Gaseous Water Research Articles

Utilization of synthesized silane-based silica Janus nanoparticles to improve foam stability applicable in oil production: static study

This study investigated the effect of silane-based silica (SiO2) Janus nanoparticles (JNPs) on stabilizing the foam generated by different types of gases. Two types of SiO2 JNPs were synthesized through surface modification using HMDS and APTS silane compounds. Static analyses were conducted to examine the impact of different concentrations of the synthesized nanoparticles in various atmospheres (air, CO2, and CH4) on surface tension, foamability, and foam stability. The results indicated that the synthesized SiO2 JNPs and bare SiO2 nanoparticles exhibited nearly the same ability to reduce surface tension at ambient temperature and pressure. Both of these nanoparticles reduced the surface tension from 71 to 58–59 mN m−1 at 15,000 ppm and 25 °C. While bare SiO2 nanoparticles exhibited no foamability, the synthesis of SiO2 JNPs significantly enhanced their ability to generate and stabilize gas foam. The foamability of HMDS-SiO2 JNPs started at a higher concentration than APTS-SiO2 JNPs (6000 ppm compared to 4000 ppm, respectively). The type of gas atmosphere played a crucial role in the efficiency of the synthesized JNPs. In a CH4 medium, the foamability of synthesized JNPs was superior to that in air and CO2. At a concentration of 1500 ppm in a CH4 medium, HMDS-SiO2 and APTS-SiO2 JNPs could stabilize the generated foam for 36 and 12 min, respectively. Due to the very low dissolution of CO2 gas in water at ambient pressure, the potential of synthesized JNPs decreased in this medium. Finally, it was found that HMDS-SiO2 JNPs exhibited better foamability and foam stability in all gas mediums compared to APTS-SiO2 JNPs for use in oil reservoirs. Also, the optimal performance of these JNPs was observed at a concentration of 15,000 ppm in a methane gas medium.

Green Polymer Poly‐l‐proline Efficiently Inhibits Formation of Gas Hydrates in Oil–Water System

AbstractGreen polymer poly‐l‐proline, as a new type of biodegradable polymer material, has a wide application prospect in the field of environmental protection. Recent studies have shown that poly‐l‐proline can also act as a green inhibitor that is highly effective in inhibiting the production of gas hydrates in oil–water systems. As a natural polymer material, poly‐l‐proline has good biocompatibility and biodegradability and will not cause pollution to the environment. It is found that adding an appropriate amount of poly‐l‐proline to the oil–water system can significantly inhibit the formation of gas hydrates. This is because poly‐l‐proline can reduce the concentration of dissolved gases in water by adsorbing and dispersing ions and molecules in water, thereby reducing the chance of gas forming hydrates with water. In addition, poly‐l‐proline can also prevent gas molecules from entering water molecules to form hydrates by forming hydrogen bonds with water molecules. This study provides a green, environmentally friendly and efficient solution for controlling the formation of gas hydrates in oil–water mixtures. In the future, the application prospects of poly‐l‐proline in oil–water separation, marine engineering, natural gas exploitation, and other fields will be broader.

Acidificação oceânica: uma questão negligenciada

Oceans play a crucial role in many natural processes, such as oxygen production and climate regulation. Ocean acidification (OA) is a phenomenon caused, among other factors, by the dissolution of certain gases in water, such as carbon dioxide (CO2). It is estimated that by 2100, the partial atmospheric pressure of carbon dioxide (pCO2) will double from pre-industrial levels, aggravating this process. The negative consequences of OA are not yet fully understood, in part due to the limitations of laboratory experiments. However, it is known that they include increased concentrations of CO2 in the atmosphere, structural and functional modifications of ecosystems, changes in richness, diversity and geographic distribution of species, impairment of ecosystem goods and services, and commercial activities, such as fishing and aquaculture, as well as global warming. OA, in principle, is considered irreversible, as it depends on the reduction of emissions of the gases involved in the process, especially CO2, and the slow natural process of neutralization. However, some mitigation measures, allied with adaptation measures, can mitigate the effects of OA. These and other issues related to ocean vulnerability caused by climate change will be raised in this review.

Performance analysis of a novel absorption-refrigeration driven membrane condenser system for recovery of water and waste heat from flue gas

Dehumidification of industrial flue gas with a membrane condenser requires cooling energy so that the water in the flue gas will recover as it gets condensed due to the cooling process. In this study, the utilization of the waste heat energy of the flue gas to drive an absorption refrigeration cycle is suggested. In return, the cooling energy of the refrigeration cycle is utilized to cool the flue gas before it is admitted to the membrane condenser. The thermal analysis of the refrigeration cycle is carried out by considering a numerical heat transfer analysis at the desorber. The energy and mass balance of the whole refrigeration cycle is carried out based on thermodynamic governing equations. Furthermore, the water recovery process of the membrane condenser which is integrated with the absorption refrigeration cycle is studied. The numerical modeling of the refrigeration cycle and the membrane condenser are combined to investigate the operating parameters of the system. The influence of inlet temperature and mass flow rate of the feed flue gas on the performance of both the refrigeration cycle and membrane condenser is studied.

Influence of step-down pressure on wettability-controlled heterogeneous bubble nucleation of sparingly soluble gases in water

The liberation of dissolved gas from a liquid typically occurs either by diffusion through the gas–liquid interface and/or by bubble nucleation at the solid–liquid interface. The goal of this research was to study the influences of step-down pressure (degree of supersaturation) and wettability on the onset pressure for bubble nucleation of sparingly soluble gases, methane and nitrogen, in water. Bubble nucleation experiments were carried out with the gas-supersaturated liquids in the hydrophilic (untreated) and hydrophobic (treated) glass vials. The gas-saturated liquids were prepared by saturating water with methane or nitrogen in a glass vial placed in a pressure cell at 6,000 mbar for a minimum of 16 or 15 h, respectively. To initiate the pressure-driven bubble nucleation process, 100-, 500-, or 6,000-mbar step-down pressures were applied to the pressure cell until the bubble nucleation was initiated. Bubble nucleation did not occur in the hydrophilic vial with any of the gas-supersaturated waters, irrespective of the step-down pressures. Unexpectedly, 100-mbar step-down pressure did not cause neither methane nor nitrogen bubble nucleation in the hydrophobic vials. Whereas, both methane and nitrogen bubble nucleations occurred in the hydrophobic vials when the step-down pressure was increased to 500 mbar. The above experimental findings revealed the importance of step-down pressure and surface wetting nature on sparingly soluble gas bubble nucleation. To further understand the experimental findings, an analytical method was developed to estimate the effective supersaturations using Fick’s 2nd law of diffusion and Henry’ law, which indicated that at any given pressure the 500-mbar step-down pressure creates higher supersaturation compared to 100-mbar step-down pressure.

A balance among irrigation and fertilization regimes to reduce greenhouse gases emissions from saline and alkaline soils

AbstractAgricultural practices of nitrogen and irrigation overuse bring lots of environmental problems, such as greenhouse gases (GHGs) emissions, soil, and water pollution. With the fast expansion of saline and alkaline agricultural soils in the Tarim River Basin, field practice must be very cautious facing water limitations and global warming. The GHGs were measured 1–2 times weekly and water and fertilizer use efficiency were evaluated under five treatments: (1) fallow (Control); (2) no N (kg N ha−1) and no irrigation (mm) (0N0W); (3) 200 and 355 (LNLW); (4) 230 and 475 (MNMW), and (5) 320 and 655 (HNHW) (traditional treatment) from 2018 to 2019 under maize in Aksu in the Tarim River Basin. The GHGs increased with fertilization and irrigation. The cumulative GHGs were 0.6–5.9 Mg CO2–C ha−1, 0.2–3.6 kg N2O–N ha−1, and increased significantly with biomass increase. The cumulative CH4 was −0.03 to −0.12 kg C ha−1. The MNMW resulted in the highest average water use efficiency (27 kg ha−1 mm−1), irrigation water use efficiency (32 kg ha−1 mm−1), and agronomic N use efficiency (44 kg kg−1), but the lowest greenhouse gas intensity (0.4 kg CO2‐eq ha−1 grain yield). The MNMW reduced the average of 10 mm water, 5 kg N ha−1 fertilizer, and 4 × 10−3 kg CO2‐eq ha−1 GHGI earning 1 t ha−1 maize compared to HNHW. The CO2 emission had a strong relationship with temperature (T) and soil moisture (W) (CO2 emission = (exp (a + bW + cW2)) Q10(T‐20)/10)) (R2 = 0.59–0.92). The lowest was in the LNLW treatment in 2019; the highest was in the HNHW in 2018). The emission of CO2 responding to fertilization was below the global trend, but that of N2O was above under maize in saline and alkaline soils (pH 7–9). In conclusion, MNMW was the best field management to mitigate GHGs with the highest water and fertilizer use efficiency under maize in saline and alkaline soils in Tarim River Basin, where had the higher N2O emission risk.

Imparting durable superhydrophobic/oleophobic properties to wood surfaces by means of PFDMS@MTCS vapor deposition

Wood is prone to absorb water or oil due to the chemical characteristics of its components, which significantly reduces its service performance. Consequently, superhydrophobic or superoleophobic wood has great development potential in the wood industry. We coated methyltrichlorosilane (MTCS) and 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (PFDMS) on Birch wood surfaces by a chemical vapor deposition method. The modified wood showed superhydrophobicity and oleophobicity, with a water contact angle (WCA) of 157.7° and an oil contact angle (OCA) of 141.3°. Due to the large number of low surface energy groups bonded onto the wood surface, it showed extremely strong repulsion to liquid water, oil and even gaseous water. Moreover, the superhydrophobic coating exhibits excellent mechanical and chemical stability and thereby allows long-term use in harsh outdoor environments.

Hygroscopic La2O3 hybridized LaCoO3-based composite catalyst for efficient ozone decomposition under humidity conditions

Herein we first report the unique hygroscopic oxide hybrid LaCoO3-based composite catalyst derived from dual-metal metal organic framework (MOF) for ozone decomposition. First, dual-metal La,Co-MOF is synthesized by solvothermal method, then La,Co-MOF is calcined at high temperature, the hygroscopic oxide (La2O3) and active oxides (LaCoO3 and Co3O4) were uniformly hybridized to form porous microspheres. Benefiting from the hybrid action of the two types of oxides, this composite catalyst exhibits highly efficient O3 removal activity within 12 h over the entire humidity conditions. The outstanding humidity resistance is attributed to the preferential adsorption of water vapor on hygroscopic oxide (La2O3), preventing the adsorption of gaseous water molecules on the surface of active oxides. In-situ FTIR further indicates that this composite catalyst possesses superior humidity resistance in the ozone catalytic decomposition.

Polynitrogen clusters interaction with water: experimental and theoretical perspectives

Polynitrogen clusters are of great interest as potential high-energy-density materials (HEDMs). However, it is still a challenge to effectively manufacture pure nitrogen clusters. Here, we present a method to produce all-nitrogen clusters ranging in size from 3 to 10 using a self-developed apparatus consisting of a laser vaporization cluster source and a mass spectrometer. The results indicate that the mass peak of the N4 + cluster is dominant, and the cooling of the cluster source with liquid nitrogen effectively enhanced the intensities of larger nitrogen clusters. The trace amounts of water in the carrier gas affects the relative signal intensities of nitrogen clusters, suggesting that water molecules can affect their stabilities. The geometrical structures of the N(n = 3–10) clusters are determined by CALYPSO cluster structural search method and density functional theory calculations. A series of promising polynitrogen clusters, such as Z-shaped N clusters and bicyclic N clusters, are identified. The molecular dynamics simulations indicate the decomposition energy barrier of (N4–H2O)+ cluster is lower than that of N4 + cluster by 2.3 kcal mol−1, while the decomposition energy barrier of (N8–H2O)+ cluster is higher than that of N8 + cluster by 1.4 kcal mol−1. These findings provide useful information for the generation and stabilization of polynitrogen clusters, which are valuable for the design and synthesis of HEDMs.

Thermodynamic analysis of the series system for the supercritical water gasification of coal-water slurry

Supercritical water gasification (SCWG) is a potential clean technology for utilizing solid fuel or waste without producing gaseous pollution. Efficient energy integration and recovery strategies play an essential role in the endothermal gasification process. Previous approaches have only focused on the heat source or heat transfer with very little attention to the utilization of the abundant supercritical water in the product gas. This paper proposes an innovative series design for heat integration in the SCWG system while taking the gasification process into account. Notably, the first-stage oxidized hot fluid containing abundant water is directly utilized as the gasification agent for the second-stage gasification reactor. The thermodynamic analysis shows that the cold gas and exergy efficiency in the two-stage series system is 17.4% and 15.0% higher than in the previous single-stage gasification reactor. The sensitivity analysis illustrates that increasing series stages and feedstock concentration while decreasing oxidation proportion and the agent-slurry ratio can improve the overall system efficiency by decreasing the demand for oxygen, power consumption, and heat transfer rate. The series design should offer an innovative and practical approach for the heat supply in the industrial SCWG plant.

The links between marine plastic litter and the air-sea flux of greenhouse gases

Climate change and plastic pollution are two of the most pressing environmental challenges caused by human activity, and they are directly and indirectly linked. We focus on the relationship between marine plastic litter and the air-sea flux of greenhouse gases (GHGs). Marine plastic litter has the potential to both enhance and reduce oceanic GHG fluxes, but this depends on many factors that are not well understood. Different kinds of plastic behave quite differently in the sea, affecting air-sea gas exchange in different, largely unknown, ways. The mechanisms of air-sea exchange of GHGs have been extensively studied and if air-sea gas transfer coefficients and concentrations of the gas in water and air are known, calculating the resulting GHG fluxes is reasonably straightforward. However, relatively little is known about the consequences of marine plastic litter for gas transfer coefficients, concentrations, and fluxes. Here we evaluate the most important aspects controlling the exchange of GHGs between the sea and the atmosphere and how marine plastic litter could change these. The aim is to move towards improving air-sea GHG flux calculations in the presence of plastic litter and we have largely limited ourselves to identifying processes, rather than estimating relative importance.

Design and application of gel coagulation–spontaneous flotation integrated process in water treatment: “Clouds in water”

The gel coagulation–spontaneous flotation (GCSF) process designed in this paper mainly rely on dissolved gas in water rather than auxiliary gas equipment to achieve spontaneous flotation. Compared with the traditional coagulation-dissolved air flotation method, GCSF has more stable flotation efficiency and shorter operation cycle under conventional hydraulic conditions. In this study, the GCSF scheme was applied for surface water treatment, and its operating efficiency, mechanism of action, and environmental implications were explored systematically. The results illustrate that the dosage ratio of sodium alginate (SA) to aluminum sulfate (AS) should be controlled in the range of approximately 1.5:1–2.5:1, and SA should be added 15∼120 s before AS during the coagulation process. Under these conditions, the adsorption cross-linking between SA and Al3+ promoted the generation of gel flocs and effectively encapsulated the dissolved gasses, thereby achieving a stable spontaneous flotation process and 80%–95% removal of pollutants. The purification efficiency of GCSF was positively correlated with pH 4–9, which was attributed to the enhanced hydrophobicity of the chains of organic polymer groups. The residual SA and aluminum concentration in effluent were lower than 1 and 0.05 mg/L, respectively, which guarantee the ecological security of GCSF application. In addition, the results of density functional theory calculations revealed that -OH and -AlO6 in cross-linked flocs could adsorb dissolved oxygen synergistically, while -OH combined with oxygen had a stronger binding energy and stable adsorption.

Investigating States of Gas in Water Encapsulated between Graphene Layers with Transmission Electron Microscopy.

Investigating States of Gas in Water Encapsulated between Graphene Layers with Transmission Electron Microscopy.

Optimum design of a deep cooling tower for waste heat and water recovery from humid flue gas

In order to efficiently recover the waste heat and gaseous water from humid flue gas, a deep cooling tower was designed to explore the heat and mass transfer performance, we optimized the design of tower equipment and absorption heat pump system. The running resistance of total tower is less than 240 Pa, the structured packing can reach the maximum heat transfer power under liquid to gas ratio of 3.5 L/Nm3, 3.0 L/Nm3 and 2.5 L/Nm3, respectively. Under gas velocity of 2.5 m/s, the heat transfer capacity is 54.1–149.2 W m−2 K−1, mass transfer capacity is 0.72–2.02 g m−2 s−1. The coefficient of performance of absorption heat pump can reach 1.71, for a 140 MW boiler, the energy recovery capacity can reach 24 MW and the water recovery capacity can reach 34 m3/h, the emission reductions of CO2, dust, SO2 and NOx can reach 7324 kg/h, 1992 kg/h, 219 kg/h and 109 kg/h, respectively.

Researching Offshore Facilities and Choosing an Appropriate Platform for Hydrate Extraction in the Bay of Bengal

Offshore buildings are used in various locations and sea depths for several reasons. Different equipment, platforms, and design techniques are needed depending on water depth, climatic conditions, structural arrangement, and new concepts. Offshore constructions usually generate and transport oil, gas, and other commodities. Bangladesh has yet to use the Bay of Bengal's hydrocarbon potential for oil and gas. Bangladesh lags behind India and Myanmar in maritime oil and gas discovery. In 50 years, Bangladesh's sea barriers have yielded no benefits. Bangladesh's economy is hindered by its high crude oil imports. Focus on offshore petroleum exploration to locate "black gold" now. Therefore, an offshore structure is needed. This thesis paper covers the fundamentals of all offshore systems, broadens the research, and recommends appropriate platforms for various sea-water depths, which those platforms are meant to be built for hydrates predicted in the Bay of Bengal. The paper uses the Bay of Bengal sedimentation and estimated water depth to choose offshore constructions. The country's maritime boundaries have 26 oil and gas blocks. There are 11 in shallow water and 15 in deep sea. According to statistics, the blocks are on the continental shelf and deep-water region. Five zones make up the Bay of Bengal continental shelf. They are shores A-B, B-C, C-D, D-E, and E-F after region F continental slope continues till the deep sea area. The continental slope zone C-D has 64-106 m water depth. Therefore, the Bay of Bengal continental shelf is suitable for all permanent offshore buildings except this zone. Only concrete gravity platforms fit this zone. We need the technology to search for oil and gas in water. It takes a lot of work to get foreign companies to work together. Thus, skilled people should work on it and encourage government or private businesses to develop oil and gas production technology.

Scalable micro/nanostructured superhydrophobic surface modifications for enhanced energy efficiency and heat transfer performance in stainless steel and titanium

Condensation refers to the change of a substance from a gaseous phase to a liquid phase, an example of which is the condensation of water vapor in nature. Condensation is used in many industries, such as energy generation and seawater desalination. On a general surface, filmwise condensation is the main phenomenon in which gaseous water vapor is condensed in the form of a film. However, film condensation acts as a factor that reduces energy efficiency as the liquid film formed on the surface interferes with heat transfer. A phenomenon opposite to film condensation is dropwise condensation, which is immediately separated after condensation in the form of droplets, and thus a film is not formed, greatly improving heat transfer efficiency. Because of these advantages, many studies have been conducted, and most studies have induced dropwise condensation by modifying the surface to be superhydrophobic. However, in the case of a superhydrophobic surface, it takes a lot of time and money in the process, so there is a great difficulty in increasing the area. Among them, stainless steel and titanium, which are most materials for industrial heat exchangers, have high robustness, so there are few studies on improving the condensation performance after surface modification due to the difficulty of processing. For this reason, there is a large gap between the currently conducted studies and the actual industry. Our research team succeeded in modifying the surface of a stainless steel and titanium tube the size of an actual heat exchanger into superhydrophobicity with a simple process. We confirmed that the condensation performance was improved on the superhydrophobic surface through experiments under various conditions. By comparing the improvement in the heat transfer performance of stainless steel and titanium under several conditions, the main cause of the performance improvement was proved. This study is expected to play a major role in the eco-friendly future industry where energy efficiency is important by improving the heat transfer performance of stainless steel and titanium, which are mainly used throughout the industry.

Self-consistent Models of Y Dwarf Atmospheres with Water Clouds and Disequilibrium Chemistry

Y dwarfs are the coolest spectral class of brown dwarf. They have effective temperatures less than 500 K, with the coolest detection as low as ∼250 K. They make up the low-mass tail of the star formation process, and are a valuable analog to the atmospheres of giant gaseous exoplanets in a temperature range that is difficult to observe. Understanding Y dwarf atmospheric compositions and processes will thus deepen our understanding of planet and star formation and provide a stepping stone toward characterizing cool exoplanets. Their spectra are shaped predominantly by gaseous water, methane, and ammonia. At the warmer end of the Y-dwarf temperature range, spectral signatures of disequilibrium carbon monoxide have been observed. Cooler Y dwarfs could host water clouds in their atmospheres. JWST spectral observations are anticipated to provide an unprecedented level of detail for these objects, and yet published self-consistent model grids do not accurately replicate even the existing Hubble Space Telescope and ground-based observations. In this work, we present a new suite of 1D radiative-convective equilibrium models to aid in the characterization of Y-dwarf atmospheres and spectra. We compute clear, cloudy, equilibrium chemistry and disequilibrium chemistry models, providing a comprehensive suite of models in support of the impending JWST era of panchromatic Y-dwarf characterization. Comparing these models against current observations, we find that disequilibrium CH4–CO and NH3–N2 chemistry and the presence of water clouds can bring models and observations into better, though still not complete, agreement.

Acid gas preparation for enhanced oil recovery: techno-economic analysis of different dehydration processes

ABSTRACT The natural gas treatment plant is one source of CO2 emissions into the atmosphere. To tackle this issue, it is probable to inject CO2 into the wells and it can be used for enhanced oil recovery (EOR) application. However, the main setback is the high content of water in acid gas that could be converted to hydrate at high pressure in the pipelines. In this article, two different processes (solvent extraction, stripping gas) with two different solvents mono ethylene glycol (MEG), Tri ethylene glycol (TEG), are simulated in Aspen HYSYS. The stripping gas method is more efficient in terms of energy consumption, consuming 31.8% and 56.8% less energy than solvent extraction method for MEG and TEG solvents, respectively. Hydrate formation analyses showed that applying MEG as a solvent in the stripping gas method leads to a safer operation region. Economic evaluation depicts that the stripping gas method saves the total annual cost by 22.2% compared to solvent extraction.

Determination of the radon transfer velocity coefficient in water under static and turbulent conditions

The risk associated with the inhalation of radon gas has prompted numerous studies analyzing its behavior and transport from its generating source (soil, water or building materials) to its accumulation in enclosed spaces. In this research, the process of radon gas release from water to air in hermetically sealed equipment and under controlled conditions at laboratory scale is analyzed.The experimental measurements have been later processed and analyzed by an iterative algorithm, based on the minimization of the squared error, to develop a dynamic model through which the transfer velocity coefficient (k) is obtained in different test conditions. From the experimental results and the dynamic model a coefficient of (1.4 ± 0.14)·10−3 m h−1 is obtained for static water conditions and (2.4 ± 0.6)·10−3 m·h−1for turbulent water. It is verified that the escape process of radon gas in water is slower when it is in a static state, without turbulence. Finally, the coefficient is validated by calculating the estimated radon concentration evolution in air, which in turn is compared with the experimental results.

Subambient temperature swing adsorption utilizing cold energy from liquefied natural gas

This study proposes a CO2 capture process by temperature swing adsorption (TSA) using latent heat of evaporation for liquefied natural gas (LNG) as a cold energy source, which is currently unused and discarded into seawater. The proposed subambient process has several advantages: (1) the total energy cost can be saved by the LNG cold energy; (2) the equilibrium capacity of CO2 at subambient temperature can be increased substantially; and (3) water in the flue gas which would lead to deterioration of the adsorbent can be removed by a pretreatment step utilizing LNG cold energy. For the adsorbent in the TSA system, zeolite 13X, MIL-101, UiO-66, and CPL-1, which are considered effective for CO2 adsorption in the subambient, were considered and adsorption isotherm data were obtained at subambient conditions. Comparisons of these adsorbents were carried out using a rigorous dynamic model of the TSA process. It was found that CPL-1 gives a high recovery rate of 70% and purity of 95%. It was also found that the proposed system has the potential to capture up to 6% of the CO2 emitted from Japan.