Role of Drift eliminators in Cooling tower
Drift Eliminators are a critical, yet often overlooked, component in a cooling tower. Their primary role is economic and environmental: to minimize water loss and prevent pollution.
Here’s a detailed breakdown of their role, function, and importance.
Primary Role: Capture Water Droplets
The core function of a drift eliminator is to capture and return entrained water droplets from the air stream exiting the tower before they are blown into the atmosphere.
- “Drift” refers to these tiny liquid water droplets (not vapor) that are carried out of the tower by the exiting air.
- These droplets are same chemical composition as the circulating cooling water, which often contains treatment chemicals, minerals, and contaminants.
Key Functions & Why They Matter
1. Conserve Water & Reduce Operating Costs
- Drift represents a direct loss of expensive, treated water.
- Make-up water must continuously replace this loss. By minimizing drift, operational costs for water and chemicals are significantly reduced.
2. Protect the Environment & Surroundings
This is arguably their most important function.
- Prevent Chemical Pollution: Cooling tower water contains corrosion inhibitors (e.g., zinc), scale inhibitors (e.g., phosphates), biocides (e.g., chlorine, bromine), and other treatment chemicals. Drift deposits these chemicals onto the ground, vegetation, and structures.
- Prevent Salt & Mineral Deposition: The concentrated dissolved solids (TDS) in the water can damage paint, corrode metal structures, and harm plants.
- Mitigate Health Risks: In rare cases, drift can contribute to the spread of certain bacteria if not properly managed (a secondary benefit of containing water).
Maintain System Water Balance
- Uncontrolled drift loss makes it difficult to manage the cycles of concentration (how many times minerals are concentrated in the water), which is key for controlling scale and corrosion.
4. Improve Neighbor Relations
- Drift can create a visible “fog” or salty, wet mist downwind, damaging property and creating a nuisance. Eliminators help prevent this.