PI: Julio Bravo
Co-PI: Carlos Romero
University: Lehigh University
Industry partner: Air Products and Chemicals, Inc.
This proposal outlines a 12-month project to advance and demonstrate a drying system that removes moisture from wet solid fuels by bringing the fuel into direct contact with hot flue gas. The project centers on a process designed to produce a drier, more stable fuel that burns better, delivers more usable heat, and supports efficient operation of boilers and gasifiers. The system relies on heat already present in flue gas from existing equipment, rather than adding new fuel or extra energy. Because flue gas is made mostly of inert gases with only small amounts of oxygen, it can safely contact the fuel during drying while reducing fire and reaction risks.
The project will focus on the operation and performance of the dryer, which is a vertical vessel where wet fuel enters from the top and forms a packed fuel bed. Hot flue gas is divided into primary and secondary streams. The primary stream flows through a wrap-around duct, enters a plenum at the bottom, and moves upward through the fuel bed, heating the particles and evaporating moisture. The wrap-around duct keeps the walls warm, prevents condensation, and supports steady heat transfer. The secondary stream travels through hollow screw shafts that move nearly dried fuel from the vessel, providing the final drying step before the fuel exits.
Over the 12-month period, the project will focus on demonstrating the concept and optimizing operating conditions for efficient drying operation. The goal is to see how these changes affect how well the dryer works and to identify the operating settings for different fuel and flue gas conditions.