Best device for removing very fine particulates from power station flue gas In large thermal power plants, which equipment is preferred for high-efficiency removal of fine fly ash from flue gases?

Introduction / Context: Controlling particulate emissions from coal-fired and similar thermal power stations is crucial for air quality compliance. Flue gas contains a broad particle size distribution, with significant fractions in the fine (sub-micron to a few microns) range, often called fly ash. The question focuses on the most common, highly efficient industrial choice for large-scale fine particulate control.

Given Data / Assumptions:

• Large, continuous-duty thermal power station service.
• Target: very fine particulates (fly ash) at high flow rates and temperatures.
• Need: proven, high-collection efficiency with acceptable pressure drop and operability.

Concept / Approach: Electrostatic precipitators (ESPs) charge particles using corona discharge and then collect them on oppositely charged plates. ESPs can achieve very high collection efficiencies (often exceeding 99%) for a wide size range, with relatively low pressure drop—making them a mainstay in power generation. While fabric filters (baghouses) can also achieve excellent fine-particle removal, ESPs have historically been the default in many large units due to thermal tolerance, capacity, and low pressure losses.

Step-by-Step Solution:

Verification / Alternative check: Regulatory performance reports and plant configurations around the world corroborate ESP use for fine ash control in large boilers.

Why Other Options Are Wrong:

Common Pitfalls: Equating all “filters” with best fine capture regardless of scale; process constraints and pressure drop matter in utility service.

Final Answer: Electrostatic precipitators