Condensation Process Research Articles

Bio-polymer based thermally stable composites as catalytic support materials for energy harvesting process

In the present work, bio-based conductive polymer composites were developed to utilize as supporting material for anode catalysts for oxidation of fuels to generate electrical energy. An in-situ method was adopted to synthesize the conducting polymer carbon composites through combined condensation process by reacting terephthalaldehyde and benzidine, and reinforced with almond shell carbon (BT-ASC). Using formaldehyde reduction method platinum-tin nanoparticles were deposited on BT-ASC composites and were characterized using modern analytical instruments., viz., X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDAX) and Fourier transform infrared spectroscopy (FT-IR). Thermal stability of the conducting polymer composites was analyzed by thermogravimetric analysis (TGA). The electrochemical properties of the prepared catalysts were studied by cyclic voltammetry and chronoamperometric analyses. Data obtained from different studies inferred that the Pt–Sn/BT-ASC catalyst possesses the maximum current density (88.6 mA/mg) with minimum oxidation potential than those of Pt–Sn/ASC, Pt/BT-ASC and Pt/ASC catalysts. The present work ascertains the importance of conducting polymer composites developed using reinforced with bio-carbon towards electro-oxidation of methanol and these supporting materials possess an enhanced catalytic activity than that of reported catalysts.

Exploring the effect of surface wettability on heterogeneous condensation of carbon Dioxide: A molecular dynamics study

The condensation characteristics of carbon dioxide (CO2) are critical for several engineering applications, including pressurized liquefied natural gas technology and carbon capture, utilization, and storage (CCUS). This study applies molecular dynamics simulations to investigate CO2 condensation on different solid surfaces by modulating the solid–liquid interaction coefficient, α, to alter wettability. The CO2 condensation process is categorized into three phases: nucleation, coalescence, and growth. Our findings suggest that increasing the α value not only enhances surface wettability but also alters the condensation of CO2 from a droplet to a film form. Higher α values are linked with increased condensation rate and liquefaction degree, thus leading to improved heat transfer performance. The effects of different initial system pressure (p0) and cooling temperatures (Tcold) on CO2 condensation are also examined. A reduction in Tcold and an increase in p0 both contribute to an enhanced liquefaction rate and degree of CO2 and improve heat transfer. For instance, when α = 0.10, decreasing Tcold from 200 K to 180 K increases the CO2 liquefaction rate from 46.68% to 72.95%, and when α = 0.24, the rate grows from 80.81% to 91.99%. This study provides pioneering insights into the heterogeneous condensation and heat transfer processes of CO2 at the microscopic level, potentially offering valuable knowledge for optimizing CO2 capture or removal in engineering applications.

Experimental study on the dew point corrosion behavior in atmospheric tower system

Atmospheric towers are large pieces of equipment used in the petroleum refining process. Hydrochloric acid dew point corrosion often occurs at low-temperatures in the tower. In order to study the dew point corrosion problem of atmospheric tower in a petrochemical enterprise, the process simulation method was used to determine the logistics parameters in the high risk area of dew point corrosion of atmospheric tower system. Based on this, the experimental conditions were set up to closely integrate laboratory research with engineering practice. In view of this special and complex corrosion process, a dew point corrosion experiment was designed to realize the dew point condensation process. The influence of concentration and temperature on the dew point corrosion rate was explored by an electrochemical test and a corrosion weight loss method. The results show that the initial dew point temperature of the tower is 89 ℃, and the risk area of dew point corrosion is located at the top of the tower and in the position of the volatile line, which is consistent with the actual corrosion area of the equipment. In this logistics environment, the dew point corrosion rate of Q345R steel increases with the increase in HCl concentration and temperature in the atmospheric tower system.

Pyrolysis of an organic-rich shale containing type II kerogen before and after oil generation and expulsion: Implications for the generation of late hydrocarbon and hydrogen gases

Thermal simulation of late gas generation of source rock is critical for evaluating the potential of deep gas and shale gas. Retained oil and its interactions with thermally mature kerogen can have a significant impact on late gas generation from source rocks; however, previous studies commonly used expelled oil or total oil, which have different compositions from retained oil. In addition, molecular hydrogen (H2 gas) is not only a pyrolysis product but may also have significant effects on hydrocarbon formation. The effects of oil generation and expulsion, as well as retained oil, on H2 generation from source rocks are currently poorly understood. Our study involved two-stage pyrolysis under high-pressure conditions: main oil generation and expulsion, followed by late gas generation. The yields of both hydrocarbon gas and H2 gas were determined and examined deeply in order to investigate the influence of key factors on late gas generation, such as oil generation and expulsion and the interactions between retained oil and mature kerogen. Furthermore, the influence of kerogen type and thermal maturity on late hydrocarbon gas potential was discussed with a literature review. Firstly, oil generation and expulsion could significantly reduce the yields of methane, C2–5 and H2 gases from the pyrolysis of shale. After oil expulsion, the mature shale produced both CH4 and H2, the majority of which came from the kerogen cracking. The interactions between mature kerogen and retained oil may have slightly promoted the generation of methane and inhibited the generation of H2, but they had little influence on the potential for total hydrocarbon gas. Secondly, the H2 generation process could be sub-divided into four stages, which correspond to early hydrocarbon gas generation (stage I), main C2–5 gas generation (stage II), main C2–5 gas cracking (stage III) and the latest methane generation (stage IV), respectively. More than 80% of the total H2 yields were produced in stages III and IV, suggesting that most of the H2 gas was generated through the demethylation, aromatization and condensation processes. Finally, this study concluded that the late hydrocarbon gas potential of different types of kerogen is mostly related to thermal maturity and can be represented by a simple power function.

Thermodynamic characteristics of the hot-temperature cavity generated by the spark discharge in saline water

Spark discharge in saline water can generate cavity oscillating violently. However, the thermodynamic characteristics of such a cavity is still unclear owing to the complex mechanism behind it. In this study, a systematic model is developed with the considerations of thermal radiation and mass transport, which can successfully evaluate the thermodynamic properties of the spark-induced cavity in saline water. The physical parameters related to the mass transport are identified by comparing with the experimental measurements. By using the validated parameters, we find that the thermal radiation and the condensation process cannot be ignored, and the number of water molecule increases at the first collapse point. In addition, the maximum cavity size increases with increasing absorption of thermal radiation, but decreases when the condensation coefficient increases. Increasing the discharge energy and ambient temperature are found to help generate larger cavity. The inner temperature and pressure at the collapse phase increases with the increase of the discharge energy, whereas decreases when the ambient temperature increases. Furthermore, the minimum temperature at the first maximum size is up to 3000 K under 0.1 MPa, and reaches 8000 K when the ambient pressure is larger than 1 MPa. Thus, we believe the spark-induced cavity in saline water is hot, at least during the first oscillation cycle.

Pt clusters in carbon network to enhance photocatalytic CO2 and benzene conversion of WOx/g-C3N4 nanosheets

Noble metals in carbon networks dramatically improve the carrier separation and transfer efficiencies of layered graphic carbon nitride (g-C3N4) based heterostructures for efficient CO2 and benzene photocatalytic conversion. Here, Pt clusters are homogeneously incorporated into ultrathin g-C3N4 nanosheets via multi-step treatment method using the combinations of mechano-chemical pre-reaction and two-step thermal condensation processes. Small Pt nanoparticles with diameters of less than 5 nm are observed and WOx nanobelts with increased oxygen vacancies (as the active sites) are horizontally grown on the thin Pt-g-C3N4 nanosheets. The photocatalytic activities of the constructed composite materials are evaluated under full solar spectrum irradiation condition including water splitting, CO2 photoreduction, and benzene to phenol conversion. The WOx/Pt-g-C3N4 nanosheet heterostructures with optimized preparation condition and without adding any co-catalyst reveals enhanced H2 generation (5267 μmolg−1h−1) and CO2 photoreduction (5.89 and 3.12 μmolg−1h−1 for CO and CH4 conversion rate, respectively), as well as improved benzene to phenol conversion (89.0%) and selectivity (98.2%). The presence of Pt clusters in the heterostructures improves charge transport in-between g-C3N4 and WOx, thus enhances the charge separation efficiency of the composite material. Detailed photocatalytic mechanisms are discussed on the alteration from S-scheme WOx/g-C3N4 heterostructure to Z-scheme WOx/Pt-g-C3N4 heterostructure.

Facile Synthesis, Spectroscopic and Nonlinear Optical Insights of Hydrazinyl-Based Functional Materials: Experimental and DFT Approach

A series of hydrazinyl thiazol-4-one based scaffolds (EBHT1-ETHT5) had been prepared through condensation process of substituted thiosemicarbazone with ethyl bromoacetate and sodium acetate. The structure confirmation of formed compounds was done through several spectroscopic methods. Beside synthesis, quantum chemical investigations were executed at MPW1PW91/6-311G(d,p) functional to explore nonlinearity of EBHT1-ETHT5. At first, the structures of prepared chromophores were optimized to get true minima geometries. These optimized geometries were further utilized to carry out the natural bond orbitals (NBO), transition density matrix (TDMx), UV-Vis analysis, density of states (DOS), and nonlinear optic (NLO) characteristics. A minimum Egap (4.433 eV) was achieved in EBHT1 with wider absorption spectrum (λ max= 339 nm) than that of other yielded compounds. A significant charge transference is seen with in molecules through DOS and TDM findings. The GRPs findings explored that all the afore-said chromophores had higher value of global hardness (η = 4.433–4.657 eV) along with lower softness (σ = 0.432–0.277 eV). Significant NLO results were obtained for prepared chromophores as compared to reference urea chromophore. These organic chromophores can be considered as potential candidates in NLO-based applications.

Selective adsorption of carbonyl compounds from bio-oil by seaweed-derived carbon: A theoretical study

Bio-oil is a renewable fuel widely used in the chemical industry, but its high oxygen content results in thermal instability and a low heating value. In order to address this issue, the current study aims to use seaweed-derived biochar as a substrate to selectively adsorb carbonyl compounds from the volatile matter during the bio-oil condensation process. The interaction between acetone and different nitrogen-rich seaweed-derived carbon models were analysed using acetone as a model compound and density functional theory. The adsorption structure, energy, and surface electronic properties between acetone and each seaweed-derived carbon model were analysed. Since nitrogen electronegativity is higher than carbon’s, electron-rich nitrogen, and electron-deficient carbon are formed, thereby increasing the adsorption capacity of nitrogen-doped carbon. The results of this study will provide insight into the adsorption mechanism of seaweed biochar and offer a new approach to reducing the oxygen content of bio-oil and improving its quality.

Numerical analysis of transient heat and mass transfer for a water heat pipe under non-uniform heating conditions

Non-uniform loads are widely present in heat pipe applications and have significant effects on their performance. In this work, a transient 3D CFD model is developed to investigate the liquid–vapor flow and heat transfer for a water heat pipe under various non-uniform loads. The source terms are added to the governing equations using the User-Defined Function (UDF) to simulate the evaporation and condensation process. The model is verified using the experimental and simulated data under uniform and non-uniform loads in the literature. The effects of key parameters including adiabatic length, heating power, and heat distribution on the thermal performance of heat pipes are analyzed. The results show that the non-uniform conditions would shift the maximum axial velocity of vapor to the unheated side and induce a significant circumferential flow in the wick region, especially in the evaporator section. The short adiabatic length and high heating power could reduce the elapsed time of reaching the steady state. The heat distribution in the evaporator section exhibits little effect on the elapsed time reaching the steady-state and the average steady-state vapor temperature

Research on non-equilibrium condensation of supercritical carbon dioxide in sCO2 power systems

Based on the consideration of sustainable development and energy efficient transformation, people propose using renewable energy to upgrade traditional power generation systems. The supercritical carbon dioxide (sCO2) Brayton cycle has a great utilization potentiality in thermodynamic systems, such as solar thermal power generation systems. When the CO2 fluid flows into the compressors of sCO2 power systems, there is a risk of non-equilibrium condensation due to local expansion and acceleration, which seriously threatens the stability of the whole system. The convergent-divergent nozzle is usually used to study non-equilibrium condensation. In this paper, the wet steam model is used to simulate the non-equilibrium condensation of the CO2 fluid near its critical region in a convergent-divergent nozzle. The phase change model and the thermophysical equation of state are verified by experimental data. The non-equilibrium condensation process is analyzed, and the droplet nucleation process and droplet growth process are described. Non-equilibrium condensation releases the latent heat and forms a condensation shock wave. The influences of the shock wave effect on temperature, pressure, and other parameters are discussed. The initial condensation position and critical subcooled temperature under different inlet conditions are analyzed.

A new biomass-based hybrid energy system integrated with a flue gas condensation process and energy storage option: An effort to mitigate environmental hazards

The development of biomass-fueled cogeneration plants can be fruitful to achieve the sustainable development goals, due to the crises of fossil energy-fueled ones. Additionally, biomass fuels can offer higher reliability and more sustainable energy compared to the two more well-known renewables (i.e., solar and wind energies) due to the no dependence on environmental and weather conditions. The present article provides a comprehensive assessment (thermodynamic-design, exergoeconomic and environmental) and optimization of a new biomass-driven cogeneration plant cascaded with a heat recovery unit. The planned plant is based on a biomass gasification process, some thermodynamic power generation cycles based on steam and gas turbines (i.e., Rankine cycle, Brayton cycle, and organic Rankine cycle (ORC)), and flue gas condensation process. Besides, a compressed air energy storage system (CAESS) as an energy storage process is integrated with the considered plant to establish a balance between production and demand and reduce electricity costs. To achieve optimal performance, a multi-objective optimization (based on a genetic algorithm) is applied. The findings showed that by considering the multi-objective optimization techniques, the plant's exergy efficiency could improve by about 15%. At the same time, the exergy cost rate is reduced by almost 17.3%. Avoiding the payment of carbon tax and the high electricity production level in the on-peak consumption period are unique and competitive features of the proposed biomass-driven power plant. It was also found that the LCOE and the payback period were 13.27 USD/GJ and 2.03 years, respectively, therefore, the proposed power plant exhibits reasonable economic feasibility.

The optimal design of solid oxide and molten carbonate fuel cells integration with a CO2 recycling unit: An attempt to reach a clean transition process

High-temperature Solid Oxide Fuel Cell (SOFC) technology has great potential as a clean and effective energy source. However, several issues have prevented their widespread adoption, like high operating costs, difficulty integrating with other components, and being sensitive to fuel contamination. In order to address these challenges, the main novelties of the present work are carbon capture and utilization for clean energy production, using the flue gas condensation process as a cost-effective and energy-efficient strategy, and the combination of Molten Carbonate Fuel Cells (MCFC) for increased energy efficiency and most effective component integration. The proposed novel system is also equipped with a gasifier and vanadium chloride unit for syngas and clean hydrogen production. The system's practicality is evaluated by analyzing the key performance indicators from thermodynamic, exergo-economic, exergo-environmental, and sustainability viewpoints. Also, the Sankey diagram is presented to investigate each component's effectiveness from the exergy destruction facet. According to the findings, at the most optimum design condition, the acceptable energy and exergy efficiencies of 61.06% and 50.66%, respectively, are achieved, revealing the system's effectiveness. The suggested system is also financially attractive since it achieves a reasonable levelized power cost of 17.6 $/MWh at a total cost of 44.1 $/h. The findings show that carbon dioxide recovery is crucial in reducing the pollutants due to the low emission index of 5.01 kg/GWh. Finally, the exergo-environmental index, environmental damage effectiveness, and exergy stability factor have equivalent values of 0.012, 0.59, and 0.54.

Numerical investigation of the gravity effect on two-phase flow and heat transfer of neon condensation inside horizontal tubes

The condensation flow and heat transfer characteristics of cryogenic neon inside horizontal tubes with diameters of 1 mm and 2 mm were numerically investigated. The mass flux ranged from 20 to 187 kg/(m2·s) for gravity levels includes zero gravity, Lunar gravity, Martian gravity, and Earth gravity. The effects of gravity on the condensation flow pattern, local condensate film distribution, and local and global heat transfer were analyzed in detail. The gravity effect on the condensation heat transfer showed three states, including enhancement, deterioration and gravity-independence, which were mainly determined by the mass flux and vapor quality. Under normal gravity, the condensation heat transfer coefficients increased with increasing mass flux and decreasing tube diameter. Under low mass flux, the cryogenic neon underwent enhanced condensation heat transfer under zero gravity and reduced gravity in the high vapor quality region but deteriorated condensation heat transfer in the low vapor quality region. By increasing the mass flux, the gravity effect was effectively suppressed, which resulted in gravity-independent behavior of condensation heat transfer in the high vapor quality region. The gravity effect significantly affected the liquid film distribution in the condensation process, with a more uniform distribution of the liquid film appearing along the circumferential direction as the gravity level decreased. However, due to the low surface tension of the deep cryogenic fluid, the condensation interface was more prone to flow instability under reduced gravity levels.

Testing of Desalination Equipment with Condensation Process as a Solution for Islands That Lack Fresh Water

The purpose of this study was to find out: (1) the volume of fresh water produced from the desalination process; (2) the acidity of water produced from seawater desalination equipment using solar energy. Seawater desalination device model uses solar power. The model of the tool is made in the form of a box (Square). At the bottom there is a seawater reservoir and on the bottom side of the desalination equipment there is a desalination freshwater path connected to the freshwater storage container. In the data collection process, the tool is placed in an open area that can be exposed to direct sunlight, data collection starts from seawater sampling, seawater sampling and testing. The seawater that has been taken is then lifted to the research site and put into the seawater storage area. The conclusions that can be drawn from this study are: (1) from the tool that has been tested obtained a tool that can produce fresh water, the first test 18 ml, the second test 14 ml and the third test 23 ml and the acidity of the water is 7% pH or no acidity of water and also this tool can be applied in the tropics; (2) Seawater desalination equipment into fresh water with solar energy that has been made with a box model using glass, at the base of the desalination tool there is a seawater storage pool and on the bottom side of the desalination tool there is a freshwater path.

The Characterizations of Professor Snape in J. K. Rowling’s Harry Potter And The Philosopher’s Stone

J. K. Rowling’s Harry Potter and the Philosopher's Stone has presented readers with different unique teachers. Even though Rowling’s series disclose Professor Snape as a hero, the first novel depicted him as an insufferable character set to thwart the main characters’ adventure. This study aimed to provide more objective portrayals of Professor Snape through interactive qualitative data analysis. The subject of the study is J. K. Rowling’s Harry Potter and the Philosopher’s Stone. Meanwhile, the characterizations of Professor Snape become the object of the study. As the main instrument of data collection, the researcher conducted close reading. The analysis consisted of a concurrent process of data condensation, data display, and conclusion drawing, which are also synchronized with the data collected at the beginning of the research. This study reveals that Professor Snape was depicted as knowledgeable, curious, observant, hardworking, loner, partial, loyal, responsible, and authoritative. These results show that Professor Snape has good characters. However, they were overshadowed by his brooding appearance. This conclusion implies that students should not judge their teacher or others based on their appearance.

Hetero-dimeric covalent-organic pillars with aliphatic linkers

Penta-bridged covalent bis-pillar[5]arenes have garnered significant attention recently as single-molecule nanotubular structures. In this study, we synthesized hetero-dimeric covalent-organic pillars (hetero-COPs) by coupling penta-aldehyde and penta-amine pillar[5]arene derivatives. NMR spectroscopic, mass spectrometric, and X-ray crystallographic analyses confirmed the formation of a pair of directionally asymmetrical hetero-COPs with an overall length of 1.8 nm. Furthermore, we observed social chiral sorting during the [1 + 1] imine condensation process of these macrocyclic building blocks. Although the synthetic efficiency requires further improvement, our findings provide valuable insights into the design of directional nanotubes based on bis-pillar[5]arene.

Modeling of monolayer water adsorption on surface of cement minerals by molecule simulation and adsorption isotherm

The performance of water on the pore surface governs the mechanical properties and durability of cementitious materials and structures. As a fundamental mechanism, the interaction between water and cementitious mineral micropore surfaces behaves differently under various circumstances, which can be investigated by molecular simulation methods in detail. Molecular simulations based on Grand Canonical Monte Carlo method were performed to obtain the water vapor adsorption isotherms on the surface of tricalcium silicate (C3S) and calcium hydroxide (CH), which are selected as typical cement mineral and hydration product respectively. The adsorption behavior of C3S and CH is compared by the adsorption energy and adsorption isotherm model. The condensation processes were explained by the Kelvin equation. The critical pore sizes of C3S and CH for condensation are 19 Å and 15 Å respectively. Beyond the critical pore size, water adsorption shows monolayer adsorption performance. The water adsorption process on the surface includes three stages: rapid adsorption, stable adsorption and slightly condensed adsorption, which are related to the surface interaction of minerals with water molecules. The Langmuir model is more suitable for the CH with homogeneous surface, while the Freundlich model is more suitable for the C3S model with nonhomogeneous surface. The adsorption heat of the first layer of water film and adsorption energy on the surface of CH are higher.

Research on a two-phase condensation model with predictable turbulent film

Steam condensation containing non-condensable gases is the main method of heat removal under severe nuclear accidents. To investigate the condensation characteristic, several numerical simulation studies have been conducted. Previous numerical models generally assume that the condensate film is thin or even negligible owing to the existence of non-condensable gases. However, the condensation rate improved rapidly as steam concentration rises. As the condensation rate rises, the velocity and thickness of the film will also sharply increase, thereby affecting the condensation process. In this case, the film flow will transition to a turbulent regime. To consummate the condensation model, a two-phase condensation model with predictable turbulent film was proposed. The model can predict the condensation performance well in a broad range, with deviation generally within 20%. In addition, the prediction correlation and contour diagram were obtained to identify the thermal resistance ratio and the flow regime of the film according to the proposed model.

Analysis of Cloud Growth Phases When Nocturnal Hail Occurs (Case Study: Sekadau, 22 August 2020)

On August 22 2020, hail was reported in Sekadau, West Kalimantan at 21:23 WIB. The phenomenon of hail does not usually occur at night. So, further research is needed to find out how the cloud growth phase and Cumulonimbus (Cb) cloud structure are in this phenomenon. This research utilizes remote sensing instruments in the form of a C-Band type weather radar for the Supadio Meteorological Station and the Himawari 8 Satellite, as well as a radiosonde instrument that is closest to the time and location of the hail events. The results of satellite imagery show that nocturnal hail occurs before the clouds reach the mature phase, with the cloud top temperature at the time of hail less than -60 ºC. The maximum reflectivity detected by the radar using CMAX products shows a less significant value with an intensity of up to 52 dBZ. The VCUT product shows the maximum intensity altitude is at an altitude of 5 – 8 km. This shows that there is a process of ice condensation on the freezing level layer. The ZHAIL product image shows that there is a potential for hail in the Sekadau area with a probability of more than 80%. The occurrence of ice rain at Sekadau at night is caused by the presence of Cumulonimbus clouds with very cold peak temperatures and the mixing process above the freezing level which supports the formation of ice condensation in Cb clouds.

Identification and Characterization of DNA-Oxaliplatin Adducts through α-hemolysin Nanopores.

The antitumor effect of Pt-based drugs is determined by their binding activity with deoxyribonucleic acid (DNA), and understanding the reaction process in a systematic manner is crucial. However, existing assays used for DNA-Pt research suffer from several issues, such as complicated sample preparation, preamplification, and expensive instruments, which dramatically limit their practical application. In this study, a novel method was presented to investigate the adducts of DNA and oxaliplatin using an α-hemolysin nanopore sensor. This approach allows for real-time monitoring of the DNA-oxaliplatin condensation process through the detection of nanopore events associated with DNA-oxaliplatin adducts. Specifically, type I and II signals exhibiting specific current characteristics were observed during the process. Typical signals with high frequency were obtained by recording the designed DNA sequence. Furthermore, the production of these signals was confirmed to be independent of homologous adducts. This finding suggests that the DNA-oxaliplatin adduct can serve as a potential sensor for detecting oxaliplatin lesions and multiple types of molecules.