An integrated approach to the valorization of pyrolysis products from lignocellulosic residues and by-products
María del Carmen Recio-Ruiz, Ramiro Ruíz-Rosas, Francisco José García‐Mateos, María José Valero-Romero, Juana M. Rosas, José Rodríguez‐Mirasol, Tomás Cordero
Abstract
Pyrolysis of biomass waste enables the generation of energy and products, although the sustainability of this process requires an integral valorization of all produced fractions. This paper presents a study on the valorization of all pyrolysis products from selected biomass wastes, such as hemp hurd (HH), olive stone (OS) and almond shell (AS), and two technical lignins, focusing on the effect of the biopolymeric composition on the potential applications of the different pyrolysis streams. The stablished correlation between the lignocellulosic biomass composition and the properties of each of the pyrolysis products obtained (bio-oil, biochar and gases) in relation to their potential applications (in addition to the distribution of pyrolysis products and yields) represents the main novelties of this work. The results obtained demonstrate that it is possible to obtain energy to sustain an autothermal pyrolysis process from these residues at operation temperatures above 500 °C. Residual biomass materials with high lignin content deliver gases with higher heating values (up to 23 MJ/m 3 ), higher yields of solids (ca. 58 %), and bio-oil with lower acid and higher phenolic content (up to 19.9%m/m.). Agricultural residues, especially hemp hurd, which contains lower lignin amount, produce chars with narrow microporosity, matching the requirements to selectively adsorb CO 2 from biogas and steam reforming streams, achieving CO 2 /CH 4 selectivity values as high as 53. • Full characterization of the slow pyrolysis products of five biomass residues. • Olive stone and Hemp hurd, potential feedstocks for bio-oil production. • Lignin produces biochar with low H/C ratio and non-condensable gases with high LHV. • The biochars obtained present very narrow microporosity suitable for CO 2 capture. • Biochar from hemp hurd selectively adsorbs CO 2 from pyrolysis gas.