The initial pyrolysis/de-volatilization step is common to all high-temperature gas-phase conversion processes (combustion, gasification and pyrolysis) of carbonaceous solids, because condensed phases do not react directly with the gas phase. The aim of the present work is to introduce a systematic, generic stoichiometric approach to represent a biomass starting material and the repartition of pyrolysis products. The approach transforms the conventional representation of the starting material, into a set of well-defined chemical species while respecting the atom balances. The starting points are the elemental composition of the dry and ash free matter of the biomass and the list of possible chemical species deriving from devolatilization. The algorithm is flexible and can accommodate a different selection of possible products. In the current implementation three product groups with 13 species are taken into account. Since there are infinite ways of splitting the starting material over the 13 components, at least 3 repartition coefficients and 8 atom relevance weights must be specified. The algorithm has been implemented using LIBPF (LIBrary for Process Flowsheeting), a process flow-sheeting and modeling tool arranged as a C++ library.
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Process modelling can be arranged as a domain-specific information model on top of OPC Unified Architecture, the new platform-independent standard for interoperability between enterprise information systems and industrial automation. With this technology model-based soft-sensors can be implemented as components in a Service Oriented Architecture, with the option to discover, set-up, configure and schedule the models from within the control system maintenance user interface.
In this work a prototype implementation of a first-principle soft sensor is presented, wrapped as an OPC UA Server. That soft-sensor calculates water and natural gas properties based respectively on the IAPWS-95 and GERG-2004 equations of state.
The thermodynamic calculations are implemented using LIBPF (LIBrary for Process Flowsheeting), a process flowsheeting and modelling tool arranged as a C++ library. The object-oriented design and portability of the LIBPF library fits perfectly with the philosophy of OPC UA, allowing for reduced development time and an extremely lean implementation. The soft sensor can be deployed either in embedded devices or as a server daemon/service.
]]>Currently one of the key challenges for the process industries is to react quickly to market changes; also the process automation and information technology infrastructure should follow seamlessly these changes without requiring frequent reconfiguration or manual adaptation of custom interfaces.
This driver for flexibility also applies to the model-based applications in use in the chemical, petrochemical and polymer industries: soft-sensors, inferentials, reconciliation, model predictive control and operator training systems. It is widely recognized that a Service-Oriented Architecture can match these requirements; in particular the recently released OPC Unified Architecture (OPC UA) specification provides a service-oriented architecture for interoperability in industrial automation.
In this work the prototype implementation of a simple process model as an OPC UA Server is presented; the model is a first-principle soft sensor that calculates a few useful physical properties from the composition of a process stream measured for example by a process gas-chromatograph.
The prototype demonstrates that an OPC UA soft sensor can be self contained, performant, transparent and easy to configure. Furthermore OPC UA is a very general technology that can be used to interface process models with other software components and implement distributed simulation systems; in this sense it challenges the existing interoperability standard CAPE-OPEN.
]]>June 2nd 2010, LIBPF 0.9 was released, 20 months after release 0.8. The key improvements are:
To know more, have a look at the What's new in LIBPF 0.9 document or download one of the LIBPF demos, which have all been updated to the new release.
The roadmap has also been updated to reflect these achievements and plan the capabilities up to revision 1.0, planned for March 2011.
Two new sections, Process Library (which replaces the Demo download area) and blog have been added.
The graphical skin has been redesigned with a cleaner look.
Preprint is available here. Final publication can be downloaded from the journal here.
IGCC (Integrated Gasification Combined Cycle) power plants look promising for the environmentally-friendly, large-scale production of electrical energy from low-cost fossil feedstocks such as coal or refinery residues.
In IGCC plants hydrogen is an intermediate product, as a syngas component, between the thermochemical section and the power section, which is a conventional combined cycle modified to handle this low-density fuel.
Replacing the conventional power section with a fuel cell, the IGFC (Integrated Gasification Fuel Cell) configuration promises lower emissions, higher efficiency and possibility to scale down to smaller sizes.
To explore the challenges and the feasibility of such an integration we have proposed putting a pilot-scale fuel cell system into operation within an existing, conventional IGCC, creating a hybrid fuel-cell-IGCC. Two innovative configurations have been proposed and optimized for a pilot-scale MCFC-GT (Molten Carbonate Fuel Cell – Gas Turbine) system, based on a typical syngas for IGCC plants such as that in operation at ISAB Energy Srl. The system has been modelled using the LIBPF process simulation library.
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LIBPF UI, targeted to a wider audience of model users, is now localized for a total 12 languages.
]]>A preprint is available here. The article is available online here and through this link if you have a subscription to the Journal.
The steady-state model of a Molten Carbonate Fuel Cell (MCFC) energy plant can be formulated with differing degrees of detail and implemented within any of the frameworks available today, but it is difficult to obtain an efficient, lean, robust simulation tool also capable of providing sensitivities. If such a tool were available, there would be much to gain in applying it online to support the operation of these plants.
In this paper we present a new system simulation tool for MCFC energy plants, based on a simplified model and implemented with the general purpose C++ process simulation library LIBPF.
We have tested our approach for an application example based on a reference hybrid 1 MWel MCFC-gas turbine energy plant. With the new tool it proved possible to analyse off-line the degrees of freedom when all operational constraints are considered, and to study the system part-load behaviour. The tool is also suitable for integration in an on-line application.
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Today September 22nd 2008, LIBPF 0.8 was released, 7 months after release 0.7. The key improvements are:
To know more, have a look at the What's new in LIBPF 0.8 document or download one of the LIBPF demos, which have all been updated to the new release.
The roadmap has also been updated to reflect these achievements and plan the capabilities up to revision 1.0, planned for August 2009.
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ODF 1.0 is the Open Document Format for Office Applications as defined by OASIS (Organization for the Advancement of Structured Information Standards) in the OpenDocument Specification v1.0 or equivalently ISO/IEC 26300:2006. It is natively supported by the three major productivity suites:
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| OpenOffice | Sun Microsystems |
IBM Lotus Symphony |
The Microsoft Office suite should include native support for ODF with the release of Microsoft Office 2007 Service Pack 2 (SP2) scheduled for the first half of 2009. At the moment support for ODF file format within the Microsoft Office suite can be achieved either using the Microsoft-backed OpenXML/ODF Translator Add-in for Office (Office 2007, 2003, XP) or Sun ODF Plugin for Microsoft Office (Office 2007 SP1, 2003, XP and 2000).
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With LIBPF 0.8, released on September 22nd 2008, the Database connectivity options for LIBPF expand beyond LIBPF ODBC, to cover SQLite, a public domain embedded transactional SQL database engine.
The new driver becomes available as a new product, LIBPF SQLITE.
To know more about the planned capabilities of LIBPF, check out the roadmap document!
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