What Is The Difference Between Flue Type Waste Heat Boiler And Shell And Tube Waste Heat Boiler

What Is The Difference Between Flue Type Waste Heat Boiler And Shell And Tube Waste Heat Boiler?

Both flue-type waste heat boiler and shell-and-tube waste heat boiler are waste heat boilers. The former is a boiler, and the latter is a pressure vessel.

(1) Flue-type waste heat boiler: a water-tube waste heat boiler whose tube bundle is set in a furnace made of refractory materials. The structure is very similar to that of a general combustion boiler. High-temperature gas passes through the furnace (or flue), and the tube bundle The steam is generated by indirect heat exchange with water, and the steam-water mixture rises along the tube bundle and enters the upper and lower steam drums. After the steam is separated, the water enters the lower steam drum along the unheated downcomer again, forming a natural circulation.

(2) Shell-and-tube waste heat boiler: The high-temperature process gas flows in the tube, the water is outside the tube, and the waste heat of the process gas is recovered to produce steam. Its structure is similar to that of a shell-and-tube heat exchanger.

The flue-type waste heat boiler is a water tube boiler. Water or steam flows in the tube of the heating tube, and the flue gas flows in the flue outside the heating tube. The flue gas transfers heat to the water or steam inside the tube by scouring the outer surface of the tube. Generally, flue-type waste heat boiler consists of superheating section, evaporation section, coal-saving section, steam drum, riser and downcomer.

The shell-and-tube waste heat boiler is a fire-tube boiler, the flue gas flows in the heated tube, and the water flows in the shell outside the tube. Heat is transferred through the tube wall to the water outside the tube. Usually, the shell and tube waste heat boiler only evaporates water, without superheating section and coal saving section. The large-scale shell-and-tube waste heat boiler has a steam drum, rising pipe, and descending pipe, while the small-sized shell-and-tube waste heat boiler uses the upper space of the shell for steam-water separation.