Multi-Stage Bubble-Column Condenser for Energy-Recovering Heat Transfer
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Solution Overview
Problem
Current seawater desalination technologies are energy- and capital-intensive, with high energy costs due to inefficiencies in heat transfer and energy recovery, particularly due to the presence of incondensable gases which increase thermal resistance and reduce heat-transfer coefficients.
Innovation Solution
The use of multi-stage bubble-column vapor mixture condensers with direct contact between the carrier gas and liquid in each stage, optimizing heat transfer and energy recovery through a novel multi-staging technique, reducing energy and equipment costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If direct-contact condenser is used to reduce thermal resistance, then heat transfer rates increase, but energy efficiency decreases
Solution Approach 1:
The condenser is divided into multiple stages with intermediate heat exchangers that recover energy at each stage. The multi-stage configuration segments the heat transfer process, allowing energy recovery between stages while maintaining high heat transfer rates through direct contact in each segment.
Solution Approach 2:
Energy recovered from the condensing vapor is fed back through heat exchangers to preheat the incoming feed water or seawater. This feedback mechanism reduces the overall energy input required while maintaining high productivity through continuous direct-contact heat transfer.
2Productivity
If multi-stage bubble-column condenser with direct contact is used, then heat-transfer coefficient increases, but device complexity increases
Solution Approach 1:
The complex heat transfer process is segmented into multiple simpler stages, each using straightforward direct-contact bubble column geometry. This segmentation achieves high overall heat-transfer coefficients while keeping each individual stage structurally simple and easy to construct.
Solution Approach 2:
The bubble-column design allows the vapor-gas mixture to naturally bubble through the liquid condensate without complex mechanical agitation or pumping systems. The system uses the inherent buoyancy and phase change dynamics to drive the heat transfer process, reducing mechanical complexity.
3Loss of energy
If conventional indirect contact dehumidifier is used, then energy efficiency is maintained, but heat transfer rates are limited by thermal resistance
Solution Approach 1:
The patent introduces an intermediary direct-contact heat transfer mechanism that bridges the gap between energy efficiency and heat transfer rate. By using the condensing vapor itself as the heat transfer medium in direct contact with the liquid, the system achieves high heat transfer coefficients while incorporating energy recovery systems to maintain overall 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 achieves a significantly higher heat-transfer coefficient, enabling efficient separation of pure water from seawater with reduced overall costs and energy consumption, comparable to film condensation of steam.
Implementation Method 1
The condensable fluid in liquid phase fills the chambers of the first stage and the second stage such that the carrier-gas stream passes through in direct contact with the liquid
Implementation Method 2
optimizing heat transfer and energy recovery through a novel multi-staging technique
Data Source
AI summary
In a bubble-column vapor mixture condenser, a fluid source supplies a carrier-gas stream including a condensable fluid in vapor phase. The condensable fluid in liquid form is contained as a bath in a chamber in each stage of the condenser, and the carrier gas is bubbled through the bath to condense the fluid into the bath. Energy from condensation is recovered to a liquid composition in a conduit that passes through the liquid in the stages of the condenser. The bubble-column vapor mixture condenser can be used, e.g., in a humidification-dehumidification system for purifying a liquid, such as water.