Nuno Dinis Couto

Nuno Dinis Couto
University of Porto | UP · Departamento de Engenharia Mecânica

Ph.D. in Mechanical Engineering

About

43
Publications
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848
Citations

Publications

Publications (43)
Article
The presented study focuses on a thermodynamic analysis conducted on steam gasification of Portuguese municipal solid wastes (MSW). Current literature addressing this issue is extremely scarce due to the complexity in handling MSW’s heterogeneity. To fill this significant gap, a mathematical model built upon a reliable set of experimental runs from...
Article
Waste management is becoming one of the main concerns of our time. Not only does it takes up one of the largest portions of municipal budgets but it also entails extensive land use and pollution to the environment using current treatment methods. Steam gasification of Portuguese municipal solid wastes was studied using a previously developed comput...
Article
Gasification has been identified as a promising method of municipal solid waste (MSW) conversion to energy due to its pollution minimization effects and high overall efficiency. Recent studies have been carried out to produce hydrogen through MSW gasification with promising results. Despite this, it is still necessary to develop mathematical models...
Article
One of the major setbacks regarding commercial size reactors is the scale-up phenomenon. Studies linking laboratory-scale to industrial-scale experiments are extremely scarce due to hard logistic and associated costs that are significant high. The use of numerical models can help to fill this gap thus minimizing the risk and uncertainty associated...
Conference Paper
A low cost methodology of chiller analysis and forecasting was developed to compete with Climacheck, currently the most used equipment on the market. This methodology comprises two types of analysis, internal and external. The internal method analyzes the several chiller elements and evaluates their behavior. The external analysis predicts the equi...
Conference Paper
A radiative cooling system applied to a typical Portuguese building was studied in order to minimize the electric consumption of a heat pump. The cooling system consists of an inertia tank which absorbs excess heat from the building, and dissipates it using a thermal photovoltaic panel. This is a 24h working system, during the day absorbs the exces...
Chapter
A two dimensional CFD model for MSW gasification has been used to predict and analyze the viability of the hydrogen generation from MSW gasification. The model is based in an Eulerian-Eulerian approach to describe the transport of mass, momentum and energy for the solid and gas phases. The model is applied to a fluidized bed gasifier to full predic...
Article
Full-text available
A volume-of-fluid (VOF) finite volume model under the ANSYS® Fluent framework was coupled with the response surface method (RSM) to find the best operating conditions within a jettability window for two selected responses in a drop-on-demand inkjet printing process. Twenty-five runs were generated using a face centred design and numerical simulatio...
Article
Urbanization, mainly caused by population growth and industrialization, is causing serious environmental problems. Municipal solid waste (MSW) is one of the major challenges facing the world today. In Portugal the growing volume of MSW has become a central problem for municipalities, due to lack of space and the high costs to solve it. Gasification...
Article
A 2-D multiphase CFD model was coupled with advanced statistical methods to find the best operating conditions to maximize a set of selected responses that characterize the normal operation of a pilot scale fluidized bed gasifier running Municipal Solid Waste. After using CFD simulations to compute 7 responses at 27 different operating conditions,...
Article
This work comprises the study of several mixtures of air with O2, CO2 and steam in a pilot scale gasification plant. Out of eight substrates characteristic of south-central and southern Portugal, Miscanthus was chosen for revealing the highest potential for energy generation and for its friendliness from an ecological standpoint. Experiments with M...
Chapter
Full-text available
Recent reports from top universities state that in spite of having great national importance, there are dozens of fields of study that are suffering due to a lack of funding. Perhaps the greatest tool available to assist researchers with this regard is numerical simulation. This tool allows cutting costs, decreasing the necessary design cycle and a...
Poster
Municipal solid waste (MSW), one of the main by-products of an urban lifestyle, is becoming one of the main concerns of our time. Caused by accelerated population growth, combined with high socio-economic development and rapid urbanization, its incorrect management poses an environmental risk to human health. Gasification has received a renewed int...
Conference Paper
Current methods of municipal solid waste (MSW) management contribute to greenhouse gas generation and its resulting damage to the environment. Gasification is starting to be seen as an attractive solution due to its environmental performance. However, to become the mainstream method of treatment it still requires overcoming some technical challeng...
Article
Full-text available
In modeling fluidized bed gasification experiments, equilibrium and CFD models are valuable options. The existence of multi-dimensional effects inside the reactor vessel due to the kinetics of the process and the fluid dynamics phenomena could result in deviation from the zero-dimensional assumption. Complex models integrating kinetics and hydrodyn...
Conference Paper
A two-dimensional CFD model was developed in order to predict the gasification of municipal solid waste (MSW). An Eulerian-Eulerian approach was used to describe the transport of mass, momentum and energy for both solid and gas phases. Numerical results were validating using data gathered from the literature. Influence of gasification temperature a...
Conference Paper
This paper presents a numerical 3D methodology applied to gasification of Portuguese coffee husk residues. The numerical simulation results were compared and validated versus a set of runs which were gasified in a bubbling fluidized semi-industrial unit. Results were also compared with 2D results obtained for the same set of experiments [1]. In thi...
Article
A 2-D numerical model based on the Computational Fluid Dynamic (CFD) framework was developed to investigate the influence of oxygen-enriched air on a biomass gasification process. Both gas and solid phases were described using and Eulerian–Eulerian approach exchanging mass, energy and momentum. The kinetic theory of granular flow was used to evalua...
Article
A comprehensive two-dimensional multiphase model was developed to describe the gasification of three large available Portuguese biomasses in a pilot scale fluidized bed gasifier within the computational fluid dynamics Fluent framework. An Eulerian−Eulerian approach was implemented to handle both the gas and the dispersed phases. The kinetic theory...
Conference Paper
The present study addresses SYNGAS combustion in static chamber, using both experimental and numerical approaches, in order to derive the quenching distance and heat flux in laminar syngas–air flames. Three typical mixtures of H2, CO, CH4, CO2 and N2 are considered as representative of the syngas coming from wood gasification, and its laminar combu...
Article
An exergy analysis was carried out considering the combustion of methane and syngas obtained from biomass pine residues, abundant specie in Portugal. Taking into account that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considered as resulting from different hypothetical paths each one characterize...
Article
This paper aims at presenting a numerical study considering the effect of oxygen concentration varied from 21% (v/v) to 40% (v/v) in enriched-air-pine biomass gasification. The gasification technology still to be in the early stage of development in Portugal and numerical studies to describe potential scenarios of biomass usage (a large amount of p...
Article
Full-text available
This paper aims at presenting a numerical study considering the effect of oxygen concentration varied from 21% (v/v) to 40% (v/v), moisture level and steam to biomass ratio on the production of H2 enriched syngas obtained by the gasification of biomass pine residues. H2 enriched syngas is particularly suitable to feed solide oxide fuel cells (SOFCs...
Conference Paper
Full-text available
Interest in the technology of gasification has shown a number of ups and downs since its first appearance. It appears that interest in gasification research correlates closely with the relative cost and availability of liquid and gaseous fossil fuels. Gasification is a versatile thermo-chemical conversion process which produces a gas mixture of H2,...
Conference Paper
Full-text available
A two-dimensional computational model was developed in order to describe the biomass gasification process in a fluidized bed reactor using coffee husks within the commercial CFD code FLUENT. Both, gas phase and solid phase, were described using and eulerian-eulerian approach exchanging mass, energy and momentum. Results from the numerical model wer...
Conference Paper
Full-text available
Hazardous waste is the most difficult waste to be managed, since in the treatment process, heavy metal and dioxin among others are obtained. The outcome elements are dangerous not only for the environment but also for public health. In Portugal, in the last two decades, the waste management has been a major concern. Many political changes were made...
Article
Full-text available
An exergy analysis was carried out considering the combustion of methane and syngas obtained from biomass pine residues, abundant specie in Portugal. Taking into account that the irreversibilities of a thermodynamic process are path dependent, the combustion process was considered as resulting from different hypothetical paths each one characterize...
Article
Full-text available
With the workmanship decrease in farms, the necessity to rationalize the use of other inputs and the development of technology has rapidly expanded the use of computer simulation in agricultural systems. One of the agricultural systems in which the modeling process of plant growth has been more engaged is the greenhouse production for horticultural...
Article
Full-text available
The main goal of this paper is to analyze the exergy losses during the shock and rarefaction wave of hydrogen-air mixture. First, detonation parameters (pressure, temperature, density, and species mass fraction) are calculated for three cases where the hydrogen mass fraction in air is 1.5%, 2.5%, and 5%. Then, exergy efficiency is used as objective...
Article
Full-text available
Two-dimensional, steady, incompressible Navier-Stokes and energy equations are expressed in the stream function/vorticity formulation and solved numerically by finite difference method to study effects of buoyancy on fluid flow and heat transfer from a horizontal circular cylinder. The cylinder is exposed to approaching flow stream, for parallel (p...
Conference Paper
The momentum and energy equations describing the steady cross-flow of power-law fluids past a rotating heated cylinder have been solved numerically. The results highlight the influence of dimensionless rotational velocity (0
Conference Paper
As equações do movimento, da energia e da continuidade para o escoamento estacionário de fluidos descritos pela lei de potência em torno de um cilindro isotérmico em rotação são resolvidas numericamente. O estudo centra-se na investigação da tranferência de calor a partir de um cilindro em rotação para os números de Reynolds (Re =5 e 40), números d...

Projects

Projects (2)
Project
Through a massive population growth, waste management has become one of the main concerns of our time. In Portugal the growing volume of municipal solid waste has become a central problem for municipalities, due to lack of space and the high costs to solve it. Gasification has received a renewed interest in the municipal solid waste treatment since it limits dioxins formation, presents higher efficiency and requires less expensive gas cleaning equipment when compared to available methods gas. However, to make to process more appealing to both private sector and government institutions is necessary to overcome some concerns related to the process. To expedite the mainstream of this technology a first and second law analysis conducted on Portuguese municipal solid waste was carried out.