New mixing system defeats biogas digester crust at leading pig producer
The Roslev-based business (established 1933), which includes pig production, plant breeding and green energy, first encountered problems with its existing propeller stirrers when a steel wire broke, as Ny Rybjerggaard’s owner, Jens Henry Christensen explains: “In one of our reactor tanks (3,300 m³), it transpired that a stirrer that was meant to be operating at the top of the digester had only been running at the bottom, because the wire to raise the propeller stirrer was broken.”
He added: “In no time at all, a floating layer had formed at the top – and although we had the stirrer repaired, the problem remained. It seriously hampered agitation and circulation of the straw and slurry feedstock that we use for our biogas operation. This situation highlighted the limitations to us of propeller-type equipment for this application, which can’t really cope with dry matter – so we knew it was time to find a superior, long-lasting, low-maintenance mixing system.”
To alleviate...