Computer-Aided Sustainable Process Synthesis-Design and Analysis

Processyntese involverer undersøgelse af kemiske reaktioner, der er nødvendige for at producere det ønskede produkt, udvælgelse af separationsteknikker nødvendige for downstream forarbejdning, samt beslutninger om sekvensering af de involverede separationsprocesser. For en effektiv og fleksibel designtilgang, er der behov for en systematisk måde at identificere de typer af opgaver og operationer, der skal udføres, den tilsvarende design af operation-udstyr, deres konfiguration, masse-energistrømme m.v., hvilket giver et optimalt processkema. På grund af det faktum, at processynteseproblemer er af natur kombinatoriske og med flere mulige løsninger, er der blevet foreslået en forskellige metoder til at overkomme dette. Men løsningen til ethvert syntese-design problem er afhængig af søgningsområdet af alternativer og kriterierne for procesydeevne, som i de fleste tilfælde er påvirket af økonomiske faktorer. Dette arbejde fokuserer på udvikling og anvendelse af et computerstøttet platform for bæredygtig syntese-design og analyse af processkemaer ved at generere mulige alternativer, der dækker hele søgningsområdet og omfatter analyseværktøjer for bæredygtighed, LCA og økonomi. Syntesemetoden er baseret på en gruppebidragsbaseret hybridmetode, hvor kemisk processkemaer syntetiseres på samme måde som atomer eller grupper af atomer syntetiseres til dannelse af molekyler i computerstøttet molekylært design (eng: CAMD) teknikker. Byggestenene i et processkemasyntese problem er betegnet som procesgrupper, som repræsenterer en enkelt eller et sæt af enhedsoperationer, der er udvalgt på metoder baseret på termodynamiske grundlag. Disse byggesten kombineres derefter under anvendelse af regler for tilslutningsmuligheder for at generere alle de mulige processkemaalternativer. Den største fordel ved at repræsentere processkemaer med procesgrupper er, at udførelsen af hele processen kan vurderes fra bidragene fra de enkelte procestrinsgrupper mod processkemaegenskaberne (f.eks forbrugt energi). De udviklede processkemaegenskabsmodeller omfatter energiforbrug, carbon footprint, produktudvinding, produktrenhed osv. På denne måde er hele listen over mulige kemiske processkemaer hurtigt genereret, screenet og udvalgt til yderligere analyse. I det næste trin, er udformningen af de mest lovende processkemakandidater udført gennem en omvendt simulationsmetode, hvor designparametre for enhedsoperationer i processkemaet er beregnet ud fra udvalgte definitioner af procesgrupper. I næste fase analyseres det valgte design, til at identificere begrænsninger eller flaskehalse (hot-spots) ved hjælp af en omfattende analysemetode bestående af økonomiske, livscyklus og bæredygtigheds faktorer, der omsættes til procesdesignmål. I den afsluttende fase identificeres hot-spotsne, som er målrettet til den samlede procesforbedring og til at skabe innovative designs. I dette arbejde er den udviklede platform testet sammen med de tilhørende metoder og værktøjer gennem tre casestudier med relation til både kemiske og biokemiske industri med henblik på at fastslå anvendelsesmulighederne af platformen. I hvert af tilfældene er de mange alternativer og litteraturdesignene hurtigt genereret og evalueret. I alle de testede casestudier var de endelige designs, der genereres af platformen, nye og mere bæredygtige.Process synthesis involves the investigation of chemical reactions needed to produce the desired product, selection of the separation techniques needed for downstream processing, as well as taking decisions on sequencing the involved separation operations. For an effective, efficient and flexible design approach, what is needed is a systematic way to identify the types of tasks-operations that need to be performed, the corresponding design of the operation-equipment, their configuration, mass-energy flows, etc., giving an optimal flowsheet. Due to the fact that process synthesis problems are by nature combinatorial and open ended, a number of different solution approaches have been proposed. However the solution for any synthesis-design problem is dependent on the search space of alternatives and the process performance criteria which in most cases are influenced by economic factors. This work focuses on the development and application of a computer-aided framework for sustainable synthesis-design and analysis of process flowsheets by generating feasible alternatives covering the entire search space and includes analysis tools for sustainability, LCA and economics. The synthesis method is based on group contribution and a hybrid approach, where chemical process flowsheets are synthesized in the same way as atoms or groups of atoms are synthesized to form molecules in computer aided molecular design (CAMD) techniques. The building blocks in flowsheet synthesis problem are called as process-groups, which represent a single or set of unit operations that are selected by employing a thermodynamic insights based method. These building blocks are then combined using connectivity rules to generate all the feasible flowsheet alternatives. The main advantage of representing the flowsheet with process-groups is that, the performance of the entire process can be evaluated from the contributions of the individual process-groups towards the selected flowsheet property (for example, energy consumed). The developed flowsheet property models include energy consumption, carbon footprint, product recovery, product purity etc. In this way, the entire list of feasible chemical process flowsheets are quickly generated, screened and selected for further analysis. In the next stage, the design of the most promising process flowsheet candidates is performed through a reverse simulation approach, where the design parameters of the unit operations in the process flowsheet are calculated from selected process-groups definition. In the next stage the selected design is analyzed, for identifying process limitations or bottlenecks (hot-spots) using a comprehensive analysis method consisting of economic, life cycle and sustainability factors that are translated into design targets. In the final stage the identified hot-spots are targeted for overall process improvement and to generate innovative designs. In this work the developed framework along with the associated methods and tools is tested through three case studies related to both chemical and biochemical industry in order to ascertain the applicability of the framework. In each of the cases numerous alternatives of novel and designs reported by others are quickly generated and evaluated. In all the case studies tested, the final design generated by the framework was novel and more sustainable

Functional monolithic platforms for antibody purification

Dissertação para obtenção do Grau de Doutor em Química SustentávelFundação para a Ciência e Tecnologia - contracts PEst-C/EQB/LA0006/2011, MIT-Pt/BS-CTRM/0051/2008, PTDC/EBB-BIO/102163/2008, PTDC/EBBBIO/ 098961/2008, PTDC/EBB-BIO/118317/2010 and doctoral grant SFRH/ BD/62475/2009, and Fundação Calouste Gulbenkia

Isobutane Alkylation Process Synthesis by means of Hybrid Simulation-Multiobjective Optimization

Multiobjective Generalized Disjunctive Programming (MO-GDP) optimization has been used for the synthesis of an important industrial process, isobutane alkylation. The two objective functions to be simultaneously optimized are the environmental impact, determined by means of LCA (Life Cycle Assessment), and the economic potential of the process. The main reason for including the minimization of the environmental impact in the optimization process is the widespread environmental concern by the general public. For the resolution of the problem we employed a hybrid simulation- optimization methodology, i.e., the superstructure of the process was developed directly in a chemical process simulator connected to a state of the art optimizer. The model was formulated as a GDP and solved using a logic algorithm that avoids the reformulation as MINLP -Mixed Integer Non Linear Programming-. Our research gave us Pareto curves compounded by three different configurations where the LCA has been assessed by two different parameters: global warming potential and ecoindicator-99.We acknowledge the support from the Spanish Ministry of Science and Innovation (CTQ2012-37039-C02-02)

Hybrid data-driven and mechanistic modeling approaches for multiscale material and process design

The world’s increasing population requires the process industry to produce food, fuels, chemicals, and consumer products in a more efficient and sustainable way. Functional process materials lie at the heart of this challenge. Traditionally, new advanced materials are found empirically or through trial-and-error approaches. As theoretical methods and associated tools are being continuously improved and computer power has reached a high level, it is now efficient and popular to use computational methods to guide material selection and design. Due to the strong interaction between material selection and the operation of the process in which the material is used, it is essential to perform material and process design simultaneously. Despite this significant connection, the solution of the integrated material and process design problem is not easy because multiple models at different scales are usually required. Hybrid modeling provides a promising option to tackle such complex design problems. In hybrid modeling, the material properties, which are computationally expensive to obtain, are described by data-driven models, while the well-known process-related principles are represented by mechanistic models. This article highlights the significance of hybrid modeling in multiscale material and process design. The generic design methodology is first introduced. Six important application areas are then selected: four from the chemical engineering field and two from the energy systems engineering domain. For each selected area, state-of-the-art work using hybrid modeling for multiscale material and process design is discussed. Concluding remarks are provided at the end, and current limitations and future opportunities are pointed out

Electrochemical Conversion of Biologically Produced Muconic Acid: Key Considerations for Scale-Up and Corresponding Technoeconomic Analysis

Muconic acid, an unsaturated diacid that can be produced from cellulosic sugars and lignin monomers by fermentation, emerges as a promising intermediate for the sustainable manufacture of commodity polyamides and polyesters including Nylon-6,6 and polyethylene terephthalate (PET). Current conversion schemes consist in the biological production of cis,cis-muconic acid using metabolically engineered yeasts and bacteria, and the subsequent diversification to adipic acid, terephthalic acid, and their derivatives using chemical catalysts. In some instances, conventional precious metal catalysts can be advantageously replaced by base metal electrocatalysts. Here, we show the economic relevance of utilizing a hybrid biological−electrochemical conversion scheme to convert glucose to trans-3-hexenedioic acid (t3HDA), a monomer used for the synthesis of bioadvantaged Nylon-6,6. Potential roadblocks to biological and electrochemical integration in a single reactor, including electrocatalyst deactivation due to biogenic impurities and low faradaic efficiency inherent to side reactions in complex media, have been studied and addressed. In this study, t3HDA was produced with 94% yield and 100% faradaic efficiency. With consideration of the high t3HDA yield and faradaic efficiency, a technoeconomic analysis was developed on the basis of the current yield and titer achieved for muconic acid, the figures of merit defined for industrial electrochemical processes, and the separation of the desired product from the medium. On the basis of this analysis, t3HDA could be produced for approximately $2.00 kg−1. The low cost for t3HDA is a primary factor of the electrochemical route being able to cascade biological catalysis and electrocatalysis in one pot without separation of the muconic acid intermediate from the fermentation broth

Replacement of the Legacy High-Cost Universal Support Fund with a Connect America Fund. Key Economic and Legal Considerations

On April 21, 2010, the Federal Communications Commission (FCC) released a Notice of Inquiry (NOI) and a Notice of Proposed Rulemaking (NPRM) that seek the public’s input on the FCC’s effort to replace the legacy high-cost universal service fund (USF) with a broadband “Connect America” fund (CAF). In effect, the FCC seeks to implement cost-cutting measures for existing voice support (USF) and create a new fund (CAF) to support the provision of broadband communications in areas that would be unserved without such support or that depend on USF support for the maintenance of existing broadband service. An initial review of the NOI/NPRM raises a number of key economic and legal considerations. In the following, we identify some of the considerations, questions, and challenges raised by the FCC’s USF reform attempt, which is likely to have far-reaching consequences not only for operators that currently rely on USF subsidies or broadband providers in high-cost regions but for the entire communications industry.The purpose of this note is not to provide an all-inclusive list of, or responses to, the critical questions raised by the NOI/NPRM, but rather to illustrate the complexities of this proceeding and the impact the proposed reforms may have on industry performance. As the CAF is necessary for the success of the FCC’s National Broadband Plan (NBP), the policy directions taken by the FCC in establishing it are critically important. USF reform is also essential to the performance and competitiveness of the U.S. communications industry and policy missteps could have serious economic and legal consequences.Federal Communications Commission, America Fund

Recent advances and future perspectives on more sustainable and energy efficient distillation processes

Distillation has held a very strong position in the chemical process industries for well over a century, and has, as a separation method, been around for millennia. The process can be designed directly without the need for experimentation unlike other novel separation processes, and distillation is a standard part of any undergraduate curriculum. So why the ongoing interest in this separation dinosaur? Due to distillation’s significant importance in industry, and its associated high energy requirements and thereby contribution to global warming, considerable effort is still needed to make the process more energy efficient, as well as to consider other heating sources beyond traditional fossil fuels. In this work, we will outline the most significant methods currently considered for energy efficiency of distillation, and provide an overview of where we may be heading as a discipline in our quest for a more sustainable chemical engineering future. We will argue that significant improvements have already been made, but more is still required by both industry and legislators. We need to consider a future without the use of fossil fuel-based feedstock or energy sources and switch towards renewable sources, and our future graduates need to be adequately prepared for such a future