Argon Reflux Condensation with Crude Oxygen Flow Control
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Solution Overview
Problem
The existing method of using once-through heat exchangers to condense argon-rich vapor in air separation units faces challenges with dry out and flammability hazards due to high boiling temperature hydrocarbons freezing and concentrating, leading to control issues with crude liquid oxygen flow rates.
Innovation Solution
A system comprising a plurality of once-through heat exchangers connected to an argon column, a phase separator, and flow control mechanisms to manage the crude liquid oxygen flow rates proportionally to vaporization surface areas, ensuring efficient condensation and preventing dry out by controlling the flow rates and temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If once-through heat exchangers are used to condense argon-rich vapor, then device complexity is reduced and cost is lowered, but dry out occurs and flammability hazards arise due to hydrocarbon concentration
Solution Approach 1:
The system employs flow controllers that continuously monitor and adjust the flow rates of crude liquid oxygen to each heat exchanger based on vaporization surface area requirements. This feedback mechanism ensures adequate liquid flow is maintained in all heat exchangers, preventing dry out conditions that would lead to hydrocarbon concentration and flammability hazards, while still utilizing the simpler once-through heat exchanger design.
Solution Approach 2:
The invention changes the operational parameters by controlling flow rates as a function of vaporization surface area. By adjusting flow rates dynamically based on heat exchanger size and operating conditions, the system maintains safe liquid levels in all heat exchangers, preventing the harmful concentration of hydrocarbons while preserving the cost-effective once-through design.
2Ease of operation
If crude liquid oxygen flow rates are not controlled, then ease of operation is improved, but dry out occurs leading to hydrocarbon freezing and flammability hazards
Solution Approach 1:
The system achieves self-service operation through automated flow controllers that independently regulate crude liquid oxygen flow to each heat exchanger based on pre-programmed vaporization surface area parameters. The system self-adjusts to maintain safe operating conditions without requiring manual intervention, thereby ensuring reliability while maintaining ease of operation.
Solution Approach 2:
The invention replaces manual mechanical flow control with automated electronic flow controllers. This substitution maintains ease of operation through automated control while significantly improving reliability by preventing dry out conditions and associated flammability hazards through consistent, precise flow rate management.
3Loss of energy
If heat exchangers are sited at high level to reduce head loss, then energy efficiency is improved, but control of liquid flow becomes problematical due to flashing
Solution Approach 1:
The system uses flow controllers with feedback mechanisms that monitor and adjust crude liquid oxygen flow rates to compensate for the effects of high elevation placement. By continuously regulating flow based on vaporization surface area requirements, the system maintains proper liquid levels in heat exchangers even at high elevations, preventing flashing while preserving the energy efficiency benefits of reduced head loss.
Solution Approach 2:
The invention addresses the high elevation challenge by changing the control parameter from manual flow adjustment to automated flow rate control based on vaporization surface area. This parameter change enables the system to operate efficiently at high elevations with minimal head loss while maintaining safe liquid levels and preventing flashing through precise electronic control.
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 system effectively condenses argon-rich vapor, maintains stable flow rates, and prevents dry out in the heat exchangers, reducing the risk of flammability hazards and ensuring efficient operation of the air separation unit.
Implementation Method 1
the argon-rich vapor column overhead is condensed in a plurality of once-through heat exchangers through indirect heat exchange with a crude liquid oxygen column bottoms
Implementation Method 2
argon-rich vapor streams are condensed within condensation passages of the once-through heat exchangers to produce an argon-rich liquid product stream
Implementation Method 3
a stream of the crude liquid oxygen column bottoms is in turn further refined in the lower pressure column... the crude liquid oxygen is introduced into the shell and is partially vaporized through indirect heat exchange with the argon-rich vapor
Data Source
AI summary
An argon reflux condensation system and method in which a plurality of once-through condensers are connected to an argon column of an air separation plant to condense argon-rich vapor streams for production of reflux to the argon column. Condensation of the argon-rich vapor streams is brought about through indirect heat exchange with crude liquid oxygen streams that partially vaporize and are introduced into a lower pressure column of the plant for further refinement. The flow rate of the crude liquid oxygen streams are sensed and controlled at locations in the air separation plant where the crude liquid oxygen is in a liquid state and in proportion to the size of the once-through heat exchangers. Prior to flowing into the once-through condensers, the partially vaporized crude oxygen stream enters a phase separator which separates the crude oxygen vapor from the crude liquid oxygen. The separated crude oxygen vapor bypasses the once-through condensers and is mixed with the vaporized oxygen stream that exits the one-through condensers. Feed stream flow rate to the argon column is controlled in response to air flow rate to the plant and product flow rate is controlled in response to the feed stream flow rate to the argon column.