Discharge Pipeline Research Articles

Innovative Electrochemical Nano-Robot: Integrating Printed Nanoelectronics with a Remote-Controlled Robotic for On-Site Underwater Electroanalysis.

Smart and remote sensing technologies offer significant advantages across various applications. This study introduces an innovative approach integrating printed electrochemical nanosensors with a remotely controllable underwater robot, creating a "Robo-sensor" for underwater and surface water sensing. Unlike conventional underwater sensors, the Robo-sensor operates in three dimensions, both on the surface and underwater, targeting specific locations such as coastal areas and deep-sea environments while transmitting data to an external analytical unit. To achieve this, we developed a conductive nanoink by combining graphite, silver nanorods (AgNRs; diameter: 30 ± 20 nm, length: 2 ± 0.2 μm), nail polish as a cohesive agent, and an organic solvent. This ink was used to fabricate an electroanalytical system on the mini-robot's body. The Robo-sensor, connected to a portable potentiostat, demonstrated linear responses to hydroquinone (HQ) and nitrite ions, with detection ranges of 5.0-1356.0 and 3.0-1200.0 μM, respectively, under artificial seawater conditions (High salinity). Its repeatability (RSD <6%), stability (up to 40 continuous applications with an error < ± 10%), and sensitivity were thoroughly evaluated. The Robo-sensor's practical applications included detecting chemical leaks in underwater pipelines containing HQ, a hazardous chemical relevant to coastal industries such as petrochemicals. Additionally, it analyzed surface water contaminated with NO2- near and far from a wastewater discharge pipeline, providing valuable insights for environmental and ecosystem investigations. In conclusion, the developed Robo-sensor enables on-site analysis both on the surface and underwater, reducing time, costs, and risks in high-hazard environments like deep waters. With further modifications, this strategy could be adapted for diverse applications, including offshore oil and petrochemical operations, corrosion studies, and underwater environmental monitoring, thus expanding the real-world impact of electrochemical science.

Analyses of gas pulsation characteristics in the discharge pipeline of a hyper compressor

For the analysis of gas pulsation characteristics in the pipeline systems of low density polyethylene (LDPE) hyper compressors, a time-domain calculation method for compressor pipeline gas pulsation based on real gas properties is proposed. First the thermophysical property tables are prepared with gas state parameters as independent and dependent variables. Then one-dimensional unsteady flow equations and characteristic equations for pipeline flow are established based on real gas properties. After setting pipeline parameters and boundary conditions, the flow equations are discretized using a two-step method at the inner points of the pipeline. The characteristic equations are discretized using the trapezoidal integration method at the boundary points. Thus, the time-domain solving of pulsating flow field in the pipeline is realized. A self-developed numerical code was used to conduct the time-domain calculation and analysis of gas pulsation in the discharge pipeline of a two-stage hyper compressor. The calculated pressure pulsation curves based on real gas properties are in good agreement with experimental data, with a maximum difference lower than 4% of the local average pressure, which is smaller than the difference between the results calculated based on the plane wave theory and the measured data. The analysis of gas pulsation characteristics shows that the pressure pulsation in the main pipeline is mainly contributed by the fundamental and second harmonics. The pressure pulsation in the safety valve branch is higher than that in the main pipeline, and the harmonic components falling into the acoustic resonance frequency range of this branch have significant amplitudes. The acoustic resonance frequency of the branch pipeline is not affected by the main pipeline. Pressure pulsation varies with changes in rotational speed and back pressure, and the pulsation level is more significantly affected by rotational speed compared to back pressure. The renovation scheme of connecting the safety valve branch and expansion tube in series can effectively reduce the pressure pulsation levels of the main pipeline and branch pipeline.

ГИДРАВЛИЧЕСКИЙ РАСЧЕТ ТРУБОПРОВОДА С РАССРЕДОТОЧЕННЫМ СБРОСОМ РАССОЛА В АКВАТОРИЮ

When producing water using desalination technologies, significant volumes of highly concentrated brines are formed. The solution of the problem of wastes recycling is an important global issue for water protection organizations, and the studies of the last decade confirm this. The article discusses an environmentally friendly method of dispersed uniform brine discharge into the water area, presents the developed technical solution and describes the principle of its operation. As an example, the authors calculate the hole diameters of the distribution pipeline for uniform brine discharge along the length. We calculated the radius and the scattering jet rate at a given distance from the hole in the distribution pipeline. The difference in brine salt concentrations at a depth of 20 m from the discharge point between the background concentration in the sea and the salt concentration was found to be from 0.439 % to 0.524 % along the length of the discharge pipeline. Dissolution of brines to safe concentrations becomes even more intense in the presence of sea currents. The research results can be used in the design and operation of such systems.

Numerical simulation of water-slag elbow erosion-inhibiting by regulating the slag injection position with a novel preceding rotating sheet structure

The elbow erosion seriously jeopardizes the safe and stable operation of water–slag discharge pipeline of the coal gasification system. This work simulated water–slag elbow characteristics with various slag injection positions by simulating five simplified and representative erosion categories, including A-type horizontal-vertical elbow with an upstream flow, B-type horizontal-vertical elbow with a downstream flow, C-type vertical-horizontal elbow with an upstream flow, D-type vertical-horizontal elbow with a downstream flow and E-type horizontal-horizontal elbow. Compared with the C/D-type elbow, where particles were injected uniformly, the A-type elbow and E-type elbow were found to increase erosion rate, while the B-type elbow decreases erosion rate. An interesting discovery is that the elbow erosion rate is relatively low for small particles when particles are injected from the middle and bottom positions of the inlet section of the elbow. Based on the observation, a novel preceding rotating sheet structure was developed to regulate the particle injection position. It shows an excellent anti-erosion performance by reducing the maximum erosion rate of particles with diameters of 50, 100, and 200 μm by 23%, 35%, and 43%, respectively.

High-temperature Mechanical Analysis of Discharge Pipeline of Pressurizer

The severe accident is the beyond basis design accident due to several initial faults. The discharge pipeline of pressurizer is mainly used for pressure relief and evacuation of hydrogen in the primary circuit in severe accident. It can reduce the possibility of high-pressure core melt and the explosion of hydrogen. But in severe accident, the highest temperature of gas in the pipeline can reach 1200℃, which far exceeds the design temperature of pressurized water reactor. So it may cause the buckling or rupture of the pipeline. The pipeline may loss its discharge function. In this passage, we study the resistance of the discharge pipeline to high temperature in severe accident from the aspects of severe accident situation, high-temperature mechanical properties of pipeline material, the temperature field and stress of the pipeline, the evaluation of the stress and so on. In order to demonstrate the function of a certain nuclear power plant discharge pipeline, RCC-MR which is suitable for the high-temperature evaluation, is choose to evaluate the stress, the creep and the buckling of the pipeline. The results of the evaluation show that the discharge pipeline in this nuclear power plant can meet the functional requirements in the severe accidents.

Experimental test-bed for test of pumps with frequency regulation

A literature review was conducted to develop an experimental stand for testing pumps. It was established that frequency regulation is one of the quantitative energy-saving methods of controlling the operation of the pumping unit. At the same time, the influence on the pump unit is carried out by changing the operating point by means of variable pump curve. The hydraulic schemes for experimental study of frequency-controlled pumps presented in the article have certain disadvantages: 1) the location of the pump relative to the tank is ambiguous regarding the operation of the pump under flooded suсtion; 2) pressure regulation is provided only in the direction of its decrease; 3) refers rather to the automation of pumping installations. On the designed and manufactured experimental stand, it is possible to study the operation of the pump with the use of a frequency converter and without it, through a bypass line. When testing the pump for systems that operate according to the fluid level in the suction tank, use either a valve on the discharge pipeline (with the use of a frequency converter) or a ball valve on the discharge pipeline from the discharge tank (without the use of a frequency converter). In addition, pump testing using a frequency converter can be performed for pressure-operated systems. The installed frequency converter is a regulator of the flow of the working fluid, which allows adjusting of the pump discherge. The pump designed on the experimental stand is a self-suction jet that does not need to be installed under flooded suсtion. The discharge tank is located higher than the suction tank, which ensures the circulation of the working fluid by gravity. The working fluid will be water. The preliminary results, performed on the experimental stand, confirm the possibility of frequency regulation of the pump using a frequency converter.

The potential role of biofilms in promoting fouling formation in radioactive discharge pipelines

Nuclear facility discharge pipelines accumulate inorganic and microbial fouling and radioactive contamination, however, research investigating the mechanisms that lead to their accumulation is limited. Using the Sellafield discharge pipeline as a model system, this study utilised modified Robbins devices to investigate the potential interplay between inorganic and biological processes in supporting fouling formation and radionuclide uptake. Initial experiments showed polyelectrolytes (present in pipeline effluents), had minimal effects on fouling formation. Biofilms were, however, found to be the key component promoting fouling, leading to increased uptake of inorganic particulates and metal contaminants (Cs, Sr, Co, Eu and Ru) compared to a non-biofilm control system. Biologically-mediated uptake mechanisms were implicated in Co and Ru accumulation, with a potential bioreduced Ru species identified on the biofilm system. This research emphasised the key role of biofilms in promoting fouling in discharge pipelines, advocating for the use of biocide treatments methods.

Slurry Discharge Pipeline Damage and Wear Due to Transporting Rock Particles during Slurry Shield Tunneling: A Case Study Based on In Situ Observed Results

Rock particles in excavated materials can damage and wear down slurry discharge pipelines when slurry shield tunneling occurs in a pebble layer and rock ground. This pipeline damage and wear, if not properly dealt with, can lead to a broken-down tunneling machine. Based on a slurry shield tunneling project in China, damage and wear were thoroughly examined. The observed pipeline wear and leaks, transported rock particles, mechanical properties, and flow rate of the carrier slurry were presented. The measured results showed that the wear rates of a straight pipe, a pipe along a curved tunnel, a 60° inclined pipe, and a 90° elbow pipe in pebble ground were approximately 0.71 mm/100 rings, 1 mm/100 rings, 2.14 mm/100 rings, and 4 mm/100 rings, respectively. When the machine drove into rock ground, the wear rates increased by one to two times, which could be attributed to the sharper particle shapes. Countermeasures to address these issues, such as adjusting the pipeline layout, welding reinforcement plates in advance, and preparing additional pipes, were highlighted. The wear rates of different types of pipes, the effectiveness of new pipeline fixing methods, and the probability of pipeline leaks in different strata were discussed in detail.

Numerical study on critical flow velocity of ice slurry in the pipe of ice source heat pump system

The traditional evaporator of water source heat pump system is easy to freeze when the water source temperature is too low in winter. A novel ice source heat pump system is proposed, which can use low temperature surface water to supply heat to buildings. One of the key problems for safe transportation is velocity range of ice slurry in ice outlet pipeline. In order to study the critical flow velocity of ice slurry in the pipe, an Euler model of horizontal straight pipe and 90° elbow pipe were established by Fluent software. The influence of five factors on the critical flow velocity of two kinds of pipes, including initial ice packing fraction, ice particle size, pipe diameter, length of straight pipe and radius curvature of elbow was studied. It found that the initial ice content should be controlled from 10% to 15%. The inlet flow rate was 20% higher than the critical flow rate under the most unfavorable condition. Ice particle size was less than 0.2 mm. The total length of ice discharge pipeline was less than 50 m. Curvature radius of the bend should be met the minimum requirements of the specification of the pipe used.

Analysis of Flow-induced Vibration Based on Discharge Pipeline on Offshore Platform

Objective: Because of the widespread use of offshore oil production platforms, there is a large amount of pipeline equipment on them. The excitation generated by fluid flow in the pipeline will cause flow-induced vibration of the pipeline and damage the pipeline structure. As a result, researching the flow-induced vibration of the pipeline is critical. Methods: In this paper, the pipeline on an offshore oil production platform in the South China Sea is taken as the research object, and the calculation and analysis of the pipeline section on the platform are focused on. The fluid-structure coupling method is used to calculate and analyze the pipeline section, and the flow-induced vibration of the pipeline is simulated. Results: Through calculation and analysis, the results show that the vibration speed of the pipeline in its original state exceeds the specified range. To reduce the degree of vibration, the pipeline constraint is redesigned and flow-induced vibration analysis is conducted. The results show that the vibration level meets the requirements. Conclusion: The flow-induced vibration of offshore pipelines is mainly caused by the uneven distribution of pressure in the pipelines caused by gas-liquid two-phase flow in the pipelines, and the reasonable setting of pipeline constraints can effectively reduce the degree of pipeline vibration.

Techno-economic evaluation of buffered accelerated weathering of limestone as a CO2 capture and storage option

Carbon dioxide storage technologies are needed not only to store the carbon captured in the emissions of hard-to-abate sectors but also for some carbon dioxide removal technologies requiring a final and permanent storage of CO2. The pace and scale of geological CO2 storage deployment have fallen short of expectations, and there is a growing interest in ocean-based CO2 storage options. As complementary to geological storage, buffered accelerated weathering of limestone (BAWL) has been proposed to produce a buffered ionic solution at seawater pH, derived from the reaction in seawater between a CO2 stream and a micron-sized powder of calcium carbonate (CaCO3), within a long tubular reactor. The addition of calcium hydroxide to buffer the unreacted CO2 before the discharge in seawater is also envisaged. BAWL avoids the risks of CO2 degassing back into the atmosphere and does not induce seawater acidification. This work presents a mass and energy balance and preliminary cost analysis of the technology for different configurations of discharge depth (100, 500, 3,000 m), pipeline length (10, 25, 100 km) and diameter of CaCO3 particles (1, 2, 10 µm) fed in the tubular reactor. The total energy consumption to capture and store 1 t of CO2 generated by a steam-methane reforming (SMR) process ranges from 1.3 to 2.2 MWh. The CO2 released from the CaCO3 calcination to produce the buffering solution leads to a total CO2 storage requirement 43–85% higher than the CO2 derived by SMR. The total cost to capture and store 1 t of CO2 from SMR is estimated in the range 142–189 €.

Linkage of pipeline blockage to coagulation-flocculation process: effect of anionic polymer and pH

This study investigated the frequent blockages observed in the discharge pipeline in the chemical mechanical polishing wastewater treatment plant. Preliminary analyses indicated that blockages were predominantly consisted of residual organically-bounded Al due to overdosage of polyaluminum chloride (PACl) and anionic polymer during coagulation-flocculation process. To minimize the recurrence of blockage, jar test experiments were conducted in this study to identify optimum dosages of PACl and anionic polymer as well as optimum pH value. According to the model derived from jar tests, the optimum PACl dosage was dependent on the soluble Cu concentration of wastewater with low initial turbidity [< 1000 nephelometry turbidity units (NTU)]. The PACl dosage would require more than 5 mg L−1 when soluble copper below 20 mg L−1, while PACl is not necessary when more than 20 mg L−1 of soluble copper in the wastewater. On the other hand, optimal PACl dosage was dependent on the initial turbidity of wastewater with high initial turbidity (> 1000 NTU), while the optimal PACl dosage was 30 mg L−1 when initial turbidity around 7000 NTU. The change of pH in the range of 8 to 9.5 did not significantly affect the turbidity or Cu removal, however, higher pH increased the deposition of residual monomeric Al species which might lead to blockage. In summary, controlling PACl dosage at optimum dosage under the conditions of pH 8.5 ± 0.5 and 1 mg L−1 polymer could reduce the blockage occurrence as well as maintain the effluent quality to meet the standards.

Hydrological Considerations for Sizing of a Barge Discharge Pipeline Runway

A key element for water supply systems is the design of the water intake components. Mobile floating platforms (barges) are helpful when the hydraulic system displays substantial variations in water levels. This study presents the hydrological considerations that should be considered for the design of the barge’s pipeline runway. The analysis takes into consideration the maximum and minimum water levels measured at the location. The study was carried out at the Magdalena River -Plato (Colombia) station, finding variations in water levels of between 12.3 m and 16.1 m for return periods of 25 and 100 years, respectively. This information is helpful for designers and consultants in order to design an appropriate barge pipeline runway.

How do discharge rate and pipeline length influence the rheological properties of self-consolidating concrete after pumping?

Pumping changes the rheological properties, workability and construction performance of fresh concrete. However, there were limited knowledges on influences of discharge rates and pumping distances on the fresh properties of concrete. In this paper, effects of various discharge rates and pipeline lengths on rheological properties of self-consolidating concrete (SCC) after pumping were studied. A total of 12 SCC mixtures with the slump flow of 650–745 mm were pumped in pipelines with measured lengths of 342 m, 545 m, and 1044 m by constant discharge rates ranging between 5.1 and 11.4 L/s. Rheological properties were measured before and after pumping. Physical conditions of SCC during pumping, including pressure, shear, and temperature were estimated theoretically and experimentally. Moreover, the total organic carbon in the pore solution of SCC mixtures was measured to evaluate the change of superplasticizer adsorptions after pumping. Test results indicated that, due to pumping, the yield stress increased; the initial tangential viscosity decreased and the shear-thickening phenomenon was eliminated. The changes of yield stresses and viscosity were encouraged by discharge rates. Besides, lower initial slump flow of SCC exhibited a larger slump flow loss after pumping due to a higher shear rate experienced during pumping. The yield stress and viscosity after pumping increased with the increase of pipeline length at similar discharge rates, but decreased with the pipeline length under similar pumping pressures. The adsorption of superplasticizer increased after pumped at relative low discharge rates (5.2–5.7 L/s), but decreased at discharge rates of 7.7–10.8 L/s.

Investigation of interaction between thermodynamic processes and pressure pulsation based on transient CFD model of a reciprocating compressor

This paper presents a transient computational fluid dynamics (CFD) model of a reciprocating compressor to study the interaction of the thermodynamic process and pressure pulsation. To realize the interaction between the thermodynamics and the pressure pulsation, the most difficult procedure lies in dealing with the valve motion and flow through the valve channel both precisely and effectively. Therefore, a discretization method for the flow channel of the ring valve to generate structured grids is proposed. Then, the subsequent model is embedded in the flow channel of the compressor model. User-defined functions are employed to calculate the independent velocity of each valve plate based on the real-time pressure differences across the valve plates. After verified, the influences of the discharge pipeline configuration, pressure ratio, and rotational speed were examined. The results of the numerical model agreed well with the experiment. The maximal deviation between predictions and experiments at the pressure ratio of 3 was 6.14% of indicated power. The maximum deviation increased to 7.42% at the rotational speed of 480 rpm. The results for the discharge pipeline configuration verified that the buffer tank directly following the nozzle of the compressor contributed greatly to attenuating the pressure pulsation. A fast Fourier transform analysis of pressure pulsation showed that at all speeds, the amplitudes were almost the same below the eighth harmonic, and then gradually increased for the higher harmonics.

Simplified Indirect Estimation of Pump Flow Discharge: An Example from Serbia

In the absence of a flowmeter or due to its inaccuracy, the flow rate at the discharge section of the pipeline following the observed pump can be roughly estimated if the pressure can be measured instead. To use the proposed procedure two main conditions should be achieved: (1) a manometer should be installed at the discharge pipeline between the pump and the flow regulation valve, and (2) the actual curve that relates pressure and flow for the observed pump unit should be known in advance. The described example is from Serbia, but it is of interest for any water pumping station with a submersible pump (installed in wells or tanks) where a limited number of adequate places for the measuring of flow are available (if any are available at all), but where the pressure at the discharge pipe of the observed pump can be measured. This simplified method can find applicability in installations in remote rural regions where limited resources are available. The results show that the calculated values of the flow obtained by the presented method deviate greatly in relation to the measured values provided by the portable ultrasonic flowmeter, up to 60% at one of the measuring points. However, in relation to the measured values provided by the permanently installed flowmeter the discrepancy is significantly lower (0.6–6.8%).

Calculation of water hammer on the pressure pipeline of modernized irrigation pumping station

One of the main factors to provide reliable and safe operation of irrigation pump station – prevent possible occurrence of water hammer. In order to determine the magnitude of water hammer’s method of characteristics (moc), wave characteristic method (wcm), graphical analytical and simplified methods of calculations are used. During the design for the construction of the new pump station surge analysis should be carried out using accurate calculation methods moc or wcm using special computer software. At the same time, should the modernization of existing pump station is taking place with the installation of the same equipment, then simplified calculations method can be used. But care must be taken to take in to account all the factors that might increase the risk of occurrence and with the higher magnitude of water hammer: reduced inertia of pumping set’s moving parts, replacement of shutting valves to different types, replacement of air valves to different types, reduction of hydraulic losses after discharge pipeline repair works and etc. Existing simplified calculation methods to calculate water transients in pump stations was modified to take in to account these factors. Based on the proposed method surge analysis calculations had been carried out at modernized pump station “Kizil-tepa”. Comparison of calculation results performed by simplified method and wcm using «KY-Pipe 2018-Surge program-version 9.014» has shown a good similarity in the magnitude of maximal positive pressures.

Evaluation of Pollutant Emissions into the Atmosphere during the Loading of Hydrocarbons in Marine Oil Tankers in the Arctic Region

Emissions of volatile organic compounds into the atmosphere when loading oil or petroleum products into tankers are strong environmental pollutants. Given the increase in oil transport by sea and the development of Arctic routes, humanity faces the task of preserving the Arctic ecosystem. Vapor recovery units can limit the emissions of volatile organic compounds. However, it is necessary to estimate the emissions of oil and petroleum products vapors. This article offers two methods for estimating emissions of volatile organic compounds. In the analytical method, a mathematical model of evaporation dynamics and forecasting tank gas space pressure of the tanker is proposed. The model makes it possible to estimate the throughput capacity of existing gas phase discharge pipeline systems and is also suitable for designing new oil vapor recovery units. Creating an experimental laboratory stand is proposed in the experimental method, and its possible technological scheme is developed.

Исследование процесса разгерметизации нагнетательного трубопровода гидросистемы

Исследование процесса разгерметизации нагнетательного трубопровода гидросистемы

Waste water discharge from a large Ni-Zn open cast mine degrades benthic integrity of Lake Nuasjärvi (Finland)

The Talvivaara/Terrafame multi-metal mining company is Europe’s largest nickel open cast mine, it is also known for the largest wastewater leakage in the Finnish mining history and a series of other accidents. In this paleolimnological study, influences of a recently constructed treated waste water discharge pipeline into Lake Nuasjärvi were investigated by analyzing past (pre-disturbance) and present community compositions of key aquatic organism groups, including diatoms, Cladocera and Chironomidae, along spatial (distance, water depth) gradients. In addition to defining ecological changes and impacts of saline mine waters in the lake, chironomids were used to quantitatively reconstruct bottom water oxygen conditions before and after the pipe installation (in 2015). The diatom and cladoceran communities, which reflect more the open-water habitat, showed only relatively minor changes throughout the lake, but a general decrease in diversity was observed within both groups. Chironomids, which live on substrates, showed more significant changes, including complete faunal turnovers and deteriorated benthic quality, especially at the sites close to the pipe outlet, where also chironomid diversity was almost completely lost. Furthermore, the reconstructed hypolimnetic oxygen values indicated a major oxygen decline and even anoxia at the sites near the pipe outlet. The limnoecological influence of the pipe decreased at sites located counter-flow or behind underwater barriers suggesting that the waste waters currently have location-specific impacts. Our study clearly demonstrates that whereas the upper water layers appear to have generally maintained their previous state, the deep-water layers close to the pipe outlet have lost their ecological integrity. Furthermore, the current hypolimnetic anoxia close to the pipe indicates enhanced lake stratification caused by the salinated mine waters. This study clearly exhibits the need to investigate different water bodies at several trophic levels in a spatiotemporal context to be able to reliably assess limnoecological impacts of mining.