Posts

SEALS AND LEAKAGE OF AIR PREHEATER

Image
2. Thermal turndown.  The typical APH may be as much as 60 feet in diameter. When the APH rotor is heated from a cold condition (blue), thermal expansion (yellow) can cause the rotor to droop or “turn down” up to 3 inches on the periphery. Knowing the amount of turndown is important when presetting the seal position before operation, because seal positions will change as the rotor warms to its operating temperature.  Source: Storm Technologies Inc. 1. Circumferential leakage through an APH.  The left blue line represents the bypass seal leakage around the air preheater into the warm airflow. The bottom blue line represents the bypass seal leakage (also called peripheral seals) passing the axial seals into the gas path. The red line on the right represents the bypass seal leakage passing around the air preheater (APH) into the cold gas flow. The top yellow arrows represent the hot radial seal leakage, while the bottom yellow arrows represent the cold radial seal leakage.  Courtesy:
Post a Comment
Read more

AIR PREHEATER

Image
Introduction on Air preheater An  air preheater  (APH) is any device designed to heat  air  before another process (for example,  combustion  in a  boiler ) with the primary objective of increasing the thermal efficiency of the process. They may be used alone or to replace a  recuperative  heat system or to replace a steam coil. In particular, this article describes the combustion air preheaters used in large  boilers  found in  thermal power stations  producing  electric power  from e.g.  fossil fuels ,  biomass  or  waste. For instance, as the  Ljungström air preheater  has been attributed worldwide  fuel savings  estimated to 4,960,000,000  tons  of  oil , "few inventions have been as successful in saving fuel as the Ljungström Air Preheater", marked as the 44th  International Historic Mechanical Engineering Landmark  by the  American Society of Mechanical Engineers . The purpose of the air preheater is to recover the heat from the boiler  flue gas  which incr
Post a Comment
Read more