Properties of Borosilicate Glass
Borosilicate glass is widely used for laboratory glassware, wither mass produced or as custom made. Borosilicate glass has excellent thermal properties with its low coefficient of expansion and high softening point, it also offers a high level of resistance to attack from water, acids, salt solutions, organic solvents and halogens. Resistance to alkaline solutions are moderate and strong alkaline solutions cause rapid corrosion of the glass, as does hydrofluoric acid and hot concentrated phosphoric acid.
Pressure
Whilst it is possible to pressurize glassware, extreme care should be taken if your application requires pressurizing.
| Chemical Composition | |
| Silicon Dioxide | SiO2 = 80.6% |
| Boron Trioxide | B2O3 = 13.0% |
| Sodium Oxide | Na2O = 4.0% |
| Aluminum Oxide ( Alumina) | Al2O3 = 2.3% |
| Optical Information |
| Refractive Index (Sodium D Line) = 1.474 |
| Visible Light Transmission, 2mm Thickness = 92% |
| Visible Light Transmission, 5mm Thickness = 91% |
| Physical Properties |
| Coefficient of Expansion (20-300oC) 3.3 x 10-6K-1 |
| Density 2.23g/cm3 |
| Dielectric Constant (1MHz, 20oC) 4.6 |
| Specific Heat (20oC) 750J/kgoC |
| Thermal Conductivity (20oC) 1.14W/moC |
| Poisson’s Ration (25-400oC) 0.2 |
| Young’s Modulus (25oC) 6400kg/mm2 |
Critical Temperatures
150oC – When working above this temperature care should be taken to heat and cool borosilicate glass in a slow and uniform manner.
500oC – The maximum temperature that Borosilicate glass should be subjected to and then only for short period of no longer than a few minutes.
510oC – Temperature at which thermal stress can be introduced to Borosilicate glassware.
565oC – Annealing temperature. When uniformly heated in controlled conditions, such as a kiln or oven thermal stress’s can be removed.
820oC – Softening point at which Borosilicate may deform.
1252oC – Melting point, the temperature that glassblowers need to attain in order to work Borosilicate glass.
PTFE
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluororthylene that finds numerous applications. The most well known brand name of PTFE is Teflon by DuPont Co.
PTFE is a fluorocarbon solid, as it is a high- molecular-weight compound consisting wholly of carbon and fluorine. PTFE is hydrophobic: neither water nor water-containing substances wet PTFE, as fluorocarbons demonstrate mitigated London dispersion forces due to the high electronegativity of fluorine. PTFE has one of the lowest coefficients of friction against any solid.
PTFE is used as a non-stick coating. It is very non-reactive, partly because of the strength of carbon-fluorine bonds, and so it is often used in containers and pipe work for reactive and corrosive chemicals. Where used as a lubricant, PTFE reduces friction, wear, and energy consumption of machinery.
It is commonly believed that Teflon, like velcro, is a spin-off product from the NASA space projects. However, that is not so, even though both products have been used by NASA.
Formation
It is formed by the polymerization of tetrafluoroethylene:
nF2C=CF2→ —{ F2C—CF2}—
Properties
Property Value Density 2200 kg/m3
Melting point 327 °C
Thermal expansion 135 · 10−6 K−1 [10]
Thermal diffusivity 0.124 mm²/s [11]
Young’s modulus 0.5 GPa
Yield strength 23 MPa
Bulk resistivity 1018 Ω·cm [12]
Coefficient of friction 0.05–0.10
Dielectric constant ε=2.1,tan(δ)<5(-4)
Dielectric constant (60 Hz) ε=2.1,tan(δ)<2(-4)
Dielectric strength (1 MHz) 60 MV/m
Safety
The pyrolysis of PTFE is detectable at 200 °C (392 °F), and it evolves several fluorocarbon gases and a sublimate. Animal studies indicate that it is unlikely that these products would be generated in amounts significant to health at temperatures below 250 °C (482 °F), although birds are proven to be much more sensitive to these decomposition products.
While PTFE is stable and nontoxic, it begins to deteriorate after the temperature reaches about 260 °C (500 °F), and decomposes above 350 °C (662 °F). These degradation by-products can be lethal to birds, and can cause flu-like symptoms in humans.
Stainless Steel 304
Type 304 stainless steel is a T 300 Series Stainless Steel austenitic. It has a minimum of 18% chromium and 8% nickel, combined with a maximum of 0.08% carbon. It is defined as a Chromium-Nickel austenitic alloy.
Grade 304 is the standard “18/8” stainless that you will probably see in your pans and cookery tools.
These are some of its characteristics:
– Forming and welding properties
– Corrosion/ oxidation resistance thanks to the chromium content
– Deep drawing quality
– Excellent toughness, even down to cryonegic temperatures which are defined as very low temperatures
– Low temperature properties responding well to hardening by cold working
– Ease of cleaning, ease of fabrication, beauty of appearance
Component Wt. %
C Max 0.08
Cr 18 – 20
Fe 66.345 – 74
Mn Max 2
Ni 8 – 10.5
P Max 0.045
S Max 0.03
Si Max 1
Properties
Properties Value Comment Physical Properties
Density 8.03 g/cc
Mechanical properties
Hardness, Rockwell B 82 Tensile Strength,
Ultimate 621 Mpa (=90100psi)
Tensile Strength, Yield 290 Mpa (=42100psi) 0.2%
YS Elongation at Break 55% in 2 inches
Modulus of Elasticity 193 Gpa tension
Modulus of Elasticity 78 Gpa torsion
Electrical properties
Electrical Resistivity 0.000116 ohm-cm 659 °C
Electrical Resistivity 7.2e-005 ohm-cm
Magenetic permeability Max 1.02 H = 200 Oersteds,
Annealed Thermal properties
CTE, linear 20°C 16.9 µm/m-°C 0 to 100°C
CTE, linear 20°C 18.7 µm/m-°C to 649°C
Heat Capacity 0.5 J/g-°C 0°C to 100°
Thermal Conductivity 16.2 W/m-K 100°C
Thermal Conductivity 21.4 W/m-K 500°C
Processing properties
Melt temperature 1371- 1399°C
Applications
It is used for a wide variety of home and commercial applications, this is one of the most familiar and most frequently used alloys in the stainless steel family.
Food processing equipment, particularly in beer brewing, milk processing & wine making.
For example it is highly suitable and applied in dairy equipment such as milking machines, containers, homogenizers, sterilizers, and storage and hauling tanks, including piping, valves, milk trucks and railroad cars.
Because of its ability to withstand the corrosive action of various acids found in fruits, meats, milk, and vegetables, Type 304 is used for sinks, tabletops, coffee urns, stoves, refrigerators, milk and cream dispensers, and steam tables. It is also used in numerous other utensils such as cooking appliances, pots, pans, and flatware.
– Architectural panelling, railings & trim
– Chemical containers, including for transport
– Heat Exchangers
– Woven or welded screens for mining, quarrying & water filtration
– Dyeing industry
– In the marine environment, because of it slightly higher strength and wear resistance than type 316 it is also used for nuts, bolts, screws, and other fasteners.
Advantages of Glass Construction
While the all glass design lacks the strength provided by external steel construction, the borosilicate glass 3.3 reactors provide the same superior corrosion resistance as our glass-lined vessels with the additional benefit of process visibility. This feature makes the SG Labware glass reactors series a popular choice in research and development.
Product Description
The SG Labware glass reactor series are made of borosilicate glass, which combines process visibility, purity, corrosion resistance, and long term service. Complemented by other highly corrosion resistant materials such as PTFE, PEEK & stainless steel 304/316, the SG Labware glass reactor series can handle a variety of applications.
Applications
The SG Labware glass reactor is widely used in research and development as well as kilo plant production applications throughout the chemical, biotech, and pharmaceutical industries.
Volume of Reactors (Working Capacity)
Bio Glass Reactors 75ml-3L, Bench Top
Standard Glass Reactors 5L-30L, Floor Stand
Large Glass Reactors 50L-200L, Floor Stand
Shape of Vessel
Round Bottom Only
– Allow uniform heating/cooling of liquid
– More heating/cooling surface contents
– More resistant to fracturing under vacuum
– More evenly distributes stress across its surface
Layers of Vessel
Single Layer Vessel
– No heating/cooling require
– Mixing in room temperature
– Header tanks, maintains a gravity feed or a static fluid pressure in vessel
Double Layer Vessel
– Thermal jacket, for heating/cooling
– Temperature -80oC to +250oC
Triple Layer Vessel
– Vacuum layer
– Provide constant temperature
Choosing a Right Vessel
– Working Capacity
– Working Temperature (double/triple layer)
Choosing a Right Lid
– Number of necks request
– Solid/Liquid/Gas feeds
Choosing a Right Over Head Stirrer Motor
The stirrer shafts are fitted into the motor chucks and the chucks are tightened with a key wrench. A complete stirrer comprises a stirrer motor and a shaft with a stirrer blade.
– Japan AC induction motor
– No dynamo brush and spark-free
– Continuously viable agitator speed
– Single phase 220V 50Hz
– Motor power 40/60/120/180/250W-
– Rotation speed 0-600/800rpm
– Torque 30,44,162,210,300,400Ncm
Choosing a Right Propeller
– Stainless steel/Stainless steel with PTFE coated
– 1/2/3 stage propeller
– Anchor/Pitched Blade/Retreat Curve impeller
Choosing a Right Discharge Valve
– Stainless steel, PTFE or glass-lined valve (GMP)
– Product flow
– Location of the valve
Choosing a Right Accessories
– Condenser, flow rate/length/double coils/reflux
– Dropping funnel/ pressure equalizing dropping funnel
– Collecting Flask/volume
– Glass adaptors
– Diaphragm pump
– Circulators
Baffles
Baffles are one of the most important components in mixing. The installation of baffles in a vessel aid in breaking the rotation of the liquid and eliminate the formation of the vortex caused by high impeller speeds. The use of baffles overcomes the additional problem of air entrapment, resulting in better top-to-bottom circulation.
Use of Baffles
The main roles of a baffle in a vessel
– Prevent the effects of vibration, which is increased with both fluid velocity and the length of the exchanger.
– Direct shell-side fluid flow along vessel field. This increase fluid velocity and the effective heat transfer co-efficient of the exchanger.
In a chemical reactor, baffles are often attached to the interior walls to promote mixing and thus increase heat transfer and possibly chemical reaction rates.
Types of Baffles
Implementation of baffles is decided on the basis of size, cost and their ability to lend support to the vessel and direct flow. Often this is linked to available pressure drop and the size and number of passes within the exchanger. Special allowances/changes also made for finned vessels. The different types of baffles include :
– Segmentalbaffles
– Helical baffles
– Longitudinal flow baffles
– Impingement baffles
– Orifice baffles
– Rod/bar baffles (giving a uniform shell-side flow)
Distillation and Extraction
The thermal separation techniques of distillation and extraction are required in the chemical process industry to produce an intermediate or final product. These processes are employed to separate liquids from liquids as well as liquids from solids. From individual components to complete separation systems, De Dietrich Process Systems has the necessary equipment and knowledge to assist you with your separation needs.
Distillation is the operation whereby the vaporization of a liquid mixture yields a vapor phase containing more than one component, and it is desired to recover one or more of these components in a pure state. Distillation as such is a major unit operation in the chemical processing industry for the purification or separation of liquid mixtures. Distillation in practical operations can be effected on either a continuous or a batch mode of operation. Columns which are packed or fitted with trays provide several theoretical stages of separation. De Dietrich Process Systems offers a complete range of equipment and systems suitable for rigorous distillation processes.
Glass Column Product Description
Borosilicate glass columns have been used successfully for many years in the field of distillation operations mainly for the benefits of its anti-corrosive and transparent material of construction.
Glass Column Features
Glass distillation columns are normally filled with packing materials made of borosilicate glass, but other packing materials can also be supplied. Cooling arrangements for the distillate can use either shell and tube or coil type heat exchangers.
Options
- Durapack – a structured glass packing with outstanding separation properties, ideal for processes that require no metal.
- Core-Tray support – provides a solution for the problem of metal-free support trays with a large free cross-section of 120%.
- Liquid feeds based on the same Core-Tray design principle are also available.
- Liquid collectors
- Redistributors
- Automatic control system
- Reboiler vessels
- Condensers
- Boilers
- Coolers
- Reflux separators and timers
- Packing
Basic glass pilot reactor and pilot plant
Typical applications
- Vacuum distillation
- Azeotropic distillation (phase separation)
- Evaporation to any desired consistency
- Multi-component reactions
- Gas introduction into liquid phase
- Extraction of multi phase mixture
- Crystallization
- Refluxing
- Multiple chemical reactions liquid/liquid, liquid/solid
- Low temperature chemistry
Glass Reactors / Mixing vessel
Typical applications
- Work-up
- Conditioning
- Dissolving
- Extraction
- Mixing, stirring
- Phase separation
Nutsch filters
Typical applications
- Filtration
- Drying
- Crystallization
- Ion exchange
- Solid phase synthesis
- Chromatography