Cyclic adsorption process using centrifugal compressors
AssigneePraxair Technology, Inc.
InventorsPaul W. Belanger, Michael S. Manning, Andrew C. Rosinski
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Abstract
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.
Claims23
A cyclic adsorption process comprising one or more adsorber vessels undergoing the steps of at least pressurization, depressurization, and purge in the cycle and driven by one or more variable speed centrifugal machines operating under acceleration and deceleration conditions adjusted to the steps, vessel size, and the process conditions employed, the improvement comprising operating the process such that the cycle time is greater than the ratio of the Δinertia to 0.3 times the total power of the one of more centrifugal machines that would be consumed in the absence of inertial effects.
A method of improving the power efficiency of a cyclic adsorption process using a positive displacement machine and containing one or more adsorber vessels undergoing the steps of at least pressurization and depressurization comprising replacing the positive displacement machine with a variable speed centrifugal machine;
- operating the centrifugal machine under acceleration and deceleration conditions adjusted to the steps, adsorber vessel size, and process conditions employed;
- and adjusting the process cycle time to be greater than the ratio of the calculated Δinertia to 0.3 times the centrifugal machine power consumption in the absence of inertial effects.
A pressure-swing adsorption process for cycling between a high pressure condition and a low pressure condition and wherein the cycle includes at least pressurization and depressurization steps, the process comprising cyclically operating at least one variable speed centrifugal compressor being in fluid communication with at least one adsorber vessel to accelerate from a low operating speed to a high operating speed to obtain the high cycle pressure condition and to decelerate from high operating speed to low operating speed to obtain the low cycle pressure condition whereby the cycle time is adjusted such that the centrifugal compressor is in a stonewall condition for a period of not more than 40 percent of the cycle time of the process under the conditions employed.
A method of using at least one centrifugal compressor for both the pressurization and depressurization steps of an adsorber vessel used in a pressure swing or vacuum swing adsorption process wherein the compressor is adjusted to the specific steps, adsorber vessel size, and process conditions employed, the method comprising:
- using a variable frequency drive to control the motor driving the centrifugal compressor from a low operating speed of not more than 7000 RPM to a high operating speed of greater than 13000 RPM;
- operating the compressor cyclically to accelerate from the low operating speed to a high operating speed and decelerate from high operating speed to low operating speed as required by the process;
- and wherein the compressor is in a stonewall condition for not more than 40 percent of the total cycle time of the process under the conditions employed.
Dependencies are inferred from the claim text.