Gas Generation Research Articles

Study on the cracking process of epoxy resin under oxygen and water atmosphere based on ReaxFF force field

Amino-cured epoxy resins are widely used in the electrical and electronic industry for their excellent properties. To investigate the mechanism of the effect of O2 and H2O on the pyrolysis behavior of epoxy resin, in this paper, the cross-linked structure of bisphenol A type epoxy resin cured by adducts of diethylenetriamine and butyl glycidyl ether is modeled based on the ReaxFF force field, and the thermal decomposition processes at different temperatures and gas atmospheres were simulated and the pathways of the small molecule products were clarified. The results show that epoxy resin will produce small molecule gas products, such as H2, CO, H2O, OH, CH2O, and free radicals, in the process of pyrolysis; the presence of amino groups also generates nitrogen-containing radicals, such as CN, CH2N, and C2H4N; as the reaction temperature increases, the rate of pyrolysis reaction will be accelerated. The same temperature in oxygen and water atmospheres can accelerate the breakage of epoxy resin main chain by promoting the breakage of carbon and oxygen bonds and, at the same time, promote the generation of small molecule gases, such as H2 and CO.

The sewer advances: How to select eco-friendly pipe materials for environmental protection

Sewer pipe materials exhibit diverse inner-surface features, which can affect the attachment of biofilm and influence microbial metabolic processes. To investigate the role of the type of pipe material on the composition and metabolic capabilities of the adhering microorganisms, three sets of urban sewers (High-Density Polyethylene Pipe (HDPE), Ductile Iron Pipe (DIP), and Concrete Pipe (CP)) were constructed. Measurements of biofilm thickness and environmental factors revealed that the thickest biofilm in CP pipes reached 2000 μm, with ORP values as low as −325 mV, indicating a more suitable anaerobic microbial habitat. High-throughput sequencing showed similar relative abundances of genera related to carbon and sulfur metabolism in the DIP and CP pipes, whereas HDPE exhibited only half the relative abundance compared to that found in the other pipes. To explore the impact of pipe materials on the mechanisms of microbial response, a metagenomic approach was used to investigate the biological transformation of carbon and sulfur in wastewater. The annotations of the crucial enzyme-encoding genes related to methyl coenzyme M and sulfite reductase in DIP and CP were 50 and 110, respectively, whereas HDPE exhibited lower counts (25 and 70, respectively). This resulted in significantly lower carbon and sulfur metabolism capabilities in the HDPE biofilm than in the other two pipes. The stability of wastewater quality during the transmission process in HDPE pipes reduces the metabolic generation of toxic and harmful gases within the pipes, favoring the preservation of carbon sources for sewer systems. This study reveals the variations in carbon and sulfur metabolism in wastewater pipe systems influenced by pipe materials and provides insights for designing future sewers.

Investigation of Gas-Turbine Afterburner with Aluminized Fuel-Rich Propellant

This paper describes the design and development of a compact afterburner system for a mini gas turbine engine using aluminized fuel-rich propellant. The working principle of the system is analogous to a dual combustor ramjet engine in which the propellant is burnt in the primary chamber. Hot gases from the primary chamber combust further in the secondary chamber with incoming air from the inlet. In this work, fuel-rich gases were injected into the afterburner through radially mounted gas generators. The hot gases mix with the oxygen-rich turbine exhaust and burn further, resulting in high-enthalpy gases. These high-enthalpy gases were expanded in the convergent nozzle to generate higher exit velocity. This study investigated the thrust enhancement capability of the gas turbine afterburner system with fuel-rich propellant grains at different operating conditions. Furthermore, the effect of increasing afterburner length and decreasing nozzle exit diameter on the performance of the system was also examined. An overall static thrust of about 320 and 360 N was obtained for three and four grains, respectively, with maximum unburnt fuel residues of 11% in both the cases, out of which four grain configurations achieved a maximum thrust enhancement of around 180%.

Estimation of Boil-Off Gas Generation by using Phase-Field Model for Liquid Hydrogen Vacuum-Jacketed Valve

Estimation of Boil-Off Gas Generation by using Phase-Field Model for Liquid Hydrogen Vacuum-Jacketed Valve

Corrosion shielding effect of polyaluminium sulphate on metallic aluminium during the solidification of radioactive incineration bottom ash by low alkalinity cement

Radioactive incineration bottom ash containing metallic Al is difficult to be directly solidified in the cement matrix due to the generation of hydrogen gas during the reaction of aluminium with alkali pore solution of cement paste. In this study, the simulated incineration bottom ash (SIBA) containing metallic Al was successfully and directly solidified by polyaluminium sulphate (PAS)-modified low alkalinity cement (LAC), and the mechanism of the corrosion shielding effect of PAS on metallic Al was characterized by a range of analytical techniques. The results indicate that the cement waste form containing 29.56 wt% SIBA achieved a compressive strength of 16.6 MPa at 28 days of hydration, which increased by 13.3 % and 36.1 % after freeze-thawing test and immersion test, respectively. The 42d cumulative fraction leached of Nd3+ and Ce3+ were 1.74×10−7 cm and 3.40×10−7 cm, respectively. The corrosion degree and corrosion rate of Al sheets in LAC with PAS addition was much lower than that without PAS at early and late age hydration, by transforming thick porous corrosion layer to thin dense one. The mineral phase of corrosion product remained as bayerite (Al(OH)3), regardless of whether PAS was added. The addition of PAS reduced the hydrogen gas generation and prevented the dissolution of Al(OH)4- from metallic Al sheet. The hydrolysis of PAS produced a large amount of Al(OH)4- in pore solution, which extended the pH range for Al(OH)3 passivation by preventing the transformation of Al(OH)3 protection layer on the Al sheet surface to Al(OH)4- in the pore solution, and accelerated the formation of ettringite to decrease the pH of pore solution. This study cast the light on the direct solidification of metallic-aluminium-containing incineration bottom ash or Al bulks by cement-based materials without the need for complex pretreatment processes.

Experimental study on the mechanism of associated gas generation by heavy oil aquathermolysis and thermal cracking during steam injection

Previously, we proposed an innovative method for heavy oil recovery known as the ISSG-SAGD (in-situ solvent generation enhanced steam assisted gravity drainage) technique. This technology can improve heavy oil recovery efficiency, reduce steam consumption, and mitigate acid gas emissions. However, the reaction kinetic model used in numerical simulation was derived from literature reports and reasonable assumptions, lacking experimental validation. This study addresses this gap by conducting a series of experiments to investigate the mechanism of associated gas generation under steam injection conditions. We differentiated the reaction temperature window of aquathermolysis and thermal cracking based on the quantity and composition of the associated gas generated. The study revealed that aquathermolysis, occurring at 240–280℃, produces a small amount of associated gas (gasification degree of 0.32 %), predominantly CO2 (about 68 %). In contrast, thermal cracking, occurring at temperatures up to 380℃, significantly increases gas generation (gasification degree of 14.33 %), with light hydrocarbons (C1–5) constituting about 80 % of the gas produced. The reaction rate was found to be proportional to the reaction temperature and time. The SARA analysis showed that saturates and aromatics content increased, while resins and asphaltenes decreased after both reactions. A kinetic model for associated gas generation was established, and kinetic parameters such as activation energies and frequency factors were derived using the Arrhenius method. For example, the activation energy for CO2 generation increased from 18.19 kJ/mol during aquathermolysis to 147.58 kJ/mol during thermal cracking. This study provides a comprehensive understanding of the associated gas generation mechanisms and characteristics under steam injection, supporting the feasibility and potential application of the ISSG-SAGD technique in heavy oil recovery.

The Implications of Seeping Hydrocarbon Gases in the Gunsan Basin, Central Yellow Sea, off the Southwest of Korea

A detailed analysis of high-resolution (3.5 kHz) chirp seismic profiles acquired in the Gunsan Basin of the central Yellow Sea revealed that hydrocarbon gases are actively seeping via the formation of many plumes. The uppermost sedimentary layer was acoustically confirmed to be fully or partially charged with gases. Somewhat favored by the low-tide period, episodic gas seepage is mainly associated with the underlying fault systems of Cretaceous-Cenozoic sedimentary strata in the southwestern part of the basin. Catastrophic gas expulsion seems to have formed a crater at the sidewall of a sedimentary ridge and two diapirs. Here, methane is poorly concentrated but rich in the heavy carbon isotope (δ13C, −52.6‰ to −44.7‰ The Vienna Peedee Belemnite [VPDB]), indicating that methane formed mainly through biodegradation of heavy oils at depth remains in the shallow sediments following its expulsion. Episodic rapid upward advection of porewater is also manifest by unmixed heavy methane trapped in the upper part of the primary biogenic methane (δ13C, about −90‰ VPDB)-filled sediment core. These findings imply that the Gunsan Basin fulfills the requirements for possible generation and preservation of oil and gas, like the petroliferous basins of eastern China and the Yellow Sea.

Investigations of thermochemical fluids as cleanup system for polymer-based fracturing fluids

The cleanup of fracturing fluids, involving polymer degradation and well flowback, is crucial for the success of the fracturing operations and revenue generation. Breakers, such as oxidizers and enzymes, are commonly employed to break down polymers, resulting in lower viscosity, improved flowback, and facilitated well cleanup. However, these conventional breakers, which contribute solely to the cleanup process through polymer degradation, have some drawbacks, such as premature breaking and insufficient release of breakers. In this study, thermochemical fluids (TCFs) are proposed as a cleanup system. This system can improve the cleanup process by lowering viscosity through temperature increase and thermal degradation of polymers, reducing hydrostatic pressure via gas generation, and eliminating phase trapping damage in tight reservoirs through the heat produced. The TCFs investigated in this study were NH4Cl and NaNO2 solutions, where a substantial amount of heat was determined from the thermal energy study using an autoclave reactor. In this study, the thermal degradation of guar gum (GG) polymer derivatives, hydroxypropyl guar gum (HPG), and carboxymethyl hydroxypropyl guar gum (CMHPG) were assessed using Fourier Transform Infrared Spectroscopy (FTIR), Thermal Gravimetric Analysis (TGA), viscosity measurements, and coreflood experiments. Both FTIR and TGA analyses of linear gels of GG and its derivatives confirmed alterations in the chemical and thermal properties of these polymers following thermal treatments. The coreflood results showed a regained permeability of 87% for thermally treated HPG borate-crosslinked, 96% for CMHPG dual crosslinked (borate and zirconate), and 90% for slickwater fracturing fluids, respectively. The regained permeability of thermally treated slickwater was even better than that for slickwater with ammonium persulfate breaker.

Numerical and experimental study of energy absorption in multilayer tubes manufactured through spinning forming process under quasi-static axial loading

Currently, dual-layer tubes play a pivotal role in sectors like nuclear, oil, gas, and steam generation. Recent research focuses on enhancing energy absorption in these tubes using the spinning forming process. This thin-walled nature benefits their application as efficient energy absorbers in transportation like trains and aircraft. A novel approach integrates coarse and fine-threaded ridges between steel and aluminum layers to create a mechanical interlock using the spinning forming technique. This interlock enhances the bond through flow forming, resulting in robust dual-layer tubes. Interlayer connection strength is rigorously tested through shear tests, pre and post flow forming, indicating a significant post-flow forming enhancement. This process substantially bolsters the overall structural integrity of dual-layer tubes. In crush tests, both single-layer and dual-layer steel and aluminum tubes undergo pressing through flow forming. Comparative analysis of energy absorption parameters—specific energy and crushing percentage—reveals notable performance differences. An annealed version of the tube with an aluminum layer is also included due to prior aluminum layer failures. Among dual-layer samples, the flow formed variant with fine-threaded ribs exhibits superior energy absorption and bonding. Finite element simulation of the pressed dual-layer sample demonstrates an 8.42 % deviation between simulated and experimental energy absorption outcomes. The study highlights that tightly bonded layers result in enhanced bonding characteristics.

From 30- to 5-minute settlement rule in the NEM: An early evaluation

Australia’s National Electricity Market has shifted from 30- to 5-minute settlement (5MS)— a major regulatory reform since its inception. Using a Bayesian structural time-series model over the period 1 October 2021 to 31 May 2022, we demonstrate that despite having no immediate impact on price dynamics, 5MS eventually exerts upward pressure on spot prices over time. Price volatility remains essentially unchanged. Moreover, dispatch-weighted prices (DWPs) for flexible battery generators increase. DWPs for aggregated gas generators barely change, while DWPs for incumbent black coal-fired generators unexpectedly increase. These findings support the notion that the market is gradually adapting to 5MS. For a more effective adaptation, energy policies must be in place to lower entry barriers for flexible, dispatchable generation capacity and reduce market concentrations.

Exploring the prospects of deep natural gas resources from the geochemical parameters of the Shahejie Formation source rocks in the Banqiao depression

Deep natural gas is an important field and direction for oil and gas exploration and development in the Banqiao depression. The geochemical characteristics of the Paleogene Shahejie Formation source rocks in the Banqiao Sag were investigated based on pyrolysis, Total Organic Carbon (TOC), chloroform bitumen A, vitrinite reflectance, saturated hydrocarbon gas chromatography–mass spectrometry, and maceral determination. The results showed that the Es3 source rocks of the Paleogene Shahejie Formation were generally of better quality than the Es1 source rocks. Regarding the Es1 source rocks, the abundance of organic matter was variable, with mixed types and low maturity. The source rocks were formed in a saline-water reductive environment. Regarding the Es3 source rocks, the abundance of organic matter was relatively high, meaning that they were of medium–high quality, with mixed types of, yet highly mature, organic matter. The hydrocarbon generation environment was oxidative, and the source rocks were mainly deposited in fresh water with localized salinization. The main hydrocarbon-generating components of organic matter in the Shahejie Formation were amorphous humic components formed by intensive microbial modification of lower planktonic algae and terrestrial higher plants. Aquatic organisms were the main sources of organic matter, with localized mixing of higher-plant organic matter. The organic matter derived from these higher plant debris sources provided beneficial conditions for the generation of natural gas. At present, the Shasan source rock is at the peak of hydrocarbon generation. Under deep conditions, the maturity of organic matter increases, and organic matter rich in terrestrial higher plants can make a significant contribution to the generation of natural gas, especially shale gas.

Enhancing the safety and thermal stability of polyurethane filling materials in the mining industry through expanded graphite-based hydrated salts

The utilization of Polyurethane foaming materials (PUF) to seal coal fissures presents a significant challenge due to the substantial heat generated during the reaction process, potentially accelerating fires. In order to study this issue, we propose a novel low-heat polymerization mechanism by incorporating a hydrated salt phase change composite that efficiently absorbs polymerization heat while encapsulating liquid water using expanded graphite (EG). Our findings demonstrate that integrating 10 % EG-6 leak-free phase change material effectively reduces the reaction temperature to a safer 91.4 °C, ensuring minimal impact on the inherent properties of the material. Thorough analyses via TGA and in-situ IR experiments reveal a noteworthy 17 °C elevation in the modified PUF's thermodynamic characteristic temperature point. Additionally, we developed a mixed combustion model of PUF and coal to investigate the gas generation pattern of polyurethane in the mine-filled state where fire occurs. Specifically, the introduction of PUF reduced O2 consumption and CO production while increasing CO2 and C2H4 production, which is consistent with the reality of increased carbon hydrocarbon gases being monitored downhole. These findings suggest a synergistic, mutually beneficial relationship between the two during the low-temperature oxidation stage. This research offers perspectives for the development of polymer materials for coal mines and the safe application of actual filling.

Thermally induced release and generation of CO2 and C1–C4 hydrocarbons in Opalinus Clay from Mont Terri (Switzerland)

Claystone formations are candidate host rocks for high-level heat-emitting nuclear waste (HLW). Temperatures from 90 to 150 °C at the canister surface are discussed internationally as potential emplacement and storage conditions. The thermal energy emitted from waste containers will be transported into the host rock formation, accelerating chemical reactions including the release of sorbed and dissolved gases and the generation of new gases. This study investigated gas release and generation in Opalinus Clay from Mont Terri (Switzerland) at elevated temperature and pressure conditions relevant for HLW storage and beyond. Hydrous pyrolysis experiments were conducted in Dickson-type flexible gold-titanium reaction cells and gold capsules in the temperature range of 80–345 °C and at 20 MPa. CO2(g) was the predominant product, followed by C1–C4 hydrocarbons, which decrease in abundance with increasing carbon atom number. Neither CO nor H2S was detected. H2 was generated only in high temperature experiments at 315 °C and 345 °C, respectively. A combination of CO2(g) quantification, stable carbon isotopic composition data, thermodynamic calculations and aqueous fluid composition (dissolved ions, pH) demonstrated that ≥80 % of the measured CO2(g) originated from carbonate mineral dissolution. The model calculations also suggest that the fraction of CO2(aq) in DIC increases from ∼50 % at 80 °C to nearly 100 % at higher temperatures. Thermal transformation of organic matter represented an additional source for CO2(g) and was the predominant process yielding the C1–C4 hydrocarbons. Our findings stress the importance of quantitative geochemical data for the safety assessment of potential host rocks for HLW storage. We demonstrated that two sources are involved in gas release and generation at temperatures relevant for HLW storage, e.g., in the Opalinus Clay – organic matter and carbonate minerals. Our data will contribute to numerical modelling studies and the refinement of feature, events, and processes (FEP) catalogues.

Solvation structure and electron isolation synergy of piperidine ionic liquid additives inspires high performance lithium metal batteries

The safety concerns associated with lithium metal stand as the foremost barrier preventing widespread application of lithium metal batteries, especially due to lithium dendrite growth and gas evolution from electrolyte decomposition. This study employed N‑butyl‑N-methyl-piperidinium bis(trifluoro-methyl-sulfonyl) imide (PP14TFSI) as an additive in the electrolyte, aimed at improving the safety attributes of lithium metal batteries. The assessment conducted on the protective mechanism of the PP14TFSI additive unveiled its capability to control create robust and rapidly ion-conductive SEI by adjusting the solvation structure. Simultaneously, PP14+ intercepts free electrons, inhibiting the decomposition of DME and subsequent gas generation. Due to the synergistic effects of these two mechanisms, the rate of gas generation was reduced by half. A comprehensive investigation of lithium metal-based cells exhibited promising performance, maintaining stable cycling for 2160 h at 25 °C, 0.5 mA cm−2, displaying consistently high CE > 98.5 % in a Li||Cu cell. Moreover, at 60 °C, 2 mA cm−2, the cells maintaining stability for 240 cycles while still exhibiting relatively high CE > 98.5 %. In addition, at a low N/P ratio of 4:1, the Li-S battery maintains a high capacity of 673.4 mA h g−1 after 200 cycles, while the Li-LFP battery maintains a capacity of 131.16 mA h g−1 and capacity retention of 91.02 % after 300 cycles at 1 C. This research lays groundwork for the exploration of ionic liquids as additives in lithium metal battery electrolytes to further enhance battery safety performance.

Evaluation of municipal solid waste characterization and landfill gas power plant electrical energy production efficiency during COVID-19 pandemic

Due to the COVID-19 pandemic, the amount and types of municipal solid waste (MSW) have dramatically changed. This study focuses on characterizing the MSWs in the regular waste storage facility (RWSF) in Izmir, Turkey, and determining the electrical energy that can be produced by the landfill gas power plant (LFGPP) established to convert the waste to energy (WtE). Therefore, firstly the MSWs were characterized. After, the amount of produced methane (CH4) gas was determined using Landfill Gas Emissions Modeling (LandGEM). The amount of generated electricity, the dependent variable in the LandGEM model, was most influenced by the quantity of MSW, garbage disposal processes, and maintenance times of gas generators, while other factors remained relatively weak. This situation has also been confirmed in the field. During the COVID-19 pandemic, the increase in MSW was 9.8% in 2020 and 10.3% in 2021. Kitchen waste containing the highest CH4, accounted for 38% of the MSW characterization. The amount of generated electricity in the LandGEM model was 237 GWh in 2020 and 245 GWh in 2021. While these values could be achieved by 11.25% in 2020 due to various system and field failures, they reached 79.73% in 2021 due to system and field improvements.

New Evidences of Fluid Inclusions from Wufeng Formation Reveal Shale Gas Accumulation and Leakage Histories in Northern Guizhou, Southwestern China

Abstract Shale gas accumulation and leakage histories are significant for evaluating the prospects of hydrocarbon exploration. The Wufeng Formation in northern Guizhou is a potential target for shale gas exploration and development. This work selected a typical Well YH1 to conduct detailed fluid inclusion analyses in the Wufeng Formation. We integrated the inclusion results with systematic core description, thin-section microscopic observation, laser Raman spectroscopy, microscopic temperature measurement, and burial–thermal history to reveal shale gas accumulation and leakage histories in northern Guizhou. The results show that the source rocks of the Wufeng Formation occurred in oil generation since the Permian and entered the stage of natural gas generation at the end of the Late Triassic. During the Early Jurassic and Early Cretaceous, shale gas accumulated in the Wufeng Formation reservoirs, and the stratigraphical pressure coefficient ranged from 1.47 to 1.97. Under the influence of the Yanshan orogeny, northern Guizhou experienced a rapid uplift and exhumation since the end of the Early Cretaceous. Under the influence of this tectonic, the stratigraphical pressure plummeted to the normal level, adversely impacting the accumulated shale gas in reservoirs and resulting in leakage events since the end of the Early Cretaceous. The reservoirs were further destroyed and adjusted, and the gas continued to leak because of a long-term and large-scale uplift and exhumation during the Himalayan orogeny. This work clarified that shale gas accumulation and leakage histories are significant for evaluating petroleum exploration.

Geological Conditions of Shale Gas Accumulation in Coal Measures

The shale of different potential layers is studied by using rock pyrolysis analysis, total organic carbon determination (TOC), kerogen microscopic component identification, mineral X-ray diffraction, scanning electron microscopy, and low-temperature nitrogen adsorption experiments. The results are as follows: (1) Shishui Formation of the Lower Carboniferous and Longtan Formation of the Upper Permian are the two most important shale gas reservoirs in the Chenlei Depression. The sedimentary environment of the target shale is a marine land interaction facies coastal bay lagoon swamp sedimentary system. Two sedimentary facies of tidal flat facies, subtidal zone, and lagoon swamp facies are developed. (2) The organic matter types of shale are Type III and II2, with TOC content greater than 1%. The maturity of shale samples is relatively higher (Ro,max is above 2%), which means they have entered the stage of large-scale gas generation. The overall brittle mineral content of the target shale sample is relatively higher (above 40%), which is conducive to artificial fracturing and fracture formation in the later stage, while an appropriate amount of clay minerals (generally stable at 40%) is conducive to gas adsorption. (3) The overall pore structure of the water measurement group and Longtan group is good, with a higher specific surface area and total pore volume (average specific surface area is 12.21 and 8.36 m2/g, respectively), which is conducive to the occurrence of shale gas and has good adsorption and storage potential. The gas content of the water measurement group and the Longtan Formation varies from 0.42 to 5 cm3/g, with an average of 2.1 cm3/g. It indicates that the water measurement group and the Longtan Formation shale gas in the study area have good resource potential.

Synergizing compressed air energy storage and liquefied natural gas regasification in a power-to-biofuels plant

The present study is dedicated to the thermodynamic evaluation of an innovative system for the generation of biomethanol and natural gas, utilizing the processes of biomass gasification and high-temperature electrolysis. The recovery of waste heat from a compressed air energy storage (CAES) system serves as a crucial thermal energy source. Recognizing the periodic nature of CAES operations, a thermal energy storage (TES) system has been used to ensure a consistent supply of heat to the biomethanol production facility. The liquefied natural gas (LNG) regasification unit and an open Brayton cycle play a dual role, contributing not only to power generation and natural gas production but also to enhancing biomethanol production through the utilization of flue gases. The results of a thermodynamic modeling conducted within the Aspen Plus program demonstrate the production of 69251 ton/year of natural gas, 1424 ton/year of biomethanol, with a CO2 consumption of 3452 ton/year, resulting in an impressive overall energy efficiency of 95.27 %. The electrolyzer exhibits the highest power consumption at 1035 kW. Sensitivity analysis showed that net input electricity increases with an enhanced number of solid oxide electrolysis cell (SOEC) cells, while biomethanol capacity rises due to enhanced electrolysis size and hydrogen production rate.

Scientific-Practical Enhancement Principles for the Long-Term Stability of Cultural Heritage Objects through a Multi-Component Underground Space Analysis

This article presents approaches for enhancing engineering-geological and geotechnical research for the restoration and reconstruction projects of cultural heritage objects in St. Petersburg’s historical center. According to the Venice Charter, an interdisciplinary approach is recommended for developing a preservation program for cultural heritage objects. The authors consider the underground space as a multi-component system, where soils are a host medium for underground water with specific composition, complex physicochemical and biochemical conditions, the presence and vigorous activity of microorganisms, gases of various origins, and underground bearing and enclosing structures. The last of these components is crucial for the long-term stability of historical and cultural objects, as they interact in complex with water-saturated soils and microorganisms. This approach is not to be found in Russian cultural heritage preservation regulations. In engineering-geological and geotechnical research, multi-component underground space should be studied at the regional, local, and object levels. Assessing redox conditions in the underground environment is crucial for understanding the state of its components. Moreover, this can trigger hazardous processes such as changes in the stress–strain state and unconsolidation of the soil layer due to the generation of low-solubility gases and biocorrosion of ancient and modern building materials, causing premature destruction. Recommendations are provided for carrying out engineering-geological and geotechnical research based on cultural heritage objects, considering the multi-component underground space and features of its geoenvironmental state due to the long-term contamination and transformation of its components.

Iron-sandstone synergy: Advancing in-situ hydrogen production from natural gas via electromagnetic heating

To address the escalating demands for decarbonization in the petroleum industry, a carbon-zero technology, known as in-situ hydrogen (H2) production via electromagnetic (EM)-assisted catalytic heating, has recently been proposed for generating and extracting clean H2 directly from petroleum reservoirs. Although preliminary techno-economic analyses show significant potential of this emerging technology for clean and affordable hydrogen, the fundamentals of natural gas conversion to H2 in the presence of reservoir rocks are poorly understood. In this study, we explore the synergy between sandstone and artificial iron-based catalysts in enhancing in-situ H2 production from methane (CH4) cracking under EM irradiation. The dynamic behaviors of sandstone under EM heating are comprehensively investigated, including its thermal behaviors, thermal runaway (TR) phenomenon, gas generation during TR, and energy consumption. We found that sandstone demonstrates an evident natural catalytic effect for promoting CH4 conversion to H2, enabling H2 production starting at about 394 °C. The natural catalytic role of iron minerals in sandstone is elucidated using various advanced characterization techniques. Remarkably, when adding iron catalysts into the sandstone, the highest H2 concentration and CH4 conversion reaches 91 mol.% and 80%, respectively, at a temperature of 666 °C, while they are 50 mol.% and 35%, respectively, for the sample consisting of iron catalysts and quartz at the same level of temperature. This result indicates a strong iron-sandstone synergy and a potential to stimulate H2 production by leveraging this synergy. Throughout the experimental process, the generation of carbon oxides (CO and CO2) is negligible. These findings pave a pathway towards future pilot for carbon-zero in-situ H2 production from sandstone gas reservoirs.