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Nielsen R.P.,University of Aalborg | Olofsson G.,SCF Technologies A S | Olofsson G.,Ramboll | Sogaard E.G.,University of Aalborg
Biomass and Bioenergy | Year: 2012

The CatLiq process is a thermochemical conversion of wet biomass with process conditions near the critical point of water. Although the technology shares similarities with other thermochemical conversion processes such as liquefaction, pyrolysis and gasification it cannot be fully classified as one of these technologies. The process is a continuous process using both heterogeneous and homogeneous catalysts as well as the properties of near-critical water to achieve a conversion of biomass into a bio-oil product and a product gas. The CatLiq process is compared to these other thermochemical conversion methods to give a view of the similarities as well as the differences, including process conditions, feedstock requirements and product types. © 2012 Elsevier Ltd. Source


Toor S.S.,University of Aalborg | Rosendahl L.,University of Aalborg | Nielsen M.P.,University of Aalborg | Glasius M.,University of Aarhus | And 2 more authors.
Biomass and Bioenergy | Year: 2012

Bio-refinery concepts are currently receiving much attention due to the drive toward flexible, highly efficient systems for utilization of biomass for food, feed, fuel and bio-chemicals. One way of achieving this is through appropriate process integration, in this particular case combining enzymatic bio-ethanol production with catalytic liquefaction of the wet distillers grains with soluble, a byproduct from the bio-ethanol process. The catalytic liquefaction process is carried out at sub-critical conditions (280-370 °C and 25 MPa) in the presence of a homogeneous alkaline and a heterogeneous Zirconia catalyst, a process known as the Catliq ® process. In the current work, catalytic conversion of WDGS was performed in a continuous pilot plant with a maximum capacity of 30 dm 3 h -1 of wet biomass. In the process, WDGS was converted to bio-oil, gases and water-soluble organic compounds. The oil obtained was characterized using several analysis methods, among them elementary analysis and GC-MS. The study shows that WDGS can be converted to bio oil with high yields. The results also indicate that through the combination of bio-ethanol production and catalytic liquefaction, it is possible to significantly increase the liquid product yield and scope, opening up for a wider end use applicability. © 2011 Elsevier Ltd. Source


Toor S.S.,University of Aalborg | Rosendahl L.,University of Aalborg | Rudolf A.,SCF Technologies A S
Energy | Year: 2011

This article reviews the hydrothermal liquefaction of biomass with the aim of describing the current status of the technology. Hydrothermal liquefaction is a medium-temperature, high-pressure thermochemical process, which produces a liquid product, often called bio-oil or bi-crude. During the hydrothermal liquefaction process, the macromolecules of the biomass are first hydrolyzed and/or degraded into smaller molecules. Many of the produced molecules are unstable and reactive and can recombine into larger ones. During this process, a substantial part of the oxygen in the biomass is removed by dehydration or decarboxylation. The chemical properties of bio-oil are highly dependent of the biomass substrate composition. Biomass constitutes of various components such as protein; carbohydrates, lignin and fat, and each of them produce distinct spectra of compounds during hydrothermal liquefaction. In spite of the potential for hydrothermal production of renewable fuels, only a few hydrothermal technologies have so far gone beyond lab- or bench-scale. © 2011 Elsevier Ltd. Source


Tyrsted C.,University of Aarhus | Becker J.,University of Aarhus | Hald P.,University of Aarhus | Bremholm M.,University of Aarhus | And 5 more authors.
Chemistry of Materials | Year: 2010

In situ synchrotron powder X-ray diffraction (PXRD) measurements have been conducted to follow the nucleation and growth of crystalline Ce xZr1-xO2 nanoparticles synthesized, in supercritical water with a full substitution variation (x = 0. 0.2, 0.5, 0.8, and 1.0). Direction-dependent growth curves are determined and described using reaction kinetic models. A distinct change in growth kinetics is observed with increasing cerium, content. For x = 0.8 and 1.0 (high cerium content), the growth, is initially limited by the surface reaction kinetics; however, at a size of ∼6 nm, the growth changes and becomes limited by the diffusion of monomers toward the surface. For x = 0 and 0.2, the opposite behavior is observed, with the growth initially being limited by diffusion (up to ∼3.5 nm) and later by the surface reaction kinetics. Thus, although a continuous solid solution can be obtained for the ceria - zirconia system, the growth of ceria and zirconia nanoparticles is fundamentally different under supercritical water conditions. For comparison, ex situ synthesis has also been performed using an in-house supercritical flow reactor. The resulting samples were analyzed using PXRD, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM). The nanoparticles with x = 0, 0.2, and 0.5 have very low polydispersities. The sizes range from 4 nm to 7 nm, and the particles exhibit a reversibly pH-dependent agglomeration. © 2010 American Chemical Society. Source


Becker J.,University of Aarhus | Toft L.L.,University of Aarhus | Aarup D.F.,University of Aarhus | Villadsen S.R.,University of Aarhus | And 3 more authors.
Energy and Fuels | Year: 2010

In this paper, we report on the construction of a novel test facility for evaluating catalytic processes at high temperature and high pressure. The design features make the facility well-suited for highly controlled studies of hydrothermal conversion of real biomasses with complex composition. The proof of concept is provided by bio-oil production from (i) Dried Distiller s Grains with Solubles (DDGS), the results serving to illustrate catalyst performance, and (ii) spent coffee grounds, which exemplify constituent analysis of the as-produced bio-oil. Both studies were carried out under near-critical conditions using both homogeneous and heterogeneous catalysts. © 2010 American Chemical Society. Source

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