Reactive Configuration Research Articles

Gas-Phase Reactivity of Actinides Monocations with NH3: ICP-MS Experiments Combined with a DFT Study.

The reactivity of actinide monocations (Th+, U+, Np+, Pu+, Am+, and Cm+) with NH3 gas was studied in the reaction cell of an inductively coupled plasma-mass spectrometer (ICP-MS). Only Th+, U+, Np+, and Cm+ react completely with NH3 to form AnNH+, contrary to Pu+ and Am+. Differences in reactivity are found between U+/Pu+, Pu+/Cm+, and Am+/Cm+, which could resolve isobaric interferences in ICP-MS. DFT calculations were performed across the first half of the actinide series. The calculated reaction energy between An+ and NH3 reproduces the experimental trends in reactivity with Th+ > Pa+ > U+ > Np+ > Ac+ > Cm+ > Pu+ > Am+. The reaction path involves the initial formation of an AnNH3+ adduct followed by N-H bond insertion with the formation of HAnNH2+ and H2AnNH+ intermediate species and subsequent H2 loss. The trend in reactivity across the actinides is largely due to the first energy barrier and formation of the HAnNH2+ intermediate species. This limiting step is energetically unfavorable for the Pu+ and Am+ cations. For these cations, the excitation energy required to achieve a reactive configuration with two non-f electrons available for bonding is too high.

Reactive distillation configuration for the production of ethyl acrylate

Esters of acrylic acid have many industrial applications, but existing industrial processes are not economical. Ethyl acrylate, a precursor to polymers and other chemicals is one of them. The existing method of production of ethyl acrylate by esterification of acrylic acid with ethanol using a homogeneous catalyst and reactor-distillation combination has limitation in terms of product purity, corrosion and existence of possible side reactions. The present work proposes a novel reactive distillation (RD) column configuration for ethyl acrylate production, with 99.99 % acrylic acid conversion and 99.99 % ethyl acrylate purity with no effluent stream. The proposed configuration is analyzed using Aspen Plus steady-state simulation software. Sequential iterative sensitivity analysis is performed to obtain all structural and operating parameters leading to a minimum Total Annual Cost (TAC). The result shows that, there is 10.8 % improvement in the purity of aqueous stream using RD configuration compared to existing method and the overall TAC of the process at desired conditions is 87.77 × 103 $/year.

Reactive power capacity allocation technology of shore‐based power supply system of offshore oil production platform under different network topology reliability measures

AbstractTo improve the economy of offshore oil production platform shore‐based power transmission mode, the reactive power capacity allocation technology of offshore oil production platform shore‐based power supply system based on different network topology reliability measures was proposed. The optimization model of power supply system network topology and the structure model of voltage source converter high voltage direct current transmission system were established, the start and stop control scheme of flexible direct current (DC) transmission system was designed, and the operation parameters of converter station and DC line were monitored in real time. The topological structure of offshore oil production platform shore‐based power supply system is constructed, the mathematical model of flexible DC transmission system is established when the alternating current side voltage is balanced, the reactive power capacity configuration of offshore oil production platform shore‐based power supply system is optimized, and the life cycle cost results are calculated. The experimental results show that the algorithm proposed in this paper can obtain the optimal solution only after 26 calculations, with high optimization efficiency and good convergence effect. Reactive capacity configuration of shore‐based power supply system for offshore production platform can reduce failure rate and life cycle cost.

Reynolds-average Navier-Stokes turbulence models assessment: A case study of CH4/H2/N2-air reacting jet

Computational Fluid Dynamics has become a very powerful tool for developing engineering combustion devices, such as burners and furnaces. However, there are a wide variety of turbulence models, and some of them have proven to be more effective for some turbulent flow configurations than others. A reacting turbulent jet is a common flow configuration found in combustion engineering devices like burners. The present work assesses Reynolds-Average Navier-Stokes turbulence models, being tested on a CH4/H2/N2-Air reacting jet. Eight two-equation eddy-viscosity and three five-equation turbulence models were tested in the studied turbulent flow. Computational results were compared against experimental measurements in terms of flow field variables, mean mixture fraction, temperature, and species mass fraction. The findings suggest a strong influence of the turbulence model perforce on the mean mixture fraction as well as on the turbulence-chemistry interaction model. The modified version of the standard k-ε model proves to be the more reliable choice for this reactive flow configurations. Specially, where the flow patterns of the jet dictate the general flow physics. Near the fuel nozzle, both the Reynolds stress model with stress baseline k-ω (RSM-SBSL) and the standard k-ω model exhibit better agreement with experimental data than the conventional modified k-ε model. Moreover, findings from the standard modified k-ε model indicate a significant underestimation of spreading rates for radial samples in regions where jet spreading intensifies.

Energy saving design and control of side-streams reactive distillation configuration for diphenyl carbonate production process

Diphenyl carbonate (DPC), a phosgene-free precursor for polycarbonate production, has traditionally undergone industrial production through a well-established two-step transesterification process by a reactive distillation (RD) and a distillation column. Thermal enhancement techniques in RD, such as thermally coupled (TCRD) and hybrid heat-integrated (HIRD) methods, have consistently demonstrated significant improvements in energy efficiency, eliminating remixing effect and reducing total annual cost (TAC) during DPC synthesis. However, the combination of TCRD or HIRD with a side-stream configuration (SS) remains relatively underexplored, particularly in the context of DPC production. This study aims to address this gap by proposing a novel combination of TCRD/HIRD, incorporating both a one side-stream (SS1-TCRD and SS1-HIRD) and a two side-streams configuration (SS2-TCRD and SS2-HIRD). Employing a sequential iterative procedure for optimization, the study sought to minimize TAC. Results unveiled SS2-HIRD as the optimal configuration, showcasing a remarkable 47.27% reduction in energy consumption and a 31.46% decrease in TAC. Moreover, four proposed control structures (CS1∼CS4) were implemented for SS2-HIRD to ensure both product quality and process safety. Among all structures, CS4 exhibited remarkable efficacy in managing disturbances in feed and composition throughput, demonstrating the smallest integral of the absolute error (IAE) value.

Oxidation of Aqueous Phosphorous Acid Electrolyte in Contact with Pt Studied by X-ray Photoemission Spectroscopy.

The oxidation of the aqueous H3PO3 in contact with Pt was investigated for a fundamental understanding of the Pt/aqueous H3PO3 interaction with the goal of providing a comprehensive basis for the further optimization of high-temperature polymer electrolyte membrane fuel cells (HT-PEMFCs). Ion-exchange chromatography (IEC) experiments suggested that in ambient conditions, Pt catalyzes H3PO3 oxidation to H3PO4 with H2O. X-ray photoelectron spectroscopy (XPS) on different substrates, including Au and Pt, previously treated in H3PO3 solutions was conducted to determine the catalytic abilities of selected metals toward H3PO3 oxidation. In situ ambient pressure hard X-ray photoelectron spectroscopy (AP-HAXPES) combined with the "dip-and-pull" method was performed to investigate the state of H3PO3 at the Pt|H3PO3 interface and in the bulk solution. It was shown that whereas H3PO3 remains stable in the bulk solution, the catalyzed oxidation of H3PO3 by H2O to H3PO4 accompanied by H2 generation occurs in contact with the Pt surface. This catalytic process likely involves H3PO3 adsorption at the Pt surface in a highly reactive pyramidal tautomeric configuration.

Funnel and Gate Permeable Reactive Barrier Configuration for Contaminated Groundwater Remediation – Designing, Installation, and Modeling: A Review

Funnel and Gate Permeable Reactive Barrier Configuration for Contaminated Groundwater Remediation – Designing, Installation, and Modeling: A Review

A Differentiated Dynamic Reactive Power Compensation Scheme for the Suppression of Transient Voltage Dips in Distribution Systems

At present, with the construction of new power systems, the uncertainty of the system is increasing and the transient voltage stability of the power grid is becoming more and more complicated. For this reason, this paper proposes a differentiated dynamic reactive power compensation configuration method for suppressing transient voltage dip instability. The method first establishes a dynamic reactive power device configuration indicator system based on multiple-two-element notation, and then establishes a differentiated dynamic reactive power compensation device configuration model based on the node instability risk characteristics. The model takes the investment cost and suppression effect as the optimization objectives, and flexibly adjusts the optimization weights of its cost and suppression effect according to the high or low risk of the transient voltage instability of the compensation node, so as to realize the differentiated dynamic reactive power compensation. Compared with traditional compensation methods, differentiated compensation can significantly improve the economic benefits of reactive power compensation configuration. Finally, taking the IEEE39 node test system as an example, the improved TLBO algorithm is used to solve the model. The cost of differentiated compensation is reduced by 22.13%, with a similar suppression effect, which verifies the validity of the method proposed in this paper.

Direct production of diethyl carbonate from ethylene carbonate and ethanol by energy-efficient intensification of reaction and separation

This study presents a novel process for producing diethyl carbonate and ethylene glycol directly from ethylene carbonate and ethanol through reactive distillation. Previous studies have mainly focused on investigating two reactive distillation systems with a pressure swing azeotropic separation for producing diethyl carbonate. By integrating the two separated reactive distillation systems into a single flowsheet, an energy-efficient process is enabled. Especially, the need for separating the azeotrope mixture is eliminated, and the primary feed of methanol is not required due to the reaction stoichiometry. Two design alternatives have been proposed based on the reactive distillation configuration and catalyst employed. The first design significantly reduces the amount of equipment needed by utilizing two reactive distillation columns, while the second design offers high energy savings, as all reactions occur in a single reactive distillation column. Compared to the conventional process of producing individual dimethyl and diethyl carbonate, both design alternatives result in total energy consumption reductions of 12% and 24%, respectively, as well as total annual cost reductions of 12% and 14%, respectively. Furthermore, both design alternatives demonstrate a reduction in CO2 emissions by 15% and 11% respectively. Not only do these results demonstrate their economic viability, but they also indicate their effectiveness in CO2 mitigation. From an industry perspective, the two proposed design alternatives can be effectively implemented for the direct production of diethyl carbonate and mono-ethylene glycol by intensifying the existing dimethyl carbonate production process.

Dynamic Reactive Power Optimization Configuration of New Energy Power Station Based on Fault Limit Removal Time

The large-scale construction of long-distance, high voltage level transmission projects and sustained load demand increase negatively influence transient voltage stability. A certain amount of dynamic Var compensation at the receiving end of the power grid can significantly improve the stability. Most new energy power plants, such as wind power, and photovoltaic generation, have installed dynamic Var compensation devices. The potential for safety and stability control should be fully exploited. In this paper, it is concluded that the critical fault clearing time is the main index to measure the transient voltage stability of the system, and the critical fault clearing time has been extended by allocating dynamic Var compensation. According to these conclusions, a method for optimal allocation of dynamic Var compensation to improve critical fault clearing time is proposed. The method has determined the optimal capacity and the installation point. The effectiveness of the proposed method is illustrated through simulations on the actual power grid.

Structured Data Management for Investigating an Optimum Reactive Distillation Design

Reaction and separation are the two most important processes in the chemical industry that significantly affect the overall energy and cost requirements. Therefore, the operation of integrated reactive separation in a single equipment, such as reactive distillation, potentially increases the chemical process efficiency remarkably. To achieve that advantage, it is vital to design an optimum reactive distillation configuration in the preliminary evaluation. This paper proposes structured data management that can be used to encounter an optimum reactive distillation design. The approach simplified and reduced the data necessity from thousands to dozens by applying a systematic data sorting for the simulation results obtained from the Aspen Plus simulator. Using a case study that is highly relevant to the real chemical processes, i.e., the metathesis of 2-pentene, this study showed that the rule of thumb for determining the optimum design of conventional distillation can be adapted for reactive distillation technology.

Acoustic performance of a heat exchange silencer for marine diesel engine

For the noise contribution of a marine diesel engine, exhaust noise plays an important role, especially considering its low frequency characteristics. The marine exhaust silencer is an effective device to attenuate the engine exhaust noise. Expansion chamber or resonators have been the backbone of almost all marine exhaust silencers, but issue of bulkiness remains. It is well known that the passband for an expansion chamber is related to its geometric length. For a fixed firing frequency, if the exhaust gas is cooled, then the wavelength of the firing frequency can be reduced. Inspired by this principle, the heat exchanger and silencer are combined to improve the low frequency effect of the device. Various reactive configurations are tried to get a well-balanced silencing effect. The effectiveness-number of transfer unit method and acoustic finite element method are adopted to calculate the noise reduction effect with or without exhaust gas cooling. It is concluded that that the heat exchange silencer has satisfactory cooling effect on the exhaust gas, but its contribution to noise attenuation is very limited. Since the reduction of the exhaust gas temperature, low-frequency performance of the silencer is enhanced.

Structures and dissociation of iron porphyrin complexes by ion mobility and collision-induced dissociation mass spectrometry

A combination of ion mobility mass spectrometry (IMS-MS), collision-induced dissociation (CID), Rice–Ramsperger–Kassel–Marcus modeling, and computational chemistry was used to determine the structure and unimolecular chemistry of dimeric and trimeric sulfonated meso-tetraphenylporphyrins with negative charges from −2 to −5. By comparing experimental collision cross sections obtained from calibrated IMS drift times with calculated cross sections for the lowest energy calculated structures, it was confirmed that dimer species have a bridged structure where the two monomers are connected through iron–sulfonic interactions. Dimer species with the charge states −4 and −5 dissociate into two monomer units where the charge is distributed between the monomers. Dimers with lower charge states also lose neutral SO2 and SO3 groups. For trimeric species with charge states of −3 and −4, IMS identifies three and two isomers, respectively. It was confirmed that the −4 charged trimer isomers consist of one with three stacked monomers and one in which the third monomer unit is connected to a stacked dimer via two iron–sulfonic bonds (bridged/stacked). Both yielded the same CID breakdown diagram confirming that the two isomers likely interconvert prior to dissociation. The significantly larger density of states of the bridged–stacked structure compared with the stacked structure means the former is likely the reactive configuration.

Reactive Power Compensation Configuration of Offshore Wind Power Based on Economic Differential Pressure Theory

The conventional reactive power balance analysis method for offshore wind power transmission projects can be used to obtain many feasible solutions for reactive power compensation configuration, which requires a large number of simulation calculations to eliminate unreasonable schemes. The work is tedious and lacks theoretical guidance. In this paper, the main influencing factors, such as the current carrying capacity of offshore wind power and submarine cable, the mode of real-time power generation, and the reactive power output regulation of the wind turbine itself, are considered. The reactive power balance of offshore wind power transmission projects is derived. Combined with the economic differential pressure theory, the sea-side and land-side configuration methods of high reactance and dynamic reactive power compensation are put forward. On the basis of realizing real-time reactive power balance, the recommended reactive power compensation configuration scheme effectively reduces the active power loss of the transmission project, and at the same time, lowers the bus voltage of each node at sea, thus reducing the high risk of the excessive voltage of offshore wind farm. This project is supported by the Science and Technology Project of State Grid Corporation of China under “Research on multiple temporal and spatial coordinated optimal control theory for medium and long-distance large-scale offshore wind power transmission system” (No. 5100-202155305A-0-0-00).

Research on Optimal Allocation of Reactive Power Compensation in Offshore Wind Power Transmission System via AC Cable Based on Controllable Reactor

The capacitance of submarine cables with the same length and the same voltage level is more than 20 times that of overhead lines, which makes the reactive power for AC transmission system of offshore wind power greatly increase and the power flow is complicated, and it is easier to produce a series of problems such as reactive power return, low power factor, increased network loss, and terminal voltage rise, which puts forward higher requirements for reactive power compensation configuration scheme. Combined with practical engineering cases, this paper introduces the reactive power and voltage characteristics of the sea breeze system, as well as the problems and shortcomings of conventional reactive power compensation schemes. Finally, the reactive power allocation optimization scheme based on the new magnetically controlled controllable reactor MCR is proposed, which has the technical and economic advantages of low running loss, saving investment and land occupation, etc. It can be used as a beneficial supplement to the reactive power allocation scheme for the transmission system of offshore wind power with AC cable and has the value of engineering popularization.

A systematic matrix-based method for synthesis and optimization of Reaction/Distillation processes including Reactive Distillation

In order to reach product purity specifications, reactor outlet streams are often purified using distillation columns, and the unreacted feed is recycled to the reactor. This makes Reaction-Separation processes very important in chemical industries. In the current study, a new version of the Reaction/Distillation Matrix algorithm previously presented by the authors is presented. The current version of the algorithm is capable of generating Reactive Distillation configurations as attractive process alternatives and also recycle streams to prevent the loss of unreacted feed components. Besides, major modifications have been carried out to the algorithm to make it more efficient and user-friendly. Production of cumene and dimethyl ether were studied as case studies to evaluate the performance of the developed algorithm. The conventional sequences generated using the Reaction/Distillation Matrix algorithm were simulated by Aspen Plus and then optimized using the Genetic Algorithm. It is observed that cost of reactive distillation configuration was approximately 62 % and 10 % lower than for the conventional process in the cumene production and dimethyl ether production case studies, respectively.

Analysis of reactive power compensation of railway 20kV primary through line

With the increase of power load along the railway and stations and the popularization and use of 20kV distribution network, it has a great impact on the selection of voltage level of railway power supply. To solve this problem, the capacity rise effect of power through line, reactive power compensation capacity configuration of 10kV and 20kV Voltage levels are calculated and analyzed, and the MATLAB simulation model is established for simulation verification.

Diversity in Global Mining: Where We Are and What We Need to Do

We explore how diversity plays out in a historically male-dominated domain of international business – mining – by analyzing the diversity statements and initiatives reported by 25 of the top 50 global mining firms in terms of market value. We find that home country organizational field configurations play a pivotal role in determining how mining firms perceive diversity and the specific diversity dimensions they focus on. We distinguish between accommodative, defensive and reactive configurations to understand regional variation in the way mining firms manage diversity. We provide actionable recommendations to key stakeholders on adopting a proactive approach towards advancing diversity.

Novel Reactive Flex Configuration in Kiwi Wing Foil Surfboard

The creation of an ideal surfboard is art. The design and construction depend on the individual surfer’s skill level and type of the required performance. In this research, four fuselage concepts were carefully explored to meet the following unique needs: lightweight, strong, and a fast-manufacturing process. The fuselages were manufactured by compression moulding using skin and core materials. The skin material was selected to be unidirectional (UD) carbon fibre, discontinuous carbon fibre (SMC) and Filava quadriaxial fibre impregnated with epoxy, while the core material was selected to be lightweight PVC foam. To assess the mechanical performance, three-point bending has been performed according to BS-ISO 14125 and validated using Finite Element Analysis (FEA) using Ansys software. As expected, the flexural test revealed that the UD carbon fibre fuselage was the strongest and SMC was the weakest, while large deflection was seen in Filava fibre fuselages before failure, showing great reactive flex that promotes projection during surfing. The experimental results show good agreement with FEA simulation, and the locations of the physical failure in the fuselage matches the location of maximum flexural stress obtained from FEA simulation. Although all fuselages were found to carry a surfer weight of 150 kg, including a factor of safety 3, except the SMC fuselage, due to shrinkage. The Filava fibre fuselages were seen to have a large deflection before failure, showing great flexibility to handle high ocean waves. This promotes the potential use of reactive flex in high performance sports equipment, such as surfing boards. A large shrinkage must be taken under consideration during compression moulding that depends on fibre orientation, resin nature, and part geometry.

Stochastic Modeling of a Lifted Methane/Air Jet Flame with Detailed Chemistry

AbstractThis preliminary numerical study investigates a lifted methane/air jet flame in a vitiated coflow by means of the One‐Dimensional Turbulence (ODT) model. In the considered Cabra Burner configuration [Combust. Flame 143 491‐506 (2005)], a jet flame issues from a central nozzle into a vitiated coflow of hot combustion products from lean premixed hydrogen/air flames. ODT is a map‐based model for turbulent flow simulations which uses a stochastic formulation for the turbulent advection. The diffusion and reaction effects along the one‐dimensional domain are considered by temporally advancing deterministic evolution equations. ODT simulations are performed with a representation of the methane/air chemistry by a reduced 19‐species mechanism with 15 reactions and a detailed 53‐species mechanism with 325 reactions. In this work, we present centerline profile of temperature and species concentrations obtained from ODT simulations using a cylindrical ODT‐formulation. Additionally, two‐dimensional renderings of the temperature distribution are shown. Although the simulation of reactive jet configurations by means of ODT is not novel, the complex stabilization region depending on the flow conditions represents a challenge for the model. Considering the reduced order of the model, ODT is able to predict the flow characteristics and reasonably matches the existing experimental data.