Örebro Kartongbruk AB, Birka Värme AB in Sweden

Multi-fuel steam boiler plant based on industrial waste from cardboard industry

In November 1999 we were awarded the contract for the delivery of a steam boiler plant for Birka Värme AB. The plant is installed at the cardboard factory Örebro Kartongbruk AB, situated in Örebro, Sweden.

The fuel: waste from the cardboard factory and industrial waste

The fuel consists partly of wet and dry fractions of waste from the cardboard factory and partly of unsorted industrial waste including plastic, wood, and a fraction of incombustible material. The boiler generates saturated steam for use in the cardboard factory.

The Örebro multi-fuel energy plant is installed at the cardboard factory Örebro Kartongbruk situated in Örebro, Sweden. The steam is used in the cardboard factory’s drying process and for heating purposes.

Keeping fuel close to the grate with a dosing silo and water-cooled screw feeders

The fuel is delivered to a dosing silo from which it is distributed to four water-cooled screw feeders. In this way the fuel is kept close to the grate.

The industrial waste contains a certain amount of aluminium which will melt during combustion but will subsequently be cooled by the grate and carried out with the ash.

The different types of fuel receive preliminary treatment in order to divide the fuel into smaller particles and to mix the wet and dry material. The plant is equipped with a water-cooled vibrating grate.

Flue gas cleaning and NOx reduction

The boiler is provided with an SNCR plant for NOx-reduction.
The ash is delivered into containers for removal. The fly ash is gathered in so-called big bags for later disposal.

Bicarbonate is fed into the flue gas duct before the filter in order to reduce the amount of chlorides and sulphur dioxides in the flue gas. If necessary, active carbon can be added at a later stage for reduction of dioxins.

Recovering energy for the cardboard factory

The steam is used in the cardboard factory’s drying process and for heating purposes.

Plant design data

Process parameters Values
Nominal capacity 14 MW at 13.8 MJ/kg
Steam pressure and temperature 16 bar, 201 OC (saturated)
Steam production  22 t/h
Flue gas cleaning Baghouse filter with bicarbonate
Permitted emission values out of the boiler
Particles  20 Mg/Nm3 *)
NOx  49 mg/MJ
CO  90 mg/MJ
NH3 – slip  20 Mg/Nm3 after boiler
Measured during guarantee test
Particles  1-4 Mg/Nm3 *)
NOx  44 Mg/MJ
CO  1-17 Mg/MJ
NH3 -slip  < 20 Mg/Nm3 after boiler

*) Dry flue gas at 13% O2

The plant limit values comply with the waste incineration directive regarding co-combustion. The values are before flue gas cleaning. Naturally the plant in Örebro is equipped with a modern flue gas cleaning system.