Begell House Inc.
International Journal of Energy for a Clean Environment
IJECE
2150-3621
5
2
2004
MULTI-CRITERIA SUSTAINABILITY ASSESSMENT OF CLEAN AIR TECHNOLOGIES
18
10.1615/InterJEnerCleanEnv.v5.i2.10
Naim Hamdia
Afgan
Instituto Superior Tecnico
Department of Mechanical Engineering
Av. Rovisco Pais, 1049-001 Lisbon Portugal
Nikolai V.
Hovanov
St. Petersburg State University, St. Petersburg, Russia
This article presents a selection of criteria and options for the assessment of clean air energy technologies, based on the Analysis and Synthesis of Parameters using the Information Deficiency Method. In order to present an evaluation of clean air technologies, a number of options featuring some of the characteristics measured by the selected sustainability indicators are taken into consideration. For each option under consideration, the sustainability indicators are defined in order to verify their rating with respect to the specific indicator and also to introduce these data to obtain a generalized index of sustainability that rates all options.
The multi-criteria evaluation of clean air technologies is an exercise to illustrate the potential of the analysis of complex systems. Every energy system under consideration is an entity in itself, defined by the respective number of parameters, which are deterministically related according to physical laws describing individual processes in the system. The sustainability indicators take into account the economic, environmental, resource, and social aspects of the system under consideration.
EFFECT OF A MAGNETIC FIELD ON DIFFUSION FLAMES, CO2 AND NOx GAS STREAMS
20
10.1615/InterJEnerCleanEnv.v5.i2.20
Hidenori
Tanaka
The National Defense Academy, Department of Applied Physics, 1-10-20, Hashirimizu, Yokosuka, 239 -8686 JAPAN
Atsushi
Saima
Department of Mechanical Engineering, College of Science and Technology, Nihon University, 1-8, Kanda Surugadai, Chiyodaku, Tokyo 101-8308, Japan
The pressure effect on diffusion flames, CO2 gas flow, and diluted NOx gas flow were investigated in a magnetic field. The flame deformation and the inclination of the flame axis were examined. Magnetic field strength was changed from 0 up to 10.35 × 105 A/m. Experiments in the flame deformation were carried out at two positions in the field, and those of the inclination were carried out in the neighborhood of the pole edge. The deformation of flames of these gases and the inclination were attributed to paramagnetic (air) and diamagnetic properties (flame, CO2 gas, and NOx gas). At the inflection point of the flame axis, the inclination angle θ of the flame axis was decided by two forces, the magnetic force FHξ and the buoyant force FB. Experimental results of the inclination of the flame axis showed good agreement with the theoretical analysis. The jet path of CO2 gas was numerically investigated. The original path changed as the magnetic field was applied. The position of the peak of the velocity on the cross section of the jet shifted to the side of the small magnetic field strength. In the stream of NOx, the path approached to the pole piece. These results were proposed as a cleaning technology in the handling of combustion gas and exhaust gas.
DECOMPOSITION OF SELECTED ORGANIC WASTES DURING OXIDATION IN SUPERCRITICAL WATER
14
10.1615/InterJEnerCleanEnv.v5.i2.30
Sikun
Xu
Energy and Environmental Research Laboratory, Department of Minerals & Materials Engineering, McGill University, 3610 University Street, Wong Building, RM 2160, Montreal, QC H3A 2B2, Canada
Zhen
Fang
Energy and Environmental Research Laboratory, Department of Minerals & Materials Engineering, McGill University, 3610 University Street, Wong Building, RM 2160, Montreal, QC H3A 2B2, Canada
Janusz A.
Kozinski
Department of Chemical Engineering, 3b48 Engineering Building, University of Saskatchewan, 57 Campus Drive, Saskatoon SKS7N5A9 Canada
This research focused on the destruction of naphthalene, representing Polycyclic Aromatic Hydrocarbons (PAHs), using supercritical water (SCW). Experiments were conducted in a Diamond Anvil Cell (DAC) and a batch reactor. The results show that naphthalene can be completely dissolved in supercritical water at 424°C, following the formation of a homogeneous phase. Oxidation of naphthalene takes place in three stages, accompanied by the formation of complex intermediates. Heavier compounds, such as dibenzofuran, fluorenone, and xanthone, are produced during oxidation. All intermediates and naphthalene are oxidized to CO2 and H2O during ~1800 s reaction time. The partial reaction pathways are identified.
EXPERIMENTAL INVESTIGATION OF NATURAL GAS COMBUSTION IN OXYGEN/EXHAUST GAS MIXTURES FOR ZERO EMISSIONS POWER GENERATION
16
10.1615/InterJEnerCleanEnv.v5.i2.40
R.
Carroni
ALSTOM Power Technology Ltd. Center, Segelhof CH-5405, Baden-Daettwil, Switzerland
M.
Reinke
Paul Scherrer Institute, Combustion Research, CH-5232, Villigen PSI, Switzerland
D.
Winkler
ALSTOM Power Technology Ltd. Center, Segelhof CH-5405, Baden-Daettwil, Switzerland
T.
Griffin
ALSTOM Power Technology Ltd. Center, Segelhof CH-5405, Baden-Daettwil, Switzerland
"Zero Emissions" gas turbine processes allow the generation of electrical energy without emission of CO2 to the environment. The cost of removing CO2 from combustion exhaust gases can be significantly reduced if an oxygen/exhaust gas mixture replaces the oxidant air. Combustion is thus carried out in a nearly stoichiometric natural gas/O2 mixture heavily diluted in CO2 and water vapor. The influence of this high exhaust gas dilution on the stability of natural gas combustion is investigated in this study, using both diffusion and lean-premix combustion technologies. Experiments were performed at atmospheric pressure and conditions (inlet temperatures of 450°C and 550°C, velocities, fuel concentration) relevant to gas turbines.
A STUDY ON COAL BLENDING FOR REDUCING NOx AND N2O LEVELS DURING FLUIDIZED BED COMBUSTION
16
10.1615/InterJEnerCleanEnv.v5.i2.50
D.
Boavida
DEECA-INETI, Edificio J, Estrada do Paco do Lumiar 22, 1649-038 Lisboa, Portugal
P.
Abelha
DEECA-INETI, Edificio J, Estrada do Paco do Lumiar 22, 1649-038 Lisboa, Portugal
I.
Gulyurtlu
DEECA-INETI, Edificio J, Estrada do Paco do Lumiar 22, 1649-038 Lisboa, Portugal
Bruno
Valentim
Centro de Geologia e Departamento de Geociências, Ambiente e Ordenamento do Território da Faculdade de Ciencias, Universidade do 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
The objective of the study was to investigate the effect of blending on the emissions of NOx and N2O during the fluidized bed combustion of five coals with different levels of nitrogen, volatile matter, and fixed carbon contents, and diverse coal and char petrographic composition.
The devolatilization chars were produced in a fluidized bed combustor. Using the petrographic analyses of the coals, sixteen coal blends were made to carry out the combustion tests.
The combustion of individual coals and the sixteen blends was carried out in an electrically heated atmospheric fluidized bed combustor.
The emissions of NOx reached maximum values at a bed temperature around 1173 K and decreased with lower combustion temperatures. The amount of nitrous oxide formed decreased, for all five coals, as the bed temperature increased from 1053 to 1303 K. These trends are consistent with the observed experimental data obtained by other researchers. It was observed that for ratios of 1.3 to 1.6 of fixed carbon to volatile matter, both NOx and N2O emission levels were minimal and, outside this range, both oxides showed a sharp increase in their formation/emissions. The coal blends were also found to show similar trends with increasing the bed temperatures.
The results serve to establish the relative importance of volatile and fixed carbon reactivity and coal and char petrography, which is believed to significantly contribute to devolatilization mechanisms and char reactivity.