Comparison of steady state and integral dynamic data reconciliation

Abstract This paper is devoted to the comparison of the performance of integral approach to dynamic data reconciliation and steady state data reconciliation. It is shown that in the absence of biases and leaks, the performance of both approaches is similar. Moreover, it is proven that once the appropriate variance is chosen, both methods are identical in the absence of accumulation terms. Finally, an analysis is made on how large the discrepancies are when there are accumulation terms

MILP approach for then design of vertical vapor-liquid separation vessels-comparison with heuristics

In this article we compare results from different heuristics approaches for the design of VLE separation vessels. In addition, we present an MILP approach that embeds the aforementioned heuristics and considers the discrete nature of the geometric variables. We show that different heuristics render different results and, while results from heuristics and MILP often coincide, significant departures occur.Fil: Fischer, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Desarrollo y Diseño. Universidad Tecnológica Nacional. Facultad Regional Santa Fe. Instituto de Desarrollo y Diseño; ArgentinaFil: Costa, André Hemerly L.. Universidade do Estado de Rio do Janeiro; BrasilFil: Bagajewicz, Miguel J.. Oklahoma State University; Estados Unido

Design of non-isothermal Process Water Networks

Abstract Despite the fact that many methods have been developed for the optimization of process water networks, solving the problem simultaneously considering heat recovery has rarely been addressed. This paper presents a new approach for the simultaneous synthesis and optimization of heat integrated water networks. The procedure is based on mixed integer non-linear mathematical programming (MINLP). A new superstructure for heat exchanger network (HEN) synthesis capable of exploiting unique features of water networks, like non-isothermal mixing of different streams, thus providing potentially more cost-effective solutions, is proposed. An example is presented to illustrate the synthesis of heat integrated water networks using the proposed approach

On the Integration of Process and Product Design with Microeconomics and Finances. Enpromer 2005

Abstract. In this paper the on-going process of integration of tools from process and product design with concepts of microeconomics and finances is discussed. The paper focuses in two such integrations. It is first shown that financial risk considerations can alter the decisions made in a project or in process operations. Then it is shown that some parameters that used to be considered data by PSE models, such as price, should be considered as variables, in some cases, first stage (“here and now”) variables and that they have an influence in the technical and operational decisions. Finally, a multi-scale/multi-model for new product design is presented, claiming that consumer behavior should be modeled

Studies on Hot Gas H₂S Removal Sorbents in Fixed-Bed Reactors at High Temperatures

Experimental and theoretical studies in the field of fuel gas desulfurization at high temperatures are presented. The performance of different oxides as sorbents for high temperature H2S removal is evaluated. A fixed-bed microreactor was used for this purpose. Basically, streams containing different H2S concentrations were passed through the reactor and the outlet H2S concentration was measured as a function of time. Comparisons between observed and theoretical maximum conversion values are used as a measure of sorbent H2S removal efficiencies. Most of the work was devoted to study zinc oxide and vanadium oxide, but other sorbents were also investigated. ZnO was studied because of its high equilibrium constant for sulfidation. High surface alumina-supported ZnO and high surface bulk ZnO were tested. Alumina-supported ZnO proved to have a smaller desulfurization capacity than bulk ZnO. In the case of V2O5, chemisorption of H2S on reduced vanadium oxide, rather than bulk sulfide formation, was found to be the mechanism of sulfur removal. Adsorption-desorption measurements were carried out in this case to investigate the behavior of the sorbent. The regeneration step, which restores the oxide by means of oxidation of the spent sulfide, was also studied in detail. The rate of ZnS oxidation was measured using a thermogravimetric analyzer. For the range of temperatures 650-700°C, the rate of reaction was consistent with Langmuir kinetics. The activation energy and the free energy of oxygen chemisorption were determined. An undesirable side reaction during oxidative regeneration is sulfate formation. The kinetics of this reaction was also investigated by thermogravimetric measurements. Theoretical studies dealing with reaction and diffusion processes in pellets and fixed-bed reactors were conducted, to a large extent motivated by the need to describe desulfurization processes. One chapter is devoted to a survey of exact and approximate solutions for an isothermal fixed-bed gas-solid reactor. Approximate analytical solutions to a class of models of reaction and diffusion inside sorbent pellets are presented next. The last chapter is devoted to a traveling wave solution describing reaction fronts inside non-isothermal fixed-bed reactors. This provides a good analytical approach for the prediction of conditions for the formation of zinc sulfate during the regeneration of ZnS.</p

ON THE ROLE OF MICROECONOMICS, MULTISCALE PLANNING AND FINANCES IN PRODUCT DESIGN (+) Corresponding Author. Keywords: Product Design.

In this article it is claimed that in order to obtain the right composition, structure and/or functionality for a new product, one needs to anticipate what the demand of the product will be and take into account all costs involved (associated manufacturing and supply chain). To obtain the demand, one needs a pricing model, which in turn relies on consumer preferences that are connected to the product composition, structure and/or functionality. Thus, a multi-scale model, including the varying characteristics of the product, the manufacturing capacity and site, the supply chain and ultimately, the markets, is proposed. We use a very simple case of insect repellent to illustrate how the best repellent, identified as the one that consumers will prefer the most, is not the most profitable one and how one can obtain the insect repellent composition that maximizes profit.