A multi-unit system combines multiple single bed reversing blower vacuum swing adsorption air separation units together. The units feed a common O.sub.2 supply such as a system buffer tank. Demand is monitored and a number of individual units are brought online sufficient to meet demand. If demand exceeds supply, a further unit is brought online. If demand drops below supply by an amount greater than output of a single unit, then a longest operating unit is taken offline. The multi-unit system thus meets demand through utilization of multiple separate units in a highly redundant and highly reliable and scalable fashion.

Systems and methods for ammonia purification in the NH3 purification and liquefaction stage of a conventional two-column sour water stripping system using an adsorbent bed.

A method and apparatus for purifying air via a pre-purification unit (PPU) of an air separation unit (ASU) system can include passing air through a first adsorber of the PPU to purify the air for operation of the ASU system while it is at or below a first pre-selected operational capacity. In response to the operational capacity of the ASU system needing to be increased to a level above the first pre-selected operational capacity threshold, a second adsorber can be brought on-line in parallel with the first adsorber or in series with the first adsorber to provide improved purification capacity to account for the increased demand for purification capacity resulting from the increased operational capacity of the ASU system. This second adsorber can be different from the first adsorber (e.g. different in size, adsorption capacity for impurities within air, and/or configuration, etc.).

An air separation system includes an air separation module configured to receive feed air and separate the feed air into nitrogen-enriched air and oxygen-enriched air, a nitrogen-enriched air line for transporting the nitrogen-enriched air from the air separation module to a fuel tank for inerting, an oxygen sensing line connected to the nitrogen-enriched air line, a gas adsorption filter located in the oxygen sensing line, and an oxygen sensor downstream of the gas adsorption filter in the oxygen sensing line.

The present invention addresses to the use of NaY zeolite with a Si/Al ratio>2.6 as a solid adsorbent in the process of removing H.sub.2S from natural gas through a PSA process. The described adsorbent has the capacity of removing H.sub.2S from natural gas from offshore exploration platforms, enabling in situ regeneration. The experimental development proved the high capacity of capturing H.sub.2S by the NaY zeolite in consecutive cycles of pressurization, adsorption, depressurization and purging. This capture capacity remains at 74.2% of the initial capacity, remaining stable in subsequent cycles. The structure of the material maintained crystallinity above 95% in use, in 15 consecutive cycles, allowing the reuse of the adsorbent for a prolonged period of operation, preventing the solid from being constantly changed, which is quite common in a non-regenerative process.

A passive valve for use as a fixed leak valve. The valve includes a body having an internal chamber, first and second body ports in fluid communication with the chamber with the first port configured for fluid communication with a patient connection and the second body port configured for fluid communication with a ventilator, a body passageway in fluid communication with the chamber and with ambient air exterior of the body, and a check valve seal positioned to seal the body passageway to permit the flow of gas within the chamber through the body passageway to the exterior of the body and to prevent the flow of ambient air exterior of the body through the body passageway into the chamber. In alternative embodiments, the valve is incorporated into the patient connection or constructed as a separate part connectable to the patient connection.

An evaporative emission control canister system comprises an initial adsorbent volume having an effective incremental adsorption capacity at 25 C. of greater than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, and at least one subsequent adsorbent volume having an effective incremental adsorption capacity at 25 C. of less than 35 grams n-butane/L between vapor concentration of 5 vol % and 50 vol % n-butane, an effective butane working capacity (BWC) of less than 3 g/dL, and a g-total BWC of between 2 grams and 6 grams. The evaporative emission control canister system has a two-day diurnal breathing loss (DBL) emissions of no more than 20 mg at no more than 210 liters of purge applied after the 40 g/hr butane loading step.

Provided is a carbon dioxide removal apparatus that enables determination of whether or not carbon dioxide has desorbed from an adsorbent without using a carbon dioxide sensor. A carbon dioxide removal apparatus includes a carbon dioxide adsorption module, a first valve provided in an intake part of the carbon dioxide adsorption module, a second valve provided in a discharge part of the carbon dioxide adsorption module, a third valve connected to the discharge part, a vacuum pump connected to the carbon dioxide adsorption module via the third valve, and a controller. The carbon dioxide adsorption module includes a pressure meter and an adsorbent, and the controller is configured to perform, based on a pressure measured by the pressure meter, at least one of determining whether carbon dioxide has desorbed from the adsorbent or detecting an abnormality.