Biosilica from BiomassConstruction Material and Energy
ChK Group, Inc. Plano, Texas
ACS National Meeting & ExpositionDallas, TX
March 20, 2014
Rajan K. Vempati, Ph.D.
Prasad Rangaraju, Ph.D.
Antonio Nanni Ph.D.
Sridhar Komernini, Ph.D.
John Imhoff
Subbaraman Viswanathan, Ph.D.
Project Goals
Manufacture Amorphous silica from biomass (Biosilica) with multiple uses Construction material in High Strength Concrete Additive in paints, plastics & tires Zeolite manufacture
Sustainable Product Unlike Other Food Products used in Bio-Fuels. The Rice
Production for Human Consumption Unaffected. Generate Revenues
From Biosilica - a high value product Sell energy as steam and power
Create Jobs
Supply of Rice HullsAgricultural Waste Generated from Rice MillsUsed as fuel for its caloric value. Ash (black ash) with high carbon content is rejected as waste.Off-white or white Biolica Supply Potential is high
Major competition – from silica fumes in Cement
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AreaRice Mill Capacity Supply Biosilica
Competition From Silica Fumes (*)
USA 10.5 Million Tons 0.4 Million Tons 60,000 Tons
Worldwide 550 Million Tons 20 Million Tons --
Annual Capacities
(*) Silica fumes is a byproduct with limited capacity
Biosilica Premium Additive in High Performance Concrete (HPC)
Value Chain for Biosilica
Rice Cultivation and Processing in Rice Mills
ChK Process Biosilica Production and Power Generation
Biosilica to HPC and Power to the Grid
Currently Rice Hull is sent to landfills at a cost
Black ash is not suited for HPC due to high carbon content
ChK Process unique features:
• Biosilica Carbon content < 0.1%; NO graphitic carbon
• Zero crystallinity
• Produces process heat and power based on site requirements
• No solid waste as inorganic matter in rice hull becomes Biosilica
• Simple process easy to operate and control
• Zero CARBON emissions and future carbon CREDITS
Zero Carbon - Feed BIOMASS
Rice Hull Biosilica Plant
O2CO2
Photosynthesis
Rice Fields
Rice Milling PlantsGenerates Rice Hulls
Rice Hulls
Biosilica
CO2
O2
Atmosphere
Steam & Power
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Rice Hull Properties
HHV Dry Basis 16.2 MJ/KG[6,965 BTU/LB]
Moisture, W% 9.7%
Volatile, W% 66%
Carbon, W% MF 40.2%
Ash, W% 18.2%
Ash Composition (%) SiO2 95.00Al2O3 0.41Fe2O3 0.25CaO 0.75MgO 0.43K2O 2.20
Biosilica Properties• Silica content: > 90 W%• Type: Amorphous silica• Carbon Wt%: < 0.1 W%• Cristobalite: No crystalline matter
(verified in XRD and FTIR)• Major Uses:– Pozzolan additive to concrete; replaces 10 to 20% of
cement
– Produces ZSM-5 zeolite by thermochemical methods WITHOUT an organic template
– Filler in paints, plastics and tires
High Performance Concrete (HPC)Use to Mitigate Severe Erosion in Dams
Kinzua Dam in Pennsylvania HPC used to mitigate severe erosion due to abrasion with water flow
DOING WELL AFTER HPC INSTALLATION IN 1983
Addition of Biosilica in HPC Results in Slower Curing and Higher Strengths (Increase by 35%)
0
10
20
30
40
50
60
70
80
0 20 40 60 80 100Period of curing (days)
Com
pres
sive
stre
ngth
(MPa
)
Control
GRHA-7.5%
GRHA-15%
Figure – Rate of Development of Compressive Strength in GBiosilica Concrete
Figure – Comparison of the 28-Day Compressive Strength of UBiosilica and GBiosilica Concrete
Bridges in FloridaCorrosion concerns – State Government Specifies Addition of 8 to 9%
Silica Fume in Concrete that Stands in Salt Water or Gets Splashed
Bridge in Florida in US – 1 Highway
Other applications for Biosilica in HPC• Parking lots in cold climates – subjected to severe chloride corrosion from
salted roadways• High rise buildings that require HPC with high modulus of elasticity
Biosilica Substantially Reduces Chloride Permeability
Figure – Comparison of Chloride Permeability Values of Biosilica Concretes after 56-Day Curing
• Corrosion – Most Prominent Problem
• Alkali-Silica Reactivity (ASR)
• Delayed Ettringite Formation (DEF)
• Sulfate Attack
• Freeze-Thaw Damage
Durability Issues
Biosilica Use in ZSM-5 Production
• ChK Process - patented
– ChK has developed a process to minimize heating requirements without using any organic template
• Synthesis conditions
– Si/Al molar ratio of reaction mixture: 20 to 100
– Temperature 190°C (could use 200 LB steam for heat up)
– Crystallization time 36 hours
– Seeding with up to 1% ZSM 5
– Product is filtered washed and dried at 120°C.
– For special applications, ZSM-5 could be calcined, as needed
• Product ZSM-5 properties
– Si/Al Molar ratios of 80 and above are easily obtained.
– Carbon content of Rice Hull ash affects the type and quality of ZSM-5
Pilot Scale Rotary Calciner for BioSilica Manufacture
6 in diameter tube 20 FT long 3-Zone temperature
control
Large (Commercial Scale) Rotary Calciner (Illustrative)
6 FT diameter tube
> 60 FT longHeat input with a string of natural gas burners