Energy Systems Commons^™

Aspen Plus Simulation Of Biomass Gasification In A Steam Blown Dual Fluidised Bed, Wayne Doherty, Anthony Reynolds, David Kennedy

Book/Book Chapters

The efficient utilisation of biomass resources is of utmost importance. Biomass gasification offers much higher efficiencies than combustion. Gasification is a process in which a fuel is converted to a combustible gas (syngas). A dual fluidised bed gasifier known as the fast internally circulating fluidised bed (FICFB) was selected. It has been demonstrated at industrial scale and data is readily available for model validation. An Aspen Plus model was developed to simulate the FICFB gasifier. The model is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it. The model has been validated and …

The Role Of Transport Phenomena In The Direct Oxidation Of Solid Fuels, Charles J. Banas

Master's Theses

Direct carbon fuel cells have shown promise for stationary power generation by utilizing the direct oxidation of a solid carbon fuel source at the anode. In laboratory settings, researchers have reported up to 300mA/cm2 of current density from these cells types which suffer from mass transport losses. This paper studies the surface properties of the solid fuel source, and describes the process of CO2 evolution through an analogy to pool boiling. In nucleate boiling (a subset of pool boiling) vapor bubbles grow from nucleation sites where gas are trapped in micro-cavities on the surface. Carbon surfaces possess these same features, …

Analysis Of Biomass/Coal Co-Gasification For Integrated Gasification Combined Cycle (Igcc) Systems With Carbon Capture, Henry A. Long Iii

LSU New Orleans Theses and Dissertations

In recent years, Integrated Gasification Combined Cycle Technology (IGCC) has become more common in clean coal power operations with carbon capture and sequestration (CCS). Great efforts have been spent on investigating ways to improve the efficiency, reduce costs, and further reduce greenhouse gas emissions. This study focuses on investigating two approaches to achieve these goals. First, replace the subcritical Rankine steam cycle with a supercritical steam cycle. Second, add different amounts of biomass as feedstock to reduce emissions. Finally, implement several types of CCS, including sweet- and sour-shift pre-combustion and post-combustion.

Using the software, Thermoflow®, this study shows that utilizing …

Evaluation Of Cathode Materials For Low Temperature (500-700c) Solid Oxide Fuel Cells, Alexander M. Lassman

Master's Theses

Solid oxide fuel cells (SOFC) have gained a great deal of interest, due to their potential for high efficiency power generation and ability to utilize hydrogen fuel, as well as various hydrocarbon-based fuels. A recent trend in SOFC development has been towards lower operating temperatures (500-700°C), which can substantially reduce the cost and complexity of the system. This thesis presents an investigation into state of the art Ba- and La- based cathode materials for use in low temperature (500-700°C) solid oxide fuel cells.

Synthesis of A-site deficient [A=0.97] Ba_0.5Sr_0.5Co_0.8Fe_0.2O₃ (BSCF) was …

Applied Control Strategies At A Cogeneration Plant, Joseph William Burns

Master's Theses

The purpose of this paper is to demonstrate the effectiveness of “classical strategies for dynamic control” on authentic cogeneration processes. These strategies are applied to several processes at the University of Connecticut’s cogeneration plant. Case studies of their applications are presented in this paper. Strategies that are applied include the following:

1) The classical SISO feedback structure

2) The First Order Plus Dead Time (FOPDT) process model

3) The Internal Model Control (IMC) correlations for PI controller tuning

4) Static feed forward with feedback trim

5) Cascade Control

Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason R. Hattrick-Simpers, Wilbur S. Hurst, Sesha S. Srinivasan, James E. Maslar

Faculty Publications

An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storagematerials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element …

Mechanical Characterization Of Polymer Electrolyte Membrane With Optical Methods, Xinyu Huang, Luis Alva, Jay Neutzler

Faculty Publications

Mechanical properties of polymer electrolyte membrane have important implications in the endurance of many electrochemical energy conversion devices [1]. Mechanical experiments are effective method to reveal discrete damage developed in the membrane by quantifying the change of mechanical strength and toughness. Regular strain measurement methods are overly intrusive to the thin and relatively fragile polymer electrolyte membrane; hence optical-based minimal invasive stress/strain measurement methods are studied.

Development Of Pilot Plant For Bio-Ethanol Processing, Emrod Elisante

Tanzania Journal of Engineering and Technology (TJET)

The paper outlines achievements obtained in developing a pilot bio-ethanol plant at the Department of Chemical and Mining Engineering (CME), University of Dar es Salaam. The pilot plant consists of: 30 L inoculums tank; 1,700 L fermenter; 1,500 L/day distillation column; and ancillary equipment. The prototype is a platform intended to be used for technology demonstration and research by graduate and undergraduate students studying the production of bio-ethanol using traditional and non-traditional raw materials like coffee mash, cashew fruit, and sisal inulin. The equipment has been developed using locally available engineering resources and the distillation column with 18 sieve tray …

Computer Simulation Of A Biomass Gasification-Solid Oxide Fuel Cell Power System Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

The operation and performance of a solid oxide fuel cell (SOFC) stack on biomass syn-gas from a biomass gasification combined heat and power (CHP) plant is investigated. The objective of this work is to develop a model of a biomass-SOFC system capable of predicting performance under diverse operating conditions. The tubular SOFC technology is selected. The SOFC stack model, equilibrium type based on Gibbs free energy minimisation, is developed using Aspen Plus. The model performs heat and mass balances and considers ohmic, activation and concentration losses for the voltage calculation. The model is validated against data available in the literature …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syngas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack was modelled and its operation on biomass syn-gas was investigated. The objective of this work was to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack was modelled using Aspen Plus and considers ohmic, activation and concentration losses. It was validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor U_f and U_a, current density j and steam to carbon ratio STCR were varied and …

Temperature Influence And Heat Management Requirements Of Microalgae Cultivation In Photobioreactors, Thomas Hagen Mehlitz

Master's Theses

Microalgae are considered one of the most promising feedstocks for biofuel production for the future. The most efficient way to produce vast amounts of algal biomass is the use of closed tubular photobioreactors (PBR). The heat requirement for a given system is a major concern since the best algae growth rates are obtained between 25-30 °C, depending on the specific strain. A procedure to determine temperature influence on algal growth rates was developed for a lab-scale PBR system using the species Chlorella. A maximum growth rate of 1.44 doublings per day at 29 °C (optimal temperature) was determined. In addition, …

Simulation Of A Tubular Solid Oxide Fuel Cell Stack Operating On Biomass Syn-Gas Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Articles

A tubular solid oxide fuel cell (SOFC) stack is modelled and its operation on biomass syn-gas is investigated. The objective of this work is to develop a computer simulation model of a biomass gasification-SOFC (BG-SOFC) system capable of predicting performance under various operating conditions and using diverse fuels. The stack is modelled using Aspen Plus and considers ohmic, activation and concentration losses. It is validated against published data for operation on natural gas. Operating parameters such as fuel and air utilisation factor (U_f and U_a), current density (j) and steam to carbon ratio ( …

Inhomogeneous Degradation Of Polymer Electrolyte Membrane In Pem Fuel Cells, Xinyu Huang, Wonseok Yoon

Faculty Publications

Membrane durability is one of the technical barriers for the commercialization of polymer electrolyte membrane (PEM) fuel cells. Membrane embrittlement (a form of mechanical weakening) can lead to the frequently observed “sudden death” behavior of PEM fuel cells. It is the objective of this study to explore the fundamental mechanisms of the mechanical weakening of perfluorosulfonic acid (PFSA) based electrolyte membranes during the accelerated degradation test.

Modelling And Simulation Of A Biomass Gasification-Solid Oxide Fuel Cell Combined Heat And Power Plant Using Aspen Plus, Wayne Doherty, Anthony Reynolds, David Kennedy

Conference Papers

In this paper the operation and performance of a high temperature solid oxide fuel cell (SOFC) stack on biomass syn-gas from a demonstration biomass gasification combined heat and power (CHP) plant is investigated. The objective of this work is to develop a computer simulation model of a biomass-SOFC CHP system, flexible enough for use in industry, capable of predicting system performance under various operating conditions and using diverse fuels. The biomass gasifier is of the dual fluidised bed (DFB) type with steam as the gasifying agent and is operated at atmospheric pressure. The tubular SOFC configuration, developed by Siemens Power …

Simulation Of A Circulating Fluidised Bed Biomass Gasifier Using Aspen Plus: A Performance Analysis, Wayne Doherty, Anthony Reynolds, David Kennedy

Conference Papers

In the near future biomass gasification is likely to play an important role in energy production and conversion. Its application has great potential in the context of climate change mitigation, increasing efficiency and energy security. Atmospheric circulating fluidised bed (CFB) technology was selected for the current study. An original computer simulation model of a CFB biomass gasifier was developed using ASPEN Plus (Advanced System for Process ENgineering Plus). It is based on Gibbs free energy minimisation and the restricted equilibrium method was used to calibrate it against experimental data. This was achieved by specifying the temperature approach for the gasification …

Accelerated Testing Method For Pem Fuel Cell Based Uninterrupted Power Supply Systems, Xinyu Huang, Xiaofeng Wang

Faculty Publications

Proton exchange membrane fuel cell based power systems are on the verge of commercialization for a number of niche applications where batteries are traditionally used. Uninterrupted power supply (UPS) for wireless communication towers and broadband network relay utilities is one of the targeted application of fuel cell power systems with capacity ranging from one to serveral kilowatts. It is believed that fuel cell based UPS systems can offer considerable advantage when extended backup time is desirable. In order to replace the well-known battery based UPS systems, the reliability and perofrmance of fuel cell based UPS system need to be thoroughly …

Socio-Economic Impacts Of Computer Viruses In Tanzania, M Victor

Tanzania Journal of Engineering and Technology (TJET)

This paper reports on a research project conducted with an objective of identifying and assessing various approaches used by different computer users (Management, System Administrators and end users) in Tanzania to combat computer viruses (CVs), and to assess users' awareness level on CVs. Specifically, the study aimed at assessing the awareness level on CVs to the Tanzanian business community; analyze the socio -economic impact caused by CVs in Tanzania and; assess existing methods, capacity and limitations on controlling CVs in Tanzania. Data was collected using both questionnaires and interview from financial institutions such as NBC and BOT, and telecommunications sector …

Review Of The Product Development Process And Information Flow In The Manufacturing Industry: Problems And A Possible Wav Forward, E Opiyo

Tanzania Journal of Engineering and Technology (TJET)

No abstract provided.

Indirect Evaporative Cooling Potential In Air-Water Systems In Temperate Climates, Ben Costelloe, Donal Finn

Articles

Recent developments have prompted a review of evaporative cooling technology as an effective means of cooling modern deep plan buildings. Prominent among these developments is the success of high temperature sensible cooling systems, particularly, chilled ceilings, which require a supply of cooling water at 14–18 °C. Crucial to the success of evaporative cooling technology, as a significant means of cooling in modern applications, is the ability to generate cooling water, in an indirect circuit, at a temperature which closely approaches the ambient adiabatic saturation temperature (AST) or wet bulb temperature (WBT). Recent experimental research has demonstrated that it is technically …

Application Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Arton Of Vibrational Techniques In Determination Of Dynamic Properties Of Agricultural Products-State Of The Art, Silas Kajuna

Tanzania Journal of Engineering and Technology (TJET)

Vibration is one of the techniques employed in the determination of dynamic properties of fruits and vegetables. It entails generation of a mechanical or acoustic vibrational signal which is propagated through the flesh of the agricultural material. A transducer is either attached or held close to the specimen to monitor the propagation of the signal through the specimen. The manner in which the signal is transmitted through the material is analyzed, and the dynamic properties of the specimen which relate to its firmness or its internal being are derived. The technique has been around for the past 30 years or …

Entropy Generation In A Rectangular Packed Duct With Wall Heat Flux, Yaşar Demirel, Ramazan Kahraman

Papers in Thermal Mechanics

The entropy generation due to heat transfer and friction has been calculated for fully developed, forced convection flow in a large rectangular duct, packed with spherical particles, with constant heat fluxes applied to both the top (heated) and bottom (cooled) wall. An approximate analytical expression for the velocity profile developed for packed bed with H/dp > 5 has been used together with the energy equation of fully developed flow to calculate the non isothermal temperature profiles along the flow passage. The velocity profile takes into account the increase in the velocity near the wall due to the higher voidage in this …

Fuel Cells, Frederick J. Munster Jr.

Maine Collection

Fuel Cells

by Frederick J. Munster Jr.

Edited by: Mr. Christopher Carroll

Maine Department of Economic Development, Augusta, Maine, 1998.

Contents: Hydrogen / Hydrogen Safety / Electrolysis / Electrolyzers / History of Fuel Cells / How Fuel Cells Operate / Fuel Cell Types / Fuel Cell Electrochemistry / Power Systems / Fuel Cells in Transportation / Hydrogen Powered Internal Combustion Engines / Home, Garden, Education and Industry / For More Information / Glossary / References

A Study Of The Thermodynamic And Heat Transfer Characteristics Of Two-Phase Two-Component Flow With Application To A Solar-Assisted Heat Pump, Walid A. Aziz

Mechanical & Aerospace Engineering Theses & Dissertations

Two-phase flow of single component refrigerants has been studied, theoretically and experimentally, for many CFCs, in many industrial applications, including the solar-assisted heat pump system. This study extends the thermodynamic and heat transfer analysis in the phase transition boiling region, to newly proposed refrigerant mixtures, which are candidates for replacing the classical CFCs for future HVAC applications. The goal of this study is to develop a methodology, to design the collector/evaporator tubes of a solar-assisted heat pump, using a binary refrigerant mixture as the working fluid. The method is implemented numerically as a computer algorithm. In order to do that, …

A Mathematical Model And Simulation Of Natural Circulation Loop Thermalhydraulics, Nihad E. Daidzic

Aviation Department Publications

In this work, a simple, nonlinear, seventh-order mathematical model with lumped parameter analysis of the thermalhydraulic processes in a natural circulation steam boiler loop is presented. Digital simulation has been performed in order to predict open loop transients in severe accidental situations. Parts of the circulation loop such as the steam drum, downcomer, and riser were modelled separately on the basis of the integral balance equations. The two-phase flow in the steam drum and in the riser was modelled with the aid of a homogeneous-equilibrium, two-phase flow model. Special care was taken to ensure the stability of the numerical scheme, …

Comparative Residential Energy Consumption And Fuel Costs With Various Types Of Systems: Oil-, Gas-, Electric-Furnaces And Heat Pumps, Ronald Hunter Howell, Harry J. Sauer Jr.

UMR-MEC Conference on Energy / UMR-DNR Conference on Energy

The electric air-to-air heat pump for residential heating offers an economic alternative to systems traditionally used extensively for home heating, such as, oil or gas fired furnaces and electric resistance heat. This simulation analysis showed that using 1976 mid- Missouri fuel costs, an oil fired furnace was the least expensive to operate of the three traditional type residential heating units. LP gas heating was 19% higher than oil heat while electric resistance heating was 26% higher in cost than oil. The typical air-to- air heat pumps showed a 29% reduction in the heating bill when compared to an oil furnace.