CDO Zeolite PSA for Ethylene Separation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current ethylene-ethane separation processes in polyethylene plants require large distillation towers and high energy consumption, making it inefficient to recycle or recover stranded ethylene gas streams, and existing membrane technologies have limited selectivity.
Innovation Solution
A pressure-swing adsorption (PSA) process using zeolite particles with a CDO framework as adsorbent material, which alternates between adsorption and desorption steps to selectively remove impurities like ethane, hydrogen, and nitrogen, achieving high ethylene purity without distillation or thermal processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If distillation towers are used for ethylene-ethane separation, then separation purity can be achieved, but energy consumption and device complexity increase significantly
Solution Approach 1:
The patent employs zeolite adsorbent materials with specific pore structures (small pore size 3x3, 3x4, or 3x5 angstroms) that selectively adsorb ethylene from the gas phase. The porous structure enables molecular-level separation based on size and shape differences between ethylene and ethane, achieving high purity separation without requiring large distillation towers or high energy input.
Solution Approach 2:
The invention utilizes pressure swing adsorption (PSA) technology that changes the pressure parameter to control adsorption and desorption cycles. By cycling pressure between high (for adsorption) and low (for desorption), the system achieves continuous separation and regeneration of the adsorbent, enabling energy-efficient ethylene recovery without thermal processes.
2Device complexity
If membrane technologies are used for ethylene separation, then device complexity is reduced, but selectivity and separation efficiency remain limited
Solution Approach 1:
The patent employs composite adsorbent systems combining zeolite particles with specific framework structures (CDO, CDS, or RTH) and binder materials to create optimized adsorption beds. This composite approach enhances both the selectivity for ethylene and the mechanical properties of the adsorbent bed, achieving superior separation performance compared to simple membrane technologies while maintaining relatively simple device architecture.
3Use of energy by stationary object
If PSA units are deployed for stranded ethylene recovery, then energy consumption is reduced, but vacuum power requirements and process feasibility must be optimized
Solution Approach 1:
The patent divides the separation process into multiple adsorption beds that operate in sequence through the PSA cycle. This segmentation allows continuous processing where one bed is adsorbing while another is being regenerated, optimizing vacuum power consumption and enabling feasible deployment for stranded ethylene recovery at various scales.
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
The PSA process reduces vacuum power consumption and achieves ethylene recovery up to 98 mol% purity, enabling efficient deployment and competitive use of PSA units for stranded ethylene gas recovery.
Implementation Method 1
The contact occurs at a feed pressure of from about 50 to about 500 psia for a sufficient period of time to preferentially adsorb ethylene over other impurities in the gas stream
Implementation Method 2
The product gas stream is removed by depressurization of the bed and desorption of ethylene adsorbed on the zeolite adsorbent with CDO framework
Data Source
AI summary
The present invention, and embodiments thereof, provide a process to separate ethylene products from impurities such as nitrogen, hydrogen, ethane, propane and isobutane without the need for distillation processes.