Process Simulation Tools Research Articles

SIMULATION-DRIVEN DEVELOPMENT FOR COARSE COMMINUTION PROCESS - A CASE STUDY OF GEITA GOLD MINE, TANZANIA USING PLANTSMITH PROCESS SIMULATOR

AbstractA comminution process is a material size reduction and separation process which is primarily used in the aggregates and the minerals processing industry. Knowledge related to equipment’s operation, raw material properties, operational strategies, control system, maintenance, etc. is needed to design a capable plant. New needs are arising from the industry for existing operational crushing plants such as investigation for improvements, upscaling, and downscaling of the capacity. The paper presents an application of simulation-driven development for a crushing plant in an existing gold processing plant. Due to the change in ore characteristics and the need for optimizing the cost of operation, it is required to investigate the opportunities for improvement and alternative options for downscaling the capacity of the plant. A systematic process for configuring, developing, and evaluating alternative concepts using a process simulation tool is presented. The results show the process of generating knowledge for alternative crushing plant operation settings and how the choices can be selected and eliminated using boundary conditions. The evaluation presents possible improvements and alternative concepts with their opportunities and pitfalls.

Constructed Wetlands as Unit Operations in Chemical Process Design: Benefits and Simulation

Sustainability requires chemical processes to respect ecological constraints. Toward meeting this requirement, the idea of including ecosystems as unit operations in process design has been introduced in previous work. To make this idea more practical, this work develops a constructed wetland (CW) simulation module for use in the process simulation tool CHEMCAD. By simulating various combinations of an anaerobic bioreactor (ABR) technology and a CW ecosystem for water treatment, this work shows that CW is most cost-effective if adequate land area is available. Otherwise, a series arrangement with the ABR before the CW makes the most sense. This result introduces a potential design heuristic that technology is better suited than a nature-based solution for a higher concentration of waste. Integrated designs show that cost-effective designs reduce the separation load on distillation by relying more on the lower-cost CW. Recycling water makes economic sense only if the cost of water increases.

The role of process engineering in the digital transformation

The process engineering discipline has been largely excluded from Digital Transformation trends. The objective of this paper is to provide an overview of the obstacles to Digital Transformation for the process discipline and explain how these can be overcome. A special emphasis will be given on the role of the process simulation tool (white box modeling) as a catalyst for transformational change.The paper will examine several challenges specific to process engineering:1) Process simulators are divided into single-purpose point solutions. Separate models may be created for process design, control strategy design, operator training simulation, performance monitoring and online optimization.2) Process simulators are typically poorly integrated into engineering workflows beyond the process world, and if so, with a single directional information flow.3) Legacy process simulators are overloaded with niche features and functions only usable by experts.Industry stakeholders see the Digital Twin as the most important building block for Digital Transformation of the process industries. While legacy simulators are well-suited to accurately simulate processes, their decades-old architectures mean they are not ideal to serve the entire plant lifecycle and support the Digital Transformation. We will use the AVEVA Process Simulation as an example of how the identified obstacles can be overcome with a next generation process simulator.

Comparative analysis of absorption, membrane, and hybrid technologies for CO2 recovery

The implementation of hybrid systems for carbon dioxide (CO2) capture has been studied by several researchers in recent years. Systems based on the combination of membrane and absorption with amines technologies are the ones that have attracted more interest as industrial applications. In this work, a parametric sensitivity analysis was performed on the hybrid system (membrane and absorption with amines), and on each technology separately, in order to evaluate the most relevant operating variables of each system. Then, the energy requirements and greenhouse gases emissions (GHG) were estimated using process simulation tools. A natural gas stream with a concentration higher than 20 mol% of CO2 was used as feed. This stream was considered the feed of the three different treatment systems: two membrane systems, an absorption system with amines, and a hybrid system (membranes and amines). In the case of the membrane systems, a single-stage and two-stage arrangements were considered, using the total area of membrane as the response variable under analysis. The results showed that the single membrane area module requires around 2700 m2, while the two-module system allowed a 28% reduction in the total area. Amine inlet flows on the separation performance in the amine system were studied, determining a minimum value of 322.54 m3/h of diethanolamine (DEA) at 30% w/w. The hybrid process required a membrane area of 400 m2 and an amine flow of 123.25 m3/h to meet gas sale specifications. Considering energy requirements and carbon emissions, the hybrid system showed the best results among the analyzed technologies. The specifications were reached by showing low energy costs and carbon emissions and an acid gas stream with appropriate purity for enhanced oil recovery (EOR) and other applications.

A user workflow for combining process simulation and pinch analysis considering ecological factors

Abstract This paper aims to develop an innovative and practical method to accelerate Pinch Analysis problems using a combination of process integration, process simulation tools, and life cycle assessment techniques to design effective industrial energy efficiency measures rapidly. Data extraction and analysis is accelerated using the workflow, reducing pinch analysis duration, and therefore cost. This lowers financial barriers and is expected to help facilitate an increase in the number of conducted pinch analyses each year. An innovative ecological targeting step has been included in the workflow, which represents the option for end-users to further their CO2 savings, once energy targeting has been completed on a purely cost basis. It is expected that optimizing for costs first will enable the implementation of heat recovery solutions in industry. The methodology is applied to an example case study, and the learnings from industrial application is reported.

On the origin of start-up effects in ply-ply friction for UD fiber-reinforced thermoplastics in melt

Hot press forming is an attractive production technology to fulfil the increasing demand for complex fiber-reinforced thermoplastic parts. Over the years, process simulation tools on press forming have shown to be very helpful in facilitating the design stage for defect free parts production. One of the important deformation mechanisms considered in process simulations is the relative slip of successive plies or ply-ply friction, of which the underlying principles need to be better understood in order to improve the overall predictive simulation quality. In particular the use of steady-state friction values, neglecting the transient response, is questionable as experiments showed that shear stress overshoots can be as high as three times the long-time value. The phenomenon of the overshoot at start-up shear is analyzed. Possible explanations include nonlinear viscoelasticity and a slip relaxation effect giving rise to wall slip, which are discussed using relevant ply-ply friction measurements carried out on a dedicated friction test set-up. Experimental results on UD C/PEEK show that the shear stress build up and subsequent relaxation comply with nonlinear viscoelasticity. However, the long-time shear stress fails to match the matrix material’s viscosity, possibly due to a yield stress. The flow curve corrected for a yield stress resembles the effects of wall slip. A transient model according to these findings will enhance the accuracy of press forming simulation software.

Numerical prediction of process-dependent properties of high-performance Ti6Al4 in LS-DYNA

In modern manufacturing processes such as hot forming or additive manufacturing, the workpiece material undergoes very complex thermomechanical load cycles. The local mechanical properties in the component are process-dependent and the result of the different micro-structure evolution mechanisms in the material. Numerical process simulation tools aim to include more and more of these mechanisms in order to improve the accuracy of the simulations. The mechanical strength of high-performance materials such as Ti-6Al-4V depends on microstructural parameters, which are influenced by the temperature and strain histories. This contribution puts forward an implementation of a new generalized internal variables material model *MAT_GENERALIZED_PHASECHANGE in LS-DYNA. The evolution of internal variables such as phase fractions, grain size and dislocation densities can be predicted by evolution equations, and combined with yield stress models taking the contribution of the phases, grain sizes (Hall-Petch effect), and the dislocation density into account to predict the resulting mechanical properties of the processed material. The benefits of the implementation in the commercial software LS-DYNA is the possibility to solve complex coupled problems. For example, the new material law can be used to simulate hybrid manufacturing processes like forging and an additional additive manufacturing process, where changes in microstructure are highly coupled and important for the part properties.

Intra-ply shear characterization of unidirectional fiber reinforced thermoplastic tape using the bias extension method

Press forming of thermoplastic unidirectional (UD) carbon fiber reinforced laminates is an attractive production method in the aerospace industry for cost-effective manufacturing of high-performance parts. The possible formation of wrinkling defects in the formed parts has led to the development of predictive, finite element based, process simulation tools. The material behavior during the forming process is described based on the governing deformation mechanisms, being intra-ply shear, inter-ply and tool-ply slippage and bending. Intra-ply shear is especially important when forming parts having double curvature. The intra-ply shear behavior of fabric-based composite materials is often characterized using the bias extension method but has not successfully been applied to thermoplastic UD tapes yet. This work describes the application of bias extension experiments on cross-ply UD laminates at forming conditions to characterize the intra-ply shear material behavior. The test procedure was designed to prevent deconsolidation and improve load introduction, promoting specimen integrity and reduce shear buckling during testing. Preliminary results show that the material exhibits rate-dependent behavior. A video extensometer was used to measure the shear deformation in the center of the specimen. Additionally, a deformation analysis was performed using a grid of lines on the specimen, where the theoretical areas of constant shear according to a pin-jointed net can be recognized but are not fully uniform. In particular, shear banding parallel to the fiber direction is observed on the outer ply at a length scale below the grid size used for the deformation analysis suggesting a yield point and softening behavior on the meso scale which is not directly evident from the macroscopic response.

Regeneration units for thermolytic salts applications in water & power production: State of the art, experimental and modelling assessment

Thermolytic solutions are often proposed as high salinity or “draw” stream to generate a chemical potential driving force in Salinity Gradient Power (SGP) and Forward Osmosis (FO) technologies. Depleted “draw” solutions exiting the process can be regenerated by a thermal process powered at very-low grade heat, which is able to decompose the salt into gaseous ammonia and carbon dioxide, which can be stripped and then reabsorbed in the draw solution, restoring its initial concentration. In this work, two different experimental prototypes for the regeneration of ammonium bicarbonate aqueous solution were designed, built and tested. The effect of several operating parameters on the regeneration efficiency was experimentally investigated also identifying technological limitations and relevant solutions. A process simulation tool has been developed, and for the first time in the literature, successfully validated against original experimental results. Results from modelling analysis suggest that among the investigated processes, only the vapour stripping is viable for such applications. Models were used to evaluate the performance of ideal forward osmosis desalination and ideal SGP heat engines, finding, in the case of forward osmosis desalination, specific thermal consumptions between 180 and 250 kWh/m3 and, in the case of SGP heat engines, exergy efficiency up to almost 5%.

Impact of heavy ion particle strike induced single event transients on conventional and π-Gate AlGaN/GaN HEMTs

This paper presents an extensive Victory TCAD based assessment to evaluate the device performance under heavy ion particle strike induced single event effects (SEEs). The impact of SEEs on π-shaped AlGaN/GaN HEMT architecture has been compared with conventional AlGaN/GaN HEMT. For validation of simulation, models have been calibrated against the experimental data of in-house fabricated GaN HEMTs on SiC wafers, after which π-shaped architecture is realized using Silvaco’s Victory Process simulation tools. Comparisons demonstrate that π-Gate HEMT architecture is a SEE hardened device under different heavy ion particle strike conditions. Further, due to the step modification in the electric field itself, the π-Gate HEMT also exhibits SEE hardened operation under different ambient temperatures. The effect of angled heavy ion particle strike has also been studied for evaluating the device performance with regards to SEE.

Process Design and Sustainable Development—A European Perspective

This paper describes the state of the art and future opportunities for process design and sustainable development. In the Introduction, the main global megatrends and the European Union’s response to two of them, the European Green Deal, are presented. The organization of professionals in the field, their conferences, and their publications support the two topics. A brief analysis of the published documents in the two most popular databases shows that the environmental dimension predominates, followed by the economic one, while the social pillar of sustainable development is undervalued. The main design tools for sustainability are described. As an important practical case, the European chemical and process industries are analyzed, and their achievements in sustainable development are highlighted; in particular, their strategies are presented in more detail. The conclusions cover the most urgent future development areas of (i) process industries and carbon capture with utilization or storage; (ii) process analysis, simulation, synthesis, and optimization tools, and (iii) zero waste, circular economy, and resource efficiency. While these developments are essential, more profound changes will be needed in the coming decades, such as shifting away from growth with changes in habits, lifestyles, and business models. Lifelong education for sustainable development will play a very important role in the growth of democracy and happiness instead of consumerism and neoliberalism.

Life Cycle Management of the 3D-printer Technology to Design an Underwater Drone Hull to Study the Arctic

The paper deals with life cycle management of a 3-D printer technology to design an underwater drone hull to study the Arctic. The Arctic region is of strategic importance for the Russian Federation and the entire world community. Due to harsh climatic conditions the scientists started to search for more efficient ways of not only using resources of the territory but also retaining sustainable development of the region. The paper presents a graph that includes activities involved in a 3-D printer life cycle design. A 3-D printer is used for a layer growth of an underwater drone’s hull. The authors took into consideration all the existing options of development, operation and disposal of a particular 3D printer and identified eight variants of its life cycle design based on various financial resources and timing budgets. The study helped to identify a number of effective options. Information and mathematical systems support the implementation of the life cycle management of technology. We selected the following mathematical tools: mathematical programming methods, mathematical statistics, process simulation tools, routine problems, queuing theories. The paper focuses on such information management tools as systems programs, development programs and application software.

Steam System Load Shedding Operational Analysis Using Dynamics Simulation of a Fertilizer Plant

Steam system operation of a fertilizer plant can be complex due to high number of equipment, unavailable redundancy of steam suppliers and inter-dependency behaviour between steam users. The plant is subjected to partial or total shutdown whenever one boiler trips as both existing boilers are operating close to design capacity. Installation of an additional boiler will provide additional capacity margin in the event of one boiler trips. iCON(Symmetry) was used as the dynamic process simulation tool to establish proper management for load shedding activity with three boilers in operation. Model was developed for the integrated steam header, fuel gas and boiler feed water network. A detailed representation of the actual plant was achieved by incorporating plant hydraulics based on actual piping configurations, high fidelity equipment modelling, process control configurations, trip sequencing and operator manual interventions. This approach gives high accuracy in replicating the plant’s transient behaviour for load shedding case studies. The case studies prove the three boiler arrangement is able to sustain the plant’s continuous operation. An operational strategy was developed to minimize the impact of equipment trips. It is recommended to expand the model to include the process side to represent the actual plant behaviour with higher accuracy.

Numerical investigation of 660 MW pulverized coal-fired supercritical power plant retrofitted to oxy-coal combustion

A detailed investigation of the oxy-fuel combustion-based CCS consisting of air separation unit (ASU), supercritical boiler parameters and CO2 compression and purification unit (CPU) has been performed. A 660 MW supercritical power plant retrofitted to oxy-coal combustion has been simulated and analysed to investigate the operational characteristics of the oxy-coal combustion process by employing the process simulation tool Aspen plus. Moreover, the effect of important design parameters such as oxygen concentration of the oxidant, recycle ratio and purity of oxygen produced by ASU on the composition of flue gas, auxiliary power consumptions, CO2 recovery rate, CO2 product purity, and specific energy consumptions of O2 and CO2 has also been studied. The comparison of simulation results of the oxy-coal combustion and conventional air-fired combustion atmosphere has been presented. The excellent performance of oxy-coal combustion power plant has been observed in term of its ability to capture carbon dioxide with 95 % purity and 96 % recovery rate. The net efficiency of oxy-coal combustion power plant reduces by 10.4 % compared to the convention air-fired power plant.

Biomass to Liquids (BtL) Process Simulation, Economics and Environmental Impact Assessment for a 3000 bbl/d Plant

The biomass to liquids process (BtL) is an interesting path to produce synthetic petroleum via biomass gasification and Fischer Tropsch (FT) synthesis. The scope of this work is to describe, to simulate and to assess the economic and the environmental impact of the BtL multistep process. The process simulation tool is CheOpe, the economics have been estimated via Aspen Process Economic Analyzer V7.2.1 and the environmental assessment via GaBi V6.0. In this study, cobalt-based catalyst kinetics are simulated in a FT slurry bubble column reactor. The feedstock for FT is the syngas obtained from biomass gasification. The first step is a syngas reforming followed by a water gas shift (WGS) section to adjust the H2 to CO ratio to about 2 (required for FT catalysis) and then by a Rectisol® island to remove the acid gases (H2S, poison for FT catalysis, and CO2, inert gas in FT reaction). Finally, after the FT reaction section, the last step is the upgrading (UPG) of FT products to produce diesel and naphtha. An estimation of CAPEX for a 3000 bbl/d capacity plant has been carried out. Estimated investment costs are about M€ 400. This result has been paired with a life cycle assessment (LCA) in order to complete a decisional frame. LCA points out the environmental advantages in the use of BtL-fuels in the reduction of CO2 global emissions, if compared to the ones relevant to fossil fuels. This result respects the recent EU Directives limits.

The feasibility of utilizing existing process streams in kraft pulp mills as a source of chemicals for lignin extraction

Lignin is a sustainable raw material with a high potential for use in the production of renewable products. While the market for lignin is slowly growing, lignin recovery via acid precipitation during the kraft pulping process requires the addition of chemicals that will impact the chemical balance of the pulp mill. This negatively affects both the environmental and business operations. Utilizing existing process streams as a source of chemicals will allow the mill to close the chemical loop and reduce emissions, which will have positive environmental impacts. This study investigated the internal production of sulphuric acid (H2SO4) and carbon dioxide (CO2) for use in lignin separation (also called extraction) at a Swedish kraft pulp mill. The process simulation tool CHEMCAD was used to model and analyze the wet gas H2SO4 (WSA) process to produce H2SO4. The chemical absorption process using monoethanolamine (MEA) to capturing CO2 was also analyzed. The utilization of the sulphur-containing gases to produce H2SO4 can generate an amount that corresponds to a significant lignin extraction rate. The CO2 available in the flue gases from a mill well exceeds the amount required for lignin extraction.

Using in silico process simulation tools in pharmacy education: Considerations for pivoting to online learning

The COVID-19 pandemic has required identification of pharmaceutical learning content and teaching methods which can support attainment of learning outcomes through online delivery. In silico, or computer based, process simulations are ideal tools for incorporation into online programme elements, however the scaffolding of learning with in silico tools requires a structured approach. A previously developed face-to-face workshop, which used in vitro and in silico dissolution testing, was pivoted to an online learning element using an in-house dissolution simulation programme. The learning element was developed through trial and evaluation of experiences of novice, competent and expert user(s). The delivery of the learning element was planned to address three stages of simulation learning according to the Belton model, with accompanying tools developed to aid scaffolding and assessment of competency milestones. The proposed delivery and assessment is suitable for both synchronous and asynchronous learning, and is suitable for incorporation into an Advanced Pharmaceutics module.

Process modeling and optimization for biomass steam-gasification employing response surface methodology

This paper presents a process modeling and optimization study about steam-gasification of biomass. The gasification model is developed using Aspen Plus process simulation tool, and rice husk is considered as biomass fuel. Simulation results were validated with reported experimental results. The effects of the critical parameters, namely, steam-to-biomass ratio (S/B) and gasification temperature on the quality of the product gas as well as the gasifier cold-gas efficiency were analyzed. Response surface methodology (RSM) is employed to understand the synchronized effects of the critical decision parameters and thus to determine the optimized zone of operating condition. The study reveals that steam gasification can yield relatively clean, H2-rich (up to 58%, dry basis) product gas and the RSM analysis suggests that optimum performance is obtained for gasification temperature in the range of 750–900 °C and S/B in the range of 0.70–0.81, when the cold gas efficiency (CGE) approaches 90% and yields dry gas LHV of 12 MJ/kg and more.

Modeling oasis dynamics driven by ecological water diversion and implications for oasis restoration in arid endorheic basins

To achieve sustainable development, ecological water diversion has been implemented as a management tool to recover degraded oasis ecosystems in arid endorheic basins. Aiming to explore oasis response and identify appropriate objectives for oasis restoration, this study used a conceptual lumped ecohydrological model. Qingtu Oasis in the Shiyang River basin, Northwest China, was used as a case study to test this model. The model coupled groundwater budget, oasis response, and evapotranspiration dynamic modules. The model structure was clear and reasonable, and the calculation was of low cost. The application in Qingtu Oasis verified the model's effectiveness. The model was able to effectively capture the ecohydrological response attributed to the recovering of Qingtu Oasis in response to ecological water diversions occurring during the last decade. Combined with scenario analysis, the simulation indicated that Qingtu Oasis was fragile and largely dependent on ecological water diversion. Ecological responses were positive and non-linearly correlated with water input, resulting in an optimal water input that produced maximum water benefit by minimum water consumption. The ideal point method was useful in identifying this cost-effective water volume for oasis restoration. For Qingtu Oasis, the optimal water diversion was 45 million m3, which would recover the oasis to 29.16 km2 with an NDVI of 0.41. The current oasis conditions approach the optimal status, and ecological water diversion was suggested to continue and maintain the current oasis status. The volume of 45 million m3 could be taken as an upper threshold of water diversion, because above this threshold, water consumption would not result in water benefits effectively. This study proposed a practical tool for ecohydrological process simulation.

Process Modeling Issues in the Design of a Continuous‐Flow Process for the Production of Ibuprofen

AbstractThe continuous‐flow production of active pharmaceutical ingredients is a spreading applicative research field. Process simulation tools are effective means for in silico process design, but care is needed. A paradigmatic example is the synthesis of ibuprofen. First, the most appropriate thermodynamic models must be selected. The rich databases now available to collect thermodynamic properties are often insufficient because unconventional molecules are usually part of the recipe or found as intermediates or products. Furthermore, in some reaction steps ionic properties may be needed rather than those of the neutral molecules. All these points need a careful optimization of the methods for the estimation of the properties, with possible huge discrepancies of the results.