementation Method 4
the distillation process evaporates and separates the mixed materials
Implementation Method 5
a high boiling substance is separated in the form of bottom condensate
Data Source
AI summary
A distillation device including: a first distillation column having first top, bottom and upper outlets and first upper and lower inlets; a second distillation column equipped with a top condenser and a bottom reboiler, and having second top, bottom and upper outlets and second upper and lower inlets; a vapor recompressor; a heat exchanger; a first supply line supplying a feedstock to the first lower inlet; a first connection line transferring a first bottom flow to the second lower inlet via the heat exchanger; and a second connection line transferring a second top flow to the top condenser via the heat exchanger after passing through the vapor recompressor. The first bottom flow flowing through the first connection line and the second top flow flowing through the second connection line are heat-exchanged in the heat exchanger. A distillation method of a feedstock using the distillation device.