Conventional Gas Research Articles

CO2 Adsorption in a Robust Iron(III) Pyrazolate-Based MOF: Molecular-Level Details and Frameworks Dynamics From Powder X-ray Diffraction Adsorption Isotherms.

Understanding adsorption processes at the molecular level, with multi-technique approaches, is nowadays at the frontier of porous materials research. In this work it is shown that with a proper data treatment, in situ high-resolution powder X-ray diffraction (HR-PXRD) at variable temperature and gas pressure can reveal atomic details of the accommodation sites, the framework dynamics as well as thermodynamic information (isosteric heat of adsorption) of the CO2 adsorption process in the robust iron(III) pyrazolate-based MOF Fe2(BDP)3 [H2BDP = 1,4-bis(1H-pyrazol-4-yl)benzene]. Highly reliable "HR-PXRD adsorption isotherms" can be constructed from occupancy values of CO2 molecules. The "HR-PXRD adsorption isotherms" accurately match the results of conventional static and dynamic gas sorption experiments and Monte Carlo simulations. These results are indicative of the impact of the molecular-level behavior on the bulk properties of the system under study and of the potential of the presented multi-technique approach to understand adsorption processes in metal-organic frameworks.

Improved NO2 gas sensing performance of nanoporous conjugated polymer (CP) thin films by incorporating preformed CP nanowires

Conjugated polymer (CP)-based organic field-effect transistor (OFET) gas sensors can detect gas molecules at room temperature with high sensitivity and selectivity. However, their performance, particularly when detecting oxidizing gases, has fallen behind that of their metal oxide counterparts. Hence, improving their sensing performance as well as understanding the correlation between it and the structural and electrical properties of the sensing materials is necessary. Herein, we demonstrate that gas sensing performance of an OFET sensor based on nanoporous poly(3-hexylthiophene) (P3HT) films can be improved simply by incorporating preformed P3HT nanowires (NWs), which act as an efficient charge transport pathway. It detects nitrogen dioxide (NO2) molecules with high sensitivity due to the efficient charge transport pathway as well as ultrathin nanoporous structure of the P3HT films. Upon exposure to 10 ppm NO2 at room temperature, the OFET gas sensor based on the P3HT-NW embedded nanoporous P3HT film exhibits excellent responsivity (34%), fast response and recovery times (∼69 and ∼133 s, respectively), and a low limit of detection of under 0.1 ppm, which are comparable to those of conventional metal oxide-based gas sensors. Based on the correlation study between the morphology, charge transport ability, and sensing performance of the P3HT-NWs embedded nanoporous P3HT films, it is revealed that the efficient charge transport ability is an important factor for realizing high-performance CP-based OFET gas sensors, along with excellent morphological features such as thinness and high pore density.

Visual Blood, Visualisation of Blood Gas Analysis in Virtual Reality, Leads to More Correct Diagnoses: A Computer-Based, Multicentre, Simulation Study.

Interpreting blood gas analysis results can be challenging for the clinician, especially in stressful situations under time pressure. To foster fast and correct interpretation of blood gas results, we developed Visual Blood. This computer-based, multicentre, noninferiority study compared Visual Blood and conventional arterial blood gas (ABG) printouts. We presented six scenarios to anaesthesiologists, once with Visual Blood and once with the conventional ABG printout. The primary outcome was ABG parameter perception. The secondary outcomes included correct clinical diagnoses, perceived diagnostic confidence, and perceived workload. To analyse the results, we used mixed models and matched odds ratios. Analysing 300 within-subject cases, we showed noninferiority of Visual Blood compared to ABG printouts concerning the rate of correctly perceived ABG parameters (rate ratio, 0.96; 95% CI, 0.92-1.00; p = 0.06). Additionally, the study revealed two times higher odds of making the correct clinical diagnosis using Visual Blood (OR, 2.16; 95% CI, 1.42-3.29; p < 0.001) than using ABG printouts. There was no or, respectively, weak evidence for a difference in diagnostic confidence (OR, 0.84; 95% CI, 0.58-1.21; p = 0.34) and perceived workload (Coefficient, 2.44; 95% CI, -0.09-4.98; p = 0.06). This study showed that participants did not perceive the ABG parameters better, but using Visual Blood resulted in more correct clinical diagnoses than using conventional ABG printouts. This suggests that Visual Blood allows for a higher level of situation awareness beyond individual parameters' perception. However, the study also highlighted the limitations of today's virtual reality headsets and Visual Blood.

Gastro-protective Effect of Carica papaya Leaf Extracts on Ethanol-Induced Gastric Ulcer in Rats

Carica papaya leaves are commonly used traditionally to treat many diseases, including peptic ulcers; however, these pharmacological claims and safety issues of the leaves have not been adequately resolved. The present study aims to evaluate the possible gastro-protective potential of Carica papaya aqueous and methanol leaf extracts on ethanol-induced ulcers. Aqueous and Methanol extracts of C. papaya were prepared by percolation method and screened for phytochemicals using conventional method and Gas Chromatography-Mass spectrometric methods. The gastro-protective effects of the extracts were determined using thirty (30) rats weighing 180 and 250 g were randomly divided into five groups. Group 1 served as the normal control (distilled water), groups 2 served as the (negative control), group 3 received 25mg/kg Omeprazole (standard drug) group 4 and 5 received 300 mg/kg and 600 mg/kg of aqueous and methanol extracts of Carica papaya. Two weeks after the oral administration, gastric ulcer was induced in all rats with 95% ethanol (2 mL). The aqueous and methanol leaf extract of C. papaya showed a significant (p&lt;0.05) dose-dependent protection against peptic ulcer. The effects produced by the methanol leaf extract of C. papaya were comparable to those of the standard drugs (Omeprazole). Phytochemical analysis of the aqueous and methanol leaves extracts of C. papaya revealed the presence of flavonoids, tannins, alkaloids, terpenoids, cardiac glycosides, reducing sugar and saponins, some of which have been reported to elicit cytoprotective effect. Gas chromatographic analysis showed the presence of cytoprotective agents. These findings show that aqueous and methanol extracts of the leaves of C. papaya possess potent antiulcer properties; hence justifies the traditional usage of this plant for ulcer treatment.

Progress of Seepage Law and Development Technologies for Shale Condensate Gas Reservoirs

With the continuous development of conventional oil and gas resources, the strategic transformation of energy structure is imminent. Shale condensate gas reservoir has high development value because of its abundant reserves. However, due to the multi-scale flow of shale gas, adsorption and desorption, the strong stress sensitivity of matrix and fractures, the abnormal condensation phase transition mechanism, high-speed non-Darcy seepage in artificial fractures, and heterogeneity of reservoir and multiphase flows, the multi-scale nonlinear seepage mechanisms are extremely complicated in shale condensate gas reservoirs. A certain theoretical basis for the engineering development can be provided by mastering the percolation law of shale condensate gas reservoirs, such as improvement of productivity prediction and recovery efficiency. The productivity evaluation method of shale condensate gas wells based on empirical method is simple in calculation but poor in reliability. The characteristic curve analysis method has strong reliability but a great dependence on the selection of the seepage model. The artificial intelligence method can deal with complex data and has a high prediction accuracy. Establishing an efficient shale condensate gas reservoir development simulation technology and accurately predicting the production performance of production wells will help to rationally formulate a stable and high-yield mining scheme, so as to obtain better economic benefits.

Proposal of Zero-Emission Tug in South Korea Using Fuel Cell/Energy Storage System: Economic and Environmental Long-Term Impacts

This study presents the results of economic and environmental analysis for two types of zero-emission ships (ZESs) that are receiving more attention to meet strengthened environmental regulations. One of the two types of ZES is the ZES using only the energy storage system (All-ESS), and the other is the ZES with fuel cell and ESS hybrid system (FC–ESS). The target ship is a tug operating in South Korea, and the main parameters are based on the specific circumstances of South Korea. The optimal capacity of the ESS for each proposed system is determined using an optimization tool. The total cost for a ship’s lifetime is calculated using economic analysis. The greenhouse gas (GHG) emission for the fuel’s lifecycle (well-to-wake) is calculated using environmental analysis. The results reveal that the proposed ZESs are 1.7–3.4 times more expensive than the conventional marine gas oil (MGO)-fueled ship; however, it could be reduced by 1.3–2.4 times if the carbon price is considered. The proposed ZESs have 58.7–74.3% lower lifecycle GHG emissions than the one from the conventional ship. The results also highlight that the electricity- or hydrogen-based ZESs should reduce GHG emissions from the upstream phase (well-to-tank) to realize genuine ZESs.

Wellbore and Reservoir Thermodynamic Appraisal in Acid Gas Injection for EOR Operations

This study provides insights into the experience gained from investigating the thermodynamic behavior of well and reservoir fluids during acid gas injection (AGI) in a hydrocarbon field to enhance oil recovery (EOR) and to reduce greenhouse gas emissions. Unlike conventional water and natural gas injection, AGI involves complicated phase changes and physical property variations of the acid gas and reservoir fluids at various pressure-temperature (P-T) conditions and compositions, and both constitute crucial parts of the EOR chain. A workflow is developed to deal with the reservoir fluid and acid gas thermodynamics, which is a key requirement for a successful design and operation. The workflow focuses firstly on the development of the thermodynamic models (EoS) to simulate the behavior of the reservoir fluids and of the injected acid gas and their integration in the field and in well dynamic models. Subsequently, the workflow proposes the thermodynamic simulation of the fluids’ interaction to determine the Minimum Miscibility Pressure (MMP), yielding the dynamic evolution of the fluids’ miscibility that may appear within the reservoir. Flow assurance in the acid gas transportation lines and in the wellbore is also considered by estimating the hydrate formation conditions.

Multidimensional Gas Chromatography of Organosulfur Compounds in Coffee and Structure-Odor Analysis of 2-Methyltetrahydrothiophen-3-one.

Organosulfur compounds (OSCs) in coffee remain challenging to analyze by conventional gas chromatography (GC) due to their low concentrations amid coffee's complex matrix and susceptibility to chiral-odor influences. In this study, multidimensional GC (MDGC) methods were developed to profile OSCs in coffee. Conventional GC was compared to comprehensive GC (GC×GC) for untargeted OSC analysis in eight specialty coffees, and GC×GC was found to improve the fingerprinting of OSCs in coffee (50 vs 16 OSCs identified). Of the 50 OSCs, 2-methyltetrahydrothiophen-3-one (2-MTHT) was of high interest due to its chirality and known aroma contribution. Following that, a heart-cutting method for chiral GC (GC-GC) was developed, validated, and applied to the coffees. The mean enantiomer ratio of 2-MTHT was observed to be 1.56 (R/S) in brewed coffees. Overall, MDGC techniques allowed for more comprehensive analyses of coffee OSCs, from which (R)-2-MTHT was found to be the predominant enantiomer with the lower odor threshold.

A comparative study of the entropy generation by an integrated fuel cell-intercooled gas turbine

Lower efficiency and a lower maximum output are causing problems for conventional gas turbine power plants. Additionally, the emission is the major issue that causes the global warming. Either modifying its settings or integrating it with another system will allow for an increase in productivity. With the goal of increasing efficiency and decreasing emissions, this paper describes how fuel cells can be combined with traditional ICGTs. Fuel cell is an electrochemical device which converts chemical energy to electrical energy and generates additional power. The high temperature fuel cell, a SOFC (Solid Oxide Fuel Cell) is integrated with the conventional ICGT cycle. The maximum level of irreversibility in a system can be identified with the use of exergy analysis and energy analysis. The maximum irreversibility is observed in the combustion chamber 55.1% in hybrid configuration and 47.3% in non-hybrid configuration. There is a 65.789% and 167.801% increase in energy and exergy efficiency, respectively. The environmental effect of the cycle is determined by evaluating the sustainability index, which is 100.78% greater for the hybrid cycle compared to non-hybrid cycle.

Conventional Natural Gas Project Investment and Decision Making under Multiple Uncertainties

Similar to many energy projects, the evaluation of investments in natural gas projects is influenced by technical and economic uncertainties. These uncertainties include natural resource characteristics, production, decline laws, prices, taxes, benchmark yield, and so on. In China, conventional natural gas is still the dominant energy source. The investors are mainly large state-owned energy companies. Therefore, it is necessary to include the technical and economic uncertainties, as well as the investment decision and optimization problems of the enterprises in a unified analytical framework. To this end, this paper innovatively constructs such a framework. Using numerical simulations of approaches, the process of investment decision optimization by companies based on technology assessment and price forecasting is visualized in detail. The results suggest that the investment decision of the enterprise needs to consider technical and economic uncertainties in an integrated manner. It also needs to combine the business strategy and social responsibility of the enterprise in order to construct the objective function. With the availability of data, the framework and its algorithms can be used for practical evaluation of investment plans and decision supports for conventional natural gas projects. The framework can also integrate the analytical perspective of the macroeconomic and political environment to bring in a more comprehensive range of uncertainties.

Laminar Burning Velocity, Adiabatic Flame Temperature, and Pollutants of Biogas/Air Mixture at Various CO2 Concentrations and Plasma Assist

ABSTRACT Mixtures of CH4 and CO2, known as biogas, are considered as renewable gas with low heat energy, which makes it extremely difficult to use as fuel in conventional natural gas equipment. To better understand the behavior of biogas mixtures and their properties, numerical results of the impact of carbon dioxide on laminar burning velocity and flame temperature of methane (CH4)–carbon dioxide (CO2)–air combustion were done. One of the most promising methods to enhance combustion is the use of a plasma source to assist unstable flames. For this purpose, experimental results to investigate the effect of microsecond pulsed plasma on non-premixed biogas flames were conducted. In the first section, laminar burning velocities and adiabatic flame temperature have been numerically calculated by one-dimensional steady code using several chemical kinetic mechanisms. Numerical results were compared with several experimental results from the literature. The laminar burning velocity and the adiabatic temperature of biogas/air combustion were calculated with CO2 concentration ranging from 0% to 50% in the mixture. The equivalence ratio was varied from 0.4 to 1.4, the initial pressure was set at 1 bar, and the temperature was set to 300 K. The impact of CO2 addition on the CO and NOx emissions at equivalence ratios from lean to rich (0.4–1.4) was investigated. It was found that increasing CO2 in the biogas lowers NOx and increases CO. In the second section, the effects of microsecond pulsed plasma on non-premixed swirling biogas/air flames were experimentally investigated. The plasma-assisted combustion was carried out in a coaxial burner. It consists of two concentric tubes; the central tube delivers the biogas flow to the injector and the annular tube contains a swirler and supplies the airflow. To create plasma in the stabilization zone of the flame, a rod-ring microsecond plasma configuration was used. OH* chemiluminescence measurements are used to describe the structure and stability of the flame. Results showed that plasma generated by microsecond high-voltage (HV) pulses can improve flame stability. An analysis of the optical emission spectra (OES) showed that plasma generates chemically active species such as excited N2*, CH*, OH* molecules, and H* atoms, leading to improved flame stability. The dependence of their intensities on both the pulse repetition frequency (PRF) and the input electrical voltage was investigated. The gas analysis of the exhaust gas was carried out with and without plasma. The exhaust gas concentration measurements revealed that the rod-ring pulsed plasma reduces CO with a low impact on the NOx level.

One-dimensional and comprehensive two-dimensional gas chromatographic approaches for the characterization of post-consumer recycled plastic materials

In September 2022, the European Commission published its new regulation on recycled plastic materials for food contact. It allows newly developed, non-authorized technologies and approaches, or so-called novel technologies, to be deployed in the field to generate the data needed for establishing regulatory and/or fit for purpose processes. The data shall be generated by using suitable methods, but the regulation does not give a more detailed description on those. In this study, commercially purchased buckets made of post-consumer recycled polypropylene were screened, using a number of different analytical approaches. Sample preparation methods, analysis techniques, and the data and information generated were compared. The results clearly demonstrate the need for a detailed characterization of such materials and the advantages and disadvantages of the analysis using conventional gas chromatography with flame ionization detection and mass spectrometery as well as two-dimensional comprehensive gas chromatography with time of flight mass spectrometry.Graphical

Economic Performance Indicators for a Geothermal Aquatic Center in Victoria, Australia

The Gippsland Regional Aquatic Centre (GRAC) opened in the town of Traralgon, Victoria, Australia early in 2021. The GRAC utilizes a geothermal energy heating system as an alternative to conventional natural gas furnaces. We have examined 12 full months of heat production from the geothermal system of the GRAC and compared its economic performance against equivalent heat production by natural gas. The geothermal system—the first of its kind in Victoria—operated at &gt;95% availability over its first year of operation. Our economic assessment indicates that the breakeven price for the geothermal energy is about 35% the equivalent price of natural gas and the payback period for the geothermal system is about five years. The results justify the initial capital outlay by Latrobe City Council and are likely to stimulate further development of geothermal heat systems in the region.

Formation of Artificial Fermi Surfaces with a Triangular Superlattice on a Conventional Two-Dimensional Electron Gas.

Imposing an external periodic electrostatic potential to the electrons confined in a quantum well makes it possible to engineer synthetic two-dimensional band structures, with electronic properties different from those in the host semiconductor. Here we report the fabrication and study of a tunable triangular artificial lattice on a GaAs/AlGaAs heterostructure where it is possible to transform from the original GaAs band structure and a circular Fermi surface to a new band structure with multiple artificial Fermi surfaces simply by altering a gate bias. For weak electrostatic modulation magnetotransport measurements reveal multiple quantum oscillations and commensurability oscillations due to the electron scattering from the artificial lattice. Increasing the strength of the modulation reveals new commensurability oscillations of the electrons from the artificial Fermi surface scattering from the triangular artificial lattice. These results show that low disorder gate-tunable lateral superlattices can be used to form artificial two-dimensional crystals with designer electronic properties.

Carbon-neutral hydrogen production from natural gas via electrified steam reforming: Techno-economic-environmental perspective

This study proposes and evaluates a novel carbon-neutral hydrogen (H2) production process from natural gas through electrified steam methane reforming (e-SMR) with renewable electricity. The process model consists of different unit technologies such as reforming, water–gas shift, hydrogen pressure swing adsorption, and CO2 capture, along with heat recovery. Then, we evaluated the techno-economic-environmental performance of the proposed e-SMR process by comparing it with the conventional fired-heating steam methane reforming (f-SMR). By employing an electrically driven reformer using renewable energy, e-SMR outperforms f-SMR with less natural gas consumption, higher energy efficiency of 78.7%, and lower net CO2eq emission of 5.28 kg CO2eq/kg H2 and captured 5.58 kg CO2/kg H2; however, it has a drawback, i.e., higher H2 unit production cost (UPC) of 3.49 $/kg with a capacity of 7.06 ton/day. Sensitivity and uncertainty analyses identified the major cost drivers of UPC, such as the prices of natural gas, renewable electricity, and interest rates, as well as economic risks and uncertainties. The economic viability of e-SMR was determined by investigating multiple plant capacities, natural gas markets, renewable energy prices, and possible future CO2 selling prices. According to the investigation, currently, the US and India show promise for e-SMR, with abundant and affordable natural gas and renewable energy resources, both priced at around 3.49 $/kg of H2, respectively. Furthermore, the global 2030's scenario with 45 $/MWh of renewable electricity, and capture CO2 credit of 35 $/ton is observed at 3.40 $/kg H2, compared with that of 2050 at 2.91 $/kg H2. e-SMR is well adaptable to many countries' energy mix because it is flexible to utilize hybrid primary energy input, conventional natural gas as feedstock, and conventional/renewable energy for utilities.

Preparation of OH/TiO2/PES composite membrane by a novel gas-phase hydrolysis method in gas-liquid membrane contactor to improve the separation efficiency of CO2 and CH4

Conventional gas separation methods are very limited for CO2 separation in terms of separation efficiency and cost. In this study, We obtained fluorinated TiO2/polyethersulfone (PES) composite membranes by gas-phase hydrolysis and compared the characterization results with the composite membranes prepared by the graft coating method. In the mixed gas separation experiment, we used diethanolamine (DEA) as the absorbent to test the separation performance of CO2/CH4 using the composite membranes prepared by gas phase hydrolysis in a gas-liquid membrane contactor (GLMC) system. DEA flow rate and concentration and feed gas flow were found to have a significant effect on separation performance. When the feed gas flow rate was kept constant at 30 ml/min and the DEA flow rate and concentration were 16 L/h and 1 mol/L, respectively, the collected CH4 concentration was 99.4 %. Meanwhile, the CO2 flux was 10.096 × 10−3 mol m−2 s−1, and the separation factor reached 110.444. Collectively, the application of TiO2/PES composite membranes in GLMC is an efficient method for CO2 capture and mixed gas separation.

Drill Cuttings Disposal Efficiency in Offshore Oil Drilling

The relevance of the study lies in the fact that with the depletion of conventional oil and gas reserves and an increase in the global demand for hydrocarbons, the focus of the industrial sector is gradually shifting towards the resources of the Arctic, which have tremendous potential for development. However, the current industrial policy has to take into account the concept of sustainable development, or harmony between economy, ecology, and society. Therefore, the extraction of raw materials must obey the principles of the circular economy, which aims to generate closed-loop cycles that maximize the use of the resources extracted and minimize waste generation so as not to destroy fragile ecosystems. It is necessary to drill wells for the discovery of a hydrocarbon deposit on the shelf, which entails the generation of a tremendous amount of complex waste., The use of disposal methods for drilling cuttings, which must be disposed of economically and with environmental reliability, is required to solve the problem. This study compares two methods of disposing of drilling waste. Statistical modeling results and a review of the literature show that the most effective method from both economic and environmental points of view is the thermomechanical cleaning of cuttings on site. This article discusses the advantages and disadvantages of both methods. It also evaluates drilling waste management prospects and opportunities for Russian offshore fields.

Editorial: Multiphase flow behavior in the deep-stratum and deep-water wellbores

state, heat/mass transfer between gas and liquid, and fluid hydrodynamics in the wellbore depend highly on the temperature and pressure conditions, the multiphase flow behaviors in deep-stratum and deep-water wellbores become much more complicated. Different from the conventional oil and gas exploitation, the production of oil and gas from the and deep stratum deep-water regions involves multiple complex physical phenomena, such as phase transition (gas-liquid-solid-supercritical), particle deposition (wax, hydrate, water scale, asphaltene, etc.), changes of heat/mass transfer induced by phase change, and so on. It is, therefore, of high importance to discuss the multiphase flow behavior in the deep-stratum and deep-water wellbores. This Research Topic aims to explore recent developments in this area and focused on the following two aspects: 1) Numerical simulations of gas-liquid or liquid-solid two-phase flow in porous media, 2) Experiments and simulations of multiphase flow in the pipelines and wellbores. There are a total of 12 articles under this Research Topic.

Whole petroleum system and ordered distribution pattern of conventional and unconventional oil and gas reservoirs

Whole petroleum system and ordered distribution pattern of conventional and unconventional oil and gas reservoirs

Theory and practice of unconventional gas exploration in carrier beds: Insight from the breakthrough of new type of shale gas and tight gas in Sichuan Basin, SW China

Unconventional gas in the Sichuan Basin mainly includes shale gas and tight gas. The development of shale gas is mainly concentrated in the Ordovician Wufeng Formation–Silurian Longmaxi Formation, but has not made any significant breakthrough in the Cambrian Qiongzhusi Formation marine shale regardless of exploration efforts for years. The commercial development of tight sandstone gas is mainly concentrated in the Jurassic Shaximiao Formation, but has not been realized in the widespread and thick Triassic Xujiahe Formation. Depending on the geological characteristics of the Qiongzhusi Formation and Xujiahe Formation, the feedback of old wells was analyzed. Then, combining with the accumulation mechanisms of conventional gas and shale gas, as well as the oil/gas shows during drilling, changes in production and pressure during development, and other characteristics, it was proposed to change the exploration and development strategy from source and reservoir exploration to carrier beds exploration. With the combination of effective source rock, effective carrier beds and effective sandstone or shale as the exploration target, a model of unconventional gas accumulation and enrichment in carrier beds was built. Under the guidance of this study, two significant results have been achieved in practice. First, great breakthrough was made in exploration of the silty shale with low organic matter abundance in the Qiongzhusi Formation, which breaks the traditional approach to prospect shale gas only in organic-rich black shales and realizes a breakthrough in new areas, new layers and new types of shale gas and a transformation of exploration and development of shale gas from single-layer system, Longmaxi Formation, to multi-layer system in the Sichuan Basin. Second, exploration breakthrough and high-efficient development were realized for difficult-to-produce tight sandstone gas reserves in the Xujiahe Formation, which helps address the challenges of low production and unstable production of fracture zones in the Xujiahe Formation, promote the transformation of tight sandstone gas from reserves without production to effective production, and enhance the exploration and development potential of tight sandstone gas.