Gram Fjernvarme A.m.b.a.

As part of a comprehensive upgrade of its heating system, Gram Fjernvarme decided to install a new wood pellet boiler after decommissioning its old gas engine, which had been in operation since 1995 with nearly 60,000 operating hours. The space previously occupied by the gas engine and an old gas boiler was repurposed for the installation of a 2.0 MW wood pellet boiler from Linka Energy, along with a 3.0 MW heat pump system from another supplier. With these new systems, combined with the existing solar thermal plant, Gram Fjernvarme is now independent of electricity and natural gas price fluctuations.

The new installations were expected to enhance heat supply efficiency and were part of a strategy to reduce CO2 emissions and optimize operational costs compared to previous heating methods.

The new wood pellet boiler at Gram Fjernvarme was designed to function as a peak load and backup supply unit with a capacity of 2 MW. It was integrated into the existing system to utilize residual heat from the solar thermal plant. Additionally, the existing chimney was reused, incorporating a new internal liner. To ensure operational safety and compliance with regulations, the system includes two independent backfire prevention mechanisms in the fuel feeding system.

The new Linka® 2.0 MW wood pellet boiler is engineered to optimize efficiency and reduce CO2 emissions. It was selected primarily for wood pellet combustion but is also capable of burning alternative biomass fuels such as straw pellets, wood chips, and sunflower seed husks. This flexibility allows the system to be adapted for other biomass types if needed.

The boiler is equipped with a specially designed stoker featuring two parallel stoker augers, ensuring optimal fuel distribution across the entire grate width and efficient handling of the fuel (wood pellets).

To maximize energy efficiency, the system includes a Linka® H-boiler with a cylindrical combustion chamber, ensuring optimal combustion. Linka’s patented combustion technology and the moving step-grate system inside the chamber minimize slag formation and enhance combustion efficiency.

Flue gas treatment is an integral part of the system, significantly reducing environmental impact. The flue gas passes through multiple filtration stages: first through a multi-cyclone and then a bag filter, effectively minimizing particulate emissions before being released through the existing chimney. This advanced cleaning process ensures compliance with strict emission standards and contributes to a cleaner environment.