Environmental Engineering Commons^™

Termodynamika Procesowa (Dla Me Aparatura Procesowa) Ćw., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

The Analysis Of Heat Transfer In A Gas-Gas Heat Exchanger Operated Under A Heat-Recirculating Mode, Mariusz Salaniec, Wojciech M. Budzianowski

Wojciech Budzianowski

The present paper presents the analysis of heat transfer in a gas-gas heat exchanger operated in a heat-recirculating mode.

An Overview Of Technologies For Upgrading Of Biogas To Biomethane, Wojciech M. Budzianowski

Wojciech Budzianowski

The present contribution presents an overview of technologies available for upgrading of biogas to biomethane. Technologies under study include pressure swing adsorption (PSA), high-pressure water wash (HPWW), reactive absorption (RA), physical absorption (PA), membrane separation (MS) and cryogenic separation (CS).

Influence Of Energy Policy On The Rate Of Implementation Of Biogas Power Plants In Germany During The 2001-2010 Decade, Izabela Chasiak, Wojciech M. Budzianowski

Wojciech Budzianowski

The current article describes energy policy tools, which caused intensive development of biogas-based power generation in Germany during the 2001-2010 decade. The German system of financial support to biogas power plants is presented in details. It is shown that in Germany, i.e. in a country characterised by similar climate and potentials to renewable energy to Poland, biogas power plants cover 10,7% of electricity demands in 2010, while all renewable energy sources cover only 5,4% of electricity demands. It is emphasised that under favourable Polish energy policy, the development of biogas energy can be very rapid.

Energetyka Niskoemisyjna, Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Bacterial Chemotaxis In Porous Media: Theory Derivation And Comparison With Experiments, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood

Francisco J. Valdes-Parada

Chemotaxis is the movement of organisms toward or away from the concentration gradient of a chemical species. Microbial chemotaxis has been shown to significantly increase contaminant degradation in subsurface environments with respect to traditional methods such as pump-and-treat. This type of transport phenomena often involves diffusion and convection along several scales. In this work we use the method of volume averaging to upscale the governing equations for in situ bioremediation by bacterial chemotaxis. The results are effective medium mass balance equations for both the bacteria and the chemical attractant. These equations are expressed in terms of average transport coefficients, which …

Interpretation Of Closure Variables In Upscaling, Francisco J. Valdes-Parada, Mark L. Porter, Brian D. Wood

Francisco J. Valdes-Parada

In many engineering applications, it is common to nd systems that involve transport at several scales. Despite the increasing computational capabilities, it is still not feasible to model a complete macroscopic system by direct numerical simulations at the microscale. Actually, it is more convenient to derive models at an intermediate level of scale between the microscale and the macroscale; this is the average scale. The derivation of models at this scale can be carried out by means of the method of volume averaging. The results from this method are averaged transport equations expressed in terms of eective medium coecients that …

One-Domain Approach For Heat Transfer At The Fluid-Porous Medium Inter-Region, Francisco J. Valdes-Parada, Carlos G. Aguilar-Madera, Benoît Goyeau, J. Alberto Ochoa-Tapia

Francisco J. Valdes-Parada

The modeling of transport phenomena in the zone of rapid changes between a fluid and a porous medium (i.e., the interregion) can be carried out using two distinctive approaches. The first one, generally called the one-domain approach, describes transport phenomena in the whole fluid-porous system using averaged macroscopic conservation equations including spatially dependent effective properties. These coefficients reduce to their respective constant values in the homogeneous fluid and porous regions of the system. As an alternative, the two-domain approach uses the transport equations with constant coefficients in the entire domain of each region, including the zone of drastic changes. To …

Derivation Of Complete Jump Boundary Conditions Between Homogeneous Media, Francisco J. Valdes-Parada, Benoît Goyeau, J. Alberto Ochoa-Tapia

Francisco J. Valdes-Parada

The modeling of transport phenomena between homogeneous regions requires the derivation of jump boundary conditions. These conditions account for the rapid spatial variations of the transport properties taking place near the dividing surface of the media. There has been a long debate in the literature about whether the discontinuity should apply to the fields (e.g., velocity, temperature, concentration) or to their fluxes. In this work, a general methodology giving rise to jump conditions for both the fields and the fluxes is proposed. This method, besides using a microscopic closure, introduces macroscopic deviation fields that lead to closure schemes for both …

Modelo Aproximado Del Coeficiente De Dispersión En Medios Porosos, Francisco J. Valdes-Parada, Helen D, Lugo-Méndez, J. Alberto Ochoa-Tapia

Francisco J. Valdes-Parada

En este trabajo, se utiliza el método del promedio volumétrico para la predicción del coeficiente efectivo de dispersión y la teoría de las funciones de Green para encontrar una solución analítica aproximada. Como simplificación de la celda representativa del medio poroso homogéneo, se usó la celda de Chang, imponiendo la condición de flujo reptante. Para corroborar los resultados se determinó numéricamente el coeficiente efectivo, en celdas unitarias periódicas usando el programa comercial basado en el método de de elemento finito COMSOL Multiphysics. El coeficiente efectivo de dispersión analítico obtenido en este trabajo presenta una tendencia análoga al numérico, además de …

Diseño De Una Parrilla Para La Reducción De Pérdidas De Energía En Estufas Convencionales, Francisco J. Valdes-Parada, Victor Castillo-Jimenez, Alberto Gabino-Zamora, Armando Astudillo-Velázquez

Francisco J. Valdes-Parada

Las estufas de gas convencionales tienen, por lo general, pérdidas considerables de energía alrededor del quemador, lo que disminuye su eficiencia e incrementa el consumo de recursos. Para atender este problema, en este trabajo se propone concentrar la mayor parte del calor hacia una sola región, para poder obtener la mayor cantidad de energía sin tener que suministrar más combustible y de esta manera aumentar la eficiencia de estufas convencionales. Para ello, se construyó un prototipo experimental a partir de cálculos de diseño teóricos. Con el prototipo ahorrador de energía se consiguió un ahorro hasta del 40% del consumo de …

Análisis De La Transferencia De Calor En Azoteas Verdes, Francisco J. Valdes-Parada, Verónica Freyre-Fonseca

Francisco J. Valdes-Parada

El problema de las islas urbanas de calor contribuye a los drásticos cambios climáticos que se sufren en ciudades densamente pobladas. Para atender este problema se tienen diversas alternativas, entre las cuales se contempla incorporar zonas verdes (e.g., paredes y azoteas verdes) en edificaciones que contrarresten los efectos de calentamiento excesivo. En este trabajo se estudia la transferencia de calor en edificaciones típicas de la ciudad de México utilizando diferentes configuraciones de zonas verdes. Los resultados muestran que el utilizar azoteas verdes tiene un efecto estabilizador en los perfiles locales de temperatura; sin embargo a nivel de toda una edificación, …

Modelado De Un Reactor Solar Para El Cracking De Metano, Francisco J. Valdes-Parada, Hernando Romero-Paredes

Francisco J. Valdes-Parada

En este trabajo se realiza el modelado de un reactor solar tubular con una capacidad de hasta 15 kW para la disociación térmica del metano. El reactor está compuesto por un tubo de grafito inmerso en una cavidad también de grafito que juega el papel de receptor del flujo solar concentrado. El objetivo de este trabajo es evaluar los perfiles de velocidad, de concentración y temperatura a lo largo del reactor en función de la concentración y el flujo de gas a la entrada del reactor. Con lo cual ha sido posible evidenciar algunos fenómenos poco discutidos durante la experimentación. …

Sobre La Suposición De Estado Cuasiestacionario En El Transporte De Calor De Una Ventana Doble, Francisco J. Valdes-Parada, Erika K. Flores-Romero, Geovanni Hernandez-Luna, Erick A. Aguilera-Romero

Francisco J. Valdes-Parada

Es sabido que la mayoría de las edificaciones modernas transfieren la mayor parte de la energía acumulada a través de ventanas. Por ello, en la medida en que se tengan modelos confiables para el transporte de calor a través de estos sistemas, se contará con mejores diseños que tienen una relación directa con el confort, ambiente y gasto energético de edificaciones. El modelado de la transferencia de calor en ventanas dobles suele llevarse a cabo considerando únicamente sus cristales y el aire atrapado entre ellos. Sin embargo, la temperatura del interior es, a su vez, una función del tiempo y …

Escalamiento De Dispersión De Contaminantes En La Ciudad De México, Francisco J. Valdes-Parada, J. Ruben Varela-Ham

Francisco J. Valdes-Parada

En días hábiles, la actividad vehicular más intensa en calles y avenidas de la ciudad de México se inicia a las 6:00 hs y se prolonga por aproximadamente 3 ó 4 horas. En ese periodo, la capa de mezclado permanece relativamente quieta y expuesta a recibir una carga importante de contaminantes producto de emisiones vehiculares. En esas condiciones de ausencia de movimientos atmosféricos verticales y horizontales, y de intensa actividad contaminante, adquieren importancia los procesos de dispersión que ocurren en la horizontal y a nivel del suelo.

En este trabajo se lleva a cabo un proceso de promediado de las …

Integral Formulation For The Solution Of Closure Problems In Upscaling Processes, Francisco J. Valdes-Parada

Francisco J. Valdes-Parada

The derivation of transport models at macroscopic scales can be carried out using upscaling techniques such as the method of volume averaging. This upscaling technique consists on averaging the transport equations that describe phenomena at the microscale. The result is the so-called eective medium models, which are expressed in terms of eective coecients that can be computed from the solution of the corresponding closure problems. In this work, we present an integral formulation based on Green's functions to carry out the formal solution of closure problems. This methodology not only provides a physical interpretation of the closure variables, but it …

Conference Proceedings 3rd International Scientific Conference On “Energy Systems With It” At Alvsjö Fair In Association With Energitinget March 16-17 2010, Dr. Erik Dahlquist, Dr. Jenny Palm

Dr. Erik Dahlquist

2010 “The Energiting” is performed for the 12th time. The International Scientific conference is arranged for the 3rd time. The organisers are Swedish Energy Agency, Mälardalen University and the Research School for Energy Systems with LiU, KTH, UU and CTH. The first topic will be “Energy systems” covering use of renewable energy sources, energy conversion and process efficiency improvement with new technologies, as well as societal aspects of the introduction of new technologies. The second topic is “Energy and IT”. This covers energy and load management, interaction between production, distribution and “consumption”, usage of data for decision support and control, …

Performance Evaluation Of Organic Emulsion Liquid Membrane On Phenol Removal, Yee Sern Ng, Jayakumar Natesan Subramaniam, Mohd Ali Hashim

Ng Yee-Sern

The percentage removal of phenol from aqueous solution by emulsion liquid membrane and emulsion leakage was investigated experimentally for various parameters such as membrane:internal phase ratio, membrane:external phase ratio, emulsification speed, emulsification time, carrier concentration, surfactant concentration and internal agent concentration. These parameters strongly influence the percentage removal of phenol and emulsion leakage. Under optimum membrane properties, the percentage removal of phenol was as high as 98.33%, with emulsion leakage of 1.25%. It was also found that the necessity of carrier for enhancing phenol removal was strongly dependent on the internal agent concentration.

Advances On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes

João F Gomes

This paper describes experimental work done towards the search for more profitable and sustainable alternatives regarding biodiesel production, using heterogeneous catalysts instead of the conventional homogenous alkaline catalysts, such as NaOH, KOH or sodium methoxide, for the methanolysis reaction. This experimental work is a first stage on the development and optimization of new solid catalysts, able to produce biodiesel from vegetable oils. The heterogeneous catalytic process has many differences from the currently used in industry homogeneous process. The main advantage is that, it requires lower investment costs, since no need for separation steps of methanol/catalyst, biodiesel/catalyst and glycerine/catalyst. This work …

Study On The Activity Of New Amine Based Absorbents For Co2 Absorption From Flue Gases, João F. Gomes

João F Gomes

The capture of CO2 from flue gases can be done by chemical absorption with aqueous amine solutions like MEA (monoethanolamine). Although this is a proven process, there are still operational problems to overcome [1], namely those resulting from solvent degradation, precipitation, corrosion and foaming. Also, the absorption capacity of the most current amines must be improved in order to obtain a more profitable operation. It has been shown previously that relationships exist between the amine structure and the activity/capacity for CO2 absorption. The introduction of amine substituents at the α-carbon creates a carbamate instability, which causes the hydrolysis to go …

A Simulation Study On The Abatement Of Co2 Emissions By De-Absorption, João F. Gomes

João F Gomes

Due to the adverse effect of CO2 from fossil fuel combustion on the earth’s ecosystems, the most cost effective method for CO2 capture is an important area of research. The predominant process for CO2 capture currently employed by industry is chemical absorption in amine solutions. A dynamic model for the de-absorption process was developed with Monoethanolamine (MEA) solution. Henry’s law was used for modeling the vapour phase equilibrium of the CO2, and fugacity ratios calculated by the Peng Robinson equation of state (EOS) were used for H2O, MEA, N2 and O2. Chemical reactions between CO2 and MEA were included in …

Studies On The Development Of Novel Heterogeneous Catalysts For Transesterification Of Triglycerides In Biodiesel, João F. Gomes

João F Gomes

No abstract provided.

Grafika Inżynierska Ćw., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Projektowanie Procesów Biotechnologicznych Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Projektowanie I Optymalizacja Procesów Proj., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Metody Numeryczne Lab., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Odnawialne Źródła Energii W., Wojciech M. Budzianowski

Wojciech Budzianowski

No abstract provided.

Proceedings Of The Scientific Conference On Energy And It At Alvsjo Fair, Stockholm March 11-12, 2009 In Connection With The “Energitinget 2009, Dr. Erik Dahlquist, Dr. Jenny Palm

Dr. Erik Dahlquist

This book contains the proceedings from the Energy and IT conference at Alvsjo Energy conference "Energitinget" arranged by Swedish Energy Agency, with approximately 2500 visitors. The papers contain both technical and social science papers, relating to both energy efficiency in buildings and in industry.

Computation Of Jump Coefficients For Momentum Transfer Between A Porous Medium And A Fluid Using A Closed Generalized Transfer Equation, Francisco J. Valdes-Parada, José Alvarez-Ramirez, Benoît Goyeau, J. Alberto Ochoa-Tapia

Francisco J. Valdes-Parada

The momentum transfer between a homogeneous fluid and a porous medium in a system analogous to the one used by Beavers and Joseph (J Fluid Mech 30:197–207, 1967) is studied using volume averaging techniques. In this article, we present a closed generalized momentum transport equation (GTE) that is valid everywhere and is expressed in terms of position-dependent effective transport coefficients, which are computed from the solution of associated closure problems previously reported. A combination of the velocity profiles from the GTE in the definition of the excess terms that define the jump coefficients allows their computation using numerical techniques. The …

Jump Condition For Diffusive And Convective Mass Transfer Between A Porous Medium And A Fluid Involving Adsorption And Chemical Reaction, Francisco J. Valdes-Parada, Jose Alvarez-Ramirez, Benoît Goyeau, J. Alberto Ochoa-Tapia

Francisco J. Valdes-Parada

In this paper, mass transfer at the fluid–porous medium boundaries is studied.The problem considers both diffusive and convective transport, along with adsorption and reaction effects in the porous medium. The result is a mass flux jump condition that is expressed in terms of effective transport coefficients. Such coefficients (a total dispersion tensor and effective reaction and adsorption coefficients) may be computed from the solution of the corresponding closure problem here stated and solved as a function of the Péclet number (Pe), the porosity and a local Thiele modulus. For the case of negligible convective transport (i.e., Pe << 1), the closure problem reduces to the one recently solved by the authors for diffusion and reaction between a fluid and a microporous medium.