A Cottrell (electrostatic) precipitator removes particulate matter from gas streams primarily by using which phenomenon?

Introduction / Context:
Electrostatic precipitators (often called Cottrell precipitators) are standard equipment for cleaning dusty flue gases in power, cement, and metallurgical industries. Understanding the underlying charging and collection mechanism is essential for design and troubleshooting.

Given Data / Assumptions:

• Gas contains fine particulates requiring high collection efficiency.
• High-voltage discharge electrodes and grounded collection plates are present.

Concept / Approach:
Corona discharge is a non-thermal electrical discharge generated at sharp electrodes under high voltage. It creates a cloud of ions that charge particulates as they pass the electrostatic field. Charged particles then drift to oppositely charged or grounded plates under Coulombic forces and are removed by rapping.

Step-by-Step Solution:

Verification / Alternative check:
Performance formulas include migration velocity proportional to electric field and particle charge acquired in the corona region, confirming the role of corona rather than spark breakdown.

Why Other Options Are Wrong:

Common Pitfalls:
Confusing corona with arcing; assuming alternating current alone ensures collection without ion generation.

Final Answer:
Corona discharge with high-voltage electrodes