In all Fluidized Bed Boilers, there is a bed of hot sand, ash & fuel.
The Screened fuel of size less than 6mm is delivered into the combustion chamber.
Fresh air which facilitates fluidization of bed and combustion is compressed to a pressure adequate to overcome the system resistance and forced through the fluidized bed after being preheated in the air heater.
The combustion takes place in the combustor. Heat is transferred from the products of combustion (flue gas) to water, steam and air as they pass through the various heat transfer surfaces before exiting through the stack.
Low combustion temperature and low excess air minimize the NOx generation.
The operational characteristics of BFBC ensure total fuel flexibility.
Design features of BFBC Boiler
-   Furnace made of gas tight membrane walls which are fabricated by automatic panel processing machine installed at our factory
-   Bed coil of seamless steel tubes of American Standard
-   Both Bi-drum/Single drum configurations are offered
-   Baffleless bank tube eliminates refractory baffle in the bank and related maintenance problem.
As there is no turning in the gas path, bank tube erosion is also avoided in Bi-drum boiler
-   There is a jacket in the fuel nozzle through which combustion air also passes and helps the combustion of fuel
which falls around the fuel nozzles. This avoids formation of clinker around the fuel nozzles
-   The wetted parts of mixing nozzles are made of Nihard Cast iron, which protects the mixing nozzles from erosion
-   Cassette Baffle is provided for economizer bends, so that gas will not pass through bends
which in turn protect economizer bends from erosion
-   Surge hopper is provided above fuel feeders to avoid load due to the bunker with fuel
coming on to the feeders which in turn facilitate free fuel flow through the feeders
-   There are no bends in fuel transport piping, thus avoiding erosion
-   Vertical travel of fuel from cross to fuel nozzle is minimal
Advantages of BFBC Boiler
-   Ability to burn low grade fuels and multi fuel capability
-   Higher thermal efficiency compared to conventional type boilers. Lesser auxiliary power consumption
-   Operational Flexibility
-   Low excess air.
-   Compact boiler size. Start-up operation is less complex
-   Low SO2 emission and ability to burn high sulphur Coal
-   Low NOx emission
BFBC Technology offers Fuel Flexibility
-   Indian coal
-   Imported coal
-   Meghalaya coal
-   Washery Rejects
-   Kutch lignite
-   Neyveli lignite
-   Raw lignite
-   Barmer lignite
-   Nagor lignite
-   Bhavnagar lignite
-   Natural Gas.
-   Rice husk
-   De-oiled Rice Bran [DOB]
-   Ground Nut Shell
-   Saw dust
-   Coffee husk
-   Bagasse pith
-   Coconut shell
-   Julia flora
-   Cotton stalk
-   Bamboo dust
-   Castor De-oiled cake