Glass membrane for controlled diffusion of gases

Details Glass membrane for controlled diffusion of gases Glass membrane for controlled diffusion of gases

1999-04-09

2001-05-15

Spitzer, Robert H. (Department: 1724)

Gas separation: processes

Selective diffusion of gases

Selective diffusion of gases through substantially solid...

C095S053000, C095S055000, C096S010000

Reexamination Certificate

active

06231642

ABSTRACT:

TECHNICAL FIELD
This invention relates to glass having controlled permeability. In particular, this invention relates to glass vessels and methods for storage and separation of gases.
BACKGROUND ART
Glass is almost infinitely selective in separations involving either hydrogen or helium. In addition, glass spheres have been proposed as a means for storing hydrogen. The extremely low permeability of hydrogen through glass at ambient temperatures provides a basis for using glass microspheres as a medium for hydrogen storage and separation devices. A disadvantage associated with these devices is that the glass has insufficient permeability for rapid release of the gas. This lack of permeability affects devices employing glass microspheres by requiring enormous surface areas for rapidly loading and unloading hydrogen.
Designers have attempted to solve this problem by using temperature to control the permeability of hydrogen or helium through the glass. These processes require temperatures in excess of 300° C. to increase the permeability of hydrogen or helium sufficiently for satisfying the requirements of commercial applications. Unfortunately, the costs associated with the energy and the energy management systems required to adjust permeability are unacceptable for commercial applications. In addition, the slow response or lag time associated with the temperature change does not lend itself to a market where users are accustomed to just turning a valve to receive products.
For example, Robert J. Teitel, in U.S. Pat. No. 4,302,217 “Hydrogen Supply System”, describes the use of glass microspheres to store hydrogen. Applying heat to the glass microspheres increases the permeability of the glass to release hydrogen from storage. The released hydrogen then serves as a clean-burning fuel for automobiles. Similarly, Hammel, et. al. in U.S. Pat. No. 4,842,620 “Process of Gas Enrichment with Porous Siliceous-Containing Material,” describe the use of hollow glass fibers having pore sizes ranging from 1 to 50 Angstroms in diameter as a device for performing gas separations. This device relies upon the one-way diffusion of gas through glass fibers to enrich gas streams.
As far as known, the low permeability of gases through glass has prevented glass spheres from achieving commercial acceptance for gas storage applications. Furthermore, the lag time associated with releasing hydrogen from glass microspheres prohibits their use for applications that demand an immediate supply of gas. Finally, gas separation applications require enormous lengths of fiber to separate commercial quantities of gas.
It is an object of the invention to provide a cost effective alternative to current commercial methods for storage and transport of gases such as hydrogen that rely on high pressure tanks or use of its liquid phase.
It is a further object of the invention to provide a low-cost selective membrane for separating gases.
SUMMARY OF THE INVENTION
A glass structure for controlled permeability of gases includes a glass vessel. The glass vessel has walls and a hollow center for receiving a gas. The glass vessel contains a metal oxide dopant formed with at least one metal selected from the group consisting of transition metals and rare earth metals for controlling diffusion of the gas through the walls of the glass vessel. The vessel releases the gas through its walls upon exposure to a radiation source.
The method controls permeability of gases in a vessel. The vessel includes a glass membrane having controlled diffusion. Providing a pressure drop across the glass membrane provides a driving force to send a gas through the glass membrane. The pressure drop consists of the glass membrane separating a high pressure region and a low pressure region within the vessel. Then irradiating the glass membrane accelerates diffusion of the gas through the glass membrane to the low pressure region.


REFERENCES:
patent: 2892508 (1959-06-01), Kohman et al.
patent: 3019853 (1962-02-01), Kohman et al.
patent: 3022858 (1962-02-01), Tillyer et al.
patent: 3135591 (1964-06-01), Jones
patent: 4302217 (1981-11-01), Teitel
patent: 4328768 (1982-05-01), Tracy et al.
patent: 4482360 (1984-11-01), Taketomo et al.
patent: 4842620 (1989-06-01), Hammel et al.
patent: 4853001 (1989-08-01), Hammel
patent: 4902307 (1990-02-01), Gavalas et al.
patent: 5326640 (1994-07-01), Japka
patent: 5342431 (1994-08-01), Anderson et al.
patent: 5344798 (1994-09-01), Morimoto et al.
patent: 5772735 (1998-06-01), Sehgal et al.
patent: 5830812 (1998-11-01), Shelestak et al.

Affiliated with

Also associated with

Rating

Glass membrane for controlled diffusion of gases does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Glass membrane for controlled diffusion of gases, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Glass membrane for controlled diffusion of gases will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2523607