Reactors In Series Research Articles

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.

Residence time distributions in a liquefier of material extrusion process

In this short communication, the residence time distribution of molten polymer in a liquefier of a material extrusion process is numerically investigated. The Laplace transform is used to easily fit the residence time distribution. As a result, the liquefier can be decomposed into a plug flow and a continuous stirred tank reactor in series. The local mean residence time is also studied numerically to provide information about the flow structure.

Correction: Analytical modeling of fault current limiter with coreless variable series reactor

Correction: Analytical modeling of fault current limiter with coreless variable series reactor

Analytical modeling of fault current limiter with coreless variable series reactor

Analytical modeling of fault current limiter with coreless variable series reactor

Multistep Synthesis of Paracetamol in Continuous Flow

p-Aminophenol (AP) is the key intermediate of the traditional synthesis of paracetamol. The method of obtaining AP included a selective reduction reaction of the generation of N-arylhydroxylamine (AHA) using nitrobenzene (NB) as the raw material, followed by a Bamberger rearrangement reaction to transfer AHA to the target product. The generation of AHA is a key step, but due to its structural instability and the incompatibility of the two reaction systems, one-pot synthesis of paracetamol faces great challenges. Considering that using flow reactors in series may avoid the problems faced by batch reactors, the article presents the strategy to obtain paracetamol via a continuous flow technology. In particular, we focus on condition screening in total synthesis experiments, including hydrogenation, Bamberger rearrangement, and amidation in flow. The continuous three-step synthesis process used NB as a raw material to generate AHA, which entered the downstream for timely conversion, achieving in situ on-demand preparation of the unstable intermediate AHA, avoiding cumbersome processing and storage processes. Moreover, each step of the reaction system exhibits excellent compatibility, and the work-up is simple.