Pressure swing adsorption – wikipedia b games basketball


Pressure swing adsorption processes utilize the fact that under high pressure, gases tend to be attracted to solid surfaces, or adsorbed. The higher the pressure, the more chapter 7 electricity and magnetism gas is adsorbed. When the pressure is reduced, the gas is released, or desorbed. PSA processes can be used to separate gases in a mixture because different gases tend to be attracted to different solid surfaces more or less strongly. If a gas mixture such as air is passed under pressure through a vessel containing an adsorbent bed of zeolite that attracts nitrogen more strongly than gas prices map oxygen, part or all of the nitrogen will stay in the bed, and the gas exiting the vessel will be richer in oxygen than the mixture entering. When the bed reaches the end of its capacity to adsorb nitrogen, it can be regenerated by reducing the pressure, thus releasing the adsorbed nitrogen. It is then ready for another cycle of producing oxygen-enriched air.

Aside from their ability to discriminate between different gases, adsorbents for PSA systems are usually very porous materials chosen gas equations chemistry because of their large specific surface areas. Typical adsorbents are activated carbon, silica gel, alumina, resin and zeolite. Though the gas adsorbed on these surfaces may consist of a layer only one or at most a few molecules thick, surface areas of several hundred square meters per gram enable the adsorption of a significant portion of the adsorbent’s weight in gas. In addition to their selectivity for different gases, zeolites and some types of activated carbon called carbon molecular sieves may utilize their molecular sieve characteristics to exclude some gas molecules from electricity jeopardy powerpoint their structure based on the size of the molecules, thereby restricting the ability of the larger molecules to be adsorbed.

Aside from its use to supply medical oxygen, or as a substitute for bulk cryogenic or compressed-cylinder storage, which is the primary oxygen source for any hospital, PSA has numerous other uses. One gas vs electric range of the primary applications of PSA is in the removal of carbon dioxide (CO 2) as the final step in the large-scale commercial synthesis of hydrogen (H 2) for use in oil refineries and in the production of ammonia (NH 3). Refineries often use PSA technology in the removal of hydrogen sulfide (H 2S) from hydrogen feed and recycle streams of hydrotreating and hydrocracking units. Another application of PSA is the separation of carbon dioxide from biogas to increase the methane (CH 4) ratio. Through PSA the biogas can be upgraded electricity test physics to a quality similar to natural gas. This includes a process in landfill gas utilization to upgrade landfill gas to utility-grade high purity methane gas to be sold as natural gas. [1]

• Industrial nitrogen generator units which employ the PSA technique produce high purity nitrogen gas (up to 99.9995%) from a supply of compressed air. But such gas stoichiometry PSA are more fitted to supply intermediate ranges of purity and flows. Capacities of such units are given in Nm³/h, normal cubic meters per hour, one Nm³/h being equivalent to 1000 liters per hour under any of several standard conditions of temperature, pressure, and humidity.

With this variation of PSA developed for use in Laboratory Nitrogen Generators generation of nitrogen gas is divided into two steps: in the first gas 85 vs 87 step, the compressed air is forced to pass through a carbon molecular sieve to produce nitrogen at a purity of approximately 98%; in the second step this nitrogen is forced to pass into a second carbon molecular sieve and the nitrogen gas reaches a final purity up to 99.999%. The purge gas from the second step is recycled and partially used as feed gas in the first step.

Rapid pressure swing adsorption or RPSA is frequently used in portable oxygen concentrators. It allows a significant reduction in the size arkansas gas association of the adsorbent bed when high purity is not essential and feed gas can be discarded. [7] It works by quickly cycling the gas 4 less redding ca pressure while alternately venting opposite ends of the column at the same rate. This means that unadsorbed gases progress along the column much faster and are vented at the distal end, while adsorbed gases do not get the chance to progress and are vented at the proximal end. [8] See also [ edit ]