The HPVA II obtains high-pressure adsorption and desorption isotherms using gases, including carbon dioxide, methane, and hydrogen, by using the static volumetric approach.
- High vacuum to 100 or 200 bar of pressure
- Wide temperature range: 500 °C to cryogenic
- Completely automatic evaluation
- MicroActive interactive data reduction software
Description
Only a few milligrams of samples are needed to analyze a wide range of materials, such as MOFs, zeolites, and microporous carbons. Users can better understand applications like batteries and fuel cells, carbon dioxide sequestration, hydrogen storage, and hydrocarbon traps.
Features and Benefits
- One port or four sample ports can be analyzed concurrently
- Common adsorbates include carbon dioxide, oxygen, nitrogen, hydrogen, methane, and argon.
- Software includes NIST REFPROP.
- Sample temperature can be precisely controlled using a cryostat, furnace, cryogen dewar, or recirculating bath.
- Temperature management of the manifold using a heater for accuracy and stability
HPVA II. Image Credit: Micromeritics Instrument Corporation
HPVA II 4-Port. Image Credit: Micromeritics Instrument Corporation
Specification
Source: Micromeritics Instrument Corporation
| Physical |
| Height |
88.9 cm (35 in.) |
| Width |
50.8 cm (20 in.) |
| Depth |
50.8 cm (20 in.) |
| Weight |
27.2 kg(60 lbs) |
| Electrical |
| Voltage |
100 – 240 VAC |
| Frequency |
50 to 60 Hz |
| Physical |
| Temperature |
10 to 45 °C (50 to 113 °F), operating
-10 to 55 °C (14 to 131 °F), non operating |
Technology
Manifold
The manifold contains only high-pressure pneumatically controlled valves. Heavy wall 316 L stainless steel is used for all valve connections, which can be welded or connected via VCR or VCO connections. Two-micron in-line filters are installed on all gas lines. A 10-9 cm3 atm/sec leak test is performed on the manifold.
Pressure Transducer
Depending on the unit's maximum operating pressure, the transducer is either an electronic Bourdon gauge (Mensor) or a capacitance manometer (MKS Baratron). VCR connectors are used to make connections in both situations.
Vacuum System
Consists of a Pirani vacuum gauge and a 5-CFM mechanical pump. Pump with molecular drag or turbo available.
Constant Temperature Bath
The chilled circulating bath (supplied) maintains a consistent temperature for the chosen sample.
Activation Unit
The HPVA analyzer for multiport units comes with a separate activation unit for drying or activating the samples before testing; this device is made up of a manifold, a furnace, and a vacuum system with a manifold-to-vacuum system pneumatic valve that has a one-inch diameter.
Sample holders are fastened to the analysis manifold using VCO connectors. A helium line is supplied for backfilling. The furnace, managed by a PID routine with ramp and soak capabilities, can reach temperatures up to 500 °C.
HPVA II Features
- High Vacuum to 100 or 200 bar, a wide operating pressure range
- Broad Temperature Range: 500 °C to cryogenic
- Superior temperature control of the sample using a furnace, cryogen dewar, or recirculating temperature bath
- Temperature management of the manifold using a heater for accuracy and stability
- Analysis that is entirely automated and uses interactive software
- Outstanding repeatability of the data
- Handles common adsorbates like carbon dioxide, oxygen, hydrogen, methane, argon, and nitrogen
- All-inclusive data analysis package with NIST REFPROP software and Microsoft Excel macros for data processing and charting
Image Credit: Micromeritics Instrument Corporation
Application
Typical HPVA II Applications
Carbon Dioxide Sequestration
In the current research on carbon dioxide sequestration, determining how much carbon dioxide may be absorbed by carbons and other materials is crucial. Sites where CO2 is to be injected can be simulated underground using high pressures obtained with the HPVA II.
The user can assess CO2 uptake at various stable temperatures by configuring the HPVA II with a chiller/heater bath. This data can be utilized to compute the heat of adsorption. Because CO2 condensation occurs at greater pressures, these isotherms are usually examined up to around 50 bar at temperatures close to ambient conditions.
Hydrogen Storage
In the current quest for sustainable energy sources, figuring out a material's ability to store hydrogens, such as porous carbons and metal-organic frameworks (MOFs), is essential. These materials let the user securely absorb and desorb hydrogen, making them perfect for storage.
Compared to gaseous hydrogen, stored adsorbed hydrogen in MOFs has a higher energy density per volume and does not require freezing temperatures to keep hydrogen in a liquid state. The HPVA II software offers a weight percentage plot, the industry standard for examining a sample's hydrogen storage capacity.
Coal-Bed Methane
The HPVA II examines porous coal samples from subterranean beds to ascertain their methane capacity at high pressures. Estimating the amounts of hydrocarbons available in coal-bed reserves enables the user to calculate the underground coal beds' methane adsorption and desorption properties.
The rate of methane adsorption and desorption on these porous carbon samples at particular pressures and temperatures can also be determined from the kinetic data obtained from the tests.
Shale Gas
Shale samples can be dosed with high-pressure methane to produce isotherms for adsorption and desorption. This gives the shale's methane capacity at various temperatures and pressures. The adsorption isotherm can determine the shale's volume and Langmuir surface area.
The surface area of the shale, where the adsorbate gas forms a single layer of molecules, is known as the Langmuir surface area. The largest amount of methane that can be adsorbed to the sample's surface is the Langmuir volume, which is the absorption of methane at infinite pressure.