Begell House Inc.
International Journal of Energy for a Clean Environment
IJECE
2150-3621
11
1-4
2010
OPTIMIZATION OF GAS PROCESSING IN A HIGH-TEMPERATURE PROTON EXCHANGE MEMBRANE FUEL CELL COMBINED HEAT AND POWER PLANT ON THE BASIS OF THE NUMERICAL PINCH METHOD
1-10
10.1615/InterJEnerCleanEnv.2011001404
Stephan
Anger
Institute of Thermal Engineering, TU Bergakademie Freiberg, Gustav-Zeuner-Str. 7, 09596 Freiberg, Germany
J.
Nitzsche
DBI Gas- und Umwelttechnik GmbH, Halsbrücker Straße 34, 09599 Freiberg, Germany
H.
Krause
DBI Gas- und Umwelttechnik GmbH, Halsbrücker Straße 34, 09599 Freiberg, Germany
Dimosthenis
Trimis
Institute of Thermal Engineering, Technische Universitat Bergakademie Freiberg, Gustav-Zeuner-Strasse 7, D-09596 Freiberg, Germany; Engler-Bunte-Institute Division of Combustion Technology, Karlsruhe Institute of Technology, Engler-Bunte-Ring 1, D-76131
high-temperature proton exchange membrane fuel cell
steam reforming
numerical pinch method
cogeneration of heat and power
Because of the cogeneration of heat and power within combined heat and power plants (CHPs), higher overall efficiencies are ensured that enable an efficient conversion of fossil fuels into usable energy. Owing to the increasing application of CHPs, the utilization of common power plants is reduced, leading to the minimization of exhaust gas emissions since electrical power and process heat are both utilizable where they are actually produced. In the process of a high-temperature combined heat and power plant, natural gas and water are converted into a hydrogen-rich synthesis gas by steam reforming. After a CO purification by a two-stage water-gas-shift reactor, the synthesis gas is added to the stack, where it is converted to electrical and thermal energy. Using the numerical pinch method, it is possible to obtain miscellaneous variants of internal heat transfers by determining the minimal heating and cooling demands, as well as the optimal temperatures of heating and cooling liquids. With the assistance of simulation software like ASPEN PLUS, these variants can be energetically compared by considering variable load categories. If the system is running in power-controlled mode, the accumulated heat of the stack cannot be dissipated usefully, and loss of heat takes place. Because of the temperature level of the HT-PEM (160−180°C) the application of the pinch method can demonstrate the possibility of the energetic use of this heat within the process leading to a remarkably increased electrical efficiency.
PARTICULATE MATTER EMISSION FROM OIL-FIRED DOMESTIC HEATING APPLIANCES
11-19
10.1615/InterJEnerCleanEnv.2011001457
Ralph
Edenhofer
OWI Oel-Waerme-Institute GmbH , Kaiserstr. 100, 52134 Herzogenrath, Germany
K.
Lucka
Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
H.
Koehne
OWI Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
particulate matter
PM 1
low-sulfur fuel oil
wood pellets
In order to acquire up-to-date data regarding particulate matter emissions of modern oil-fired domestic heating systems, measurements have been accomplished in the exhaust gas of two modern appliances using different fuel qualities. For comparison with solid fuels, additional measurements have been taken using a wood pellet burner. The measurement results in emission factors of less than ETSP ≈ 0.075 mg/MJ for standard heating fuel and ETSP ≈ 0.032 mg/MJ for low-sulfur heating fuel (for comparison: ETSP ≈ 10.7 mg/MJ at the wood pellet boiler) at intermittent mode of operation. Other influential parameters than the sulfur content are the type of the boiler, where the condensing boiler displays slightly lower particle emissions than the low-tem-perature boiler, and the mode of operation, which results in distinctly lower values for steady-state operation. The addition of up to 20% fatty acid methyl esters (FAME) in the fuel does not have a significant influence on the particle emissions. The main fraction of the emitted particles is in the range below 1 μm particle size (PM 1) for all the tested fuels and blends.
PYROLYTIC AND OXIDATIVE STRUCTURES IN HDDI MILD COMBUSTION
21-34
10.1615/InterJEnerCleanEnv.2011001468
Pino
Sabia
Istituto di Ricerche Sulla Combustione, C.N.R., P. le Tecchio, No. 80, 80125, Naples, Italy
M.
De Joannon
Istituto di Ricerche sulla Combustione, C.N.R., Napoli, Italy
G.
Sorrentino
Dipartimento di Ingegneria Chimica, Università Federico II, P. le Tecchio, No. 80, 80125, Naples, Italy
G.
Cozzolino
Dipartimento di Ingegneria Chimica, Università Federico II, P. le Tecchio, No. 80, 80125, Naples, Italy
Antonio
Cavaliere
Dipartimento di Ingegneria Chimica, Università di Napoli "Federico II", Naples, Italy
counterflow diffusion flames
HDDI
HODF
HODO
The typical structure of un-premixed counter-diffusion flames in standard conditions can be significantly modified when injected flows are diluted and/or pre-heated.
The increase of the fuel and/or oxidant flow dilution up to extreme conditions can lead to the formation of nonignitable mixtures. The oxidation processes can be sustained just in case the pre-heating temperature of one flow is high enough to promote self-ignition of the system. A high initial enthalpy of flows and a low fuel and/or oxygen concentration can drastically modify the structure of the oxidative region as well as the physical and chemical kinetics with respect to conventional diffusion flame. Such operating conditions are typical of mild combustion processes. More specifically a combination of both heating and dilution of oxidant and/or fuel yields an un-premixed combustion process named Hot Diluted Diffusion Ignition (HDDI).
Numerical simulation was carried out by means of commercial codes and kinetic mechanisms available in the literature in order to analyze the change of the structures of the reactive region induced by pre-heating and dilution of flows in two different configurations.
GAS STORAGE VERSUS GAS CIRCULATION IN NORTH ATLANTIC AND GONDWANA COAL TYPES
35-50
10.1615/InterJEnerCleanEnv.2011001661
M. A. P.
Dinis
Universidade Fernando Pessoa - CIAGEB, Praça de 9 de Abril 349, 4249-004 Porto, Portugal
Cristina F.
Rodrigues
Universidade Fernando Pessoa - CIAGEB, Praça de 9 de Abril 349, 4249-004 Porto, Portugal
M. J. Lemos
De Sousa
Universidade Fernando Pessoa - CIAGEB, Praça de 9 de Abril 349, 4249-004 Porto; Academia das Ciências de Lisboa, Rua da Academia das Ciências 19, 1249-122 Lisboa, Portugal
North Atlantic-type coal
Gondwana-type coal
gas storage
gas circulation
petrography
The growing insufficiency in oil and natural gas supplies and the rise in energy consumption all over the world have created new opportunities to develop other energy products and technologies. Coal again acquired an important role in the global energy survey. International organizations are now conscious and resolved to systematically move into clean/cleaner coal technologies (CCTs) and, above all, into zero (or near zero) emission technologies (ZETs). Carbon capture and storage (CCS) technologies, acting in a complementary way to CCTs, are becoming one of the solutions to facing climate changes, permitting us not to avoid entirely but to minimize the green house gas effect (GHGE) to an acceptable level. It is also imperative to emphasize the actual crucial role of coal as a natural gas source rock and as a reservoir. Yet it is also important to understand that when coal has a high gas generation potential it does not necessarily imply that coal also has a high gas storage capacity and a high gas circulation performance. This investigation aims to compare the gas storage capacity and the gas circulation behavior between Gondwana and North Atlantic coal types. Two sets of Gondwana and North Atlantic coal types, with different ranks, were selected in the present research. Results revealed that the two sets of samples corresponded to different facies and, consequently, have different chemical and physical properties and quite different gas storage and gas circulation behaviors. In general terms, "North Atlantic-type" coals have a higher CH4 storage capacity than "Gondwana-type" coals due to differences in their petrographic characteristics, mainly in terms of vitrinite content and rank but also, although in a smaller scale, in terms of gas sorption temperatures. Diffusion coefficient values present a higher dependency on temperature changes than on gas storage capacities due to the high activation energy induced by high temperatures.
THE EFFECT OF FUEL PROPERTIES ON THE START OF INJECTION AND ENERGY RELEASE OF A COMPRESSION IGNITION ENGINE FUELED ON DIMETHYL ETHER
51-63
10.1615/InterJEnerCleanEnv.2011001753
Daniele
Cipolat
School of Mechanical Engineering, University of the Witwatersrand, Johannesburg, South Africa
bulk modulus
start of injection
energy release
rate of pressure rise
The research reported here is concerned with the replacement of diesel oil with dimethyl ether (DME) as a fuel for an unmodified compression ignition engine. The different physical properties of these fuels were found to impact on the fuel injection process and on combustion. A standard, naturally aspirated four-stroke compression ignition engine was fueled on diesel oil and then on DME. All testing was performed at the injection timing and injector opening pressure as recom-mended for diesel fueling. Constant load tests at increasing engine speeds were performed on diesel and then on dimethyl ether. Analysis of the results shows that as a result of the lower bulk modulus of DME, the rate of pressure rise of DME in the fuel line and the maximum pressure prior to injection were lower than those attained with diesel fueling. It was also found that the start of injection with DME fueling occurred later than with diesel fueling, with the result that less energy was released before top dead center.
LITHIUM BOROHYDRIDE AS A HYDROGEN STORAGE MATERIAL: A REVIEW
65-97
10.1615/InterJEnerCleanEnv.2011002432
Joydev
Manna
Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, Maharashtra, India
Manvendra
Vashistha
Pillai's Institute of Information Technology, Engineering, Media Studies and Research, New Panvel, Navi Mumbai-410206, Maharashtra, India
Pratibha
Sharma
Department of Energy Science and Engineering, Indian Institute of Technology Bombay, Powai, Mumbai - 400076, Maharashtra, India
LiBH4
hydrogen storage
destabilization
complex hydrides
hydrogenation/dehydrogenation
The major obstacle in transition to the hydrogen economy is the problem of onboard hydrogen storage. Solid-state hydrogen storage is the safest and most efficient method for hydrogen storage. Most of the metal hydrides exhibit very large volumetric storage density but less than 5 wt % gravimetric hydrogen density. Light metals such as Al, B bind with four hydrogen atoms and form together with an alkali metal an ionic or partially covalent compound called complex hydride. LiBH4 is a complex hydride with 18.5 mass % gravimetric hydrogen density and 121 kg/m3 volumetric hydrogen storage capacity. The desorption temperature of LiBH4 is greater than 470°C, thus making it difficult to use for storage applications. In addition, the conditions for reversible reaction are unfavorable. Modification of thermodynamics of the hydrogenation and dehydrogenation reaction is possible by using additives which could destabilize LiBH4 by stabilizing the dehydrogenated state. This could decrease the heat of reaction and reduce the desorption temperature at the same time, making the conditions for reversible reaction more optimum. Several additives which could destabilize LiBH4 have been reviewed.
WIND ENERGY POTENTIAL FOR POWER GENERATION OF A LOCAL SITE IN GUSAU, NIGERIA
99-116
10.1615/InterJEnerCleanEnv.2011003309
Oluseyi O.
Ajayi
Mechanical Engineering Department, Covenant University, P.M.B. 1023, Ota, Nigeria
R. O.
Fagbenle
Mechanical Engineering Department, Obafemi Awolowo University, Ile Ife, Nigeria
James
Katende
Electrical and Information Engineering Department, Covenant University, Ota, Nigeria
Joshua O.
Okeniyi
Mechanical Engineering Department, Covenant University, P.M.B. 1023, Ota, Nigeria
O. A.
Omotosho
Mechanical Engineering Department, Covenant University, P.M.B. 1023, Ota, Nigeria
clean energy
wind power
Weibull analysis
Gusau-Nigeria
wind speed data
This study was used to evaluate the wind energy potential of a meteorological site in Gusau, the capital city of Zamfara state, in Nigeria. Twenty-one years (1987−2007) of three-hourly monthly mean wind data from the Nigeria Meteorological Department were assessed and subjected to two-parameter Weibull and other statistical analyses to determine the resource potential of the site for periods of months, seasons, and years. Attempts were made to compare the mean measured data with estimated data, and the Kolmogorov-Smirnov statistics were employed to show the site's wind profile's consistence with Weibull two-parameter distribution. The results showed that the monthly values of k and c ranged between 3.9 ≤ 7.9 and 4.0 ≤ 8.3, respectively, with over 80% of all the data having values ranging between 5 and 10 m/s or more. Most probable and maximum energy-carrying wind speeds also were found to be between 3.7 and 7.7 m/s and 4.5 and 9.3 m/s, respectively, across the period. Estimated wind power densities also ranged from 69.0 (in October) to 626.2 W/m2 (in January) at 10 m height. Seasonally, the dry season experiences higher wind speeds and the period of highest wind energy harvest could be from January to June every year.
REVIEW OF NOCTURNAL COOLING SYSTEMS
117-143
10.1615/InterJEnerCleanEnv.2011003225
Kevin
Nwaigwe
University of Botswana, Plot 4775 Notwane Road, Gaborone, Botswana
C. A.
Okoronkwo
School of Engineering and Engineering Technology, Federal University of Technology, P.M.B. 1526, Owerri Imo State, Nigeria
Nnamdi V.
Ogueke
Mechanical Engineering Department, Federal University of Technology, PMB
1526, Owerri, Nigeria; Africa Centre of Excellence on Future Energy and Electrochemical Systems (ACE-FUELS), Federal University of Technology, PMB 1526, Owerri, Nigeria
E. E.
Anyanwu
Mechanical Engineering Department, Federal University of Technology, P.M.B. 1526, Owerri, Nigeria
nocturnal cooling
emissivity
transmittance
sky radiation
A review of nocturnal cooling systems for space cooling is presented. The cooling systems are grouped into two broad categories, namely, the air cooling system and the water cooling system. Their performance, uses and applications, and the factors considered for their selection are reported. Also, studies aimed at determining the quantities of net night sky radiation in different locations are reviewed. Generally, most locations can provide net night sky radiation above 40 W/m2, while the nocturnal coolers have the potential for reducing space temperatures by between 2 and 4°C and can yield 14−48% savings in the energy demand of a building. Actual field testing experience, together with the prospects and problems that affect popularization of the systems, are also presented. Possible solutions are suggested.
NUMERICAL INVESTIGATION OF BURNING AND EMISSION CHARACTERISTICS OF LAMINAR METHANE DIFFUSION FLAMES IN PREHEATED OXIDIZER
145-161
10.1615/InterJEnerCleanEnv.2011004072
R.
Sreenivasan
Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India 600036
Vasudevan R.
Raghavan
Department of Mechanical Engineering, Indian Institute of Technology Madras, Chennai, India
600036
Thirumalachari
Sundararajan
Thermodynamics and Combustion Engineering
Laboratory Department of Mechanical Engineering
Indian Institute of Technology Madras, Chennai, Tamil Nadu 600036, India
coflow diffusion flame
preheated oxidizer
detailed chemical kinetics
optically thin radiation model
emissions
Numerical investigations of burning and emission characteristics of laminar methane diffusion flames in a coflowing preheated oxidizer are presented. The preheated oxidizer stream contains hot products of combustion, such as carbon dioxide and water vapor, along with oxygen and nitrogen, and is equivalent to that obtained in an exhaust gas recirculation process. Numerical simulations are carried out using a numerical model incorporated with a C2 chemical mechanism having 25 species and 121 reactions and an optically thin radiation submodel. The numerical results are validated against the experimental results for methane-air coflow flames reported in the literature. Parametric studies have been carried out by changing the temperature and composition of the coflowing oxidizer stream. The effects of these parameters on flame height, flame stability, and emission characteristics are analyzed. It is observed that the increase in the temperature of the oxidizer has a stabilizing effect on the flame, even with a lesser concentration of oxygen in the oxidizer. By investigating the stable flame cases in which a maximum temperature of around 2000 K is achieved, it can be concluded that the preheated oxidizer stream (higher temperature and reduced oxygen) helps in significant reduction of emissions such as nitric oxide and carbon monoxide.
MICROSCALE COMBINED HEAT AND POWER SYSTEM FOR LIQUID FUELS
163-176
10.1615/InterJEnerCleanEnv.2011001539
Richard
Haas-Wittmuess
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
L.
Paesler
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
R.
Pillai
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
G.
Yildiz
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
Joerg
vom Schloss
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
K.
Lucka
Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
H.
Koehne
OWI Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
F. J.
Schulte
OTAG Vertriebs GmbH & Co. KG, 59939 Olsberg, Germany
cool flame
atomization
air staging
micro-CHP
steam engine
Conventional central power generation shows a high electrical efficiency, hut the transmission of the energy to the consumer is hindered by distribution losses. Decentralized combined heat and power (CHP) generation in proximity to the customer is an alternative to reduce transmission losses. Based on a natural gas-fired micro-CHP system, a liquid fuel burner system is developed. The modification of the natural gas system for operation with light fuel oil (no. 2) is the focus of this project. An innovative vaporization technique, i.e., cool flame vaporization, is used to create a homogenous fuel-air mixture. The combustion of the fuel-air mixture is surface stabilized, using the surface burner of the natural gas system. Different atomization techniques and nitrogen oxide reduction concepts, such as air staging and exhaust gas recirculation, were evaluated. By fulfilling stringent emission targets and safe operation in the complete power range, the concept of micro-CHP aims to achieve an efficient use of limited resources.
PRACTICAL RESULTS OF A SMALL-SCALE BURNER DEVELOPMENT
177-187
10.1615/InterJEnerCleanEnv.2011001540
L.
Paesler
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
Joerg
vom Schloss
OWI Oel-Waerme-Institut GmbH, 52134 Herzogenrath, Germany
C.
Jaschinski
Oel-Waerme Institut GmbH (OWI), 52134 Aachen-Herzogenrath, Germany
K.
Lucka
Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
H.
Koehne
OWI Oel-Wärme-Institut gGmbH, Kaiserstraße 100, D-52134 Herzogenrath, Germany
L.
Kulisiewicz
Institute of Fluid Mechanics (LSTM), University of Erlangen, 91058 Erlangen, Germany
Sabine
Ausmeier
Institute of Fluid Mechanics, University of Erlangen-Nuremberg, Cauerstrasse 4, 91058 Erlangen, Germany
Antonio
Delgado
Institute of Fluid Mechanics Friedrich-Alexander University Erlangen-Nuremberg Cauerstrasse 4, D-91058 Erlangen, Germany
cool flame
porous media combustion
compact heating system
oil burner
Modern household heating systems are expected to exhibit a low minimal power, a wide power modulation range, and a high power density. The combination of innovative concepts and technologies such as the vaporization in porous media, the preparation of a homogeneous fuel-air mixture supported by cool flames (Lucka and Köhne, 5th CleanAir, Portugal, 1999), and the combustion in inert porous media (Trimis and Durst, Combust. Sci. Technol., vol. 121, pp. 153−168, 1996) will help to meet the changed requirements. The intention of the project PyrInno is to develop an extremely compact oil heating system that reveals low emissions, a power modulation range from 1 to 8 kW, and meets the German air pollution guidelines for environmental protection. In this contribution, the operating model of this compact premix burner for light fuel oil is presented and experimental results are shown.
SYNTHESIS GAS PRODUCTION BY REFORMING METHANE IN A CHEMICAL COMPRESSION REACTOR
189-204
10.1615/InterJEnerCleanEnv.2011001596
Vladimir
Shmelev
Combustion Lab, Institution of Russian Academy of Sciences Semenov Institute of Chemical Physics RAS, Kosygin str. 4, Moscow, 119991, Russia
Y. N.
Chun
Department of Environmental Engineering, Chosun University, Republic of Korea
synthesis gas
hydrogen
reforming
chemical compression reactor
Various technologies are suggested to convert methane, a main ingredient of natural gas, into hydrogen. These investigations are part of the total efforts to develop new low-pollution energies and reduce greenhouse gases. This study, different from existing methods of reformation, suggests a first step in an approach to a partial oxidation of methane in a methane-air mixture with usage of the internal combustion engine, which can be modified to a chemical compression reactor with heat recuperation. A simple commercial diesel engine with an intake electrical heater was used for investigations. The theoretical analysis was done and the experiments were carried out with methane-air mixtures of variable equivalence ratio, and total flow rate under high intake temperature. Results showed that the concentration of hydrogen and carbon monoxide could reach almost 20 and 15%, respectively, under the optimal standard conditions with an equivalence ratio of 0.35, total flow rate of 106.5 L/min, and intake preheating temperature of 600 K. The considerable role of crankshaft speed on syngas yield was shown.
TURBULENT COUNTERFLOW INDUCED BY SWIRL DECAY
203-225
10.1615/InterJEnerCleanEnv.2011003589
Anatoli
Borissov
General Vortex Energy Inc., 1306 FM 1092 Siute 205, Missouri City, TX 77459
Vladimir N.
Shtern
General Vortex Energy Inc., Missouri City, TX 77479, USA
turbulent
swirl flow
vortex
mixing
Reynolds
averaged Navier-Stokes equation
analytical solution
Swirling counterflows occur in vortex combustors, hydrocyclones, and vortex tubes where the Reynolds number can exceed 10 × 105. It is explained here why the elongated counterflows survive wild turbulent mixing in these devices. To this end, an analytical solution to the Reynolds-averaged Navier-Stokes equations is obtained that describes the turbulent flow in a cylindrical container. The Reynolds stresses are modeled using the Prandtl mixing length approach modified here for swirling flows. A fluid enters the container through a tangential inlet and leaves through a central exhaust, both located at the same end wall. Despite the inlet and exhaust being close, there is no shortcut flow. The fluid goes from the inlet near the sidewall to the dead end, turns around, and goes back near the axis to the exhaust. This global counterflow occurs due to swirl decay caused by friction at the sidewall. The combined effects of the end wall, swirl and friction causes pressure drops from the inlet to the dead end near the sidewall and from the dead end to the exhaust near the axis. Such a pressure distribution drives the counterflow and provides its survival against turbulent mixing. A simple experiment is performed confirming the counterflow geometry.