metallurgical heating furnace preheating device

Selection and installation of preheating device

The function of the preheater is to preheat the gas or air to a proper temperature by using the high temperature flue gas discharged from the furnace, so that when the gas and air enter the furnace for combustion, part of the physical heat will be brought in to save fuel and improve the theoretical combustion temperature. Air gas preheating device can be divided into heat exchange type and heat storage type. According to the different materials used, the heat exchanger can be divided into metal heat exchanger and ceramic heat exchanger.

Tubular metal heat exchanger, preheating air or gas to 300 to 400 ℃ or higher.

Needle shaped metal heat exchanger is suitable for medium and small heating furnace, heat treatment furnace and cupola with exhaust gas temperature of 700-1000 ℃.

Integral heat exchanger, radiation heat exchanger, ceramic heat exchanger

Ceramic heat exchanger regenerator generally uses various forms of brick lattice made of refractory materials as heat storage medium to complete the preheating process of air and gas. The regenerator materials for building regenerators are usually made of ordinary clayey soil. When the temperature is high, they can also be made of siliceous, high alumina or magnesite. In recent years, the regenerative furnace filled with fireball or honeycomb has developed rapidly. The preheating temperature of the regenerator is high, but the equipment is complex, the control links are many, and the technical requirements are high, so it is mostly used in large-scale high-temperature furnace.

There are many kinds of reversing devices used in the regenerator, which can be roughly divided into two types: the first type of reversing device is characterized by the same valve for the air gas inlet and the flue gas outlet, and the second type of reversing device is characterized by the separate gate valve for the air gas inlet and the flue gas outlet. The disadvantage of the former is that the air flow resistance is very large, and there is a short-circuit phenomenon between gas and exhaust gas during reversing. The disadvantage of the latter is that the operation is complex. In the design, the specific type and location of the reversing device should be selected according to the characteristics of the furnace and the advantages and disadvantages of various reversing devices..

Due to the intermittent working time of the regenerator, at least two regenerators should be set to work in turn to ensure the continuous preheating of the gas. Therefore, the reversing of regenerator is an indispensable operation.