Flowsheeting analysis tools

Flowsheeting analysis tools enable to get more value from the simulation results. The most used is the sensitivity analysis. This consists usually of recording the variation of some sampled variables as function of manipulated variables. The interpretation of results can be exploited directly, as trends, correlation or pre-optimisation. Case studies can be employed to investigate combinations (scenarios) of several flowsheet variables. Finally, the simulation work may be refined by multi-variable optimisation. 

In contrast to these generic tools, the second group of domain-specific software tools addresses certain tasks during the design process in the chemical engineering domain. They can roughly be classified as data retrieval, synthesis, and analysis tools. A typical example for data retrieval tools are physical property systems [1048, 1053[. Synthesis tools include flowsheet synthesis [951, 1039], plant layout and pipe routing [955], model development ]54, 558] or even solvent selection [7.37]. The most prominent examples of analysis tools are process simulators for steady-state ]518, 556, 1046] and dynamic simulation ]288, 518, 916]. 

A more advanced feature in flowsheeting is the use of analysis tools for design or operation. For example, a sensitivity analysis can capture interrelations between different variables in the simulation problem. A more elaborate research may involve case studies. The capacity of simulation to imagine virtual experiments is a real benefit from which the user should know to take full profit. 

The most critical aspect in simulation is the selection of appropriate thermodynamic models. Different models can be used on different parts of the flowsheet, or for some units. For example, equation of state model can be used for the whole flowsheet, but liquid activity models are more suitable for separations. The accuracy of model parameters should be checked systematically. Thermodynamic analysis tools should be used systematically to evaluate the accuracy of phase equilibria before detailed simulation of separations. 

The methodology presented hereafter regards a MIMO system that can be handled by a combination of multi SISO loops. It is an input/output controllability being based on linear analysis tools. It can be applied to a stand-alone complex unit, as a distillation column, or to a flowsheet. In this later case it has the character of a decentralised (integral) plantwide control problem. 

However, as we have demonstrated in our previous examples, this design is usually not the one that provides the best control, i.e., the least variability of product quality. What we need is a way to incorporate quantitatively (in terms of dollars/year) this variability into the economic calculations. We discuss in this section a method called the capacity-based approach that accomplishes this objective. It should be emphasized that the method provides an analysis tool, not a synthesis tool. It can provide a quantitative assessment of a proposed flowsheet or set of parameter values or even a proposed control structure. But it does not generate the besf flowsheet or parameter values it only evaluates proposed systems. 

Techno-economic Analysis Tools for Carbon Dioxide Capture and Reuse in Integrated Flowsheet... 

O R-MTBE-U Convergence Flowsheeting Options Model Analysis Tools EO Configuration Results Summary... 

The continuing decline in costs of graphical devices and the broadening availability of easy-to-use graphical software has made computer graphics a feasible tool in flowsheeting presentations and analysis (1 0 ). ... 

Within the database of the flowsheet editor, only prominent information about the flowsheet elements is stored, including characteristic parameters of process steps and equipment items as well as stream and piping information. This information needs to be shared for the development of further mathematical models inside modeling tools, the cost analysis of different process parts, as well as the specification of steady-state dynamic simulations in simulators. 

As final step, the results of the analysis, i.e. one or more models appropriate for representing the simulation, are delivered back to the tool that requested the extended situation analysis. In the scenario described here, the PRIME process fragment is then responsible to offer the model alternatives to the user, and to allow him or her to integrate them into the flowsheet as refinements of the separation block. 

Consequently, the software tools developed as part of IMPROVE were examined both analytically and empirically. Depending on the state of development of each software, one or more evaluation techniques were chosen, and by means of concrete examples of designing user interfaces, suggestions for a better configuration were acquired. In the following, we discuss the analysis and evaluation of the design support system EVA, of the flowsheet editor FBW (see also Subsect. 3.1.3), of the administration system AHEAD (see also Subsect. 3.4.2), and finally of the communication platform KomPaKt (see also Subsect. 3.3.2). 

The objective of this investigation was, therefore, (i) to assimilate flie rqipropriate plant data from various sources, (ii) to determine and estimate their accuracy, (iii) to calculate closed mass balances for defined intervals of time, and (iv) to develop quantitative model to predict the production of ZIC and its composition based on the feed materials and their analysis. In the course of the investigation, the mass balance model was developed first (Model 1) with the aid of data reconciliation. Then, the prediction model (Model 2) was calculated based on the results of Model 1 incorporating a multi-parametrical regression analysis, hi this paper, the capabilities of the combination of these two modem computer-aided tools will be demonstrated as applied to the Ruhr-Zink flowsheet. With these methods, a plant simulator can be updated in a relatively short time that incorporates the latest changes in the flowsheet. 

Analysis, or simulation, is the tool chemical engineers use to interpret process flowsheets, to locate malfunctions, and to predict the performance of processes. The heart of analysis is the mathematical model, a collection of equations that relate the process variables, such as stream temperature, pressure, flow rate, and composition, to surface area, valve settings, geometrical configuration, and so on. The steady-state simulators solve for the unknown variables, given the values of certain known quantities. 

Naot, I., and D.R. Lewin, Analysis of Process Dynamics in Recycle Systems Using Steady State Flowsheeting Tools, Proc. 4th IFAC Symposium on Dynamics and Control of Chemical Reactors, Distillation Columns and Batch Processes (DYCORD 95), Helsingor, Danish Automation Society, Copenhagen (1995). 

The RCM technique has been considered a powerful tool for the flowsheet development and preliminary design of conventional multicomponent, nonideal separation processes (Fien and Liu, 1994). It represents a good approximation to actual equilibrium behavior and allows the designer to perform feasibility analysis of separation processes where nonideal and azeotropic mixtures are involved. Traditionally, nonreactive residue curves have been used to predict the liquid-composition trajectories in continuous distillation... 

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