1,721,266 research outputs found
Design of a General Architecture for the integration of Process Engineering Simulation and Computational Fluid Dynamics
No full textPhD Dissertatio
Understanding the dynamic behaviour of middle-vessel continuous distillation columns
No full textThe fundamental dynamic behaviour of a middle-vessel continuous distillation column is studied in this paper. The interaction between
the middle vessel (MV) design and control parameters is identified by means of a linear analysis. Transfer functions relating the dynamics
of the product composition responses to changes in the disturbance inputs and manipulated inputs are derived. The role of the MV holdup
and MV level controller gain in altering the product composition responses is identified. It is shown that the MV level controller gain can
significantly affect the control performance when feed flow disturbances must be compensated for. However, it has a much lower impact
in the control performance when feed composition disturbances need to be rejected; in this case, exploiting the “buffering” effect of the
MV is more important for control. The analysis is carried out in detail for a LV control configuration, and is subsequently extended to an
“on-demand” DB configuration. Finally, simple guidelines for the choice of the MV level controller gain and MV holdup are provided
Interactions between Design and Control for Middle-Vessel Continuous Distillation Columns
No full textOptimizing the Design of Supply Chains for Carbon Capture, Utilization, and Sequestration in Europe: A Preliminary Assessment
Full text linkCarbon capture and storage represents a key technology for reducing the anthropogenic emissions of greenhouse gases. In addition to this, carbon utilization has often been considered as a viable option for increasing the environmental benefits, while decreasing costs of the mere capture and storage system. This contribution proposes
an optimization framework for the design of carbon capture, transport, utilization, and storage supply chains in the European context. Based on literature data, technologies converting CO2 into methanol and polyether carbonate polyols were selected as the most promising and incorporated into the optimization framework. The goal is to reduce
50% of European emissions from large stationary sources by 2030. Results highlight that, under our assumptions, the significance of carbon utilization in terms of a reduction of the environmental impact is likely to be a minor one: considering the current state of technologies only about 2.4% of the overall CO2 emitted from large stationary sources
can be removed by chemical utilization. However, significant benefits can be obtained in terms of overall cost reduction thanks to revenues deriving from the chemicals being produced
A General Methodology for Hybrid Multizonal/CFD Models: Part II: Automatic Zoning
No full textMultizonal models and, in particular hybrid multizonal/CFD models, represent a powerful approach to process simulation when complex
physical and chemical phenomena (e.g. crystallisation, polymerisation, bioreactions) need describing by taking into account mixing and
other fluid flow properties. A major issue in setting up such models is the definition of a suitable network of zones. This paper addresses
this issue by delivering some criteria to establish a suitable network of zones. The suggested procedure will be compared by means of a
mixing example
A Techno-Economical Comparison between two Technologies for Bioethanol Production from Lignocellulose
No full textThe conversion of biomass into biofuels can reduce the strategic vulnerability of petroleum-based transportation systems. Bioethanol has received considerable attention over the last years as a fuel extender or even as a neat liquid fuel. Lignocellulosic materials are very attractive substrates for the production of bioethanol because of their low cost and
their great potential availability. Two different process alternatives (i.e. the enzymatic hydrolysis and fermentation process and the gasification and fermentation process) for the
production of fuel ethanol from lignocellulosic feedstock are considered and analysed.
After a rigorous mass and energy balance, design optimisation is carried out. Both processes are assessed in terms of ethanol yield and power generation as well as from a financial point of view. A sensitivity analysis on critical parameters of the processes productivity and profitability is performed
Strategic optimisation of biomass-based energy supply chains for sustainable mobility
No full textThe identification of alternative and sustainable energy sources has been one of the fundamental research goals of the last two decades, and the transport sector plays a key role in this challenge. Electric cars and biofuel fed vehicles may contribute to tackle this formidable issue. According to this perspective, a multi-echelon supply chain is here investigated considering biomass cultivation, transport, conversion into bioethanol or bioelectricity, distribution, and final usage in alternative bifuel (ethanol and petrol) and electric vehicles. Multiperiod and spatially explicit features are introduced in a Mixed Integer Linear Programming (MILP) modelling framework where economic (in terms of Net Present Value) and environmental (in terms of Greenhouse Gases emissions) objectives are simultaneously taken into account. The first and second generation bioethanol production supply chain is matched with a biopower production supply chain assessing multiple technologies. Both corn grain and stover are considered as biomass sources. In the environmental analysis, the impact on emissions caused by indirect Land Use Change (iLUC) effects is also assessed. Results will show the efficacy of the methodology at providing stakeholders with a quantitative tool to optimise the economic and environmental performance of different supply chain configurations
Spatially explicit multi-objective optimization for the strategic design of first and second generation biorefineries including carbon and water footprints
No full textBiofuels production has been promoted in the attempt to address global warming and oil dependence concerns.
However, the environmental impact of biofuels is a very complex issue and cannot be represented by GHG (greenhouse gas)
emissions only (carbon footprint). In particular, water consumption (water footprint) has been recognized as a key issue in
renewable fuels production. This paper proposes a multiobjective Mixed Integer Linear Programming modeling framework to
optimize the environmental (i.e., the carbon and water footprints) and economic performances of bioethanol supply chains.
Multiechelon, multiperiod, and spatially explicit features are embedded within the formulation to steer decisions and investments
through a global approach. The strategic design and planning of corn- and stover-based bioethanol production networks is taken
into account. A case study is presented referring to the emerging Italian ethanol production. Results show the effectiveness of
mathematical programming-based tools to provide decision makers with a quantitative analysis assessing the economic and
environmental performances of different design configurations
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