Upgrading biomass by hydrothermal and chemical conditioning
type: CreativeWork
description: There are two widely known thermal pretreatment technologies, known as hydrothermal carbonization and dry torrefaction. In dry torrefaction, also known as torrefaction or mild pyrolysis, dry solid biomass is treated in an inert gas environment in a temperature range of 200-300oC for more than one hour. In hydrothermal carbonization (HTC), also known as wet torrefaction, biomass is treated with hot compressed subcritical water (200-260oC) for 5 min-8 h. The solid product, HTC biochar, contains about 55-90% of the mass and 80-95% of the fuel value of the original feedstock. The HTC process takes any wet waste biomass and converts it to a homogenized, friable, hydrophobic, and, mass and energy densified HTC biochar similar to lignite coal. Subcritical water, the temperature between 180-280 °C has ionic strength much higher than water under ambient condition. Hemicellulose hydrolysis occurs at temperatures as low as 180 °C, while cellulose hydrolysis starts around 220-230 °C. Many monomers, aldehydes, and intermediates are produced as a result of hydrolysis of biomass. Reactive intermediate species promote chemical reactions such as decarboxylation, dehydration, aromatization, and condensation-polymerization in the presence of subcritical water. As a result of these reactions, complete degradation of hemicellulose and partial degradation of cellulose was observed in the solid phase. Some carbon-rich cross-linked hydrophobic polymers are produced from the cellulose hydrolyzed intermediates. Van Soest fiber analysis is incapable of distinguishing those new cellulose-derived polymers from naturally present lignin. Slagging and fouling are two major problems that result from biomass combustion or co-firing with coal, especially for the biomass with high inorganic content. HTC provides biochar with the slagging and fouling indices which will predict slagging and fouling, regardless of the biomass type, primarily due to reduced chlorine content. Hot compressed water leaches b…
abstract: There are two widely known thermal pretreatment technologies, known as hydrothermal carbonization and dry torrefaction. In dry torrefaction, also known as torrefaction or mild pyrolysis, dry solid biomass is treated in an inert gas environment in a temperature range of 200-300oC for more than one hour. In hydrothermal carbonization (HTC), also known as wet torrefaction, biomass is treated with hot compressed subcritical water (200-260oC) for 5 min-8 h. The solid product, HTC biochar, contains about 55-90% of the mass and 80-95% of the fuel value of the original feedstock. The HTC process takes any wet waste biomass and converts it to a homogenized, friable, hydrophobic, and, mass and energy densified HTC biochar similar to lignite coal. Subcritical water, the temperature between 180-280 °C has ionic strength much higher than water under ambient condition. Hemicellulose hydrolysis occurs at temperatures as low as 180 °C, while cellulose hydrolysis starts around 220-230 °C. Many monomers, aldehydes, and intermediates are produced as a result of hydrolysis of biomass. Reactive intermediate species promote chemical reactions such as decarboxylation, dehydration, aromatization, and condensation-polymerization in the presence of subcritical water. As a result of these reactions, complete degradation of hemicellulose and partial degradation of cellulose was observed in the solid phase. Some carbon-rich cross-linked hydrophobic polymers are produced from the cellulose hydrolyzed intermediates. Van Soest fiber analysis is incapable of distinguishing those new cellulose-derived polymers from naturally present lignin. Slagging and fouling are two major problems that result from biomass combustion or co-firing with coal, especially for the biomass with high inorganic content. HTC provides biochar with the slagging and fouling indices which will predict slagging and fouling, regardless of the biomass type, primarily due to reduced chlorine content. Hot compressed water leaches b…
author: Reza, Mohammad T.
keywords: Biomass pretreatment, Demineralization by chelation, Hydrothermal carbonization, Pelletization, Sludge, Torrefaction
date published: 2013
date modified: 2026-07-27T21:47:47Z
provider: University of Nevada - Reno
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Nevada - Reno

PropertyValue
property ID: Handle
value: http://hdl.handle.net/11714/3029