Industrial Piping Research Articles

Waste Reduction in Pipe Industry Through Lean Six Sigma Implementation

This research investigates to manage waste in longitudinal submerged arc welded (LSAW) steel pipes by the utilization of Lean Six Sigma (LSS) tools, with an emphasis on promoting sustainability through waste reduction. The DMAIC approach was implemented to ascertain underlying causes, enact modifications, and oversee practices. Reusing, recycling, and repurposing of materials was employed to minimize production waste. The findings demonstrate a noteworthy decrease in waste with regards to the overall weight of raw material, from 5.3% to 3.4%, and a reduction in monetary losses by 58.07%. The implementation of the LSS methodology has been shown to augment customer satisfaction, minimize waste and variation, and improve sustainability in numerous industries. The effectiveness of the LSS approach in managing waste and promoting sustainability in the LSAW sector was validated by consistent results, as evidenced by the control plan. Given the crucial significance of efficient waste management for sustainable production and consumption, this research underscores the potential of LSS as a resilient methodological approach to reduce waste and advance sustainability in the industry.

Low-Cost Material Derived from Coconut Husk for the Removal of Chromium(VI) from Water Environment

A low-cost bio-material was derived from biomass agricultural by-product (coconut husk) and applying it in water treatment, makes both economic and environmental sense. Hexavalent chromium has been confirmed to be the most hazardous oxidation state of chromium and is potentially carcinogenic; therefore, it must be removed from the industrial effluent pipe before being discharged. The presents work focus on the fabrication of biochar from coconut husk and using for removing of chromium hexanvalent from aquatic environment. The Batchwise study and a chromatographic operation were used to exame the chromium(VI) reduction/adsorption performance. The typical results indicated that the removal of chromium(VI) was achieved in acidic region via adsorption and reduction processes. The kinetic study followed pseudo-second-order model (R2 ≈ 1.0), the results revealed that biochar at 800oC (BCH-8) system was occurred 6.2 times faster than that of raw coconut husk (BCH-raw). The diffusion-chemisorption kinetic model indicated that the BCH-raw system was only adsorption, but BCH-8 was both adsorption and reduction processes at pH 3.0. The removal of chromium(VI) by biochar based coconut husk was also achieved by chromatographic operation.

Analyzing the Financial Performance of PT. Steel Pipe Industry of Indonesia Tbk

The financial report is a vital tool for acquiring insights into a company's financial position and business performance. Through financial statement analysis, crucial indicators pertaining to the company's financial health are unveiled, rendering it a valuable resource for guiding financial decision-making processes and offering a comprehensive portrayal of the company's performance. This study evaluates the financial performance of PT Steel Pipe Industry of Indonesia Tbk. and forecasts the company's sales turnover over the next five years. This research adopts a quantitative descriptive approach, utilizing secondary data spanning from 2018 to 2022 from the PT Steel Pipe Industry of Indonesia Tbk. The data analysis process encompasses several stages, including (i) Ratio Analysis of Financial Reports from 2018 to 2022, (ii) Compilation of sales data, (iii) Projections of sales figures using the least squares method, and (iv) Forecasting profits for the period from 2023 to 2027. The findings of this study indicate that the PT Steel Pipe Industry of Indonesia Tbk. is facing challenges in its financial performance, as the ratio values consistently fall below industry-standard financial metrics. However, the company has demonstrated resilience in maintaining its profitability levels, evidenced by a 6% increase in profit percentage in 2021 compared to 2020. This can be attributed to the company's consistent profit generation efforts, resulting in year-on-year profit growth.

Corrosion and Degradation Behavior Using Aluminum and Copper As Refrigerant Piping

Introduction Many types of refrigerant piping use copper alloys owing to their high workability, thermal conductivity and weatherability. However, copper is the 25th place in Clark number (relative abundance of a chemical element, typically in Earth’s crust), and have the relative low value (ca. 0.01). Therefore, there is concern about depletion, if that is consumed in large quantities via emerging country and new devices such as electric vehicle and so on. Recentry, we focused on aluminum as light metal, which is the 4th place in Clark number (ca. 7.6), and applied for refrigerant piping of air-conditioning equipments, and the practical application has been achieved in the some case. Moreover, in the case of practical use for pipework of actual equipment, long-term (more than 20 years) performance evaluation by corrosion is neccesary. Therefore, in this study, we investigated corrosion-resistant characteristic of various aluminum alloys by accelerated degradation tests with changing storage tempetature and atmosphere. In general, the corrosion factor of the piping materials depends on their contact atmosphere, and differs inside (refrigerant) and outside (e.g., air) of the piping. In concrete terms, there are concerns about the acid of refrigerant oil and salt corrosion of sea water at inside / outside of the piping. According to the usage condition of piping, we proposed immersion tests and cyclic corrosion tests such as intermittent cycles between salt mist and drying, and chemically analyzed by microscope, weight observation and corrosion potential measurements [1]. Experiments All experimental copper and aluminum samples were obtained as commercially used refrigerant piping of Japan. To evaluate the corrosion resistance of the materials in contact with the refrigerant (inside piping corrosion), immersion tests were performed in an electrolyte which was a mixture refrigerant fluid R-410A (a difluoromethane / pentafluoroethane mixture 50:50 by mass) and refrigeration machine oil (synthetic oil that consisted of polyvinyl ether, an antioxidant, and a wear-resistant agent).Immersion tests were conducted at 393K (maximum temperature for practical use) for 20 days. The appearance, sample mass, and self-electrode potential of the test samples were investigated before and after the immersion tests, as fundamental evaluations.To investigate the corrosion resistance of the materials in the field environment (outside piping condition) a cyclic degradation test was performed according to JASO M610-92. One cycle of this Japanese Automotive Standard lasts 8 hours contains 3 process steps: a tridimensionality spray of saltwater (5.0 wt.% sodium chloride, pH 6.5–7.2, 308 K) for 2 ha dry process (333 K, humidity: 25 %) for 4 ha wet process (323 K, humidity: 95 %) for 2 h The samples were removed from the testing process at specific times (8, 16, 24, 96, 192, 384, and 496 h), and were investigated in terms of appearance, mass loss and depth of pitting corrosion. Results & Discussion Immersion tests results show negligible damage to copper and aluminum alloys by chemical and thermophysical effects up to 393 K, the maximum temperature for practical use and they confirm useful piping properties for the inside of aluminum and copper alloys.Fig. 1 shows the explored time dependences of corrosion weight loss for two-types copper alloy in cyclic corrosion tests. Both logarithmic of corrosion weight loss for two copper alloy increased with the logarithmic of explored time until 496 h. The passivation film formation at copper alloy should not be occurred by the cyclic corrosion conditions for outside piping. Fig. 2 (a) shows the explored time dependences of corrosion weight loss for two-types aluminum alloy in cyclic corrosion tests. Weight loss of A6063-T83 was relatively larger than that of A3003-O. Although the corrosion weight loss of A3003-O linearly increased up to 96 h and showed stable weight passage of ca. 0.5 g m-2, that loss of A6063-T83 also linearly increased up to 96 h and exhibited stable and huge weight passage of ca. 1.5 g m-2 resulting from the difference of passivation film formations. We also observed each depth profiles of each corrosion pitch, and confirmed favorable accordance with the mass loss (Fig.2(b)). The accelerated degradation results for 496 h of cyclic corrosion tests are corresponding to 1.5 years of exposure on the Okinawa Prefecture coastline and to 20 years of exposure in Kariya city, Aichi Prefecture, an inland area. Therefore, we experimentally demonstrated the high weathering resistivity of aluminum alloy piping, which can exceed that of copper alloy. We have also demonstrated the 20 years durability of industrial piping in inland areas that do not experience salt-induced corrosion.[1] S.Uchiyama, et., al., Mater Corros.(Wiley), 74, 344-351 (2023). Figure 1

Ultrasonic inspection of sludge accumulated in plastic pipes using meta-slab mode-converting wedge transducers

Noninvasive ultrasonic inspection of sludge accumulated inside fluid-flow pipes is important to avoid a catastrophic pipeline failure. Although an earlier ultrasonic inspection method is applicable to both metal and plastic pipes, it can be applied only when the height of the accumulated sludge inside a plastic pipe is larger than about 1/5 of the pipe diameter. Considering the wide use of plastic pipes in various industries, lowering the detectable height of the accumulated sludge can be critically important. Here, we propose a non-conventional method to inspect the sludge inside a plastic pipe, the height of which can be as low as zero in theory. While the earlier method used only L (longitudinal) waves for the inspection, the proposed method uses different wave modes in different media along the wave passage from a PZT transducer to the fluid via the pipe wall. Specifically, we generate an L wave from the PZT, fully mode-convert it to an S (shear) wave before transmitting it to the wall of a plastic pipe, and convert it back to an L wave in the fluid. The suggested wave passage should ensure that the L wave in the fluid propagates horizontally or parallel to the fluid surface for accurate height estimation. We show why using the S wave in the pipe wall is critical in lowering the detectable height of the sludge; additionally, for the full-power L-to-S mode-conversion from the PZT to the pipe wall, a meta-slab mode-converting wedge is designed by a PEEK-based metamaterial. The specific wedge configuration will be also presented. Using the proposed novel sludge inspection method, we performed numerical simulations and experiments in PVC pipes in which simulated sludges of different heights were considered. Our numerical and experimental results confirm that the detectable heights of the accumulated sludge were considerably lower than those by the existing approach that does not use the S wave.

Numerical Insights from a Population Balance Model into the Distribution of Bitumen Residues in Industrial Horizontal Pipes During the Hydrotransport of Oil Sands Tailings

Numerical Insights from a Population Balance Model into the Distribution of Bitumen Residues in Industrial Horizontal Pipes During the Hydrotransport of Oil Sands Tailings

Ash fusion characteristics of iron‐rich coal in Xinjiang under different atmospheres and the influence mechanism of adding red mud and pipeline scale

AbstractTo realize the high‐efficiency utilization of iron‐rich coal, it is necessary to conduct in‐depth research on the ash fusion characteristics and regulation mechanism. In this paper, the ash fusion temperature test of iron‐rich coal in Xinjiang (ZC) under different atmospheres was first carried out. Then, red mud (HJ) from Huajin Aluminum Industry and black water pipe scale (GDG) were selected as the additives. After the same ashing procedure, the two additives were mixed with iron‐rich coal ash in different proportions to realize the regulation of the chemical composition of the coal ash to improve the ash fusion characteristic. The ash fusion temperature (AFT) experiment was carried out in the automatic ash melting point analyzer, and high‐temperature ash melting slags at different temperatures were prepared. The mineral phases of coal ash and slag were characterized by XRD and compared with the Factsage simulation calculation results to reveal the influence mechanism of coal ash fusion temperature. The result shows that the fusion temperature of ZC iron‐rich coal ash is significantly different between oxidizing atmosphere and weak reducing atmosphere. Compared with the oxidizing atmosphere, the four characteristic temperatures of ZC iron‐rich coal ash are significantly lower under weak reducing conditions, and the difference is about 150°C. The addition of red mud and pipeline scale increased the fusion temperature of ZC coal ash to varying degrees. The addition of HJ ash has little effect on the deformation temperature of ZC coal ash, while the addition of different proportions of HJ ash significantly increases the flow temperature of ZC coal ash. When the addition ratio of HJ ash is 40%, the flow temperature FT of ZC coal ash increases most obviously, which is about 50°C. The addition of HJ ash and GDG ash will lead to an increase in the content of iron‐containing spinel, thereby increasing the ash flow temperature.

Adhesive reinforced friction stir welded thermoplastic tube-to-tubesheet hybrid joints

Thermoplastic materials are gaining popularity, because of their anti-fouling and chemically inert properties, for use in industrial applications that involve heating and cooling of highly reactive fluids. The current work studies the effect of adhesive reinforcement and radial clearance (RC) on developing friction stir welding (FSW)-based thermoplastic tube-to-tubesheet hybrid joints (TTHJs), which has applications in the thermoplastic heat exchanger and piping industries. The workpieces (sheets and tubes) made of carbon black reinforced high-density polyethylene were used. First, the effect of FSW parameters on the tube pull-out behavior was studied. The fractographic investigations (macroscopic and SEM) suggest that the FSW joints can fail in a brittle, ductile, or mixed manner, depending on the FSW conditions used. The FSW technique provides better load bearing capacity (326 N (0.0 RC), 517 N (0.5 mm RC)) compared to adhesive joints (226 N (0.0 RC), 206 N (0.5 mm RC)). For 0.0 RC, the adhesive reinforcement increased the load bearing capacity by 15.6 %. On the contrary, for 0.5 mm RC, the adhesive reinforcement negatively impacted the load bearing capacity and reduced it by 40.6 %. The FSW technique with 0.5 mm RC provides a higher leak path of 77 % remaining tubesheet thickness (> tube thickness) compared to that of 46.6 % (< tube thickness) achieved at 0.0 RC. However, the adhesive reinforcement can enhance the leak path of 0.0 RC FSW joints to around 100 % remaining tubesheet thickness (> tube thickness) by introducing the adhesive material at the tube-sheet interface.

Influences of changes in pH, temperature, and particle size on surface reaction resistance and diffusion resistance in the struvite dissolution process

Struvite (MgNH4PO4·6 H2O，MAP), a type of high-quality, slow-release fertilizer, is the main component of urinary stones in animals and humans and causes scale formation in industrial pipes. Therefore, MAP dissolution is an important research topic. Herein, MAP dissolution experiments are performed and a thermodynamic model is developed to evaluate the influences of pH, temperature (T), and particle size (Ps) on surface reaction resistance (1/ks) and diffusion resistance (1/kd). The results show that MAP solubility decreases with an increase in pH and the effects of pH change are more obvious than those of T or Ps. The total resistance (1/kT) of MAP dissolution increases with pH increase, Ps growth, or T reduction. The comparison of 1/ks and1/kd reveals surface reaction as the MAP dissolution control step and indicates a linear relation among 1/ks, 1/kd, and the natural logarithm of Ps at pH 7.0.

Mechanical Response of an Industrial Piping System Under Strong Cyclic Loading

Abstract The paper presents a combined experimental and numerical investigation of cyclic loading response of an internally pressurized 8-inch-diameter steel piping system. The piping system comprises three elbows and is subjected to quasi-static end-displacement excitation. Global deformation and local strain measurements are obtained, indicating significant strain ratcheting at critical locations of the elbows. The piping system failed under low-cycle fatigue undergoing through-thickness cracking at the flank of the most strained elbow, after 129 loading cycles with measured strain range of approximately 3%. Postfatigue metallographic examination of the elbows indicated that fatigue cracking initiates from the inner surface of the pipe elbow. In all elbows, several microcracks develop along the inner surface of elbow flanks, whereas the outer surface remained practically intact before through-thickness cracking occurred. Finite element simulations, with a cyclic-plasticity model calibrated properly in terms of small-scale material tests, provide very good predictions in terms of local strain evolution at critical locations. Numerical results at the intrados and the extrados of the critical elbow of the piping system verify strain ratcheting and the location of crack initiation observed in the experiments. This paper can be used as a reference for future experiments on cyclic loading of piping components, and for benchmarking constitutive modeling for simulating ratcheting.

Pressure drop of cemented high-concentration backfill in pipe flow: Loop test, model comparison and numerical simulation

Cemented high-concentration backfill (CHB) is an indispensable solution for mitigating risks associated with underground mining voids and surface tailings ponds. The accurate prediction of pressure drop of CHB in pipe flow is crucial for the design of backfilling systems. In this study, full factorial loop tests were conducted to obtain observed pressure drop data and rheological parameters of CHB, while considering the variables of binder content, solid fraction, and flow velocity. The rheometer method was also utilized to acquire the rheological parameters of CHB for comparison. Three analytical models and one numerical simulation method, which are considered highly accurate in the literature, were employed to predict the pressure drop of CHB in pipe flow. The findings indicate that the Buckingham model and the Darby–Melson model produce identical results as they are fundamentally equivalent. The Swamee–Aggarwal model and the single-phase flow simulation employ a similar mechanism as the Buckingham model, albeit with minor variations in mathematical treatment. The rheological parameters of CHB obtained through the rheometer method are considerably greater than those acquired by the loop test method, leading to significantly higher predicted pressure drop values from both the three analytical models and single-phase flow simulation when compared to the measured values. Whereas the mean deviation of the three analytical models is within 6.5% when employing rheological parameters of CHB determined by the loop test, with the Swamee–Aggarwal model being the most accurate, the mean error of single-phase flow simulation remains within 10%. It is suggested that the rheological parameters of CHB be determined through small-diameter loop testing. The Buckingham model and single-phase flow simulation are subsequently recommended for predicting pressure drop in industrial straight horizontal pipelines and complex piping systems, respectively. The results of this study facilitate the selection of the simplest method for accurately predicting the pressure drop of CHB in pipe flow.

Review of the Mechanisms for Preventing, Diagnosing, and Treatment of Pipe Sticking in Drilling Operations

Stuck pipe is a prevalent and costly issue in drilling operations, with the potential to cost the petroleum industry billions of dollars annually. To reduce the likelihood of this issue, efforts have been made to identify the causes of stuck pipes. The main mechanisms that cause stuck pipes include drill cutting of the formation, inappropriate hole-cleaning, wellbore instability, and differential sticking forces, particularly in highly deviated wellbores. The significant consequences of a stuck pipe include an increase in well costs and Non-Productive Time (NPT), and in the worst-case scenario, the loss of a wellbore section and down-hole equipment, or the need to sidetrack, plug, or abandon the well. This paper provides a comprehensive review of the challenges associated with pipe sticking during drilling operations. The mechanisms of pipe sticking, analysis of differential sticking factors, guiding principles to minimize differential sticking, diagnosis approaches, and different treatment methods are discussed. This paper can serve as a guide for any problem involving stuck pipes in the petroleum industry.

Friction stir welding of carbon black reinforced high-density polyethylene tube-to-tubesheet joints

Industrial heat exchanger applications dealing with highly corrosive fluids demand the use of thermoplastic heat exchangers because of the chemically inert and anti-fouling nature of the thermoplastics. A non-conventional joining framework, based on the friction stir welding (FSW) technique, is used to form high-quality thermoplastic tube-to-tubesheet joints (TTJs). The proposed technique has potential applications for thermoplastic shell-and-tube heat exchangers and piping industries (as flange-to-pipe joints). In this work, the tube and tubesheet materials made of carbon black reinforced high-density polyethylene were used. The effect of different FSW parameters (rotational speed, plunge depth, tube protrusion, dwell time) on the tube pull-out behavior was investigated. The FSW technique showed capabilities at a wide range of operating conditions. The highest load bearing capacity of 517 N was achieved using the FSW process, much higher than adhesive joints. Also, it provides higher extensions at maximum load than adhesive joints, with the highest extension of 5.161 mm. Two FSW cases provided high leak paths of 77% and 58% remaining sheet thickness (greater than tube thickness) along with high load bearing capacity and corresponding extensions. The macroscopic and SEM-based fractographic studies illustrated three types of failure behavior: ductile, brittle, or mixed depending on the FSW process conditions. The DSC results showed no significant crystallinity changes in the weld material. The TGA results showed no significant thermal degradation occurring in the weld material. Further, the FTIR analysis indicated possible oxidation of the weld material. The capability to form TTJs with high leak path, high load bearing capacity, and no significant material degradations makes the FSW technique suitable for thermoplastic shell-and-tube heat exchanger applications.

Mechanism of Electrochemical Oxidation of Titanium Via Isotopic Labeling, Medium Energy Ion Scattering, Nuclear Reaction Profiling, in-Situ Rutherford Backscattering Spectrometry, and Electrochemical Impedance Spectroscopy

The few nanometres of titanium oxide present on titanium and Ti alloy surfaces are responsible for protecting the underlying metal from oxidation and enabling its use in many high-performance applications. The oxide provides a hard, uniform, and thermodynamically stable protective coating on an otherwise soft and very reactive metal. Because of its passivating oxide film, titanium has found uses in biomedical implants, aerospace engineering, corrosive industrial piping, and other areas where high strength and low weight are required.Our project is aimed at understanding the atomistic mechanisms of TiO2 formation and growth. We have taken several different approaches to investigate the details of this process. In one approach, the electrochemical oxidation mechanism of titanium at applied potentials between 0 and 10 V vs the saturated calomel reference electrode (SCE) was examined for ultra-thin Ti films sputtered onto Si(001) substrates and exposed in-situ to H2 18O, and then anodized in D2 16O. The effects of this isotopic labeling procedure were studied using medium energy ion scattering (MEIS) and nuclear reaction profiling (NRP). Both MEIS and NRP results are consistent in showing that the titanium oxide layer is composed of two distinct regions (Ti16O2/Ti18O2/Ti/Si) for the entire range of the formation voltages (0–10 V vs SCE). The oxygen component of the outermost region consists entirely of 16O, and the 18O region is always adjacent to the Ti metal. No Ti or 18O loss into the electrolyte solution during anodization was detected. The oxide thickened linearly as a function of potential in the 0–10 V range vs SCE, with experimental anodization ratio of 24.5±0.6 Å V−1. Mott–Schottky (MS) analyses showed positive slopes, indicating formation of an n-type TiO2 semiconductor, with O vacancies (or Ti interstitials) as major charge carriers in the 0–10 V range. Charge carrier densities, ND = (0.8-5.0)×1021 cm−3 were calculated from Mott–Schottky analysis and were well within the range of results reported in the literature. We observed a decrease in the charge carrier densities above ∼4 V vs SCE, that can be connected to defect annihilation or minor modification in the structure (electrostatic annealing) of the growing TiO2 film.In a second approach, we are using Rutherford backscattering spectrometry (RBS) for elemental depth profiling during oxide growth to determine oxidation rates and the role of the anodization potential on the Ti oxide layer structure and morphology. RBS is a powerful ion beam-based analytical tool used to determine thickness at the nanometer scale and elemental depth distribution, making it an excellent choice for studying the thin oxide on titanium. A difficulty with using RBS for such studies has been that RBS must function under ultra-high vacuum, and this has made it incompatible with performing aqueous electrochemistry; therefore, RBS had to be performed as an ex situ analysis, like MEIS and NRP. We are overcoming this limitation by using a specially designed in-situ cell with an ion-permeable silicon nitride window to provide a barrier between the ultra-high vacuum (UHV) required to perform RBS and the aqueous electrolyte solution required for anodization. In this cell, the thin silicon nitride window is coated with titanium and functions as the working electrode when exposed to the aqueous electrolyte solution. RBS measurements are taken as the titanium metal is anodized to titanium oxide. RBS is then performed during in-situ anodization, to obtain information about the growth mechanism of titanium oxide. Our initial in-situ RBS results show a significant increase in the oxidation rate of titanium compared to equivalent ex-situ measurements, and we also observe spontaneous TiO2 film growth without applying an anodic polarization. These effects are likely generated by strongly oxidizing water radiolysis products (e.g., H2O2 or ·OH) formed by the action of high-energy He+ ions interacting with the electrolyte solution.This paper discusses our experimental methods and presents an overview of the results and conclusions of this work.

New Techniques of Recording and Interpretation of Dynamic Coronary Angiography

In the study of coronary artery disease (CAD), the mechanism of plaque formation and development was still the subject of continuing debate. The limitation of the current coronary angiogram (CAG) is that it can only show the static image of a narrowing on the arterial channel without identifying the mechanism of the disease or predicting its progression or regression. Therefore, the current recording of CAGs is reprogrammed by the present team of investigators. The new technique focuses on the identification of blood flow patterns and analysis of their normal or abnormal dynamics by adapting the same methodologies used by hydraulics engineers when moving fluid or gas through domestic or industrial pipes or pumps. This new technique of recording and interpretation of coronary angiography helps to identify different flow patterns in arteries and the application of the fluid dynamics principles to the coronary system. This new technique ushers in a new era of crucial insights and applications regarding the diagnosis, medical, surgical, and interventional management of atherosclerotic diseases.

Novel composites of activated carbon and layered double oxide for the removal of sulfate from synthetic and brackish groundwater

Sulfate (SO42−) is a major water and environmental concern that causes severe diarrhea, death of invertebrates and plant species, and clogging of industrial pipes. In the current work, treatment of SO42− from synthetic and real groundwater having 3901 mg(SO42−)/L was investigated for the first time using Zn–Al and Mg–Al layered double oxides doped granular activated carbon (GAC/Mg–Al LDO and GAC/Zn–Al LDO). The co-precipitation method was followed to synthesize the GAC/LDO composites using an Mg or Zn to Al molar ratio of 3:1. The GAC/Mg–Al LDO possessed a higher specific surface area (323.9 m2/g) compared to GAC/Zn–Al LDO (195.1 m2/g). The GAC/Mg–Al LDO demonstrated more than 99% removal of SO42− from synthetic water, while it was 50.9% for GAC/Zn–Al LDO and less than 1% for raw GAC at an initial concentration of 50 mg/L. The GAC/Mg–Al LDO was selected for further batch experiments and modeling investigation. The equilibrium data followed the Redlich-Peterson and Langmuir models with determination coefficients of 0.943 and 0.935, respectively. The maximum Langmuir adsorption capacity was 143.5 mg/g. In the real groundwater adsorption study, the screening experiment revealed high selectivity towards SO42− with 62% removal efficiency. The optimum dosage was found to be 50 g/L with an uptake capacity of 61.5 mg/g. The kinetic data of SO42− removal from synthetic and brackish water were in excellent agreement with the pseudo-second order model, and the equilibrium was attained in 5 h. Accordingly, it can be concluded that the GAC/Mg–Al LDO is an efficient material for treating SO42− from real groundwater and can be utilized as a pretreatment unit for high sulfate water resources.

A comprehensive experimental study of enhanced solid particle erosive resistance on the inner/outer surface of graphene nanoplatelets modified basalt/epoxy composite pipe

AbstractBasalt fiber reinforced polymer (BFRP) composite pipe is an excellent alternative to glass and carbon fiber reinforced composite pipes in industry and promising in high recycling for polymer composite used in aerospace, marine, and automotive. To enhance the solid particle erosion (SPE) properties of filament‐wound BFRP composite pipe while preserving its mechanical properties, reinforced BFRP composite pipes were prepared to employ non‐functionalized graphene nanoplatelets (GnPs) at a reinforcement concentration of 0.25 wt.% and ultrasonication mixing technique. The SPE behavior of GnPs reinforced and non‐reinforced BFRP composite pipes were characterized by axial and radial positioning of the inner and outer surfaces of the pipes. In each case, the erosion rates of these composite pipes were evaluated at five impingement angles (30°, 45°, 60°, 75°, and 90°) and an impact velocity of 34 m/s. The erosion response of both BFRP composite pipes' outer surfaces showed a semi‐ductile in the axial positioning, with a maximum erosion rate at a 60° impingement angle. However, these composite pipes' inner surfaces in the same positioning presented a maximum erosion rate at a 45° impingement angle. Besides, it is explored that the GnPs contribute to an improvement of approximately 10%–55% in erosive wear resistance of the non‐reinforced BFRP composite pipes. The damage analysis of eroded surfaces was examined through scanning electron microscopy (SEM), and the GnPs effect upon composite pipes' erosion micromechanisms was presented and discussed in detail.Highlights GnPs increased the BFRP composite pipe's erosion resistance. Erosion rate on the inner surface increases due to particle accumulation. GnPs improved erosion behavior via solid lubrication and mechanical properties.

Current level of development and improvement of the design process for tool calibrations of CRP mills

The article presents the results of review analysis of publications of Russian and foreign authors (representatives of both new and established research teams), considering the directions of improvement of existing processes of cold rolling of pipes (CRP). It is shown that for the last decades a major part of studies is devoted to solving different design problems, including the improvement of power elements of electric drive and drive mechanisms, improving of electromechanical system of feeding and turning mechanisms, development of delivery tables structural design, tooth rack, etc. Less attention is paid to finite-element modeling of cold rolling process at tube mills. Separately, the issue of designing of technological tool calibrations of CRP mills has been analyzed. Currently main scientific and technical activities aimed at improving the software and methodological apparatus for designing gauges are focused on specifying individual parameters of already developed earlier classic design procedures and their implementation in various proprietary software products. Examples of modern calculation algorithms, design schemes and main characteristics (advantages and disadvantages, influence on quality indexes of pipes) of current stage of rolling mills technological tools calibrating are given. The functional and technical features of the software products used for this purpose are analyses and the current requirements for modern software are given. Based on the analysis, it is shown that maximum concentration of previously achieved results and their synergy with modern world research trends in calculation methods development of tool profiling in CRP mill is a timely and strategically important task for the domestic pipe industry.

Elastomeric coatings reinforced with fibers for metallic surfaces

Polymeric coatings are widely used on metallic pipes in the mining industry, mainly to prevent corrosion and wear. In this study, natural rubber composite reinforcements were prepared with two different proportions of synthetic, mineral and natural fibers and then evaluated. The composites were initially processed in a closed mixer, followed by homogenization in a cylinder. One of the natural fibers used was assessed with and without previous chemical treatment. The treatments were evaluated with thermogravimetry, Fourier transform infrared spectroscopy and scanning electron microscopy. The rheological, mechanical and wear data for all formulations were also addressed. The glass fiber, polyamide, basalt, and natural jute fiber samples showed reinforcing capabilities similar to that the standard sample (fiber-free composition). The formulations prepared with the chemically treated jute fiber, on the other hand, showed the best mechanical results, adhesion with the metal and abrasion wear resistance. In summary, these formulations prepared with natural raw materials could be alternatives for the composites used to coat industrial pipes.

Effect of recycled material on failure by slow crack growth in multi-layer polyethylene pipes

Among polymer materials, high-density polyethylene (HDPE) is one of the most demanded polymers for packaging as well as in sectors with higher material requirements, such as the plastic pipe industry. The extensive use of HDPE means it is often present in municipal waste. Therefore, there is a high potential for reprocessing and exploring new applications for recycled HDPE, aiming for a circular economy. In the plastic pipe industry, recyclates have found practical use in non-pressure applications. However, the high structural and loading requirements do not allow using it for pressurized pipes yet. The presented study is focused on the possible utilization of recycled HDPE in pressurized pipes in the form of a layer in a multi-layer pipe with two protective layers made of virgin HDPE. The performance of the pipes is assessed based on numerical simulations, coupled with lifetime estimations. The lifetime assessment is based on linear elastic fracture mechanics using experimentally measured slow crack growth (SCG) rates in the virgin and recycled HDPE grades. Thanks to the numerical models, it was possible to describe damage by SCG of the multi-layer pipe as well as to find the dependency of the pipe performance on the thickness ratio and material properties of the layers.