Fluidized bed boilers equipped with fluidized bed combustion technology EFDM are suitable sources of heat for technological purposes and heating systems especially for economical operation, high efficiency (85 – 88%), good control ability, “en block” arrangement and also for wide range of usable fuels.

Fuels

Basic fuels of the fluidized bed boilers FK are additived brown coals hp1, hp2 and hp3. After recharge of additive bin with the fuel and additive dosing into boiler, it is possible to burn nonadditived brown coal too. Other usable fuels are black coal, wooden chips, biomass but also some wastes (solid, pasty, liquid). The boiler is equipped with appropriate device for flue gas cleaning according to type of combusted waste. The boiler is designed in order to enable (after a simple adjustment) combustion of several types of fuels alternately or at once. The boiler is able to combust natural gas too after adjustment.

Description

The “en block” arrangement of FK boilers with EFDM technology enables a simple and quick assembly, supplementary addition of other equipments (additive dosing, additive bin, supplementary fuel storage and transport, wet flue gas cleaning, dosing of pasty and liquid wastes). The technology also enables an increase of installed output or whole technology (including separate fuel transport and storage bins). The boilers are supplied in performance “steam”, “low-pressure steam”, “hotwater” and “warmwater” including accessories and fittings necessary for safety and reliable operation, with automatics controlling fluidized bed furnace operation and enables communication with superior control system. Design, manufacture, tests, accessories and fittings fulfill all ČSN requirements and other directives related to operation of such equipments.

Diagram of Fluidized bet boiler FK 2MW

Technology arrangement of fluidized bed boilers and scope of basic supply 
(see the picture above)
Fuel is brought into the storage tank of unmodified-fuel (9). From there the fuel is transported by a screw feeder (7) into the mill (11), from which the fuel falls into the storage tank of modified-fuel (10). From there the fuel is conducted by fuel conveyor (8) into the pneumatic feeder (7). By transport air the fuel is brought into the fluidized furnace (14). The fluidized furnace consists of the bottom with nozzles for inlet of fluidizated and combusted air. The furnace walls create water cooled boiler walls (13) welded from the diaphragm walls. Air for transport and combustion of the fuel is secured by high-pressure fan (17). For reaching the operation temperature of the fluidized bed is the boiler equipped with start-up device (12) - burner for liquid fuels (possible to supply also a burner for natural gas, propane butan, etc.), which its warm flue gas will fire the fuel in the fluidized bed. After fuel burn-off in the fluidized bed is the fly ash wafted by flue gas into the convection part of boiler, where its first separation occurs. The separated fly ash falls into the dump, from where the fly ash is by fly ash conveyor (19) brought onto the place of storage eg. into a container (20). Behind the convection part is placed the flue gas filter (21) or other type of flue gas cleaning (separation) from the solid particles (e.g. wet cleaning). The fly ash caught in the flue gas fabric filter is by the conveyor brought on the place of fly ash storage. Behind the filter, there is placed the flue gas fan (22), which carries the flue gas into the chimney.

The outputs and performance of fluid boilers FK

Technical parameters

Supplementary equipment

• Equipment for fly ash pelleting - ability to utilize the pellets from the fly ash in the building industry (sub-base material)
• Flue gas cleaning (washer)
• Water heater - for steam and hotwater boilers
• Steam superheater
• GESTRA equipment for operation of hotwater and steam boilers without constant supervision in intervals 1x in 24 hours
• Complete supply of boiler house technology including water treatment and control system as a whole or supply of particular components

Operation characteristics of boiler
The fluidized bed boilers with EFDM technology are characterized by these features

• Fast realization of heat source – due to “en block” layout
• Easy operation (operational comfort approaches to a high-quality boiler operation)
• Meeting emission limits (in case of prescribed fuel combustion)
• Minimum needs for maintenance
• Quick output adjustment
• Quick boiler start-up (boiler start-up while cold stand-by approx. 30 minutes, while warm stand-by approx. 5-10 minutes). The boiler enables a start without using start-up burner until 6 hours from shut-down.
• High operational reliability
• Wide control range
• The boiler enables combustion of two fuels alternately (supplementary fuel is admixed) or it is possible to alternate the fuels.
• The boiler enables additive dosing control according to specific composition of used nonadditived fuel
• In case of requirement it is possible to extend the supply with fuel feeding into unmodified fuel bin.

On the base of requirement, we are able to supply boilers with design pressure 2,5 MPa. Outlet water temperature from hotwater boiler must be at least 10°C lower than boiling temperature within operation pressure. It is possible to equip the boilers with water heater. It is possible to extend the supply of boiler accessories with GESTRA equipment for boilers operation without constant supervision in intervals 1x in 24 hours. It is possible to equip the boiler with steam superheater.

Guaranteed emission limits 
Emission limits according to provision FVŽP to the law no. 309/91.