An exemplary single bed reversing blower adsorption based air separation unit is configured to follow the O.sub.2 load placed thereon by adjusting flow rates therethrough and power consumption. At least one and preferably multiple pressure sensors sense O.sub.2 pressure within an O.sub.2 storage region downstream of an adsorber vessel. These sensed pressures are utilized to generate control signals controlling flow rates at locations upstream of the compressor, such as at a reversible blower and an output compressor. Control loops for the blower and the compressor are independent of each other and have different time constants. Effective following of the O.sub.2 load is thus achieved without driving the air separation unit into operational conditions outside of design and also maintaining optimal power consumption for the O.sub.2 produced, such that efficiency is maintained over a large turndown ratio.

The adsorption based air separation unit includes an adsorber vessel containing media which selectively adsorbs water vapor and nitrogen preferentially over oxygen. The vessel includes an air entry spaced from an oxygen discharge. At least one dry air tap from the adsorber vessel is located between the entry and the discharge. When the adsorption media is fresh, air entering the adsorber vessel passes through enough of the adsorber vessel to have much of its water vapor removed and only some of its nitrogen removed. The vessel can include multiple taps sequentially further from the entry which can be selectively opened as the adsorption media becomes saturated with water vapor and nitrogen, so that dry air with much of its nitrogen still present can be further tapped from the adsorber vessel. The adsorber vessel thus facilitates production of both oxygen and dry air, such as for use as medical grade air.

An air separation unit includes an air inlet with a reversible blower downstream therefrom and an adsorption bed filled with adsorption media downstream of the reversible blower. The adsorption bed contains an adsorption media which preferentially adsorbs nitrogen over oxygen. An oxygen and argon output is located downstream of the absorption bed. At least a portion of the mixed gas of oxygen and argon is routed to a modular argon separator which separates out at least a portion of the argon to provide high purity oxygen to a high purity oxygen outlet. The argon separator can be configured as a molecular sieve filter to separate the argon from the oxygen or the argon separator can be in the form of a gas cooler and condenser which condenses liquid oxygen for storage and discharge as substantially pure oxygen.

A driving system for a reversing blower adsorption based air separation unit is configured to not only drive the reversing blower cyclically in a forward and in a reverse direction, but also to allow the reversing blower to coast during a portion of its operating cycle. While coasting, a pressure differential across the blower acts alone to switch the reversing blower between a forward and a reverse direction of operation. Less power is thus required. When coasting, the blower can also be configured to output power such as the drive motor functioning as an electric generator or by having a mechanical power input be driven by the blower for power generation and/or energy storage. Such a system beneficially utilizes the energy associated with the pressure differential across the blower for energy harvesting and to further accelerate cycle times for the reversing blower adsorption based air separation unit.

An exemplary single bed reversing blower adsorption based air separation unit is configured to follow the O.sub.2 load placed thereon by adjusting flow rates therethrough and power consumption. At least one and preferably multiple pressure sensors sense O.sub.2 pressure within an O.sub.2 storage region downstream of an adsorber vessel. These sensed pressures are utilized to generate control signals controlling flow rates at locations upstream of the compressor, such as at a reversible blower and an output compressor. Control loops for the blower and the compressor are independent of each other and have different time constants. Effective following of the O.sub.2 load is thus achieved without driving the air separation unit into operational conditions outside of design and also maintaining optimal power consumption for the O.sub.2 produced, such that efficiency is maintained over a large turndown ratio.

Methods and systems for purifying argon from a crude argon stream are disclosed, employing pressure swing adsorption at cold temperatures from 186 C. to 20 C.; more preferably from 150 C. to 50 C.; and most preferably from 130 C. to 80 C. with oxygen-selective zeolite adsorbent. In some embodiments, the oxygen-selective zeolite adsorbent is a 4A zeolite, a chabazite, or a combination thereof.

The invention relates to a method and control system to control the speed of a centrifugal compressor operating within a vacuum pressure swing adsorption process to avoid an operation at which surge can occur and directly driven by an electric motor that is in turn controlled by a variable frequency drive. The claimed method determines the optimal speed for operation of the compressor along a peak efficiency operating line of a compressor map thereof. Speed of the compressor is adjusted by a feed back speed multiplier when the flow or other parameter referable to flow through the compressor is below a minimum and a feed forward multiplier during evacuation and evacuation with purge steps that multiplies the feed back multiplier to increase speed of the compressor and thereby avoid surge.

A oxygen concentrating system comprising an adsorption column having a first end and a second end, a shell enclosing the column and defining a product gas storage space between the column and the shell, a product conduit connecting the product gas storage space to a product output point, a first conduit comprising at least one first valve having at least a first and second configuration, in the first configuration, compressed air flows from the feed point to the first end, and, in the second configuration, waste gas flows from the first end to the waste point, and a second conduit comprising at least one second valve having at least a first and second configuration, in the first configuration, the product gas flows from the product gas storage space to the second end, and, in the second configuration, the product gas flows from the second end to the storage space.

The air separation unit includes a single adsorption bed downstream of a reversing blower and configured to operate on the principle of vacuum swing adsorption. An optimal ambient air pressure to vacuum pressure ratio within an adsorber vessel downstream of the reversible blower is identified. When the air separation unit is operated at ambient conditions where ambient air pressure is different, such as at higher altitude (or lower altitude) a pressure ratio across the blower when drawing a vacuum on the adsorption bed is maintained for optimal blower power to oxygen production performance. Time for recovery of the adsorption bed can also be modified due to the lower absolute pressure achieved within the adsorption bed when the pressure ratio across the blower is maintained. An ASU is thus provided which is optimized for performance at various different altitudes without requiring modification of equipment within the ASU.

The air filter assembly with charcoal canister includes an air filter and charcoal canister. The air filter and charcoal canister connect with each other by clamping. The charcoal canister and filter are connected with each other with compact structure and overall appearance. The assembling is simplified, and time and costs are saved.