Char Valorization into Sustainable and Performant Polyurethane Insulating Panels

Abstract

River maintenance is required for environmental risk management; however, the resulting vegetable biomass owns poor properties that preclude its treatment in an energy power plant. Nevertheless, the large availability of river biomass and a possible valorization of the by product from the gasification process (namely char, a fine-grained vegetable carbon) can encourage and make this operation more sustainable. If the use of char as soil or substrate improver has been widely studied in the last 15 years, the application of this substance for construction materials or composites is starting to gain more attention recently. Indeed, in addition to the great advantage of carbon sequestration, the use of char can reduce the energy associated with the production process of such materials by decreasing the consumption of raw materials. In this work, char deriving from the gasification process of local river biomasses is fully characterized and used in different ratios in polyurethane panels for insulating purpose. Remarkably, polyurethane panels show an enhancement in thermal insulating power and electric conductivity by increasing the char content. Enhancements in terms of mechanical properties are also observed for maximum char content up to 1 wt%. In contrast, higher content results in preventing a good development of polymerization and consequently of good properties. Precisely, the char use significantly increases the maximum load in stress-relaxation tests and improves the load recovery after 10 min, whereas higher elastic modulus and compressive strength values are observed in compressive tests. The char effectiveness toward more sustainable and performant insulating materials is demonstrated.

Innovative Pathways for the Valorization of Biomass Gasification Char: A Systematic Review

“…Gasification of biomass from riparian vegetation maintenance in a region in Italy was mixed with polyurethane at a ratio of 0-2 wt.%. The results showed reduced thermal conductivity from 0.044 to 0.037 W mK −1 for the cases of no char and 0.5 wt.% char [120]. Moreover, char from a pilot-scale fluidized bed gasifier utilizing olive mill cake as a feedstock was tested as an additive in brick manufacturing [121].…”