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Preliminary result of a three dimensional numerical simulation of cloud formation over a cooling pond

Description: Cooling ponds receive large amounts of waste heat from industrial sources and release the heat to the atmosphere. These large area sources of warm and moist air may have significant inadvertent effects. This paper is a preliminary step in the development of a method for estimating the perturbations in the atmosphere produced by a cooling pond. A three-dimensional numerical model based on turbulence second-moment closure equations and Gaussian cloud relations has been developed. A simplified version of the model, in which only turbulent energy and length-scale equations are solved prognostically, is used. Numerical simulations are conducted using as boundary conditions the data from a cooling pond study conducted in northern Illinois during the winter of 1976-1977. Preliminary analyses of these simulations indicate that formation of clouds over a cooling pond is sensitive to the moisture content in the ambient atmosphere.
Date: January 1, 1978
Creator: Yamada, T.
Partner: UNT Libraries Government Documents Department

Process feasibility study in support of silicon material, Task I. Quarterly technical progress report (XI)

Description: Major activities focused on process system properties, chemical engineering and economic analyses during this reporting period. Analysis of process system properties was continued for silicon source materials. Primary efforts centered on data collection, analysis, estimation and correlation. Property data for silicon tetrachloride are reported for critical constants (temperature, pressure, volume, compressibility factor); vapor pressure; heat of vaporization; gas heat capacity and liquid heat capacity. Silicon tetrachloride is the source material in several processes under consideration for solar cell grade silicon production. Final experimental values for gas phase thermal conductivity of the silicon source materials silane, dichlorosilane, trichlorosilane, tetrachlorosilane, and tetrafluorosilane are reported in the temperature range 25 to 350/sup 0/C. These final values reflect a refinement of previously reported preliminary values after complete calibration of the temperature measuring apparatus. Chemical engineering analysis of the Union Carbide silane process (Case C-Revised Process) was continued with primary efforts being devoted to the preliminary process design. Status and progress are reported for base case conditions, process flow diagram, reaction chemistry and equipment design. Current engineering design is in progress for the several distillation columns which separate the liquid chlorosilanes and provide purified silane product.
Date: June 1, 1978
Creator: Fang, C.S.; Hansen, K.C.; Miller, J.W. Jr. & Yaws, C.L.
Partner: UNT Libraries Government Documents Department

Measurement of alkali-vapor emission from pressurized fluidized-bed combustion of Illinois coals

Description: Two Illinois Herrin No. 6 coals and one Illinois Springfield No. 5 coal were separately combusted in a laboratory-scale (15-cm dia) pressurized fluidized-bed combustor (PFBC) combined with an alkali sorber. These coals were combusted in a fluidized bed of Tymochtee dolomite at temperatures ranging from 910 to 950[degree]C and a system pressure of 9.2 atm absolute. Alkali-vapor emission (Na and K) in the PFBC flue gas was determined by the analytical activated-bauxite sorber bed technique developed at Argonne National Laboratory. The test results showed that sodium is the major alkali-vapor species present in the PFBC flue gas, and that the level of sodium-vapor emission increases linearly with both Na and Cl contents in the coals. This suggests that the sodium-vapor emission results from direct vaporization of NaCl present in the coals. The measured alkali-vapor concentration (Na + K), 67 to 190 ppbW, is more than 2.5 times greater than the allowable alkali limit of 24 ppb for an industrial gas turbine. Combusting these coals in a PFBC for power generation may require developing a method to control alkali vapors.
Date: January 1, 1993
Creator: Lee, S.H.D.; Teats, F.G.; Swift, W.M. (Argonne National Lab., IL (United States)) & Banerjee, D.D. (Illinois Clean Coal Inst., Carterville, IL (United States))
Partner: UNT Libraries Government Documents Department

Analysis of fission product revaporization in a BWR Reactor Coolant System during a station blackout accident

Description: This paper presents an analysis of fission product revaporization from the Reactor Coolant System (RCS) following the Reactor Pressure Vessel (RPV) failure. The station blackout accident in a BWR Mark I Power Plant was considered. The TRAPMELT3 models for vaporization, chemisorption, and the decay heating of RCS structures and gases were used and extended beyond the RPV failure in the analysis. The RCS flow models based on the density-difference or pressure-difference between the RCS and containment pedestal region were developed to estimate the RCS outflow which carries the revaporized fission product to the containment. A computer code called REVAP was developed for the analysis. The REVAP code was incorporated with the MARCH, TRAPMELT3 and NAUA codes from the Source Term Code Package (STCP) to estimate the impact of revaporization on environmental release. The results show that the thermal-hydraulic conditions between the RCS and the pedestal region are important factors in determining the magnitude of revaporization and subsequent release of the volatile fission product into the environment. 6 refs., 8 figs.
Date: January 1, 1988
Creator: Yang, J.W.; Schmidt, E.; Cazzoli, E. & Khatib-Rahbar, M.
Partner: UNT Libraries Government Documents Department

Study of falling-jet flash evaporators

Description: Experimental results of flash evaporation from sheets of water, 3.2 mm and 6.3 mm thick and 27.9 cm wide, falling freely in the presence of their own vapor, are reported. With no flashing the jets fall in coherent sheets, but with flashing the jets were observed to spread and break up into droplets. Flashing was characterized by an effectiveness parameter, which was found to increase with increasing water temperature and jet length. Variations in water flow rate and heat flux did not influence the effectiveness appreciably.
Date: November 1, 1982
Creator: Kreith, F.; Olson, D.A.; Bharathan, D. & Green, H.J.
Partner: UNT Libraries Government Documents Department

FEM3A simulations of selected LNG vapor barrier verification field tests

Description: In order to evaluate and eventually predict the possible mitigating effects of vapor fences on the dispersion of the vapor cloud resulting from an accidental liquefied natural gas (LNG) spill in storage areas, a research program was initiated to evaluate methods for predicting LNG dispersion distances for realistic facility configurations. As part of the program, Lawrence Livermore National Laboratory (LLNL) conducted a series of large-scale field experiments called the LNG Vapor Barrier Verification Field Trials (also referred to as the Falcon Series) at the Liquefied Gaseous Fuels Spill Test Facility (LGFSTF), Nevada. Objectives were (1) to provide a data base on LNG vapor dispersion from spill involving complex field obstacles to assist in validation of wind tunnel and mathematical models, and (2) to assess the effectiveness of vapor fences for mitigating LNG vapor dispersion hazards in the events of an accidental spill. Five spill experiments were conducted on water in order to generate vapor at rates equivalent to the liquid spill rates. In this study, the FEM3A model was applied to simulate four of the Falcon experiments. The objectives of this study were, through numerical modeling and a detailed model-data comparison: (1) to improve our understanding of LNG vapor dispersion involving vapor barriers, (2) to assess FEM3A in modeling such complex vapor dispersion scenarios, and (3) to complement the results of field and wind tunnel tests, such as providing plausible explanations for unexpected results and filling in data gaps due to instrument failure or limited array size. Toward these goals, the relevant field measurements were analyzed and several series of 2-D and 3-D simulations were carried out. 11 refs., 93 figs., 11 tabs.
Date: October 1, 1990
Creator: Chan, S. T.
Partner: UNT Libraries Government Documents Department

Iodine and NO sub x behavior in the dissolver off-gas and IODOX (Iodine Oxidation) systems in the Oak Ridge National Laboratory Integrated Equipment Test facility

Description: This paper describes the most recent in a series of experiments evaluating the behavior of iodine and NO{sub x} in the Integrated Equipment Test (IET) Dissolver Off-Gas (DOG) System. This work was performed as part of a joint collaborative program between the US Department of Energy and the Power and Nuclear Fuel Development Corporation of Japan. The DOG system consists of two shell-and-tube heat exchangers in which water and nitric acid are removed from the dissolver off-gas by condensation, followed by a packed tower in which NO{sub x} is removed by absorption into a dilute nitric acid solution. The paper also describes the results of the operation of the Iodine Oxidation (IODOX) System. This system serves to remove iodine from the DOG system effluent by absorption into hyperazeotropic nitric acid. 7 refs., 11 figs., 10 tabs.
Date: January 1, 1990
Creator: Birdwell, J. F.
Partner: UNT Libraries Government Documents Department

Vaporization, dispersion, and radiant fluxes from LPG spills. Final technical report

Description: Both burning and non-burning spills of LPG (primarily propane) were studied. Vaporization rates for propane spills on soil, concrete, insulating concrete, asphalt, sod, wood, and polymer foams were measured. Thermal conductivity, heat transfer coefficients, and steady state vaporization rates were determined. Vapor concentrations were measured downwind of open propane pools and a Gaussian dispersion model modified for area sources provided a good correlation of measured concentrations. Emitted and incident radiant fluxes from propane fires were measured. Simplified flame radiation models were adequate for predicting radiant fluxes. Tests in which propane was sprayed into the air showed that at moderately high spray rates all the propane flashed to vapor or atomized; no liquid collected on the ground.
Date: May 1, 1982
Partner: UNT Libraries Government Documents Department

Development of standardized air-blown coal gasifier/gas turbine concepts for future electric power systems

Description: CRS Sirrine (CRSS) is evaluating a novel IGCC process in which gases exiting the gasifier are burned in a gas turbine combustion system. The turbine exhaust gas is used to generate additional power in a conventional steam generator. This results in a significant increase in efficiency. However, the IGCC process requires development of novel approaches to control SO{sub 2} and NO{sub x} emissions and alkali vapors which can damage downstream turbine components. Ammonia is produced from the reaction of coal-bound nitrogen with steam in the reducing zone of any fixed bed coal gasifier. This ammonia can be partially oxidized to NO{sub x} when the product gas is oxidized in a gas turbine combustor. Alkali metals vaporize in the high-temperature combustion zone of the gasifier and laser condense on the surface of small char or ash particles or on cooled metal surfaces. It these alkali-coated materials reach the gas turbine combustor, the alkali will revaporize condense on turbine blades and cause rapid high temperature corrosion. Efficiency reduction will result. PSI Technology Company (PSIT) was contracted by CRSS to evaluate and recommend solutions for NO{sub x} emissions and for alkali metals deposition. Various methods for NO{sub x} emission control and the potential process and economic impacts were evaluated. This included estimates of process performance, heat and mass balances around the combustion and heat transfer units and a preliminary economic evaluation. The potential for alkali metal vaporization and condensation at various points in the system was also estimated. Several control processes and evaluated, including an order of magnitude cost for the control process.
Date: July 1, 1990
Partner: UNT Libraries Government Documents Department

Transformations of inorganic coal constituents in combustion systems

Description: The technical objectives of this project are: (1) To define the partitioning of inorganic constituents associated with raw coal particles among products (including vapors, aerosols, and residual char/ash particles) formed under conditions representative of pulverized coal flames as a function of the specific (intrinsic and extrinsic) characteristics of the raw coal and the environment in which the transformations occur; and to characterize the resultant spectrum of products in detail. (2) To elucidate and quantify the fundamental processes (involving basic principles of physics, chemistry, thermodynamics) by which transformations of the inorganic constituents occur; and (3) to develop, based on the information required in (1) and (2), a tractable process'' model capable of predicting the significant features of the transformation process, most importantly, the nature and distribution of products. 26 refs., 151 figs., 51 tabs.
Date: September 1, 1991
Creator: Helble, J.J.; Srinivasachar, S.; Wilemski, G.; Boni, A.A. (PSI Technology Co., Andover, MA (United States)); Kang, Shin-Gyoo; Sarofim, A.F. et al.
Partner: UNT Libraries Government Documents Department