Steam boiler for solid fuels

DBW series biomass-fired boilers

The two-drum steam boilers have designed to generate saturated and superheated steam using various types of biomass, food and agricultural waste and have steam capacity from 4,0 to 10,0 t/h. The furnace is completely water-cooled using membrane wall construction. The boilers used reciprocating grate for fuel combustion.

The boiler operates both on wood chips and on complex fuels:

• husk of sunflower

• litter of poultry complexes

• Weeds of oats and other cereals

• Peat

• Lignin

• Corn stalk

• soybean waste

• Waste pellets

Boilers provide a fully automated operation mode without the need for a constant presence of maintenance personnel.

Equipment advantages:

• Burns various fuels from biomass. (humidity level up to 55 percent)

• Low NOX and CO emissions - optimum combustion. Correction of the combustion process occurs fully automatically

• Gas-tight execution of panels, automatic cleaning of surfaces

• Ability to burn low-quality fuel

• High boiler efficiency - at least 85% 

Fuel feeding system

  Fuel feeding system consists of screw feeders ( the number of the screw feeders depends on the steam boiler capacity), fuel bunker with level sensors. The screw feeders use to control biomass flow from the fuel bunker at a uniform rate.

Fuel is supplied to the boiler furnace through water-cooled wall which is mounted in the front of the reciprocating grate. This water-cooled wall prevents  ignition of fuel in the screw feeders at low loads. Temperature sensors are installed on the screw feeders bodies in case of fuel ignition and water supply for fire extinguishing is provided.

Reciprocating grate stoker

The reciprocating grate stoker consists of alternating rows of fixed and moving grate bars. The grate is devided into several air zones along the length which allows to achieve optimal results when burning different types of fuel. The undergrate air in combination with overfire air, which is fed though the nozzles located on the furnace wall, allows to achieve good results of emissions in the atmosphere. 

The moving speed and the shape of the grate bars depend on the fuel, the moisture content of which can be up to 55 %.

The grate bars are made of cast iron with a chromium content of 27%, which in combination with the optimized shape of the grate bars for different types of fuel, ensures a long life cycle of the grate.

Automation provides control, automatic control and protection of steam boiler from emergencies.  

Boiler control includes:

• Control the boiler drum water level;

• Control and regulation of pressure in the boiler;

• Rarefaction  regulation in the boiler furnace;

• Regulation of the amount of primary and secondary air;

• Furnace temperature control;

• Flue gases temperature control;

• Economizer inlet and outlet water temperature control;

• Fuel feed control;

• Reciprocating grate control;

• Automatic ash removal;

• Boiler protection

Consists of:

• boiler control panel

• fans control panel

• sensors and indicating devices

• actuators