Primary Gas Research Articles

Pyrolytic kinetics, reaction models and gas evolution of wood material with kerosene by TG-FTIR

The pyrolysis process of typical oils (kerosene, gasoline, etc) penetrating solid combustibles is one of the key behaviors of arsons and fire accidents caused by the leaking and spilling of these flammable oils on solid combustibles. Previous researches have mainly focused on the combustion characteristics of combustible solids infiltrated with flammable oils. However, there is a lack of comprehensive and systematic research on their pyrolysis characteristics, kinetics, and gaseous products. This study explored the pyrolytic behaviors, kinetics, reaction models and pyrolytic gases of pine wood with different contents (0, 5, 10, 20 and 30 wt%) of kerosene via thermogravimetry-Fourier transform infrared analysis (TG-FTIR). The results exhibit that the thermal decomposition processes of the pure pine wood and pine wood-kerosene mixture both show a three-stage process. The average activation energy of the mixture pyrolysis gradually decreases from 181.87 to 129.87 kJ/mol with the increase of kerosene content. The results further identify that the kinetic process of mixtures pyrolysis in the region 2 followed the three-dimensional diffusion model: g(α)= [1 − (1 − α)1/3]2. The principal finding of this study is that the obtained kinetic parameters of mixtures pyrolysis can precisely reproduce and predict conversion degree curves. Moreover, during the pyrolysis of the mixtures, the primary gaseous products identified include H2O, hydrocarbon, CO2, CO, carbonyl compounds, phenols, hydroxyl compounds. As the kerosene content increases, there is a significant rise in the production of hydrocarbons observed at the initial peak (around 420 K). Additionally, the predominant gaseous product observed at the peak temperature is carbonyl compounds. It is expected that this study can provide a practical guideline for the prediction of the fire size, the prevention and control of arson accidents and accident investigation.

Phase behavior and GOR evolution using a natural maturity series of lacustrine oil-prone shale: Implications from compositional modelling

For the exploration of shale oil, there is still an urgent need to relate hydrocarbon generation reactions and changing phase behavior to exact levels of thermal maturity. Six organic-rich shale samples from the Cretaceous Qingshankou Formation, Songliao Basin spanning the maturity range with vitrinite reflectance (Ro) 0.58%–1.16% were studied for petroleum generation characteristics using the PhaseKinetics, PhaseSnapshot, and GORFit approaches. All samples show very good petroleum potential and contain Type I kerogen with total organic carbon contents ranging between 1.5% and 5%. A full spectrum of light to heavy hydrocarbons, consistent with live oils, occurs in thermal extracts of all samples. Gas chromatography fingerprints of samples with Ro > 0.7% closely resemble waxy oils derived from lacustrine organic matter (OM); fingerprints of lower maturity samples are not yet as wax rich. The inferred petroleum type organofacies of all samples is paraffinic high wax with low organic sulfur levels. Hydrocarbon generation from the least mature sample is characterized by one dominant activation energy at 55 kcal/mol, accounting for 87% of the total bulk reaction. Assuming a simplified geological scenario, i.e., a 3 K/My linear heating rate, primary petroleum is generated (transformation ratio, i.e., TR: 10%–90%) over a narrow temperature interval of only 23 °C. Onset (10% TR), maximum (Tpeak), and completion (90% TR) temperatures and Ro values are 141 °C at Ro 0.85%, 155 °C at Ro 1.08%, and 164 °C at Ro 1.2%, respectively. Primary gas generation (148–172 °C) occurs 10 °C later (300 m deeper) than the generation of C6+ compounds (138–161 °C). Secondary gas formation from oil cracking begins at 182 °C, maximizes at 197 °C, and is completed well before 225 °C (beginning of late gas generation from the secondary cracking of thermally matured, macromolecular organic matter) at 206 °C. Thus, primary and secondary oil cracking processes do not overlap under geological conditions. In line with a paraffinic high-wax oil petroleum type organofacies, cumulative fluids generated from the least mature sample fall within the black oil class over most of the primary kerogen conversion range up to 90% TR as indicated by low saturation pressures (Psat) and gas-oil-ratios generally below 160 Sm3/Sm3. Maturation results in relatively heavy fluids with Psat values in the range 40–70 bar when the free hydrocarbons, i.e., already present prior to pyrolysis, are included, and in lighter fluids with Psat values in the range 70–90 bar, when the free, mostly waxy hydrocarbons, are excluded. Systematics of physical properties and fluid compositions evolution reproduce the general behavior of naturally occurring petroleum sourced from lacustrine OM very well and fit physical properties and compositions of produced shale oils in the Songliao Basin at comparable maturity levels.

Geological conditions and controls on accumulation of tight sandstone gas, deep part of the Shengbei sub-sag, Turpan-Hami basin, NW China

With the further exploration of the Jurassic strata in the Turpan-Hami Basin, the targets for hydrocarbon exploration have been gradually shifted from the tectonic belts around sags to the proximal lithological zones of deep sags. Based on the systematic coring of the first exploration well (well Qintan-1) in the center Shengbei sub-sag, this study conducted experiments of organic carbon, pyrolysis, gas chromatography (GC), nuclear magnetic resonance (NMR), and low-temperature nitrogen adsorption. Then, this study systematically analyzed the geological conditions and major controlling factors for the accumulation of tight sandstone gas in the deep part of the Shengbei sub-sag. The results show that: (1) Multiple sets of coal-measure source rocks have developed in the Jurassic strata in the center Shengbei sub-sag, providing plenty of gas sources for multilayered hydrocarbon accumulation; (2) Tight sandstones have poor physical properties and complex pore structures. However, high-permeability zones and anomalous zones of nano-scale pores have developed in the deep part, providing favorable spaces for the accumulation and preservation of tight oil and gas in the deep part; (3) Compaction and late carbonate cementation are key factors in reservoir densification. The microscopic storage space and connectivity of the tight sandstone reservoirs in the Shengbei sub-sag were improved due to the dissolution of fluids in coal measure strata. The occurrence of high-quality reservoirs in the Shengbei sub-sag is significantly controlled by source rocks, and both the former and the latter are characterized by adjacent sources and reservoirs and short-distance migration and accumulation. Furthermore, the special geological phenomena of chert cementation, abnormally high homogenization temperatures of fluid inclusions, and abnormal pyrolysis parameters confirm the presence of low-temperature hydrothermal activity in the deep part of the target strata. Therefore, the center Shengbei sub-sag has geological conditions for the large-scale accumulation of primary gas and, thus, is a key area for future hydrocarbon exploration.

Isotopic comparison of ammonium between two summertime field campaigns in 2013 and 2021 at a background site of North China

Ammonia (NH3) is the primary atmospheric alkaline gas, playing a crucial role in the atmospheric chemistry. Recently, non-agricultural emissions have been identified as the dominant sources of NH3 in urban areas. However, few studies have quantified the contributions of different sources to regional NH3. This study conducted two summertime field observations in 2013 and 2021 at a background site of North China to comprehensively explore the regional variations in concentration, nitrogen isotope composition (δ15N), and sources of ammonium (NH4+). The results indicate that NHx (NHx = NH3 + NH4+) concentration has increased in 2021, but the fNH4+ (NH4+/ NHx) has decreased significantly. The δ15N-NH4+ values show a significant increase, ranging from −4.7 ± 8.1 ‰ to +12.0 ± 2.4 ‰. The increase can be attributed to two primary factors: changes in fNH4+ resulting from the reduction of atmospheric acid gases and alterations in the sources of NH3. Bayesian simulation analysis reveals substantial variations in NH3 sources between 2013 and 2021 observations. Non-agricultural sources have significantly increased their contribution to NHx concentration, with vehicle exhaust and NH3 slip experiencing growth rates of 187 % and 104 %, respectively. Our results confirm the dominate contribution of non-agricultural sources to regional NH3 at the present stage and propose relevant mitigation strategies, which would provide essential insights for reducing NH3 emissions in North China.

Climate and energy targets under Europe 2020 strategy and their fulfillment by member states

European member states have taken several systematic steps on the way to become low-carbon and resource-efficient economies since the adoption of the Europe 2020 Strategy. The long-term targets in the field of climate and energy challenges is currently being continued and developed through the sustainable development goals (SDGs) of the 2030 Agenda. In order to assess the current situation and progress in the given area, it is necessary to consistently analyze the results that the member states have achieved during the validity of the Europe 2020 Strategy. Therefore, the aim of the article is to analyze and assess the degree of fulfilment of Europe 2020 targets by EU member states in the field of the environment with a subsequent link to the targets of the 2030 Agenda. We compared the values of the selected indicators (Share of renewable energy in gross final energy consumption (RER), Final energy consumption (FEC), Primary energy consumption (PEC) and Net greenhouse gas emissions (GHG) in the EU Member States with the national goals of the selected countries by application of multivariate comparison methods, namely, the ranking method, the scoring method and the distance method. Among the countries that achieved the best results in the evaluation were Greece, Romania and Estonia. On the other hand, in the sample of countries, there were four, namely, France, Ireland, Austria and Belgium, which did not meet the targets and based on the prediction, they will not achieve them even by 2025.

High Purity Hydrogen and Carbon Dioxide Separation with Electrochemical Pump Operation of HT-PBI Fuel Cell at 120°C

A commercially available, polybenzimidazole (PBI) membrane based electrochemical hydrogen pump (EHP) platform was thoroughly evaluated to generate a benchmark set of performance. A primary gas mixture of CO2 and H2 with a ratio of 4:1 was selected to demonstrate the performance of EHPs while addressing concerns of CO2 poisoning effect. There is no indication of significant CO poisoning as a result of reverse water gas shift reaction (RWGS), and nearly Faradaic current efficiencies were successfully achieved. It was found that humidification of the feed gas at room temperature improved polarization performance while also improving energy efficiency, thus reducing the need for tightly controlled relative humidity of feed gas. A new perspective on EHP energy efficiency calculation methodology is also provided by inclusion of the cell heating requirement into the calculation. In this manner, an overall improvement to energy efficiency nearing 20% was realized by dropping the cell temperature to 120°C while paying no significant penalty to electrochemical performance. Nearly 99.99% pure H2 and 99.93% pure CO2 were produced with a hydrogen yield of 99.34%.

Development of microfluidic chip flowmeter-based constant pressure system for analysing the hydrogen adsorption performance of non-evaporable getters

BackgroundAs one of the primary residual gases in vacuum, hydrogen affects the performance of MEMS devices. It commonly uses a non-evaporable getter (NEG) to adsorb hydrogen in this case. One of the standard test methods for NEG is the constant pressure method. However, most constant pressure test systems control the intake flow by valves or small orifices. These methods are crude and limit the reliability of the result. Therefore, it is necessary to provide a stable intake flow method for the constant pressure test system to improve the accuracy of the test. ResultsWe demonstrate a constant pressure system based on the microfluidic chip flowmeter to evaluate the hydrogen adsorption performance of non-evaporable getters in this paper. The microfluidic chip features microchannels with a height of around 100 nm. It is encapsulated with standard tube fittings, with leakage of less than 1 × 10−13 Pa ∙ m3∙ s−1. The conductance of the flowmeter is 10−12 m3∙ s−1, and the upper-pressure limit of the molecular flow is 105 Pa. It can control the intake flow of the adapted constant pressure test system from 10−11 to 10−7 Pa ∙ m3∙ s−1. Using this system, we tested the hydrogen adsorption capability of the Zr–Fe getter at different working pressures/temperatures and the types of gas it adsorbs were analysed. The results showed that the adsorbent has a noticeable adsorption effect on H2 and a partial adsorption effect on H2O, CO and CO2. SignificanceThe microfluidic chip flowmeter can provide a stable intake molecular flow for the adapted constant pressure test system. It ensures the reliability of the measurement results. The ability of the flowmeter to offer tiny flow rates at 105 Pa can drastically simplify the test system and is more user-friendly for getters tests with poor adsorption performance. It has positive significance for industrial research on the non-evaporable getter.

Microwave assisted pyrolysis of biomass feedstock fundamentals and the effect of process parameters - A Review

Globally, biomass usage as a supply of non-depletable resources materials used in the production of energy at their rawest state is an issue. Pyrolysis is a method of thermally treating biomass that as a consequence in the formation of liquid, products, both solid and gaseous. Elevated heating is required to transform the complicated composition of the biomass’s underlying structure matrix into usable products. Heating with a microwave oven has the potential to become a competitive option. to more traditional methods of heating. Owing to its ease of operation and rapid heating rate, it has recently been widely employed in pyrolysis. The goals of this research are to found the principles of MW-assisted pyrolysis action and to examine some critical issues characteristics of operation that have an influence on the yield of a product. This procedure appears to be governed by a number of operational factors for instance, microwave power and temperature degree, the addition of microwave absorbers and their concentration, initial relative humidity, primary sweep gas flow rate/time spent in residence.

Ordovician reservoirs in Fuxian area: Gas accumulation patterns and their implications for the exploration of lower Paleozoic carbonates in the southern Ordos Basin

In recent years, the Fuxian area in the southeastern Ordos Basin has undergone significant exploration, with industrial gas flow tested in wells drilled into the Ordovician marine carbonates. Despite this, the gas accumulation patterns of this area are not fully understood, posing challenges for further exploration. Our analysis of geological conditions indicates that the Ordovician Majiagou Formation in this area hosts two gas plays: one found in weathering crusts and the other found in interior of the formation. We investigated various typical gas reservoirs in the area, focusing on differentiating the geological conditions and factors controlling gas accumulation in the weathering-crust and interior gas reservoirs. The results suggest three primary gas accumulation patterns in the Majiagou Formation in the Fuxian area: (1) upper gas accumulation in weathering crusts, present in the high parts of landforms such as residual paleo-hills or buried paleo-platform (Pattern I); (2) the stereoscopic pattern with gas accumulation in both weathering crusts and strata interior, arising in high parts of landforms such as residual paleo-hills or buried paleo-platforms (Pattern II); (3) lower gas accumulation in strata interior, occurring in the upper reaches and on both sides of paleo-trenches (Pattern III). This study will serve as a geological basis for future exploration deployment in the Fuxian area.

Development of a Bamboo Toothbrush Handle Machine with a Human–Machine Interactive Interface for Optimizing Process Conditions

Non-renewable materials like plastics are widely applied on toothbrush handles and bristles. Polypropylene (PP) or polyethylene (PE) is often used to fabricate the toothbrush handle, while nylon (PA) is used to form the bristle. These plastics are sourced from non-renewable fossil fuels. The primary greenhouse gases—nitrous oxide (N2O) and carbon dioxide (CO2)—in the Earth’s atmosphere are released during the production of these plastics. Bamboo can generate 30% more oxygen than most plants and trees, which absorbs twice as much carbon dioxide as trees. A comparison of the cradle-to-grave material requirements between bamboo and plastic toothbrushes reveals that bamboo toothbrushes entail hidden environmental costs. Nevertheless, bamboo toothbrushes can be completely decomposed in the environment, which makes them eco-friendly and sustainable green products. This research aims to develop a bamboo toothbrush handle machine with a human–machine interactive interface and production management for optimizing process conditions. The machine is designed as a double-group to stably mass-produce high-quality bamboo toothbrush handles under optimal process conditions. Although bamboo is a sustainable green material, the shaping process is difficult due to an extremely anisotropic property in the bamboo structures. An improper process condition will induce a rough or scorched surface, which may further cause a tearing crack. The bamboo toothbrush handle milling machine is usually designed by a profiler, which uses various molds to change the shapes and sizes of bamboo toothbrush handles. This machine cannot probe the accurate cutting force for optimizing the cutting operations, paths, and parameters. The proposed equipment with a double-group design includes two storage racks of raw materials, two feeding devices, two exchange clamping devices, and a dual-spindle milling system required to form the shaping process of bamboo toothbrush handles. The whole system is propelled by a computer numerical control (CNC) SYNTEC controller, which can fabricate the bamboo toothbrush handle with various shapes and dimensions. This controller is integrated with a LabVIEW human–machine interactive interface via a Modbus RTU communication protocol. The optimal milling paths, manufacturing methods, and feeding rates are verified by a surveillance system to detect the instant currents of both spindles via the trial-and-error method and mass production. The maximum output of the equipment can reach four bamboo toothbrush handles per minute and 1600 bamboo toothbrush handles per day.

Tri-generation for sustainable poultry litter valorization: Process design, simulation, optimization, and sustainability assessment for waste-to-wealth

A tri-generation-based sustainable poultry litter (PL) valorization process has been developed in this study. To make the proposed process economically viable and energy efficient, the primary gasification process of PL is further enhanced to convert syngas into dimethyl ether (DME). According to our energy analysis, the current tri-generation process exhibits 57% energy efficiency, which is 12% higher than that of PL gasification (45%). A particle swarm optimization (PSO)-based algorithm was applied to optimize the gasification and DME production process. According to PSO results, the optimum operating conditions are 667 °C, 2 bar, and 1.78 air ratio in the gasification process, while using reaction temperatures of 400 and 100 °C in the DME reactors leads to 242.6 kg/ton DME with 4414.6 kJ/s net heat. On the contrary, only 190.8 kg/ton DME with 4642.2 kJ/s net heat can be generated in the base process. The optimized process is economically viable to achieve an 80% plant operational efficiency with an internal rate of return (IRR) of 16.3% when compared with the base process, which becomes infeasible when the plant efficiency is <90%. A sustainability index (SI) was developed, and the results show that the optimized process was more sustainable (0.290) than the base process (0.279). Therefore, our optimized DME process is more economically viable and eco-friendly.

Comprehensive analysis of gas production for commercial LiFePO4 batteries during overcharge-thermal runaway

The failure and fires have increasingly become puzzles that may not be ignored for Li-ion batteries (LIBs). Overcharging is notoriously difficult to detect in the early stage. To address this problem, eight types of commercial LiFePO4 batteries are used to evaluate overcharge-thermal runaway (TR) properties in a sealed chamber, including surface temperature, voltage, pressure, and vent gas. And a gas-based fault diagnosis method is proposed based on the gas results. The results show that the Tmax and Pmax of the cells are between 121–150 °C and 132–144 kPa except for the battery type 3. The primary gases measured by the gas chromatograph are CO, H2, CO2, and alkanes, and the total amount of gases ranges from 12 to 45 mmol. Moreover, the proportions of H2 and CO2 both exceeded 30 %. Furthermore, the overcharge-warning experiment showed that H2 was outperformed by CO and CH4, and the capture time was 271 s and 579 s earlier than smoke and TR. Once the gases are detected, TR may be completely suppressed, and the battery neither smokes nor fires. The gas-based TR method is significantly superior to the traditional method in terms of reliability and rapidity. This study can provide a reference for the fault diagnosis of LIBs.

Carbon Capture Using Porous Silica Materials.

As the primary greenhouse gas, CO2 emission has noticeably increased over the past decades resulting in global warming and climate change. Surprisingly, anthropogenic activities have increased atmospheric CO2 by 50% in less than 200 years, causing more frequent and severe rainfall, snowstorms, flash floods, droughts, heat waves, and rising sea levels in recent times. Hence, reducing the excess CO2 in the atmosphere is imperative to keep the global average temperature rise below 2 °C. Among many CO2 mitigation approaches, CO2 capture using porous materials is considered one of the most promising technologies. Porous solid materials such as carbons, silica, zeolites, hollow fibers, and alumina have been widely investigated in CO2 capture technologies. Interestingly, porous silica-based materials have recently emerged as excellent candidates for CO2 capture technologies due to their unique properties, including high surface area, pore volume, easy surface functionalization, excellent thermal, and mechanical stability, and low cost. Therefore, this review comprehensively covers major CO2 capture processes and their pros and cons, selecting a suitable sorbent, use of liquid amines, and highlights the recent progress of various porous silica materials, including amine-functionalized silica, their reaction mechanisms and synthesis processes. Moreover, CO2 adsorption capacities, gas selectivity, reusability, current challenges, and future directions of porous silica materials have also been discussed.

Experimental and numerical study on gas production decline trend under ultralong-production-cycle from shale gas wells

It is of engineering interest to explore recovered shale gas composition and its effects on total gas production trend over a long-term extraction period. However, there are previous experimental studies mostly focused on short term development for small scaled cores, which is less convincing to mimic reservoir-scaled shale production process. In addition, the previous production models mostly failed to account for comprehensive gas nonlinear effects. As a result, in this paper, to illustrate the full-life-cycle production decline phenomenon for shale gas reservoir, dynamic physical simulation was performed for more than 3433 days to simulate shale gas transport out of the formations over a relatively long production period. Moreover, a five-region seepage mathematical model was then developed and was subsequently validated by the experimental results and shale well production data. Our findings show that for physical simulation, both the pressure and production declined steadily at an annual rate of less than 5%, and 67% of the total gas in the core was recovered. These test data supported earlier finding that shale gas is of low flow ability and slow pressure decline in the shale matrices. The production model indicated that free gas accounts for the majority of recovered shale gas at the initial stage. Based on a shale gas well example, free gas extraction makes up 90% of produced total gas. The adsorbed gas constitutes a primary gas source during the later stage. Adsorbed gas contributes more than 50% of the gas produced in the seventh year. The 20-year-cumulative adsorbed gas makes up 21% of the EUR for a single shale gas well. The results of this study can provide a reference for optimizing production systems and adjusting development techniques for shale gas wells throughout the combinations of mathematical modeling and experimental approaches.

Impurity Analysis of 5.5 N Nitrogen Gas and Its Impact on the Preparation of Class I Type Calibration Gas Mixtures

AbstractKnowledge of impurities in matrix gas is one of the critical requirements for the preparation of class I type calibration gas mixtures (primary reference gas mixtures, PRGMs) as per ISO 6142‐1. PRGMs are prepared gravimetrically using high‐purity component gas and high‐grade nitrogen, here 99.9995 % (5.5 N) as matrix gas. In this study, quantification of gaseous impurities such as moisture (H2O), methane (CH4), and carbon monoxide (CO) in 5.5 N nitrogen is performed using CRDS (cavity ring down spectroscopy). Carbon dioxide (CO2) and total hydrocarbons (THC) are analyzed using gas chromatography flame ionization detector (GC‐FID), while the determination of nitrogen dioxide (NO2) impurity is conducted colorimetrically using a UV‐Vis spectrophotometer. Total impurities in 5.5 N nitrogen are found to be (2945±21.5) ppb. The impact of utilizing this nitrogen is examined through the stability study of ambient range binary component gas mixtures of CH4 and CO in nitrogen and found that 5.5 N nitrogen can be used as matrix gas for preparing PRGMs of CH4 and CO. However, the component gas impurity present in nitrogen potentially affect the accuracy of gravimetrically prepared gas mixture.

A rapid approach to evaluating ground surface conditions for shale gas extraction in mountainous areas

Ground surface conditions, regarding the engineering, eco-environmental, and economic constraints, are crucial for shale gas extraction in the mountainous areas. A novel approach has thus been proposed to perform a rapid and integrated evaluation of ground surface conditions on a regional scale. The southeastern margin of the Sichuan Basin, China’s primary shale gas exploitation target, serves as an example to demonstrate the execution of this approach. Critical metrics for ground surface condition evaluation, including geomorphology, land utilization, water supply, and transportation conditions, were obtained from published GIS and remote sensing data. Different ratings were assigned to facilitate a quantitative evaluation of the metrics, and the composite index was calculated based on the ratings. The study area was first filtered using a composite index threshold determined from the calculated values at the existing well sites. The contiguous regions with the sufficient dimensions within the screened area were further selected as the final potential targets. The overall assessment recommended that only 10.99%, 7.61%, and 4.86% of the study area be deemed marginally, moderately, and highly suitable for potential shale gas extraction sites, respectively. These results suggest that this approach can enable efficient and accurate ground surface condition evaluations beyond the actual field surveys, while excluding the most unsuitable areas for further shale gas extraction site selection.

Ice Core Methane Analytical Techniques, Chronology and Concentration History Changes: A Review

Ice cores are invaluable in paleoclimate research, offering unique insights into the evolution of the natural environment, human activities, and Earth’s climate system. Methane (CH4) is a crucial greenhouse gas, second only to CO2 in its contribution to global warming, and is one of the primary anthropogenic greenhouse gases. Understanding historical CH4 concentration changes is essential for predicting future trends and informing climate change mitigation strategies. By analyzing gas components trapped in ice core bubbles, we can directly examine the composition of ancient atmospheres. However, there are relatively few comprehensive reviews on ice core CH4 testing techniques, chronology, and concentration history records. In response to this gap, our paper systematically reviews ice core CH4 analytical techniques, chronology, and concentration history changes. Our review indicates that current research on CH4 in non-polar ice cores is insufficient compared to polar ice cores, facing challenges such as high data dispersion, outlier frequency, and the presence of non-atmospheric signals. These limitations hinder our in-depth understanding of CH4 signals in non-polar ice cores, and the reliability of atmospheric CH4 concentration changes they reflect. To address these challenges, we propose exploring and applying advanced testing techniques, such as Continuous Flow Analysis technology, in non-polar ice cores. Additionally, we emphasize the research gap in utilizing CH4 records for age determination in ice core chronology. Future research should focus on this area to advance our understanding of ice core chronology and the history of atmospheric CH4 changes in non-polar regions, ultimately contributing to more effective climate change mitigation efforts.

Sensitivity of pollutant concentrations in urban streets to asphalt and traffic-related emissions

The higher concentrations of atmospheric particles, such as black carbon (BC) and organic matter (OM), detected in streets compared to the urban background are predominantly attributed to road traffic. The integration of this source of pollutant in air quality models nevertheless entails a high degree of uncertainty and some other sources may be missing. Through sensitivity scenarios, the impacts on pollutant concentrations of sensitivities related to traffic and road-asphalt emissions are evaluated. The 3D Eulerian model Polair3D and the street network model MUNICH are applied to simulate various scenarios and their impacts at the regional and local scales. They are coupled with the modular box model SSH-aerosol to represent formation and aging of primary and secondary gas and particles. Traffic emissions are calculated with the COPERT methodology. Using recent volatile organic compound speciations for light vehicles with more detailed information pertaining to intermediate, semi- and low-volatile organic compounds (I/S/LVOCs) leads to limited reductions of OM concentrations (10% in streets). Changing the method of estimating I/S/LVOC emissions leads to an average reduction of 60% at emission and a decrease of the OM concentrations of 27% at the local scale. An increase in 219% of BC emissions from tire wear, consistent with the uncertainties found in the literature, doubles the BC concentrations at the local scale, which remain underestimated compared to observations. I/S/LVOC emissions are several orders of magnitude higher when considering emissions from road asphalt due to pavement heating and exposure to sunlight. However, simulated concentrations of PM at the local scale remain within acceptable ranges compared to observations. These results suggest that more information is needed on I/S/LVOCs and non-exhaust sources (tire, brake and road abrasion) that impact the particle concentration. Furthermore, currently unconsidered emission sources such as road asphalt may have non-negligible impacts on pollutant concentrations in streets.

Decarbonizing the Spanish transportation sector by 2050: Design and techno-economic assessment of the hydrogen generation and supply chain

The transport sector is difficult to decarbonize due to its high reliance on fossil fuels, accounting for 37% of global end-use sectors emissions in 2021. Therefore, this work proposes an energy model to replace the Spanish vehicle fleet by hydrogen-fueled vehicles by 2050. Thus, six regions are defined according to their proximity to regasification plants, where hydrogen generation hubs are implemented. Likewise, renewables deployment is subject to their land availability. Hydrogen is transported through an overhauled primary natural gas transport network, while two distribution methods are compared for levelized cost of hydrogen minimization: gaseous pipeline vs liquid hydrogen supply in trucks. Hence, a capacity of 443.1 GW of renewables, 214 GW of electrolyzers and 3.45 TWh of hydrogen storage is required nationwide. Additionally, gaseous hydrogen distribution is on average 17% cheaper than liquid hydrogen delivery. Finally, all the regions present lower prices per km traveled than gasoline or diesel.

Development characteristics and main controlling factors of Carboniferous volcanic reservoirs in the Shixi area, Junggar Basin

The Carboniferous volcanic reservoirs in the Shixi area of the Junggar Basin are complex and diverse. Identifying the characteristics and main factors controlling high-quality volcanic reservoirs is the key to increasing oil and gas reserves and production in this area. Through core observations, thin section identification, physical property and pore structure analyses, combined with production data, the main controlling factors and development modes of high-quality reservoirs were analysed. The results show that the Carboniferous strata in the Shixi area mainly contain andesite and dacite of overflow facies, followed by volcanic breccia and tuff of explosive facies. Volcanic reservoirs in the study area are high-porosity–low-permeability and medium-porosity–low-permeability reservoirs. Volcanic breccia of explosive facies has the best physical properties, showing the characteristics of high porosity and medium permeability. The reservoir space is mainly composed of gas cavities, corrosion pores and fractures, among which the corrosion pores are the most important reservoir spaces of the Carboniferous volcanic rocks. Lithology and lithofacies, weathering and corrosion, and fractures are the main factors controlling the development of high-quality volcanic reservoirs. Volcanic rocks that had experienced weathering and denudation for a long time developed a large number of secondary corrosion pores due to the corrosion of soluble minerals or volcanic ash. Fractures further improved the physical properties, causing volcanic rocks to eventually develop into weathering crust reservoirs. The physical properties of the volcanic rocks far away from the weathering crust were improved through primary gas cavities and structural fractures, and these volcanic rocks eventually developed into the inner reservoir.