Cryogenic Distillation Buffer Tank for Pressurization Flow Stability
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Solution Overview
Problem
Cryogenic air separation units face challenges in maintaining flow rates during pressurization phases, especially when producing argon, leading to increased compressor sizing needs and energy inefficiencies.
Innovation Solution
A system that includes a cryogenic liquid tank with a vaporizer and a capacity to manage flow by sending liquefied calorigenic gas to the vaporizer and vaporized liquid to columns during pressurization phases, allowing for flexible energy optimization and reduced compressor load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the main air compressor is sized to provide additional flow for cylinder pressurization, then the pressurization flow requirement is met, but the compressor size and cost increase
Solution Approach 1:
A buffer tank is introduced as an intermediary storage device between the compressor and the purification cylinders. The tank accumulates cold box feed gas during non-pressurization periods and releases it during pressurization phases, mediating the flow requirements and eliminating the need to size the compressor for peak pressurization demand.
Solution Approach 2:
The buffer tank is pre-filled with cold box feed gas during periods when the purification cylinders are not being pressurized. This preliminary accumulation of gas allows the system to meet sudden pressurization demands without requiring the compressor to be continuously oversized.
2Device complexity
If the compressor is sized for nominal flow rate without additional pressurization flow, then the compressor size is reduced, but the pressurization flow requirement is not met
Solution Approach 1:
The buffer tank acts as a mediator that decouples the compressor's continuous operation from the cyclic pressurization demands. It stores excess gas when demand is low and supplies gas when demand is high, allowing the compressor to be sized for average rather than peak demand.
3Power
If the cold box feed rate is reduced during pressurization phases, then the compressor load is reduced, but the column flow stability is compromised
Solution Approach 1:
The buffer tank mediates between the cold box feed rate and the column flow requirements. It absorbs the fluctuations in feed rate during pressurization phases and maintains a stable flow to the columns, preventing composition instability while allowing the compressor to operate at reduced load.
4Quantity of substance
If additional flow is specified on the main air compressor, then the pressurization demand is met, but the energy efficiency decreases
Solution Approach 1:
The buffer tank serves as an energy-smoothing intermediary that allows the compressor to operate at a lower, more efficient capacity. By storing gas during low-demand periods and releasing it during high-demand periods, the tank eliminates the need for continuous high-capacity compression, thereby improving overall energy 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 compensates for flow reductions without additional compressor flow, reducing costs, enhancing flexibility, and improving energy efficiency in air separation units, especially when producing argon.
Implementation Method 1
a tank vaporiser (R2)
Implementation Method 2
the gaseous mixture is condensed in a tank vaporizer of the capacity
Data Source
Figure 1
AI summary
The invention relates to a cryogenic distillation apparatus for a gas mixture (), including a purification apparatus (A) for purifying a gas mixture in a system with a plurality of adsorbant bottles, a column system (MP,LP,AR), a capacity (15), means for feeding a cryogenic liquid (19,V19,29,V29) to the capacity, means for feeding a vaporised liquid (2, V2) from the capacity to a column (MO) of the system, a vaporiser (R2) in the capacity for vaporising the contained liquid; means for feeding a calorigenic gas (4) to the vaporiser, and means for drawing a liquid (3) from the capacity.