Pressure Autoclave Research Articles

Effect of powder recycling on corrosion mechanism of plasma sprayed Ni625-WC composite coatings

PurposeThis study aims to investigate the effect of powder recycling on the microstructure of plasma-sprayed Ni625-WC composite coating and to verify the feasibility of Ni625-WC powder recycling by comparing the corrosion resistance of the coatings in high-temperature and pressure CO2 environment.Design/methodology/approachRecycling powder is an efficient way to improve the utilization rate of metal powder during plasma spraying. The plasma-sprayed Ni625-WC composite coatings with original powder (OC) and recovered powder (RC) were analytically compared by using scanning electron microscope (SEM) equipped with an energy-dispersive spectroscopy, X-ray diffractometer, and X-ray photoelectron spectroscopy. The corrosion resistance of the Ni625-WC composite coatings was characterized in a self-designed high-temperature and pressure autoclave by an electrochemical workstation.FindingsThe results showed that there is massive M23C6 in OC and acicular M23C6 in RC. The WC particles in RC are more uniformly distributed, and the area ratios of WC particles to Inconel 625 matrix are 2.37% higher than OC. RC showed high corrosion resistance, and the recycling of Ni625-WC powder is feasible.Originality/valueThe feasibility of Ni625-WC powder recycling was verified from the microstructure evolution and electrochemical behavior of the coatings.

Experimental Assessment of Corrosion Properties for Materials Intended for Heavy Crude Processing.

Heavy crude oil processing presents significant challenges owing to its complex composition and requirement for processing conditions, which increase the process safety risk in crude processing units, such as fixed equipment, for instance pressure vessels and pipes. The aim of this work is to evaluate the influence of heavy crude oils named A and B and the effect of sulfur-rich compounds and organic acids on the performance at high temperatures of three metallic alloys (5Cr-1/2Mo/ASTM A335GP5, X6CrNiMoTi17122/AISI-SAE 316Ti and Ni66.5Cu31.5/Monel 400) and propose an alternative to be used in pressure vessels and piping in refineries. This work was based on the need to understand the corrosivity of two heavy crude oils (A and B) from eastern Colombia in three materials, evaluated at three temperatures (200 °C, 250 °C and 300 °C) under the same conditions of pressure (200 psi) and rotation velocity (600 rpm) in a dynamic autoclave to simulate atmospheric conditions and conditions in vacuum refinery towers. An understanding of how these factors interact with the fundamental principles of corrosion kinetics is essential for developing an effective corrosion mitigation strategy. The results were interesting for applications requiring high corrosion resistance. X6CrNiMoTi17122/AISI-SAE 316Ti is a solid candidate for this application, with corrosion rates of 0.2 to 0.87 mpy. Ni66.5Cu31.5/Monel 400 exhibited significant corrosion rates up to 74.89 mpy, especially at higher temperatures (300 °C). 5Cr-1/2Mo/ASTM A335GP5 showed a generally moderate corrosion rate (2.04-5.57 mpy) in the evaluated temperature range.

Formic and lactic acids from the conversion of xylose with the use of modified clinoptilolite by sonication

AbstractBACKGROUNDA material of natural origin, clinoptilolite, was modified with selected metals in order to obtain a catalyst for the conversion of xylose – the main component of the hemicellulose fraction present in lignocellulosic biomass – to selected carboxylic acids.RESULTSThe starting material without modification (0‐parent), the hydrogen form (0‐hydrogen) of zeolite and zeolite after hierarchization with hydrochloric acid (0‐dealuminated) were used. Iron, copper and cobalt ions were introduced as active centers using the sonication technique. The catalytic process was carried out in a pressure autoclave for 2 h at a temperature of 220 °C. Compounds such as formic acid with a yield of 91% (0‐parent) and lactic acid with a yield of 66.1% (Fe‐hydrogen) were obtained.ConclusionThe catalytic processes carried out using xylose lead to the obtaining of a mixture of carboxylic acids: lactic acid, pyruvic acid and formic acid. An important role here is played by the presence of iron as an active site, which leads to the transformation of xylose into lactic acid by dehydration, and the presence of Lewis and Brønsted active sites. In the case of formic acid, which has never been reported in publications on a similar topic, the starting zeolite without modification contributed to its preparation. It is possible that the content of alkali metals contributed to its preparation along with the coupling of the oxidation reaction of the intermediate product, because of the presence of small amounts of iron, which are present in the natural material. © 2024 Society of Chemical Industry (SCI).

In situ X-ray absorption spectroscopy using the FAME autoclave: a window into fluid-mineral-melt interactions in the Earth’s crust

ABSTRACT We discuss the X-ray absorption spectroscopy (XAS) methods elaborated using the high pressure and high-temperature autoclaves installed at FAME and FAME-UHD beamlines. These methods are based on the in situ acquisition of X-ray transmission and fluorescence spectra of hydrothermal fluids and silicate melts and enable the derivation of both solubility and speciation information about metal complexes. The technological assets of our autoclaves are described across a wide range of experimental conditions spanning from different types of hydrothermal fluids, from liquid-like to vapor-like densities having metal concentrations of <1–10,000 ppm, to magmatic fluid-melt systems at 1000°C. Scientific examples are presented to illustrate the use and the advantages of our spectroscopic ‘micro-batch’ reactors. Finally, the integration of our autoclave setups on the FAME-UHD crystal analyzer spectrometer and the benefits of this technique are demonstrated.

Evaluation of influence of dissolved oxygen on corrosion behaviors of FeCrW model alloys in 360 °C water

Evaluation of influence of dissolved oxygen on corrosion behaviors of FeCrW model alloys in 360 °C water

Corrosion Inhibition Properties of Corrosion Inhibitors to under-Deposit Corrosion of X65 Steel in CO2 Corrosion Conditions.

Under-deposit corrosion is widely present in the pipelines of oil and gas production, causing significant corrosion damage. In this paper, a novel electrochemical cathodic-polarization method was carried out to accelerate the formation of CaCO3 scale on a X65 steel surface in a simulated solution containing scaling ions. Subsequently, pre-scaled X65 steel was placed in a high temperature and pressure autoclave to conduct corrosion weight-loss experiments and in situ electrochemical measurements. The study mainly compared the corrosion inhibition behavior of four quaternary ammonium salt corrosion inhibitors, pyridinium quaternary salt (BPC), quinolinium quaternary salt (BQC), 8-hydroxyquinolinium quaternary salt (BHQ) and pyridinium (1-chloromethyl naphthalene) quaternary salt (1-CPN), in a simulated oilfield scale under corrosive conditions. The results of the weight-loss experiments demonstrated that the inhibition efficiencies of the corrosion inhibitors from high to low were as follows: 1-CPN < BHQ < BQC < BPC. The in situ electrochemical measurements showed that the immersion time and type of corrosion inhibitor had a pronounced influence on the corrosion and corrosion inhibition behavior of X65 steel with CaCO3 coating. It was also proved using both EIS and PC that 1-CPN shows the best inhibition performance in all. Lastly, the inhibition mechanism of corrosion inhibitors at under-deposit conditions was analyzed via a surface morphology observation of SEM.

Corrosion reason analysis and countermeasures of buried oil unloading pipeline in an oilfield

Corrosion reason analysis and countermeasures of buried oil unloading pipeline in an oilfield

Topologically Optimized Graded Foams

The adoption of Nature‐inspired strategies to improve materials has fostered the introduction of cavities. But how to mass‐produce structures in which a complex architecture of cavities is point‐to‐point fine‐tuned to the local and global application requirements? To this aim, the use of a procedure based on topology optimization and gas foaming is herein reported. As an example case, a polymeric foamed beam whose density map is optimized in 3D for three‐point bending is designed and produced by gas foaming a purpose‐designed preform. The preform is produced with polypropylene and by a high pressure autoclave with CO2 as blowing agent. Optical and scanning electron microscopy as well as X‐ray microscopy are used to analyze the 3D optimized foamed structures and show the effectiveness of the foaming design protocol in producing the finite element method‐optimized structures. A remarkable twofold increase in the stiffness of the optimized structures is measured with respect to that of the uniformly foamed counterpart with equal overall mass. With the use of a single recyclable material in a single processing step, this method allows one to conceive the mass production of optimized, therefore more sustainable, plastic parts.

Effects of Porosity on CFRP Repair Performance with Aerospace Applications

On-site repairs of carbon fiber reinforced polymer composites, wet layup repairs with heat blanket method play a critical and practical role for the composite defects that occur in production and assembly. The porosity level should be controlled for the repair parts with heat blanket method since the pressure value, which enables ply consolidation, reduce the risk of delamination in the composite layers, is less or zero with the wet layup repaired parts with heat blanket compared to repair parts with autoclave pressure.&#x0D; In this experimental study, an investigation was conducted regarding the tensile strength change of prepreg structures using wet lay-up repair techniques with heat blanket based on the porosity, with a specific focus on stepped-repaired carbon fiber reinforced polymer laminates.&#x0D; This work aims to understand the strength and the associated failure mechanisms of on-site repaired woven carbon fiber reinforced polymer laminates through experiments. The Automatic Ultrasonic Pulse Echo Inspection Method was utilized to see whether porosity level of each repaired samples is within allowable design limits for this purpose. Prepreg structure's repairs using wet lay-up produced according to standardized aerospace procedures were tested under uniaxial tension per ASTM 3039D. The relationship between attenuation difference (ΔdB) and tensile fracture values has been explored, with a focus on investigating the associated failure mechanisms. Initially, a 60% strength recovery was observed for repairs with an 8-decibel difference. However, as the decibel difference increased, the strength recovery gradually decreased, ultimately reaching 45.2%.

Phytochemicals, antioxidant capacities and volatile compounds changes in fermented spicy Chinese cabbage sauces treated by thermal and non-thermal technologies

To extend shelf life of fermented spicy Chinese cabbage sauce at room temperature, the effects of electron beam irradiation (EBI), high pressure processing (HPP), pasteurization (PT) and autoclave sterilization (AS) treatments on the colony counts of Lactobacillus plantarum, phytochemicals, antioxidant activities and volatile compounds were investigated. Results showed that thermal and non-thermal treatments could significantly decrease the colony counts of Lactobacillus plantarum, in which EBI and AS treatments inactivated Lactobacillus plantarum thoroughly. EBI and HPP treatments were superior to PT and AS treatments in terms of volatile compounds, bioactive compounds and antioxidant activities. The total contents of volatile compounds in sauces treated by EBI and HPP were significantly increased by 43.92%-61.87% and 71.53%-84.46%, respectively, and the new formed substance 2,3-butanedione endowed sauces with sweet and creamy aroma. In addition, HPP treatment improved the extractable contents of total phenolics and carotenoids, retained capsicum red pigment content, and significantly enhanced antioxidant capacities of sauces. Sauce treated by HPP at 200MPa exhibited the highest total carotenoid content, DPPH radical scavenging activity and FRAP, increasing by 9.27%, 2.24% and 16.13%, respectively, compared with CK. EBI treatment exhibited higher total phenolic content and FRAP, which positively depended on the dose. Therefore, HPP and EBI treatments were suggested as potential technologies to improve shelf-life stability and volatile compounds of fermented spicy Chinese cabbage sauce.

A Study on the Hydrothermal Synthesis of Calcium Silicate Products by Calcination of Full-Component Waste Concrete

In order to achieve the reuse of waste concrete, the hydrothermal synthesis of low-temperature calcined calcium silica products with an ideal admixture of fly ash and waste concrete as raw materials was investigated and various properties were studied. The findings suggest that the optimal method involves adding 10% fly ash to waste concrete to lower the temperature at which calcium carbonate decomposes. The compressive strength of the specimens generally increases with increasing calcium–silicon ratio and pressure can reach up to 43.98 MPa. Nevertheless, the duration of holding requires adjustment in line with autoclave pressure: the higher the pressure, the shorter the holding time, and vice versa for lower pressure. Most of the specimens are water-resistant with softening coefficients above 0.6 and up to 0.91. The macroscopic strength is determined by the way in which the microstructure of the hydration products forms under different conditions. The optimum design for the experimental conditions should be that the pressure, holding time and calcium–silica ratio should be 1.0 MPa, 9 h and 1.0, respectively. Due to their potential for resource conservation and environmental improvement, autoclaved silicate materials manufactured from waste concrete may be a viable alternative as a green construction material.

Utilizing an Ultrasonic Inspection System Operating Inside an Autoclave and Machine Learning to Quantify Porosity within Composites During Cure

ABSTRACT Composite materials are increasingly being utilized in aerospace applications for their high stiffness and strength to weight ratios and fatigue resistance. However, defects in the composite may arise during cure (e.g. porosity, delamination, fiber waviness), and current technology only allows for post-cure evaluation (e.g. microscopy, ultrasonic inspection). A high-temperature ultrasonic scanning system was developed for deployment in an autoclave, which can detect porosity in composites during the cure process. This study focused on the implementation of machine learning techniques to help generate a model that can quantify porosity, in addition to detection and localization that has previously been demonstrated. Two, six-hour-long experiments were conducted on curing of 762 mm × 305 mm (30 in. ×12 in.) composite panels with a [0/45/90/-45]4s layup and varying regions of high and low pressure due to its tapered geometry in contact with a flat caul plate. The first experiment utilized a thick (12.7 mm) caul plate and the second utilized a thin (3.2 mm) caul plate. During experimentation, within the scan area (406 mm × 13 mm), data was recorded and stored for ultrasonic amplitude. Additional variables were measured or predicted including temperature, autoclave pressure, number of plies, slope of the composite panel surface with respect to the transducer, viscosity, and glass transition temperature. The pre-processed data was entered into the Regression Learner Application in MATLABⓇ,1 and a rational quadratic Gaussian process regression (GPR) was chosen for the machine learning algorithm. The model was then trained on a larger data set to make it more robust and capable of predictions using a function callout. The result was a machine learning algorithm that can reliably quantify porosity in a composite panel during cure based on measured amplitude response and generate images for intuitive visualization. This tool can be further trained with more experimentation and potentially employed for real-time porosity detection and quantification of composite components during cure in an autoclave. Practical use of this technology is the potential to dynamically control processing parameters (e.g. autoclave pressure) in real-time to reduce the level of porosity within the laminate to acceptable limits (e.g. 2% by volume).

Conversion of waste into wealth in chemical recycling of polymers: Hydrolytic depolymerization of polyethylene terephthalate into terephthalic acid and ethylene glycol using phase transfer catalysis

Conversion of waste into wealth in chemical recycling of polymers: Hydrolytic depolymerization of polyethylene terephthalate into terephthalic acid and ethylene glycol using phase transfer catalysis

Oxidative carbonylation of propylene glycol to propylene carbonate by copper-based catalysts

Oxidative carbonylation of propylene glycol to propylene carbonate by copper-based catalysts

Surface Phenomena with the Participation of Sulfite Lignin under Pressure Leaching of Sulfide Materials.

Searching for surfactants which can eliminate the occluding effect of molten elemental sulfur formed in the process of leaching sulfide ores under pressure (autoclave leaching) is relevant. However, the choice and use of surfactants are complicated by the harsh conditions of the autoclave process, as well as the insufficient knowledge of surface phenomena in their presence. This paper presents a comprehensive study of interfacial phenomena (adsorption, wetting, and dispersion) involving surfactants (using lignosulfonates as an example) and zinc sulfide/concentrate/elemental sulfur under conditions simulating sulfuric acid leaching of ores under pressure. The influence of concentration (CLS 0.1-1.28 g/dm3), features of the molecular weight (M̅w, 9.250-46.300 Da) composition of lignosulfates, temperature (10-80 °C), addition of sulfuric acid (CH2SO4 0.2-10.0 g/dm3), and properties of solid-phase objects (surface charge, specific surface area, presence and diameter of pores) on surface phenomena at the liquid-gas and liquid-solid interfaces was revealed. It was found that with an increase in molecular weight and a decrease in the degree of sulfonation, the surface activity of lignosulfonates at the liquid-gas interface, as well as their wetting and dispersing activity with respect to zinc sulfide/concentrate increases. It has been found that an increase in temperature contributes to the compaction of the macromolecule of lignosulfonates, as a result of which their adsorption at the liquid-gas and liquid-solid interface in neutral media rises. It has been shown that the introduction of sulfuric acid into aqueous solutions increases the wetting, adsorption, and dispersing activity of lignosulfonates with respect to zinc sulfide. The latter is accompanied by a decrease in the contact angle θ (by 10 and 40°) and an increase in both the specific number of zinc sulfide particles (not less than 1.3-1.8 times) and the content of fractions with a size of -3.5 μm. It has been established that the functional effect of lignosulfonates under conditions simulating sulfuric acid autoclave leaching of ores is implemented through the adsorption-wedging mechanism.

High-Pressure FDM 3D Printing in Nitrogen [Inert Gas] and Improved Mechanical Performance of Printed Components

Fundamentally, the mechanical characteristics of 3D-printed polymeric objects are determined by their fabrication circumstances. In contrast to traditional polymer processing processes, additive manufacturing requires no pressure during layer consolidation. This study looks at how a high-pressure autoclave chamber without oxygen affects layer consolidation throughout the fused deposition modelling process, as well as the mechanical qualities of the products. To attain high strength qualities for 3D-printed components such as injection-molded specimens, an experimental setup consisting of a 3D printer incorporated within a bespoke autoclave was designed. The autoclave can withstand pressures of up to 135 bar and temperatures of up to 185 °C. PLA 3D printing was carried out in the autoclave at two different pressures in compressed air and nitrogen atmospheres: 0 bar and 5 bar. Furthermore, injection molding was done using the same PLA material. Tensile, flexural, and Charpy tests were carried out on samples that were 3D printed and injection molded. In nitrogen, oxidation of the environment was prevented by autoclave preheating before printing, and autoclave pressure during printing considerably promotes layer consolidation. This imprinted mechanical strength on the 3D-printed items, which are virtually as strong as injection-molded components.

Investigation of Stress Corrosion Cracking Resistance of Irradiated 12Cr Ferritic-Martensitic Stainless Steel in Supercritical Water Environment

The supercritical water-cooled reactors (SWCR) belong to Generation IV of reactors. These reactors have a number of advantages over currently operating WWERs and PWRs. These advantages include higher thermal efficiency, a more simplified unit design, and the possibility of incorporating it into a closed fuel cycle. It is therefore necessary to identify candidate materials for the SWCR and validate the safety and effectiveness of their use. 12Cr ferritic-martensitic (F/M) stainless steel is considered a candidate material for SWCR internals. Radiation embrittlement and corrosion cracking in the primary circuit coolant environment are the main mechanisms of F/M steels degradation during SWCR operation. Here, the stress corrosion cracking (SCC) in supercritical water at 390 and 550 °C of 12Cr F/M steel irradiated by neutrons to 12 dpa is investigated. Autoclave tests of specially designed disk specimens in supercritical water were performed. The tests were carried out under different constant load (CL), temperature 450 °C, and pressure in autoclave 25 MPa. The threshold stress, below which the SCC initiation of irradiated 12Cr F/M steel does not occur, was determined.

Development of activated carbon by bio waste material for application in supercapacitor electrodes

Development of activated carbon by bio waste material for application in supercapacitor electrodes

TRANSFORMATIONS OF 5-HYDRAZINYL-1,2,4-TRIAZINES IN THE REACTION WITH 2,5-NORBORNADIENE

The interaction between 5-hydrazinyl-substituted 1,2,4-triazines and 2,5-norbornadiene at elevated temperature and pressure (in autoclave) have been studied. The 2-aminopyridines, 5-amino-1,2,4-triazines and 6-unsubstituted pyridines are the products of this reaction. The formation of last two products depends on the substituent at C3 position of the triazine.

A Simple Model for Inflexed Multilayered Laminated Glass Beams Based on Refined Zig-Zag Theory

Abstract Laminated glass is a composite made of glass plies sandwiching polymeric interlayers, permanently bonded with a process at high pressure and temperature in autoclave. Within the quasi-elastic approximation, according to which the polymer is linear elastic material whose elastic modulus parametrically depends upon time and environmental temperature, we present a model for inflexed laminated-glass beams in the pre-glass-breakage phase. The approach relies on a modified version of the refined zig-zag theory for composites, in which the glass plies are treated as Euler–Bernoulli beams, whereas the interlayers can only provide a shear-stiffness contribution to the coupling of the glass plies. The kinematic description is greatly simplified and the governing equations can be solved analytically, for laminated packages of any type, when the beam is statically determined. A finite element implementation is proposed for the most general cases. The convergence analysis for the numerical approach and the comparison with the analytical solution in benchmark problems demonstrate the efficiency of the proposed method.