Storde Biogas I/S’s biogas plant was built in 2018 and is owned by Brian Bech, Jan Dahlmann, and Niels Dahlmann. The biogas plant produces 5,200,000 m³ of gas annually. The owners supply most of the slurry and deep litter to the plant, with the remainder coming from other suppliers. In 2022, Linka Energy A/S delivered a 2.0 MW hot water boiler system based on wood chip firing to Storde Biogas I/S.

The boiler system consists of a 2.0 MW Linka® H 2000 hot water boiler, which handles wood chips. A 40-foot container, in which a walking floor (scraper system) is built, conveys the fuel to a sunken cross auger at the end of the scraper system.

The wood chips are then transferred via a series of inclined augers directly to the cell lock, which is positioned above the stoker auger on the boiler. Through the cell lock, the wood chips fall into the stoker auger, which then transports them to the moving step grate located at the front of the boiler. The fuel quantity is controlled by an oxygen sensor that measures the oxygen content in the flue gas. In the boiler’s combustion chamber, a moving step grate is installed to minimize slag formation, and Linka’s own globally patented co-current combustion system ensures that heated combustion air is supplied to recirculate the flue gases, thereby maximizing the utilization of the wood chip. The shot valves on the boiler blow air through the boiler’s flue tubes, cleaning them of ash, which means the boiler’s flue tubes rarely need to be cleaned manually.

An economizer ensures the recirculation of flue gases, thereby maximizing the utilization of the wood chips.

Briefly described, an economizer acts as a sort of flue gas cooler, where energy is transferred from the hot flue gas to a cooler medium – in this case, water – which can then be used for preheating or heating. In this way, the efficiency of the plant is increased, as more energy is extracted from the same amount of fuel. The economizer is connected to the flue gas system right after the boiler and before the multicyclone. Additionally, multicyclones and a bag filter are installed to clean the flue gas, thereby reducing dust emissions through the 17-meter-high steel chimney. The ash is finally transported to a new 12 m³ ash container.

The complete plant is controlled via a PLC control system, which monitors the plant and ensures controlled regulation of fuel supply and operation, thereby always achieving maximum efficiency from the plant. The PLC system sends out alarms in case of deviations from the preset set points via the internet and SMS. It is also possible to monitor the plant via smartphones, tablets, and/or PCs.