Bubble Column Condenser Staging for Non-Condensable Gas Removal
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Solution Overview
Problem
Current desalination methods, such as HDH processes, face inefficiencies due to the presence of non-condensable gases, which reduce heat and mass transfer rates and increase energy consumption in condensers.
Innovation Solution
The use of bubble column condensers with a vapor distribution region and multiple stages to efficiently remove water vapor from humidifier outlet streams, enhancing heat and mass transfer while minimizing energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a carrier gas is used in HDH systems, then the humidification process can be achieved, but the presence of non-condensable gas reduces heat and mass transfer rates in the condenser
Solution Approach 1:
The condenser is divided into multiple stages with intermediate gas outlets. Each stage processes a portion of the vapor-gas mixture, allowing progressive condensation and removal of non-condensable gases at intermediate points, thereby maintaining high heat and mass transfer rates throughout the system.
Solution Approach 2:
Non-condensable gases are extracted from the vapor-gas mixture at intermediate locations in the condenser. This removal prevents the accumulation of non-condensable gases that would otherwise increase thermal resistance and reduce condensation effectiveness, while still allowing the carrier gas to fulfill its humidification function.
2Ease of operation
If non-condensable gas is present in the condensing stream, then the HDH process can operate, but thermal resistance to condensation increases
Solution Approach 1:
A liquid layer is introduced as an intermediary medium between the vapor-gas mixture and the condenser walls. This liquid layer facilitates heat and mass transfer by providing a continuous phase for condensation, reducing the thermal resistance caused by non-condensable gases while maintaining effective condensation operation.
Solution Approach 2:
Non-condensable gases are continuously extracted at intermediate locations, preventing their accumulation and the associated increase in thermal resistance. This extraction mechanism maintains condensation effectiveness while allowing the HDH process to operate with carrier gas.
3Device complexity
If conventional condensers are used, then the system structure is simple, but power consumption increases
Solution Approach 1:
The condenser is segmented into multiple stages with intermediate gas outlets and liquid injection points. This segmentation improves energy efficiency by enabling progressive condensation and heat recovery, reducing overall power consumption while maintaining a relatively simple overall system structure that builds on conventional condenser designs.
Solution Approach 2:
The multi-stage condenser with intermediate liquid injection maintains continuous condensation action throughout the vapor-gas mixture flow path. This continuous useful action improves energy efficiency by preventing idle zones and ensuring consistent heat and mass transfer, thereby reducing power consumption compared to conventional single-stage condensers.
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 improves heat and mass transfer rates, reduces energy consumption, and increases the effectiveness of desalination systems by effectively handling non-condensable gases, leading to more efficient water purification.
Implementation Method 1
the bubble column condenser is configured to remove at least a portion of the water vapor from the humidifier outlet stream to produce a condenser gas outlet stream lean in water relative to the humidifier outlet stream and a condenser water outlet stream
Implementation Method 2
a heat exchanger separate from the bubble column condenser and fluidically connected to the condenser water outlet and configured to remove heat from the condenser water outlet stream
Data Source
AI summary
Condensing apparatuses and their use in various heat and mass exchange systems are generally described. The condensing apparatuses, such as bubble column condensers, may employ a heat exchanger positioned external to the condensing vessel to remove heat from a bubble column condenser outlet stream to produce a heat exchanger outlet stream. In certain cases, the condensing apparatus may also include a cooling device positioned external to the vessel configured and positioned to remove heat from the heat exchanger outlet stream to produce a cooling device outlet stream. The condensing apparatus may be configured to include various internal features, such as a vapor distribution region and/or a plurality of liquid flow control weirs and/or chambers within the apparatus having an aspect ratio of at least 1.5. A condensing apparatus may be coupled with a humidifier to form part of a desalination system, in certain cases.