Discover Top Posts Tagged with #cavt

Top Performance Testing for Power Plants - Tefugen

Introduction:

Performance Testing ensures that the plant operates according to its intended functionality and guaranteed parameters. It maximizes plant efficiency, reduces emissions, and minimizes operating costs by identifying any inefficiencies or capacity limitations and providing recommendations for recovery and performance improvement.

Cold Air Velocity Test (CAVT):

In boilers, the flue gas flow pattern in the second pass may lack uniformity due to combustion behavior, fouling tendencies, and configurations such as Gooseneck. This non-uniformity leads to uneven heat transfer in tube bundles and erosion of tube bundles in high-velocity zones. CAVT is conducted to assess the flue gas flow pattern by mapping the velocities measured across the top planes of different crosssections in the Boiler's second pass and the coefficient of variation (COV) in velocity is calculated to access the condition of the flow pattern.

Clean Air Flow Test (CAFT):

CAFT is performed as per the ASME-PTC 4.2 standard and it is performed in Coal Pulverizers outlet coal pipes by supplying only air as medium. In a variable orifice system, the velocity deviation among the pulverizers outlet coal pipes will be determined and an adjustment will be done in the orifice to restrict the deviations to the allowable limit. In a fixed orifice system, it ensures the correct orifice sizes are installed.

Dirty Air Flow Test (DAFT) and Iso Kinetic Sampling:

DAFT is carried out in Coal Pulverizers outlet coal pipes by following the ASME-PTC 4.2 standard in the presence of coal & air mixture inside the coal pipes.This test ensures the correct orifice sizes are installed in the case of a fixed orifice system. In the case of a variable orifice system, the velocity deviation among the pulverizer outlet coal pipes will be measured and an adjustment will be made to ensure the velocity deviations are within the allowable limit. Iso Kinetic Sampling systematically analyzes coal fineness.

Air and Gas Flow Test:

This testing measures the flow and velocity profiles in various streams of the boiler's air and gas circuits. Evaluating velocity profiles and pressure drops at different locations will show the current condition of the flow. Corrections can be made using CFD analysis to equalize flow and enhance system performance.

Air Pre Heater (APH) Performance Test:

APH performance testing, following the ASME-PTC 4.3 standard. Air leakage, pressure drop, temperature rise in air and temperature drop in flue gas will be identified. This test reveals the current condition of the APH which includes choking, seal surface clearances, and the effectiveness of the sealing system.

Flue Gas Analysis Test (NOx & SOx):

This test assesses the levels of oxides of nitrogen (NOx) and oxides of sulfur (SOx) emissions resulting from coal combustion. It ensures compliance with emission norms by evaluating the conversion of bound nitrogen and sulfur in coal.

Gas Distribution (GD) Test:

GD test is conducted as per the ICAC-EP-7 standard in electrostatic precipitator (ESP) to ensure uniform flow distribution across the ESP's cross-section. Over time, operating the boiler may disturb or erode guide vanes, flow splitters, etc., resulting in non-uniform flow distribution and increased emissions. The flow pattern will be assessed by calculating the coefficient of variation (COV) in velocity.

#testing #performance testing #cavt #daft #air flow duct