Multi-Column Heat-Integrated Distillation System
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Solution Overview
Problem
Current distillation processes are inefficient in terms of energy usage, particularly when handling multi-component feed mixtures with high boiling points, as they often require significant external heat sources like high-pressure steam, which may not be available or cost-effective.
Innovation Solution
A multi-column distillation process where the bottom product from a first column is used as a utility stream to indirectly heat a second column via a heat-exchange reboiler, with adiabatic adjustment of temperature and pressure to optimize energy efficiency, reducing the need for external heat and minimizing fuel gas usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-pressure steam is used to heat the bottom liquid in distillation columns, then the heating requirement is met, but the cost and availability issues arise
Solution Approach 1:
The system uses the hot bottom liquid from the first column to heat the bottom liquid in the second column through a heat-exchange reboiler. This self-service approach eliminates the need for external high-pressure steam, reducing energy costs and improving availability while meeting the heating requirement of the second column.
Solution Approach 2:
The patent merges the heating function of multiple columns into a single integrated system. The hot bottom liquid from the first column serves dual purposes: maintaining the first column's operation and providing heat to the second column's reboiler, thereby consolidating energy usage and reducing external energy requirements.
2Temperature
If multiple fired reboilers or separate hot oil systems are used, then heating requirements are met, but energy efficiency decreases and costs increase
Solution Approach 1:
The system eliminates the need for separate fired reboilers or hot oil systems by using the hot bottom liquid from the first column to directly heat the second column's reboiler. This self-service approach reduces energy losses associated with multiple heating systems and external energy sources, improving overall energy efficiency.
Solution Approach 2:
The hot bottom liquid from the first column performs multiple functions: it maintains the first column's distillation process and simultaneously serves as the heating medium for the second column's reboiler. This multi-functionality replaces the need for multiple dedicated heating systems, reducing energy consumption and operational costs.
3Loss of energy
If the first bottom product is used as utility stream to heat the second reboiler, then energy efficiency improves, but the temperature and pressure adjustment complexity increases
Solution Approach 1:
The patent employs adiabatic pressure reduction valves to automatically adjust the pressure and temperature of the utility stream from the first column before it enters the second column's reboiler. This parameter change approach simplifies the adjustment process by using passive adiabatic expansion rather than active control systems, maintaining energy efficiency while reducing operational 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 process significantly reduces the amount of external heat required, leading to lower energy consumption and decreased CO2 emissions, while maintaining separation efficiency, as demonstrated in experimental examples.
Implementation Method 1
Heating the other part of the first bottom product in the first reboiler and returning to the first column as a first circulating reboiler stream; Taking part of the first circulating reboiler stream to provide heat to the second reboiler as a utility stream
Implementation Method 2
the temperature and pressure of said part of said utility stream are adiabatically adjusted before feeding to the second column
Implementation Method 3
Distillation is one of the most widely used separation techniques in the chemical industry. Standard distillation methods typically introduce a multi-component feed -that is a mixture of two or more miscible components having different boiling points- to a distillation column, apply heat at the bottom of the column and cool at the top. The different components in the feed will therefore separate according to their respective boiling points between the top and bottom of the column.
Data Source
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AI summary
The invention relates to a process for separating a multi-component feed mixture in a distillation system comprising a first distillation column having a first fired reboiler, and at least a second distillation column having a second heat-exchange reboiler, comprising the steps of a) introducing the feed mixture to the first column, and separating into at least a first top and a first bottom product; b) taking part of the first bottom product for providing heat to the second reboiler as a utility stream; and c) feeding part of said utility stream after heat-exchange as main feed to the second column for further separation. This process allows significant energy savings, by reduction of the amount of external heat required for the fired reboiler and omission of a conventionally used heat-exhanger. The invention also relates to such distillation system suitable for separating a multi-component mixture with the process of the invention.