Cryogenic Oxygen Production with an Auxiliary Column for Higher Capacity
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Solution Overview
Problem
The existing cryogenic air separation plants face limitations in oxygen production capacity due to maximum vessel diameter constraints and the need for multiple parallel units, leading to increased construction costs and reduced economies of scale.
Innovation Solution
The integration of an auxiliary column operating at the same pressure as the lower pressure columns, which rectifies impure oxygen streams to produce oxygen-rich streams with lower nitrogen content, reducing vapor loadings in the nitrogen rectification sections and increasing plant capacity by 25-30%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple parallel air separation plants are constructed to exceed 5000 metric tons per day oxygen production capacity, then the oxygen production capacity is improved, but the construction cost increases and economies of scale are reduced
Solution Approach 1:
The patent combines multiple air separation units into a single integrated plant with shared infrastructure. Multiple higher pressure columns feed into a common lower pressure column, merging previously separate functions into one coordinated system. This integration allows the plant to achieve over 5000 metric tons per day capacity while avoiding the need for multiple independent plant enclaves, thereby reducing construction costs and maintaining economies of scale.
Solution Approach 2:
The lower pressure column serves multiple functions by receiving feed from multiple higher pressure columns simultaneously. It acts as a common processing unit that handles oxygen production for the entire integrated plant, rather than each unit having its own dedicated lower pressure column. This multi-functionality reduces the total number of columns and associated infrastructure needed.
2Productivity
If the lower pressure column diameter is increased to handle higher vapor loadings, then the oxygen production capacity is improved, but the construction cost and installation difficulty increase due to maximum vessel diameter limitations
Solution Approach 1:
The patent segments the air separation process into multiple higher pressure columns that operate in parallel, each handling a portion of the total feed. These segmented units feed into a single lower pressure column, distributing the vapor loading across multiple entry points rather than requiring one excessively large column. This segmentation allows the lower pressure column to maintain a practical diameter while still achieving high overall plant capacity.
3Productivity
If multiple parallel air separation units are employed within an enclave, then the oxygen production capacity is improved, but the construction cost increases due to repeated column shell construction
Solution Approach 1:
The patent merges multiple air separation units into a single integrated plant configuration. Instead of constructing separate column shells for each unit, the design uses shared infrastructure including a common lower pressure column, unified balance of plant equipment, and consolidated foundation structures. This merging approach maintains high production capacity while significantly reducing the number of column shells that must be manufactured and installed.
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 increased oxygen production within a multiple plant installation, potentially eliminating the need for an additional plant and reducing construction costs by optimizing capacity utilization.
Implementation Method 1
The at least one impure oxygen stream is rectified within the auxiliary column to form an oxygen containing liquid as a column bottoms and an auxiliary column nitrogen-rich vapor column overhead
Implementation Method 2
The compressed and purified air, which in certain plants can be further compressed, is cooled to a temperature suitable for its rectification
Data Source
AI summary
A method and apparatus for producing an oxygen product in which air is separated in an installation including air separation units having higher and lower pressure columns. A pumped liquid stream generated within the installation, that can be a pumped liquid oxygen stream, is warmed within a main heat exchanger through indirect heat exchange with a compressed air stream to produce a liquid air stream. An impure oxygen stream is rectified within an auxiliary column to produce an oxygen containing stream that is introduced into the lower pressure column of each of the air separation units and intermediate liquid streams, composed of the liquid air stream or another air-like stream, reflux the lower pressure columns and the auxiliary column and optionally the higher pressure column of each of the air separation units.