Records with Subject: Process Design
Showing records 1 to 25 of 2098. [First] Page: 1 2 3 4 5 Last
Machine Learning Aided Prediction of Glass-Forming Ability of Metallic Glass
Chengcheng Liu, Xuandong Wang, Weidong Cai, Yazhou He, Hang Su
February 19, 2024 (v1)
Keywords: glass-forming ability, Machine Learning, metallic glass, optimal design
The prediction of the glass-forming ability (GFA) of metallic glasses (MGs) can accelerate the efficiency of their development. In this paper, a dataset was constructed using experimental data collected from the literature and books, and a machine learning-based predictive model was established to predict the GFA. Firstly, a classification model based on the size of the critical diameter (Dmax) was established to determine whether an alloy system could form a glass state, with an accuracy rating of 0.98. Then, regression models were established to predict the crystallization temperature (Tx), glass transition temperature (Tg), and liquidus temperature (Tl) of MGs. The R2 of the prediction model obtained in the test set was greater than 0.89, which showed that the model had good prediction accuracy. The key features used by the regression models were analyzed using variance, correlation, embedding, recursive, and exhaustive methods to select the most important features. Furthermore, to... [more]
Performance Improvement Overview of the Supercritical Carbon Dioxide Brayton Cycle
Xurong Wang, Longwei Zhang, Zhenhua Zhu, Mingjiang Hu, Jing Wang, Xiaowei Fan
February 19, 2024 (v1)
Keywords: binary mixture, combined cycle, performance improvement, review, supercritical carbon dioxide cycle
Efficiency and compactness are core strengths of the supercritical carbon dioxide (sCO2) Brayton cycle, which is considered an alternative to the steam Rankine cycle for moderate-temperature heat sources (350−800 °C). Numerical investigations on system design and analysis have received considerable attention, with the aim of improving the sCO2 cycle from the viewpoint of thermodynamics. This paper reviews and compares previous studies in the literature to survey different cycle layouts, operating parameters, and working fluids of the sCO2 cycle. Performance enhancement approaches are categorized into three classes according to characteristics: conventional methods, CO2 mixtures, and combined cycles. The strengths, weaknesses, and limitations of each categorized method are discussed. This research is expected to provide a roadmap for performance improvement that meets the interests of researchers.
Study on Process Parameters in Hydrothermal Liquefaction of Rice Straw and Cow Dung: Product Distribution and Application of Biochar in Wastewater Treatment
Asiful H. Seikh, Hamad F. Alharbi, Ibrahim A. Alnaser, Mohammad R. Karim, Jabair A. Mohammed, Muhammad Omer Aijaz, Ahmed Hassan, Hany S. Abdo
February 10, 2024 (v1)
Keywords: bio-char, bio-oil, colorants, cow dung, hydrothermal liquefaction, rice straw
In this study, rice straw (RS) and cow dung (CD) waste were hydrothermally processed for the recovery of bio-oil and biochar. The hydrothermal experiments were performed in a 5 L capacity reactor under the following process conditions: temperature (240−340 °C), solvent to biomass ratios of 1:1, 1:2, 2:1, 1:3 and 3:1, a time of 1 h and a pressure of 15 bar. The HTL products were characterized via FTIR, SEM and GC−MS (gas chromatography mass spectrometry). It was seen that the maximum bio-oil yield was 32.5 wt% and the biochar yield was 18.5 wt% for the 2:1 RS:CD mixture at a temperature of 320 °C. The bio-oil contained hexadecane, heptadecane, octadecane and other hydrocarbons, and their presence was confirmed by GC−MS. The biochar was analyzed, and it was used in wastewater treatment to remove the colorants. The biochar also showed some promising results in the colorants removal study, with an efficiency of more than 76%.
Effect of the Encapsulation Process on the Viability of Probiotics in a Simulated Gastrointestinal Tract Model Medium
Madina Jumazhanova, Zhaynagul Kakimova, Yerlan Zharykbasov, Samat Kassymov, Gulmira Zhumadilova, Alibek Muratbayev, Marzhan Tashybayeva, Anuarbek Suychinov
February 10, 2024 (v1)
Keywords: alginate, capsule, encapsulation, gelatine, probiotics, viability
The primary objective of this study was to investigate the survival rate of three species of encapsulated bacteria (Propionibacterium acidipropionicici, Propionibacterium freudenreichii, and Propionibacterium thoenii) in model solutions designed to simulate the acidity levels found within the human gastrointestinal tract. The capsules were prepared by extrusion from gelatin and sodium alginate in a 1:1 ratio on a laboratory encapsulator. The use of gelatin and sodium alginate was found to provide optimum characteristics suitable for encapsulation of live bacteria. Three strains of Propionibacterium asidirgorionici, Propionibacterium freudenreichii, and Propionibacterium thoenii were subjected to in vitro assay to evaluate their probiotic potential. The final cell survival rate of P. freudenreichii was 105 CFU/mL, indicating that this probiotic is sensitive to acidic medium. The viability of encapsulated probiotics was studied in a model medium simulating the gastrointestinal tract. It... [more]
Energy and Exergy Analysis of Hydrogen-Based Fluidized Bed Direct Reduction towards Efficient Fossil-Free Ironmaking
Zhan Du, Wanchao Liu, Feng Pan, Zheng Zou
February 10, 2024 (v1)
Keywords: energy and exergy analysis, fluidized bed, fossil-free ironmaking, H2 direct reduction, process design
Hydrogen-based fluidized bed direct reduction (H-FBDR) is an important and promising route for fossil-free ironmaking. In this study, to achieve the optimal operation state of energy use and exergy efficiency, the influences of the metallization process and the ratios of H2 injected on the energy and exergy flows in the H-FBDR process are studied. The results show that the thermodynamically designed two-stage reduction process (first: Fe2O3→FeO; second: FeO→Fe) requires a smaller H2 quantity than other metallization processes. According to the mass, energy, and exergy balance analyses, variations in the H2 consumption, exergy destruction, and energy/exergy losses of the overall system, iron ore preheater (F1), fluidized bed reactor system (R), heat exchanger (E), and gas preheater (F2) with different ratios of H2 injected (η) are derived. The total H2 consumption, total exergy destruction, and energy/exergy losses rise with increasing η, and sharp increases are observed from η = 1.3 to... [more]
Hydraulic Design of Sediment-Trapping Basin in Wadis Using Empirical Equations and Deposition Processes
Abubakr Taha Bakheit Taha, Ali Aldrees, Ahmed Moustafa Ahmed Moussa
February 10, 2024 (v1)
Keywords: annual total load, empirical equations, King Fahad Dam, sediment-trapping basin, Wadi Bishah
Reservoirs overflow during flood season because of sedimentation cycles, which severely affects their effectiveness. Siltation is a major problem in dams constructed in waterways in arid and semi-arid areas. Therefore, the reservoirs in wadis lose their capacity due to sedimentation. This study determines an optimal design of the trapping basin on steep slope areas for Wadi Bishah in the Asir region of southwestern Saudi Arabia. The empirical design criteria of the sediment-trapping basin is used to mitigate the effects of sedimentation in the King Fahd Dam. The empirical design of the trapping basin constructed upstream of the dam located in the wadi is presented. Moreover, the annual suspended and bed sediment load (Qs and Qb) techniques for estimating the volume of sediments are used, and the relationship between the sediment trapping efficiency and size is determined. The sediment trapping in Wadi Bishah upstream sediment-trapping basins is selected to reduce the amount of sediment... [more]
Optimization Method for Hot Air Reflow Soldering Process Based on Robust Design
Linjie Ran, Dong Chen, Cai Chen, Yubing Gong
February 10, 2024 (v1)
Keywords: process design, reflow soldering, robust optimization, Surrogate Model
The process design of hot air reflow soldering is one of the key factors affecting the quality of PCBA (Printed Circuit Board Assembly) component products. In order to improve the product quality during the design process, this paper proposes a robust optimization-based finite element simulation analysis method including significant influencing factor screening, robustness evaluation, robust optimization, and reliability verification for the reflow soldering process. The simulation model of the reflow soldering process temperature field based on experiments is constructed and validated. Sensitivity analysis is used to select important influencing factors, such as the last five set temperature zones (T5 to T9) in the reflow oven and the thermal properties of materials such as PCBs (printed circuit boards), BGAs (ball grid arrays), and solder paste, as well as noise factors like the heating environment during the soldering process. Several surrogate models are used to construct the respo... [more]
Design and Analysis of a Novel Air Bubble Curtain for Mixing and Aeration in Process Vessels
Omar Chaalal, Chandra Mouli R. Madhuranthakam, Husain Al Hashimi, Marouane Chaalal, Weam S. K. Abudaqqa
January 12, 2024 (v1)
Keywords: bubble curtain, Mixing, pilot-scale studies, process vessels, residence time distribution
This article focuses on designing and analyzing a new method for mixing in process vessels. We propose using an air bubble curtain to accomplish the desired mixing. The air bubble curtain used in this study is made of an empty pipe with several holes through which air is pumped, which in turn produces a swarm of bubbles that causes pseudo-turbulent mixing in the tank filled with a liquid solution. A uniform distribution of bubbles within the tank was assured by maintaining a see-saw movement of the air bubble curtain. Mixing inside the tank was quantified by measuring the salt concentration in a laboratory model tank (30 cm × 30 cm × 30 cm) and a pilot-scale tank (200 cm × 100 cm × 100 cm). The optimal flow rates of air and the mixing time in both tanks that can achieve complete mixing were obtained from the experimental results. The proposed air bubble curtain can be of potential use in wastewater treatment, biotechnology, and aquaculture where turbulent mixing is required with minimu... [more]
Energy-Saving Testing System for a Coal Mine Emulsion Pump Using the Pressure Differential Flow Characteristics of Digital Relief Valves
Jie Tian, Wenchao Liu, Hongyao Wang, Xiaoming Yuan, Rulin Zhou, Junshi Li
January 12, 2024 (v1)
Keywords: digital relief valve, emulsion pump, energy saving testing, flow control, water-based hydraulic system
Most energy-saving testing methods for plunger pumps use hydraulic motors. The loading test of coal mine emulsion pumps generally uses an overflow valve as the loading unit, which is characterized by high energy consumption. The coal mine emulsion pump uses emulsion as the transmission medium, and the viscosity and lubricity of the emulsion are much lower than those of hydraulic oil, which creates great difficulties in the development of high water-based hydraulic products. The nominal flow rate of the emulsion motor is much smaller than that of the emulsion pump, and there is no mature and reliable water-based flow control valve. Based on the above reasons, traditional energy-saving testing methods cannot be utilized for the testing process of emulsion pumps. The loading test of emulsion pumps generally uses an overflow valve as the loading unit, and during the testing process, all electrical energy is converted into internal energy, resulting in very high energy consumption. This art... [more]
Unraveling Oxygen Transfer Behavior in Submerged Arc Welding Using CaF2-SiO2-CaO Fluxes
Jin Zhang, Jun Fan, Dan Zhang
January 12, 2024 (v1)
Keywords: flux, multi-zone model, oxygen content, oxygen transfer, submerged arc welding (SAW), thermodynamic equilibrium, weld metal composition, welding metallurgy
The purpose of this study is to investigate the transfer behavior of oxygen during the submerged arc welding process using CaF2-SiO2-CaO fluxes. In contrast to previous research that only focused on the final oxygen content in the final weld metal, this study introduces two new parameters, ΔdO and ΔwO, to quantify the oxygen transfer in essential regions: the droplet and weld pool zones, respectively. The transfer behavior of oxygen is analyzed by using typical Multi-Zone and equilibrium models. The results indicate that the Multi-Zone model is capable of capturing the metallurgical processes of oxidation and subsequent reduction during the submerged arc welding process. Moreover, the Multi-Zone model demonstrates superior predictive accuracy in estimating oxygen content in the metal compared to the equilibrium model. Based on measured values and metallurgical data, this article analyzes the oxygen transfer mechanism and non-equilibrium state in the submerged arc welding process from b... [more]
Axial Force Calculation Model for Completion String with Multiple Point Resistances in Horizontal Well
Zhen Nie, Shuzhe Shi, Bohong Wu, Xueqin Huang
January 12, 2024 (v1)
Keywords: axial force, completion string, hook load, horizontal well, local resistance
Frequent accidents may happen during the string run-down and pull process due to the lack of accuracy in the prediction of string force analysis. In order to precisely predict the completion string axial force in horizontal wells, a new model is established, and an in-house software has been developed. The model aims to predict the multiple local resistances that occur at different points on the completion string, which makes up for the technical defects of the commonly used software. It can calculate resistance at different points of the string, which will lead to varying hook load amplification. This method can also predict the axial force of the completion string. By changing the hook load, location, and direction, the resistance can be determined more accurately. Based on the calculation and analysis, the relationship between local resistance, the blocking point, and the amplification factor is also obtained. Furthermore, this model is used to analyze the local resistance of a hori... [more]
Research on the Formulation Design of Nano-Oil Displacement Agents Suitable for Xinjiang Jimusaer Shale Oil
Wei Wang, Xianglu Yang, Jian Wang, Mengjiao Peng, Liqiang Ma, Mengxiao Xu, Junwei Hou
January 12, 2024 (v1)
Keywords: chemical flooding, enhanced oil recovery, Jimusaer shale oil, nano-oil displacement agent
In order to improve the recovery efficiency of the Jimusaer tight reservoir in Xinjiang, the nanometer oil displacement agent system suitable for the Jimusaer reservoir was used. In view of the low permeability, high formation temperature, and high salinity characteristics of the prepared water in the Jimusaer tight conglomerate reservoir in Xinjiang, the performance of the nanometer oil displacement agent affecting oil recovery was studied; the study considered interfacial tension, temperature resistance, wetting performance, static oil washing efficiency, and long-term stability. Nanometer oil displacement agent No. 4 had the lowest interfacial tension and could reach the order of 10−1 mN∙m−1; it had excellent temperature resistance and the best static oil washing efficiency and stability. Nano-oil displacement agent No. 2 had the best emulsification performance and wettability and also had good stability. By studying the performance and final oil displacement effect of the nano-oil... [more]
Design of Radial Flow Channel Proton Exchange Membrane Fuel Cell Based on Topology Optimization
Cheng Qu, Yifan Zhang, Zhihu Zhang, Minggang Zheng
January 5, 2024 (v1)
Keywords: average depth model, PEMFC, radial flow channel, topological optimization, volume constraints
In this paper, the flow channel of the radial proton exchange membrane fuel cell (PEMFC) is optimized by the topological optimization method. Using the SNOPT algorithm, a two-dimensional stable constant temperature model is freely constructed in the cyclic sector design domain. Topology optimization aims to maximize the efficiency of PEMFC and minimize the energy dissipation of reaction gas. We analyze radial topology flow channels’ mass transfer capacity and cell performance with different maximum volume constraints. The results show that under high current density, the performance of the optimized channel is significantly better than that of the traditional channel. Increasing the maximum volume constraint is beneficial for improving the mass transfer of PEMFC. At 0.6 V, the cell performance of Scheme 4 is 14.9% higher than the serpentine flow channel and 9.5% higher than the parallel flow channel. In addition, in the optimal selection, 3D simulation modeling is carried out for more... [more]
Microwave-Assisted Reductive Amination under Heterogeneous Catalysis for the Synthesis of β-Adrenergic Agonist and Related Structures
Fabio Bucciol, Mariachiara Colia, Erica Canova, Giorgio Grillo, Emanuela Calcio Gaudino, Giancarlo Cravotto
November 30, 2023 (v1)
Keywords: microwave-assisted reactions, Process Intensification, ractopamine:HCl, raspberry ketone, reductive amination, transition-metal catalysts
Reductive amination is a powerful tool in sustainable organic synthesis that allows chemists to access a wide range of valuable amine products using renewable feedstocks and mild reaction conditions, with minimal waste generation. Practical applications can be found in various fields, including pharmaceuticals, contributing to greener and more sustainable chemical processes. In this work, we present a heterogeneous (Rh and Pt) catalyzed protocol for the fast and efficient synthesis of ractopamine hydrochloride (β-adrenergic drug) under microwave-assisted reductive amination protocol starting from raspberry ketone and octopamine. Microwave (MW) successfully accelerated the hydrogenation reaction and reduced the reaction time from 13 h to only 3 h under mild conditions (50 °C at 10 bar). The best catalysts were Pt/C and Rh/C, which led to high conversion and selectivity towards ractopamine:HCl. Different solvents and ketone substrates were also experimented. Acetophenone, cyclohexanone,... [more]
Design and Study of a Large-Scale Microwave Plasma Torch with Four Ports
Yedai Hu, Wencong Zhang, Jiahui Han, Huacheng Zhu, Yang Yang
November 30, 2023 (v1)
Keywords: 3D model, four-port microwave source, high microwave efficiency, large-scale MPT
The microwave plasma torch (MPT) has gained popularity in industrial applications due to its high energy density, ionization levels, and high temperature. However, the non-uniform and unstable plasma generated by microwave plasma sources has limited the production of large-scale MPTs. This paper proposes a novel MPT device utilizing a four-port microwave source (2.45 GHz, 4 kW) to address these issues. The improved plasma uniformity and stability are achieved through the new structure, and the microwave efficiency is enhanced by introducing the focusing dielectric in the coupled cavity. Using a 3D electromagnetic field model, microwave plasma model and fluid model, the paper optimizes the geometry and inlet mode of the MPT device. Experimental results show that the novel MPT device can generate a plasma torch with a maximum height of 545 mm, a working range of 10−95 L/min, and a microwave efficiency up to 86%. The proposed device not only competently meets industrial requirements, but... [more]
Development of a Design Method for Casing and Tubing Strings under Complex Alternating Loads
Jianjun Wang, Dening Li, Xu Du, Hongjie Li, Shangyu Yang
November 30, 2023 (v1)
Keywords: casing, oil and gas well, pipe string design, tubing
With the escalating intricacy of downhole operational scenarios, encompassing frequent well cycling, acidification, multi-stage fracturing, steam injection, and intensive extraction, the efficacy of traditional casing-string-design methods rooted in strength considerations is progressively unveiling its limitations. Henceforth, it becomes imperative to establish string-design method standards that embrace the entirety of a well’s lifecycle, encompassing the phases of drilling, completion, fracturing, and production operations. Beginning with an analysis of the advantages and limitations of traditional casing-string-design methods, this paper introduces the features of strain and sealing design methods developed for the full lifecycle of the string. The strain design method, a departure from conventional design philosophies, enables the design concept of the controllable deformation of the pipe string. The sealing design method currently stands as the sole standard method for the design... [more]
Separation of VOC Gaseous Mixtures Using an Adsorption−Desorption Device
Ľudmila Gabrišová, Oliver Macho, Martin Juriga, Zuzana Gábrišová, Ivan Valent, Juraj Kabát, Jaroslav Blaško, Róbert Kubinec
November 30, 2023 (v1)
Keywords: Adsorption, desorption, Ethanol, granulated activated carbon, stripping
The aim of this work was to separate ethanol in an experimental adsorption−desorption device. We focused on concentrating ethanol by adsorption onto granulated activated carbon in its gaseous phase, which was produced by stripping a matrix with different ethanol concentrations (2, 5, 10, and 15% v/v). For adsorption, three kinds of granulated activated carbon (GAC) were used, marked as GAC1, GAC2, and GAC3. The separation product had a higher ethanol concentration than the initial ethanol concentration before the adsorption−desorption process. The enrichment factor was, in the case of the initial ethanol concentration, 2% v/v at the level of 10. With our new adsorption−desorption device, it is possible to achieve a product with an ethanol concentration of 59.0% v/v with stripping, adsorption, desorption, and condensation. To verify the separation efficiency, a real matrix (fermentation broth) was used. The ethanol concentration in the real matrix was, at the beginning of the separation... [more]
Structural Design and Preparation Process Research of Stacked MEMS Gas Sensors for Volatile Organic Compound Gases
Guizhou Wu, Junfeng Wu, Juan Dong, Xinyu Zhang
November 30, 2023 (v1)
Keywords: gas sensitivity characteristics, MEMS gas sensor, porphyrin zinc, volatile organic compounds
To design gas sensors with fast response speed and high sensitivity for the detection of volatile organic compounds, a stacked MEMS sensor was designed in this study. It utilizes porphyrin-sensitive materials and carbon nanotubes to form composite materials, improve the thermal stability of sensitive materials, and conduct sensor gas sensitivity testing. The results show that the design of the thermal insulation structure makes the sensor obtain lower power consumption and more uniform temperature distribution, and the maximum deformation variable is 3.7 × 10−2 μM. Doping carbon nanotubes in porphyrin-sensitive materials can effectively improve their thermal stability, and the sensor is in a safe state at temperatures below 358 °C. The sensor with higher response recovery characteristics at a low concentration of 80 ppm aniline has better response recovery characteristics, with a response time of 33 s and a recovery time of 23 s, respectively; its response recovery characteristics to 1... [more]
Optimal capacity design of amine-based onboard CO2 capture systems considering flexible ship operations
Juyoung Oh, Donghoi Kim, Simon Roussanaly, Rahul Anantharaman, youngsub Lim
October 18, 2023 (v1)
Keywords: MEA-based CO2 capture process, Off-design performance, Onboard carbon capture, Ship engine load profile, Techno-economic assessment
The International Maritime Organization has adopted a strategy aiming for net-zero greenhouse gas emissions from international shipping, prompting various mitigation technologies to comply with this strengthened strategy. Carbon capture technologies are increasingly being considered to satisfy the IMO strategy. In particular, amine-based carbon capture technologies, which are emerging as the most mature option, have been proposed for onboard application. However, the conventional design approach for onboard carbon capture systems, which assumes a fixed high engine load (75–100%), does not reflect flexible ship operation in a low engine load range, consequently leading to oversizing and unnecessary capital investment.
This study designs five MEA-based onboard carbon capture systems with different capacities (sizes) based on the exhaust gas conditions. The study investigates the off-design performance over the entire engine load range while maintaining the capacity of the capture syste... [more]
Comprehensive Review of Safety Studies in Process Industrial Systems: Concepts, Progress, and Main Research Topics
Jialu Zhang, Haojie Ren, Hao Ren, Yi Chai, Zhaodong Liu, Xiaojun Liang
September 21, 2023 (v1)
Keywords: process industrial systems, research review, research topics, safety, safety assessment
This paper focuses on reviewing past progress in the advancement of definitions, methods, and models for safety analysis and assessment of process industrial systems and highlighting the main research topics. Based on the analysis of the knowledge with respect to process safety, the review covers the fact that the entire system does not have the ability to produce casualties, health deterioration, and other accidents, which ultimately cause human life threats and health damage. And, according to the comparison between safety and reliability, when a system is in an unreliable state, it must be in an unsafe state. Related works show that the main organizations and regulations are developed and grouped together, and these are also outlined in the literature. The progress and current research topics of the methods and models have been summarized and discussed in the analysis and assessment of safety for process industrial systems, which mainly illustrate that the dynamic operational safety... [more]
Effect of Self-Recirculating Casing Treatment on the Aerodynamic Performance of Ultra-High-Pressure-Ratio Centrifugal Compressors
Tengbo Fan, Baotong Wang, Chuanxiang Yan, Wenchao Zhang, Zhaoyun Song, Xinqian Zheng
September 21, 2023 (v1)
Keywords: aerodynamic stability, centrifugal compressor, multi-splitter blade, parametric model, self-recirculating casing treatment, ultra-high pressure ratio
The motivation to design a more efficient and compact aircraft engine leads to a continuous increase in overall pressure ratio and decrease in the stage number in compressors. Compared to the traditional multi-stage compressor, a single-stage ultra-high-pressure-ratio centrifugal compressor with a pressure ratio higher than 10.0 can significantly improve the engine’s power-to-weight ratio and fuel economy with a reduced structure complexity. Thus, it has great potential to be adopted in the compression system of advanced aero engines, such as turboshaft engines, in the future. However, the highly narrow Stable Flow Range (SFR) of ultra-high-pressure-ratio centrifugal compressors is a severe restriction for engineering applications. This research focuses on the aerodynamic performance of a ultra-high-pressure-ratio centrifugal compressor, and three-dimensional simulation is employed to investigate the effect of Self-Recirculating Casing Treatment (SRCT) on the performance and stability... [more]
Intelligent Optimization Design of Distillation Columns Using Surrogate Models Based on GA-BP
Lixiao Ye, Nan Zhang, Guanghui Li, Dungang Gu, Jiaqi Lu, Yuhang Lou
September 21, 2023 (v1)
Keywords: BP neural network, distillation column, Genetic Algorithm, intelligent design, life cycle assessment, surrogate modeling
The design of distillation columns significantly impacts the economy, energy consumption, and environment of chemical processes. However, optimizing the design of distillation columns is a very challenging problem. In order to develop an intelligent technique to obtain the best design solution, improve design efficiency, and minimize reliance on experience in the design process, a design methodology based on the GA-BP model is proposed in this paper. Firstly, a distillation column surrogate model is established using the back propagation neural network technique based on the training data from the rigorous simulation, which covers all possible changes in feed conditions, operating conditions, and design parameters. The essence of this step is to turn the distillation design process from model-driven to data-driven. Secondly, the model takes the minimum TAC as the objective function and performs the optimization search using a Genetic Algorithm to obtain the design solution with the min... [more]
Model-Based Optimization of Multi-Stage Nanofiltration Using the Solution-Diffusion−Electromigration Model
Tobias Hubach, Stefan Schlüter, Christoph Held
September 21, 2023 (v1)
Keywords: ion permeances, lithium, magnesium, membrane separation, Modelling, Optimization, process design, solution-diffusion–electromigration
Nanofiltration is well suited to separate monovalent ions from multivalent ions, such as the separation of Li+ and Mg2+ from seawater, a potential lithium source for the production of lithium-ion batteries. To the best of our knowledge, there is no existing work on the optimization of a multi-stage membrane plant that differentiates between different ions and that is based on a validated transport model. This study presents a method for modeling predefined membrane interconnections using discretization along the membrane length and across the membrane thickness. The solution-diffusion−electromigration model was used as the transport model in a fundamental membrane flowsheet, and the model was employed to optimize a given flowsheet with a flexible objective function. The methodology was evaluated for three distinct separation tasks, and optimized operating points were found. These show that permeances and feed concentrations might cause negative rejections and positive rejections (espec... [more]
Techno-Economic Considerations on Nanocellulose’s Future Progress: A Short Review
Giannis Penloglou, Aikaterini Basna, Alexandros Pavlou, Costas Kiparissides
September 20, 2023 (v1)
Keywords: bacterial nanocellulose (BNC), lignocellulosic biomass, nanocellulose, nanocrystalline cellulose (NCC), nanofibrillated cellulose (NFC), production cost, Technoeconomic Analysis
Nanocellulose (NC) is an emerging natural material that offers great potential for various applications due to its unique properties and renewable character. Nowadays, as NC production technologies are advancing, it is essential to evaluate their economic feasibility, technological maturity and commercialization potential using systematic techno-economic analysis (TEA). The present study considers both technical and economic aspects of NC production and analyzes them in two ways: first, by developing a new concept based on the production of different types of NC through the conversion of lignocellulosic biomass by chemical and mechanical technologies, and second, by a comparative review of existing TEA studies in the open literature. Three specific scenarios and two case studies are evaluated by comparing specific key performance indicators (KPIs), such as the production cost (PC) and minimum product selling price (MPSP) of NC. As a result, a short though comprehensive overview of the... [more]
Three-Dimensional Analysis of the Flow Characteristics Induced by a Cubic Artificial Reef with Diversions
Haiying Mao, Ziyi Wang, Cong Hu, Kairui Wang
September 20, 2023 (v1)
Keywords: cubic artificial reef with diversion, cut-opening ratio, flow characteristics, flow velocity, three-dimensional analysis
In this paper, the flow characteristics induced by a cubic artificial reef with diversions (DCAR) were investigated using computational fluid dynamics (CFD). The results showed that the design of a DCAR can greatly improve the flow field range compared to typical cubic artificial reefs. The upwelling volume of the DCAR was more than 16 times that of a typical cubic artificial reef. The flow field effect produced the best results when the cut-opening ratio (COR) was 0.1−0.2 with constant flow. The parameters of the upwelling and back vortex increased with an increase in the flow velocity, and it decreased with an increase in the COR. The drag coefficient was less affected by the flow velocity, which remained between 1.32 and 1.44. The new type of artificial reef can improve the flow characteristics around the reefs.
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