Hydrothermal torrefaction of mixtures of biomass and hydrocarbon-rich sludge in the presence of fossil fuels

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Abstract

A new process for the torrefaction of mixtures of biomass and oily sludges is proposed. A fossil fuel (gasoline or diesel) was added to mixtures of biomass and hydrocarbon-rich sludge (10:1), and this mixture was subject to distillation until all liquids are recovered. The fossil fuel partially dissolved the sludge components and promoted their evenly distribution over the biomass particles. During distillation, the fossil fuel and all the distillable components present in the biomass and sludge were collected and the mixture was subject to temperatures at which a considerable transformation of the non-distillable fraction occurred. The biomass lost water and suffered partial decomposition and rearrangement to yield biochars with HHV of 23.6 and 33.2 MJ/kg. The original biomass had a HHV of 17.9 MJ/kg, but the hydrothermal torrefaction process as well as the fortification with heavy hydrocarbons from the oily sludge significantly increased its calorific value. The distillable liquids were recovered in the form of two immiscible liquid phases: (a) an organic phase mainly composed by the added fossil fuel but also containing the nonpolar volatile components present in the sludge and the biomass, and (b) an aqueous phase that contained the free and emulsified water present in the biomass and in the sludge, but also the water and polar organic components released from the mixture during this thermal treatment. This process takes place at atmospheric pressure and temperatures lower than 300 °C and can be applied to different sludges with high carbon content to promote their energetic valorization.

Original languageEnglish
Title of host publicationInnovation, Engineering and Entrepreneurship
EditorsGermano Veiga, Jose Machado, Filomena Soares
Place of PublicationCham
PublisherSpringer
Pages705-711
Number of pages7
ISBN (Electronic)978-3-319-91334-6
ISBN (Print)978-3-319-91333-9
DOIs
Publication statusPublished - 2019
Event3rd Conference on Innovation, Engineering and Entrepreneurship, Regional HELIX 2018 - Guimaraes, Portugal
Duration: 27 Jun 201829 Jun 2018

Publication series

NameLecture Notes in Electrical Engineering
PublisherSpringer
Volume505
ISSN (Print)1876-1100
ISSN (Electronic)1876-1119

Conference

Conference3rd Conference on Innovation, Engineering and Entrepreneurship, Regional HELIX 2018
CountryPortugal
CityGuimaraes
Period27/06/1829/06/18

Keywords

  • Biomass
  • Hydrothermal torrefaction
  • Oily sludges

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