HPVA II

The HPVA II uses the static volumetric method to obtain high pressure adsorption and desorption isotherms utilizing gases such as hydrogen, methane, and carbon dioxide. Analyze a variety of materials including MOFs, zeolites and microporous carbons using just a few milligrams of sample. Obtain a better understanding of applications such as hydrogen storage, carbon dioxide sequestration, fuel cells and batteries, and hydrocarbon traps.

 

Features and Benefits:

• Single port, or four sample ports with simultaneous analysis
•  Typical adsorbates such as nitrogen, hydrogen, methane, argon, oxygen, and carbon dioxide
•  Software includes NIST REFPROP
•  Excellent control of sample temperature using a recirculating bath, cryogen dewar, cryostat or furnace
•  Manifold temperature controlled with heater for stability and accuracy

Specifications

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℃ (50 to 113oF), operating -10 to 55℃ (14 to 131oF), non operating

Technology

 

 

Manifold

All the valves in the manifold are pneumatically operated high-pressure valves. All valve connections are made with heavy wall 316L stainless-steel, and are either welded or use VCR or VCO connections. All gas lines are fitted with 2 micron in-line filters. The manifold is leak-tested to 10^-9 cm³ atm/sec.

 

Pressure Transducer

Depending on the maximum operational pressure of the unit, the transducer is either a capacitance manometer-type (MKS Baratron) or an electronic Bourdon gauge-type (Mensor). In both cases, connections are made via VCR connectors.

 

Vacuum System

Consists of a 5-CFM mechanical pump and Pirani vacuum gauge. Turbo or Molecular Drag pump optional.

 

Constant Temperature Bath

The operator-selected sample temperature is maintained constant by the refrigerated circulation bath (provided).

 

Activation Unit

For multiport units, the HPVA analyzer includes a separate activation unit for drying or activating the samples before testing, this unit consists of a vacuum system, a furnace and a manifold with a one inch diameter pneumatic valve connecting the vacuum system to the manifold. VCO connectors are used to attach the sample holders to the analysis manifold. A helium line is also provided for back filling. The furnace is capable of temperatures up to 500°C, controlled with a PID routine which includes ramp and soak capabilities.

 

HPVA II Features

• Wide Operating Pressure range: High Vacuum to 100 or 200 bar
• Broad Temperature Capability: From cryogenic to 500 °C
• Excellent control of sample temperature by means of a recirculating temperature bath, cryogen dewar, or furnace
• Manifold temperature controlled with heater for stability and accuracy
• Fully automated analysis using interactive software
• Excellent data reproducibility
• Handles typical adsorbates such as nitrogen, hydrogen, methane, argon, oxygen, and carbon dioxide
• Comprehensive Data Analysis package using Microsoft® Excel® macros for data processing and graphing
• Software includes NIST REFPROP

Typical HPVA II Applications

Carbon Dioxide Sequestration

Evaluating the quantity of carbon dioxide that can be adsorbed by carbons and other materials is important in the ongoing study of carbon dioxide sequestration. High pressures obtained with the HPVA II can simulate the underground conditions of sites where CO2 is to be injected. Configuring the HPVA II with a chiller/heater bath allows the user to evaluate the CO2 uptake at a range of stable temperatures, providing data that can be used to calculate heats of adsorption. These isotherms are typically analyzed up to approximately 50 bar at near ambient temperatures due to CO2 condensation at higher pressures.

 

Hydrogen Storage

Determining the hydrogen storage capacity of materials such as porous carbons and metal organic frameworks (MOFs) is pivotal in the modern demand for clean energy sources. These materials are ideally suited for storage because they allow you to safely adsorb and desorb the hydrogen. Stored adsorbed hydrogen in MOFs has a higher energy density by volume than a gaseous hydrogen and does not require the cryogenic temperatures needed to maintain hydrogen in a liquid state. The HPVA II software provides a weight percentage plot that illustrates the amount of gas adsorbed at a given pressure as a function of the sample mass − the standard method for reviewing a sample’s hydrogen storage capacity.

 

Coal-Bed Methane

Porous coal samples from underground beds can be analyzed with the HPVA II to determine their methane capacity at high pressures. This allows the user to find the methane adsorption and desorption properities of the underground coal beds, which is useful in determining approximate amounts of hydrocarbons available in coal-bed reserves. Kinetic data from the experiments can also show the rate of metane adsorption and desorption on these porous carbon samples at specific pressures and temperatures.

 

Shale Gas

High-pressure methane can be dosed onto shale samples to generate adsorption and desorption isotherms. This provides the methane capacity of the shale at specific pressures and temperatures. The adsorption isotherm can be used to calculate the Langmuir surface area and volume of the shale. The Langmuir surface area is the surface area of the shale assuming that the adsorbate gas forms a single layer of molecules. The Langmuir volume is the uptake of methane at infinite pressure − the maximum possible volume of methane that can be adsorbed to the surface of the sample.

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