Praxair Technology, Inc.

Andrew Chester Rosinski

Paul William Belanger

Michael S Manning

Mohamed Safdar Allie Baksh

James Smolarek

Bernard Thomas Neu

Yang Luo

Nicholas R Stuckert

Mark William Ackley

Garrett R Swindlehurst

Martin E Oehlbeck

Alan Barnard Stewart

Mohamed Safdar Baksh

Pedro Berges

Gerald Thomas O'Connor

Preeti Chandra

The present invention relates to a method and system for improving VPSA plant energy and capital efficiency through optimizing direct drive variable speed centrifugal feed, vacuum, and/or product compressors to achieve lower unit gas product production cost. More specifically, the present invention relates to a new energy efficient VPSA process and system which employs high speed direct drive centrifugal compressors to achieve wider production range. Significant lower energy consumption can be achieved over the plant operation life by employing compressors sized with average ambient and production demand, utilizing direct drive variable high speed centrifugal compressors' speed and operating range to meet the desired production demand. Since majority of the plants tend to run at below peak production most of operating life of the plant. In addition, the smaller size machine offers plant capital savings from the initial investment.

Energy efficient VPSA system with direct drive high speed centrifugal compressors

The invention relates to a method and system for improving PSA/VPSA plant energy efficiency during times of reduced production demand and capital efficiency through optimizing feed, vacuum, and centrifugal product compressors to achieve lower energy consumption and lower unit gas product production cost. More specifically, the present invention relates to a new energy efficient PSA/VPSA turn down process and system which employs high speed direct drive centrifugal product compressor to achieve desired production. Significant lower energy consumption can be achieved by employing lower flow, and lower adsorption top pressure in the lower production range.

The present invention relates to a method and control system to control the speed of centrifugal compressors 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, while subsequently operating the vacuum pressure swing process between set limits of highest adsorption and lowest desorption pressure. In accordance with present invention an optimal speed for operation of the compressor is determined at which the compressor will operate along a peak efficiency operating line of a compressor map thereof. This speed 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. The speed is then adjusted by a global speed factor which serves to adjust the average speed of the motors over all steps of the repeating cycle such that the process operates within high and low pressure limits.

Anti-surge speed control for two or more compressors

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.

Anti-surge speed control

A cyclic adsorption process is provided, the process containing one or more adsorber vessels undergoing the steps of at least pressurization and depressurization and driven by one or more variable speed centrifugal machines operating under acceleration and deceleration conditions and adjusted to the steps, vessel size, and process conditions employed, wherein the process cycle time is greater than the ratio of the change in inertia, defined the maximum energy that can be lost during a cycle due to inertia changes, to 0.3 times the total power of the one of more centrifugal machines that would be consumed in the absence of inertial effects.

Cyclic adsorption process using centrifugal compressors

The present invention relates generally to a cyclic adsorption process for separating components of a gas stream with at least one adsorber vessel containing at least one adsorber bed undergoing the steps of at least pressurization and depressurization such that the steps are driven by at least one compressor, the compressor undergoing the steps of acceleration and deceleration in association with the steps of pressurization and depressurization. The compressor is operated at or above predetermined speeds which do not generate undesirable frequency pulsations while meeting the requirements of the cyclic adsorption process.

Cyclic adsorption process using pulsation controlled compressors

A cyclic adsorption process is provided having pressurization and depressurization steps and driven by one or more centrifugal machines operating under acceleration and deceleration conditions wherein the deceleration rate of the machine is controlled to minimize power consumption and maximize the efficiency of the process. The operating speed of the centrifugal machine during deceleration is matched to the measured pressure ratio conditions so that the centrifugal machine arrives at its minimum operating speed near the point required to begin acceleration.

Cyclic adsorption process using centrifugal machines

A cyclic adsorption process is provided having pressurization and depressurization steps and driven by one or more centrifugal machines operating under acceleration and deceleration conditions wherein the deceleration rate of the machine is controlled to minimize power consumption and maximize the efficiency of the process. The operating speed of the centrifugal machine during deceleration is matched to the measured ratio pressure conditions so that the centrifugal machine arrives at its minimum operating speed near the point required to begin acceleration.

Systems and processes are provided for gas separation using high-speed induction variable-speed motors to accelerate and decelerate centrifugal compressors suitable for use in pressure swing adsorption (PSA) or vacuum pressure swing adsorption (VPSA) processes.

Systems and methods for gas separation using high-speed induction motors with centrifugal compressors

The present invention provides a method and a control system for controlling an adsorbent bed unit in which an adsorbent bed concentration of an impurity within an adsorbent bed of the adsorbent bed unit is measured. The adsorbent bed concentration is controlled by manipulating the feed cycle time during which an adsorbent bed is adsorbing the impurities to maintain the adsorbent bed concentration at a targeted adsorption bed concentration. The targeted adsorption bed concentration is determined such that the product impurity concentration is maintained at product impurity concentration targets. The method and control system can incorporate a supervisory level of control reactive to product impurity concentration levels and related targets to determine the targeted adsorption bed concentration and a primary level of control that calculates the feed cycle time based upon an error between the measured and targeted adsorption bed concentrations. Proportional integral control can be used for such purposes.

Adsorption control method and controller

Novel polybed VPSA process and system to achieve enhanced Orecovery are disclosed. The VPSA process comprises using three or more adsorber beds; providing a continuous feed supply gas using a single feed blower to one bed, wherein at any instant during the process, two beds are in an evacuation step and only one bed is in a feed mode; and purging the adsorber beds using two purge gases of different purity. The VPSA cycle may further comprise utilizing a storage device (e.g., a packed or empty equalization tank) to capture void gases during co-current depressurization step of the VPSA cycle, which is used at a later stage for purging and repressurization of the bed. In addition, the VPSA process employs a single feed compressor and two vacuum pumps at 100% utilization. Furthermore, the use of the storage device minimizes the use of product quality gas for purging. About 10-20% improvement in Oproductivity is realized in the new VPSA process.

Vacuum pressure swing adsorption process and enhanced oxygen recovery

The present invention generally relates to large capacity (e.g., greater than 350 tons/day O) vacuum pressure adsorption (VPSA) systems and processes that employ a single train including four beds, at least one feed compressor feeding two beds simultaneously at any given instant in time, and a single vacuum pump. The compressor(s) and the vacuum pump can be utilized 100% of the time. Use of product quality gas for purging is avoided, with about 10-20% improvement in Oproductivity and 5-10% reduction in capital cost expected.

Pressure swing adsorption process for large capacity oxygen production

The present invention relates to a PSA system using an indexing rotary dual valve regulating a stepping mode of operation that controls a variable bed inlet feed flow rate, controllable pressure between feed lines in different beds of the PSA system and varied output flow rate of product gas such as high purity hydrogen gas.

Indexing rotary dual valve for pressure swing adsorption systems

A three-bed pressure swing adsorption system providing a constant continuous supply gas, preferably containing a hydrogen component, in a multi-step and preferably in a twelve-step, process cycle that can produce a purified gas product, preferably hydrogen, on a constant flow.

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Orchard Park, NY, United States of America

Andrew Chester Rosinski