Combustion With Preheated Air Introduction

A substantial amount of heat is wasted in the exhaust from industrial furnaces. Flue loss can be easily reduced by transferring some of this waste heat from exhaust gas to combustion air. There are two basic types of heat exchangers for this purpose: recuperators and regenerators. Nearly all non-premixed burner systems are now capable of using preheated combustion air. There are a wide variety of air preheaters now available, with the standard of the last decade being metallic recuperators capable of producing air temperatures from 800 to 1000 degrees F. Recent innovations in heat exchanger technology have brought out a new breed of heat exchangers capable of heating air to almost 2000 degrees F. These high temperatures severely burden combustion equipment and new burners must accompany these advanced heat exchanger technologies. The papers in this session report on research, dev~lopment and application experience with high temperature burners and high efficiency heat exchangers. Two presentations concern the innovative regenerative burner technology, while the others explain how to avoid fuel decomposition in burner tubes in this high temperature environment and how to apply recuperation in radiant tubes