Measuring and testing – Testing of material
Reexamination Certificate
2001-04-04
2004-01-27
Noland, Thomas P. (Department: 2856)
Measuring and testing
Testing of material
C055S342000, C055S342100, C055S344000, C095S025000, C095S043000, C096S007000, C096S417000, C073S038000
Reexamination Certificate
active
06681648
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to separation membranes, more particularly to gas separation membranes, and especially to meniscus-shaped membranes for gas separations as well as the use of such meniscus-shaped membranes for applications such as thermal gas valves, pre-concentration of a gas stream, and selective pre-screening of a gas stream.
BACKGROUND OF THE INVENTION
The last decade has seen a dramatic increase in the use of polymer membranes as an effective, economical and flexible tool for many gas separations. The processability, gas solubility, and selectivity of several classes of polymers (such as polyimides, polysulfones, polyesters and the like) have led to their use in a number of successful gas separation applications. A drawback to the use of polymer membranes for gas separation can be their low permeability. In most instances, the success of a given membrane rests on achieving adequate fluxes.
The commercial use of polymer membranes for air separation, the recovery of hydrogen from mixtures of nitrogen, carbon monoxide and methane, and the removal of carbon dioxide from natural gas has been reported. In each of these applications, high fluxes and excellent selectivities have relied upon glassy polymer membranes which rely on gas size differences for separation of species. Yet, this technology has focused on optimizing separation materials for near ambient conditions. The development of polymeric materials that achieve good combinations of high selectivity, high permeability, mechanical stability and processability at temperatures above about 25° C. and pressures above about 10 bar has been needed.
Separation of carbon dioxide (CO
2
) from mixed gas streams is of major industrial interest. Continued improvements in such separations are sought. Commercially viable membrane-based approaches to industrial CO
2
separations require reduction in costly drops in operating temperatures and pressures while maintaining high fluxes. The need for higher flux CO
2
separation approaches remains.
Other research efforts have been directed to the development of polymer membranes that operate at elevated temperatures and pressures.
Through the efforts of the present inventors, a polymer membrane design has now been achieved which can operate under high fluxes. Such a polymer membrane design involves a meniscus-shaped polymer membrane within one or more small pore or opening. That polymer membrane design allows for a number of varying applications described herein.
It is an object of this invention to provide a polymer membrane capable of operation under high fluxes.
It is another object of this invention to provide a meniscus-shaped polymer membrane within one or more small pore or opening, the meniscus-shaped polymer membrane contained substantially completely within such small pores or openings.
Still another object of the present invention is a process for rapidly screening polymers for membranes in non-ambient gas separations by use of such a meniscus-shaped polymer membrane.
Still another object of the present invention is the use of a meniscus-shaped polymer membrane as a selective pre-screen, e.g., for a sensor system including a sensor element where the meniscus-shaped polymer membrane can serve to screen out molecules that would contaminate the sensor element.
Still another object of the present invention is the use of a meniscus-shaped polymer as a pressure/temperature sensor element.
Still another object of the present invention is the use of a meniscus-shaped polymer as a pre-concentrator for a gas stream prior to entry into, e.g., a mass spectrometer.
Still another object of the present invention is the use of a meniscus-shaped polymer as a temperature controlled valve in a gas separation system.
SUMMARY OF THE INVENTION
To achieve the foregoing and other objects, and in accordance with the purposes of the present invention, as embodied and broadly described herein, provides a process for simultaneously screening a multiplicity of polymer materials for comparative effectiveness in gas separation, the process including preparing an array of individual testing ports on a substrate, each individual port including a pore passing through said substrate, a gas inlet to said pore at a first location of said substrate and a gas outlet from said pore at a second location of said substrate, placing said multiplicity of polymer materials, each within a pore of at least one individual port in an amount sufficient to form a meniscus-shaped polymer membrane within said pore, passing a pre-selected gas flow to said gas inlet, analyzing gas flow from said gas outlet, and, comparing gas separation properties for said multiplicity of polymer materials.
The present invention further provides a screening system for simultaneously screening polymer materials for effectiveness in gas separation including a substrate containing an array of individual ports, each port including a pore passing through said substrate, a gas inlet to said pore at a first location of said substrate and a gas outlet from said pore at a second location of said substrate, a meniscus-shaped polymer membrane situated within said pore with each meniscus-shaped polymer membrane formed of a pre-selected polymer material, and, a gas analyzer controllable attached to said outlet gas flows.
The present invention further provides the improvement in a gas separation process using a solid polymer membrane as a gas separator, wherein said solid polymer membrane is selected through the above-described screening process.
The present invention further provides a gas separation module including a substrate containing at least one opening therein, and, a polymer material contained within the opening of said substrate, said polymer material characterized as forming a meniscus-shaped separator within said opening.
The present invention further provides a temperature gas valve including a gas separation module including a substrate containing at least one opening therein and a polymer material contained within the opening of said substrate, said polymer material characterized as forming a meniscus-shaped separator within said opening, said temperature gas valve characterized as preventing a pre-selected gas to pass through said polymer material at a first temperature, but allowing said pre-selected gas to pass through said polymer material at a second temperature.
The present invention further provides an improvement in a detector including a sensing element responsive to the presence of a pre-selected species, said sensing element characterized as subject to deactivation in the presence of selected volatile organic materials, the improvement being location of a polymer membrane between said sensing element and any ambient atmosphere, said polymer membrane capable of allowing said pre-selected species to pass therethrough to said sensing element and said polymer membrane capable of preventing sufficient selected volatile organic materials to pass therethrough to said sensing element whereby said sensing element is deactivated.
REFERENCES:
patent: 3350844 (1967-11-01), Robb
patent: 3781979 (1974-01-01), Stone
patent: 3993462 (1976-11-01), Jones
patent: 5064446 (1991-11-01), Kusuki et al.
patent: 6175409 (2001-01-01), Nielsen et al.
patent: 6210464 (2001-04-01), Nakanishi et al.
patent: 6355420 (2002-03-01), Chan
patent: 63-116726 (1988-05-01), None
patent: 2001-29761 (2001-02-01), None
Dye Robert C.
Jorgensen Betty
Pesiri David R.
Cottrell Bruce H.
Noland Thomas P.
The Regents of the University of California
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