Research on improving comprehensive properties of a new sawdust composite insulation material by torrefaction

Abstract

Preparing insulation materials from biomass waste is an economic and effective method of resource utilization. In this work, an eco-friendly sawdust composite insulation material was produced with its fire resistance improved by torrefying the biomass and adopting fireproof geopolymers as inorganic binders. Raw sawdust, as the fire-proof weakness, was torrefied to increase the ignition point before being added to the biomass composite insulation materials. With the increase of torrefaction temperature or residence time, the ignition point of the torrefied sawdust increased from 270 °C to 360 °C when the solid yield decreased from 95 % to 34 % For the sawdust composite insulation materials, the best comprehensive performance was achieved with the solid yield of torrefied sawdust being 60 %, and the corresponding values of thermal conductivity, density, and compression strength were 0.087 W/(m.K), 430.8 kg/m3 and 0.97 MPa, respectively. Furthermore, the composite insulation materials can maintain structural integrity under high-temperature flame spraying and obtain a satisfactory carbon sequestration capacity. Due to the advantages of environmental protection, high fire resistance, and low thermal conductivity, the torrefied sawdust composite insulation material has good application prospects in buildings.