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- Integração de processos: a base de uma utilização energeticamente eficiente da Biomassa e a cooperação internacionalPublication . Cabrita, Isabel; Matos, Henrique A.
- Correction: Correia et al. Sustainability Assessment of 2G Bioethanol Production from Residual Lignocellulosic Biomass. Processes 2024, 12, 987Publication . Correia, Bárbara; Matos, Henrique A.; Lopes, Tiago; Marques, Susana; Gírio, FranciscoError in Table: In the original publication [1], there was a mistake in Table 8 as published. The presented cost of purchased equipment and Total CAPEX cost shall not differ between the two scenarios. The purchased equipment cost and Total CAPEX cost should be, for both scenarios, 21.35 and 75.66M€, respectively. The corrected Table 8 appears below. The authors state that the scientific conclusions are unaffected. This correction was approved by the Academic Editor. The original publication has also been updated.
- Sustainability Assessment of 2G Bioethanol Production from Residual Lignocellulosic BiomassPublication . Correia, Bárbara; Matos, Henrique A.; Lopes, Tiago; Marques, Susana; Gírio, FranciscoABSTRACT: The development of sustainable biofuels can help to reduce the reliance on fossil fuels and mitigate the impact of climate change. This study analyzes bioethanol production from agro-forestry residual biomass, namely eucalyptus residues and corn stover. The study includes process simulation using Aspen Plus software, followed by economic analysis and life cycle assessment (LCA) with the help of SimaPro software and by applying the environmental footprint (EF) 3.0 method. The economic analysis on the biorefinery’s economic viability, equipment, and production costs reveals a positive decision for bioethanol production from eucalyptus residues due to logistical and transportation costs. The minimum ethanol selling price (MESP) obtained was 2.19 €/L and 2.45 €/L for eucalyptus residues and corn stover, respectively. From the LCA with a functional unit of 1 MJ of ethanol, bioethanol production from eucalyptus residues results in a single score impact of 37.86 µPt, whereas for corn stover, it is 33.47 µPt. In the climate change impact category, the eucalyptus residues scenario has an impact of 0.264 kg CO2 eq/MJ ethanol while corn stover leads to 0.254 kg CO2 eq/MJ ethanol. In-situ enzyme production, heat integration, and the use of renewable energy sources were also analyzed. Combining in situ enzyme production with renewable energy sources lowers CO2 equivalent emissions by 89% for both feedstocks, in comparison to the base-case scenario.
- Parametric programming technique for global optimization of wastewater treatment systemsPublication . Teles, João P.; Castro, Pedro; Matos, Henrique A.This paper presents a parametric programming technique for the optimal design of industrial wastewater treatment networks (WTN) featuring multiple contaminants. Inspired in scientific notation and powers of ten, the proposed approach avoids the non-convex bilinear terms through a piecewise decomposition scheme that combines the generation of artificial flowrate variables with a multi-parameterization of the outlet concentration variables. The general non-linear problem (NLP) formulation is replaced by a mixed-integer linear programming (MILP) model that is able to generate near optimal solutions, fast. The performance of the new approach is compared to that of global optimization solver BARON through the solution a few test cases.
- Biorefineries : a new concept for biomass based industriesPublication . Cabrita, Isabel; Nunes, Clemente Pedro; Sousa, Gabriel; Matos, Henrique A.
- Short-Term scheduling of a polymer compounding plantPublication . Castro, Pedro; Barbosa-Póvoa, Ana Paula; Matos, Henrique A.This paper addresses the optimal short-term scheduling of a three parallel production line plymer compounding plant, whose equipments require cleaning between product changeovers. A very effective user-friendly software tool was developed, which consists of a general scheduling model coupled with capabilities of Microsoft Excel for data handling and analysis. The scheduling model is based on a Resource Task Network discrete time formulation and leads to Mixed Integer Linear Programming problems. As outputs the user can access the optimal schedules for a number of different objectives.
- Univariate parameterization for global optimization of mixed-integer polynomial problemsPublication . Teles, João P.; Castro, Pedro; Matos, Henrique A.This paper presents a new relaxation technique to globally optimize mixed-integer polynomial programming problems that arise in many engineering and management contexts. Using a bilinear term as the basic building block, the underlying idea involves the discretization of one of the variables up to a chosen accuracy level (Teles, J.P., Castro, P.M., Matos, H.A. (2013). Multiparametric disaggregation technique for global optimization of polynomial programming problems. J. Glob. Optim. 55, 227–251), by means of a radix-based numeric representation system, coupled with a residual variable to effectively make its domain continuous. Binary variables are added to the formulation to choose the appropriate digit for each position together with new sets of continuous variables and constraints leading to the transformation of the original mixed-integer non-linear problem into a larger one of the mixed-integer linear programming type. The new underestimation approach can be made as tight as desired and is shown capable of providing considerably better lower bounds than a widely used global optimization solver for a specific class of design problems involving bilinear terms.
- Multi-parametric disaggregation technique for global optimization of polynomial programming problemsPublication . Teles, João P.; Castro, Pedro; Matos, Henrique A.This paper discusses a power-based transformation technique that is especially useful when solving polynomial optimization problems, frequently occurring in science and engineering. The polynomial nonlinear problem is primarily transformed into a suitable reformulated problem containing new sets of discrete and continuous variables. By applying a term-wise disaggregation scheme combined with multi-parametric elements, an upper/lower bounding mixed-integer linear program can be derived for minimization/maximization problems. It can then be solved to global optimality through standard methods, with the original problem being approximated to a certain precision level, which can be as tight as desired. Furthermore, this technique can also be applied to signomial problems with rational exponents, after a few effortless algebraic transformations. Numerical examples taken from the literature are used to illustrate the effectiveness of the proposed approach.
- Performance indicators for reactive distillation designPublication . Filipe, Rui M.; Matos, Henrique A.; Novais, Augusto Q.A cost indicator for the design and multi-objective optimization of reactive distillation columns, designated capacity, was introduced in previous work by the authors. The question of this indicator’s effectiveness as a measure of the actual column cost, is herein investigated over a number of designs by comparing it with the value obtained by means of conventional costing procedures. The results show that the level of accuracy obtained when using capacity is satisfactory and certainly acceptable for a preliminary design stage.
- Analysis of processing systems involving reaction and distillation : the synthesis of ethyl acetatePublication . Filipe, Rui M.; Castro, Pedro; Matos, Henrique A.; Novais, Augusto Q.The integration of reaction and separation into a single process unit, i. e., reactive destillation, may offer several advantages over conventional systems that use a reactor followed by a distillation column. In this paper we explore the operational characteristics of reactive distillation and highlight some of this potential benefits, using the production of ethyl acetate as an illustrative example. With this aim, the two types of system are compared employing different reactor types and a number of performance indicators, such as yield, conversion, purity, specific energy consumption and residence time. A sensitivity analysis is carried out on some variables and parameters, in order to explore and define the distillation columns operating conditions. As expected, results point to a clear advantage of reactive distillation allowing for the azeotrope to be surpassed and for the overcoming of chemical equilibrium, favouring an increase in conversion and product purity, along with reduced operating costs.