Detection of Partial and Extended Blockages: A Case Study of Edible Oil Pipeline System

This work focuses on the development and implementation of a simulation-based approach for the detection of partial and extended blockages within an edible oil pipeline system. Blockages, whether partial or extended, pose a significant operational and safety risks. This study employs computational fluid dynamics (CFD) simulations to model the flow behaviour of edible oil through pipeline under varying conditions. It leverages advanced computational fluid dynamics (CFD) simulations to analyze pressure, velocity, and temperature variations along the pipeline. By simulating scenarios with different blockage characteristics, there is establishment of distinctive patterns indicative of partial and extended obstructions. Through extensive analysis of simulation data, sensing element, and monitoring system, processing signal input and response output, the system can accurately pinpoint the location and severity of blockages, providing crucial insights for timely intervention. The detection system represents a significant advancement in pipeline monitoring technology, offering a proactive and accurate approach to identify blockages and mitigate potential risks and ensure the uninterrupted flow of edible oil, thereby enabling timely intervention and maintenance.

Debris Fan Produced by Failure of Canyon-Blocking Pyroclastic Flows

Ash-rich pyroclastic flows from the cataclysmic eruption of Mount Mazama (~7700 yr. B. P.), Cascade volcanic arc, Oregon, entered and blocked the narrow, bedrock-lined canyon of the Williamson River approximately 35 to 44 km from the source volcano. The blockage impounded a body of water which then released producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boulder core comprised of locally sourced bedrock boulders and three sand-rich units including a fine-grained sand unit, a sandy pumice gravel (±basalt/hydrovolcanic tuff) unit, and a pumice pebble-bearing, crystal-rich sand unit. Hand-drilled auger holes up to ~1.6 m deep were used to obtain samples of the sand-rich units. Units were delimited using surface and down-hole observations, composition and texture, estimated density, statistical parameters of grain size, and vertical and lateral distribution of properties. Overtopping followed by rapid incision into the ash-rich pyroclastic flows progressively cleared the canyon, but a bedrock knickpoint near the head of the canyon limited the volume of debris available for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boulders and lithic-rich sand was followed by rapid deposition with minimal reworking of remobilized pyroclastics. Continued draining of the impounded lake sent hyperconcentrated flows onto the debris fan depositing pumice-rich gravels that graded upward to crystal-rich sands.

Hydrate Prevention Strategies and the Associated Cost in the Gulf of Mexico

With the petroleum industry endeavoring to develop promising oil and gas in deeper water, gas hydrates prevention is a serious concern for oil and gas producing companies producing at conditions in the hydrate region. This paper details lessons learned from the successful field deployment of AA LDHI and proper implementation strategies used for 3 different practical fields as case studies in the Gulf of Mexico. From the 3 field experiences, the AA LDHI has been used to replace the conventional thermodynamic hydrate inhibitor due to its numerous benefits during steady state operations and transition operations where AA LDHI is injected prior to extended shut in and restart for fields producing at low water cut. However, the strategy to develop a cost effective chemical management of hydrates for fields producing at high water cut is by pumping methanol or diesel to push down the wellbore fluid below the mud line during planned and unplanned shut-ins to delay water production, it also secures the riser with non hydrate fluids. This illustrates how the AA LDHIs are used in conjunction with more conventional hydrate management approaches to reach an optimal cost effective field hydrate management solution. However, this shows that the key to overall success of hydrate prevention is a full integration of a good front end design, a comprehensive deployment and an effective down hole monitoring system.

Blockage of the Deep-Sea Mining Pump Transporting Large Particles with Different Sphericity

The present study aims to plumb blockage of the deep-sea mining pump transporting large particles with different shapes. A numerical work was performed through combining the computational fluid dynamics(CFD) technique and the discrete element method(DEM). Six particle shapes with sphericity ranging from 0.67 to 1.0 were selected. A velocity triangle is built with the absolute, relative, and circumferential velocities of particles. Velocity triangles with absolute velocity angles ranging from 90° to 180° prevail in the first-stage impeller. With declining sphericity, more particles follow the velocity triangle with absolute velocity angles ranging from 0° to 90°, which weakens the ability of particles to pass through the flow passage. Furthermore, the forces acting on the particles traveling in the impeller passage are analyzed. Large particles, especially non-spherical ones, suffer from high centrifugal force and therefore move along the suction surface of the impeller blades. Non-spherical particles undergo great drag force as a result of large surface area. The distribution of drag force angles is featured by two peaks, and one vanishes due to blockage.As particle sphericity declines, both magnitude and angle of the pressure gradient force decrease. Variation of the drag force and the pressure gradient force causes clockwise deflection of the centripetal force, resulting in deflection and elongation of particle trajectory, which increases the possibility of blockage.

Experimental study on the mechanism of flow blockage formation in fast reactor

Various sources of solid particles might exist in the coolant flow of a liquid metal cooled fast reactor(e.g.,through chemical interaction between the coolant and impurities,air,or water,through corrosion of structural materials,or from damaged/molten fuel).Such particles may cause flow blockage accidents in a fuel assembly,resulting in a reduction in coolant flow,which potentially causes a local temperature rise in the fuel cladding,cladding failure,and fuel melt.To understand the blockage formation mechanism,in this study,a series of simulated experiments was conducted by releasing different solid particles from a release device into a reducer pipe using gravity.Through detailed analyses,the influence of various experimental parameters(e.g.,particle diameter,capacity,shape,and static friction coefficient,and the diameter and height of the particle release nozzle)on the blockage characteristics(i.e.,blockage probability and position)was examined.Under the current range of experimental conditions,the blockage was significantly influenced by the aforementioned parameters.The ratio between the particle diameter and outlet size of the reducer pipe might be one of the determining factors governing the occurrence of blockage.Specifically,increasing the ratio enhanced blockage(i.e.,larger probability and higher position within the reducer pipe).Increasing the particle size,particle capacity,particle static friction coefficient,and particle release nozzle diameter led to a rise in the blockage probability;however,increasing the particle release nozzle height had a downward influence on the blockage probability.Finally,blockage was more likely to occur in non-spherical particles case than that of spherical particles.This study provides a large experimental database to promote an understanding of the flow blockage mechanism and improve the validation process of fast reactor safety analysis codes.

Detecting the backfill pipeline blockage and leakage through an LSTM-based deep learning model

Detecting a pipeline's abnormal status,which is typically a blockage and leakage accident,is important for the continuity and safety of mine backfill.The pipeline system for gravity-transport high-density backfill(GHB)is complex.Specifically designed,efficient,and accurate abnormal pipeline detection methods for GHB are rare.This work presents a long short-term memory-based deep learning(LSTM-DL)model for GHB pipeline blockage and leakage diagnosis.First,an industrial pipeline monitoring system was introduced using pressure and flow sensors.Second,blockage and leakage field experiments were designed to solve the problem of negative sample deficiency.The pipeline's statistical characteristics with different working statuses were analyzed to show their complexity.Third,the architecture of the LSTM-DL model was elaborated on and evaluated.Finally,the LSTM-DL model was compared with state-of-the-art(SOTA)learning algorithms.The results show that the backfilling cycle comprises multiple working phases and is intermittent.Although pressure and flow signals fluctuate stably in a normal cycle,their values are diverse in different cycles.Plugging causes a sudden change in interval signal features;leakage results in long variation duration and a wide fluctuation range.Among the SOTA models,the LSTM-DL model has the highest detection accuracy of98.31%for all states and the lowest misjudgment or false positive rate of 3.21%for blockage and leakage states.The proposed model can accurately recognize various pipeline statuses of complex GHB systems.

Development and Research of Non⁃Stirring Conveying Device for Waste Resin in Nuclear Power Plant

Blockage in the storage and transportation of waste resin is a difficult problem in the radioactive waste treatment process of nuclear power plants.In this study,in order to solve the problems of unstable resin transport concentration and easy blockage of conveying equipment and pipelines in nuclear power plants in China,a set of non⁃stirring conveying devices is developed,and theoretical calculations,simulation analysis and experimental verification are carried out.By transporting resin using the no stirring conveying device developed in this paper,it is not only to eliminate the risk of blockage and ensure the safety of transportation,but also to adjust the concentration of conveying resin to change the transport efficiency according to the operating conditions.The effective bearing rate of waste resin storage tank can be improved,so that the comprehensive performance of waste resin storage and transportation in nuclear power plants can be greatly improved.

Study of asphaltene dispersion and removal for high-asphaltene oil wells

Many wellbores are blocked by asphaltene deposits,which lead to production problems in the oilfield development process.In this paper,methods such as elemental analysis,and solvent extraction are adopted for the study of wellbore blockages.The content of organic matter in blockages is higher than 96% and asphaltene is the main component of the organic matter with n-heptane asphaltene content of 38%.Based on the above analyses,an agent for asphaltene dispersion and removal（named as SDJ） was developed.The performance of the SDJ agent was evaluated,and it was found that the dissolution rate of asphaltene can reach 2.9 mg.mL-1.min-1 at 60 oC.SDJ agent（1wt%） was added to crude oil with a colloid instability index greater than 0.9 can effectively inhibit asphaltene deposition in the wellbore.By the viscosity method,the dissolution amount of SDJ agent was calculated,and it was found that when the viscosity of the system is around 2,000 mPa.s（the common viscosity of crude oil）,the amount of SDJ agent added to the blockage was at least 96 g per 100 g blockages.Therefore,SDJ agent has promising application for dispersion and removal of asphaltene deposition in high-asphaltene wells.

Smart Sewers 1: Sewer Configuration at Rural Houses

The layout of houses and other buildings impacts the way in which foul sewer pipework is positioned internally and externally. Less water to waste through conservation measures reduces the distance that gross solids transfer in sewers and increases the number of sewer blockages. Dwelling houses are often laid out where the solids from faecal flushes are at the head of the sewer line with other flows entering downstream. Discharges from appliances such as washing machines, dishwashers, baths, showers and kitchen/utility sinks are often not utilised in the transfer of the gross solids when they enter downstream of the faecal flushes. At present, no recommendations or specific design guidance exist regarding the design of internal building layouts relating to sewer configuration requirements. Furthermore, to date, no specific research exists which examines pipeline configuration scenarios outside buildings in terms of the link between multiple grey water discharge points and solid transfer in a sewer system. The aim of this study was to investigate sewer layout at houses in terms of maximising greywater flow in relation to solid transfer. This study showed that smart sewers are needed which utilise all the foul water leaving a building as it was found that up to 100% of greywater in some instances is completely missed out in terms of solid transfer. Consequently, optimal sewer design is far from being realised and internal building layouts should be designed with consideration of the faecal flushes and greywater flows.

Solid Transfer in Low Flow Sewers, the Distance Travelled So Far Is Not Enough

Sewer blockages are on the increase whilst water closet (WC) flush volumes are on the decrease. Furthermore, Water UK reported figures show that the actual number of properties affected by sewer flooding is on the rise. Sewer blockages can lead to sewer flooding of homes and collapse of sewers which impact negatively on social, economic and environmental factors, and therefore, they are not sustainable. Water conservation is required due to water stress but reduced water use results in less water to waste, which in turn reduces solids’ transfer in sewers. When considering reducing water usage through water conservation, these savings could be cancelled out by an increased population and the situation exacerbated by the impacts of climate change. There are issues in relation to varying design methods, a reliance on engineering judgement in sewer design, uncertainty relating to future water stress, and a lack of cross disciplinary design decision-making. Public health engineering solutions are needed to reduce the number of sewer blockages and the environmental impact of sewer flooding. This paper examines the fundamental research that have been carried out in the area of “solid transfer in sewers” resulting from “less water to waste” since the mid-20th Century. Contrary to existing literature, this paper identifies that, now more than ever, this type of research is needed to deal with the increased need for water conservation. To judge that solid transfer research is complete can be compared to supporting a statement that “water conservation is complete”.

Review on application of nanoparticles for EOR purposes: A critical review of the opportunities and challenges

Nanoparticles have already gained attentions for their countless potential applications in enhanced oil recovery.Nano-sized particles would help to recover trapped oil by several mechanisms including interfacial tension reduction, impulsive emulsion formation and wettability alteration of porous media. The presence of dispersed nanoparticles in injected fluids would enhance the recovery process through their movement towards oil–water interface. This would cause the interfacial tension to be reduced. In this research, the effects of different types of nanoparticles and different nanoparticle concentrations on EOR processes were investigated. Different flooding experiments were investigated to reveal enhancing oil recovery mechanisms. The results showed that nanoparticles have the ability to reduce the IFT as well as contact angle, making the solid surface to more water wet. As nanoparticle concentration increases more trapped oil was produced mainly due to wettability alteration to water wet and IFT reduction. However, pore blockage was also observed due to adsorption of nanoparticles, a phenomenon which caused the injection pressure to increase. Nonetheless, such higher injection pressure could displace some trapped oil in the small pore channels out of the model. The investigated results gave a clear indication that the EOR potential of nanoparticle fluid is significant.

A study of hydrate plug formation in a subsea natural gas pipeline using a novel high-pressure flow loop

The natural gas pipeline from Platform QKI8-1 in the southwest of Bohai Bay to the onshore processing facility is a subsea wet gas pipeline exposed to high pressure and low temperature for a long distance. Blockages in the pipeline occur occasionally. To maintain the natural gas flow in the pipeline, we proposed a method for analyzing blockages and ascribed them to the hydrate formation and agglomeration. A new high-pressure flow loop was developed to investigate hydrate plug formation and hydrate particle size, using a mixture of diesel oil, water, and natural gas as experimental fluids. The influences of pressure and initial flow rate were also studied. Experimental results indicated that when the flow rate was below 850 kg/h, gas hydrates would form and then plug the pipeline, even at a low water content （10%） of a water/oil emulsion. Furthermore, some practical suggestions were made for daily management of the subsea pipeline.

Interactions between the fluid and an isolation tool in a pipe:laboratory experiments and numerical simulation

A remote-control tether-less isolation tool is a mechanical device that is normally used in pipelines to block the flow at a given position by transforming a blocking module. In this study, the interactions between the fluid and the plug module of the isolation tool were investigated. Simulations of the plug process and particle image velocimetry measurements were performed to study the flow characteristics. Numerical solutions for the continuity, momentum, and energy equations were obtained by using commercial software based on finite-volume techniques. Box–Behnken design was applied, and response surface methodology（RSM）-based CFD simulation analysis was conducted. The dynamic model in the plug process was built by RSM and used to evaluate the influences of the main mechanical parameters on the pressure during the plug process. The diameter of the isolation tool and the diameter of the plug module have strong influences on the process, and the length of the isolation tool has only a little influence on the plug process.

Effects of loose deposits on debris flow processes in the Aizi Valley, southwest China

Loose deposits, rainfall and topography are three key factors that triggering debris flows.However, few studies have investigated the effects of loose deposits on the whole debris flow process.On June 28, 2012, a catastrophic debris flow occurred in the Aizi Valley, resulting in 40 deaths.The Aizi Valley is located in the Lower Jinsha River,southwestern Sichuan Province, China. The Aizi Valley debris flow has been selected as a case for addressing loose deposits effects on the whole debris flow process through remote sensing, field investigation and field experiments. Remote sensing interpretation and laboratory experiments were used to obtain the distribution and characteristics of the loose deposits, respectively. A field experiment was conducted to explore the mechanics of slope debris flows, and another field investigation was conducted to obtain the processes of debris flow formation, movement and amplification. The results showed that loose deposits preparation, slope debris flow initiation,gully debris flow confluence and valley debris flow amplification were dominated by the loose deposits.Antecedent droughts and earthquake activities may have increased the potential for loose soil sources in the Aizi Valley, which laid the foundation for debris flow formation. Slope debris flow initiated under rainfall, and the increase in the water content as well as the pore water pressure of the loose deposits were the key factors affecting slope failure. The nine gully debris flows converged in the valley, and the peak discharge was amplified 3.3 times due to a blockage and outburst caused by a large boulder. The results may help in predicting and assessing regional debris flows in dry-hot and seismic-prone areas based on loose deposits, especially considering large boulders.

Partial flow blockage analysis of the hottest fuel assembly in SNCLFR-100 reactor core

In this paper, we perform an unprotected partial flow blockage analysis of the hottest fuel assembly in the core of the SNCLFR-100 reactor, a 100 MW_(th) modular natural circulation lead-cooled fast reactor, developed by University of Science and Technology of China. The flow blockage shall cause a degradation of the heat transfer between the fuel assembly and the coolant potentially,which can eventually result in the clad fusion. An analysis of core blockage accidents in a single assembly is of great significance for LFR. Such scenarios are investigated by using the best estimation code RELAP5. Reactivity feedback and axial power profile are considered. The crosssectional fraction of blockage, axial position of blockage,and blockage-developing time are discussed. The cladding material failure shall be the biggest challenge and shall be a considerable threat for integrity of the fuel assembly if the cross-sectional fraction of blockage is over 94%. The blockage-developing time only affects the accident progress. The consequence will be more serious if the axial position of a sudden blockage is closer to the core outlet.The method of analysis procedure can also be applied to analyze similar transient behaviors of other fuel-type reactors.

Aerodynamic Design of a Subsonic Evacuated Tube Train System

The so-called Evacuated Tube Train(ETT)is currently being proposed as a high-speed transportation system potentially competitive with airplane transportation.Aerodynamic resistance is one of the most crucial factors for the successful design of an ETT.In the present work,a three-dimensional concept ETT model has been elaborated.The aerodynamic characteristics of the subsonic ETT have been numerically simulated under different conditions.The train’s running speed varies from 600 km/h up to 1200 km/h,and the blockage ratio is in the range between 0.1 and 0.3.As the blocking ratio and running speed increase,the resistance of the head car increases greatly,while the resistance of the middle car changes slightly.The aerodynamic resistance of the tail car is affected by the shock wave emerging in the wake flow.Two different design criteria for the maximum allowed aerodynamic resistance are proposed for aerodynamic parameter matching.With an increase in the blockage ratio and running speed,the atmospheric pressure in the tube should be decreased to achieve a balance.

Formation blockage risk analysis of geothermal water reinjection:Rock property analysis,pumping and reinjection tests,and long-term reinjection prediction

The blockage induced by particle migration and deposition is one of the main reasons for the decrease of reinjection capacity in the porous geothermal reservoir with a low and medium temperature.In this paper,a new drilled geothermal well in Xining basin China is taken as an example to investigate the formation blockage risk due to the movable clay and sand particles in pores.The physical properties of the reservoir rocks were analyzed,a series of pumping and reinjection tests were conducted,and the longterm reinjection performance of the well was predicted by numerical simulation based on the test fitting.The results show that the geothermal reservoir rocks are argillaceous and weakly cemented sandstones with a content of movable clay and sand particles up to 0.18–23.42 wt.%.The well presented a high productivity of 935–2186 m3?d-1 at a pressure difference of 0.7–1.62 MPa in the pumping tests associated with a large amount of clay and sand particles produced out,while in the reinjection test,only a low injectivity of 240–480 m3?d-1 was observed at an injection pressure of 0.2–0.6 MPa with the clay and sand particles near the wellbore move into deep.According to the prediction,under conditions of a blockage risk,the injectivity of the well will start to decline after 100 days of injection,and in the third year,it will decrease by 59.00%–77.09%.The influence of invasion of pretreated suspended particles and scale particles can be neglected.Under conditions of a high blockage risk,the injectivity of the well will decrease significantly in the first 20–30 days,with a decline of 75.39%–78.96%.Generally,the higher the injection pressure or rate,the greater the decrease in injectivity of the well caused by particle blockage.Pump lifting is an effective measure to remove the well blockage which can be used regularly.

Effect of a synthesized anionic fluorinated surfactant on wettability alteration for chemical treatment of near-wellbore zone in carbonate gas condensate reservoirs

The pressure drop during production in the near-wellbore zone of gas condensate reservoirs causes condensate formation in this area.Condensate blockage in this area causes an additional pressure drop that weakens the effective parameters of production,such as permeability.Reservoir rock wettability alteration to gas-wet through chemical treatment is one of the solutions to produce these condensates and eliminate condensate blockage in the area.In this study,an anionic fluorinated surfactant was synthesized and used for chemical treatment and carbonate rock wettability alteration.The synthesized surfactant was characterized by Fourier transform infrared spectroscopy and thermogravimetric analysis.Then,using surface tension tests,its critical micelle concentration(CMC)was determined.Contact angle experiments on chemically treated sections with surfactant solutions and spontaneous imbibition were performed to investigate the wettability alteration.Surfactant adsorption on porous media was calculated using flooding.Finally,the surfactant foamability was investigated using a Ross-Miles foam generator.According to the results,the synthesized surfactant has suitable thermal stability for use in gas condensate reservoirs.A CMC of 3500 ppm was obtained for the surfactant based on the surface tension experiments.Contact angle experiments show the ability of the surfactant to chemical treatment and wettability alteration of carbonate rocks to gas-wet so that at the constant concentration of CMC and at 373 K,the contact angles at treatment times of 30,60,120 and 240 min were obtained 87.94°,93.50°,99.79°and 106.03°,respectively.However,this ability varies at different surfactant concentrations and temperatures.The foamability test also shows the suitable stability of the foam generated by the surfactant,and a foam half-life time of 13 min was obtained for the surfactant at CMC.

Development of a subchannel code for blockage accidents of LMFRs based on the 3D fuel rod model

To predict the thermal-hydraulic(T/H)parameters of the reactor core for liquid-metal-cooled fast reactors(LMFRs),especially under flow blockage accidents,we developed a subchannel code called KMC-FB.This code uses a time-dependent,four-equation,singlephase flow model together with a 3D heat conduction model for the fuel rods,which is solved by numerical methods based on the finite difference method with a staggered mesh.Owing to the local effect of the blockage on the flow field,low axial flow,increased forced crossflow,and backflow occur.To more accurately simulate this problem,we implemented a robust and novel solution method.We verified the code with a low-flow(~0.01 m/s)and large-scale blockage case.For the preliminary validation,we compared our results with the experimental data of the NACIE-UP BFPS blockage test and the KIT19ROD blockage test.The results revealed that KMC-FB has sufficient solution accuracy and can be used in future flow blockage analyses for LMFRs.

Numerical simulation and analysis of aerodynamic drag on a subsonic train in evacuated tube transportation

The aerodynamic drag on a train running in an evacuated tube varies with tube air pressure, train speed and shape, as well as blockage ratio. This paper uses numerical simulations to study the effects of different factors on the aerodynamic drag of a train running at subsonic speed in an evacuated tube. Firstly, we present the assumption of a steady state, two dimensional, incompressible viscous flow with lubricity wall conditions. Subsequently, based on the Navier-Stokes equation and the k-c turbulent models, we calculate the aerodynamic drag imposed on the column train with a 3-meter diameter running under different pressure and blockage ratio conditions in an evacuated tube transporta- tion （ETT） system. The simulation is performed with FLUENT 6.3 software package. An analyses of the simulation re- sults suggest that the blockage ratio for ETT should be in the range of 0.25-0.7, and the tube internal diameter in the range of 2-4 m, with the feasible vacuum pressure in the range of 1-10 000 Pa for the future subsonic ETT trains.