Boiler output: 3.500 kWth (0,5 MWel)
Combustion system: hydraulic reciprocating step grate
Fuel: waste wood, wood chips
Year of construction: 2018
On November 26, 2019, the MIGROS Cooperative Lucerne put into operation a biomass heating plant in their headquarters ins Dierikon. Besides heating for the company premises as well as the adjoining properties, it offers cooling and electricity for the company’s own consumption.
Waste wood of the classes I, II and III is supplied to the firing in the form of 100 mm shredded wood chips from an underground storage bunker by means of a hydraulic discharge and conveyor system. The combustion plant features an adiabatic combustion chamber and a hydraulic push grate. After the complete combustion of the wood fuel, the hot flue gases flow through the high-pressure water-tube steam boiler with a nominal output of 3.5 MW. Downstream, the flue gases are led into the superheater to increase the steam temperatures and afterwards into the economiser to reduce the flue gas temperature. The superheated high-pressure steam with 35 bar/420∞C is supplied to an extraction condensing steam turbine with a coupled generator for the energy generation of 500 kW/h. After the turbine, the steam is led with reduced pressure to the steam warm-water converter (condenser) and the condensate is led through the economiser within the system back to the steam boiler to be heated up. The warm water from the steam warm-water converter is used for the heating of the MIGROS buildings as well as the warm water supply and the local heating network for the Dierikon/Lucerne region. Thanks to the high temperature levels that are possible around the whole year, this heat can also be used to produce cooling. The power plant is controlled by a PLC developed by Polytechnik. All operational data is visualised and saved chronologically. Polytechnik plants can be monitored, controlled and serviced via remote maintenance (Remote Control). The trained MIGROS staff and the Polytechnik staff can access the visualisation via internet at any time and from any place to adjust the operational parameters, if necessary.