Porosity and Thermal Properties of Carbon as Affected by Biomass Type and Production Method

Highlights Pore structure and thermal properties were evaluated for carbon obtained from the pyrolysis of six biomasses. Effect of biomass composition and pyrolysis parameters on the pore properties of the resulting carbon was investigated. Total pore volume and surface area were the lowest for carbon obtained from algal biomass. Carbon obtained from biomass pyrolysis is suitable for application in thermal insulation. ABSTRACT. This study investigated the pore structure, thermal conductivity, and thermal effusivity of carbon materials derived from six biomass types: eastern red cedar wood (CW), microalgal biomass (MB), digested sludge from municipal wastewater treatment facilities (DS), hazelnut (HN) and pecan shells (PS), and an equal weight mixture of CW-MB-DS (MIX). Pyrolysis process variables included temperature (500–700°C), hold time (1–4 h), and catalyst to biomass ratio (0–2). The study examined the complex effects of biomass chemical composition and production parameters on total pore volume, surface area, pore size distribution, and thermal properties of the resulting carbon. Among the samples, carbon derived from MB exhibited the lowest total pore volume (0.489 cm 3 /g) and surface area (1017.744 m 2 /g). It was predominantly microporous, with micropores accounting for approximately 83% of the total pore volume. The very low thermal conductivity (0.064 W/mK) and effusivity (197.9 Ws 1/2 /Km 2 ) observed in the samples suggest their strong potential for thermal insulation applications. This is the first study evaluating correlations between pore size distribution and thermal properties across multiple biomass types. The findings of this study provide valuable insights for selecting suitable biomass sources and optimizing production methods to design carbon materials with tailored pore structures and thermal characteristics for specific applications. Keywords: Biochar, Biomass, Pore size distribution, Porous carbon, Pyrolysis, Thermal conductivity, Thermal effusivity.