Advanced Process Simulation Research Articles

Characterization and modeling of an epoxy vitrimer based on disulfide exchange for wet filament winding applications

AbstractThe present paper investigates the suitability of a vitrimeric epoxy resin for processing in the wet filament winding (WFW) process to manufacture fiber‐reinforced polymers (FRP). Comprehensive material characterization of a commercially available epoxy and vitrimeric resin based on disulfide exchange is carried out, and the processing in WFW is evaluated by analyzing thermomechanical, rheological, thermochemical properties, and chemical shrinkage. The direct comparison of a vitrimer and an established epoxy resin permits an indication of the processability and necessary adjustments in WFW. Based on the implications of modeling, we demonstrate the processing of the vitrimeric resin in the WFW process by increasing the resin bath temperatures. The vitrimer's and conventional resin's elastic modulus development and compression behavior were similar, highlighting the vitrimeric resin's potential. Further, the results confirm that established characterization and modeling routines can be transferred to vitrimeric resins and, therefore, path the way toward advanced process simulation of vitrimeric resin's processing. For this, the present publication gives essential advice for setting up testing schedules for characterizing epoxy vitrimers' processing behavior and their appropriate modeling. The present work underlines the potential of applying commercially available dynamic hardeners to manufacture recyclable and malleable FRP in established processes.Highlights Material characterization and modeling of wet filament winding process. Wet filament winding of epoxy vitrimers. Thermomechanical and chemical shrinkage characterization of epoxy vitrimers. Rheological and kinetic modeling of epoxy vitrimer.

Design modification and comparative analysis of glycol‐based natural gas dehydration plant

AbstractNatural gas production from reservoirs is often associated with water, which poses numerous challenges, such as methane hydrate formation, sludge, corrosion and flow assurance issues in gas processing plants and sales gas transmission pipelines. To effectively remove water from natural gas, there is a need to design, compare and modify dehydration plants. This study investigated the performance difference between a conventional triethylene glycol (TEG)‐based dehydration system with a cooler at the TEG inlet to the contactor, and a newly proposed TEG‐based dehydration system with a heat exchanger replacing the cooler at the TEG inlet with the contactor. The advanced process simulation software Aspen HYSYS was used to design and compare two dehydration system configurations. The modified design configuration exhibited better performance in terms of energy conservation and water‐removal capability. The material balance of molar flow, mass flow and volume flow of dry gas produced in the absorber/contactor column showed a higher volume of dry gas produced in the modified system configuration, indicating that it is a better design. The modified design configuration also produced dry gas within the recommended temperature range for underground storage and transmission. There was a significant difference in the percentage difference of 64% between the conventional and modified designs in terms of energy consumption, whereas the percentage differences of 0% and 0.6% showed nonsignificant and significant differences between the two plant design configurations. Both plant design configurations showed a significant reduction (from 0.005 to 0.0002 mol%) in the water composition of natural gas after the simulation.

Solar-Assisted Carbon Capture Process Integrated with a Natural Gas Combined Cycle (NGCC) Power Plant—A Simulation-Based Study

In the realm of Natural Gas Combined Cycle (NGCC) power plants, it is crucial to prioritize the mitigation of CO2 emissions to ensure environmental sustainability. The integration of post-combustion carbon capture technologies plays a pivotal role in mitigating greenhouse gas emissions enhancing the NGCC’s environmental profile by minimizing its carbon footprint. This research paper presents a comprehensive investigation into the integration of solar thermal energy into the Besmaya Natural Gas Combined Cycle (NGCC) power plant, located in Baghdad, Iraq. Leveraging advanced process simulation and modeling techniques employing Aspen Plus software, the study aims to evaluate the performance and feasibility of augmenting the existing NGCC facility with solar assistance for post-carbon capture. The primary objective of this research is to conduct a thorough simulation of the Besmaya NGCC power plant under its current operational conditions, thereby establishing a baseline for subsequent analyses. Subsequently, a solar-assisted post-combustion capture (PCC) plant is simulated and seamlessly integrated into the existing power infrastructure. To accurately estimate solar thermal power potential at the Baghdad coordinates, the System Advisor Model (SAM) is employed. The integration of solar thermal energy into the NGCC power plant is meticulously examined, and the resulting hybrid system’s technical viability and performance metrics are rigorously evaluated. The paper contributes to the field by providing valuable insights into the technical feasibility and potential benefits of incorporating solar thermal energy into conventional natural gas power generation infrastructure, particularly in the context of the Besmaya NGCC plant in Baghdad. The power generation capacity of the plant was set at 750 MW. With this capacity, the annual CO2 generation was estimated at 2,119,318 tonnes/year which was reduced to 18,064 tonnes/year (a 99% reduction). The findings aim to inform future decisions in the pursuit of sustainable and efficient energy solutions, addressing both environmental concerns and energy security in the region.

Data-driven recurrent neural networks modeling of cyanobacteria growth in bubble columns reactors under sparging with CO2-enriched Air

Cultivating carbohydrate-enriched microalgae in photobioreactors is a recognized method for converting atmospheric carbon dioxide (CO2) into valuable resources, offering a solution to combat industrial CO2 emissions. Achieving global carbon neutrality by 2050 necessitates an annual reduction of approximately 1.4 gigatons of CO2. To address this challenge, we developed a machine learning-based black box model using data from the Institute of Advanced Materials for Sustainable Manufacturing at ITESM. This dataset encompasses hourly operational parameters collected over eleven months, including temperature, pressure, and flow rate. These parameters were essential for a microalgal cultivation experiment using the cyanobacterium Desertifilum tharense and CO2-enriched air. Two 100-L photobioreactor systems were employed. Leveraging the sequential dataset, we deployed a long short-term memory network (LSTM) to predict CO2 percentages at reactor outlets, indirectly indicating algae biomass production. Seven input variables were selected on the basis of their impact on system behavior. Using advanced machine learning time series mathematical models can boost process intensification tasks through advanced process optimization, simulation, and control goals.

Simulation Of The Optimum Operating Conditions For A Propylene Glycol Production Unit Using Aspen Hysys Software

Commercially, propylene glycol is produced by the direct hydrolysis of propylene oxide with water. This first-order, irreversible, exothermic reaction is performed in a glass-lined Continuous Stirred Tank Reactor (CSTR). In this study, the initiation of a CSTR was modelled from first principles and simulated using Aspen Hysys 3.2 to obtain concentration and temperature profiles. It is often very important how these profiles approximate the steady-state values. For example, when approaching a steady state the temperature may rise too high and this leads to degradation of the reactant or product, or the altitude may be unacceptable for safe operation. If either condition occurs, the system will exceed its practical stability limit. The practical stability limit represents the temperature above which it is undesirable to operate due to undesirable side reactions or equipment damage. Therefore, the best-operating conditions were obtained in terms of the flow rate of the raw material and the temperature of the reactor at 345 Kgmol/h and 82.2 °C on straight. The production of propylene glycol in the presence of an acid catalyst in an isothermal tank reactor is presented using advanced process simulation software. The effect of temperature was also calculated using the principle of energy balance on the reactor. The reactor operates optimally at a fractional conversion of 0.995 to obtain optimal values for the most important variables/parameters [reactor volume 7.92 m3, reactor length 2.83 m, reactor diameter 1.89 m, and amount of heat required for cooling per unit volume of the reactor 1205 kw].

Simulation of Gas-Water Two-Phase Flow in Tight Gas Reservoirs Considering the Gas Slip Effect

A mathematical model for the gas-water two-phase flow in tight gas reservoirs is elaborated. The model can account for the gas slip effect, stress sensitivity, and high-speed non-Darcy factors. The related equations are solved in the framework of a finite element method. The results are validated against those obtained by using the commercial software CMG (Computer Modeling Group software for advanced recovery process simulation). It is shown that the proposed method is reliable. It can capture the fracture rejection characteristics of tight gas reservoirs better than the CMG. A sensitivity analysis of various control factors (initial water saturation, reservoir parameters, and fracturing parameters) affecting the production in tight gas wells is conducted accordingly. Finally, a series of theoretical arguments are provided for a rational and effective development/exploitation of tight sandstone gas reservoirs.

PROCESS DESIGN AND ECONOMIC ANALYSIS OF TRADITIONAL SHEA BUTTER PRODUCTION IN NIGERIA

The promotion of agricultural diversification emerges as a critical component of broader strategies aimed at mitigating greenhouse gas emissions and fostering the development of sustainable production systems. Nigeria stands out as a significant exporter of shea butter, which play a vital contribution to poverty alleviation, particularly in rural areas through creation of opportunities for participation of local women in the shea butter industry using local technologies in sheanuts pre-processing, roasting, grinding, oil extraction and refining. However, this production route is said to be severely affecting the final product yield and quality in addition to possible significant impacts on the environment. Evaluation of this production pathway is necessary for identification of areas of resource inefficiency, such as excessive utility (water, energy) consumption, implementation of more efficient and eco-friendly production processes. This study presents a process design and economic analysis of the local technology for shea butter production using advanced process simulation software (Aspen Plus ® V11) and Aspen economic analyser following 1 st quarter 2018 price basis. The simulation result showed that nearly 230 kg/day shea butter could be produced from 1 tonne shea fruit, which translate to only about 23 wt%. Pulp, shell and cake representing waste streams account for approximately 70 wt%. Utility analysis revealed daily water footprint of 585kg and 500 kJ heating requirement/day with carbon emission of 63 kgCO 2. The economic evaluations of the entire process plant showed that the traditional technology requires approximately $1.70M capital cost and $0.066M operating cost/year for 25-year economic life of the project with net present value of $158M. This study suggests that the local shea butter production technology is profitable with a payback period of 7years. However, the technology generates huge amount of waste streams and have negative impact on the environment. Consequently, there is need to adopt best practices in the shea butter processing that will generate more income and promote environmental sustainability.

A new power flow model for combined heat and electricity analysis in an integrated energy system

As one of the important approaches to take complementary advantages of heat and electricity, an integrated energy system with combined heat and power (CHP) units enables the coupling of electricity and heating networks, which markedly increases energy utilization efficiency. However, the different characteristics between heat and electricity bring a great challenge to realizing synergy and complementarity. In this paper, a thermal–hydraulic model is developed based on the analogy between heating and electricity networks to analyze the district heating network. Thereafter, a new electricity-heat coupling model with matrix formulation, also known as the coupled power flow model, is proposed to realize the combined calculation of heat and electricity in an integrated energy system. The thermal–hydraulic model is validated by simulation results obtained from Advanced Process Simulation Software (APROS) with relatively small errors. The validated coupled power flow model is further applied to conduct an optimization study to evaluate the integrated energy system efficiency considering wind power and heat storage. Optimization results show that the simultaneous addition of an electric boiler and a heat storage unit can reduce the total operating cost by 17.36%. The present study indicates that coupling calculation of heat and electricity can be achieved with the proposed power flow model, which is beneficial to the design and optimization of practical integrated energy systems.

Optimization of thermal performance of high temperature sensible heat thermal energy storage system for direct steam generation: A simulation work

The high temperature sensible heat thermal energy storage (TES) system for direct steam generation (DSG) has wide prospects in efficiently utilizing waste heat recovery. Improving the charging/discharging efficiency under a large working temperature range is one of the key issues in optimizing the high-temperature sensible heat TES system performance. This paper focuses on the optimal thermal performance of a high-temperature TES system for DSG by using solid graphite for high-temperature flue gas recovery in a gas turbine. The working performance of the high-temperature TES for DSG was simulated by APROS, which is a physics-based advanced dynamic process modeling and simulation software. The effects of the number and mass distribution of thermal storage cell units on the discharge efficiency were investigated. The results show that the effects of cell unit number on discharging efficiency can be neglected when the cell unit number reaches 10. Based on that, an optimized mass distribution based on the local enthalpy matched method was obtained, and the discharging efficiency can reach up to 0.665. Moreover, the thermal performance of the TES system during the charging and discharging process was also analyzed, especially the effects of flow distribution in parallel modules. Further, the performance of TES was analyzed by integrating it into the CCGT start-up process. The results show that the initial charging rate of TES has opposite effects on waiting time and system efficiency for the CCGT start-up process. And a proper initial charging rate for the start-up process of the CCGT system in this work is suggested to be 0.4.

Analysis of Manual Reactor Trip of NEK NPP in APROS Computer Code

The Slovenian Krško Nuclear Power Plant (NEK) model was built in using APROS - Advanced PROcess Simulation environment. The basis for the this model was the RELAP5/MOD3.3 Engineering Handbook, the model was updated to the 26th cycle and also includes the upflow conversion modification. A detailed model nodalisation was created for each system and every system was separately validated. The current model covers the primary circuit with the core kinetics model, the secondary circuit and their control systems. The steady state of the APROS NEK model already having been validated, the plan now is to validate the model for some transients and design basis accidents. In this article the plant behaviour after the manual reactor trip is analysed in detail. Two scenarios of the manual reactor trip transient are performed, where either the Main Steam Isolation Valve (MSIV) closes after 60s – case A, or remains open – case B. After the manual reactor trip from the 100% power, the control system signal actuations and their times were followed and then the responses of different affected systems were being observed. All those recorded values were then compared with the identical transient performed on the similar NEK model with the RELAP5/MOD3.3 system code. This procedure allowed to bring the current APROS NEK model one step forward towards being assured to have accurate calculations.

Advanced process simulation of compression molded carbon fiber sheet molding compound (C-SMC) parts in automotive series applications

The following paper focuses on the development of a 3D virtual process chain (VPC) for parts made from Carbon Fiber Sheet Molding Compounds (C-SMC). The VPC consists of two modules addressing the compression molding and warpage simulation of parts made from two different high fiber volume fraction C-SMC materials. The press simulation module applies a solid mechanics material modelling approach within the Coupled Eulerian-Lagrangian (CEL) simulation framework available in ABAQUS/Explicit. Through a combination of flow characterization experiments and numerical simulations, local mechanical properties and fiber orientation information can be predicted from numerically simulated local flow strains. A warpage simulation module has also been developed in ABAQUS/Standard together with a data processing/transfer interface implemented in ANSA. With these highly integrated numerical tools, process characteristics such as press forces, flow fronts and weld-line development based on material amount, insert geometry and placement position in the mold can all be predicted and analyzed.

Optimal Control of Combined-Cycle Power Plants: A Data-Enabled Predictive Control Perspective

In this work, we propose an optimal control strategy as the unit control for combined-cycle power generation units. Using the same optimal control, we propose to optimize other internal control structures. Data-Enabled Predictive Control is chosen as the optimal control problem formulation, as it does not require a parametric state-space representation of the system. This bypasses the challenging and expensive-to-solve issue of parametric modeling and linearization for highly nonlinear systems. The performance of the controller is investigated in several critical operational scenarios, such as load-following for frequency control and disturbance rejection. Simulation results in Apros®, which is an environment dedicated to advanced process simulation, are presented.

Process and device simulations aimed at improving the emitter region performance of silicon PERC solar cells

Achieved levels of silicon-based passivated emitter and rear cell (PERC) solar cells laboratory and module-level conversion efficiencies are still far from the theoretically achievable Auger limit of 29.4% for silicon solar cells, prominently due to emitter recombination and resistive losses. The emitter region in PERC devices is formed by using either ion implantation followed by a diffusion process or POCl3 diffusion. In ion-implanted emitter-based PERC, the process variables such as dose, energy, diffusion time, and temperature play a vital role in defining the characteristics of the emitter region. Detailed investigation of these parameters could provide a pathway to mitigate the recombination as well as resistive losses; however, it requires a considerable budget to optimize these parameters through a purely experimental approach. Therefore, advanced industrial standard process and device simulation are perceived in this work to carry out the comprehensive study of process variables. Investigation of ion implantation and diffusion process parameters on the PV performance of an upright pyramid textured, industrial standard stacked dielectric passivated PERC solar cell is carried out to deliver 22.8% conversion efficiency with improved PV parameters such as short circuit current density (J SC) of 40.8 mA cm−2, open-circuit voltage (V OC) of 686 mV, and fill-factor (FF) of 81.54% at optimized implantation and diffusion parameters, such as implantation dose of 5 × 1015 cm−2 with energy 30 keV followed 950 °C diffusion temperature and 30 min of diffusion time. The performance of the optimized PERC device is compared with already published large area screen printed contact-based device. This work may open up a window for the experimental work to understand the influence of process parameters on the emitter region to develop the highly efficient PERC solar cell in the future.

Dynamic Process Simulation of a Molten-Salt Energy Storage System

The main objective of this work was the construction of a numerical model using Advanced Process Simulation Software to represent the dynamic behaviour of a thermal storage system (TSS). The storage model was validated by comparing the results with the measured data of the storage process of the Andasol 2 solar power plant. Subsequently, a system analysis and system optimisation were carried out, and the stand-alone concept of the thermal storage system is presented. Stand-alone refers to an isolated use of the storage system without a solar power plant. During power peaks, this storage medium is heated with excess electrical power and later returned to the electrical grid through a steam cycle. Then, the system was optimised by modelling four models based on the type of storage medium and the temperature difference of the storage system. The four models, Andasol 2, SSalt max, Hitec, and Carbonate, were evaluated and compared in terms of the improvement in capacity and efficiency that can be achieved. The comparison shows that the preferred storage medium is carbonate salt due to the increases in both efficiency and capacity. The greatest increase in efficiency in terms of power generation can also be achieved with the Carbonate model (18.2%), whereas the amount of increase was 9.5% and 7.4% for each of SSalt max and Hitec, respectively. The goal of this analysis and system optimisation of a thermal salt storage system is to stabilise and relieve the local power grid.

A Comparison Study on the Improved Operation Strategy for a Parabolic trough Solar Power Plant in Spain

The present work focuses on the development of a detailed dynamic model of an existing parabolic trough solar power plant (PTSPP) in Spain. This work is the first attempt to analyse the dynamic interaction of all parts, including solar field (SF), thermal storage system (TSS) and power block (PB), and describes the heat transfer fluid (HTF) and steam/water paths in detail. Advanced control circuits, including drum level, economiser water bypass, attemperator and steam bypass controllers, are also included. The parabolic trough power plant is modelled using Advanced Process Simulation Software (APROS). An accurate description of control structures and operation strategy is necessary in order to achieve a reasonable dynamic response. This model would help to identify the best operation strategy due to DNI (direct normal irradiation) variations during the daytime. The operation strategy used in this model has also been shown to be effective compared to decisions made by operators on cloudy periods by improving power plant performance and increasing operating hours.

Design and Implementation of the Solar Field and Thermal Storage System Controllers for a Parabolic Trough Solar Power Plant

Dynamic simulation provides an efficient approach for improving the efficiency of parabolic trough power plants and control circuits. In the dynamic simulation, the possibilities and operating conditions of the plant are evaluated regarding materials, processes, emissions, or economics. Several studies related to the dynamic simulation of the parabolic trough technology are summarised and discussed in this work. This study is the first research that presents a thorough description of the advanced control circuits used in the solar field and thermal storage system of a parabolic trough power plant. This power plant was implemented using advanced process simulation software (APROS). The dynamic model was built based on the real specifications of the power plant.

An Investigation on High-Resolution Temperature Measurement in Precision Fly-Cutting.

The loads acting on a workpiece during machining processes determine the modification of the surface of the final workpiece and, thus, its functional properties. In this work, a method that uses thermocouples to measure the temperature in precision fly-cutting machining with high spatial and temporal resolution is presented. Experiments were conducted for various materials and machining parameters. We compare experimental measurement data with results from modern and advanced machining process simulation and find a good match between experimental and simulation results. Therefore, the simulation is validated by experimental data and can be used to calculate realistic internal loads of machining processes.

Enhancement of process modelling and simulation evaluation by deploying a test for assessment and feedback individualisation

This paper demonstrates a novel approach for a computer-based course assessment. A test is introduced in which computers are deployed. This significantly contributes to the enhancement of the marking consistency, individual performance distinction and feedbacks, and widen the questions range for computer-based modules. The proposed test method, for the first time, uses the simulation files marking for individualised evaluation purposes. The methodology has successfully been implemented in practice for three modules including Process Simulation (CE2105), Advanced Process Simulation (CE4023), and Process Computation (CE3021) at Aston University (UK) over three academic years, from 2016 to 2019. The effectiveness of the proposed approach has been evaluated using several factors, including final marks, consistency multiple academic years, and mark distribution. In contrast to the common teamwork assessments, individualised feedback became possible. While ASPEN has been used for CE4023 and CE2105 tests, MATLAB has been applied as the computation platform for CE3021 module. This reveals the applicability of different software in proposed methodology. The number of students in the cohorts studied was from 52 to 204, demonstrating the applicability of the method for various cohort sizes. Even though the methodology has been demonstrated based on the chemical engineering discipline modules, it allows digitalising the delivery and assessment of a wide range of simulation techniques in many disciplines.

Validation of the Moody and Henry–Fauske Critical Flow Models in apros Against Marviken Critical Flow Experiments

Abstract The Moody and Henry–Fauske critical flow models implemented in Advanced Process Simulation Software (apros) have been validated against Marviken critical flow experiments and compared with other available simulations of the same experiments. Both models in combination with discharge coefficient 0.75 (suggested for best estimate calculations) produce results close to the experimental data for two-phase flows, while one-phase flow of subcooled water is underpredicted. Using discharge coefficient 1.0 for subcooled water leads to a good match with the experimental results, while two-phase flows become overpredicted.

Operational Flexibility of a CFB Furnace during Fast Load Change—Experimental Measurements and Dynamic Model

The share of power from fluctuating renewable energies such as wind and solar is increasing due to the ongoing climate change. It is therefore essential to use technologies that can compensate for these fluctuations. Experiments at 1 MWth scale were carried out to evaluate the operational flexibility of a circulating fluidized bed (CFB) combustor during transient operation from 60% to 100% load. A typical load following sequence for fluctuating electricity generation/demand was reproduced experimentally by performing 4 load changes. The hydrodynamic condition after a load change depends on if the load change was in positive or negative direction due to the heat stored in the refractory/bed material at high loads and released when the load decreases. A 1.5D-process simulation model was created in the software APROS (Advanced Process Simulation) with the target of showing the specific characteristics of a CFB furnace during load following operation. The model was tuned with experimental data of a steady-state test point and validated with the load cycling tests. The simulation results show the key characteristics of CFB combustion with reasonable accuracy. Detailed experimental data is presented and a core-annulus approach for the modeling of the CFB furnace is used.