PSA Air Prepurification at Lower Pressure for Cryogenic Separation
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Solution Overview
Problem
Cryogenic air separation processes face challenges in efficiently removing high boiling contaminants like H2O and CO2 at lower pressures, leading to increased costs and power consumption due to the need for complex and costly PSA prepurification systems designed for higher pressures.
Innovation Solution
A PSA prepurification system operating at pressures comparable to or below the highest common air pressure in the cryogenic separation unit, allowing for the division of air streams and subsequent compression to match the cryogenic separation unit's pressure, reducing power requirements and equipment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PSA prepurification systems are designed to operate at higher pressures, then contaminant removal efficiency is improved, but power consumption and equipment costs increase
Solution Approach 1:
The patent applies parameter changes by operating the PSA prepurification system at lower pressures (comparable to or below the highest common air pressure in the cryogenic separation unit) rather than at traditionally higher pressures. This pressure parameter change reduces the power consumption and thermodynamic penalties while maintaining effective contaminant removal through the adsorption process.
2Reliability
If PSA prepurification systems are designed to operate at higher pressures, then contaminant removal efficiency is improved, but equipment construction and transportation costs increase
Solution Approach 1:
The patent applies parameter changes by operating the PSA prepurification system at lower pressures (comparable to or below the highest common air pressure in the cryogenic separation unit) rather than at traditionally higher pressures. This pressure parameter change reduces the power consumption and thermodynamic penalties while maintaining effective contaminant removal through the adsorption process.
3Adaptability or versatility
If air streams are compressed to match cryogenic separation unit pressure, then system integration is improved, but power requirements increase
Solution Approach 1:
The patent applies inversion by reversing the traditional approach: instead of compressing air streams to match higher cryogenic separation unit pressure, the system operates the PSA prepurification at lower pressures comparable to the cryogenic unit's highest common air pressure. This eliminates the need for additional compression stages and reduces overall power requirements while maintaining system integration.
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 enables lower power consumption and reduced capital costs by facilitating liquid production flexibility and eliminating thermodynamic penalties associated with lower pressure operation, while maintaining efficient contaminant removal.
Implementation Method 1
PSA-based prepurification systems, there often exists the need to provide minor/auxiliary streams of air to the air distillation process
Implementation Method 2
In PSA-based prepurification systems, contaminant removal (such as H2O, CO2, C2H2, N2O) usually takes place at relatively constant temperature (e.g., 50-90° F.)
Implementation Method 3
at least a portion of the remaining air is further subjected to at least one stage of compression for subsequent use in the cryogenic separation unit
Implementation Method 4
Cryogenic distillation of air is the predominant source for the production of oxygen (O2) and nitrogen (N2)
Data Source
AI summary
The present invention relates to cryogenic air separation processes and systems that employ a pressure swing adsorption (PSA) prepurification process. It is advantageous to operate the PSA process at a pressure comparable to or below the operating pressure of the highest pressure column in the cryogenic separation unit. Following PSA prepurification, the air can be split into at least two fractions, with at least a portion of the air being directed to the cryogenic separation unit and at least a portion of the remaining air being further pressurized in at least one stage of compression.