González-Arias J, Carnicero A, Sánchez ME, Martínez EJ, López R, Cara-Jiménez J. Management of off-specification compost by using co-hydrothermal carbonization with olive tree pruning. Assessing energy potential of hydrochar.
Waste Manag 2021;
124:224-234. [PMID:
33631447 DOI:
10.1016/j.wasman.2021.01.026]
[Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Revised: 12/31/2020] [Accepted: 01/19/2021] [Indexed: 06/12/2023]
Abstract
In this work the management of a waste called off-specification compost (OSC) was proposed via hydrothermal carbonization (HTC). The composition of this residue makes it not suitable for agronomic purposes because of the Spanish regulation requirements. Therefore, a way of management and/or valorisation needs to be found. The energy recovery through co-HTC with olive tree pruning (OTP) was evaluated. Blending of OSC with lignocellulosic biomass allows to obtain a coal-like product with physicochemical properties similar to those of a lignite, characterised by its high carbon content. Blends of 25, 50 and 75% of OSC with OTP were analysed. The individual OSC does not present good parameters for being used as solid fuel based on its chemical composition, however, the blend of 75% of biomass with 25% of OSC does. With a higher heating value of 26.19 MJ/kg, this blend shows the best energy yield and energy densification ratio. Thermogravimetric and kinetic analysis reveal that as biomass content in the blend increases, the more the hydrochar behaves as a solid fuel, therefore OSC can be used for energy purposes while its current use of landfill disposal can be reduced.
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