Carbon seals

Figure D-7. Carbon seal leakage calculation parameters. Reprinted by permission and courtesy ofA-C Compressor Corporation)...

Until now, flat silica membranes were only tested at relatively low temperatures (up to 300°C) because of limitations in thermal stability of the polymer sealing rings [2], However, with the use of dense alumina rings together with carbon sealing it is possible now to measure membrane properties (e.g. permeance) at much higher temperatures (up to 600°C), which will be described below. 

For the preparation of tubular silica membranes, commercially available mesoporous membranes [17] are used. These tubular supports have a total length of 25 cm and are enamelled at both ends, required for a gas-tight sealing with carbon seals to the reactor, so that an effective porous length of 20 cm remains. The tube consists of 4 layers. Layer 1, 2 and 3 consist of a-alumina with a thickness of 1.5 mm, 40 and 20 im and a pore diameter of 12, 0.9 and 0.2 im respectively. Layer 4 consists of y-alumina with a thickness of 3-4 im a Kelvin radius of 4 nm. A schematic drawing of the cross-section of a mesoporous support tube is provided in Figure 4. 

The tubular supports were measured in a membrane reactor, which could also serve for steamreforming experiments when applicable (Figure 6). The tubes were sealed with carbon sealing at the enamelled ends of the tubes. Permeance measurements were performed at 500°C. 

Another point concerns the membrane housing. Sealing between a ceramic membrane and a metallic tube can be a problem when high temperatures are used, due to the difference in thermal expansion between the two materials. Specific carbon seals can be used with classical fittings, but a much better system using a sequence of materials with progressive change in properties has been recently developed [83]. 

WEAR AND FRICTION OF IMPREGNATED CARBON SEAL MATERIALS IN LIQUID NITROGEN AND HYDROGEN... 

Has effect on binder for carbon seals and bearings Model 3010-1151. recommended. 

Lip Seals— Also called dust covers or carbon seals. Retards contamination of lube oil with dirty and humid air. 

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