Scale Removal Research Articles

An innovative strategy against oxide spallation of hot formed steels

Hot forming is a prominent technique to produce lightweight automotive steels. However, the generation of a weakly adhering oxide scale during hot forming and the subsequent post-processing of the scale pose a great threat to the shape precision of the product. Here, we propose a cost-effective solution to the spallation issue by incorporating minor silicate-molybdate additives into the rinse following pickling. The pre-deposited film serves as an effective barrier against high-temperature oxidation. Our innovative strategy enables the formation of an oxide scale that sticks to the substrate and paint layer, potentially eliminating the necessity for scale removal in industrial settings.

The Molecular Design of a Macrocycle Descaling Agent Based on Azacrown and the Mechanism of Barium Sulfate Scale Removal.

The formation of barium sulfate scale is a persistent and formidable challenge across various industrial processes. In order to effectively mitigate this problem, this study proposed the development of an innovative azacrown ether-based macrocycle descaling agent. Using density functional theory, an in-depth analysis of the surface energy of different barium sulfate crystal facets was carried out, together with a detailed investigation into the adsorption properties of the functional groups on the (001) surface. A further comprehensive investigation was carried out to determine how changes in the nitrogen and oxygen atoms in the crown ether framework influence its adsorption affinity to barium ions. In addition, a detailed analysis was carried out to elucidate the molecular interactions between crown ethers with pyridine carboxylic acid side chains and barium sulfate. The newly developed decalcifying macrocycle descaling agent exhibited superior adsorption performance, achieving an adsorption energy for barium ions approximately -4.1512 ev higher than that of conventional DTPA decalcifiers. This remarkable improvement is mainly attributed to the pivotal role of electrostatic forces in the coordination process between the macrocycle descaling agent and barium ions, with an electrostatic potential value reaching -143.37 kcal/mol. This discovery not only introduces a novel approach to the removal of barium sulfate scale but also highlights the significant potential of macrocycle chemistry in industrial applications.

Failure analysis of grate in a municipal solid waste incineration plant

The paper presents findings on the mechanisms and consequences of high-temperature corrosion in a waste incineration plant, particularly focusing on the corrosion of gratings made of duplex cast steel. The structure is crucial for corrosion resistance. Symptoms of this corrosion include scale formation and removal, characterized by a two-zone composition: an outer part containing elements such as magnesium, calcium, aluminium, silicon, and oxygen, and an inner part consisting of chromium oxide and iron oxide. Melting traces caused by corrosion in molten salts are also observed on the surface of the scale, and intergranular corrosion and internal oxidation are observed on the cross-section of the grating. Additionally, precipitation processes occur due to long-term heating, leading to the formation of Cr23C6, G and σ phases. These findings underscore the challenges posed by high-temperature corrosion in industrial settings and highlight the complex mechanisms involved in the degradation of materials under such conditions.

Study of the characteristics of fan-shaped impact jets during high-pressure water scale removal

Study of the characteristics of fan-shaped impact jets during high-pressure water scale removal

Socket Array Irregularities and Wing Membrane Distortions at the Eyespot Foci of Butterfly Wings Suggest Mechanical Signals for Color Pattern Determination.

Eyespot foci on butterfly wings function as organizers of eyespot color patterns during development. Despite their importance, focal structures have not been examined in detail. Here, we microscopically examined scales, sockets, and the wing membrane in the butterfly eyespot foci of both expanded and unexpanded wings using the Blue Pansy butterfly Junonia orithya. Images from a high-resolution light microscope revealed that, although not always, eyespot foci had scales with disordered planar polarity. Scanning electron microscopy (SEM) images after scale removal revealed that the sockets were irregularly positioned and that the wing membrane was physically distorted as if the focal site were mechanically squeezed from the surroundings. Focal areas without eyespots also had socket array irregularities, but less frequently and less severely. Physical damage in the background area induced ectopic patterns with socket array irregularities and wing membrane distortions, similar to natural eyespot foci. These results suggest that either the process of determining an eyespot focus or the function of an eyespot organizer may be associated with wing-wide mechanics that physically disrupt socket cells, scale cells, and the wing membrane, supporting the physical distortion hypothesis of the induction model for color pattern determination in butterfly wings.

Descaling of Evaporator Tubes in Sugarcane Factories Using Molasses as a Green and Effective Technology

Deposition inside sugarcane factory evaporators (SFE) significantly lowers the heat transmission and can cause corrosion. This consequently reduces their efficiency, which is clearly a severe issue in the industrial sector. Up to the present time, caustic soda remains the most widely used reagent for descaling sugar industry evaporators. Understanding the scale's composition assists in determining which kinds of cleaners can effectively clean the evaporators. Scales are built in sugar evaporators as a result of the phosphitation or sulfitation processes used to chemically clean juice. In this perspective, molasses is used to descale SFE as a green manner. Molasses includes significant amounts of organic acids and nitrogenous chemical compounds, as shown by GC-mass analysis, and can be utilized as cleaning agents. XRD patterns for four scales from different sugar evaporators indicated that calcium sulfate and calcium phosphate were the predominant components at Egypt's Quos Sugarcane Factory and Dishina Sugarcane Factory, respectively. Actually, dispersed molasses demonstrated an acceptable removal effectiveness of up to 65% in all tested evaporative bodies. Furthermore, molasses solutions were tested in both basic and acidic settings and did not promote corrosion through the body's evaporative tubes. The oxidation of the molasses mixture with air or hydrogen peroxide showed that the efficacy of scale removal decreased. The findings suggested that molasses, as byproduct of sugarcane factories can be successfully employed in descaling as a green cleaning agent. This could be helpful in the development of descaling materials for the industrial sector.

Experimental Study on the Combined Effect of Electromagnetic and Electrochemical Processes on Descaling and Anticorrosion

In this study, a circulating water experimental system was constructed to investigate the scale inhibition, scale removal, corrosion inhibition, and disinfection effects of industrial circulating water under the combined action of electromagnetic and electrochemical fields. The influence of these effects on water quality parameters and their scale inhibition and corrosion inhibition effects on hanging plate experiments were examined. Qualitative and quantitative analyses of scale samples were conducted using XRD (X-ray diffraction) and SEM (scanning electron microscopy), along with the evaluation of changes in water quality parameters (such as conductivity, hardness, Chemical Oxygen Demand (COD), turbidity, iron ions, and chloride ions) before and after the experiments. The results showed that after 360 h of circulation experiment, at a water temperature of 30 °C, electromagnetic field frequency of 1 kHz, electrochemical scale removal device voltage of 24 V, current of 10 A, and water flow rate of 0.6 m/s, the transformation of calcite to aragonite in CaCO3 scale samples occurred, with a 76.6% increase in aragonite content. Moreover, the conductivity decreased by 11.6%, hardness decreased by 42.0%, COD decreased by 59.7%, turbidity decreased by 48.1%, and chloride and iron ion concentrations decreased by 36.6% and 63.1%, respectively. The scale inhibition efficiency reached 53.8%, surpassing the effects of electromagnetic and electrochemical actions individually. These findings demonstrate that the combined action of electromagnetic and electrochemical fields can effectively enhance scale inhibition, scale removal, corrosion inhibition, and disinfection and algae removal effects.

Research and application progress of electrochemical water softening technology in China

The issues of scaling, pipeline corrosion, and the growth of sludge, bacteria, and algae within circulating cooling water systems have been consistently limiting the enhancement of production efficiency in enterprises. The trending new electrochemical water softening technology, with its environmentally friendly, high efficiency, and low energy consumption characteristics, offers a fresh approach to addressing the stable operation of industrial circulating water systems. This paper begins by detailing the mechanisms of active scale removal, sterilization, and algae control facilitated by electrochemical water softening technology. Subsequently, it compares and analyzes the crucial core components of electrochemical devices (including the selection and preparation of anode and cathode materials, as well as the power system). Furthermore, it introduces the main types and installation modes of electrochemical equipment available in the market. Additionally, it uncovers the key factors influencing the efficiency of electrochemical descaling and validates the impact of electrochemical water softening technology on industrial circulating water systems through illustrative examples. Lastly, the paper concludes by summarizing and forecasting the future development direction of this technology.

Pilot scale removal of organic micropollutants by combining ozonation with powdered activated carbon

ABSTRACT Pilot experiments were conducted to assess the removal of organic micropollutants from biologically treated wastewater at a municipal wastewater treatment plant in Sweden. Powdered activated carbon (PAC) was combined with a low dose of ozone added directly before the PAC contact tank, enabling ozone to react simultaneously with the PAC and the wastewater contaminants. This combination of ozone and PAC was compared to PAC or ozone alone. The process, which included coagulation/flocculation and ballasted high-rate lamella sedimentation, proved to be both robust and efficient for the removal of micropollutants. The addition of 1.3 mg PAC/mg DOC resulted in a 73% average reduction of micropollutants. With the addition of 0.13 mg O3/mg DOC, the reduction increased to 83%, which was similar to the outcome with the addition of 26 mg PAC/mg DOC without ozone. The process configuration and operating conditions did not lead to any detectable bromate formation despite relatively high influent bromide levels. The estimated operating costs for combining PAC with a low dose of ozone were significantly lower than for applying a higher PAC dose. Thus, this way of combining PAC with ozone seems to have several advantages with respect to treatment efficiency and operation.

Predictions of locations of flash point and calcite scaling of geothermal fluids in wellbore by chemical and thermodynamic simulations

Geothermal energy, as a renewable energy source, has been intensively developed recently because its utilization can reduce CO2 emission, climate warming and sea level rising, and be beneficial to promote sustainable development. However, scaling in the wellbores often happens during the rising of geothermal fluids. At present, the methods to explore the scaling location principally focus on real measurement techniques and numerical simulation method. In comparison with the former, the latter is extremely time- and labor-saving to predict the scaling location based on the coupling model. In this study, the flash point and scaling locations of two geothermal wells in Hebei province are numerically simulated via ECO2N equation of state module in TOUGHREACT software, and the factors affecting the flash point and scaling locations of geothermal wells are explored. At the same time, the mechanism of geothermal fluid flash is analyzed. The prediction results show that the relative errors of scaling locations in geothermal well I and II are 5.43 % and 6.82 % compared to the field measured data; the pressure and temperature of geothermal fluids at well bottom can be calculated based on the related parameters of wellhead fluid; the locations of flash point and scaling can be determined according to the sudden increases of CO2 partial pressure and scaling amount, respectively. Furthermore, the liquid mass flow rate, CO2 mass flow rate and wellbore diameter have prominent influence on the locations of flash point and scaling, while wellbore diameter have significant effect on the amount of calcite scaling. The above conclusions provide useful guidelines for the next scaling removal and control in the production wellbore during the utilization of the geothermal energy.

Application of Hydrogen Permeation Techniques to Assess the Effect of Inhibitors in Hydrochloric Steel Pickling of Low‐C Steels and Interstitial‐Free Steels

The acid pickling phase, generally entrusted to HCl‐based solutions, plays a fundamental role in the production of low‐C and interstitial‐free steel coils. Very often, however, pickling operations are challenging due to the possible onset of surface defects (underpickling, overpickling, appearance of surface defects, etc.) linked to complex phenomena involving numerous factors, such as acid concentration, Fe ions in solution, temperature, time, steel type, and scale structure. Moreover, the use of inhibitors, which is essential for controlling the pickling process, represents one of the major challenges. Their dosage, although minimal, must be carefully chosen based on the type of processed coils and other plant engineering variables. The flow of hydrogen that is generated on the surface of the steel during etching causes absorption of hydrogen by the metal and its measurement is strictly linked to the phenomena occurring during scale removal. The correlation of data obtained from a Devanathan double‐cell hydrogen permeation system to results of other techniques, such as weight loss, surface analysis, metallography, and electron microscopy shows that this system can be effectively used to indirectly measure the solution aggressiveness. This experimental approach is applied to two industrial steels: a simple carbon base and an interstitial free Ti steel.

Integrated treatment of wax and scale removal in old wells of the Tanjung Field

The majority of oil wells in the Tanjung Field are old wells with reservoir characterized by low pressure and temperature, as well as high water production. The characteristic of oil in the Tanjung Field has a relatively high wax content of 17.61%. This condition has led to several wells in the Tanjung Field experiencing issues with the simultaneous formation of wax and scale deposits within the wellbore equipment. The simultaneous occurrence of wax and scale can significantly impact the production rate. Therefore, addressing this production issue efficiently requires a method known as wax scale removal (WSR). WSR can effectively tackle the problem of wax and scale deposits occurring simultaneously in production equipment. In this method, a solvent for dissolving wax deposits and an acid for dissolving scale are injected together using the huff and puff technique.

Enhancing Skin Cancer Classification using Efficient Net B0-B7 through Convolutional Neural Networks and Transfer Learning with Patient-Specific Data.

Skin cancer diagnosis challenges dermatologists due to its complex visual variations across diagnostic categories. Convolutional neural networks (CNNs), specifically the Efficient Net B0-B7 series, have shown superiority in multiclass skin cancer classification. This study addresses the limitations of visual examination by presenting a tailored preprocessing pipeline designed for Efficient Net models. Leveraging transfer learning with pre-trained ImageNet weights, the research aims to enhance diagnostic accuracy in an imbalanced multiclass classification context. The study develops a specialized image preprocessing pipeline involving image scaling, dataset augmentation, and artifact removal tailored to the nuances of Efficient Net models. Using the Efficient Net B0-B7 dataset, transfer learning fine-tunes CNNs with pre-trained ImageNet weights. Rigorous evaluation employs key metrics like Precision, Recall, Accuracy, F1 Score, and Confusion Matrices to assess the impact of transfer learning and fine-tuning on each Efficient Net variant's performance in classifying diverse skin cancer categories. The research showcases the effectiveness of the tailored preprocessing pipeline for Efficient Net models. Transfer learning and fine-tuning significantly enhance the models' ability to discern diverse skin cancer categories. The evaluation of eight Efficient Net models (B0-B7) for skin cancer classification reveals distinct performance patterns across various cancer classes. While the majority class, Benign Kertosis, achieves high accuracy (>87%), challenges arise in accurately classifying Eczema classes. Melanoma, despite its minority representation (2.42% of images), attains an average accuracy of 80.51% across all models. However, suboptimal performance is observed in predicting warts molluscum (90.7%) and psoriasis (84.2%) instances, highlighting the need for targeted improvements in accurately identifying specific skin cancer types. The study on skin cancer classification utilizes EfficientNets B0-B7 with transfer learning from ImageNet weights. The pinnacle performance is observed with EfficientNet-B7, achieving a groundbreaking top-1 accuracy of 84.4% and top-5 accuracy of 97.1%. Remarkably efficient, it is 8.4 times smaller than the leading CNN. Detailed per-class classification exactitudes through Confusion Matrices affirm its proficiency, signaling the potential of EfficientNets for precise dermatological image analysis.

Research on Geochemical Response Characteristics of Dry Hot Rocks Injected with Scale Removal pH Modified Fluid

Research on Geochemical Response Characteristics of Dry Hot Rocks Injected with Scale Removal pH Modified Fluid

Ultrasound based technology for removal of scale from downhole production tubing, an experimental verification

Deposition and blockages due to scale formation inside the production tubing are the most common problems experienced during the production of oil and gas, and this significantly leads to a decline in the production rate. Progressive scale formation limits production which subsequently leads to abandonment of the well. There is a great cost attached to preventing the occurrence and remediation of scales. Chemical and mechanical techniques for scale removal in production tubing have drawbacks like environmental concerns, equipment damage, and incomplete removal of stubborn scale. In contrast, ultrasound-based methods offer potential benefits such as non-destructiveness, enhanced efficiency, reduced chemical usage, and increased safety for workers. Despite the extensive research about the application of ultrasound to improve oil recovery, there remains a significant gap in the comprehensive exploration of optimum ultrasound parameters (frequency, power, radiation time, interval time, and location) for the removal of in-situ built scales in a simulated production tubing under different flow rates. This study addresses this gap by investigating the impact of ultrasound parameters on its performance for removal of calcium carbonate (CaCO3) and gypsum scales in a simulated production tubing system under different flow rate (100% and 50%). The ultrasound parameters include frequency (in the range of 20 kHz–120 kHz), power (50 W and 100 W), operation time, and location (externally attached and inserted into the production tubing).Initial tests revealed that adjusting the operating frequency improves the impedance matching, resulting in enhanced scale removal. The experiments also explored the influence of flow rate on scale removal, showing a general increase in removal with higher flow rates, specially at operating frequencies 20 kHz and 28 kHz. It was also demonstrated that the higher frequencies of 40 kHz, 68 kHz, and 120 kHz exhibit limited removal efficiency. The effectiveness of scale removal exhibited nonlinear variation over time, with the 28 kHz, 100 W transducer demonstrating the most significant improvement.In-pipe ultrasonic rod, operating at a constant frequency of 26 kHz, was employed to assess its performance for scale removal. Pulsed treatment was introduced to manage rod heating issues. Results demonstrated that both interval times and flow rates influenced CaCO3 removal, with shorter intervals yielding better results. The ultrasonic rod's efficacy was also observed in removing gypsum scale layers, suggesting potential applications in treating scales with various strengths. The results of this study can contribute to a better understanding of how the frequency, power, operating time and interval, and flow rate influence ultrasonic scale removal. The experimental findings provide valuable insights in optimizing practical applications for removal of scales from production tubing.

Personal, financial and time burden in inherited ichthyoses: Asurvey of 144 patients in a university-based setting.

Patients with inherited ichthyosis suffer from scaling due to mutations affecting the epidermal barrier. Symptomatic treatment with ointments, bathing and mechanical scale removal can alleviate the disease, but therapy is time and cost intensive. We investigated costs, time and disease burden of ichthyoses. The study addresses difficulties of the healthcare situation for patients with ichthyoses and reveals potential improvements. We developed a questionnaire addressing time and financial effort for the treatment. Additionally, we collected data of the Dermatology Life Quality Index (DLQI) and the Pruritus Life Quality (5PLQ) questionnaires to determine the impact of ichthyosis and associated pruritus on quality of life (QoL). We recruited 144 patients with ichthyosis (median age: 23; 53.5% female) from the Department of Dermatology in Muenster (Germany) and the German patient support group including common, rare and syndromic subtypes. Eighty-seven percent reported applying topical therapeutics at least once per day, 66.4% several times with an overall median duration of 15 min. Highest single expenditure of time was due to balneotherapy (n = 115; median bathing time: 40 min). In 81.9%, the health insurance did not completely cover the costs for topical treatment causing additional financial burden to the patient with a median of 71 € per quarter, herein creams being the largest cost factor (50 €). Patients with Netherton syndrome showed the highest median expenditure (170 €). The QoL impairment under treatment was moderate (median DLQI: 8.5 points). Pruritus was prevalent in 79.9% and showed a distinct impact on QoL (median 5PLQ: 7.5 points) without any significant difference between the subtypes (p = 0.37). Patients suffering from ichthyoses have a large and lifelong overall burden in mild and severe subtypes. Since continuous topical treatment is required, financial and psychosocial support needs to be considered beyond dermatological care.

Research Progress on Novel Electrochemical Descaling Technology for Enhanced Hardness Ion Removal

In recent years, electrochemical descaling technology has gained widespread attention due to its environmental friendliness and ease of operation. However, its single-pass removal efficiency could be higher, severely limiting its practical application. To overcome the limitations of traditional electrochemical descaling processes, this paper first focuses on the separation efficiency of H+ and OH− in the scale removal process based on numerous recent research papers. It mainly emphasizes how innovative cathode design can enhance the efficiency and stability of electrochemical descaling. Furthermore, this paper explores the coupling of electrochemical processes with different water treatment technologies, such as the combination of electrodeposition with electrocoagulation, filtration crystallization, microfiltration, and electrodialysis, and how these methods synergistically enhance descaling effects. Additionally, this paper discusses potential future directions for electrochemical descaling technology, including innovations in scale expansion, material updates, process optimization, system integration, and automation. Finally, this paper analyzes the practical challenges of electrochemical descaling technology, such as cost, energy consumption, equipment durability, and environmental impact, and proposes solutions. The implementation of these strategies is expected to promote the commercialization of electrochemical descaling technology, making it more aligned with the sustainability requirements of industry and the environment.

DEVELOPMENT OF TEST BENCH FOR EVALUATION OF RESISTANCE OF INTERNAL PROTECTIVE TUBING COATINGS TO INORGANIC SALT DEPOSITS

The formation of inorganic deposits on the working surface of oil and gas equipment is one of the most common causes of failures in oil and gas fields. Inorganic salt deposits formed in tubing reduce pipeline throughput capacity and lead to equipment failure. Thus, the problem of salt formation in tubing is relevant and requires the search for optimal methods to solve it. There are a large number of methods aimed at preventing the formation of inorganic scale and at removing the resulting scale from tubing. The methods of removal of scale from the tubing are expensive, time-consuming, and they require a shutdown at the oil production facility. Therefore, it is preferable to use methods for preventing salt formation in tubing pipes.One of the methods for preventing salt formation in oil production is the use of internal protective coatings of the NKT. It is important to understand that the use of coatings to prevent salt formation is not a universal method, individual selection of the protective coating is required for each object. In addition, at the moment, the effectiveness of the use of protective coatings as a measure to prevent salt formation in the tubing has not been fully proven. The selection of an effective internal coating (to prevent salt formation on the surface of the equipment) using pilot field tests is an expensive and long procedure, so it is necessary to develop a laboratory method and specialized testing equipment to solve this problem. This paper reviewed the existing test equipment to assess its potential for laboratory dynamic testing of tubing coatings under saline conditions. Based on the advantages and disadvantages of existing equipment, the «Stand for assessing the resistance of coatings to inorganic salt deposits» was developed. This article describes the development of the «Test Bench for Evaluation of Coating Resistance to Inorganic Salt Deposits,» which can be used to assess the possibility of using protective tubing coatings to prevent the formation of inorganic salt deposits on the inner surface of pipes.

Electrochemical silica removal from carbon nanotube surfaces: Energy consumption and removal mechanisms

Inorganic fouling, or scaling, is a major challenge for engineered systems exposed to aqueous environments, particularly in water treatment, desalination, or thermal systems where the high salinity and temperature conditions favor surface scaling. Silica, in particular, is hard to remove once a scaling layer forms on the surface. Current scaling mitigation strategies include the addition of antiscalants, physical cleaning by flushing or backwashing, and pretreatment of the feed water. These mitigation strategies increase operation costs due to increased chemical use and system downtime, as well increase the complexity of the process. In this work, we investigated the ability of carbon nanotube (CNT) coatings to disperse silica from the surface via electrochemical reactions, providing a chemical-free approach to scaling control. Silica scaling was induced and then dispersed from CNT coupons upon the application of a potential difference across the experimental set up, with the CNT coupon acting as a cathode or anode. Scale removal was measured using optical coherence tomography at different applied current densities. In this study, a cathodic current of 2.5 A/m2 was found to achieve the highest silica removal: > 75% after 30 min. Control experiments conducted using pH-buffered solutions and pH-insensitive gypsum as the scaling mineral suggest that silica dispersion from the CNT surface was due to a combination of gas evolution and interfacial pH change. These results provide a better understanding of the potential of using electrochemical coatings for the removal of inorganic fouling from surfaces.

CHEMICAL REMOVAL OF IRON SULFIDE DEPOSIT IN PIPES FROM OIL AND SOUR GAS PRODUCTION

Hydrogen sulfide (H2S) and carbon dioxide (CO2) present in oil and natural gas cause mild steel corrosion, potentially resulting in formation of corrosion product layers on the internal surfaces of tubulars. In field experiences relating to the research reported herein, this has led to restrictions on the flow of water produced from a three-phase horizontal separator. This paper demonstrates a specific case of chemical removal of relatively hard, dark, and adherent heterogeneous deposits on the internal surface of the pipe. The phases involved in this process are iron sulfide, iron oxides and calcium carbonate existing as scales/corrosion products. To evaluate their dissolution, laboratory tests were conducted using hydrochloric acid (HCl) with additions of chlorine in the form of calcium hypochlorite [Ca(ClO)2]. Appropriate safety measures were taken employed, considering hazards associated with chlorine and toxicity of hydrogen sulfide. The treatment regime had 87 % effectiveness for scale removal in combination with propargyl alcohol (2-propyn-1-ol) as a corrosion inhibitor.