Industrial Systems / Firing Systems / UTSW

Moving step grate firing system UTSW

Operating medium:	water / hot water / steam
Grate cooling:	water
Operating range:	300 - 4200 kW
Capacity regulation:	modulating
Water content:	M 8 - 44
Fuel types:	scrap wood / residual wood / pellets / alternative fuels

Fuels with an extremely high calorific value or low ash melting point, such as particleboard waste, old timber, corn, rice husks.

Applications

Furnaces for special fuels such as grains/corn, etc.
Crushed wood
Pellets and industrial pellets
Particleboard furnaces in the wood processing industry

Fuel supply with stoker screw
Combustion chamber with water cooling
Water-cooled step grate
Burnout zone
Under-grate de-ashing – automatic or manual
Automatic grate ash discharge
Access door to under-grate
Radiation vault
Refractory concrete with defined heat passage
Secondary combustion chamber – in accordance with low NOx process
by means of air stages
3-pass steam boiler
Boiler door with automatic pulse-jet cleaning system of the boiler tubes
Flue gas cleaning by multi-cyclone with automatic fly ash discharge
Flue gas fan – can be positioned either on the right, left or at the rear
Grate door with safety lock

The UTSW boiler unit is equipped with a step moving grate and also suitable for fuel with a high ash content. The fuel is fed on to the sloping feed grate from the rear of the furnace. The grate consists of water-cooled grate girders; the rods overlap on both sides, so that the minimum fuel slips through the grate. Furthermore, the grate is designed to enable a clear, uniform distribution of the primary air supplied to the various zones, thereby creating a steady, undisturbed gasification zone. The grate carriage has a hydraulic drive, so that the movement intervals can be automatically adjusted to the capacity. The entire combustion chamber is water-cooled and lined with fireproof material, thereby ensuring the required cooling even in the case of fuel that generate a high temperature in the combustion chamber.

Combustion chamber design

Insulation of the combustion chamber (100 mm) with external cladding plate
Water cooling inside double-walled steel plate structure connected with tension bolts
Fireproof ceramic fibre mat coated with aluminium foil
Heat resistant wall anchors
Fireproof cast concrete (100 mm)

The refractory concrete is secured to the steel structure of the combustion chamber with heat resistant wall anchors. The refractory concrete has a high density as well as a high temperature resistance and is cast in sections. Dilation seams between the sections compensate for expansion of the refractory concrete when the temperature fluctuates. The ceramic fibre mat behind the refractory concrete protects the steel plate structure against overheating.