Veesons Energy Systems Pvt. Ltd. Offers Drum Type Atmospheric Fluidsed Bed Combustion - AFBC Boiler. Veesons Energy Systems Pvt. Ltd. Has achieved ISO 9001:2008 certifications. Drum Type Atmospheric Fluidsed Bed Combustion - AFBC Boiler is used when sand in a fluidized state is heated to the ignition temperature of the fuel and the fuel is injected continuously into the bed, the fuel will burn rapidly and the bed attains a uniform temperature due to effective mixing. Drum Type Atmospheric Fluidsed Bed Combustion - AFBC Boiler is essential that temperature of bed should be at least equal to ignition temperature of fuel and it should never be allowed to approach ash fusion temperature to avoid melting of ash. This boiler is achieved by extracting heat from the bed by conductive and convective heat transfer through tubes immersed in the bed.