Papers by Tuomas Koiranen
Chemical Engineering and Processing, Sep 1, 2022
A sorption-enhanced process for hydrogenation of CO 2 to methanol was designed and investigated b... more A sorption-enhanced process for hydrogenation of CO 2 to methanol was designed and investigated by mathematical modelling and techno-economic analysis. The modelling methodology combined dynamic modelling of the cyclic reactor operation with pseudo-steady state modelling of the overall process. With continuous adsorption of water in the sorption-enhanced process, highly pure methanol (>99%) was produced without downstream distillation. The dynamic reactor cycle was designed and optimized to maximize the methanol production rate. The cycle and the process were modelled in two reactor configurations: adiabatic and isothermal. Under the default cost assumptions for the raw materials (CO 2 50 €/t, hydrogen 3000 €/t) the adiabatic configuration was found more competitive in terms of the overall methanol production cost, at 1085 €/t compared to 1255 €/t for the isothermal case. The cost estimate for the adiabatic case was found comparable to a reference process representing conventional CO 2 hydrogenation to methanol (1089 €/t). In addition to the methanol process, the developed modeling method has potential in the design of other sorption-enhanced processes.
International Journal of Chemical Engineering and Applications, Feb 1, 2017
Hydrodynamic and mass transfer characteristics of an annulus-rising airlift reactor (AR_ALR) were... more Hydrodynamic and mass transfer characteristics of an annulus-rising airlift reactor (AR_ALR) were investigated with experimental and CFD simulation methods. An Eulerian model with two bubble phases was developed to simulate the AR_ALR in three circulation flow regimes. 3D steady state CFD simulations were performed under different gas superficial velocities (U g). Good agreements on gas holdup and volumetric mass transfer coefficient were obtained over the range of the studied U g. The simulated averaged liquid velocities in AR_ALR with different scales were compared and accounted for the influence of reactor scale on gas holdup. The three flow regimes in AR_ALR were captured well and are similar to those observed in experiments. The developed CFD model can be used to predict the hydrodynamics and mass transfer in AR_ALRs with different scales.
Sorption enhanced carbon dioxide hydrogenation to methanol: Process design and optimization
Chemical Engineering Science, Apr 1, 2022
Mass transfer efficiency comparison of air-lift reactor, stirred tank and stirred air-lift reactor
Journal of Advanced Chemical Engineering (Print), Nov 29, 2017
Journal of thermodynamics & catalysis, 2016
Climate and biodiversity impacts of low-density polyethylene production from CO2 and electricity in comparison to bio-based polyethylene
Science of The Total Environment, Jul 1, 2023
Frontiers in Energy Research, Feb 18, 2022
In order to limit climate change, fast greenhouse gas reductions are required already before 2030... more In order to limit climate change, fast greenhouse gas reductions are required already before 2030. Ethanol commonly produced by fermentation of sugars derived either from starchbased raw material such as corn, or lignocellulosic biomass is an established fuel decarbonizing the transport sector. We present a novel selective and flexible process concept for the production of ethanol with electricity and lignocellulosic biomass as main inputs. The process consists of several consecutive steps. First synthesis gas from gasification of biomass is purified by filtration and reforming and fed to methanol synthesis. The produced methanol is fed to acetic acid synthesis, together with a carbon monoxide-rich stream separated from the synthesis gas by membranes. Finally, acetic acid is hydrogenated to yield ethanol. With the exception of acetic acid hydrogenation, the overall process consists of technically mature subprocesses. Each process step was modelled in Aspen Plus to generate the mass and energy balances for the overall process. Additionally, the CO 2 emissions and economic feasibility were assessed. Three separate cases were investigated. In the first two cases, the syngas carbon (CO and CO 2) was split between methanol and acetic acid synthesis. The cases included either allothermal (case A) or electrically heated reforming (case B). In case C, maximum amount of CO was sent to acetic acid synthesis to maximize the acetic acid output, requiring a small additional carbon dioxide input to methanol synthesis. In all cases, additional hydrogen to methanol synthesis was provided by water electrolysis. Each case was designed at biomass input of 27.9 MW and the electrolyzer electricity requirement between 36 and 43.5 MW, depending on the case. The overall energy efficiency was calculated at 53-57%, and carbon efficiencies were above 90%. The lowest levelized cost of ethanol was 0.65 €/l, at biomass cost of 20 €/MWh and electricity cost of 45 €/MWh and production scale of approximately 42 kt ethanol per year. The levelized cost is competitive with the current biological route for lignocellulosic ethanol production. The ethanol price is very sensitive to the electricity cost, varying from 0.56 to 0.74 €/l at ±30% variation in electricity cost.
Energy and Environmental Science, 2023
Following current trends, the global chemical industry is set to become the largest consumer of f... more Following current trends, the global chemical industry is set to become the largest consumer of fossil fuels. Among energy intensive industries, the chemical industry is one of the most challenging to defossilise due to the abundance of cheap fossil fuel-feedstocks and it is currently responsible for roughly 3% of global anthropogenic CO 2 emissions. Unlike other energy-intensive industries, the chemical industry cannot be made fully sustainable directly with renewable electricity and green electricity-based hydrogen (e-hydrogen). Therefore, new green carbon feedstocks must be developed to defossilise the production of large volume organic chemicals. The most promising green carbon feedstocks are electricity-based methanol (e-methanol) and biomass-based methanol (bio-methanol), which can be used directly or as a feedstock for olefin and aromatic production. Increased recycling of plastics will reduce the amount of primary feedstock that will be required for chemical production. To investigate the energy and feedstock requirements for a global defossilisation of chemical production, scenarios are developed that reach net-zero emissions by 2040, 2050, and 2060 compared to business-as-usual conditions to 2100. High and low biomass feedstock variations are included to investigate the potential of biomass feedstocks in the future chemical industry, which are limited due to strict sustainability criteria. The results suggest that the chemical industry could become the largest e-hydrogen consumer, with a demand ranging from 16 100 to 23 100 TWh H2,LHV in 2050. High shares of electricity-based chemicals (e-chemicals) were found to provide the lowest annualised costs, suggesting that an e-chemical transition pathway may be the most economically competitive pathway to defossilise the global chemical industry. Broader context While the defossilisation of energy systems is well understood, the decoupling of fossil fuels from the chemical industry has often been overlooked, due to the abundance of cheap fossil feedstocks, which are used to produce plastics, fertilisers, pesticides, fibres, and personal care and consumer products, among other ubiquitous chemicals. The key challenge with the defossilisation of the chemical industry is the requirement of carbon-based feedstocks, which cannot be directly substituted with renewable electricity. Chemical demand is also expected to grow rapidly in the coming decades, and, without major disruption to feedstocks, could become the largest driver in oil consumption. Renewable electricity-and biomass-based feedstocks have been suggested to substitute fossil feedstocks; however, there is a knowledge gap in the energy system requirements to completely replace fossil feedstocks. This research presents scenarios for the complete defossilisation of global chemical feedstocks from 2020 to 2100 using a high geographical resolution of 145 regions. The results of this study found that the complete defossilisation of chemical production applying high levels of power-to-chemicals, in tandem with increased plastic recycling, will lead to the lowest annualised costs by 2050.
Separation and Purification Technology, 2020
A continuously operated CO2 capture unit, based on absorption in a membrane contactor and lowtemp... more A continuously operated CO2 capture unit, based on absorption in a membrane contactor and lowtemperature vacuum desorption, is demonstrated. The major advantage of membrane contactors is their high specific interfacial area per unit volume. The unit is designed to be modular to allow different absorption membrane modules and stripping units to be tested, with the aim of capturing CO2 from simulated flue gases at concentrations down to the ambient concentration. In addition, desorption can be performed under vacuum to improve the desorption efficiency. The experimental unit incorporates comprehensive measurements and a high level of automation, with heat integration and continuous measurement of electricity consumption providing real-time estimates of the energy consumed in the capture process. In preliminary tests, the results of which are described herein, a 3M Liqui-Cel™ polypropylene hollow-fiber membrane module and a glass vacuum chamber were used for absorption and desorption, respectively, along with a potassium glycinate amino acid salt absorbent solution. This solution has high surface tension and is fully compatible with the polypropylene membrane unit used. In preliminary tests, the highest observed CO2 flux was 0.82 mol m-2 h-1 , with a CO2 product purity of above 80%. The calculated overall mass transfer coefficient was comparable to reference systems. The performance of the unit in its current setup was found to be limited by the desorption efficiency. Due to the low desorption rates, the measured specific energy consumption was exceedingly high, at 4.6 MJ/mol CO2 (29.0 MWh/t) and 0.8 MJ/mol CO2 (5.0 MWh/t) of heat and electricity, respectively. Higher desorption temperatures and lower vacuum pressures enhanced the desorption efficiency and reduced the specific energy consumption. The energy efficiency could be improved via several methods in the future, e.g., by applying ultrasound radiation or by replacing the current vacuum chamber stripping unit with a membrane module or some other type of desorption unit.
International Journal of Greenhouse Gas Control, Jul 1, 2020
Mass transfer performance of a polypropylene hollow-fiber membrane contactor as part of a continu... more Mass transfer performance of a polypropylene hollow-fiber membrane contactor as part of a continuously operated CO2 capture unit with amino acid salt (potassium glycinate) absorbent and vacuum solvent regeneration was studied. The effects of key operating parameters on the absorption mass transfer characteristics were explored. Without vacuum stripping, absorption rate was found to be limited by low CO2 desorption efficiency from the loaded absorbent solution in the stripping unit, resulting in high solvent CO2 loadings and limited chemical absorption rates. Introduction of vacuum stripping greatly improved desorption performance, resulting in improved steady-state absorption performance. The overall mass transfer coefficient increased at higher stripping temperatures and lower vacuum pressures in the range of 60-80 °C and 300-800 mbar (abs). The overall mass transfer coefficient increased with increasing liquid flow rate, and the highest value reached was 1.8 • 10-4 m s-1. The individual mass transfer coefficients in absorption were calculated based on mass transfer correlations and experimental data, including estimation of the enhancement factor for chemical absorption. The overall mass transfer resistance was found to be dominated by the liquid-side resistance, at almost 90 % of the total resistance. The estimated membrane mass transfer coefficient was low compared to a theoretical value assuming non-wetted operation, suggesting potential partial wetting of the membrane. Stable performance of the unit and the membrane contactor was demonstrated during a stability test with over 30 hours of operation.
Insights into the Application of Ultrasound Tomography in the Precipitation of Calcium Carbonate
Chemical Engineering & Technology, Jul 28, 2023
The application of an ultrasound tomography (UST) system in a liquid‐phase reactive crystallizati... more The application of an ultrasound tomography (UST) system in a liquid‐phase reactive crystallization process is reported. The measurement system was applied to precipitated calcium carbonate processing where liquid Na2CO3 was added to a CaCl2 solution. Analysis of the measured sound velocity signals from the experiments demonstrated a clear change in the average time‐of‐flight (TOF) delay signals, indicating the detection of the onset of the precipitation and the formation of the microcrystalline stable phase of calcite. Moreover, spatial‐centric TOF signals from the tomographic images were associated with an increase in the overall suspension density. These findings highlight the potential of the UST measurement system for studying the solidification phenomenon during CaCO3 precipitation.
Assessment of electrified ethylene production via biomass gasification and electrochemical CO reduction
Frontiers in Energy Research, Apr 13, 2023
The chemical industry needs new methods for sourcing carbon-containing feedstocks from renewable ... more The chemical industry needs new methods for sourcing carbon-containing feedstocks from renewable sources to decrease CO2 emissions and reduce reliance on fossil fuels. Ethylene, a crucial base chemical used for making polymers and ethylene oxide, is primarily produced through steam cracking of fossil feedstocks. However, an evolving technology is the electrochemical reduction of CO2 or CO to produce ethylene. The study assesses the environmental, economic and energetic performance of a new biomass-based process that produces ethylene based on the electrochemical reduction of CO. The results are based on mass and energy balances from process simulation. The CO is produced by either gasification of biomass or combustion of biomass with CO2 capture and CO2 electrolysis. Besides ethylene, the process produces acetic acid, ethanol, oxygen and hydrogen as by-products which are purified and sold. The annual output varies between 36 and 68 kt ethylene with a biomass input of 157 kt. The levelized cost of ethylene ranges from 3,920 to 7,163 €/t with the gasification routes being the most cost-effective. The ethylene price is heavily dependent on electricity price, current density, operating voltage, and by-product prices. The carbon efficiency of the gasification-based routes is lower (64%) than the combustion-based routes (85%–86%). However, the energy efficiency is higher for the gasification-based routes (42%) compared to the combustion-based routes (28%). Conversion of ethanol to ethylene increases the ethylene yield with minimal impacts on the ethylene price. In terms of CO2 emissions, the gasification-based routes show lower emissions. Scenarios using wind power show a significant emission reduction potential compared to fossil products.
Frontiers in chemical engineering, Aug 31, 2022
CO 2 absorption into aqueous potassium glycinate in a polypropylene membrane contactor was modell... more CO 2 absorption into aqueous potassium glycinate in a polypropylene membrane contactor was modelled using two alternative models: a 1D model and a 1D-2D model considering axial diffusion in the liquid phase. Models were fitted to experimental data using various fitting parameters, which were compared. Experiments were carried out under industrially relevant conditions characterized by CO 2-loaded absorbent entering the contactor and high degree of reactant conversion over the contactor. The experiments and models were developed to specifically investigate the effect of changes in solution CO 2 loading at contactor inlet. This is a key issue rarely reported in the literature, especially for amino acid salt solutions. Unexpectedly, the 1D model was found to explain the experimental results more accurately compared to the more complex 1D-2D model. This was the case for the base models, using only the membrane mass transfer coefficient as a fitting parameter, and the final models introducing secondary fitting parameters. The 1D model was found to show the best experimental fit following fitting of the equilibrium constant used in prediction of the enhancement factor. The 1D-2D model showed the best fit following correction of potassium glycinate diffusivity as a function of solution CO 2 loading. The 1D approach was found to result in a computationally effective model with good fit to the present experimental data. This model provides a good basis for further development and could be considered for use in contactor design and optimization studies. It is suggested that various model simplifications led to inability of the 1D-2D model to accurately predict the experimental results.
CDF Simulation of sucrose crystallization in laboratory crystallizer
Computer Aided Process Equipment Selection and Design Engineering Techniques Using Knowledge Engineering Techniques
This research work presents a feasibility study to demonstrate the application of Electrical Resi... more This research work presents a feasibility study to demonstrate the application of Electrical Resistance Tomography and transmission-based Ultrasound Computed Tomography for monitoring and control of micronsized calcium carbonate crystallization process. Herein, precipitated calcium carbonate production is bind to a carbon dioxide absorption process based on hollow-fiber membrane contactor. ERT acquisition system is equipped with 16 electrodes with operating frequency of 156 KHz and image capturing frame rate of 2 Hz. The ultrasound tomography equipment consists of 32 piezoelectric transducers at a frequency of 200 KHz. These sensors are sensitive to changes in suspension density and conductivity. Furthermore, a process control framework is developed by utilizing the fundamental relations of settling velocity of particles. Through simulations in the LabVIEW software, the PI-based feedback controller demonstrates a possibility of setpoint tracking by manipulating the control variable (mixing speed). Upon further investigations, this approach can be used as a multi-dimensional process analytical technology tool for quality assurance and malfunction diagnosis when out-of-specification events occur throughout the entire process.
Membrane for CO2 separation
Emerging Carbon Capture Technologies
Application of novel big data processing techniques in process industries
International Journal of Computer Applications in Technology
Modern process engineering industry offers great opportunities for harvesting tremendous amounts ... more Modern process engineering industry offers great opportunities for harvesting tremendous amounts of data, both structured and unstructured. However, significant volumes of information as well as frequently encountered inconsistencies, missing values and other discrepancies render data processing with traditional tools rather inefficient. New software solutions are being constantly developed to address this challenge, yet, as regards analytics of actual industry related data, adaptation of these instruments has been comparatively limited so far. Consequently, within the limits of this work, applicability of novel analytical instruments in the context of process engineering industry is studied for both structured and unstructured data processing. In the former case, the data describing the copper matte smelting process is analysed focusing on identification of interdependencies between key process parameters and products' properties, while in the latter case, a collection of relevant scientific articles is investigated with a view to extracting key concepts and determining major relations among them.
Insights into carbon production by CO2 reduction in molten salt electrolysis in coaxial-type reactor
Journal of Environmental Chemical Engineering, 2022
TOMOCON: A Marie Skłodowska-Curie European Training Network on Tomography-based Control in Industrial Processes [in press]
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Papers by Tuomas Koiranen