Influence of Energy Input on Behaviour of Multiphase Processes

Heat Transfer Engineering, 2011

Research Interests: For years, industrial and manufacturing processes have relied on scaling-up to reduce production costs and increase competitiveness. Advances in Process Intensification, which aims to substantially reduce capital cost, energy consumption, environmental footprint, while increasing safety and production output, have the potential to change the industrial and manufacturing landscape in the upcoming years. My research aims to systematically search for intensification opportunities – enhancement of intrinsic effects, combination of synergetic processes, novel equipment designs, among others – by using rigorous mathematical approaches, fundamental laws, modeling, and computational simulation to explore a wide range of scales (multiscale-integrated) in which process intensification opportunities can be sought, from molecular, to equipment, to the systems level. During my Ph.D. I have developed research projects that involved rigorous mathematical modeling and simulation of reaction-diffusion processes in porous media in a multiscale fashion. In addition, I have developed models to systematically intensify reactive separation processes that guarantee global optimality. The set of skills I have learned includes the development of mathematical models from fundamental principles – mass, momentum, and energy balances; reaction kinetics, thermodynamic principles, and advanced transport models such as Stefan-Maxwell and Dusty-Gas Model – for multiscale, multiphase physical systems. In addition, I had formal training in optimization of large-scale process networks and process synthesis, which gives me the ability to find innovative conceptual designs. This combined with my previous industry experience as a senior mechanical engineer in designing and implementing large-scale industrial projects, in which I performed several activities from proposal writing to conceptual design. I am sure that my background and experience qualifies me to develop a strong research program in intensified chemical/manufacturing processes and novel equipment designs. Proposal experience: NSF-EAGER, EERE-Industrial Assessment Centers, CEC L.A. Regional Energy Innovation Cluster. Awards: UCLA Graduate Division Doctoral Dissertation Year Fellowship; UCLA JP Lemann Fellowship. Ph.D. Dissertation: “Multiscale performance limits quantification of chemical processes networks” Supervised by Prof. Vasilios I. Manousiouthakis, University of California, Los Angeles. Teaching Interests: I have over three years of experience as a teaching fellow for chemical engineering courses in both classroom and laboratory settings. I am prepared to teach general undergraduate and advanced graduate level courses in Chemical Engineering and Mechanical Engineering, such as transport phenomena, thermodynamics, heat transfer, fluid mechanics, controls, separations, numerical and mathematical methods, and process design. My previous experience as a senior engineer at a project design company can be beneficial to students of all levels, enriching the learning processes of cross-disciplinary classes such as process economics, process design, and entrepreneurship. I am also excited to teach graduate courses in optimization and process design, and look forward to developing new courses related to energy systems and process intensification. Future direction: As a faculty, I would like to apply my research efforts on the development of novel processes, equipment design, and production schemes that will help to shape an intensified, safer, greener, data-driven process industry. Through a combination of rigorous modeling, multiscale computational simulation, and optimization/control techniques, a diverse range of both traditional and new processes/manufacturing systems (reactive distillation, membrane reactors, additive manufacturing, among others) can be analyzed, modified, and/or synthesized in order to maximize performance. I envision myself collaborating closely with smart manufacturing/process intensification research centers, as well as companies in the manufacturing and processing industries. Additional details are available at www.flaviodacruz.com Publications: da Cruz, F. E., and Manousiouthakis, V.I. "Process intensification of reactive separator networks through the IDEAS conceptual framework." Computers & Chemical Engineering (2016). da Cruz, F. E., and Manousiouthakis V.I. "Parametric studies of steam methane reforming using a multiscale reactor model." Ind. and Eng. Chemistry Research (Submitted). Karagöz, S., da Cruz, F. E., Tsotsis, T. T., and Manousiouthakis, V.I. " The multiscale (pellet-reactor scale) membrane reactor (MR) modeling and simulation: Molecular sieve MR for hydrogen production by low-temperature water gas shift reaction." Ind. and Eng. Chemistry Research (Submitted). da Cruz, F. E., and Silvio de Oliveira Junior. "Petroleum refinery hydrogen production unit: exergy and production cost evaluation." International Journal of Thermodynamics 11, no. 4 (2008): 187-193.

Mathematical Problems in Engineering, 2021

2005

The project "Multiphase flows in process industry (ProMoni)" 1.1.2001– 30.4.2004 was a research consortium carried out jointly by seven research groups from VTT, University of Jyväskylä, Tampere University of Technology, Åbo Akademi University and University of Kuopio. It included modeling, development and validation of numerical methods as well as development of new experimental techniques for multiphase flows found in process industry. The primary fields of application are in fluidized beds and in various processes found in the paper and pulp industry. This extensive final report of the ProMoni project includes results from experimental and numerical research of bubbling fluidized beds indicating that modelling produces the bed behaviour realistically and the simulations can be used in developing approximative macroscopic two-phase models. A new gas-solid drag correlation model was successfully used within Fluent CFD code to simulate the typical flow structures in a circ...

International Journal of Engineering Science, 2006

A general thermodynamic theory for chemically active multiphase solid-fluid mixtures in turbulent state of motion is formulated. The global equations of balance for each phase are ensemble averaged and the local conservation laws for the mean motions are derived. As a classical treatment, the averaged form of the Clausius-Duhem inequality is used and the thermodynamics of the chemically active mixtures in turbulent state of motion is studied. Particular attention is given to the species concentration of the miscible fluid constituents and chemical reaction effects, in addition to the transport of the phasic fluctuation energies between phases. Based on the averaged entropy inequality, constitutive equations for the stresses, energy, heat and mass fluxes of various species are developed. Explicit governing equations of motion, along with the equation of the dissipation rate of the turbulent kinetic energy are also derived and discussed. A particular emphasis is on the thermodynamically consistent formulation of different solid-fluid interaction terms in these equations.

International Journal of Multiphase Flow, 2010

Multiphase flows have received increasing attention over the past decades. This paper describes the research carried out in Thermo-Energy Engineering Institute of Southeast University in recent years, focusing on several common issues associated with multiphase flows in industry, such as: boiling of falling film and complex structure of gas-liquid flow under large difference in temperature, free surface flows involving liquid jets and drop formation, mixing behaviors of gas-liquid-solid three-phase flow, and fluidization characteristics of cylindrical particles. Numerical methods ranging from empirical to CFD models were developed for predictions, and experimental works were essentially conducted for validation and modification. For all cases, simulated results were validated with experiments and good agreements were obtained. Based on the combined modeling and experimental approach, fundamental understanding of multiphase processes in a specific circumstance is achieved under conditions relevant to the actual industrial-scale, such as transport phenomena, flow patterns, fluid dynamics and interactions between phases.

Chemical Engineering Science, 2004

In this paper a multi-scale simulation method for modelling dispersions in a novel multiphase reactor is presented. This novel reactor is a continuous reactor which consists of repeated identical small mixing elements. The reactor is excellent for studying the effect of turbulence on drop size distributions since turbulence is continuously produced and dissipated along the reactor. Furthermore the energy dissipation within each element is very homogeneous. In addition it allows optical access at all positions along the reactor.

intechopen.com

Chemical Engineering Science, 1999

Multiphase reactors are found in diverse applications such as in manufacture of petroleum-based fuels and products, in production of commodity and specialty chemicals, pharmaceuticals, herbicides and pesticides, in re"ning of ores, in production of polymers and other materials, and in pollution abatement. In all such applications, the knowledge of #uid dynamic and transport parameters is necessary for development of appropriate reactor models and scale-up rules. The state of the art of our understanding of the phenomena occurring in three-phase reactors such as packed beds with two-phase #ow, slurry bubble columns and ebullated beds is summarized in this review.

The flow problems considered in previous chapters are concerned with homogeneous fluids, either single phases or suspensions of fine particles whose settling velocities are sufficiently low for the solids to be completely suspended in the fluid. Consideration is now given to the far more complex problem of the flow of multiphase systems in which the composition of the mixture may vary over the cross-section of the pipe or channel; furthermore, the components may be moving at different velocities to give rise to the phenomenon of "slip" between the phases. Multiphase flow is important in many areas of chemical and process engineering and the behaviour of the material will depend on the properties of the components, the flowrates and the geometry of the system. In general, the complexity of the flow is so great that design methods depend very much on an analysis of the behaviour of such systems in practice and, only to a limited extent, on theoretical predictions. Some of the more important systems to be considered are: Mixtures of liquids with gas or vapour. Liquids mixed with solid particles ("hydraulic transport"). Gases carrying solid particles wholly or partly in suspension ("pneumatic transport"). Multiphase systems containing solids, liquids and gases. Mixed materials may be transported horizontally, vertically, or at an inclination to the horizontal in pipes and, in the case of liquid-solid mixtures, in open channels. Although there is some degree of common behaviour between the various systems, the range of physical properties is so great that each different type of system must be considered separately. Liquids may have densities up to three orders of magnitude greater than gases but they do not exhibit any significant compressibility. Liquids themselves can range from simple Newtonian liquids such as water, to non-Newtonian fluids with very high apparent viscosities. These very large variations in density and viscosity are responsible for the large differences in behaviour of solid-gas and solid-liquid mixtures which must, in practice, be considered separately. For, all multiphase flow systems, however, it is important to understand the nature of the interactions between the phases and how these influence the flow patterns — the ways in which the phases are distributed over the cross-section of the pipe or duct. In design it is necessary to be able to predict pressure drop which, usually, depends not only on the flow pattern, but also on the relative velocity of the phases; this slip velocity will influence the holdup , the fraction of the pipe volume which is occupied by a particular phase. It is important to note that, in the flow of a