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Studying salt solutions near the critical point of water using high pressure calorimetry and in-situ X-ray absorption spectroscopy

English title Studying salt solutions near the critical point of water using high pressure calorimetry and in-situ X-ray absorption spectroscopy
Applicant Vogel Frédéric
Number 132320
Funding scheme Project funding (Div. I-III)
Research institution Allgemeine Energieforschung Paul Scherrer Institut
Institution of higher education Paul Scherrer Institute - PSI
Main discipline Chemical Engineering
Start/End 01.10.2011 - 30.09.2015
Approved amount 373'012.00
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All Disciplines (2)

Discipline
Chemical Engineering
Physical Chemistry

Keywords (5)

hydrothermal; salt precipitation; ion pairs; phosphates; sulfates

Lay Summary (English)

Lead
Lay summary

Chemistry near the critical point of water (647 K, 22.1 MPa) is of fundamental interest for geochemical processes as well as for some novel waste and energy conversion technologies. Examples for such processes are Supercritical Water Oxidation (SCWO) and the hydrothermal gasification of biomass to produce methane/hydrogen mixtures.

Residual biomass often contains high amounts of water that would require a lot of energy to be removed completely before processing. Hydrothermal processing in an aqueous environment does not require dry biomass and has been suggested as having a great potential for producing biofuels and biochemicals from various types of biomass. Several recent reviews have identified salt handling as a major critical issue for the development of viable technologies. Our motivation is to understand salt formation, precipitation, and recovery in hydrothermal systems relevant for, but not restricted to, technical processes such as hydrothermal gasification of biomass or Supercritical Water Oxidation. In particular, we would like to be able to understand and improve the separation of salts in our hydrothermal gasification process, based on fundamental knowledge of salt formation and precipitation at the molecular level.

The aim of this project is to investigate the basic mechanisms of salt particle formation in aqueous solutions of phosphates and sulfates at ambient conditions as well as in near- and supercritical water. In detail, the structure of solvated ions including their hydrate shells and the interaction between anion and cation (ion pair formation) shall be investigated.

Several methods (high pressure differential scanning calorimetry, X-ray absorption spectroscopy) shall be applied in order to characterize the temperature and pressure of phase transitions and salt precipitation of binary and ternary water-salt systems (e.g. K2SO4 and K3PO4). The structure of salt-water complexes and ion pairs will be investigated by in-situ X-ray absorption spectroscopy using the high-pressure reaction cell developed in the previous project. The experiments will be carried out at the newly constructed PHOENIX beamline at the Swiss Light Source (SLS).

The results of the planned project shall help to elucidate the relationship between the structure of ion-water complexes and hydrated ion pairs or clusters in solution and the structure of nuclei which will start the crystallization process and may define the physical properties of the precipitates. An anticipated application of this knowledge is the improvement of a novel process for converting biomass to methane in supercritical water under development at the Paul Scherrer Institut.

Direct link to Lay Summary Last update: 21.02.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
A Novel Salt Separator for the Supercritical Water Gasification of Biomass
Reimer Joachim, Peng Gaël, Viereck Sebastian, De Boni Erich, Breinl Jakob, Vogel Frédéric (2016), A Novel Salt Separator for the Supercritical Water Gasification of Biomass, in J. Supercritical Fluids, 117, 113-121.
Speciation and Structural Properties of Hydrothermal Na‐K‐SO4 Solutions Studied by Molecular Dynamics Simulations
Reimer Joachim, Steele-MacInnis Matthew, Vogel Frédéric (2016), Speciation and Structural Properties of Hydrothermal Na‐K‐SO4 Solutions Studied by Molecular Dynamics Simulations, in ChemPhysChem, 17, 1446-1453.
Hydrothermal properties of the COS/D2 water model: A polarizable charge-on-spring water model, at elevated temperatures and pressures
M. Steele-MacInnis J. Reimer S. Bachmann (2015), Hydrothermal properties of the COS/D2 water model: A polarizable charge-on-spring water model, at elevated temperatures and pressures, in RSC Advances, 5, 75846-75856.
Ion Association in Hydrothermal Sulfate Solutions, studied by Modulated FT-IR-Raman and Molecular Dynamics
J. Reimer M. Steele-MacInnis J.M. Wambach F. Vogel (2015), Ion Association in Hydrothermal Sulfate Solutions, studied by Modulated FT-IR-Raman and Molecular Dynamics, in J. Phys. Chem. B, 19(30), 9847-9857.
Combined Sulfur K‑Edge XANES−EXAFS Study of the Effect of
Pin Sonia, Huthwelker Thomas, Brown M. A., Vogel Frédéric (2013), Combined Sulfur K‑Edge XANES−EXAFS Study of the Effect of, in J. Phys. Chem. A, 117, 8368-8376.
High Pressure Differential Scanning Calorimetry of the Hydrothermal Salt Solutions K2SO4-Na2SO4-H2O and K2HPO4-H2O
Reimer Joachim, Vogel Frédéric (2013), High Pressure Differential Scanning Calorimetry of the Hydrothermal Salt Solutions K2SO4-Na2SO4-H2O and K2HPO4-H2O, in RSC Advances, 3, 24503-24508.
Influence of Anions and Cations on the Phase Behavior of Ternary Salt Solutions Studied by High Pressure Differential Scanning Calorimetry
J. Reimer F. Vogel, Influence of Anions and Cations on the Phase Behavior of Ternary Salt Solutions Studied by High Pressure Differential Scanning Calorimetry, in J. Supercritical Fluids.

Collaboration

Group / person Country
Types of collaboration
Ch. Ludwig (PSI and EPFL) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Research Infrastructure
J. L. Fulton (Pacific Northwest National Laboratory) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
M. Steele-McInnis (Univ. Arizona) United States of America (North America)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
T. Driesner (ETH Zürich) Switzerland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
M. Ammann (PSI) Switzerland (Europe)
- Research Infrastructure

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
11th International GeoRaman Conference Talk given at a conference Modulated FT-IR-Raman Spectroscopy of Hydrothermal Salt Solutions 15.06.2014 St. Louis, Missouri, United States of America Vogel Frédéric; Reimer Joachim;
JUM@P ’13, Joint Users’ Meeting Poster In-situ X-ray Absorption Spectroscopy to study the Structure of Hydrothermal Aqueous Sulfate Solutions 18.09.2013 Villigen PSI, Switzerland Reimer Joachim;
16th International Conference on the Properties of Water and Steam Talk given at a conference Biomass related Salt Solutions at Hydrothermal Conditions: Investigations with Isochoric Differential Scanning Calorimetry 01.09.2013 Greenwich, Great Britain and Northern Ireland Reimer Joachim;
3rd Workshop on the simultaneous combination of spectroscopies with x-ray absorption, scattering and diffraction techniques Poster New high temperature - high pressure XAS cell to study salt precipitation at and near supercritical conditions of water 04.07.2012 Zürich, Switzerland Pin Sonia;
Summer School of Calorimetry Poster Biomass-related Salt Solutions at Hydrothermal Conditions - Investigation with High Pressure Differential Scanning Calorimetry 10.06.2012 Lyon, France Reimer Joachim;


Awards

Title Year
BIAPWS Student Award in Memory of the contributions of Geoff Bignold to the study of power plant chemistry 2013

Associated projects

Number Title Start Funding scheme
183663 Behavior of sulfur in biomass under hydrothermal conditions: removal strategies for catalytic processes 01.02.2020 Japan
172624 Catalytic biomass conversion under extreme conditions: improving the Ru-based catalyst 01.09.2017 Project funding (Div. I-III)
130615 Catalysis Under Extreme Conditions: in situ Studies of the Reforming of Organic Key Compounds in Supercritical Water 01.08.2010 Project funding (Div. I-III)
109572 Salt Particle Formation in Near- and Supercritical Water 01.08.2006 Project funding (Div. I-III)
139563 Preparation of a Hydroxylapatite supported Ruthenium Catalyst by a Coprecipitation Method 01.10.2011 International short research visits

Abstract

Chemistry near the critical point of water (Tc = 647 K, pc = 22.1 MPa) is of fundamental interest for geochemical processes as well as for some novel waste and energy conversion technologies. Examples for such processes are Supercritical Water Oxidation (SCWO) and the hydrothermal gasification of biomass to produce methane/hydrogen mixtures. Residual biomass often contains high amounts of water that would require a lot of energy to be removed completely before processing. Hydrothermal processing in an aqueous environment does not require dry biomass and has been suggested as having a great potential for producing biofuels and biochemicals from various types of biomass. Several recent reviews have identified salt handling as a major critical issue for the development of viable technologies. Our motivation is to understand salt formation, precipitation, and recovery in hydrothermal systems relevant for, but not restricted to, technical processes such as hydrothermal gasification of biomass or Supercritical Water Oxidation. In particular, we would like to be able to understand and improve the separation of salts in our hydrothermal gasification process, based on fundamental knowledge of salt formation and precipitation at the molecular level.The aim of this project is to investigate the basic mechanisms of salt particle formation in aqueous solutions of phosphates and sulfates at ambient conditions as well as in near- and supercritical water. In detail, the structure of solvated ions including their hydrate shells and the interaction between anion and cation (ion pair formation) shall be investigated. This proposal is an extension of a previous SNF project (200021-109572). In that project, the conditions at which salt precipitation around the critical point of water (Tc = 647 K, pc = 22.1 MPa) occurred were investigated with different in-situ methods. Specifically, a dedicated X-ray absorption cell was constructed allowing XAS experiments at low energies (phosphorus K-edge, 2145 eV) in near- and supercritical water. Measurements at such low energies in near- and supercritical water still represent a significant challenge.Several methods (high pressure differential scanning calorimetry, EXAFS) shall be applied in order to characterize the temperature and pressure of phase transitions and salt precipitation of binary and ternary water-salt systems (e.g. K2SO4 and K3PO4). The structure of salt-water complexes and ion pairs will be investigated by in-situ X-ray absorption spectroscopy using the high-pressure reaction cell developed in the previous project. The experiments will be carried out at the newly constructed PHOENIX beamline at the Swiss Light Source (SLS).The results of the planned project shall help to elucidate the relationship between the structure of ion-water complexes and hydrated ion pairs or clusters in solution and the structure of nuclei which will start the crystallization process and may define the physical properties of the precipitates. An anticipated application of this knowledge is the improvement of a novel process for converting biomass to methane in supercritical water under development at the Paul Scherrer Institut.
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