Metal Loss Research Articles

A novel neural network-based framework to estimate oil and gas pipelines life with missing input parameters

Dry gas pipelines can encounter various operational, technical, and environmental issues, such as corrosion, leaks, spills, restrictions, and cyber threats. To address these difficulties, proactive maintenance and management and a new technological strategy are needed to increase safety, reliability, and efficiency. A novel neural network model for forecasting the life of a dry gas pipeline system and detecting the metal loss dimension class that is exposed to a harsh environment is presented in this study to handle the missing data. The proposed strategy blends the strength of deep learning techniques with industry-specific expertise. The main advantage of this study is to predict the pipeline life with a significant advantage of predicting the dimension classification of metal loss simultaneously employing a Bayesian regularization-based neural network framework when there are missing inputs in the datasets. The proposed intelligent model, trained on four pipeline datasets of a dry gas pipeline system, can predict the health condition of pipelines with high accuracy, even if there are missing parameters in the dataset. The proposed model using neural network technology generated satisfactory results in terms of numerical performance, with MSE and R2 values closer to 0 and 1, respectively. A few cases with missing input data are carried out, and the missing data is forecasted for each case. Then, a model is developed to predict the life condition of pipelines with the predicted missing input variables. The findings reveal that the model has the potential for real-world applications in the oil and gas sector for estimating the health condition of pipelines, even if there are missing input parameters. Additionally, multi-model comparative analysis and sensitivity analysis are incorporated, offering an extensive comprehension of multi-model prediction abilities and beneficial insights into the impact of various input variables on model outputs, thereby improving the interpretability and reliability of our results. The proposed framework could help business plans by lowering the chance of severe accidents and environmental harm with better safety and reliability.

Stochastic analysis of structural reliability of complex engineering systems

Purpose: The assessment of risks and prediction of reliability of complex engineering systems, in particular onshore gas pipelines subjected to external corrosion. Two methods are proposed using the structural reliability analysis.Methodology: Two strategies are considered for inspection and maintenance service of hazardous production facilities.Research findings: The model of structural reliability is proposed to estimate the metal rupture from external corrosion of the pipe section. Models are presented for its mechanical failure with respect to stochastic processes of loads and resistance.Value: The inhomogeneous Poisson point process is used to simulate the formation of new defects, and the Poisson distribution is used to simulate their growth. The first method focuses on the analysis of external corrosion of gas pipelines with metal loss and predicts rupture at a reference pipe segment, constructed with respect to average pipe rupture characteristics from the PHMSA database. The second model predicts reliability for untreated sections subject to external corrosion with metal loss.

Transformation and Detoxification of Typical Metallurgical Hazardous Waste into a Resource: A Review of the Development of Harmless Treatment and Utilization in China.

The production process of the metallurgical industry generates a significant quantity of hazardous waste. At present, the common disposal method for metallurgical hazardous waste is landfilling, which synchronously leads to the leaching of toxic elements and the loss of valuable metals. This paper presents a comprehensive review of the research progress in the harmless treatment and resource utilization of stainless steel dust/sludge (including stainless steel dust and stainless steel pickling sludge) and aluminum ash (including primary aluminum ash and secondary aluminum dross), which serve as representative hazardous wastes in ferrous metallurgy and nonferrous metallurgy, respectively. Additionally, the general steps involved in the comprehensive utilization of metallurgical hazardous waste are summarized. Finally, this paper provides a prospective analysis on the future development and research trends of comprehensive utilization for metallurgical hazardous waste, aiming to offer a basis for the future harmless, high-value, resource-based treatment of metallurgical hazardous waste and the realization of industrial applications in China.

Computational demystification of iron carbonyls formation under syngas environment

Iron pentacarbonyl (IPC) gas forms upon the reaction of carbon monoxide with Fe containing metallic surfaces under gas reforming conditions. IPC formation can sometimes reach alarming levels that cause metal loss, pipeline thinning corrosion, catalyst poisoning, and contamination of sensitive industrial equipment. In this work, we demystify using multiscale computational modeling the mechanism of Iron pentacarbonyl formation: Density functional theory (DFT) is used to explore various catalytic reactions that involve a Fe adatom reacting with adsorbed carbon monoxide. Our calculated carbonyls desorption barriers on a perfect and clean Fe surface are too high to allow the carbonyls to form then desorb at temperatures <500 K at the rates reported experimentally. Most importantly, our calculations indicate that a high CO surface coverage, in addition to the presence of Fe adatoms, favors carbonyl formation and its desorption towards the flowing gas medium. Using insights extracted from ab initio molecular dynamics simulations, we propose that the most plausible IPC formation mechanism consists of: (1) on surface reactions of adsorbed CO molecules with an Fe adatom to form iron tricarbonyl (Fe(CO)3*) molecules; (2) an adsorbate assisted movement of iron tricarbonyl on top of the CO adlayer; and (3) the interaction of iron tricarbonyl with CO molecules from the gaseous medium eventually leading to iron adatom removal as Fe(CO)5 gas.

Nitrogen-oxygen co-doped carbon@silica hollow spheres as encapsulated Pd nanoreactors for acetylene dialkoxycarbonylation

The introduction of heteroatoms into hollow carbon spheres is imperative for enhancing catalytic activity. Consequently, we investigated the utilization of nitrogen–oxygen(N/O) co-doped hollow carbon (C)/silica (SiO2) nanospheres (NxC@mSiO2), which have a large internal volume and a nano-constrained environment that limits metal aggregation and loss, making them a potential candidate. In this study, we demonstrate the synthesis of nitrogen–oxygen (N/O) co-doped hollow carbon spheres using resorcinol and formaldehyde as carbon precursors, covered with silica, and encapsulated with palladium nanoparticles (NPs) in situ. The N/O co-doping process introduced defects on the surface of the internal C structure, which acted as active sites and facilitated substrate adsorption. Subsequent treatment with hydrogen peroxide (H2O2) introduced numerous carboxyl groups onto the C structure, increasing the catalytic environment as acid auxiliaries. The carboxyl group is present in the carbon structure, as determined calculations based on by density functional theory, reduces the adsorption energy of acetylene, thereby promoting its adsorption and enrichment. Furthermore, H2O2-treatment enhanced the oxygen defects in the carbon structure, improving the dispersion of Pd NPs and defect structure. The Pd/NxC@mSiO2-H2O2 catalysts demonstrated outstanding performance in the acetylene dialkoxycarbonylation reaction, showcasing high selectivity towards 1,4-dicarboxylate (>93 %) and remarkable acetylene conversion (>92 %). Notably, the catalyst exhibited exceptional selectivity and durability throughout the reaction.

Sustainable Soft Electronics Combining Recyclable Metal Nanowire Circuits and Biodegradable Gel Film Substrates

AbstractDirect disposal of used soft electronics into the environment can cause severe pollution to the ecosystem due to the inability of most inorganic materials and synthetic polymers to biodegrade. Additionally, the loss of the noble metals that are commonly used in soft electronics leads to a waste of scarce resources. Thus, there is an urgent need to develop “green” and sustainable soft electronics based on eco‐friendly manufacturing that may be recycled or biodegraded after the devices’ end of life. Here an approach to fabricating sustainable soft electronics is demonstrated where the expensive functional materials can be recycled and the soft substrate can be biodegradable. A stretchable agarose/glycerol gel film is used as the substrate, and silver nanowires (AgNWs) are printed on the film to fabricate the soft electronic circuits. The mechanical and chemical properties of the agarose/glycerol gel films are characterized, and the functionality of the printed AgNW electrodes for electrophysiological sensors is demonstrated. The demonstration of the biodegradability of the agarose/glycerol and the recyclability of AgNWs points toward ways to develop sustainable and eco‐friendly soft electronics.

Estimation of solar receiver corrosion conditions during operation to aid in the design of receiver-corrosion lab tests

Solar power tower plants widely rely on molten nitrite salt as heat transfer fluid and storage media. However, its corrosiveness endangers several metallic components, with central receivers being one of the most compromised. Great efforts are being made to establish molten salt corrosion in different metals. Recently, the importance of the amount of salt used in these experiments has been highlighted. Yet, most tests disregard the hot-receiver-surface/salt ratio that would represent the receiver operation conditions. Commonly, larger metal surfaces are employed, accelerating molten salt thermal decomposition kinetics. Hence, this study seeks to develop basic design conditions for experimental corrosion tests to realistically mimic receiver-tube corrosion. Consequently, the high-temperature operation of two receiver designs, resembling those of Crescent Dunes and Gemasolar plants, with their tubes manufactured in HA230, is analysed. The yearly salt degradation in these plants is found to be nearly negligible due to the large salt volume stored and the relatively limited receiver surface above concerning temperatures, with the whole salt volume being exposed to it for around 20 min during a 25-year operation for large receivers. Moreover, the hot-metal-surface/solar-salt ratio ranges from 5 to 7 mm2/kg, depending on the receiver design, which should be preserved in a corrosion experiment. Metal loss is also estimated: less than 7 % of the receiver would lose at least 50 % of the initial tube thickness. Still, lower metal loss rates are expected since coefficients from static-isothermal tests were employed for the calculation, which also disregarded the metal surface/salt proportion, leading to an overestimation.

Bottom-preferred stripping mechanism towards quantified inactive metallic Zn0-dominant zinc loss in rechargeable zinc metal battery

Electrically isolated metallic Zn (Zn0) and electrochemically side reaction (ECSR), causes irreversible anode capacity loss and limited cycle life in zinc metal battery. However, the quantitative distinguishment between inactive metallic Zn0 and ECSR, their formation mechanism and correlation with anode cycling reversibility have never been disclosed, limiting further anode modification design. Here, we develop an acid-assisted continuous titration-collection-gas chromatography technique (AAC-TCGC) that accurately quantify the amount of inactive Zn0 and ECSR in anode, and discover that inactive Zn0 accounts for the majority of Zn loss, rather than the commonly-assumed electrochemically side reaction-derived ECSR-dominant Zn anode capacity loss. Detailed component of SEI (Solid Electrolyte Interface Layer) compound is also characterized, illustrating a solvent-derived zinc oxide/hydroxide-dominant SEI that facilitates vertical/inclined thin-plate Zn deposition, but salt-derived ZnF2-dominant SEI that favors horizontal platelet-shaped Zn(002) deposition. Simulation results reveal a new electric resistance-derived, bottom-preferred Zn stripping mechanism that leads to abundant inactive Zn0 formation in vertical thin-plate Zn deposition structure, but few inactive Zn0 in dumpy platelet-shaped Zn structure. Our study provides new theories and strategies on the distinguishment, formation mechanism and structure-performance relationship of inactive Zn, important for building more efficient Zn metal battery.

Braving the elements: Loss of metals from Mardi Gras beads due to handling and weathering

The largest Mardi Gras celebrations in the U.S. are found along the Gulf of Mexico coast. With increasing awareness of and concern for environmental and human health risks due to pollution from Mardi Gras celebrations, there is a need for studies to quantify potential harms. We conducted a 2—part study to determine whether use—related handling and weathering of common Mardi Gras beaded necklaces results in loss of potentially harmful metals to the environment at levels of ecological or human health concern. Our data indicate that weathering and use—related handling can cause metals to be shed from the metallic coating of beads to the environment. The quantity of metals released depended on the color of beads and type or intensity of handling. Even light handling, however, resulted in measurable release of metallic coating and comprising metals. In addition to indicating the need for personal caution, our data suggest metal forms that are most soluble in water may pose the greatest potential environmental and human health risks. Metals contamination from Mardi Gras beads and other accessories is worthy of additional study and consideration in monitoring efforts.

Integrity Assessment of an In-Service Gas Pipeline Featuring Dent Defect at a Highway Crossing

Underground pipelines are susceptible to different types of damage/flaws such as metal loss, buckling, dents, gouges, cracks, etc. during installation and operation. The structural integrity of the pipelines featuring such defects needs to be ensured for safe operation and to avoid serious hazards (fire/explosion/fatality/injury etc.). This paper discusses the integrity assessment of an actual case of an in-service gas pipeline featuring dent damage located at a highway crossing. A routine in-line inspection (ILI) of the considered pipeline showed the presence of a dent type of damage with a maximum depth of 5% spread over an area of 325 mm x 275 mm. Since the pipeline is located approximately 7.5 m below a 10-lane expressway with heavy traffic, dig verification of the dent was found to be not feasible. Level-3 integrity assessment based on API 579-1/ASME-FFS-1 2021 Fitness-For-Service standard has been performed using commercial finite element (FE) software ABAQUS/CAE. The considered pipeline is subjected to overburden pressure of soil embankment and cyclic loads such as vehicular loads (as per IRC: 6-2017) and internal pressure. The dented pipeline segment was assessed for potential failure modes i.e., protection against plastic collapse, local failure, collapse from buckling, and fatigue damage. FE analysis of the pipeline-soil system has been carried out considering the material and geometric nonlinearity, and contact interactions. The study suggests the pipeline is safe for further operation with existing dented defects. The methodology presented in this paper can act as a guide for the integrity assessment of pipelines with dent damage located at highway crossings.

Identifying Separation Potency and Relationship of Grade and Density of Copper Ore for Gravity-Based Early Coarse Gangue Rejection using Statistical Method

The mineral processing industry faces a pressing challenge of declining productivity, particularly in metal minerals production, driven by soaring operational costs, with crushing and grinding operations accounting for a substantial portion of the energy consumption. To mitigate these challenges, early gangue rejection or preconcentration is proposed as an effective solution. This approach involves the removal of non-valuable materials and the concentration of valuable minerals at the initial processing stages, leading to increased efficiency, higher ore feed grades, cost savings, and reduced environmental impact. Various methods for gangue rejection exist, with gravity-based separation and ore sorting being the predominant options. Gravity-based separation stands out for its simplicity and versatility, making it the preferred choice in many scenarios. This study introduces a novel approach for evaluating gangue rejection potential, optimizing data distribution, and generating theoretical separation potential curves that account for both grade and density criteria. These curves provide insights into material rejection, metal losses, and optimal separation points, offering valuable guidance for mineral processing operations. Additionally, the study investigates the correlation between raw ore grade and density data, highlighting a strong relationship across different size fractions. This finding suggests that gravity-based separation can effectively rely on both grade and density parameters, resolving previous disparities observed in distribution models. By shedding light on advanced gangue rejection strategies, this research contributes to improved productivity and informed decision-making in the mineral processing industry.

Bubbling resilient 3D free-standing nanoporous graphene with an encapsulated multicomponent nano-alloy for enhanced electrocatalysis.

The design and synthesis of highly durable and active electrocatalysts are crucial for improving the hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). In this work, we present a novel dealloyed nanoporous PtCuNiCoMn multicomponent alloy with ligaments/pores ranging from 2-3 nm, which is in situ encapsulated in a three-dimensional, free-standing nanoporous nanotubular graphene network featuring a pore/tube diameter of ∼200 to 300 nm. This method allows precise control over the noble metal loading and alloy composition while preventing noble metal loss throughout the preparation process. The innovative bimodal nanoporous graphene/alloy structure, coupled with an open 3D spongy morphology, and optimized surface Pt electronic structure through multicomponent interaction, significantly enhances the activity for the HER/ORR, outperforming commercial Pt/C. Moreover, this design addresses the issues of Pt nanoparticle aggregation and detachment from carbon supports that typically exist in Pt/C-type catalysts, thereby substantially improving the catalytic durability, even under intense gas bubbling conditions.

Monitoring Metal Loss Within Pipelines Using Fiber Bragg Grating Sensors Positioned on Repaired Sleeves

Monitoring Metal Loss Within Pipelines Using Fiber Bragg Grating Sensors Positioned on Repaired Sleeves

Sustainable environmental technology to reclaim copper from industrial effluent

ABSTRACT Electronic manufacturing industries use copper in highest proportion in metals due to its unique properties. But there is a gap in demand and supply of this metal to the industry due to its huge requirement and lack of its proper recycling of copper containing equipments. Also, effluent generated from these industries carries substantial amount of this metal, which get discharged, and loss of metals to the environment. Present paper discusses about valuable copper metal recovery from industrial effluent in powder form using novel process flow-sheet. At start, bio-adsorptiontechnique was used to recover copper from industrial effluent due to its advantages like low cost, feasible method showing faster kinetics. Datura root powder was found to be potential bio-adsorbent for copper recovery from effluent having 997 mg/g adsorption capacity. It follows second-order rate reaction and Freundlich adsorption isotherm with 0.9711 regression coefficient. Further, copper-enriched solution obtained from this technique was subjected to cementation process using scrap iron rods to get copper powder. This can be used to produce value added products using its ingots. This is one of the approaches towards waste to wealth creation having tremendous potential to get commercialized.

Origin of Stability and Activity Enhancements in Pt-based Oxygen Reduction Reaction Catalysts via Defect-Mediated Dopant Adsorption.

Platinum alloys are highly efficient electrocatalysts for the oxygen reduction reaction (ORR) in acidic conditions. However, these alloys are susceptible to metal loss through leaching and degradation, leading to reduced catalyst stability and activity. Recently, it has been shown that doping with oxophilic elements can significantly alleviate these problems, with a prominent example being Mo-doped Pt alloys. Here, to achieve atomic scale understanding of the exceptional activity and stability of these alloys, we present a detailed density functional theory description of the dopants' structures and impact on electrocatalyst properties. Beginning with the Mo/Pt system, we demonstrate that Mo can be stabilized in the form of low-dimensional oxyhydroxide moieties on Pt defects. The resulting structures enhance stability and activity via distinct physical processes, with the Mo moieties both directly inhibiting Pt dissolution at defects and indirectly enhancing ORR activity by generation of strain fields on surrounding Pt terraces. We then generalize these analyses to other metal dopant elements, and we demonstrate that similar low-dimensional oxyhydroxide structures control the electrocatalytic properties through an intricate interplay of the structures' acid stability, intrinsic activity for the ORR, and ability to induce ORR-promoting strain fields on Pt.

Origin of Stability and Activity Enhancements in Pt‐based Oxygen Reduction Reaction Catalysts via Defect‐Mediated Dopant Adsorption

AbstractPlatinum alloys are highly efficient electrocatalysts for the oxygen reduction reaction (ORR) in acidic conditions. However, these alloys are susceptible to metal loss through leaching and degradation, leading to reduced catalyst stability and activity. Recently, it has been shown that doping with oxophilic elements can significantly alleviate these problems, with a prominent example being Mo‐doped Pt alloys. Here, to achieve atomic scale understanding of the exceptional activity and stability of these alloys, we present a detailed density functional theory description of the dopants’ structures and impact on electrocatalyst properties. Beginning with the Mo/Pt system, we demonstrate that Mo can be stabilized in the form of low‐dimensional oxyhydroxide moieties on Pt defects. The resulting structures enhance stability and activity via distinct physical processes, with the Mo moieties both directly inhibiting Pt dissolution at defects and indirectly enhancing ORR activity by generation of strain fields on surrounding Pt terraces. We then generalize these analyses to other metal dopant elements, and we demonstrate that similar low‐dimensional oxyhydroxide structures control the electrocatalytic properties through an intricate interplay of the structures’ acid stability, intrinsic activity for the ORR, and ability to induce ORR‐promoting strain fields on Pt.

Effects of Compaction and Thermal Pre-treatments on Generation of Dross and Off-Gases in Aluminium Recycling

Organic coatings are a challenge for aluminium packaging recycling since they tend to increase the re-melting metal losses. A solution is de-coating the scrap via a thermal pre-treatment to burn-off the organics before re-melting. Due to logistic benefits, the scrap is often pressed into bales. This study evaluates the influence of compaction on the de-coating efficiency and off-gas emissions, and its consequences for dross formation and recycling metal yield. Loose chips and two types of briquettes, one loosely compacted by uniaxial pressure and the other compacted by moderated-pressure-torsion to higher densities, were heated to 550 °C while analysing the off-gas emissions using FTIR. The briquettes were subsequently re-melted into a molten heel. Re-melting coated scrap multiplied the % wt of dross by a factor of 2 or 3, depending on the compaction pre-treatment, compared to re-melting uncoated aluminium. The densest briquettes emitted less than half the CO2 and CO gases during de-coating and formed significantly more dross. Compaction to the lower densities showed no tangible effects. The effect of de-coating compacted materials or not was small (± 2% wt dross), which was attributed to carbonaceous residues remaining after the thermal treatment. In conclusion, high compactions by torsion limit the de-coating reactions, which depend on factors such as temperature and gas transport. A complete removal of the organic residues is critical for a more sustainable recycling with less dross generated.Graphical

Fe3+ and Al3+ removal by phosphate and hydroxide precipitation from synthetic NMC Li-ion battery leach solution

The removal of trivalent iron and aluminum was studied from synthetic Li-ion battery leach solution by phosphate and hydroxide precipitation (pH 2.5–4.25, t = 3 h, T = 60 °C). Phosphate precipitation exhibited both crystal nucleation initiation (pH 2 vs. pH 3) as well as complete (~ 99%) Fe and Al removal at lower pH compared to hydroxide precipitation (pH 3 vs. 3.5). The precipitation time of phosphate was shorter (40 min) than that of hydroxide precipitation (80 min). At pH 4 the loss of valuable metals (Li, Ni, Co) in the precipitate was negligible in the phosphate cake, whereas in the hydroxide process the co-precipitation was 4–5% for Li, Ni and Co. The filtration rate of phosphate precipitate was shown to be significantly faster. The presence of fluoride did not have any notable effect on phosphate precipitation, whereas in hydroxide precipitation, it potentially had a negative effect on aluminum extraction.

Properties governing the flow of solution through crushed ore for heap leaching: Part III – Low-permeability ores

Heap leaching is used extensively for the processing of low-grade copper and gold ores. If the ore has low permeability, it may lead to underperformance or even project failure. Poor permeability is caused by a high fines content, resulting in a high steady-state moisture hold-up which causes the bed to operate close to saturation. The problem of low permeability can be addressed by either desliming (removal of the fines by wet screening), or by agglomeration (binding the fines together) with a cementitious binder. Fines removal by desliming is shown to reduce the steady-state moisture hold-up, resulting in the bed operating further away from saturation and increasing the maximum solution application rate. Agglomeration with Ordinary Portland Cement modified with additives resulted in fine particles binding together as lumps or coatings onto coarser rocks. These bonds were not destroyed after prolonged exposure to dilute sulphuric acid, due to the pozzolanic properties of the additives (e.g. fly ash), which cause cementitious Ca-bonds to be substituted with more stable Al- or Mg-bonds. Agglomeration with cementitious binder was also found to reduce slumping in leach column tests. This resulted in a higher bed porosity, higher limits on the solution application rate and higher copper dissolution rates. Agglomeration with modified cement may provide a novel, cost-effective method for the treatment of low-permeability ores in acid medium (e.g. copper, uranium and nickel), since cement agglomeration has only been applied commercially in alkali medium (e.g. cyanide solutions for gold ores) to date. Desliming is less attractive due to the high losses of the target metal to the fines.

Stress Distribution of EH40 with Defects Considering Solid-State Phase Transformation

Residual stress of laser-welded marine steel EH40 was experimentally and numerically analyzed considering weld defects (collapse, hump, and unfitness) and solid-state phase transformation (SSPT). A double-cylindrical source model was used to simulate the temperature distribution. The mean prediction errors of the model without and with weld defects along the plate thickness were 9.2 and 3.5%. Based on the thermodynamics of SSPT, microstructure fractions were computed and verified by weld hardness test results. Under the effect of SSPT, residual stress changed from compressive stress to tensile stress with the increase of the distance from the weld center. Weld defects have an influence on the value of residual stress, and this effect was greater when SSPT was considered. The affected zone extended from the vicinity of weld defects to the whole weld. The variations of longitudinal residual stress (LRS) and transverse residual stress (TRS) caused by weld defects and SSPT both exceeded 150 MPa. LRS was mainly affected by the loss and increase of metal, while TRS was affected by the stress concentration caused by shape geometry changes. Thus, the influence of weld defects on TRS was greater than that on LRS. The proposed finite element model considering weld defects and SSPT can be used to accurately predict residual stress in laser welding of marine steel EH40 and provide a theoretical basis to reduce welding stress.