SILICONE FROM RICE HUSK [CODE NO.3655]
Worldwide concerns over energy related climate change coupled with spiraling cost of fossil fuels in recent years has increased interests in renewable energy alternatives. Although solar photovoltaic power generation is a proven technology, especially in the space industry, development of this technology to meet terrestrial energy demands has been limited. One of the issues that have limited the widespread use of solar photovoltaic power has been the high cost associated with the materials used in fabricating the solar cells. Currently silicon in both monocrystalline and polycrystalline form is the dominant semiconductor material used in the fabrication of most commercially available solar cells or modules, commanding over 90% of the market share of all PV technologies.
Metallurgical grade and electronic or semiconductor grade silicon are produced on commercial scale by the carbothermic and Siemens process respectively. Metallurgical grade silicon is typically 98-99.5% and contains high content of electro-active impurities such as B(5-70 ppm), P(5-100ppm), Al(3000-5000 ppm) and transition metals which are recognized to reduce the conversion efficiencies of p-n junction silicon solar cells and panels. Electronic grade silicon on the other hand which has total impurities less than one part per billion (< 1ppb) is too expensive for large scale production of solar cells. For fabrication of efficient silicon solar cells it is generally recognized the B and P levels have to be reduced to less than 1ppm each and with an overall silicon feedstock purity in the range of 5-7N.
COST ESTIMATION
Plant Capacity 5 MT/Day
Land & Building (1500 sq.mt.) Rs. 2.15 Cr
Plant & Machinery Rs. 2.10 Cr
Working Capital for 1 Month Rs. 83 Lac
Total Capital Investment Rs. 5.28 Cr
Rate of Return 20%
Break Even Point 63%
INTRODUCTION
USES OF SILICON
PROPERTIES OF SILICON
FIGURE: DIAMOND CUBIC LATTICE OF CRYSTALLINE SILICON
FIGURE: DIAMOND CUBIC LATTICE OF CRYSTALLINE SILICON WITH INTERATOMIC SITES
FIGURE: ENERGY BAND OF CRYSTALLINE SILICON
FIGURE: FREE ENERGY OF FORMATION OF OXIDES OF ELEMENTS
TABLE: THERMAL AND MECHANICAL PROPERTIES OF SILICON
PROPERTIES
CHEMICAL PROPERTIES
CHARACTERISTICS AND AVAILABILITY OF RICE HUSKS
TABLE. 1 TYPICAL PROXIMATE ANALYSIS OF RICE HUSKS
COMPOSITION OF RICE HUSK ASH ON DRY BESIS
MARKET OVERVIEW OF SILICON
INCREASING DEMAND FOR ALUMINUM SILICON ALLOY
ALUMINUM ALLOYS ACCOUNT FOR THE LARGEST SHARE
ASIA-PACIFIC TO DOMINATE THE MARKET
NOTABLE DEVELOPMENTS IN THE MARKET
IMPURITIES IN BULK CRYSTALLINE SILICON
FIGURE: EFFECT OF METAL ATOM IMPURITIES ON P-TYPE SOLAR
CELLS EFFICIENCY
SOURCES OF SILICON RAW MATERIALS
SILICON MANUFACTURING TECHNOLOGIES
MANUFACTURING PROCESS OF METALLURGICAL GRADE SILICON (MG-SI)
TABLE: IMPURITIES IN METALLURGICAL GRADE SILICON
FIGURE: SCHEMATICS OF METALLURGICAL GRADE SILICON
PRODUCTION PROCESS
MANUFACTURING PROCESS OF ELECTRONIC GRADE SILICON (EG-SI)
FIGURE: SCHEMATICS OF (A) SIEMENS REACTOR AND
(B) CZOCHRALSKI CRYSTAL PULLER
SILICON PURIFICATION TECHNIQUES
MANUFACTURING PROCESS IN DETAILS
FLOW DIAGRAM
B.I.S. SPECIFICATION
COMPARISON OF SILICON FROM RICE HUSK ASH AND NATURAL QUARTZ
MATERIALS AND METHODS
TABLE: ELEMENTAL COMPOSITION OF RHA AND NATURAL QUARTZ
BEFORE AND AFTER MAGNESIUM REDUCTION
COMPOSITION OF RICE HUSK ASH
TABLE. COMPOSITION OF RICE HUSK ASH BY GEOGRAPHICAL LOCATION
PROCESSING OF RICE HUSK FOR SILICA
DIRECT INCINERATION WITHOUT PRE-TREATMENTS
FIGURE 1. RICE HUSK (A); CARBONIZED RICE HUSK
(B); COMPLETELY INCINERATED RICE HUSK (C)
FIGURE 2. A PILOT PLANT FOR RICE HUSK INCINERATION IN INDIA
PRE-TREATMENT EFFECTS ON SILICA PRODUCTION FROM RICE HUSK
HYDROTHERMAL METHOD
OTHER METHODS
BEHAVIOUR OF RICE HUSK ASH FOR PREPARATION OF HIGH PURITY SILICA
THEORETICAL CONSIDERATIONS
CURRENT RESEARCH AND DEVELOPMENT IN THE PRODUCTION OF RICE HUSK SILICA
PRODUCTION OF AMORPHOUS SILICA FROM RICE HUSK IN FLUIDISED
BED SYSTEM
PILOT-SCALE FLUIDISED BED COMBUSTOR SET-UP
FLUIDISED BED COMBUSTOR
CYCLONE
FLUIDISING AND PNEUMATIC AIR FEEDING SYSTEM
COMBUSTOR START-UP
RICE HUSK FEEDING SYSTEM
FIGURE-3: FEEDING SYSTEM OF PILOT-SCALE FLUIDISED BED COMBUSTOR
TEMPERATURE MEASUREMENT
FIGURE-4: SCHEMATIC DIAGRAM OF THERMOCOUPLE POSITION IN
A PILOT-SCALE FLUIDISED
BED COMBUSTOR
FLUE GAS SAMPLING AND ANALYSIS
MEASURING PRINCIPLE
FIGURE -6: OXYGEN MEASUREMENT PRINCIPLE
RESULTS AND DISCUSSIONS
BED PRE-HEATING AND STARTING OF COMBUSTOR
FIGURE -7: TEMPERATURE PROFILE DURING BED PRE-HEATING
EFFECT OF FLUIDIZING VELOCITY ON RICE HUSK COMBUSTION
FIGURE -8: REAL TIME TEMPERATURE PROFILE OF RICE HUSK
COMBUSTION AT 4, 5 AND 6 UMF AND B) 7 UMF FLUIDIZING VELOCITY
CONCLUSIONS
COMBUSTION STUDY IN 80-MM (INNER DIAMETER) FLUIDISED BED
COMBUSTOR SYSTEM
I) FLUIDISED BED COMBUSTOR COLUMN
II) CYCLONE
III) SCREW FEEDING SYSTEM
IV) COMPRESSED AIR SUPPLY
V) LPG SUPPLY
VI) TEMPERATURE MEASURING SYSTEM
PLATE -1: THE 80-MM INNER DIAMETER FLUIDISED BED
COMBUSTOR SYSTEM
COMBUSTION STUDY IN 210-MM (INNER DIAMETER) FLUIDISED BED
COMBUSTOR SYSTEM
I) FLUIDISED BED COMBUSTOR COLUMN
II) CYCLONE
III) COMPRESSED AIR SUPPLY
IV) LPG SUPPLY
V) RICE HUSK FEEDING SYSTEM
VI) TEMPERATURE MEASURING SYSTEM (THERMOCOUPLES
AND DATA LOGGER)
FIGURE -1: POSITIONS OF THERMOCOUPLES (T1 – T6), FEEDING PORT
AND VIEWING
PORT AT THE 210-MM INNER DIAMETER FLUIDISED BED COMBUSTOR
FIGURE -2: OVERALL SCHEMATIC DIAGRAM OF THE 210-MM INNER DIAMETER FLUIDISED
BED COMBUSTOR SYSTEM
PLATE-2: THE 210-MM INNER DIAMETER FLUIDISED BED
COMBUSTOR SYSTEM (SHOWN
WITHOUT INSULATION MATERIAL)
SUPPLIERS OF RAW MATERIALS
SUPPLIERS OF PLANT AND MACHINERY
SUPPLIERS OF CASTING MACHINE
SUPPLIERS OF MATERIAL HANDLING EQUIPMENTS
SUPPLIERS OF STORAGE VESSEL (STORAGE TANKS)
SUPPLIERS OF LABORATORY EQUIPMENTS
SUPPLIERS OF INSTRUMENTATION & PROCESS CONTROL EQUIPMENTS
BUYER'S OF SILICON
APPENDIX – A:
01. PLANT ECONOMICS
02. LAND & BUILDING
03. PLANT AND MACHINERY
04. OTHER FIXED ASSESTS
05. FIXED CAPITAL
06. RAW MATERIAL
07. SALARY AND WAGES
08. UTILITIES AND OVERHEADS
09. TOTAL WORKING CAPITAL
10. TOTAL CAPITAL INVESTMENT
11. COST OF PRODUCTION
12. TURN OVER/ANNUM
13. BREAK EVEN POINT
14. RESOURCES FOR FINANCE
15. INSTALMENT PAYABLE IN 5 YEARS
16. DEPRECIATION CHART FOR 5 YEARS
17. PROFIT ANALYSIS FOR 5 YEARS
18. PROJECTED BALANCE SHEET FOR (5 YEARS)
