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High Pressure Gas Adsorption for Gas Storage Material

iSorb HP1 | HP2: High Pressure gas sorption analyzer

High Pressure Gas Adsorption for
Gas Storage Materials Characterization

High pressure adsorption measurements are important in the fields of carbon dioxide sequestration, methane storage, hydrogen storage, and gas separation. The iSorb-HP instruments (volumetric sorption or Sieverts apparatus) generate automatic measurements of full adsorption and desorption isotherms over a wide range of pressures and temperatures. These isotherms can be displayed in the traditional surface excess vs. pressure plot or as a PCT (Pressure-Composition-Temperature) plot. See more .

The iSorb series is a family of four such high pressure sorption instruments; one and two-sample models each available with an upper pressure limit of 100bar or 200bar, complete with built in vacuum pumps and sample degassing capability. All models feature pressure transducers both in the dosing manifold and on the sample cell for maximum sensitivity; this also provides the iSorb-HP2 model the capability to simultaneously analyze two samples.

High pressuregas sorption measurements are defined in terms of pressure or dose amount for both adsorption and desorption, equilibrium criteria, sample temperature (according to the heating /cooling device selected) and choice of equation of state (EoS)*:

High pressure gas sorption analyzer, the iSorb HP
  • Schmidt-Wenzel type, defined in terms of Helmholtz free energy (NIST recommended)
  • MBWR (Modified Benedict-Webb-Rubin type, Jacobsen 32-coefficients, NIST recommended).
  • Lee-Kesler (generalized Benedict-Webb-Rubin).
  • Peng-Robinson
  • Soave-Redlich-Kwong
  • Redlich-Kwong
  • Van der Waals
  • Ideal gas

Analysis temperatures are achieved either by recirculator bath (-20oC to 100oC, see below), cryocooler (77K-320K), or heating mantle (up to 500oC).

Using the correct equation of state (EOS) is essential.This excess adsorption isotherm goes through a maximum. Click to enlarge



Gas pressure booster increases cylinder pressure from 55bar to 200bar.

This compensates for the drop in pressure from a standard laboratory cylinder as gas is used for analyses and ensures a constant supply of high pressure gas.


Isotherms can be measured from -20 to +100C with this recirculator.

This liquid chiller/heater
/circulator provides stable
sample temperatures from -20oC up to 100oC set via PC. Includes jacketed cell.



Cryogen-free sample
thermostating option for the
iSorbHP. The Cryo-Cooler allows gas sorption studies to be run at temperatures between 77K to