Thermodynamics and Phase Behavior

Focus in the Wei Yan Group research centers on chemical thermodynamics and phase behavior with applications spanning a wide range of scientific disciplines and industrial processes. Central to these applications are phase transitions, component partitioning, and thermophysical properties, which govern system performance and behavior. Our current focus areas include carbon capture and storage (CCS) as well as hydrogen transport and storage. Our group develops robust and efficient algorithms for phase and chemical equilibrium calculations, delivering essential tools for modern compositional simulation and process modeling.

Research

With a focus on thermodynamics and phase behavior, our research activities integrate experimental measurements, thermodynamic modeling, and compositional simulation. Many scientific and technological challenges in carbon capture and storage and other decarbonization technologies are fundamentally related to thermodynamics. Key issues include high-pressure phase behavior, thermophysical properties, and multiphase equilibria involving chemical reactions.

Our thermodynamic research spans experimental investigation, thermodynamic modeling, and algorithm development. The integrated expertise enables us to address a range of critical challenges in the development and deployment of decarbonization technologies. Some selected research activities include phase behavior of CO2 with impurities, computational algorithms for the reactive-transport process in CO2 storage, impact of reactive and non-reactive impurities during CO2 injection, as well as Equilibrium calculation algorithms and thermodynamic models for CO2 capture simulation.

Simultaneously, we keep developing our core competences in algorithms for chemical and phase equilibrium, thermodynamic modeling of complex phase behavior, and experimental studies of equilibrium and thermophysical properties.

To learn more go to website of CERE.

 

 

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Profile Wei Yan

2017- Executive Editor for Journal of Natural Gas Science and Engineering

2014- Associate Editor for Journal of Petroleum Science and Engineering

2010- Senior Scientist at Center for Energy Resources Engineering, Department of Chemistry, Technical University of Denmark

2005-2010 Associate Professor at Department of Chemical Engineering, Technical University of Denmark

2001-2005 Research Assistant Professor at IVC-SEP at Department of Chemical Engineering, Technical University of Denmark

1999 Ph.D. in Chemical Engineering, University of Petroleum, China

Laboratory

Experimental study of high-pressure phase behavior: Our laboratory is equipped with state-of-the-art facilities for analyzing petroleum fluid composition, preparing high-pressure fluid samples, and conducting systematic phase behavior study of reservoir fluids or multicomponent mixtures. We can perform petroleum characterization using simulated distillation and true boiling point distillation. Most high-pressure facilities can operate up to 200 oC and 1500 bar. The high-pressure lab allows measurement of phase equilibrium including saturation points, organic deposits (wax and asphaltene), and various thermophysical properties (density, viscosity, and heat capacity).

Modeling of complex phase equilibrium: For complex mixtures and systems at extreme conditions, accurate description of phase equilibrium often require application of advanced thermodynamic models or further improvement of the modeling approach. Typical examples include high-pressure high-temperature reservoir fluids, steam/heavy oil/solvents systems, hydrocarbon mixtures in confined spaces.

Phase equilibrium calculation algorithms: Efficient and robust equilibrium calculation algorithms are indispensable to compositional simulations. We work on various phase equilibrium calculations in particular different flash-type problems. For instance, we work on multiphase isothermal flash, multiphase isenthalpic flash and other flash specifications. A recent focus is modified RAND and its variations, which can be applied to simultaneous chemical and phase equilibrium calculation and various flash specifications.

Oil production and underground CO2 storage: A strategic research area is petroleum production and underground CO2 storage. The two issues concern energy security and CO2 emission reduction, respectively, but they are also interrelated since both handle large scale underground processes. We are particularly interested in gas injection and other solvent injection technologies, development of challenging resources such as shale and HPHT reservoirs, and CO2 sequestration through EOR or in aquifers. We work on PVT experiment and modeling, reservoir simulation as well as flooding experiments.

Facilities

High-pressure PVT apparatus ST PVT 240/1500 FV

The PVT apparatus 240/1500 FV from Sanchez Technologies has a stainless-steel cell with a motor driven piston at one end to vary the cell volume precisely. It has a maximum volume of 240 cm³ and can operate up to 200°C and 150 MPa. There is a sapphire window at the other end of the cell which allows visual observation of all the space inside the cell. The sample inside the cell can be agitated by means of a mechanical stirrer attached to the head of the piston. The stirrer has retractable blades to reduce the dead volume of the PVT cell. The apparatus can be used for phase equilibrium and phase transition studies for CO2 capture and storage, petroleum PVT, and other high-pressure fluid mixtures in general.

The system is equipped with other supporting units: a recombination unit, a gas meter, a high-pressure pump with a filter for organic deposit study, a high-pressure capillary viscometer, a high-pressure vibrating tube density meter, and a Setaram C80 calorimeter. This allows for a systematic study of phase equilibrium and thermophysical properties (density, viscosity, heat properties).

High-pressure recombination unit with a volume of 1.5 L (up to 200°C and 150 MPa)
High-pressure recombination unit with a volume of 1.5 L (up to 200°C and 150 MPa)
Gas-oil-ratio unit with 5 L gas meter, cooling traps, and gas sampling bottles
High-pressure pump up to 200°C and 150 MPa (including a filtration system for studying organic deposits)
High-pressure capillary viscometer (up to 200°C and 150 MPa)
Anton Paar DMA HPM density meter (up to 200°C and 140 MPa)
Differential scanning calorimeter (Setaram C80) with self-designing high-pressure cells (up to 200°C and 150 MPa)
Physical distillation by FISCHER® LABODEST® HMS 500 AC

Research Projects

In the following you can find more information about the research groups current research projects.

The following projects are being worked on at the moment:

Objective:
The goal of CapSim is to develop precise and robust software tools for use in process simulators, applicable to both standard and innovative carbon capture processes. Additionally, the project investigates how inaccuracies in process design can affect subsequent stages in carbon capture and storage.

Approach:
CapSim aims to enhance CO2 capture simulation technology by concentrating on two main areas:

  • Enhancing the core multiphase reactive algorithm to efficiently and robustly manage complex reactions and multiphase equilibrium.
  • Integrating thermodynamics, kinetics, and transport phenomena more effectively into the simulation, highlighting their influence on the results.

CapSim addresses algorithmic and thermodynamic challenges in CO2 capture simulation using tools such as Aspen Plus, Pro/II, CO2SIM, and CAPCO2. The project aims to overcome issues related to acidic gases, speciation, reactions, and thermodynamics. It is organized into four work packages: tackling algorithmic challenges, developing thermodynamic models, addressing process uncertainties, and optimizing processes. Advanced algorithms like RAND are utilized, with a focus on robustness, efficiency, and accuracy.

Expected Impact/Output:
Capture simulation serves as a vehicle to scale various novel ideas to industrial implementation. Advancing key capture simulation technologies will facilitate the quicker adoption of new solvents and more reliable optimization towards lower energy consumption in capture processes. Since capture is the most expensive step in CCS and the bottleneck for the entire chain, these advancements are crucial.

 

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Antonio Cavalcante De Lima Neto

Antonio Cavalcante De Lima Neto PhD Student

Partners

Background
CO2 injection into geological formations triggers complex physical and chemical interactions at different time and length scales, which are critical to the evaluation of subsurface capacities, operational risks, and storage safety. Reservoir simulation is the central technology to analyze potential risks during the injection-period and to evaluate the long-term safety.

Some of the future CO2-storage projects are likely to inject over million tons CO2 per year to underground geological formations. The importance of de-risking the technology with the help of modern reservoir simulations thus becomes more pronounced. CO2 storage simulation provides a comprehensive tool to integrate information for de-risking injection and storage.

Objectives
The project will advance the simulation technology for geological CO2 storage and build a state-of-the-art simulator that can be used for evaluating both the injection and the post-injection periods and hereby helping an early decision on the implementation of CO2 storage and accelerating its implementation. The project will develop a CO2 storage simulation analysis that will be equipped with improved reliability and efficiency, suitable for risk evaluation of a larger variety of storage sites.

Expected Results

  • Develop a compositional simulator with multiphase geochemical reactions that is more robust and efficient than the existing CO2 storage simulators.
  • Couple the simulator with the post-injection simulator GEOS in collaboration that compositional and geochemical effects are accounted for in the post-injection analysis.
  • Improve the technical risk assessment during injection and the long-term safety evaluation by using more accurate reactive transport description.

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Maximilian Wirth

Maximilian Wirth PhD Student

Aliakbar Roozshenas

Aliakbar Roozshenas PhD Student Mobile: +45 52654764

Zhenjie Wang

Zhenjie Wang PhD Student

Partners
More partners

Background

The geological storage of carbon dioxide (CO2) is a pivotal technology in the portfolio of solutions aimed at mitigating climate change by reducing greenhouse gas emissions. However, the CO2 captured from industrial processes or directly from the atmosphere often contains impurities (denoted as X, which could be nitrogen, argon, methane, or other gases), and interacts with various in-situ fluids like brine and hydrocarbons when injected into geological formations. The phase behavior of these CO2+X mixtures is crucial for the efficient and safe storage of CO2, influencing factors such as the storage capacity of geological sites, the integrity of injection processes, and the long-term stability of stored CO2.

Despite extensive research into CO2 and its mixtures, the specific conditions encountered in geological storage—such as varying pressures, temperatures, and compositions—present unique challenges. There exists a significant amount of data and several models for CO2 systems, but these are often focused on pure CO2 or simple mixtures, not fully capturing the complexity of real-world CO2 streams with multiple impurities or the interaction with reservoir fluids. Furthermore, the integration of high-fidelity models into practical tools for simulation and analysis of CO2 storage scenarios remains limited. This gap hampers the accurate assessment of potential risks like pressure build-up, leakage, or chemical interactions within the storage site, which are vital for both operational safety and regulatory compliance. The current state of the art lacks a unified approach to systematically address these issues across different types of storage environments, from depleted oil and gas reservoirs to saline aquifers.

Objectives

  • Data and Model Synthesis: Compile and assess existing data and models on CO2+X phase behavior.
  • Experimental Insights: Gather essential experimental data on CO2 mixtures relevant to geological storage.
  • Model Enhancement: Develop improved models for CO2+X systems to better predict phase behavior.
  • Simulation Integration: Integrate these models into simulations for real-world CO2 storage scenarios.

Expected Results

  • Improved Risk Assessment: Tools and methodologies for better managing CO2 storage risks.
  • Standards Development: Establish industry standards for CO2 mixture behavior in storage settings.
  • Operational Efficiency: Enhance storage safety and capacity estimates, aiding in meeting climate goals.
  • Global Applicability: Provide insights that can be applied internationally, promoting wider CCS adoption.

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Sonja Smith

Sonja Smith Postdoc

Marc Cassiede

Marc Cassiede Postdoc Mobile: +33681835310

Omofolasewa Hillary Jayeola

Omofolasewa Hillary Jayeola PhD Student

Partners

Objective:
The objective of the DemoBECCS project is to utilize accurate and robust software tools for modeling and simulating the storage of biogenic CO2 in depleted oil reservoirs. This project also explores how impurities in biogenic CO2 impact storage mechanisms, capacity, and safety.

Approach:
The project aims to enhance CO2 storage simulation technology by focusing on two key areas:

  • Evaluating the impact of impurities on CO2 storage in depleted oil reservoirs with high water saturation.
  • Integrating thermodynamic modeling and flow simulations to analyze the interplay between multiphase equilibrium and multiphase flow.

The DemoBECCS project addresses the following challenges:

  • Interaction with remaining oil through thermodynamic modeling and flow simulations.
  • Geochemical reactions for salt precipitation due to evaporation or mineralization reactions.

This PhD project, a primary work package within DemoBECCS, collaborates with Chinese partners working on CO2 storage at a Chinese site. The Chinese partners will conduct flooding experiments to integrate their results into the modeling and simulation study.

Expected Impact/Output:
The project aims to demonstrate the feasibility of storing biogenic CO2 at the planned Nini storage site and similar locations. By advancing CO2 storage simulation technologies, the project will:

  • Improve the understanding of impurities in biogenic CO2 and their impact on storage capacity, injectivity, CO2 plume development, and storage mechanisms.
  • Facilitate the optimization of existing capture solvents and processes.
  • Support the development of new phase-change solvents.

Successful outcomes will contribute to the broader goal of implementing BECCS technology in Denmark and China, enhancing the viability of large-scale CO2 storage projects.

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Matin Bagheri

Matin Bagheri PhD Student

Partners

MISSION-CCS (Material Science Innovation for Accelerated, Sustainable and Safe Implementation of Carbon Capture and Storage) is a Marie Skłodowska-Curie Actions Doctoral Network (MSCA-DN) program that will provide a bespoke training environment for 13 Doctoral Candidate Researchers (DCRs), focussed on understanding and mitigating material degradation phenomena across the entire CCS chain. The interdisciplinary network consists of 16 internationally-leading organisations (consisting of 4 academic institutions (DTU, Univ. of Leeds, NTNU, and INSA Lyon) and 12 other associated members) across 7 countries, who are at the scientific forefront of combining material science, engineering, physics, chemistry and techno-economics to develop the next generation of research and innovation leaders in the field of CCS.

You can find further details on MISSION-CCS here: mission-ccs.eu

Contact

Wei Yan

Wei Yan Professor Phone: +45 45252379

Marc Cassiede

Marc Cassiede Postdoc Mobile: +33681835310

Ding Xiong

Ding Xiong PhD Student

Group members