In the previous article, we discussed the working principles, advantages, and disadvantages of atmospheric condensers with circulating water as well as indirect condensers with circulating water. Today, we will focus on the patented product — the evaporative condenser, and conduct an in-depth analysis of how it helps the final effect of the multi-effect evaporator form a vacuum and realize the condensation of secondary steam.
The key to the formation of vacuum in the final effect
In a multi-effect evaporator system, the condensation of the secondary steam in the final effect is the core link in creating a vacuum environment. Whether it is an atmospheric condenser or an indirect condenser, their core purpose is to cause the secondary steam to undergo phase change and liquefaction through cooling, thereby reducing the pressure in the final effect and maintaining the degree of vacuum. As a patented technology product, the evaporative condenser features a unique design concept and working logic.
Analysis of the "Three-Stage" Structure of the Evaporative Condenser
The structure of the evaporative condenser can be divided into three core parts, each performing its own function while collaborating closely:
? Upper part: Induced draft fan / Exhaust fan
It is responsible for driving air flow and providing power support for heat exchange.
? Middle part: Heat exchanger
As the core heat exchange area, it serves as a key carrier for heat exchange between the final-effect secondary steam and the external environment.
? Lower part: Water tank
It is used to store spray water and continuously provide cooling water sources for the heat exchanger.
These three parts work in synergy, forming an efficient "condensation - heat dissipation" closed-loop system.
Core working principle: The clever coordination between phase-change heat absorption and heat balance
The working process of the evaporative condenser essentially relies on the phase change characteristics of air and water to achieve heat transfer, ultimately condensing the final-effect secondary steam into water and thereby forming a vacuum. The specific process consists of the following key steps:
Introduction of final-effect steam
The secondary steam generated in the final effect of the multi-effect evaporator is introduced into the tube side (i.e., the internal channels of the heat exchanger) of the evaporative condenser through pipelines. At this point, the steam is in a state ready for condensation, and the phase change from vapor to liquid will release heat.
Synergistic effect of spray water and air
3. Phase-change heat absorption: Taking away the heat released by the steam
When unsaturated air comes into contact with the spray water, the water will evaporate rapidly (undergo phase change), a process that requires absorbing a large amount of heat. This part of the heat exactly comes from the heat released by the condensation of the secondary steam in the tube side, and the two form a perfect heat balance:
? Inside the tube side: The secondary steam releases heat and condenses, changing from a vapor state to a liquid state, with a sudden reduction in volume, thus forming a vacuum.
? Outside the shell side: The water evaporates and absorbs heat, and the air becomes saturated and is discharged by the induced draft fan.
"Reutilization" of saturated air
Even if high-humidity air is introduced (such as 98% or even 100% saturated air), when it flows through the heat exchanger, it will be heated by the heat inside the tube side. After the temperature rises, it becomes unsaturated air, regaining the ability to absorb moisture (and thus absorb heat through evaporation), ensuring the continuous and efficient operation of the condensation process.
Key design principle: Adapt to local conditions and match the local meteorological conditions
The performance of the evaporative condenser is not fixed, and its design must be closely integrated with the meteorological data of the application scenario:
? Air humidity and temperature: The air parameters in different regions (such as the dry north and humid south) vary significantly, which directly affects the efficiency of water evaporation and heat exchange capacity.
? Customized parameters: Core parameters such as air volume and heat exchange area need to be calculated based on local humidity and temperature, avoiding the misunderstanding of "one-size-fits-all for both north and south". For example, if the equipment parameters suitable for the north are directly applied to the high-humidity south, it may lead to insufficient condensation efficiency.
Therefore, every evaporative condenser is a product of "tailor-made" design, which requires precise meteorological data simulation and engineering calculations.
Summary: Core advantages of the evaporative condenser
The evaporative condenser cleverly utilizes the phase change balance between "heat absorption by water evaporation" and "heat release by steam condensation" to achieve an efficient vacuum formation mechanism, while also possessing the flexibility to adapt to different environments. Its core logic can be summarized as: using air as the carrier, water evaporation as the medium, and achieving precise heat transfer through customized design.
In the next episode, we will further explore the comparative advantages of evaporative condensers over traditional condensers, as well as their application cases in actual industrial scenarios. If you still have questions about the working principle of evaporative condensers, please feel free to consult and communicate with us!
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