June 25th 2007 Paolo Greppi – UNIGE 1 of 24

Object-oriented modelling applied to hybrid unit

operationsPaolo Greppi, Barbara Bosio, Elisabetta Arato

Department of Civil Environmental Architectural EngineeringUniversità degli Studi di Genova

ICheaP-8 - The eight International Conference on Chemical & Process Engineering

ISCHIA Island Gulf of Naples, Italy - June 24-27th 2007

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Contents

� Introduction

� Streams, flashes, connectivity, multistage

arrangements

� Applications

� Conclusions

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Introduction: model workflow

LIBPF model

LIBRARY executable

library developer

model developer

model user

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mod

el

deve

lope

rlib

rary

de

velo

per

Model development

� pick up concrete classes from LIBPF� write a C++ program representing the

system model� compile it to a standalone executable

� map process simulation entities to � abstract C++ class types� mixins: reusable partial classes� concrete classes

LIBrary for Process Flowsheeting

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Model deploymentm

odel

us

er� receives system model as an executable� access via user interface� can change inputs or switch configuration� each model configuration has a fixed

structure

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Contents

��� IntroductionIntroductionIntroduction

� Streams, flashes, connectivity, multistage

arrangements

� Applications

� Conclusions

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The simplest object: stream

� abstract stream type

� specialized mixin classes are derived from abstract stream type

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Concrete stream types

� every concrete stream type contains at least one total phase

� multi-phase streams can have explicit representations of the phases

�stream_VLe...

�stream_VLLSSSe...

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Enter reactions

� Take a generic flash (genflash) mixin class

instance

� add reactions ...

� ... get reactive flashes

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Enter connectivitySpecial mixin types represent the capability of units to connect to streams

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Compose mixins ...connectivity

mixinprocess

mixin

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.. get a concrete class

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Variations of genflash with connectivity

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Combinations of generic flashes

� flexible mulstream concentrated parameters model: multihx

� N reactive streams exchanging heat or mass:� (reactive) multi-stream heat

exchanger

� (reactive) membrane unit

� fuel cell

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Multistage arrangements

� Concentrated parameter objects are combined to yield distributed parameter models:

� 1-D arrangements: �� columns columns

�� pipespipes

� 2-D arrangements:�� fuel cellsfuel cells

�� reactive heat exchangersreactive heat exchangers

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Contents

��� IntroductionIntroductionIntroduction

��� Streams, flashes, connectivity, multistage Streams, flashes, connectivity, multistage Streams, flashes, connectivity, multistage

arrangementsarrangementsarrangements

� Applications

� Conclusions

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Application 1: Simple distillation column

The column was broken down into 8 subunits:

2 multistage1D<genflashNX<stream_VL>>

3 genflashNX<stream_VL>

2 mixer

1 splitter

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Application 2: Distributed parameter planar Fuel Cell

� 5 x 10 multihx objects

� flowsheet for cross-flow arrangement

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Application 2: Distributed parameter planar Fuel Cell

� Results match proven tools

� Example: solid temperature plot for MCFC (Molten Carbonate Fuel Cell)

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Applications: simulation run duration

LIBPF slower than special-purpose tools

Benchmark LIBPFTiming, s Timing, s

Simple distillation column

Commercial process simulator X

1 10

Planar Fuel Cell

Special purpose 2-D finite differences code

2 60

Test caseReference tool (benchmark)

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Applications: modelling project durationmodelling of hybrid / complex unit operations

� conventional approach:

3 man-months

� new approach with model reuse:

1 man-month

(estimates)

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Contents

��� IntroductionIntroductionIntroduction

��� Streams, flashes, connectivity, multistage Streams, flashes, connectivity, multistage Streams, flashes, connectivity, multistage

arrangementsarrangementsarrangements

��� ApplicationsApplicationsApplications

� Conclusions

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Conclusions

� C++ can be used for process simulation using LIBPF library

� Run-time is slower than with conventional approaches ...

� ... but project duration is shorter for hybrid unit operations modelling

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Visit libpf.com

� Get C++ header files with the classes hierarchy

� Get and run demos

� Request the LIBPF library by mail