Heat Exchanger Lifting Force Control via Heavy Gas Injection
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Solution Overview
Problem
Heat exchangers operating with vertical two-phase flow face challenges in maintaining sufficient lifting force for the liquid phase, leading to inefficient operation, mechanical damage, and potential breakdowns, due to constraints like pressure drop and compressor limitations.
Innovation Solution
A method and control unit that evaluate the lifting force by analyzing the time derivative of hot end approach and pressure drop, adjusting operating parameters such as gas flow rate and inlet temperatures to ensure a sufficient lifting ratio, and implementing measures to prevent interruptions and equipment wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the flow rate of the gas phase is increased to obtain sufficient lifting force, then the lifting force increases, but the pressure drop increases and compressor limitations are exceeded
Solution Approach 1:
The patent changes the parameter of gas phase composition by introducing a heavy gas with high molar mass into the gas phase. This increases the density and lifting force of the gas phase without requiring an increase in flow rate, thereby avoiding excessive pressure drop and compressor limitations while still achieving sufficient lifting force for the liquid phase
Solution Approach 2:
Instead of solving the lifting force problem by increasing flow rate (one dimension), the patent introduces a new dimension by changing the compositional properties of the gas phase through heavy gas addition. This alternative approach path allows achieving the same lifting effect through a different physical mechanism
2Force
If the temperature of the fluid is increased to obtain sufficient lifting force, then the lifting force increases, but the efficiency decreases
Solution Approach 1:
The patent changes the parameter of gas phase composition by adding heavy gas with high molar mass, which increases the lifting force through increased density rather than through temperature increase. This avoids the energy losses associated with high temperature operation while still achieving sufficient lifting force
3Reliability
If the gas flow rate is reduced to maintain compressor limitations, then the pressure drop decreases, but the lifting force becomes insufficient
Solution Approach 1:
The patent changes the compositional parameter of the gas phase by introducing heavy gas with high molar mass. This increases the gas density and lifting force per unit flow rate, allowing the system to maintain sufficient lifting force at reduced gas flow rates that comply with compressor limitations
Solution Approach 2:
The patent implements a control system that monitors the lifting force and adjusts the composition and flow rate of the gas phase in real-time. This feedback mechanism ensures that the lifting force remains sufficient while operating within compressor limitations by dynamically optimizing the gas phase parameters
4Reliability
If operating parameters are not optimized, then the heat exchanger may operate with insufficient lifting force, but optimizing parameters requires complex evaluation and control
Solution Approach 1:
The patent implements a control system that continuously monitors operating parameters such as pressure drop, flow rates, and temperature, and uses this feedback to automatically adjust gas phase composition and flow rate to maintain optimal lifting force, thereby ensuring reliable operation without requiring complex manual intervention
Solution Approach 2:
The control system automatically evaluates and adjusts operating parameters to maintain sufficient lifting force without requiring external intervention. The system self-regulates by monitoring its own performance parameters and making necessary adjustments to gas phase composition and flow rate
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 optimizes the efficiency of the heat exchanger, reduces wear, and prevents breakdowns by ensuring a sufficient lifting force, thereby improving the overall operation and extending equipment lifespan.
Implementation Method 1
on each droplet of the liquid phase the aerodynamic lifting force must be greater than the gravitational force or if the droplet is in contact with the wall greater than the sum of the gravitational force and the frictional force of the wall
Implementation Method 2
a heat exchanger area transferring heat from the second fluid to the first fluid
Data Source
Figure 1
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AI summary
A method and a control unit for evaluating lifting force of a gas phase of a substantially vertical upward two-phase flow of a first fluid in a heat exchanger. The first fluid comprises the gas phase and a liquid phase. The method comprises determining that the lifting force of the gas phase is insufficient for lifting the liquid phase based on hot end approach of the heat exchanger and/or on pressure drop of the first fluid over the heat exchanger. The control unit is configured to determine that the lifting force of the gas phase is insufficient for lifting the liquid phase based on hot end approach of the heat exchanger and/or on pressure drop of the first fluid over the heat exchanger. A heat exchanger assembly comprising a heat exchanger and the control unit.