Comparison of fibers from hop rich biogas digestate with natural fibers as raw material for composites

Abstract

Fibrous material extracted from biogas digestate is investigated as a possible raw material for composites. Digestate is a by-product of every biogas plant and consists mostly of water, undegraded plant biomass, and minerals. On the other hand, natural fibers and fibrous by-products are increasingly used as fiber component, especially in short-fiber reinforced plastics. The fibrous solid fraction of biogas digestate can be another alternative fiber source. The properties are decisive to determine the suitability of raw materials. Information on the length and constituents of woody and various non-woody plants can be found in the literature. In the study presented, fibrous solids obtained from digestate with a high content of hop vines are investigated. Fiber length and cell wall matter content are analyzed to characterize the digestate. The results are compared with classical plant fibers. It turns out that the investigated fibrous solids from digestate have a very inhomogeneous length distribution. The equalization can be achieved through an additional process step. The proportion of cell wall matter is comparable to that of woody plants and various non-woody plants. The fibers extracted from hop digestate can be regarded as an ecological and favorable alternative to wood fibers in composite materials.

Keywords

• word
• biocomposites
• biogas digestate
• natural fibers
• waste