Ethylene Distributor Column Layout for Lower-Energy Purification
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Solution Overview
Problem
Conventional distillation methods for ethylene recovery and purification in steam cracking furnaces are energy-inefficient due to the need for multiple phase changes and lack of optimization in thermal coupling between columns, leading to high energy consumption and suboptimal hydrogen recovery.
Innovation Solution
A partially coupled distillation system is employed, which includes an ethylene distributor column and selective thermal coupling, along with a mixed refrigerant system, to reduce energy requirements and enhance hydrogen recovery by making a rough separation of methane and hydrogen downstream of the ethylene distributor column.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional sharp-split distillation is used for ethylene recovery, then separation purity is improved, but energy consumption increases due to multiple phase changes
Solution Approach 1:
The separation process is divided into multiple functional sections within a single distillation column: a deethanizer section for removing C1 components, a C2 splitter section for separating ethylene from ethane, and a propylene section for C3 recovery. This segmentation allows each section to operate at optimized conditions while reducing total phase changes compared to conventional sharp-split distillation
Solution Approach 2:
The patent introduces a vertical dimensional arrangement of multiple separation sections within one column, with feed入口处 positioned between the deethanizer and C2 splitter sections. This spatial arrangement enables simultaneous operation of different separation functions at different heights, reducing the need for multiple separate columns and associated phase changes
2Use of energy by moving object
If fully thermally coupled distillation system is employed, then energy efficiency is improved, but operational flexibility deteriorates
Solution Approach 1:
The distillation column is designed with adjustable operating parameters including variable feed location, adjustable reflux ratios for different sections, and flexible product draw-off points. This dynamic design allows the system to adapt to different feed compositions and market demands while maintaining thermal coupling benefits
Solution Approach 2:
The single distillation column performs multiple functions simultaneously: deethanization, ethylene/ethane separation, and propylene recovery. This multi-functionality provides operational flexibility to handle various feedstocks and product requirements while maintaining energy efficiency through integrated thermal coupling
3Manufacturing precision
If multiple distillation columns are used for complete separation, then purification efficiency is improved, but device complexity increases
Solution Approach 1:
Multiple distillation functions that would traditionally require separate columns are merged into a single integrated distillation column. The column contains distinct sections for deethanization, C2 splitting, and propylene recovery, all operating simultaneously with shared reboiler and condenser systems, thereby reducing equipment complexity while maintaining purification 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 significant energy savings and improved hydrogen recovery, with a more efficient process that reduces the number of phase changes and optimizes energy usage compared to fully coupled systems, while maintaining operational efficiency.
Implementation Method 1
separating the ethylene distributor overhead vapor stream into a light stream enriched in hydrogen and one or more streams depleted in hydrogen and comprising ethylene, said separation comprising at least one step of chilling at least a portion of the ethylene distributor overhead vapor stream
Implementation Method 2
directing the gas mixture to a first distillation column and recovering therefrom a first vapor overhead stream comprising ethane, ethylene, acetylene, hydrogen and methane and a first bottoms stream comprising components heavier than ethane
Data Source
AI summary
A process for the recovery and purification of ethylene and optionally propylene from a stream containing lighter and heavier components that employs an ethylene distributor column and a partially thermally coupled distributed distillation system.