Gas Stream Research Articles

Bio-engineering of carbon adsorbents to capture CO2 from industrial sources: The cement case

Pine cone leaves (PCL) and pine kernel shells (PKS), abundant by-products of the Spanish food industry, were selected as precursors for activated carbons (ACs) to adsorb CO2 selectively at industrial post-combustion capture conditions. The goal was to maximize the development of narrow microporosity in the final carbons to boost the CO2 adsorption capacity. We have designed kinetics and equilibrium of adsorption experiments with CO2/H2O/N2 on a selected AC derived from PCL in a thermogravimetric analyzer (TGA) at 50 °C and three partial pressures of CO2 to prove the suitability to capture CO2 from industrial off-gases. When humid flue gas streams were tested, competitive adsorption of CO2 and H2O occurred; however, the difference in the uptake rates favored CO2 adsorption in the early stages. The joint CO2 + H2O uptake was around 2 mmol g−1 at 50 °C in humid conditions, where CO2 reached the equilibrium uptake at the corresponding partial pressure for 15 and 32 vol% CO2 in the feed stream. Moreover, the dynamic performance was addressed by cyclic adsorption–desorption experiments representing different industrial post-combustion capture scenarios in a lab-scale fixed-bed rig. The selected AC showed a stable performance in adsorption-regeneration cycles and very remarkable CO2 capture capacity under dry conditions (up to 1.08 mmol g−1 at 50 ˚C for 30 vol% CO2). Kinetics analysis also supported the faster adsorption of CO2 under cement flue gas conditions.

Mathematical Modeling of Cryochemical Formation of Medicinal Substances in Nanoforms. The Role of Temperature and Dimensional Parameters

The work is aimed at creating a mathematical model of cryochemical synthesis of nanoforms of pharmaceutical substances. The therapeutic efficacy of pharmaceutical substances largely depends on the size and morphology of the particles. Reducing the particle size of pharmaceutical substances to nanoscale makes it possible to obtain highly effective drugs, which makes it possible to use smaller doses of drugs and, thus, reduce side effects and toxicity. Cryochemical synthesis is one of the most powerful methods for obtaining nanoforms of medicament. The method, which is completely new, is based on sublimation or evaporation of the initial pharmaceutical substance under high vacuum conditions and the introduction of the resulting vapors into an inert gas stream, followed by low-temperature condensation of the flow of molecules of the substance from the gas phase on the cooled surface. The first step in the mathematical modeling of cryochemical synthesis processes is the calculation of the temperature field in the carrier gas flow interacting with the cooled surface. For this purpose, a stationary equation of thermal conductivity with mass transfer is used for the one-dimensional case. We prove existence and uniqueness theorems of the solution. Analytical solutions of the equation for Dirichlet, Neumann and Robin boundary conditions are found.

Sulfur melt in Golovnin Caldera, Kunashir Island, Russia

The paper considers the formation of native sulfur and sulfides in the bottom sediments of volcanic lakes in the Golovnin Caldera. Our observations and microstructure studies indicate the presence of sulfur melt at the bottom of Kipyaschee Lake. Drops of this melt are carried to the surface of the lake as part of a light gray foam. The significant differences of sulfur spherules in the concentration of sulfide mineralization, in its composition, as well as in the presence or absence of numerous opal inclusions are most simply explained by the capture of droplets in various parts of the sulfur melt and their subsequent movement by a gas stream passing through the melt. The effusions of sulfur melt in 1979 are direct evidence of its existence. Molecular chemical modeling shows that the stability of sulfur condensate in the bottom sediments is controlled by two thermobaric surfaces. The upper is controlled by the beginning of water condensation and a wave of acidity, the lower by the beginning of sulfur condensation. Both surfaces are a consequence of the cooling effect of lake water, and when bottom sediments accumulate, they move following changes in the surface of the lake bottom. Elemental sulfur condensate is formed between these surfaces as a result of forced cooling of endogenous gas flows. This process is most active in crater depressions at the bottom of Golovnin Caldera lakes, where sulfidization of the sulfur melt occurs simultaneously with the condensation of sulfur itself. Gravitational deposition of sulfides in the sulfur melt leads to their enrichment of the root parts of crater depressions, where pyrite ore bodies are formed in real time.

Carbon dioxide and methane capture in metal-organic framework MIL-101(Cr) at high pressure

Due to the presence of high CO2 amounts in the natural gas stream, a variety of efforts have been employed in the search for more efficient materials for the separation of gaseous mixtures such as CO2/CH4. In this article, a metal-organic framework (MIL-101) was synthesized and characterized, which showed a wide surface area (2924.8 m2 g−1 per BET) and a high volume of pores (1.32 cm³ g−1 per DFT). This structure was used to study the adsorption capacity of CO2 and CH4 within systems pressurized up to 100 bar - where a high adsorption capacity of CO2 was evidenced under 45 °C. Moreover, it was possible to distinguish between the high selectivity of this structure for CO2 molecules and its low capture of CH4 molecules. Also, the high stability of MIL-101 was noted after 6 cycles of adsorption and desorption of CO2 under 50 bar and 45 °C, thereby maintaining its adsorption capacity and crystallinity. Finally, isotherms of CO2 adsorption were successfully adjusted with the use of the Toth model.

Experimental investigation supported by artificial neural networks (ANNs) for predicting the heating performance of a cyclone separator coupled with induction heating coil

This paper proposes a novel dust separation and thermal inactivation system that couples an electromagnetic induction heating coil with a cyclone separator. The idea is aimed at the thermal inactivation of potential microorganisms (viruses and other pathogens) associated with dust-laden gas streams, particularly from road surfaces. The integrated system was tested in an experimental setup as a proof-of-concept investigation at different cyclone-induction heating temperatures of 100–400 °C (373–673 K) and air discharge flow velocities of 5–30 m/s. In addition, the influence of operating parameters such as cyclone heating temperature (as induction heating inputs), inlet air velocity, and heating time on the efficacy of the induction heating process were investigated. The time-averaged temperature measurements along the axial direction (z-down) showed predominant temperature fluctuations in the cylinder and cone sections for all cases, especially when the gas plummets down the cyclone. Temperature was highest in the conical section (z = 525 mm) at 320 °C (593 K) at 5 m/s and lowest in the outlet section (z = 375 mm) at 185 °C, which was expected. The results show that inlet air velocity plays a crucial role in affecting temperature dynamics. Conclusive results indicate that with increasing temperature, pressure drop decreases significantly. Along with the experimental results, multiple regression indices using an Artificial Neural Network (ANN) modeling were used to predict the cyclone’s induction heating performance, showing good prediction quality in terms of the mean square errors (MSE and RMSE) and the correlation coefficient R2: 0.99. The study demonstrates the technical viability of integrating induction heating coil to a cyclone separator for wide temperature applications.

The Secondary Flows in a Cyclone Separator: A Review

A cyclone separator holds significant importance as the primary gas–solid separation apparatus in the industrial sector. Cyclone separators operate based on a fundamental principle, primarily harnessing the centrifugal force produced by the rotation of air in order to segregate solid particles from the gas stream and then collect them. In addition to the main vortex in the flow field, there are a number of secondary flows, which significantly impact the aggregation of fine particles and contribute to the heightened energy consumption. This paper provides a summary of the three secondary flows in a cyclone separator. These include the recirculation flow in the annular space, which is greatly influenced by the inlet particle concentration. Additionally, the short-circuit flow occurs beneath the vortex finder as a result of the collision between the incoming flow and the rotating flow. Furthermore, the eccentric circumfluence is defined as the deviation of the rotation center caused by the interaction between the upward and downward flows near the discharge. This paper aims to establish a theoretical framework to investigate the flow pattern tracking and the mitigation of secondary flows in order to enhance the operational efficiency of cyclone separators.

Innovative membrane with selective gas permeability for alkaline water electrolysis: Dependable cell performance under industrial conditions

Alkaline water electrolyzers use porous diaphragms to separate the gases produced in the two compartments of the cell while enabling ionic conductivity between them. The porosity level of the membrane poses a trade-off between its capability to prevent gas crossover and its ability to facilitate ionic conductivity. The high porosity of the membrane enhances ionic conductivity, but it also increases the rate of undesirable gas crossover. This study introduces a unique diaphragm that exhibits gas permeation anisotropy or "selectivity," which inhibits gas permeation to a greater extent in one direction than the other. Interestingly, the membrane maintains high ionic conductivity, comparable to that of the commercial Zirfon Perl UTP500 membrane. The gas permeation anisotropy arises from the structural design of the membrane, in which one side is smoother and denser than the other. Gas purity measurements for the produced gas streams are conducted under different operation loads, confirming the gas permeation anisotropy of the membrane. The purity of the produced target gas can be improved simply by positioning the membrane in a certain orientation between the two electrodes. Additionally, the membrane demonstrated exceptional durability under industrial operating conditions, maintaining a consistently high level of performance for more than 900 h.

NETmix technology as ozone gas injection system: Assessment of the gas-liquid mass transfer

This work proposes an innovative high-intensity mixer based on the NETmix technology to promote the contact between ozone (O3) gas and water. The NETmix consists of a network of unit cells comprising mixing cylindrical chambers interconnected by prismatic channels. Its exclusive geometry generates successive contacting and splitting of flows, boosting mass transfer rates and rapidly developing an O3-enriched liquid stream. The gas-liquid mass transfer performance of NETmix was evaluated by measuring the volumetric mass transfer coefficient (kLa), standard oxygen transfer rate, standard oxygen transfer efficiency, and energy expenditure parameters. A co-current continuous flow condition was used to introduce a gas stream (consisting of either O3/oxygen(O2) or synthetic air) and a liquid stream (water), whereby it was varied the direction of co-current fluid flow (downwards or upwards) and the injected gas (QG) and liquid (QL) flowrates. The downward flow of gas and liquid streams enhanced the mass transfer phenomenon by at least 43 %. Moreover, the kLa values increased with QL and QG, reaching 2.46 s−1 at a low specific power consumption (25 kW m−3). The NETmix showed kLa values at least one order of magnitude larger than conventional contactors, maintaining a high-energy utilization efficiency (up to 19.4 kgO3 kWh−1).

Regeneration of PbO-deactivated Mn-Ce/Ti-bearing blast furnace slag SCR catalyst: Washing and Mn-Ce reloading

The NH3-SCR of NOx from sintering flue gas can be hindered by PbO, deactivating catalysts and making its regeneration a significant challenge. To address this issue, a novel MnOx-CeO2/Ti-bearing blast furnace slag catalyst was developed and its Pb poisoning mechanism was previously elucidated. In this work, regeneration of Pb-poisoned catalyst was systematically evaluated, including washing with different agents and replenishing MnOx-CeO2 components. The optimal conditions for catalyst cleaning were 1.5 mol/L H2SO4 pickling at 30 °C for 2 h. The doped SO42− could interact with catalyst ingredients, generating sulfate substances that partly transformed into various active sulfur-bearing species. These species enriched the catalyst surface and led to the formation of new S-OH/S = O chemical bonds. Loading MnOx-CeO2 further improved the catalyst's redox capacity by facilitating electronic conversions and increasing chemisorbed oxygen Oα content. The regeneration process also enhanced catalyst surface acidity by generating new N = O and N-OH bonds (N = Mn, Ce), intensifying the adsorption and activation of gaseous NH3. The present work offers new insights into the regeneration of MnOx-CeO2/Ti-bearing blast furnace slag catalyst, particularly for their application in flue gas streams with high Pb content.

Axisymmetric inertialess model for the capture of airborne microparticles using an electrospray

We theoretically analyze the effectiveness of an electrospray of ultrafine droplets to filter out micron sized particles from a gas stream. To that end, we introduce an axisymmetric configuration where the airborne particles merge with the electrospray. The droplets attach to the particles, charging them, and both droplets and charged particles are eventually driven towards a collector by means of an electric field. The attachment process is described through a set of reaction constants based on calculated collision cross-sections, yielding particles with different charge levels. The problem involves computation of the concentrations of each type of particle, the gas flow, and the electric field due to the applied voltages and the space charge. Preliminary numerical simulations show a filtration efficiency that is above 95% for particles larger than about 2μm and rapidly declines for smaller particles, though this drop of the efficiency can be postponed to smaller particle sizes by decreasing the ratio of particle to electrospray fluxes or the ratio of the inlet velocity of the particle carrying gas to the velocity induced by electric forces inside the device. Pending an exhaustive numerical exploration of the parameter space of the system, these results also show that the gas flow structure, which is strongly affected by the charged particles, is key for high filtration efficiency.

Assessing the informational credibility of conspiracy theories: online discussion about the Nord Stream damage

PurposeTo elaborate the picture of credibility assessment by examining how participants of online discussion evaluate the informational credibility of conspiracy theories.Design/methodology/approachDescriptive quantitative analysis and qualitative content analysis of 2,663 posts submitted to seven Reddit threads discussing a conspiracy operation, that is, the damage of the Nord Stream gas pipelines in September 2022. It was examined how the participants of online discussion assess the credibility of information constitutive of conspiracy theories speculating about (1) suspected actors responsible for the damage, (2) their motives and (3) the ways in which the damage was made. The credibility assessments focussed on diverse sources offering information about the above three factors.FindingsThe participants assessed the credibility of information by drawing on four main criteria: plausibility of arguments, honesty in argumentation, similarity to one's beliefs and provision of evidence. Most assessments were negative and indicated doubt about the informational believability of conspiracy theories about the damage. Of the information sources referred to in the discussion, the posts submitted by fellow participants, television programmes and statements provided by governmental organizations were judged most critically, due to implausible argumentation and advocacy of biased views.Research limitations/implicationsAs the study focuses on a sample of posts dealing with conspiracy theories about a particular event, the findings cannot be generalized to concern the informational credibility conspiracy narratives.Originality/valueThe study pioneers by providing an in-depth analysis of the nature of credibility assessments by focussing on information constitutive of conspiracy theories.

Thermodynamic analysis on xenon stripping to shorten restart time in molten salt microreactors

Xenon-135 is the strongest known neutron poison; its precursor chain is prominent in the set of uranium-235 fission products. Compound dynamics in the decay chain result in a large 135Xe concentration spike following shut-down, which can make restarting the reactor difficult or impossible for a period of days. This may be the single greatest hurdle inhibiting nuclear power from breaking into power peaking and remote grid applications. In conventional solid fueled reactors, operators must wait for the super-equilibrium xenon (or 135Xe in concentration above the full-power equilibrium level) to decay before restarting. Molten Salt Reactors (MSRs), which have their fissile nuclides dissolved in a liquid salt, present the opportunity for advective removal of xenon. A stream of helium gas may strip dissolved and entrained xenon such that the core returns to its power dependent equilibrium 135Xe concentration much more quickly than by beta-decay alone. This would allow the reactor to restart sooner. This study investigates the feasibility of restarting a MSR more quickly than traditionally viable. We derived a numerical solver and a single stage equilibrium model of a 2-phase mass transport unit operation to this end. Results show that the thermodynamics of xenon stripping from molten salt fuel are highly favorable, with a very small amount of helium being theoretically required for practical control of the 135Xe decay chain after shut-down. Additionally, fuel lifetime could be extended by exchanging poison reactivity at end-of-life for deeper burn-up; this would require a relatively small operational cost of helium. Further investigation into the kinetics and unit operation design is warranted by the favorable thermodynamic results.

Detection and characterization of mono- and bimetallic nanoparticles produced by electrical discharge plasma generators using laser-induced breakdown spectroscopy

This work investigates the performance of laser induced breakdown spectroscopy (LIBS) for the detection and characterization of nanoparticles generated by spark discharge generators (SDG) and arc discharge generators (ADG). LIBS nanoaerosol analysis was carried out according to both on-line (in a gas stream) and off-line (after collection on a filter) methodologies for monometallic (Cu and Au) and bimetallic (AgCo, SnCu, AgAu) nanoparticles generated by ADG and SDG. It was shown that LIBS is not only capable of detecting the presence of nanoparticles in real time, but LIBS spectra can also be used to provide qualitative and quantitative compositional information, as well as estimates for the particle number concentration. This analytical capability, combined with the compact and robust character of LIBS instrumentation, can be put to use for the real-time monitoring of industrial gas-phase nanoparticle synthesis or environmental or workplace exposure to nanoparticles.

Detailed numerical investigation of the drop aerobreakup in the bag breakup regime

Aerobreakup of drops is a fundamental two-phase flow problem that is essential to many spray applications. A parametric numerical study was performed by varying the gas stream velocity, focusing on the regime of moderate Weber numbers, in which the drop deforms to a forward bag. When the bag is unstable, it inflates and disintegrates into small droplets. Detailed numerical simulations were conducted using the volume-of-fluid method on an adaptive octree mesh to investigate the aerobreakup dynamics. Grid-refinement studies show that converged three-dimensional simulation results for drop deformation and bag formation are achieved by the refinement level equivalent to 512 cells across the initial drop diameter. To resolve the thin liquid sheet when the bag inflates, the mesh is refined further to 2048 cells across the initial drop diameter. The simulation results for the drop length and radius were validated against previous experiments, and good agreement was achieved. The high-resolution results of drop morphological evolution were used to identify the different phases in the aerobreakup process, and to characterize the distinct flow features and dominant mechanisms in each phase. In the early time, the drop deformation and velocity are independent of the Weber number, and a new internal-flow deformation model, which respects this asymptotic limit, has been developed. The pressure and velocity fields around the drop were shown to better understand the internal flow and interfacial instability that dictate the drop deformation. Finally, the impact of drop deformation on the drop dynamics was discussed.

A computational study of a two-fluid atomizing coaxial jet: Validation against experimental back-lit imaging and radiography and the influence of gas velocity and contact line model

Numerical simulations of liquid atomization in a two-fluid coaxial geometry have been performed using a geometric Volume-of-Fluid method. Experimental measurements have been obtained using visible light back-lit imaging and X-ray radiography. Simulations are validated against experiments, using the same geometry and fluid injection rates of air and water, by showing excellent agreement in quantities such as liquid mass distribution in the spray formation region and the liquid jet length statistics and temporal dynamics. At the nozzle exit, the coflowing liquid and gas streams are separated by a cylindrical splitter plate. The liquid is laminar and modeled using a Poiseuille flow while the gas inflow model and the contact line model are varied. For the gas velocity models, the vorticity thickness is shown to have a strong influence on the downstream liquid distribution; the difficulty of its modeling and routes to overcome them are discussed. For the contact line model, pinning the interface to the inner wall of the splitter plate leads to an initial increase in the diameter of the liquid jet just downstream of the nozzle exit. In contrast, pinning to the outer wall of the splitter plate or allowing for a free moving contact line results in a monotonic decrease in the diameter of the liquid jet as the downstream distance is increased, in agreement with the experimental observations and measurements. A sub-grid scale contact line model based on a static contact angle is introduced. The static contact angle is varied in the model, showing that the liquid remains intact longer as the static contact angle is increased.

How flue gas impurities affect the electrochemical reduction of CO2 to CO and formate

The electrochemical CO2 reduction offers a promising solution to convert waste CO2 into valuable products like CO and formate. However, CO2 capture and purification remains an energy intensive process and therefore the direct usage of industrially available waste CO2 streams containing SO2, NO and O2 impurities becomes more interesting. This work demonstrates an efficient (Faradaic efficiency > 90 %) and stable performance over 20 h with 200 ppm SO2 or NO in the feed gas stream. However, the addition of 1 % O2 to the CO2 feed causes a significant drop in Faradaic efficiency to C-products due to the competitive oxygen reduction reaction. A potential mitigation strategy is to operate at higher total current density to firstly reduce most O2 and achieve sufficient product output from CO2 reduction. These results aid in understanding the impact of flue gas impurities during CO2 electrolysis which is crucial for potentially bypassing the CO2 purification step.

Analysis of CO2 hydrate formation from flue gas mixtures in a bubble column reactor

Gigascale carbon capture and sequestration (CCS) is increasingly seen as essential to meeting the targets of the Paris Agreement. As an alternative to conventional CCS approaches, carbon dioxide (CO2) hydrates have received attention as materials which can enable new approaches to carbon capture as well as carbon sequestration. CO2 hydrates (ice-like materials of CO2 and water) form at medium pressures (<400 psi) and temperatures of >0 °C from a water-CO2 mixture. Bubble column reactors (BCR) have been studied as a preferred way of forming CO2 hydrates. This study uses an inhouse, recently-developed modeling framework to predict performance of a BCR for CO2 hydrate formation from flue gas (CO2/N2), and pure CO2 streams. We highlight and analyze specific aspects of hydrate formation that are important for CO2 sequestration, and for CO2 separation/capture. In particular, two performance parameters are analyzed: i) gas consumption rate for hydrate formation (normalized with reactor volume), and ii) fraction of CO2 that converts to CO2 hydrates in a single pass (conversion factor). The first metric quantifies the overall productivity of a BCR by obtaining the net CO2 that can be sequestered or separated from the flue gas stream. The second metric relates to the efficiency of the system by quantifying the need for recirculation and the quality of the exit stream after a single pass. Extensive parametric analysis is conducted to study the influence of pressure, temperature, CO2 mole fraction at inlet, gas flow rate and reactor geometry on hydrate formation. Across the range of simulations conducted in this study, the highest gas consumption rate per unit reactor volume was 28.9 ton/yr/m3 and the highest conversion factor was 67.8 %. Both parameters increase with increasing pressure, decreasing temperature and increasing inlet mole fraction of CO2. Increasing gas flow rate increases the gas consumption rate (i.e., hydrate formation rate) but reduces the conversion factor. This suggests that the overall productivity of BCRs increases with gas flow rate at the expense of its efficiency. Reduced efficiency increases recirculation-related costs and high flow rate increases compression and cooling costs. For flue gas, increasing the reactor volume by increasing the height or diameter increases conversion factor but significantly reduces the gas consumption rate per unit reactor volume. For pure CO2, increasing the reactor height increases the conversion factor without changing the volumetric gas consumption rate. Decreasing the diameter increases volumetric gas consumption rate without changing the conversion factor. These findings suggest that compact reactors are more suitable for CO2 hydrate slurry production (on a volumetric basis), while larger reactors are suitable for CO2 separation/capture applications. Overall, this study provides a basis for the design and operation of BCRs for CO2 hydrates-based CCS applications.

Application of Schlieren photography for visualisation of a pulsed gaseous target

The article describes Schlieren photography, realised using a laser plasma as a radiationsource. Optical systems prepared for visualisation of a stationary gas outflow and a pulsed gaseoustarget, produced in an atmosphere or vacuum environment are presented. A He-Ne laser beam orlaser plasmas were used as the light sources. Schlieren images of outflows of helium, carbon dioxide,krypton, nitrogen and sulphur hexafluoride, are presented. A comparison of various gas streams,formed in atmosphere, imaged using different light sources are shown. Schlieren images of a twostreamgaseous target formed in vacuum are also presented.Keywords: automation, electronics, electrical engineering and space technology, refraction, opticalsystem, laser plasma, schlieren photography

A cyclic sorption-reaction process for continuous synthetic methane production from flue gas and green hydrogen

In the scope of Power-to-Methane processes, green H2 and CO2 (captured from flue gas, for instance) can be catalytically converted to CH4 (or synthetic natural gas), an easily stored and distributed energy vector. From the perspective of process intensification, the CO2 capture (by sorption) and conversion can be performed in the same multifunctional reactor, thus requiring fewer operational units and potentiating the synergy between the exothermic methanation and the endothermic CO2 desorption. In this regard, two reactors were individually packed with alternating layers of two commercial materials, a CO2 sorbent (K-promoted hydrotalcite) and a methanation catalyst (Ru-based), and tested to carry out a cyclic sorption/reaction process. The feed during the sorption stages consists of a synthetic flue gas stream containing 15 %vol. of CO2 balanced in N2. In the reactive regeneration stage, the inlet is pure H2, which reacts with the previously sorbed CO2, producing CH4. The two sorptive reactors were operated in parallel and out of phase until a cyclic steady-state was reached. The employed materials showed no signs of deactivation during over 150 h of time on stream. The performance of the cyclic unit was tested under different operating conditions, in a parametric study that assessed the influence of each variable on several performance indicators like CH4 productivity and CH4 purity. The study was carried out at atmospheric pressure and centered on a reference experiment in which a CH4 productivity of 1.12 molCH4·kgcat–1·h−1 and a purity of 60.8 % were obtained, using 200 mLN·min−1 of synthetic flue gas (15 %vol. CO2) and 100 mLN·min−1 of H2, at 350 °C and a switching time of 30 min. Nevertheless, all performance indicators could be improved in other operating conditions (CH4 purity up to 71.6 % and CH4 productivity up to 1.32 molCH4·kgcat–1·h−1).

Real Fluid Modeling and Simulation of the Structures and Dynamics of Condensation in CO2 Flows Shocked Inside a de Laval Nozzle, Considering the Effects of Impurities

Because of the currently changing climate, Carbon Capture and Storage (CCS) is increasingly becoming an important contemporary topic. However, this technique still faces various challenges. For the compression of CO2 to its supercritical condition for efficient transport, one of the important challenges is mastering the two-phase flow in the pump. Indeed, phase changes that appear on the blade tips of an impeller or rotor in such pumps can lead to performance and stability issues. Moreover, these phase change phenomena (vaporization and condensation) can be significantly modified by the presence of impurities (N2, O2, H2S, etc.) whose nature depends on the source of the CO2 production. In this work, we focus on analyzing the high pressure flow behavior of CO2 mixed with varying levels of impurities in a de Laval nozzle, for which experimental results are available. Numerical simulations are performed using a real-fluid model (RFM) implemented in the CONVERGE CFD solver. In this model, a tabulation approach is used to provide the thermodynamic and transport properties of the mixture of CO2 with the impurities. The study is carried out with different inlet conditions, and the results are in good agreement with the available experimental data. In addition, the results provide insights on the interaction of the shock wave with the observed condensation phenomenon, as well as its impact on the amount of condensation and other thermodynamic variables. The research indicates that the presence of impurities mixed with CO2 significantly affects the observed condensation in gas streams, which is a crucial factor that cannot be overlooked when implementing CCS systems.