Membranes Gas

Fouling Industrial streams may contain condensable or reactive components which may coat, solvate, fill the free volume, or react with the membrane. Gases compressed by an oil-lubricated compressor may contain oil, or may be at the water dew point. Materials that will coat or harm the membrane must be removed before the gas is treated. Most membranes require removal of compressor oil. The extremely permeable poly(trimethylsilylpropyne) may not become a practical membrane because it loses its permeability rapidly. Part of the problem is pore collapse, but it seems extremely sensitive to contamination even by diffusion pump oil and gaskets [Robeson, op. cit., (1994)]. 

Status of Membrane Gas Separation Technology," Nitrogen 173, 25—29 (May—June 1988). 

Process Description Gas-separation membranes separate gases from other gases. Some gas filters, which remove hquids or sohds from gases, are microfiltration membranes. Gas membranes generally work because individual gases differ in their solubility and diffusivity through nonporous polymers. A few membranes operate by sieving, Knudsen flow, or chemical complexation. 

Hydrogen Hydrogen recovery was the first large commercial membrane gas separation. Polysulfone fiber membranes became available in 1980 at a time when H9 needs were rising, and these novel membranes qiiickly came to dominate the market. Applications include recovery of H9 from ammonia purge gas, and extraction of H9 from petroleum crackiug streams. Hydrogen once diverted to low-quahty fuel use is now recovered to become ammonia, or is used to desulfurize fuel, etc. H9 is the fast gas. 

In gas separation with membranes, a gas mixture at an elevated pressure is passed across the surface of a membrane that is selectively permeable to one component of the mixture. The basic process is illustrated in Figure 16.4. Major current applications of gas separation membranes include the separation of hydrogen from nitrogen, argon and methane in ammonia plants the production of nitrogen from ah and the separation of carbon dioxide from methane in natural gas operations. Membrane gas separation is an area of considerable research interest and the number of applications is expanding rapidly. 

Fig. 16.4. Schematic diagram of the basic membrane gas separation process.

In the present study, we fabricated hollow fiber membrane modules and performed experiments at several conditions. The energy consumption of this process is compared to those of conventional gas absorption processes and membrane gas separation processes. 

Foil of PTFE or polythene Chemical reagent + glass membrane Gas-sensing electrode H+ (or OH -) as an indirect measure of NH3, S02, nitrous vapours, H2S, HCN, CMXa), C02... 

Creed et al. [68] described a hydride generation inductively coupled plasma mass spectrometric method featuring a tubular membrane gas-liquid separator for the determination of down to 100 pg of arsenic in seawater. 

Membrane gas-separation systems have found their first applications in the recovery of organics from process vents and effluent air [5]. More than a hundred systems have been installed in the past few years. The technique itself therefore has a solid commercial background. Membranes are assembled typically in spiral-wound modules, as shown in Fig. 7.3. Sheets of membrane interlayered with spacers are wound around a perforated central pipe. The gas mixture to be processed is fed into the annulus between the module housing and the pipe, which becomes a collector for the permeate. The spacers serve to create channels for the gas flow. The membranes separate the feed side from the permeate side. 

Protoadamantene, isomerization of, 25 146,147 Proton exchange membrane, gas diffusion electrodes, 40 142-144... 

Membrane Gas Transport Gas Channel Flow Field Fuel Cell Sinele Fuel... 

Table 6.1. Surface Diffusion Data for Several Membrane/Gas Combinations f o,f s the Corrected Gas Phase Permeability x y/MT), the Corrected Surface...

Gas separation processes with membranes have undergone a major evolution since the introduchon of the first membrane-based industrial hydrogen separation process about two decades ago. The development of high selectivity mixed-matrix membranes will further advance the technology of membrane gas separation processes within the next decade. 

Figure 9. Idealized schematic of the cathode cataiyst iayer (going from z = 0 to z = L) between the membrane and cathode diffusion medium showing the two main iength scales the agglomerate and the entire porous electrode. Gray, white, and black indicate membrane, gas, and electrocatalyst, respectively, and the gray region outside of the dotted line in the agglomerate represents an external film of membrane or water on top of the agglomerate.

T0504 Medina Agricultural Products Company, Inc., Medina Bioremediation Products T0506 Membran Corporation, Membrane Gas Transfer... 

T0502 McLaren/Hart, Inc., IRV-100, IRV-150, and IRV-200 Thermal Desorption Systems T0504 Medina Agricnlmral Products Company, Inc., Medina Bioremediation Products T0506 Membran Corporation, Membrane Gas Transfer... 

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