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Title: Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report

Abstract

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 formore » 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.« less

Authors:
;
Publication Date:
Research Org.:
Aerochem Research Labs., Inc., Princeton, NJ (USA)
OSTI Identifier:
5985587
Report Number(s):
DOE/JPL/954862-5; AeroChem-TN-202
DOE Contract Number:  
NAS-7-100-954862
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; 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

Citation Formats

Srivastava, R., and Gould, R.K. Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report. United States: N. p., 1979. Web. doi:10.2172/5985587.
Srivastava, R., & Gould, R.K. Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report. United States. doi:10.2172/5985587.
Srivastava, R., and Gould, R.K. Thu . "Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report". United States. doi:10.2172/5985587. https://www.osti.gov/servlets/purl/5985587.
@article{osti_5985587,
title = {Development of a model and computer code to describe solar grade silicon production processes. Fifth quarterly report},
author = {Srivastava, R. and Gould, R.K.},
abstractNote = {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.},
doi = {10.2172/5985587},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1979},
month = {2}
}