Reactors In Series Research Articles

Loss Research and Thermal Analysis of BLDC Hollow-Cup Motor Under Reactor Suppression

In order to avoid overheating of a BLDC permanent magnet (PM) motor at high speeds, this paper focuses on the loss reduction of a 90 W 47,000 r/min BLDC hollow-cup motor. It is proposed to provide an optimizing method for the series reactors and the parameterization of reactors in the motor system. The finite element method (FEM) is used to calculate and analyze the time harmonic of air-gap magnetic flux density, stator core loss, and rotor eddy current loss in two cases: with a series reactor and without a reactor. By parameterizing the inductance value, the optimal resistance value is determined to minimize motor loss. In addition, an electromagnetic–thermal coupling analysis is conducted, and the results show that the temperature distribution of the stator core, winding, and rotor are improved under reactor suppression. Finally, an experimental platform is built to verify the temperature increase and the efficiency of the motor load operation. A clear reference for the research and optimization analysis of motor loss reduction is provided.

A comprehensive review of flexible alternating current transmission system (FACTS): Topologies,applications, optimal placement, and innovative models.

This paper is a comprehensive reference for researchers interested in flexible AC alternating current transmission systems (FACTS) technologies. This study investigates modified UPFC models. Besides UPFC, an overview of DPFC will be presented, and the critical differences between these advanced power flow control technologies will be discussed. In particular, we will do a comparative evaluation of three well-known DPFC models: Distributed Series Reactor (DSR), Distributed Static Series Compensator (DSSC), and Distributed Unified Power Flow Controller (DUPFC). This work also discusses the latest models of FACTS technology, such as Carbon Nanotubes (CNT), Multi-winding transformers (MWT), and Line-to-Line Compensators (LLC). Finally, this review paper introduces advanced optimization techniques for optimal placement and design of FACTS devices.

Comparison of Ammonia Removal from Ground Water in Attached Growth Process Using Over-burnt Brick with Suspended Growth Process without Any Media

Rising amount of ammonia in groundwater is rising problem in groundwater of Kathmandu. This has led to various diseases like blue baby syndrome to arise. So, it is necessary for efficient and safe removal of ammonia from drinking water. Since the physical-chemical system includes the major disadvantages of high operation and maintenance cost, the biological nitrification system can only be a good alternative to remove ammonia from ground water. Hence, an attempt is done in this research to treat ammonia contaminated water by biological nitrification process. Three reactors were constructed in series with media of over-burnt brick and other three in series were constructed without media. The study was carried out for five different flow rates of 10, 14.4, 18.8, 27.6 and 38.8 ml/min. Based on laboratory test the efficiency of these five different flow rates was plotted and conclusions were reached. Achievement of continuously increasing efficiency, which reached to 95–100% in the reactor provided with over-burnt media; reflects a success in the assumption that the over-burnt brick is good media to be used in bio filters for nitrification. The reactors with media have more efficiency than reactors without media. An average efficiency of 56.48% for reactors with media and 37.55% for reactors without media was observed for all the flows. The difference of 18.72± 0.2 was found between reactor with media and reactor without media in both series and single reactor. Low flow rates showed better ammonia removal than flow rates with higher flow rates such that a hydraulic retention time of 7.29 hour per reactor can be taken as design criteria for nitrification using over-burnt brick as media.

Study of balancing methods for parallel cable transmission lines

Cables are of vital importance for the transmission and distribution of electricity within the power grid. However, as the demand for electricity continues to grow, the transmission capacity of a single high-voltage cable is no longer sufficient to meet the required standards. It is therefore imperative to increase the transmission capacity of cables. The deployment of parallel cable transmission represents the most effective strategy for enhancing transmission capacity. However, due to the complex electromagnetic coupling relationship between cables, there is a possibility of current imbalance between cable lines in the same phase, which will have an adverse effect on the normal operation of power equipment and pose a significant threat to the security of the power system. In light of the aforementioned considerations, this paper primarily investigates the mitigation of parallel cable line imbalance. Initially, it examines the parallel cable line current imbalance factors through a theoretical lens, encompassing cable impedance and electromagnetic coupling arrangement. Subsequently, it assesses the efficacy of two proposed methods for reducing the imbalance degree of the parallel cable, namely, the adjustable reactor in series and the addition of a magnetic ring device. Furthermore, finite element simulation software is employed to simulate the two methods and verify their efficacy. Ultimately, a parallel cable plus magnetic ring test is conducted to verify the effectiveness of the magnetic ring.

Lightning surge analysis for cascaded H-bridge converter-based battery energy storage system

The lightning overvoltage in the cascaded H-bridge converter-based battery energy storage system (CHBC-BESS) is investigated in this paper. The high frequency (HF) model of CHBC-BESS is firstly developed. Four lightning strike cases are analyzed, including lightning striking the wind turbine (WT) blade, the transmission tower in the wind farm (WF), and the terminal tower of 35 or 220 kV grid. The influences of BESS layout schemes, lightning protection devices and line surge arresters (LSAs) are discussed. The results indicate that the surge originating from the 35 kV grid induces the highest overvoltage, with peak voltages of 496.54 kV at the grid side of the series reactor and 57.27 kV at the AC terminal of the CHBC-BESS. Though the reactor provides surge protection for CHBC-BESS, extreme conditions may still lead to a failure in the power conversion system (PCS). Additionally, overvoltage risks increase when the power modules (PMs) and battery clusters are dispersed; specifically, the peak voltage across AC terminals of submodule 1 (SM1) rises from 1.70 to 3.43 kV.

Methyl ester production process from palm fatty acid distillate using hydrodynamic cavitation reactors in series with solid acid catalyst

This study aims to optimize the reduction of free fatty acids (FFAs) in palm fatty acid distillate (PFAD) using hydrodynamic cavitation reactors (HCRs) in series and a solid acid catalyst for biodiesel production. Hydrodynamic cavitation is used to accelerate the esterification of FFAs using a heterogeneous acid catalyst. There are three HCRs units, and each HCR composed of a 3D-printed rotor and stator, is separated by flanges and equipped with a basket for holding Amberlyst-15 catalyst. Through response surface methodology (RSM), the esterification process is optimized by adjusting its optimal parameters, namely, methanol (2–12 wt%), circulation time (30–170 min), and rotor speed (1000–3000 rpm). The optimal conditions for achieving a maximum methyl ester purity of 89.76 wt% in converting FFA in first-step esterified oil are 9 wt% methanol (molar ratio of methanol to oil of 4:1), 133 min of circulation time, and 2000 rpm of rotor speed. An 82.48 wt% biodiesel yield is achieved from the HCRs in series under the optimal conditions. Scanning electron microscope images reveal that after the esterification process, there are minor cracks and defects on the catalyst’s resin surface, indicating the presence of residual reactants. Further examination of the catalyst after the esterification process, reveals an average absorption pore diameter of 341.41 Å and BET surface area of approximately 41.68 m2/g. Although there were slight physical changes in the catalyst, HCRs technology offers a viable FFA reduction process that could enhance biodiesel production efficiency. Moreover, the optimized conditions achieved in this study contribute to the advancement of biodiesel production processes and provide insights into the performance of the catalyst used.

Unveiling the synergism and reaction pathway of ethyl acetate removal in DBD/absorption integrated reactor

The experiment employs dielectric barrier discharge (DBD) combined with absorption integrated reactor (DCAIR) for higher concentration ethyl acetate removal and studies the synergism of DCAIR technology and the reaction pathway of ethyl acetate. Among three technologies of DCAIR, DBD and DBD combined with absorption series reactor (DCASR), DCAIR achieved the highest removal efficiency (RE) of ethyl acetate at similar input power. Fixed gas flow rate of 1000 ml/min and cC4H8O2in of 5000 mg/m3, the average REs of DCASR and DCAIR are higher than that of DBD by 31.2 % and 34.2 %, respectively. For the efficiency compensation mechanism, one of synergies in DCAIR, RE of ethyl acetate could exceed 80 % at the input power of 15 W. Energy consumption evaluation shows when RE > 80 %, the max energy efficiency of three technologies is in the order 70.0 g/kWh (DCAIR) > 5.1 g/kWh (DCASR) > 3.0 g/kWh (DBD). Tail gas and absorbent analysis reveals DCAIR can enhance mineralizing ethyl acetate and eliminating the secondary pollutants (e.g., O3, gaseous organic intermediates, and COD, etc.) effectively, due to its special structure of reactor. According to FT-IR spectra, the degradation mechanism and reaction pathway of ethyl acetate in DCAIR has been unveiled.

A rigorous model for hydrogen response in industrial propylene polymerization loop reactors: From micro-mechanism to macro-behavior

In spite of playing a chain transfer agent role, the hydrogen activation effect in propylene polymerization with Ti-based Ziegler-Natta catalysts, so called “hydrogen response”, is usually explained by the dormant-site theory in polymer chemistry. However, how the micro-mechanism at the catalyst site scale affects the macro-behavior of industrial processes is unrevealed. This work aims at developing a rigorous model that can accurately describe hydrogen response and predict polymer chain microstructure for an industrial propylene polymerization process consisting of loop reactors in series. The model is comprised of a kinetic model, a thermodynamic model, and a macroscopic non-ideal loop reactor model. To describe hydrogen response, an elaborated kinetic model is established based on a consistent dormant site reactivation mechanism assuming a multi-site model. The model predictions are in good agreement with plant data, after taking the dormant sites reactivated by hydrogen into account. The proposed model is capable of fully assessing the effects of various process conditions, during steady-state and grade transition processes, on the macro-behavior (i.e., production, slurry density) as well as polymer properties (i.e., melt flow index, molecular weight distribution) in the industrial loop reactors. The underlying correlations are also discussed.

Exploring innovative strategies for precipitation extent enhancement in a downscaled Bayer process tank

AbstractThe Bayer process is a cornerstone of alumina production, and its precipitation stage holds the key to both efficiency and product quality. In this study, we embarked on a comprehensive exploration of strategies to enhance the precipitation extent of aluminium hydroxide, a pivotal step in the Bayer process. Utilizing a newly constructed reactor, along with experiments using reactors in series, we rigorously experimented with various factors, including the addition of hydrogen peroxide (H2O2) as an enhancer, seed activation methods, the integration of a hydrocyclone within the processing unit, the application of a magnetic field, and the injection of supersaturated liquor midway through the process. These diverse strategies were systematically assessed to decipher their individual and synergistic effects on precipitation extent. Our research aims to uncover the optimal conditions for maximizing alumina precipitation while maintaining product quality and seed particle stability. By offering new insights and practical solutions, this study contributes to the ongoing advancement of alumina production within the Bayer process.

Simulation Analysis and Experimental Research on Vibration Characteristics of Series Reactors in Multiple Operating Status

Abstract This article examines the vibration properties of reactors across various operational scenarios, including normal operation, interturn arc short circuit faults, and interturn metal fusion short circuit faults. It begins by analyzing the vibration mechanism of reactors, drawing upon principles of electromagnetic induction and Ampere’s law. Then, a multi condition mechanical-electromagnetic interaction model was established for the series reactor, and the axial electrodynamic force distribution of the reactor was analyzed. Finally, a vibration characteristics test platform for series reactors under multiple operating conditions was built, and the vibration velocity distribution of the reactors was analyzed. The research results indicate that under normal operating condition, the maximum vibration velocity of the reactor appears at its lower end; When the Interturn arc short circuit fault occurs, the vibration speed at different positions of the reactor increases, and the vibration velocity at the short-circuit point will significantly increase with the development of the short-circuit fault; When the interturn metal fusion short circuit fault occurs, the amplitude of the vibration signal at the short-circuit point is greater than that of the arc short-circuit vibration signal.

Desalination of Seawater, Synthetic Saline Irrigation Water and Produced Water Using Nano Zero Valent Metals: Results from a Pilot-Scale Desalination System

Two pilot-scale desalination systems employing carbon modified nano-sized, zero valent metals (n-ZVMs) were manufactured and tested to determine (1) the degree to which high-salt water (20 to 130 mS) could be desalinated and (2) if this degree of desalination could be maintained throughout an extended treatment period. The two pilot systems (referred to as Generation 1 and Generation 2) consisted of parallel lines of four individual reactors in series, a settling tank and an activated carbon cell at the end of each reactor line. The system capacity was 300 gal in Generation 1 and 600 gal in Generation 2 with a total hydraulic residence time of 6 h per reactor line (one hour per cell/tank). A slurry of n-ZVMs manufactured from mixtures of ferrous sulfate and green or black tea extract was introduced in the first reactor on each line to yield approximately 5 to 45 g of nano metal per 100 L of influent salt water based on dosing experiments required to achieve maximum salt removal at each of the three influent salt contents used, 28 mS, 44 mS and 123 mS. Once dosing was set, continuous runs (14 days, 23 days and 9 days) were carried out. The results demonstrated that maximum removal occurred with 10 g/100 L of salt for the 30 mS salt solution, 16 g/100 L of salt for the 40 mS influent water and 40 g/100 L for the 130 mS influent. Salt removal (expressed as Na+ and Cl− removed) approached 78% for the 30 mS influent and 41 mS influent, respectively, while removal for the highest concentration salt influent (130 mS) approached 81%. Continuous operation over the extended time-period showed no significant decrease in salt removal with a typical day to day variation of no more than 10%, suggesting that this approach to desalination could rapidly provide usable water from saline aquifers, seawater or even produced water.

Calculation Method for Voltage Distribution of Dry Hollow Series Reactor Under Lightning Impulse

Calculation Method for Voltage Distribution of Dry Hollow Series Reactor Under Lightning Impulse

Design and Analysis of Transmission Lines Connecting Power System Generators to the Grid

According to the actual requirements, it is necessary to design a line connecting the 150MW hydropower station and the 230KV hydropower station. The first is to plan the overall process of the project, by consulting the data, objectively evaluating the transmission line parameters, combining Matlab and Excel to calculate the transmission line parameters, including barrier current calculation and safety analysis, and finally combining power system simulation and cost calculation, the only one is selected from hundreds of scenarios. Rationale, power flow analysis, and power loss analysis are used to evaluate transmission lines, including series reactors and new transmission lines in parallel. The process reflects the continuous refinement of the initial design to create a transmission line that is both economical and safe.

Grazing resistance developed in Escherichia coli K-12 during coexistence with a bacterivorous protist.

A development of grazing resistance in Escherichia coli K-12 was examined in the presence of a bacterivorous protist, Spumella sp. TGKK2. Two transformants were generated from E. coli K12 for grazing experiments. One was E. coli K-12-TGF, which possesses tetracycline resistance and green fluorescence. The other was E. coli K-12-KRF with kanamycin resistance and red fluorescence. These strains can be selectively colonized on antibiotic-containing agar media and further confirmed by their fluorescent colors. First, we added protist-untouched E. coli K-12-KRF to protist-touched residual E. coli K-12-TGF that had been attacked by Spumella sp. TGKK2 in a batch test. Then the survivability of the respective strains was investigated. Consequently, E. coli K-12-KRF was predated preferentially. On the other hand, E. coli K-12-TGF in the same tube was less predated, indicating some grazing resistance. Similar phenomena were observed when the conditions of these two strains of bacteria were reversed. Also, a continuous culture device supplied with a glucose-containing medium as a substrate was operated. The device connected two complete mixed reactors in series. E. coli K-12-TGF was cultivated in the first reactor, and then grown E. coli K-12-TGF was predated by Spumella sp. TGKK2 in the second reactor. The effluent in the second reactor containing residual E. coli K-12-TGF and Spumella sp. TGKK2 was supplemented with batch-cultured E. coli K-12-KRF. Consequently, it was confirmed that bach-cultured E. coli K-12-KRF never exposed to protist was predated preferentially. These findings reveal that E. coli K12 acquires some predation resistance through coexistence with the bacterivorous protist.

Assessing operational issues in a modular sewage treatment plant and providing remedies via comprehensive modeling and simulation through GPS-X

In this study, an existing but faulty modular sewage treatment plant (STP) with a capacity of 100 m3/day has been modeled and assessed using GPS-X software, combined with sensitivity analysis to confirm an underlying but critical operational issue of an STP. Currently, the STP shows <5 % ammonia removal at an average influent ammonia concentration of 50 mg/L, along with the problem of partial BOD removal. The treatment units comprise an equalization tank, two moving bed biofilm reactors (MBBRs) in series, a tube settler and a sand filtration unit. Sensitivity analysis helped decipher the most influential kinetics/stoichiometric parameters, which assisted in achieving a precise model calibration. Post calibration, the modified model was re-simulated for each constituent treatment unit based on the mass balance of four major output parameters viz. NH4-N, biochemical oxygen demand, dissolved oxygen and alkalinity. Real experimental/measured values spanning over 8 months were analyzed during the calibration phases (including both static and dynamic calibration phases). The calibrated GPS-X model was simulated using various input factors to find a possible remedial solution and understand the critical limitation of the existing plant. As a remedial measure, a pre-anoxic tank with an operational volume of 15 m3 and a recirculation ratio of 3 was proposed for the existing STP. A proper experimental design and statistical tools further helped achieve the most optimum and techno-economically feasible solution for an MBBR-based biological treatment unit. This helped effectively manage wastewater pollution in a modular treatment system.

Glycerolysis-Interesterification of Palm Olein and Coconut Oil Blend using Two High-Shear Continuous Stirred Tank Reactors

Abstract This study aimed to synthesize structured lipids containing high mono- and diacylglycerol by glycerolysisinteresterification of palm olein and coconut oil blend in two high-shear continuous stirred tank reactors in series. The result showed that various flow rates of 11 mL/min to 23 mL/min did not significantly increase mono- and diacylglycerol concentration, while at a flow rate of 26 mL/min only a low concentration of mono- and diacylglycerol was formed. However, a flow rate 20 mL/min and an agitating speed of 2000 rpm produced mono- and diacylglycerol concentration of 61.7% with the highest productivity of 2.1%/min and a triacylglycerol conversion of 64.6%. The slip melting point, melting point, hardness, emulsion capacity, and stability were 23.77 oC, 30 oC, 14.6 N, 65.15%, and 59.15%, respectively. The product’s solid fat content at 25 oC was lower than cocoa butter. The product contained β’ and β crystals, thus it can be applied as a cocoa butter substitute.

Tailoring activity on effect of loadings over praseodymium oxide catalyst in methanation

Most methanation reactions used basic catalysts to achieve high CO2 conversions. Therefore, in this study, praseodymium oxide was selected and synthesized using ratio Ru/Mn/Pr (5:30:65) and Al2O3 as support. From the result, it successfully converted 96 % of CO2 gas at calcination temperature of 800 °C using one series reactor. When the praseodymium-based loading is varied, the trend CO2 conversion is higher at 65 %wt and slightly decreased when increased to 85 wt%. Then, two series furnace reactors were applied and the Ru/Mn/Pr (5:30:65)/Al2O3 catalyst exhibited a slightly increased CO2 conversion with 98 %. According to X-ray diffraction analysis, the catalyst is amorphous with the presence of active species MnO2 and Pr2O3. In contrast, FESEM analysis showed that the catalyst surface was covered with large crystalline solids of irregular size which align with amorphous structure. Electron dispersive X-ray analysis shows the presence of all active element. Meanwhile, surface area of catalyst is ​​59.22 m2/g from Nitrogen analysis.

Heat dissipation design of the mine-used inverter output filtering device

During long-distance transmission, pulse width modulation (PWM) signals are subject to voltage reflection. This results in spike voltages and high du/dt values at the motor end. Suppression is carried out by utilizing a series reactor at the output of the inverter. And the filtering parameters are optimally designed. Then, the EMF characteristics of the output reactor are analyzed and power losses are calculated. On this basis, an integrated heat dissipation scheme is proposed to design the output reactor for forced cooling. It is verified by ANSYS/Icepak simulation, which shows that the filter has good heat dissipation performance.

The microbiome of two strategies for ammonia removal with the sequencing batch moving bed biofilm reactor treating cheese production wastewater.

Cheese production facilities must abide by sewage discharge bylaws that prevent overloading municipal water resource recovery facilities, eutrophication, and toxicity to aquatic life. Compact treatment systems can permit on-site treatment of cheese production wastewater; however, competition between heterotrophs and nitrifiers impedes the implementation of the sequencing batch moving bed biofilm reactor (SB-MBBR) for nitrification from high-carbon wastewaters. This study demonstrates that a single SB-MBBR is not feasible for nitrification when operated with anerobic and aerobic cycling for carbon and phosphorous removal from cheese production wastewater, as nitrification does not occur in a single reactor. Thus, two reactors in series are recommended to achieve nitrification from cheese production wastewater in SB-MBBRs. These findings can be applied to pilot and full-scale SB-MBBR operations. By demonstrating the potential to implement partial nitrification in the SB-MBBR system, this study presents the possibility of implementing partial nitrification in the SB-MBBR, resulting in the potential for more sustainable treatment of nitrogen from cheese production wastewater.

Research on the influence of nonuniform inflow on steady-state hydraulic performance of reactor coolant pump

Reactor coolant pump (RCP) is one of the most important equipment in the reactor, its safety and reliability is quite important to the nuclear safety. In Advanced Passive (AP) series reactors, the RCPs are directly connected with the lower chamber of steam generator (SG), while other reactors would add a long straight pipe section in front of the RCP inlet. This design is beneficial for simplifying system and reducing pipe resistance, but would also make the inflow condition of pump inlet more complex, which would bring some influences on the hydraulic performance of RCP. In this work, a high-accuracy experimental and measuring system is established to investigate the influence of nonuniform inflow on steady-state hydraulic performance of RCP. A numerical study is also presented to validate the experimental results and influence mechanism. As a result, it was found that nonuniform inflow have a significant impact on head, power and efficiency of the RCP, the influence mechanism is also discussed in this paper.