Less odor nuisances, less climate impact and higher fertilizer value are just some of the benefits of degassing slurry in a biogas plant before it is spread in the field.
A Danish farmer, who is running a large pig farm and a biogas plant, has invested DKK 14m in a pipe system to transport slurry from local farms to his biogas plant and then back to the fields, where the degassed slurry can be spread out.
On the manifolds between the farms and the biogas plant, AVK knife gate valves are installed to ensure that the slurry is sent off to the right places. Through automated control of opening and closing the valves, it is made sure that the slurry can be pumped in both directions within the system.
Pipe system reduces traffic load
Having the farms connected to the new pipe system saves both time and operating costs. Also, the system will reduce the traffic load and the challenges related to this. Slurry tankers will not have to drive back and forth between the farms and the plant, and by establishing buffer tanks and taps at the fields, the need for driving between the fields and storage tanks on the farms is minimised as well.
20 km of pipes
The ten farms, a pumping station and the biogas plant are connected through approx. 20 km of pipes. The biogas plant processes up to 160,000 tons of biomass every single year.
Less climate impact and odor nuisances
Slurry is pumped from each farm for degassing at the plant, from where it is pumped back to the farms for storage in tanks right next to the fields.
Degassing slurry before spreading it out has several advantages; the slurry then provides a higher fertilizer value, and at the same time it results in less odor nuisance and reduced methane emissions. Methane is a greenhouse gas that impacts the climate far more than CO2 does, and therefore degassed slurry means less impact on climate when it is spread in the field.
26 knife gate valves on the pipeline
The system is dimensioned with 200 mm PE pipes and for a maximum working pressure of 10 bar. Vatech 2000, part of the AVK Group, has delivered 26 AVK knife gate valves (DN200) with LINAK actuators (including motor/signal cables) for the slurry transportation project.
Electrical actuators have been chosen as the valves are installed over an extensive area and to allow for feedback modules, which can provide an easy overview of the actuators' settings.