Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report
This program aims at developing mathematical models, and computer codes based on these models, which will allow prediction of the product distribution in chemical reactors in which gaseous silicon compounds are converted to condensed-phase silicon. The reactors to be modeled are flow reactors in which silane or one of the halogenated silanes is thermally decomposed or reacted with an alkali metal, H/sub 2/ or H atoms. Because the product of interest is particulate silicon, processes which must be modeled, in addition to mixing and reaction of gas-phase reactants, include the nucleation and growth of condensed Si via coagulation, condensation, and heterogeneous reaction. During this report period computer codes were developed and used to calculate: (1) coefficients for Si vapor and Si particles describing transport due to concentration and temperature gradients (i.e., Fick and Soret diffusion, respectively), and (2) estimates of thermochemical properties of Si n-mers. The former are needed to allow the mass flux of Si to reactor walls to be calculated. Because of the extremely large temperature gradients that exist in some of the reactors to be used in producing Si (particularly the Westinghouse reactor), it was found that thermal (Soret) diffusion can be the dominant transport mechanism for certain sizes of Si particles. The thermochemical estimates are required to allow computation of the formation rate of Si droplets. With the completion of these calculations the information and coding of the particle routines in the modified LAPP code is at the point where debugging can be done and that is now in progress.
- Research Organization:
- Aerochem Research Labs., Inc., Princeton, NJ (USA)
- DOE Contract Number:
- NAS-7-100-954862
- OSTI ID:
- 5985587
- Report Number(s):
- DOE/JPL/954862-5; AeroChem-TN-202
- Country of Publication:
- United States
- Language:
- English
Similar Records
Development of a model and computer code to describe solar grade silicon production processes. Third quarterly report, April 1, 1978--June 30, 1978
Development of a model and computer code to describe solar grade silicon production processes. Second quarterly report, January 1--March 31, 1978
Related Subjects
36 MATERIALS SCIENCE
SILICON
PRODUCTION
CHEMICAL REACTORS
COMPUTER CALCULATIONS
COMPUTER CODES
HYDROGENATION
MASS TRANSFER
MATHEMATICAL MODELS
NUCLEATION
PARTICLES
SILANES
SILICON SOLAR CELLS
TEMPERATURE GRADIENTS
THERMAL DIFFUSION
THERMODYNAMIC PROPERTIES
CHEMICAL REACTIONS
DIFFUSION
DIRECT ENERGY CONVERTERS
ELEMENTS
HYDRIDES
HYDROGEN COMPOUNDS
PHOTOELECTRIC CELLS
PHOTOVOLTAIC CELLS
PHYSICAL PROPERTIES
SEMIMETALS
SILICON COMPOUNDS
SOLAR CELLS
140501* - Solar Energy Conversion- Photovoltaic Conversion
360601 - Other Materials- Preparation & Manufacture