Rectifier Reboiler Heat-Exchange Staging for C4 Separation
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Solution Overview
Problem
Conventional systems for separating 1,3-butadiene from C4 mixtures face reliability and stability issues due to the sensitivity of heat exchangers to changes in the purified solvent stream and susceptibility to fouling, affecting the production process.
Innovation Solution
A system and method that utilize steam as the heating medium for the last heat exchanger in the rectifier column reboiler, allowing independent control of heating parameters and reducing fouling, while also optimizing heat recovery by using the purified solvent stream in upstream exchangers and recovering extra heat in downstream units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the purified solvent stream is used as heating medium for the reboiler, then heat recovery is optimized, but the system reliability deteriorates due to sensitivity to solvent stream changes and fouling
Solution Approach 1:
The reboiler heating system is segmented into multiple heat exchangers arranged in series, where the first heat exchanger uses purified solvent stream for heat recovery and the second heat exchanger uses steam as heating medium. This segmentation allows the system to benefit from both heat recovery and enhanced reliability, as the steam heating provides a stable reference temperature that compensates for variations in solvent stream conditions.
2Reliability
If multiple heat exchangers in series are used in the reboiler, then heating performance can be controlled independently, but device complexity increases
Solution Approach 1:
The reboiler is divided into multiple heat exchangers in series, with each serving a specific function: the first for heat recovery using solvent stream, and the second for stable temperature control using steam. This segmentation provides independent control of heating performance while maintaining manageable system complexity through functional specialization.
3Reliability
If steam is used as heating medium in the last heat exchanger, then fouling is reduced and heating performance is stabilized, but energy efficiency decreases due to lower heat recovery
Solution Approach 1:
The heating system is segmented into two stages: the first heat exchanger maximizes heat recovery from the solvent stream, while the second heat exchanger uses steam to provide stable heating and prevent fouling. This segmentation allows the system to achieve both energy efficiency and operational reliability without compromising either objective.
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
Enhances the stability and reliability of 1,3-butadiene production by maintaining heat balance and reducing fouling, while optimizing heat recovery and utilization in downstream operations.
Implementation Method 1
the reboiler for the rectifier column can include two or more heat exchangers in series with the last of the heat exchangers in series using steam as heating medium
Implementation Method 2
the last of the heat exchangers in series using steam as heating medium
Implementation Method 3
enabling the heating performance of the reboiler to be manipulated independently from any process streams of the system
Implementation Method 4
the first one or more exchangers of the rectifier column reboiler can use purified solvent stream from the degasser column as heating medium, resulting in optimized heat integration of the system
Implementation Method 5
the extra heat provided to the system by the steam can be further recovered in the downstream operation units, further optimizing the heat recovery and maintaining heat balance for the system
Data Source
AI summary
A system and a method for separating C4 and recovering 1,3-butadiene are disclosed. The system includes a main washer column, a rectifier column for separating a bottom stream from the main washer column, an after washer column for purifying 1,3-butadiene from a side stream of the rectifier column comprising acetylenes and butadienes, a degasser column for separating a bottom stream from the rectifier column to produce a lean solvent stream. The lean solvent stream comprises primarily the solvent and about 8.3% water used in the main washer column and after washer column. A reboiler for the rectifier column includes one or more heat exchange units. At least one of the heat exchange units of the reboiler for the rectifier column uses steam as heating medium.