Modern hard coal fired boiler plants

  Modern boiler plants fired by hard coal


Rights from the beginning of its operation Energotechnika has been handling production and 

construction of boiler plants fired by solid fuels, and in particular hard coal and biomass. In 

response to needs of the market, in connection with implementation of the Directive of the 

European Parliament EU 2015/2193 of 25 November 2015 on the limitation of emissions of 

certain pollutants into the air from medium combustion plants, Energotechnika has developed 

a new family of coal fired boilers that meet the most stringent environment protection 


Line HEWB series E1015 boilers with economisers are modern water stoker boilers fired by 

hard coal dust with a three-pass fuel gas flow with reduction of emission of noxious 

substances. This type of boilers, with a maximum capacity of 30MW, are designated for 

production of hot water with parameters of 150/70°C. 

The first boiler pass is the furnace chamber, in the second vertical one convectional bund has 

been installed, while the third pass is constituted by a detached full-flow water heater 

(economizer) in steel sheet casing. The boilers are executed on the basis of sheet piling 

technology, which allows boiler operation on negative air pressure, without the additional 

losses caused by air suction to the inside. The device is self-bearing, footed on eight support 



Flue gas dust collection, denitrification and desulphurisation system 


The boiler is originally furnished with a complete flue gas dust collection, denitrification and 

desulphurisation system. The dust collection system comprises a preliminary dust collector, 

multicyclone and a bag filter with a bag purification system, and with an exhaust fan and with

flue gas channels between the boiler and the chimney. 

Reducing the contents of nitrogen compounds takes place on the basis of the flue gas 

recirculation system. Introduction to the furnace chamber of a part of flue gas streams flowing

out  from the boiler causes lowering of the combustion temperature and as an effect reduction 

of nitrogen compound contents. In addition, in the upper part of the second pass connecting 

pipes are provided for injecting ammonia water (SNCR), as an additional option for reducing 

nitrogen contents. Fuel gas desulphurisation takes place in the dry method by injecting 

sodium carbonate or bicarbonate to the flue gas duct prior to the bag filter. 


Control system 


Boilers from the HEWB family have been equipped with the most modern automation 

system, in accordance with binding regulations. The control and instrumentation cabinet is 

furnished with circuits to control all boiler systems, and in particular:​

  • Fuel feeding system 
  • Primary air regulation system 
  • Secondary air regulation system
  • Flue recirculation system
  • Negative air pressure regulation system in the furnace chamber 
  • Control system for boiler operating parameters 
  • Boiler capacity regulation system 
  • System of alarms with boiler protection circuits 
  • Desulphurisation system
  • Dust collection system
  • System of active NOxreduction

Thanks to the automation of the control proves of a boiler, units type HEWB are characterised

by an extremely high efficiency and regulation capacity within the range of 30 to 100% of 

nominal load.

Basic parameters 
 Range of offered boiler capacity  3,5-30MW
 Regulation capacity  30-100%
 Efficiency at nominal capacity   >88%
 Efficiency at a load of 30%   >86%
 Dust emission (at 6% O2)  <30mg/Nm3
 SOx emission (at 6% O2)  <400mg/Nm3
 NOx emission (at 6% O2)  <300mg/Nm3

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