Browsing by Subject "Techno-economic analysis"

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    Biomass to chemicals: process design and kinetic studies for the conversion of sugars into 5-hydroxymethylfurfural
    (2013-12) Torres Rippa, Ana Ines
    Biomass is an abundant resource that represents a promising, renewable, alternative for the production of fuels and chemicals. In this context, the concept of biorefinery has emerged as the future substitute of the petroleum refinery. Its economic viability will largely depend on integrating the production of biofuels with high-value chemicals. Hence, considerable research effort is devoted to the development of laboratory scale strategies to obtain chemicals from biomass. Systems-type analyses ranging from techno-economic studies to the development of kinetic models are required to evaluate the different process alternatives, and these are the focus of this thesis.In the first part, the production of 5-hydroxymethylfurfural (HMF), a sugar-derived furanic compound that acts as a precursor of building blocks for polymers, is addressed. Two flowsheets for the production of HMF from fructose were developed and evaluated. Rigorous material balances and kinetics, coupled with mathematical optimization were used to calculate the minimum price at which HMF has to be sold in order to balance raw materials (fructose), energy and capital costs. Sensitivity analysis was performed to evaluate the effect of relevant parameters. Based on these, advances that are required to reduce HMF production costs were identified and experimental research directions proposed.The second part of the thesis studies of the isomerization of glucose into fructose using tin containing zeolites (Sn-beta). This step, traditionally done with enzymes, is known to account for a substantial portion of fructose cost, thus alternative processes have the potential to reduce the production costs of sugar-derived molecules. Analysis of preliminary experimental data showed that the conventional kinetic model developed for the enzyme catalyzed reaction breaks down when the reaction is catalyzed by Sn-beta. Motivated by this, a plan that combines design of experiments, modeling and parameter estimation was proposed to elucidate the mechanism. It was found that the catalyst deactivates and that formation of by-products cannot be neglected. A phenomenological model that describes the isomerization reaction in the presence of deactivation was developed, and the corresponding kinetic parameters estimated from experimental data. The model thus obtained was used to assess the economics of glucose to HMF processes.
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    Process Modeling And Techno-Economic Analysis Of Zeolite Membrane Separation Processes
    (2018-04) Mittal, Nitish
    Zeolite membrane separation is considered to be a promising alternative to the traditional energy-intensive industrial separation techniques such as distillation. Currently, zeolite membranes are implemented in industry only for solvent dehydration applications. However, good separation performance is obtained at laboratory scale for various applications such as bioethanol enrichment, hydrogen recovery, natural gas purification, butane isomer separation, xylene isomer separation, etc. This progress should pave the way for the industrial implementation for other applications. Although significant progress has been made in preparation, characterization and commercialization of zeolite membranes, rigorous models, which can predict the membrane performance in industrial settings, are not available in the literature. Mathematical and process modeling plays an important role in the implementation and evaluation of any new technology or application. Thus, specific objectives of this thesis are to (i) design and develop a detailed mathematical model of a zeolite membrane separation process for accurate performance prediction under a wide variety of operating conditions, and (ii) develop and optimize a conceptual process design approach and perform a techno-economic evaluation for several significant application specific flowsheets. In this thesis, complex challenges both at the chemical engineering fundamentals and the process scale have been addressed. A detailed mathematical model of a zeolite membrane separation based on adsorption-diffusion phenomenon is formulated using Maxwell-Stefan equations. In addition to the adsorption and diffusion based transport through zeolite layer, factors such as mass transfer through the porous support, the use of a sweep gas, concentration polarization phenomenon and presence of defects are also discussed. The adsorption-diffusion model (including external resistances) is then integrated with the process-scale governing equations to assess the industrial potential of zeolite membranes. Further, conceptual process designs have been modeled and techno-economic evaluation has been performed to evaluate the scope of zeolite membrane separation for several applications in chemical and bio-based refineries, including butane isomer separation, bioethanol enrichment and propylene-propane separation. Both the stand-alone membrane systems and hybrid membrane-distillation systems have been considered. A hybrid membrane-distillation process is found to be energy efficient and economically attractive over stand-alone membrane systems. Finally, a net present value of the system is analyzed to generate a set of performance targets in term of the permeance and the membrane cost.