An operations unit, comprising: a first chamber; a second chamber; a conduit extending through the first chamber and into the second chamber, the conduit being at least partially enclosed by a conduit jacket that defines an outer diameter, the conduit placing the second chamber into fluid communication with an environment exterior to the chamber, the second chamber comprising a wall facing the conduit jacket, and the second chamber being rotatable relative to the first chamber; a seal defining a boundary between the first chamber and the second chamber, the seal extending radially from the wall of the second chamber toward the conduit jacket, the seal comprising a flange, the flange defining an inner diameter, (a) the seal comprising a layered portion that comprises a plurality of ring-shaped portions, or (b) the seal comprising a brush that rotatably abuts the conduit jacket.