Process Simulation Techniques Research Articles

Production of phenolic and glucosinolate extracts from rocket salad by supercritical fluid extraction: Process design and cost benefits analysis

A profitability analysis of a large scale supercritical fluid extraction (SFE) process to obtain natural extracts from rocket salad is presented in this work. An industrial-scale SFE plant is designed using process simulation techniques based on experimental data. Afterward, the effect of operative parameters on the process costs is evaluated. At the optimum conditions, the economic and financial analysis is performed, and the influence of the price of rocket salad on the price of the natural extract is assessed. Results indicate that the raw materials account for 67% of the total production costs. The proposed industrial application could be economically viable with a pay-back period of 10years if the price of the rocket salad extract is larger than 21.9US$kg−1, considering the current wholesale price in the market, or 17.0US$kg−1 if using non-saleable rocket salad. Both scenarios make the process economically sustainable and competitive with the current price of natural extracts obtained by extraction with organic solvents.

Executable Closed-Loop Simulation Lifecycle Management Framework Incorporating Fault Detection Classification and Discrete Process Simulation

As contemporary manufacturing environments are getting more volatile and dynamic, many control frameworks and related information systems have been provided. Simulation Lifecycle Management is considered an advanced dynamic manufacturing framework with early warning control functionality among them. While other systems focus on fault detection and its classification, SLM reasons where the defects occur and how these are removed. This paper provides several executable control frameworks for achieving current manufacturing goals as well as for repairing defects. The suggested framework classifies the degree of defects and analyzes current production objectives with discrete process simulation techniques. Then, it generates the following-up schedule and modifies control parameters. The effectiveness of the provided control framework is proven with a numerical example.

도로공사 공정계획을 위한 공정 로직 및 건설장비 효율화 방안

Highway construction is a combination of linear, repetitive, and highly equipment intensive operations. Various types of construction equipment are deployed to ensure undisrupted performance of construction, and thus productivity improvement and cost-saving can be achieved through well-thought-out planning. The selection of construction equipment is dependent upon construction sequence, site conditions, and construction methods. In the process of planning, management should consider various types of construction methods per each type of construction operation. Also, management should map out proper construction equipment operation plan that takes the construction duration and cost measures into consideration. However, limited availability of historic data from the similar types of operations has been a stumbling block to proper construction planning, making the operations performed based upon experience and intuition guided by rules-of-thumb. As a consequence, the planing phase rarely provided an adequate validity in the implementation phase. The researchers developed a process logic for each construction type that management can utilize from early phase of highway construction planning process. Moreover, derived the construction equipment combination optimized for efficiency by using the process simulation technique. The developed method is expected to be useful for the decision-making process that aims to evaluate efficiency of various process plans and to ensure optimal selection of construction equipment for highway construction projects.

Performance improvement of a crude oil distillation unit

This study builds on an earlier investigation carried out on an existing crude oil distillation unit (CDU). The energy and exergy efficiencies of the plant are low and opportunity for plant improvement was established. The methodology adopted for improving the plant performance uses process simulation techniques, and the combined exergy and traditional retrofit methods to show what the process is capable of achieving under considerable expense on the required capital investment. The process improvement carried out resulted in the increase in the overall CDU energy and exergy efficiency by 4.0 and 1.6% respectively, reduction in emissions by 14.2% and savings in utility bill by $1.61 million per annum. The required capital investment for retrofits amounted to $3.78 million with a payback time of 2.35 years.

The Site Visualization and Closed-Loop Control for 3D Assembly Process

With the rapid development of 3D CAD technology, 3D assembly process is playing an important role in the on-site assembly. A closed-loop control method and three-dimensional site visualization technology site is presented. The methodology takes into account CAD design stage, assembly process design, site assembly and site inspection. The method includes three key technologies: the verification process technology of three-dimensional assembly process, optimization and process simulation techniques of site assembly, closed-loop control technology of assembly process quality inspection. Finally, the method and technology has applied in the actual assembly, and achieved good results.

Hybrid modeling and simulation for trustworthy software process management: a stakeholder‐oriented approach

SUMMARYProcess Management Model (PMM) and Process Simulation Model (PSM) are the critical infrastructural components of the Trustworthy Process Management Framework (TPMF), which involves a large and heterogeneous group of stakeholders in process modeling and simulation to improve process trustworthiness. Process Modeling Stakeholders (PMS) have different levels of dependency on various process modeling and simulation techniques. They may also possess different perspectives or concerns in modeling. To support trustworthy process management, this paper integrates the stakeholder‐oriented approach and hybrid simulation technique into software process modeling at three levels of abstraction (i.e., activity, sub‐process and system). The hybrid process simulation combines micro‐level discrete process models with the macro‐level continuous process models to capture process dynamics. In particular, the stakeholder‐oriented approach addresses the various perspectives of PMS during process modeling and simulation. Finally, a case study with a realistic process model demonstrates that this approach incrementally integrates stakeholders' modeling concerns through hybrid simulation, which is difficult to achieve using discrete or continuous modeling/simulation techniques independently. Copyright © 2010 John Wiley & Sons, Ltd.

The use of a virtual building design and construction model for developing an effective project concept in 5D environment

The growing diversity of disciplines, participants, tasks, tools and events associated with project management at the design and construction stages, the increasing pressure of costing competition and tighter production deadlines, as well as continually increasing quality requirements and the need for technological enhancements, are the driving force of information modeling and numerical simulation in the construction industry. When choosing the most effective investment project in construction, a major problem associated with the actual demand for resources is underestimated. In order to solve this problem in the most effective way, the application programs, covering virtually every phase of the specific construction product development, e.g. planning, design, cost estimation, scheduling, fabrication, construction, maintenance and facility management were developed and supplemented with the calculation of the demand for resources, comparison of alternatives and determination of the duration of all the stages of the project life. Theoretical principles and practical innovative applications of building information modeling and construction process simulation technique, used to determine the most effective alternative of the project by applying the appropriate multiple criteria evaluation methods, are considered in the article.

Exploring diverse process and team alternatives through virtual process simulation

PurposeThe purpose of this paper is to present a virtual process simulation technique for modeling process alternatives.Design/methodology/approachThe paper proposes modeling method and applies it to an illustrative example.FindingsThe method is effective in modeling the illustrative example and provides a method for studying team composition and dynamics a priori.Practical implicationsThe paper presents an approach to model process alternatives in order to select the best deployment option. The modeling process incorporates measures and metrics relating to global geographic and team issues. Incorporation of these issues affords the process designer the ability to predict more accurately the most successful deployment option.Originality/valueThe research contributes to the study of process modeling by examining the potentially neglected or ignored issues relating to geographic and team diversity.

Three-Dimensional Plasma Etching Simulation using Advanced Ray Tracing and Level Set Techniques

We present three-dimensional simulation techniques for plasma etching processes. Models based on Langmuir-type adsorption and on ballistic particle transport at feature scale can be efficiently solved in three dimensions. Surface coverages are self-consistently calculated. The local sputter rates of ions and the fluxes of neutrals are computed using modern ray tracing algorithms. In this way angle and energy dependent sputter yields or specular reflections of ions can be incorporated in a natural manner. For the time evolution of the surface we apply a recently developed fast multi-level-set framework. Our simulation techniques are demonstrated using a SF6/O2 plasma etching process model.

Applying Process Simulation Technique to Value Engineering Model: A Case Study of Hospital Building Project

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Applying value engineering (VE) in a construction project has proven to be an effective way to save the cost of a project. Different VE models have been developed and used in construction projects in the past. One common attribute of construction projects is the dependence of a highly qualitative decision making process: capturing, interpreting, and quantifying expert's subjective judgment. This study proposes an advanced five-phase VE model, each phase of which consists of a series of steps to better quantify subjective opinions of VE team members. Construction simulation technique, the Cyclic Operation Network, is used as a means to minimize subjectivity in estimating the value of different alternatives in terms of time and cost savings. A case study shows that the advanced five-phase VE model improves analysis, assessment, and decision on VE. This new approach has a great potential to minimize subjectivity during VE process and improves VE decision-making process by using quantitatively derived data from the simulation analysis. </para>

Optimal scheduling and operation of biodiesel plants with multiple feedstocks

Various feedstocks may be utilised to produce biodiesel. These include soybean, palm, sunflower, jatropha, rapeseed and safflower oils, as well as waste oil from the food industry. With changing prices, supply and demand of feedstocks, a need exists to consider various feedstocks options for biodiesel production. The objective of this work is to develop a systematic procedure for scheduling and operation of flexible biodiesel plants accommodating a variety of feedstocks. This work employs a holistic approach and a combination of process simulation, synthesis and integration techniques to provide: 1) process simulation of a biodiesel plant for various feedstocks, 2) integration of energy and mass resources, 3) optimisation of process design and scheduling, 4) techno-economic and environmental assessment and sensitivity analysis of proposed schemes. An optimisation formulation is developed to determine scheduling and operation for various feedstocks. A case study is solved to illustrate the merits of the devised procedure.

Life Cycle Assessment Coupled with Process Simulation under Uncertainty for Reduced Environmental Impact: Application to Phosphoric Acid Production

One of the most important drawbacks of life cycle assessment (LCA)-related analysis is the generation of reliable data. In the proposed methodology, this drawback is addressed using data from process simulations, based on first-principles models in the LCA calculations. Furthermore, uncertainty that arises from industrial data and a simulation hypothesis are explicitly incorporated, using Monte Carlo sampling, which allows statistical information to be translated into a set of representative scenarios for which the LCA calculations are performed. The combined use of LCA, process simulation, and sampling techniques results in a powerful environmentally conscious quantitative tool whose objective is to guide decision-makers toward the adoption of more-sustainable process alternatives. The main objective of the methodology is to show the main differences between production options. This novel methodology is applied to the specific case of phosphoric acid (PA) production.

Plant growth simulation for landscape-scale hydrological modelling

Landscape-scale hydrological models can be improved by incorporating realistic, process-oriented plant models for simulating crops, perennial grasses and woody species. The objective of this project was to present some approaches for plant modelling applicable to daily time step hydrological transport models, such as SWAT. Accurate simulation of plant growth can improve the accuracy of simulations of hydrological and biogeochemical cycles. First, we describe some unique aspects of the general plant model ALMANAC. Next, we describe a modification of the original ALMANAC model used to simulate complex successional vegetation changes in the years following disturbance of a variety of different forest ecosystems, such as forest fires, clear cuts and insect infestations. Finally, we discuss alternative physiological and physical process simulation techniques of plant growth that could increase simulation accuracy in landscape-scale hydrological and transport models such as SWAT.

The application of process modelling and simulation techniques to analysing the impact of CRM implementation

The ability to measure the impact of CRM implementation on the performance of an organisation is critical to executive decision-making. However, research suggests that most of the currently applied performance metrics are either not directly linked to the CRM activities or too broad. This paper presents an exploratory research that evaluates the potential impacts of changes to CRM activities at a case study company. By representing the CRM activities in a process format, the study was able to apply the technique of modelling and simulation to various options being considered by the organisation. The results of the simulation indicated that the existing process was inefficient when compared with two of the options being considered. It also indicated that in addition to efficiency gains, any investment in the proposed changes would be recovered through increased sales capacity.

A Generalized Optimization Tool ForManufacturing Processes

With the recent advances in many areas of manufacturing process simulation, numerical optimization techniques can be used in every day decision making for different products. Decisions in an industrial setting are usually made to meet the desired objectives within a priority structure starting from the higher to the lower goals. In addition, most manufacturing process simulation techniques require a high level of nonlinear mathematical modeling. To address the high level of non-linearity and achieve an optimized setting for different manufacturing processes within the preset priority structure, Nonlinear Goal Programming multi-objective optimization models are the natural choice. This paper presents a nonlinear multi-objective optimization model that can be used in any industrial setting to optimize different manufacturing processes. The resulting nonlinear optimization problem is solved using zero order unconstrained optimization techniques. This reduces the effort required to model the metal forming process problem since linearization and gradients are not required. The optimum solution can also be achieved from any starting point, since feasibility conditions are not needed. The application and efficiency of the developed model is demonstrated for different manufacturing processes such as fixturing, metal forming, and metal cutting test cases.

Thermo‐Economic Modelling and Optimisation of Fuel Cell Systems

AbstractThis paper describes and illustrates the application of a methodology for thermo‐economic design and optimisation of fuel cell systems. This methodology combines the use of process simulation and process integration techniques to compute thermo‐economic performances of fuel cell systems that will be used in a multi‐objective optimisation framework. The method allows the generation of integrated fuel cell system configurations and their corresponding optimal operating conditions. It should be used as a preliminary design methodology, allowing the identification of promising system configurations, which would be further analysed. The methodology and the thermo‐economic models are described and demonstrated for the design of PEMFC hybrid systems, combining fuel cell and gas turbine technologies.

Design of a PCB plant with expert system and simulation approach

This paper presents a case study of using simulation in planning a new Printed Circuit Board (PCB) manufacturing system. The process simulation technique and expert system are proposed to evaluate the design alternatives and logistics management. Simulation results, such as machine utilisation, waiting time, and throughput of system are generated for evaluation. Simulation models were developed using software package SIMPROCESS, which is based on the concept of visual interactive simulation. Besides, the formation of the models is assisted by the expert system package VP-EXPERT. Each approach was found to accurately model the PCB manufacturing plant layout, provide operational and logistics performance in terms of throughput, waiting time, and resource utilisation, and provide a basis for suggesting the best modes of logistics operation.

Understanding management of computational process modeling and simulation

The use of computational process modeling and simulation has become widespread as the real cost of computers has decreased and their capabilities have increased. However, many science and engineering university faculties have failed to treat this area as a formal undergraduate discipline. The result has been generally a self-taught approach by professionals to both the practice and the management of modeling and simulation. This article describes process modeling and simulation techniques and applications.

Assessing the impact of e-Procurement strategies through the use of business process modelling and simulation techniques

In the last years, a strong disillusion has heavily affected many companies in the implementation of business to business (B2B) applications. These drawbacks are mainly due to the rushing adoption and acquisition of these new systems, believing that they would have acted as tools for automating processes, rather than real opportunities for modifying the business strategy. Their added value can be negligible and, paradoxically, negative, if not accompanied by a thorough revision of the decision-making activities and of the roles performed by the involved actors. Focusing on e-Procurement systems, this paper intends to demonstrate how the adoption of rigorous business process simulation methodologies enables analysts to properly map current and future processes and to evaluate the expected pay-offs resulting from the re-engineering activity. The paper analyses at first the main issues deriving from the new strategic role of the purchasing function. Then, it provides a literature review of the main business process modelling and simulation techniques, pointing out their role in e-Procurement projects. Finally, it introduces an industrial application experienced in a multinational pharmaceutical company and motivates how the use of business process simulation methodologies effectively supported the re-engineering process of the procurement division and the evaluation a priori of different possible solutions.

Planning gang formwork operations for building construction using simulations

Concrete formwork is a labor-intensive and time-consuming operation. Many modular formwork systems have been developed to automate the process. Such systems improve the productivity as well as the cost-effectiveness of the operation. However, proper planning for the form reuse schemes in the design as well as the construction phases of a building, including resource allocations (modular form sets, cranes, workers, etc.), and the construction sequence, is vital for ensuring a successful use of modular formwork systems. Computer process simulation techniques are employed in this research for the study of different form reuse schemes to use gang forming systems in building construction. Five form reuse schemes are identified. The CYCLONE modeling methodology is employed to develop computer models for each of them. MicroCYCLONE simulations and sensitivity analyses of the schemes, using different numbers of form sets, cranes, and labor crews, are then conducted for a real case to assess their impact on the productivity as well as the cost-effectiveness of the operation. The objective is to better understand the characteristics of different form reuse schemes and, in turn, to produce better plans for gang forming construction. Thus, the application of modular formwork systems in building construction can be facilitated.