Showing papers on "Gas separation published in 1989"
01 Jan 1989
TL;DR: In this article, a two-patch heterogeneous model with surface phase transition for benzene adsorption on silicalite is presented, where the authors use stochastic pore networks to model the correlation of equilibrium data.
Abstract: I. Characterization of Adsorbents and Tthermodynamics of Adsorption.- Characterization of adsorbents.- Theories of adsorption in micropores.- The statistical thermodynamic approach to the correlation of equilibrium data.- A two-patch heterogeneous model with surface phase transition for benzene adsorption on silicalite.- Interpretation of low temperature gas adsorption and desorption using stochastic pore networks.- Adsorption of n-hexane and 3-methylpentane on zeolites Y and ZSM 20.- II. Kinetics of Adsorption and Fixed-Bed Processes.- Adsorption kinetics.- Dynamics of fixed-bed adsorbers. Isothermal adsorption of single components.- Asymptotic fixed-bed behavior: proportionate and constant patterns.- Pore scale hydrodynamics.- Separation processes based on electrosorption phenomena.- Adsorptive reactors.- Design aspects of fixed-bed adsorption processes.- Numerical methods for the solution of adsorption models.- III. Cyclic Processes and Simulated Moving Beds.- Gas separation by pressure swing adsorption using carbon molecular sieves.- Pressure swing adsorption technology.- Modeling and simulation of rate induced PSA separations.- Thermal swing adsorption.- On countercurrent adsorption separation processes.- Sorbex: continuing innovation in liquid phase adsorption.- IV. Applications in Biotechnology and Environmental Engineering.- The use of granular activated carbon for potable water treatment as an example of liquid phase applications of activated carbon.- Breakthrough time of organic vapours in activated carbon filters as a function of the air flow pattern.- Continuous adsorption in biotechnology.- Continuous chromatographic processes.- Biochemical reaction and separation in chromatographic columns.- Some factors involved in scale-up of industrial biotechnological adsorption processes.- Development of physical and mathematical modelling for scale-up of batch stirred tank and packed-bed column adsorption and chromatographic units.- Optimisation of adsorption techniques for the purification of biomolecules.- Gel filtration chromatography.- Adsorption chromatography for protein purification.- List of Lecturers and Participants.
199 citations
Patent•
01 Sep 1989TL;DR: In this paper, the phase separation process utilizes phase separation by means of thermally induced triggering or triggering induced by a non-solvent of a solution of the polymer in a mixture containing e-caprolactam as the essential dissolving constituent.
Abstract: A process produces microporous powders or shaped articles, in particular membranes in the form of flat films, tubular films or hollow fibers, which may be used for controlled release of an active compound, for dialysis, gas separation, ultrafiltration or microfiltration, from polyvinylidene fluoride and/or polyphenylene sulfide and/or polysulfone and/or polyacrylonitrile and/or ethylene/vinyl alcohol copolymer and/or ethylene/chlorotrifluoroethylene copolymer and/or polyethersulfone and/or polyether-imide and/or polymethyl methacrylate and/or polycarbonate and/or cellulose triacetate. The process utilizes phase separation by means of thermally induced triggering or triggering induced by a non-solvent of a solution of the polymer in a mixture containing e-caprolactam as the essential dissolving constituent. The solution may be formed before the phase separation is triggered.
144 citations
TL;DR: In this paper, the effect of the connecting group between bisphenol-A units on the gas separation characteristics of membranes formed from these polymers was examined and an unusually high He/CH4 selectivity was noted for one of the members in the series of polymers.
124 citations
TL;DR: In this paper, Tetraethoxysilane (TEOS) was introduced into the pores of porous glass and decomposed on the pore walls at 473 K. At the same time, a gas separation experiment using a helium-oxygen mixture was carried out.
109 citations
TL;DR: In this article, a series of polyimides prepared from 3,3,4,4′-biphenyltetracarboxylic dianhydride (BPDA) and each of the following diamines were measured for amorphous films.
70 citations
TL;DR: In this paper, temperature dependencies of gas permeabilities, solubilities, diffusivities, and selectivities for various gas pairs are reported for two hexafluoro-substituted aromatic polyimides prepared in a laboratory, and activation energies for gas permeation and diffusion, and the heats of sorption are also reported.
68 citations
Patent•
24 Jul 1989TL;DR: In this article, an improved method for dehydration and concentration of an aqueous solution containing an organic compound is disclosed, where the solution is evaporated to produce a gaseous mixture comprising an organic compounds vapor and a water vapor.
Abstract: An improved method for dehydration and concentration of an aqueous solution containing an organic compound is disclosed. The solution is evaporated to produce a gaseous mixture comprising an organic compound vapor and a water vapor. The water vapor is selectively removed from the gaseous mixture by permeation through an aromatic polyimide gas separation membrane while the gaseous mixture being kept in contact with a surface on one side of the gas separation membrane at a temperature of 70° C. or higher to obtain a gaseous mixture comprising the organic compound vapor and a reduced amount of a water vapor.
66 citations
Patent•
25 Jan 1989
TL;DR: In this article, a method of removing organic compounds from an air/permanent gas mixture is described, where the mixture is conveyed to a first gas separation membrane and is divided into a filtrate gas stream with organic compounds and a retained gas stream that is depleted of organic compounds.
Abstract: A method of removing organic compounds from an air/permanent gas mixture. This mixture, as untreated medium, is conveyed to a first gas separation membrane and is divided into a filtrate gas stream that is concentrated with organic compounds and a retained gas stream that is depleted of organic compounds. The concentrated filtrate is conveyed to a recovery device for the recovery of organic compounds therefrom. The pressure of the air/permanent gas mixture is raised prior to entry thereof into the first gas separation membrane. The pressure of the concentrated filtrate is reduced after exit thereof from the first gas separation membrane. The depleted gas stream is discharged into the atmosphere, and the gas stream that exits the recovery device is returned to the air/permanent gas mixture at some point subsequent to the pressure increase thereof.
60 citations
TL;DR: In this article, a new membrane module design has been developed for use in high recovery systems and at high gas flow rates for the production of methyl t-butyl ether (MtBE).
57 citations
Patent•
11 Dec 1989
TL;DR: In this paper, a gas membrane separator is used to allow oxygen to permeate there through selectively while restraining the passage of nitrogen, and the nonpermeant gas is then brought into contact with a second gas membrane separating with similar construction.
Abstract: Nitrogen gas of high purity is produced from compressed air by contacting the air with a first gas membrane separator permitting oxygen to permeate therethrough selectively while restraining the passage of nitrogen The nonpermeant gas is then brought into contact with a second gas membrane separator of similar construction The use of the serially arranged separators provides nitrogen gas with very low levels of oxygen
56 citations
TL;DR: In this article, a series of polyimide and polycarbonate materials are compared to conventional membrane materials to illustrate the value of a systematic structure-property approach to this topic.
TL;DR: The polymer poly (1,3-phenyl-1,4-pphenyl)-4,phenyl, 1,3, 4-triazole has been investigated for its gas separation properties as discussed by the authors.
Patent•
12 May 1989
TL;DR: In this article, an improvement of a known pressure swing adsorption process for separating a desired gas from a gas mixture using a cylinder containing an ad-sorption column is disclosed.
Abstract: An improvement of a known pressure swing adsorption process for separating a desired gas from a gas mixture using a cylinder containing an adsorption column is disclosed. The improvement resides in a procedure for regenerating the adsorption column for repeated use, which comprises returning a portion of the desired gas having been separated in the cylinder back into the cylinder at an intermittently varying rate to flow through the column, to efficiently desorb a gas component having been adsorbed by the adsorption column and purge away the desorbed gas from the cylinder.
Patent•
10 Oct 1989TL;DR: In this article, a process for improving the permselectivity of an aromatic polyimide gas separation membrane comprising contacting the membrane with a solution of a surfactant in a solvent which swells the membrane but in which the membrane material is soluble to an extent of no more than 3% under the conditions used to contact the membrane.
Abstract: A process for improving the permselectivity of an aromatic polyimide gas separation membrane comprising contacting said membrane with a solution of a surfactant in a solvent which swells the membrane but in which the membrane material is soluble to an extent of no more than 3% under the conditions used to contact the membrane.
Patent•
01 Sep 1989TL;DR: In this article, a composite of a rigid, glassy, permeable membrane of a silyl or germyl-containing polyacetylene and a thin surface layer of a plasma polymerized monomer having pendant nitrogen heterocycles is provided.
Abstract: A composite of a rigid, glassy, permeable membrane of a silyl or germyl-containing polyacetylene and a thin surface layer of a plasma polymerized monomer having pendant nitrogen heterocycles is provided; the composite has high flux and selectivity and is particularly useful for separating gas mixtures containing at least two components having different permeabilities through the composite structure.
Patent•
31 Jul 1989
TL;DR: A semi-permeable hollow fiber gas separation membrane with a non-external discriminating region fabricated from hydrophobic polymeric materials possessing less than about 1 weight percent equilibrium water content at about 25°C as discussed by the authors.
Abstract: The invention is a semi-permeable hollow fiber gas separation membrane possessing a non-external discriminating region fabricated from hydrophobic polymeric materials possessing less than about 1 weight percent equilibrium water content at about 25° C. The invention includes a process for making such membranes as well as a method of using such membranes.
TL;DR: In this paper, a laboratory membrane separation unit was assembled by using composite hollow fibers and tested in an automated apparatus for gas separation measurements for CH4/CO2 mixtures as functions of temperature, pressure, stage cut, feed gas composition, and flow regime.
Abstract: A laboratory membrane separation unit was assembled by using composite hollow fibers. It was tested in an automated apparatus for gas separation measurements. The performances of the system were measured for CH4/CO2 mixtures as functions of temperature, pressure, stage cut, feed gas composition, and flow regime. The results were analyzed on the basis of a predictive mathematical model of the process. A good fitting of the data was obtained in most cases except at high pressure, probably as a consequence of structural changes of the active layer of the fibers under pressurization.
Patent•
29 Jun 1989TL;DR: In this article, a semi-permeable membrane is proposed for separating gases using a thin discriminating layer of bisphenolic polycarbonate, polyester, or polyester carbonate, with a significant portion of the residues in the polymer backbone being based on tetrafluorobisphenol F.
Abstract: The invention is a semi-permeable membrane consituting a thin discriminating layer of bisphenolic polycarbonate, polyester, or polyestercarbonate, with a significant portion of the bisphenolic residues in the polymer backbone being based on tetrafluorobisphenol F. The invention also includes a method of separating gases using the described membrane.
Patent•
12 Sep 1989TL;DR: In this article, a polyimide gas separation membrane derived from alicyclic dianhydrides and aliphatic, alicycic, or aromatic diamines is described.
Abstract: This invention relates to novel polyimide gas separation membranes derived from alicyclic dianhydrides and aliphatic, alicyclic, or aromatic diamines, and a process for using such membranes.
Patent•
10 Oct 1989TL;DR: In this paper, a process for improving the permselectivity of asymmetric polyaramide gas separation membranes is described, which involves contacting the membrane with a dilute solution of a surfactant in a solvent which preferably swells the membrane material.
Abstract: A process for improving the permselectivity of asymmetric polyaramide gas separation membranes is disclosed. The process involves contacting the membrane with a dilute solution of a surfactant in a solvent which preferably swells the membrane material. The surfactants are anionic, nonionic or amphoteric with the fluorinated nonionic surfactants being preferred.
Patent•
07 Aug 1989TL;DR: In this article, a surface modified polymeric gas separation membrane having improved selectivity for oxygen/nitrogen gas mixtures is presented. But the membrane is not suitable for the separation of gases.
Abstract: The present invention provides a surface modified polymeric gas separation membrane having improved selectivity, particularly for oxygen/nitrogen gas mixtures, prepared by forming a membrane of a polymer having the structural formula ##STR1## wherein R and R" can be the same or different linear, branched or cyclic alkyl group having one to twelve carbon atoms, or R can be H, with the proviso that both R and R" cannot be methyl, and n is at least 100, and treating the surface of the membrane with a fluoro-oxidizing agent at conditions sufficient to fluoro-oxidize the membrane surface.
TL;DR: A novel air separation system based on permeable membrane gas separation technology was used to cultivate Escherichia coli and no by-product inhibition by acetate or CO2 was observed.
Abstract: A novel air separation system based on permeable membrane gas separation technology was used to cultivate Escherichia coli The system fulfilled the dissolved oxygen requirements of a culture of E coli grown on a glucose synthetic medium at a high and constant growth rate of 055 h-1 A biomass yield of 45 g (dry weight) per liter was achieved, and no by-product inhibition by acetate or CO2 was observed
TL;DR: In this article, the authors used the Monte Carlo method to compute equations of state for mixtures having intermolecular pair potentials of the form u(r)=e(σ/r)n, where n=12 and n=6.
Abstract: The Monte Carlo method is used to compute equations of state for mixtures having intermolecular pair potentials of the form u(r)=e(σ/r)n, where n=12 and n=6. Calculations are given for binary equimolar mixtures with additive diameters having the ratio σ1/σ2=3. In contrast to hard sphere mixtures, it is found that soft‐sphere mixtures have a positive volume of mixing at high pressures. For the mixture with n=6, this effect leads to the separation of two fluid phases at a pressure that is below the freezing point of the larger component. These results show that, under certain conditions, large differences in molecular size are sufficient to cause this type of phase separation. The ideal mixing and van der Waals one‐fluid (vdW1) theories are also discussed, and the predictions of these two models are compared with the Monte Carlo data. The vdW1 approximation gives satisfactory results at low pressures but is poorer than ideal mixing at high pressures.
TL;DR: In this paper, a two-dimensional diffusion equation model is presented to calculate the effective liquid membrane thickness in a hollow-fiber-contained liquid membrane gas permeator, taking into account the pressure variation inside the feed and the sweep fibers.
Patent•
23 Jan 1989TL;DR: In this paper, a semi-permeable cellulose ester gas separation membrane is constructed from a mixture of a cellulose mixture and a solvent selected from a group consisting essentially of glycerol acetate, glycerolic acid, diacetate, and triacetate.
Abstract: This invention relates to a novel composition useful for preparing a semi-permeable cellulose ester gas separation membrane, which composition includes a mixture of a cellulose ester, a solvent selected from the group consisting essentially of glycerol acetate, glycerol diacetate, glycerol triacetate, and mixtures thereof, and optionally the non-solvent glycerol. This invention also relates to a process of fabricating a cellulose ester gas separation membrane from said composition.
Patent•
23 Aug 1989TL;DR: Composite membrane (I) consists of: (i) a membrane of a film forming thermoplastic polymer contg a microporous, inorganic filler, in the filler has a specific surface area of 5-200 m2/g and is 60-90 wt% of the total wt of the membrane; (ii) a permiselective elastomeric separation film applied to the membrane as mentioned in this paper.
Abstract: Composite membrane (I) consists of: (i) a membrane of a film forming thermoplastic polymer contg a microporous, inorganic filler, in the filler has a specific surface area of 5-200 m2/g and is60-90 wt% of the total wt of the membrane; (ii) a permiselective elastomeric separation film applied to the membrane (2) Prepn of (I) comprises i) dispersing a filler with a specific surface area of 5-200 m2/g in 60-90 wt% in a soln of a film forming polymer contg a homogeneous casting soln with a viscosity of 500-15,000 cp; (ii) processing this soln into a membrane in the form of a foil pipe, tube or a hollow fibre, and removing the solvent by evaporation or coagulation by orecipitation; (iii) applying to the membrane a permiselective elastomeric separation film in the form of a soln of the elastomer followed by solvent removal by evaporation USE - (I) is used in pervaporation and gas separation processes
Patent•
11 Jul 1989TL;DR: In this paper, a process for producing integrally-skinned asymmetric poly(phenylene oxide) gas separation membranes is described, which involves forming a solution of the poly oxide in an aprotic solvent at an elevated temperature, forming a nascent membrane from the solution, partially drying the nascent membrane, followed by coagulating the partially dried nascent membrane in a coagulation bath formed from a non-solvent for the poly( phenylene oxide).
Abstract: A process for producing integrally-skinned asymmetric poly(phenylene oxide) gas separation membranes is disclosed. The process involves forming a solution of the poly(phenylene oxide) in an aprotic solvent at an elevated temperature, forming a nascent membrane from the solution, partially drying the nascent membrane, followed by coagulating the partially dried nascent membrane in a coagulation bath formed from a non-solvent for the poly(phenylene oxide) which non-solvent is miscible with said aprotic solvent.
TL;DR: The development of pressure swing adsorption technology for gas separation is quite tightly connected to the development of zeolitic and carbonaceous molecular sieves as discussed by the authors, which are nowadays successfully used in pressure swing adaption plants.
Abstract: The development of pressure swing adsorption technology for gas separation is quite tightly connected to the development of zeolitic and carbonaceous molecular sieves. The fact that certain carbonaceous materials have a molecular sieve effect is known a long time ago. This effect was observed during basic research on anthracite and bituminous coal which both are known to be porous. However, it was the development work of Bergbau-Forschung which resulted in an industrial production of carbon molecular sieves from certain hardcoal qualities. These carbon molecular sieves are nowadays successfully used in pressure swing adsorption plants for gas separation.1,2)