Trondheim, Norway




Absorption laboratories at NTNU - SOLVENT CHARACTERIZATION (• Kinetic studies • Solvent degradation • Thermodynamic studies • Lab pilot)

The solvent characterization infrastructure is can be used for thermodynamic, kinetic and solvent degradation studies. Lab pilot allows testing of new solvents.


Understanding the chemical and physical equilibria (VLE) behavior of the solvent system is maybe the most important data needed for process development and process simulations. The setups available in this infrastructure are

  • Low and medium pressure VLE setups: There are, in total, three equipment. One of the equipment, operating between 25 and 80oC, allow direct measurement of the amount of CO2 in the gas phase. In the other setups, the CO2 amount absorbed and present in the gas phase is based on mass balance. The two setups are suitable for measurements up 5 bars and 140oC. The choice of equipment is dependent on the solvent, as well as temperatures and pressures used. The setups require solvent amounts between 150ml to 500 ml.

  • High-pressure VLE setup: This setup allows measurements up to 200bar and 200oC. The equipment is typically used for high-pressure applications or for applications where methane solubility is of interest. Both liquid and gas phases are sampled and analyzed with GC. The volume of the cell is ~60ml, and the minimum operating pressure is 5-10 bar. The high pressures make the experiments are very time-consuming, and the costs of the intensive training required have to be covered separately.

  • Calorimeters: We have two calorimeters for the heat of absorption of CO2 studies. Furthermore, one of the calorimeters allows for the heat of crystallization/dissolution studies. Both calorimeters can be used up to 10bar, but with some modifications, higher pressures can be reached. The volumes of the calorimetric reactors are 2L and 250 cm3.

We have basic analytical possibilities (amine and CO2 titration methods and TOC/TIC/NT) available in our labs. Additionally, we have the equipment to measure physical properties like density and viscosity.


Absorption kinetics are crucial when estimating the height of the absorber and during process simulations. Additionally, to absorption rate data, data for physical properties are needed to model the kinetics. Therefore, this facility offers

• Three setups for measurement of kinetics

• Apparatuses for viscosity and density measurements

• The possibility to measure the physical solubility of CO2 using N2O analogy.

Measurement of absorption kinetics can be performed with three different setups: a string of discs, a wetted wall column, and a stirred cell. Both CO2-loaded and unloaded solutions can be measured. The amount of solvent needed is large for the string of discs and the wetted wall column.

All the kinetic apparatuses can be used with CO2-loaded and unloaded solutions. The wetted wall column and the string of discs can operate up to 80oC at atmospheric pressure. The stirred cell extends the experimental range to elevated pressures. Additionally, the measurement of viscosity, density can be performed at the conditions used to measure the kinetics. Finally, N2O solubility into the studied solvent can be measured to determine the physical solubility of CO2 using N2O analogy.


Solvent degradation and corrosion can be a show-stopper for process and solvent development. The amount of degradation is one of the factors that dictate the need for solvent make-up. In addition to degradation contributing to the higher cost of solvent make-up, some of the degradation compounds formed have unwanted properties like high corrosivity or high volatility. For example, volatile degradation compounds might escape from the absorber and increase the process's environmental impact if not adequately controlled. Furthermore, a fundamental understanding of corrosion and degradation is the key when developing countermeasures for degradation. Understanding the connection of different process parameters and degradation compounds is, therefore, of high interest.

This laboratory includes three apparatuses.

  • The oxidative degradation in a batch reactor is suitable for degradation studies at absorber temperatures (45-60oC). The setup is ideal for testing of the effect of loading and oxygen concentration on degradation.

  • Thermal degradation tests are performed in metal cylinders up to 150oC. The amount of CO2 and access to metals can be controlled by placing a glass tube inside the cylinder. These tests also give some indication of the corrosivity of the solvent.

  • With the screening apparatus for oxidative degradation, it is easy to test degradation and corrosion inhibitors, or degradation with varying solvent concentration.

Post-combustion Lab pilot (NTNU/SINTEF)

The pilot was built in 1998 and upgraded in 2004. The gas treating capacity of the pilot plant is approximately 150 m3/h. The absorber (ID = 0.15m) has a packing height of 4.23m, whereas 3,57m of packing is available in the stripper section (ID 0.1m). The pilot is fully automated with continuous logging of the liquid and gas flows, the temperature profiles in the packed columns (seven probes in the absorber and five probes in the stripper), the CO2 concentrations in and out of the absorber, the reboiler heat duty and temperatures and pressures in the pipes. The absorber is connected to a water wash section with a height of 2.1m and an internal diameter of 0.15m. The total amount of liquid solution needed for operation is ~180l. The pilot is operated continuously (24-hours), and no operator is needed present in the evenings/nights.

The plant is specially designed for solvent testing in post-combustion and can be used for

  • testing of new potential amines

  • testing degradation in the long term campaigns (it is possible to add NO/NO2 into the gas phase)

  • water wash experiments

  • testing of new technics related to emission control.

State of the Art, uniqueness & specific advantages


Scientific Environment

  • The solvent characterization infrastructure covers vapor-liquid equilibrium, the heat of absorption, absorption kinetics, and solvent degradation studies.

  • The experimental apparatuses have been used in EU-funded projects like CASTOR, CESAR, DeCarbit, ENGAS, iCAP, HiperCAP, and REALISE. In the last eight years, more than 50 peer-reviewed journal publications present data from these installations.

  • We have basic analytical possibilities (amine and CO2 titration methods and TOC/TIC/NT) available in our labs. The analytical laboratory at SINTEF Industry (Biotechnology and Nanomedicine

  • department), located on the same campus, offers services to analyse for degradation products.

  • The setups are used by master and PhD-students as well as researchers. We have a close co-operation with the Department of Process Technology in SINTEF Industry. Through the exchange of Ph.D. students and research personnel, we currently collaborate with CSIRO (Australia) and the Department of Chemical Engineering, University of Austin, Texas.  


Operating by


Norwegian University of Science and Technology (Norges teknisk-naturvitenskapelige universitet)
CAPTURE technologies:
UTILISATION technologies:
Smart integrations with carbon capture and re-use into valuable products
Research Fields:
Kinetics, Chemistry/Geochemistry, Thermodynamics
Facility's fact sheet

Location & Contacts

Trondheim, Norway
Hanna Knuutila
RICC Contacts - Secondary contact
Morten Grønli

Facility Availability

Unit of access (UA)
Availability per year (in UA)
Minimum 8 weeks
Duration of a typical access (average) and number of external users expected for that access
Typically minimum 4 weeks.

Quality Control / Quality Assurance (QA)

Activities / tests / data are
State of Quality: We are following local HSE routines. More information: https://www.ntnu.edu/nv/about-us/hse and https://innsida.ntnu.no/wiki/-/wiki/English/HSE+Policy
Institution QA Webpages

Operational or other constraints

Specific risks:
All activities: All chemicals and activities will be risk assessed. The risk assessment can lead to higher costs due to increased HSE-requirement. Local HSE rules and risk assessment will regulate what chemicals can be used. Pilot studies: NTNU/SINTEF will approve each solvent planned to be tested to ensure safe working environment for all. The solvent has to pass corrosion tests. An operator from either NTNU/SINTEF will be needed to ensure the safe operation of the pilot.
Legal issues

CCUS Projects

EU-Funded CCUS Projects
ERA-NET Accelerating CCS Technologies initiative,
ERA-NET Accelerating CCS Technologies initiative
National Fund

Selected Publications

Journal of Chemical and Engineering Data;Volum 67.(1) s. 159-166 (2021)
Vapor–liquid equilibria data for 2-piperidineethanol and 1-(2-hydroxyethyl)pyrrolidine in aqueous solutions and a UNIQUAC model representation.
Hartono, Ardi; Nøkleby, Christina; Kim, Inna; Knuutila, Hanna K
Fluid Phase Equilibria;Volum 550. s. (2021)
New solubility and heat of absorption data for CO2 in blends of 2-amino-2-methyl-1-propanol (AMP) and Piperazine (PZ) and a new eNRTL model representation.
Hartono, Ardi; Ahmad, Rafiq; Svendsen, Hallvard Fjøsne; Knuutila, Hanna K.
International Journal of Greenhouse Gas Control,109,103398, (2021)
Signs of alkylcarbonate formation in water-lean solvents: VLE-based understanding of pKa and pKs effects.
Wanderley, Ricardo R., Karen Karoline Høisæter, and Hanna K. Knuutila.
Chemical Engineering Science ;Volum 10. (2021)
Addition of stable salts reduced oxidative degradation of monoethanolamine (MEA).
Buvik, Vanja; Ramos Wanderley, Ricardo; Knuutila, Hanna K.
Energy Fuels , 34, 7, 8552–8561 (2020)
Solubility and Heat of Absorption of CO2 into Diisopropylamine and N,N-Diethylethanolamine Mixed with Organic Solvents.
Wanderlay, R., Ponce, GJC., Knuutila HK.