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EQE038 – Simulação e Otimização de Processos Químicos

Argimiro R. Secchi

– Aula 3 –

Advanced modeling capabilities in the EMSO model editor.

EQ/UFRJ

29 de agosto de 2014

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• Plug-ins – External Routines

• Termodynamics – VRTherm

• EML – Streams• IF-THEN-ELSE• Switching models

(switcher)• FOR

Other features in the modeling language

Other features in the modeling language

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Using External Routines - Plugins

EMSO is a simulator based on equations and its modeling language allows to directly express the equation of the equipment.

However, there are some cases that the description directly in the form of equations is not convenient, typical examples include:

Some parameters of the model require initialization procedures (routines);

The mathematical relationships require a high number of data;

The user already has its own routine calculations;

EMSO solution: plug-in system that allows any routine written in C, C++ or FORTRAN to be used within the models.

The plug-in interface is open, anyone can implement a new plug-in.

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Using the PluginsTo use an external procedure in the models the user needs to declare a special parameter called PluginPlugin::

Once the Plugin has been declared, the user can call its methods using the notation:

Before running a simulation, EMSO will check: If all methods used in the models were properly implemented in the plugin. If the number of arguments and the units of measure are correct.

Variable = Plugin.method(args)

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Rankine cycle: thermodynamic properties in FORTRAN 90

Example:

• Routine calculations developed by the user: Plugin propterm.dll

Using the Plugins

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Applying in a thermoelectric power plant

File: sample/water_steam/sample_power_plant.mso

Using the Plugins

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VRTherm – Methods

Main Thermodynamic

Models

Flash Calculation

Pure componentProperties

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Properties of mixtures

VRTherm – Methods

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The development of a basic material stream is the starting point for a library of models.

In order to made compatible with each other, the models created by many different people need to be directly connected.

That is, it should be possible the output calculated by a model be connected to the input of another model.

For this goal to be reached, all models should use standard streams, which enable integration of different models featuring a library.

Standard EML Streams

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InletInlet material streams should be of type streamstream

OutletOutlet material streams should be of type:

liquid_stream: liquid_stream: liquid phase

vapour_stream: vapour_stream: vapor phase

streamPH: streamPH: when the vaporized fraction of the stream is unknown. It made a flash calculation to determine the thermodynamic state of this stream.

Using EML Streams

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Example – Flash Model

Models/flash.mso

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Flash Steady – Simulation

Example: run the flowsheet of the file sample_flashPH.mso. The original problem is an adiabatic flash. Consider also the results specifying the pairs (T, P) and (T, Q) instead of (P, Q). Test the problem of calculating the feed temperature or feed pressure specifying T, P and Q.

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Distributed Models – Heat Exchanger

A heat exchanger may be represented by a system

formed by two ducts.

Description Description of the ductof the duct

Models/HeatExchanger.mso

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Heat Exchanger – Duct Modeling

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Aggregation in the heat exchanger

Heat Exchanger Modeling

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Using IF THEN ELSE END

Heat Exchanger Modeling

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Heat Exchanger – Distributed Model

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Heat Exchanger – Distributed Model

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Example: run the flowsheets HeatX and HeatX_Discretized in the file Sample_HeatExchanger.mso. Compare the temperature of the output stream. Export the results of the discrete to Excel or LibreOffice building the temperature profiles of the heat exchanger:

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0 1 2 3 4 5 6 7 8 9 10

Te

mp

era

tura

(K

)

T_hot (K)

T_cold (K)

Heat Exchanger – Simulation

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Switcher – textual parameters

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Decisions independent of the user's choice

Switcher – textual parameters

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Distributed Models– pipe model

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FOR commandVectors Matrices

Distributed Models– pipe model

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ExerciseExercise

1) Build a model of a pressure pan with a relief valve (with constant equal to 0.07 cm2) which opens when the pressure is greater than 5 times atmospheric pressure, and closes when less than four times this pressure. Consider a 5 L pan with 20 cm in diameter containing only water with an initial level of 10 cm and a temperature of 25 °C. The heating is done at a rate of 10 kW. Simulate the pan for 10 minutes. Consider the phases in thermodynamic equilibrium model and use the Peng-Robinson model.

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For helping in the preparation of this material

Special thanks to

For supporting the ALSOC Project.

Prof. Rafael de Pelegrini Soares, D.Sc.Prof. Rafael de Pelegrini Soares, D.Sc.Eng. Gerson Balbueno Bicca, M.Sc.Eng. Gerson Balbueno Bicca, M.Sc.Eng. Euclides Almeida Neto, D.Sc.Eng. Euclides Almeida Neto, D.Sc.Eng. Eduardo Moreira de Lemos, D.Sc.Eng. Eduardo Moreira de Lemos, D.Sc.Eng. Marco Antônio MüllerEng. Marco Antônio Müller

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... thank you for your attention!

Process Modeling, Simulation and Process Modeling, Simulation and Control LabControl Lab

• Prof. Argimiro Resende Secchi, D.Sc.Prof. Argimiro Resende Secchi, D.Sc.

• Phone: +55-21-2562-8307Phone: +55-21-2562-8307

• E-mail: arge@peq.coppe.ufrj.brE-mail: arge@peq.coppe.ufrj.br• http://www.peq.coppe.ufrj.br/Areas/Modelagem_e_simulacao.htmlhttp://www.peq.coppe.ufrj.br/Areas/Modelagem_e_simulacao.html

http://www.enq.ufrgs.br/alsoc

EP 2013

Solutions for Process Control and OptimizationSolutions for Process Control and Optimization