Bubble-Column Condenser Staging for Heat Recovery Without Scale
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current seawater desalination technologies are energy- and capital-intensive, with inefficiencies in heat transfer and energy recovery, leading to high costs and environmental concerns due to the formation of hard scale on heat transfer equipment.
Innovation Solution
A multi-stage bubble-column vapor mixture condenser system that uses a carrier-gas stream to facilitate direct contact with a liquid bath, enabling efficient heat transfer and energy recovery through a counterflow arrangement, reducing thermal resistance and energy costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If reverse osmosis (RO) is used for seawater desalination, then the specific electricity requirement can be as low as 4 kWh/m³, but the system requires massive amounts of energy and capital investment
Solution Approach 1:
The desalination process is divided into multiple stages with intermediate heat recovery points. Each stage operates at different pressure and temperature conditions, allowing progressive concentration of brine and recovery of thermal energy at each step, thereby reducing total energy consumption while maintaining low specific electricity requirements
Solution Approach 2:
The system changes operating parameters (temperature, pressure, concentration) across different stages of the process. By varying these parameters and recovering energy at each transition point, the system achieves efficient desalination with reduced overall energy and capital requirements compared to single-stage RO
2Reliability
If thermal-energy-based multi-stage flash (MSF) distillation or multi-effect distillation (MED) is used, then desalination can be achieved, but the processes are energy- and capital-intensive
Solution Approach 1:
The system incorporates feedback loops where thermal energy from later stages is fed back to earlier stages. This internal heat recovery mechanism reduces external energy input requirements while maintaining reliable desalination capability, addressing both the reliability and energy intensity concerns
3Productivity
If MSF and MED systems operate at high temperatures, then desalination efficiency improves, but calcium sulphate precipitation forms hard scale on heat transfer equipment
Solution Approach 1:
The concentration process is segmented into multiple stages with progressively increasing brine concentration. Each stage operates at optimized temperature and pressure conditions that prevent calcium sulphate saturation, thereby maintaining high desalination efficiency without hard scale formation on heat transfer surfaces
Solution Approach 2:
The system dynamically adjusts operating parameters (temperature, pressure, residence time) at each stage to keep calcium sulphate below its precipitation point while maximizing water production. This parameter optimization allows high productivity without the harmful scale formation effect
4Reliability
If a standard indirect contact dehumidifier is used, then the dehumidification function is provided, but thermal resistance from incondensable gases reduces heat transfer rates
Solution Approach 1:
The system uses a specially designed heat transfer medium that facilitates direct contact between the vapor mixture and condensing surfaces. This intermediary approach eliminates the thermal resistance barrier created by incondensable gases in indirect contact systems, significantly improving heat transfer rates while maintaining reliable dehumidification
Solution Approach 2:
The patent replaces the mechanical indirect contact heat transfer system with a direct contact or enhanced heat transfer mechanism. This substitution eliminates the thermal resistance issue inherent in indirect contact dehumidifiers, achieving both high heat transfer rates and reliable dehumidification function
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 achieves a significantly higher heat-transfer coefficient, reducing energy costs and overall system costs by maintaining high energy recovery and minimizing equipment costs, while avoiding the formation of hard scale.
Implementation Method 1
uses a carrier-gas stream to facilitate direct contact with a liquid bath, enabling efficient heat transfer
Implementation Method 2
enabling efficient heat transfer and energy recovery through a counterflow arrangement
Implementation Method 3
Bubble-column vapor mixture condenser
Implementation Method 4
enabling efficient heat transfer and energy recovery
Implementation Method 5
enabling efficient heat transfer and energy recovery through a counterflow arrangement, reducing thermal resistance
Data Source
Figure 1~2
Figure 3~4
Figure 5
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 coolant 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.