Extractive Distillation Heat Integration for Butene Separation
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Solution Overview
Problem
Existing processes for the separation of butenes from C4-hydrocarbon streams by extractive distillation face challenges in achieving maximum energy recovery with minimal plant engineering complexity.
Innovation Solution
The process involves partial evaporation of the C4-hydrocarbon stream, contact with a solvent like NMP in an absorber, heat integration using the solvent's heat for preheating and evaporation in various stages, and recycling of the solvent to enhance energy recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If heat integration is implemented to maximize energy recovery, then energy utilization is improved, but plant engineering complexity increases
Solution Approach 1:
The patent combines multiple heat integration functions into a single heat exchanger unit. The heat exchanger simultaneously performs preheating of the C4-hydrocarbon stream, evaporation of the liquid stream, and heating of the solvent stream, eliminating the need for multiple separate heat integration devices and reducing overall plant complexity while maximizing energy recovery.
Solution Approach 2:
The heat exchanger is designed with multi-functionality, serving as a universal heat transfer device that handles multiple process streams with different temperature and phase requirements. It can handle gas-phase C4-hydrocarbon preheating, liquid-phase evaporation, and solvent heating all within the same equipment, reducing the number of components needed.
2Loss of energy
If multiple heat integration steps are implemented, then energy recovery is improved, but process complexity increases
Solution Approach 1:
The patent merges multiple heat transfer operations into a single integrated heat exchanger system. Instead of implementing separate heat exchangers for preheating, evaporation, and solvent heating, the invention combines these functions into one device that handles all heat integration steps simultaneously, thereby reducing process complexity while maintaining high energy recovery.
Solution Approach 2:
The heat exchanger is designed with multiple sections or zones that handle different heat transfer functions. The device is segmented into regions for gas-phase heating, liquid-phase evaporation, and solvent heating, allowing each function to be optimized independently while being integrated into a single piece of equipment.
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 allows for efficient energy recovery with reduced complexity, optimizing the use of solvent heat for preheating and evaporation, thereby improving the overall energy utilization in the separation process.
Implementation Method 1
contact with a solvent like NMP in an absorber, heat integration using the solvent's heat for preheating and evaporation in various stages
Implementation Method 2
at least partially evaporating the liquid C4-hydrocarbon stream in a feed evaporator
Implementation Method 3
passed through an absorber evaporator and then passed into the bottom of the absorber below the liquid collector to outgas predominantly butanes from the laden solvent
Implementation Method 4
the heat of the solvent withdrawn as a bottoms stream of the desorber is used at least partially for heat integration by employing the heat of the solvent in at least one respective heat exchanger for preheating the laden solvent passed to the desorber
Data Source
AI summary
A process for removing butenes from C4-hydrocarbon streams containing butanes and butenes involves extractive distillation with a suitable solvent. The process also involves heat integration, which allows utilization of the heat of the solvent for heating and/or at least partly evaporating various streams.