Circulating Fluidized Bed Boiler
Circulating Fluidized Bed combustion has given boiler and power plant operators a greater flexibility in burning a wide range of coal and other fuels. But the question is how does CFB boiler work. In the olden days blacksmiths used to heat the iron by placing it on a bed of coal. Bellows provide air to the coal from the bottom of the bed. Fluidized Bed combustion is something similar to this.
Circulating Fluidized Bed Boiler Workflow
At the bottom of the boiler furnace there is a bed of inert material. Bed is where the coal or fuel spreads. Air supply is from under the bed at high pressure. This lifts the bed material and the coal particles and keeps it in suspension. The coal combustion takes place in this suspended condition. This is the Fluidized bed. Special design of the air nozzles at the bottom of the bed allows air flow without clogging. Primary air fans provide the preheated fluidizing air. Secondary air fans provide pre-heated Combustion air. Nozzles in the furnace walls at various levels distribute the Combustion air in the furnace.
Fine particles of partly burned coal, ash and bed material are carried along with the flue gases to the upper areas of the furnace and then into a cyclone. In the cyclone the heavier particles separate from the gas and falls to the hopper of the cyclone. This returns to the furnace for re-circulation. Hence the name is Circulating Fluidized Bed combustion. The hot gases from the cyclone pass to the heat transfer surfaces and go out of the boiler.
Different boiler manufacturers adopt different methods of cyclone separation , but the basic principles remain the same.
ZG Boiler supply two types QXX hot water CFB boiler, QXX high-speed external circulating fluidized bed boiler and QXX low-speed internally circulating fluidized bed boiler. Both of them have high efficiency and low cost in combustion. With 70 year’s experience on innovation, ZG boiler is the product you can rely on.