Bulky paper and board at a high dry solids content with foam forming

In foam forming fibres are dispersed into an aqueous foam, which prevents fibre flocculation and improves product quality. The potential of foam forming technology has been demonstrated several times in laboratory scale experiments but there are only a few studies performed in realistic process conditions. In this paper we introduce results from recent trials done at VTT's SUORA pilot environment. We show how foam forming leads to several percentage points higher dry solids content after the press section, which implies even 20% savings in drying energy. At the same time, foaming improves bulk and formation. We further demonstrate that in the case of forming with foam, cellulose nanofibrils (CNF) can be used as a strength additive without negative impact on dewatering or formation