HPVA II

High-Pressure Volumetric Analyzer

Pressure ranges from high vacuum to 100 or 200 bar
Broad temperature capability from cryogenic to 500°C
Fully automated analysis
MicroActive interactive software for data reduction

Overview

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

Four Methods of Sample Temperature Control

Refrigerated/heated recirculation vessel [customer provides temperature control bath]
Four-liter, stainless-steel dewar for liquid cryogen
Furnance allows for experiments ranging up to 500 °C
Cryostat can precisely control sample temperatures from ambient conditions to 30 K

System Schematic

Manifold

All the valves in the manifold are pneumatically operated, high-pressure valves with Kel-F® seats. Valve tubing is constructed with heavy wall, 316L stainless steel and is attached via a VCR connection or welded. The temperature of the insulated manifold region is stabilized using a heater controlled by an adjustable PID controller.

Pressure Transducers

Two transducers are used to precisely measure the system pressure. A 1000- torr transducer is used to accurately monitor pressures below 1 atmosphere and is protected from high pressure with an isolation valve and a cracking valve that relieves to the vent.

Servo Valves

The servo valves are used to automatically regulate flow of the gas in the manifold to the vent and vacuum.

Vacuum System

Consists of a mechanical pump and internal Pirani vacuum gauge. User can provide their own pump or purchase the high-vacuum turbo pump package.

Why HPVA II?

Benefits

Dual free-space measurement for accurate isotherm data
Free space can be measured or entered
Correction for non-ideality of analysis gas using NIST REFPROP compressibility factors calculated from multiple equations of state
Reports provided as interactive spreadsheets
Isotherm and weight percentage plots created automatically

Tables of raw data used for report calculations
Real-time charts for Pressure vs. Time and Temperature vs. Time
Gas mixtures with up to three components can be used
Kinetic data provided for rate of adsorpotion calculations
Langmuir equation used to model Type I isotherms

High-precision, solid-state design high-pressure transducer provides a reading accuracy of ±0.04% full scale with a stablility of ±0.1%
Low-pressure pressure transducer provides a reading accuracy of ±0.15% of value
System can attain a maximum pressure of 200 bar
Hydrogen gas sensor automatically shuts down the system should a hydrogen leak occur
BET surface area, Langmuir surface area, and total pore volume calculations included

Cryostat

For extensive hydrogen storage studies at high pressures and low temperatures, the HPVA II can be interfaced with a cryostat to control analysis temperatures down to 30 K with a stability of ±0.003 K. The cryostat does not require liquid cryogens for operation; instead, it utilizes the Gifford-McMahon refrigeration cycle where pressurized helium is supplied from a compressor to produce cold temperatures. The HPVA II software communicates directly with the cryostat temperature controller allowing for precise temperature measurements recorded over the duration of the adsorption experiment. Generating hydrogen adsorption isotherms at multiple cryogenic temperatures presents researchers the advantage of more accurately calculating the isosteric heats of adsorption of hydrogen on their materials of study.

Applications

Carbon Dioxide Sequestration

Evaluating the quantity of carbon dioxide that can be adsorbed by carbons...

Hydrogen Storage

Determining the hydrogen storage capacity of materials such as porous carbons and...

Coal-Bed Methane

Porous coal samples from underground beds can be analyzed with the HPVA...

Shale Gas

High-pressure methane can be dosed onto shale samples to generate adsorption and...

Capabilities

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)
Temperature	10 to 45℃ (50 to 113oF), operating -10 to 55℃ (14 to 131oF), non operating

Electrical

Voltage	100 – 240 VAC
Frequency	50 to 60 Hz

Provided specifications were valid as taken from available documents at time of publication. These specifications may change without notice and are only provided as a general reference

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HPVA II P02

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