Hole cleaning evaluation and installation spacing optimization of cuttings bed remover in extended-reach drilling

In extended-reach or long-horizontal drilling,cuttings usually deposit at the bottom of the annulus.Once cuttings accumulate to a certain thickness,complex problems such as excessive torque and drag,tubing buckling,and pipe stuck probably occur,which results in a lot of non-productive time and remedial operations.Cuttings bed remover can efficiently destroy deposited cuttings in time through hydraulic and mechanical stirring effects.This paper aims to build a method for hole cleaning evaluation and installation spacing optimization of cuttings bed remover to improve the wellbore cleaning effect.Firstly,a Computational Fluid Dynamics approach with Eulerian—Eulerian multiphase model was utilized to investigate the mechanism of cuttings transportation,and a new type of cuttings bed remover was designed.Next,an evaluation method of hole cleaning effect of remover was established.After that,the effects of several drilling parameters on hole cleaning including flow rate of drilling fluid,rotational speed of drillpipe,rate of penetration,wellbore size,rheological property of drilling fluid,and remover eccentricity on the performance of cuttings bed remover were investigated.The results demonstrate that the new type of remover with streamline blade performs better than conventional removers.The efficiency of hole cleaning is greatly improved by increasing the rotational speed of drillpipe,flow rate of drilling fluid,remover eccentricity,and 6 rpm Fann dial reading for drilling fluid.While higher rate of penetration and large wellbore size result in worse hole cleaning.These findings can serve as an important guide for the structure optimization design of cuttings bed remover and installation spacing of removers.

Surface activity and cleaning performance of rosin-based quaternary ammonium salt type asymmetric Gemini surfactants

Rosin,a renewable and abundant resource,has been extensively processed and chemically modified to endow it with special properties,especially in the surfactant industry.In this study,four rosin-based quaternary ammonium asymmetric gemini surfactants(RGS-2-n)with different alkyl chain lengths(n=12,14,16,18)were synthesized using a simple two-step method based on dehydroabietylamine as the raw material.The feasibility of these surfactants for cleaning purposes was comprehensively evaluated,suggesting that the surfactants own high surface activity and good cleaning performance.Furthermore,by successfully introducing the amine group of dehydroabietylamine into the hydrophilic group of the surfactants,we avoided its potential harm to the environment and water pollution.Density functional theory proves rosin-based gemini surfactants with asymmetric structure can further improve cleaning efficiency.Overall,our findings suggests that RGS-2-n surfactants are promising and sustainable candidates for cleaning electric plates,and provide new opportunities for rosin application in the electric industry.

Cleaning of two mirrors in the first mirror unit using radiofrequency capacitively coupled plasma

First mirror(FM)cleaning,using radio frequency(RF)plasma,has been proposed to recover FM reflectivity in nuclear fusion reactors such as the International Thermonuclear Experimental Reactor(ITER).To investigate the influence of simultaneous cleaning of two mirrors on mirror cleaning efficiency and uniformity,experiments involving single-mirror cleaning and dual-mirror cleaning were conducted using RF capacitively coupled plasma in the laboratory.For the test and simultaneous cleaning of two mirrors,the FM and second mirror(SM),both measuring 110 mm×80 mm,were placed inside the first mirror unit(FMU).They were composed of 16 mirror samples,each with a dimension of 27.5 mm×20 mm.These mirror samples consist of a titanium-zirconium-molybdenum alloy substrate,a 500 nm Mo intermediate layer and a 30 nm Al_(2)O_(3) surface coating as a proxy for Be impurities.The cleaning of a single first mirror(SFM)and the simultaneous cleaning of the FM and SM(DFM and DSM)lasted for 9 h using Ar plasma at a pressure of 1 Pa.The total reflectivity of mirror samples on the DSM did not fully recover and varied with location,with a self-bias of−140 V.With a self-bias of−300 V,the total reflectivity of mirror samples on the SFM and DFM was fully recovered.The energy dispersive spectrometer results demonstrated that the Al_(2)O_(3) coating had been completely removed from these mirror samples.However,the mass loss of each mirror sample on the SFM and DFM before and after cleaning varied depending on its location,with higher mass loss observed for mirror samples located in the corners and lower loss for those in the center.Compared with SM cleaning,the simultaneous cleaning of two mirrors reduced the difference between the highest and lowest mass loss.Furthermore,this mass loss for the mirror samples of the DFM facing the DSM was increased.This indicated that mirror samples cleaned face to face in the FMU simultaneously could influence each other,highlighting the need for special attention in future studies.

A method for cleaning wind power anomaly data by combining image processing with community detection algorithms

Current methodologies for cleaning wind power anomaly data exhibit limited capabilities in identifying abnormal data within extensive datasets and struggle to accommodate the considerable variability and intricacy of wind farm data.Consequently,a method for cleaning wind power anomaly data by combining image processing with community detection algorithms(CWPAD-IPCDA)is proposed.To precisely identify and initially clean anomalous data,wind power curve(WPC)images are converted into graph structures,which employ the Louvain community recognition algorithm and graph-theoretic methods for community detection and segmentation.Furthermore,the mathematical morphology operation(MMO)determines the main part of the initially cleaned wind power curve images and maps them back to the normal wind power points to complete the final cleaning.The CWPAD-IPCDA method was applied to clean datasets from 25 wind turbines(WTs)in two wind farms in northwest China to validate its feasibility.A comparison was conducted using density-based spatial clustering of applications with noise(DBSCAN)algorithm,an improved isolation forest algorithm,and an image-based(IB)algorithm.The experimental results demonstrate that the CWPAD-IPCDA method surpasses the other three algorithms,achieving an approximately 7.23%higher average data cleaning rate.The mean value of the sum of the squared errors(SSE)of the dataset after cleaning is approximately 6.887 lower than that of the other algorithms.Moreover,the mean of overall accuracy,as measured by the F1-score,exceeds that of the other methods by approximately 10.49%;this indicates that the CWPAD-IPCDA method is more conducive to improving the accuracy and reliability of wind power curve modeling and wind farm power forecasting.

Investigation of an electrode-driven hydrogen plasma method for in situ cleaning of tin-based contamination

To prolong the service life of optics,the feasibility of in situ cleaning of the multilayer mirror(MLM)of tin and its oxidized contamination was investigated using hydrogen plasma at different power levels.Granular tin-based contamination consisting of micro-and macroparticles was deposited on silicon via physical vapor deposition(PVD).The electrodedriven hydrogen plasma at different power levels was systematically diagnosed using a Langmuir probe and a retarding field ion energy analyzer(RFEA).Moreover,the magnitude of the self-biasing voltage was measured at different power levels,and the peak ion energy was corrected for the difference between the RFEA measurements and the self-biasing voltage(E_(RFEA)-eV_(self)).XPS analysis of O 1s and Sn 3d peaks demonstrated the chemical reduction process after 1 W cleaning.Analysis of surface and cross-section morphology revealed that holes emerged on the upper part of the macroparticles while its bottom remained smooth.Hills and folds appeared on the upper part of the microparticles,confirming the top-down cleaning mode with hydrogen plasma.This study provides an in situ electrode-driven hydrogen plasma etching process for tin-based contamination and will provide meaningful guidance for understanding the chemical mechanism of reduction and etching.

Wellbore Cleaning Degree and Hydraulic Extension in Shale Oil Horizontal Wells

The efficient development and exploitation of shale oil depends on long-distance horizontal wells. As the degreeof cleaning of the wellbore plays a key role in these processes, in this study, this problem is investigated experimentallyby focusing on the dimensionless cuttings bed height. A method is proposed to calculate the horizontalwellhydraulic extension taking into account the influence of the wellbore cleaning degree on the wellborepressure distribution and assess the effect of a variety of factors such as the bottom hole pressure, the circulatingpressure drop, the drilling pump performance and the formation properties. The analysis shows that the hydraulicextension of horizontal wells decreases with an increase in the cuttings bed height, and the higher the displacementof drilling fluid, the faster the hydraulic extension declines. The annular pressure drop of the horizontalsection increases with the increase of the cuttings bed height, resulting in a higher bottom-hole pressure. Severalarguments are provided to guide the safe drilling of shale oil horizontal wells and overcome the limits of currenttechnological approaches.

Overview of Factors Affecting Dust Deposition on Photovoltaic Cells and Cleaning Methods

Dust deposition on the surface of photovoltaic (PV) cells poses a significant challenge to their efficiency, especially in arid regions characterized by desert and semi-desert conditions. Despite the pronounced impact of dust accumulation, these regions offer optimal solar radiation and minimal cloud cover, making them ideal candidates for widespread PV cell deployment. Various surface cleaning methods exist, each employing distinct approaches. Choosing an appropriate cleaning method requires a comprehensive understanding of the mechanisms involved in both dust deposition on module surfaces and dust adhesion to PV cell surfaces. The mechanisms governing dust deposition and adhesion are complex and multifaceted, influenced by factors such as the nature and properties of the dust particles, environmental climatic conditions, characteristics of protective coatings, and the specific location of the PV installation. These factors exhibit regional variations, necessitating the implementation of diverse cleaning approaches tailored to the unique conditions of each location. The first part of this article explores the factors influencing dust deposition on PV cell surfaces, delving into the intricate interplay of environmental variables and particle characteristics. Subsequently, the second part addresses various cleaning methods, offering an analysis of their respective advantages and disadvantages. By comprehensively examining the factors influencing dust accumulation and evaluating the effectiveness of different cleaning strategies, this article aims to contribute valuable insights to the ongoing efforts to optimize the performance and longevity of photovoltaic systems in diverse geographical contexts.

A Diamond Electrochemical Cleaning Technique for Organic Contaminants on Silicon Wafer Surfaces

Peroxodiphosphate anion （a powerful oxidant） can be formed in a special water-based cleaning agent through an electrochemical reaction on boron-doped diamond electrodes. This electrochemical reaction was applied during the oxidation,decomposition, and removal of organic contaminations on a silicon wafer surface, and it was used as the first step in the diamond electrochemical cleaning technique （DECT）. The cleaning effects of DECT were compared with the RCA cleaning technique, including the silicon surface chemical composition that was observed with X-ray photoelectron spectroscopy and the morphology observed with atomic force microscopy. The measurement results show that the silicon surface cleaned by DECT has slightly less organic residue and lower micro-roughness,so the new technique is more effective than the RCA cleaning technique.

Technical Regulations on Cleaning Processing of Feeding Millet Seeds in Hebei Province

According to many years of experimental summary, the technical demands, process control, seed test, seed quality and work record （ledger management） of cleaning processing of feeding millet seeds in Hebei Province were studied, and specific measures and technical indicators of the technical regulations were analyzed to provide normalized, standardized, industrial and marketization technical support for the cleaning processing of feeding millet seeds.

Cleaning the Ion Exchange Resin Sorption of Uranium from Silicic Acid Solution ＂Ayanat＂

The authors discovered a new way to clean the ion exchange resin sorption of uranium from silicic acid used solution ＂Ayanat＂. The method reduces the costs of regeneration of ion exchange resin and its reuse in the sorption of uranium.

Deep cleaning of a metallurgical zinc leaching residue and recovery of valuable metals

Huge quantities of zinc leaching residues(ZLRs) generated from zinc production are dumped continuously around the world and pose a potential environmental threat because of their considerable amounts of entrained heavy metals(mainly lead). Most ZLRs have not been properly treated and the valuable metals in them have not yet been effectively recovered. Herein, the deep cleaning of a ZLR and recovery of valuable metals via a hydrometallurgical route were investigated. The cleaning process consists of two essential stages: acid leaching followed by calcium chloride leaching. The optimum conditions for extracting zinc, copper, and indium by acid leaching were a sulfuric acid concentration of 200 g·L^(-1), a liquid/solid ratio of 4:1(m L/g), a leaching time of 2 h, and a temperature of 90°C. For lead and silver extractions, the optimum conditions were a calcium chloride concentration of 400 g·L^(-1), a pH value of 1.0, a leaching time of 1 h, and a temperature of 30°C. After calcium chloride leaching, silver and lead were extracted out and the lead was finally recovered as electrolytic lead by electrowinning. The anglesite phase, which poses the greatest potential environmental hazard, was removed from the ZLR after deep cleaning, thus reducing the cost of environmental management of ZLRs. The treatment of chlorine and spent electrolyte generated in the process was discussed.

Review of Underwater Ship Hull Cleaning Technologies

This paper presents a comprehensive review and analysis of ship hull cleaning technologies.Various cleaning methods and devices applied to dry-dock cleaning and underwater cleaning are introduced in detail,including rotary brushes,high-pressure and cavitation water jet technology,ultrasonic technology,and laser cleaning technology.The application of underwater robot technology in ship cleaning not only frees divers from engaging in heavy work but also creates safe and efficient industrial products.Damage to the underlying coating of the ship caused by the underwater cleaning operation can be minimized by optimizing the working process of the underwater cleaning robot.With regard to the adhesion technology mainly used in underwater robots,an overview of recent developments in permanent magnet and electromagnetic adhesion,negative pressure force adhesion,thrust force adhesion,and biologically inspired adhesion is provided.Through the analysis and comparison of current underwater robot products,this paper predicts that major changes in the application of artificial intelligence and multirobot cooperation,as well as optimization and combination of various technologies in underwater cleaning robots,could be expected to further lead to breakthroughs in developing next-generation robots for underwater cleaning.

Modes of Occurrence and Cleaning Potential of Trace Elements in Coals from the Northern Ordos Basin and Shanxi Province, China

Based on the analyses of 43 elements in 16 samples of the raw coal and feed coal collected from the northern Ordos basin and Shanxi Province, the modes of occurrence of these elements were studied using the method of cluster analysis and factor analysis, and the cleaning potential of the hazardous elements relatively enriched in the coals was discussed by analyzing six samples of the cleaned coal from the coal-washing plants and coal cleaning simulation experiments. The results shows that the elements Br and Ba show a strong affinity to the organic matter, Cs, Cd, Pb, Zn and Hg partly to the organic matter, and the other trace elements are mainly associated with the mineral matter. Cs, Mo, P, Pb, Zn and S have positive correlations with the two principal factors, reflecting the complexity of their modes of occurrence. Some elements that were thought to show a faint relationship (Be with S and Sb with carbonates) in other rocks are found to have a strong interrelation in the coals. Clay minerals (mainly kaolinite) dominate in the coals, and Ta, Th, Ti, Sc, REE, Hf, U, Se, W, V, Nb, Mo, Al, P, Cr, Pb and Zn are distributed mostly in kaolinite, while K, Rb, Cs, and Na have much to do with illite. Conventional cleaning can reduce the concentrations of most hazardous elements in various degrees. The hazardous elements S, As, Sb, Se, Mo, Pb, Cd and Hg relatively enriched in some coals from the area studied have a relatively high potential of environmental risks. However, by physical coal cleaning processes, more than 60% of As and Hg were removed, showing a high degree of removal, more than 30% of Sb, as well as S, Pb and Cd partly associated with the inorganic matter were removed. Se and Mo showing a relatively low degree of removal could be further removed by deep crushing of the coal during physical cleaning processes, and the concentrations of S, Pb, Cd and Hg with a partial association with the organic matter could be decreased in such ways as the coal blending. Cluster analysis together with factor analysis is a rapid and effective way to deduce the mode of occurrence of an element from bulk samples, and the removability data of most hazardous elements are basically consistent with their modes of occurrence suggested, which indicates that the statistical analysis could predict the cleaning potential of hazardous elements during the physical coal cleaning.

Simultaneous Optimization of Synthesis and Scheduling of Cleaning in Flexible Heat Exchanger Networks

A novel methodology is presented for simultaneously optimizing synthesis and cleaning schedule of flexible heat exchanger network(HEN)by genetic/simulated annealing algorithms(GA/SA).Through taking into account the effect of fouling process on optimal network topology,a preliminary network structure possessing two-fold oversynthesis is obtained by means of pseudo-temperature enthalpy(T-H)diagram approach prior to simultaneous optimization.Thus,the computational complexity of this problem classified as NP(Non-deterministic Polynomial)-complete can be significantly reduced.The promising matches resulting from preliminary synthesis stage are further optimized in parallel with their heat exchange areas and cleaning schedule.In addition,a novel continu- ous time representation is introduced to subdivide the given time horizon into several variable-size intervals according to operating periods of heat exchangers,and then flexible HEN synthesis can be implemented in dynamic manner.A numerical example is provided to demonstrate that the presented strategy is feasible to decrease the total annual cost(TAC)and further improve network flexibility,but even more important,it may be applied to solve large-scale flexible HEN synthesis problems.

Effect of the Ultrasound Generated by Flat Plate Transducer Cleaning on Polluted Polyvinylidenefluoride Hollow Fiber Ultrafiltration Membrane

Polyvinylidenefluoride （PVDF） hollow fiber ultrafiltration membrane is frequently employed in water treatment. However, the fouling of ultrafiltration membranes affects the economic effectiveness of such process significantly. The ultrasound generated by flat plate transducer （UFPT） was used to clean the polluted PVDF ultrafiltration membrane with 2 g·L^-1 of citric acid aqueous solution in our study. The effects of UFPT intensity on the membrane surface were studied. The new membrane was easy to be polluted by the saturated CaCl2 solution. A synergistic effect of UFPT and 2 g·L^-1 citric acid aqueous solution could remove the foul of the membrane, and its flux could be recovered about 81%. The flux recovery of old membrane polluted was increased to 73.2% after 7 h soaking in citric acid aqueous solution, but its flux recovery without soaking was only increased to 56.2%.

Damage and deterioration mechanism and curing technique of concrete structure in main coal cleaning plants

Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Datun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the special natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants.

Optimization of Nozzle Design for Pulse Cleaning of Ceramic Filter

The experimental study was carried out to optimize the nozzle shape and dimension for the pulse cleaning of a ceramic filter candle. A bench scale unit of ceramic filter consisting of four commercial filter elements was used to measure the traces of the transient pressure around the nozzle and the overpressure in the filter cavity during the pulse-jet injection of pulse gas. Overpressure in the filter cavity is related to the pulse cleaning force. Nozzle design is concerned to increase the overpressure at the open end of filter element of pulse cleaning inlet, as well as to minimize the consumption of pulse gas. Convergent nozzle induces more secondary flow and generates higher pulse cleaning effect than straight nozzle. Nozzles of different convergent ratio （ratio of outlet to inlet diameter of nozzle） by changing the convergent angle and height were tested. The outlet diameter of convergent nozzle seriously influences the cleaning effect. The optimum convergent ratio increases with the increase of pulse gas pressure The nozzle position （distance of nozzle tip from the open end of filter inlet） is also important to decide the nozzle dimension. Nozzle of large outlet diameter accepts high pressure of pulse gas to provide large overpressure in the filter cavity of top position by applying long distance.

The design of underwater hull-cleaning robot

The research on underwater ship-hull cleaning robot was conducted on the purpose of realizing the automation of cleaning underwater ship hull so that service life of ship will be prolonged and ship speed will raised. Moreover, fuel consumption and the work intensity of divers will be reduced. In this paper, the current situation and the latest technology in China and abroad were analyzed;meanwhile, the typical characteristics of the underwater cleaning robot were introduced. According to the work principle of the underwater cleaning robot, the emphasis was put on the analysis and study of permanent-magnetic absorption, magnetic wheel, airproof and anticorrosion, underwater cleaning equipment and control system. The robot is easy in rotation and simple in control.

Fouling and cleaning of membrane——a literature review

Membrane fouling curtails severely the economical and practical implementation of membrane process. The fundamental principles and mechanisms of membrane fouling as well as factors affecting fouling have been summarized in this paper. It also has covered three fouling resistance models and four kinds of approaches to improve membrane performance. Membrane cleaning methods are also discussed including physical, chemical, physico\|chemical and biological methods. In the four groups of basic cleaning methods, biological cleaning has considerable advantages and potentials. Extensive research work should be carried out further to explore and develop new ideas and techniques in the field of membrane cleaning and restoration.

Application of response surface methodology to the chemical cleaning process of ultrafiltration membrane

A numerical model was established to predict and optimise the chemical cleaning process of Polyvinylidene Fluo- ride （PVDF） Ultrafiltration （UF） membranes with the results from the experiment that applied the Response Sur- face Method （RSM） and Central Composite Design （CCD）. The factors considered in the experimental design were sodium hydroxide （NaOH） concentration, sodium bypochlorite concentration （NaCIO）, citric acid concentration and cleaning duration, The interactions between the factors were investigated with the numerical model. Humic acid （20 mg· L-1） was used as the model foulant, and chemical enhanced backflush （CEB） was employed to sim- ulate the chemical cleaning process. The concentrations of sodium hydroxide, sodium hypochlorite, citric acid and cleaning duration tested during the experiments were in the range of 0.1%-0.3% 100-300 mg· L-1 1%-3% and 0.5-1.5 h, respectively. Among the variables, the sodium hypochlorite concentration and the cleaning dura- tion showed a positive relationship involving the increased efficiency of the chemical cleaning. The chemical cleaning efficiency was hardly improved with increasing concentrations of sodium hydroxide. However, the data was sharply decreased when at a low level of sodium hydroxide concentration. In total, 54 sets of cleaning schemes with 80% to 100K cleaning efficiency were observed with the R＆M model after calibration.