Process and apparatus for intermittent liquefaction operation that can support continuous air separation processing

Abstract

A process and apparatus for recovering at least nitrogen, oxygen and / or argon from a feed gas (e.g. air, process gas stream, etc.) can be configured to provide an improvement in operational efficiency with reduced electricity costs. Some embodiments can be adapted so that a substantially liquid feed can be fed for continuous separation processing while liquefaction of the feed may only occur intermittently during low electricity rate time periods. Some embodiments can utilize at least one tank for storage of the liquid feed received from a liquefaction processing unit for storage and use of the liquid feed for the continuous operation of the separation unit(s) utilized for separating desired product outputs from the liquified feed stored in the one or more tanks. The at least one tank can be a single tank or more than one tank (e.g. at least two tanks).

Description

PROCESS AND APPARATUS FOR INTERMITTENT LIQUEFACTION OPERATIONTHAT CAN SUPPORT CONTINUOUS AIR SEPARATION PROCESSINGCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority to U.S. Provisional Application No. 63 / 439,383 filed January 17, 2023 and is incorporated in its entirety herein by reference.FIELD

[0002] The present innovation relates to processes utilized to recover fluids from air or at least one process gas stream that can include at least nitrogen and oxygen in the air or gas (e.g. (a) nitrogen and oxygen, (b) nitrogen, oxygen and argon, (c) nitrogen, oxygen, argon, and at least one other gas such as neon, xenon, and / or krypton). The present innovation also relates to air separation units for separation of at least nitrogen and / or oxygen from air or other feed gas, gas separation plants configured to recover at least nitrogen, oxygen and / or argon from at least one feed gas, air separation plants, air separation systems, and methods of making and using the same.BACKGROUND

[0003] Air separation processing has been utilized to separate air into different constituent flows of fluid (e.g. nitrogen, oxygen, etc.). Examples of systems that were developed in conjunction with air separation processing include U.S. Pat. Nos. 4,022,030, 4,822,395, International Patent Publication Nos. W02020 / 169257, W02020 / 244801, WO 2021 / 078405 and U.S. Pat. App. Pub. Nos. 2019 / 0331417, 2019 / 0331418, and 2019 / 0331419.

[0004] Conventionally, air separation processes making cryogenic liquid products involve a gas feed being cooled to cryogenic temperatures and subsequently undergoing cryogenic processing for separation of different fluids from the feed, and the liquefaction of products is either integrated with the separation process or is downstream of the separation process.Cryogenic air separation is an energy intensive process, and liquefaction of product consumes similar or more power than separation of the constituent species. Steady-state operation is conventionally employed for air separation via distillation due to the stability and efficiency of the separation by distillation that can be obtained.SUMMARY

[0005] We have determined that ramping of an air separation plant may be desired to take advantage or periodic electricity pricing fluctuations or available periods of renewable power sources. Operating under such mode makes distillation system less stable and less efficient, and increases the capital cost of the plant. We have determined that air separation processes can be designed to better account for electricity pricing and demand so that low pricing periods of electricity can be leveraged for reduced operational costs while still supporting continuous air separation operations. Such designs can also permit embodiments to be able to be adapted for reduced greenhouse gas emissions associated with their operation by allowing for intermittent use of renewable power from renewable power sources (e.g. solar power or wind power) for electricity when those renewable power sources are available for use (e.g. daylight hours for use of solar power).

[0006] Embodiments can utilize at least one tank for storage of a substantially liquified air or other substantially liquified process gas (e.g. at least 95 volume percent (vol%) liquified, at least 90 vol% liquified, not less than 80 vol% liquefied, not less than 60 vol% liquefied between 100 vol% and 80 vol% liquid, between 100 vol% and 70 vol% liquid, between 100 vol% and 60 vol% liquid, etc.) for feeding to an air separation unit (ASU) that can include at least one column for separation of the liquified feed into product flows that include at least one nitrogen- enriched fluid (e.g. a nitrogen fluid that is between 98 vol% nitrogen and 100 vol% nitrogen, etc.) and / or at least one oxy gen-enriched fluid (e.g. an oxygen fluid that is between 98 vol%oxygen and 100 vol% oxygen, etc.). The product flows can also include an argon-enriched fluid, a neon-enriched fluid, a krypton-enriched fluid and / or a xenon-enriched fluid.

[0007] Embodiments can permit the vast majority of electricity consumption (or power consumption) in air separation and liquefaction to be consumed during low electricity cost, or low electricity demand time periods. This can provide improved electrical grid performance and also provide substantial operational cost reduction.

[0008] Embodiments can also permit utilization with renewable energy electricity sources (e.g. wind power or solar power) by providing flexibility in operation so liquefaction and the increased electrical demand such liquefaction can require to occur is operational when electricity from renewable power sources is available for use and is operated and provided so that the liquefaction processing is only operated intermittently (e.g. 4-20 hours a day, 6-18 hours in a day, 4-18 hours in a day, between 75 % and 90% of the time, between 20% and 80% of the time, 40 hours out of every 48 hours of operation, 40-65 hours out of every 72 hours of operation, etc.) while supporting continuous air separation operations (e.g. continuous distillation column operation that occur throughout all 24 hours in a day for one or more days in a row or one or more weeks in a row etc.) to provide stable and efficient distillation processing while also providing a substantial reduction in greenhouse gas emissions and lower operational costs.

[0009] In a first aspect, a process for separation of a feed gas comprising oxygen and nitrogen is provided. Embodiments of the process can include liquifying a feed gas to substantially liquify the feed gas to form a substantially liquified feed for a pre-selected time period via a liquefaction apparatus, and feeding the substantially liquified feed from the liquefaction apparatus to at least one tank during the pre-selected time period. The at least one tank can be connected to a separation processing apparatus to feed the substantially liquified feed from theat least one tank to the separation processing apparatus to form at least a first product and a second product. The process can also include feeding the substantially liquified feed from the at least one tank to the separation processing apparatus continuously for a continuous time period that includes the pre-selected time period and additional time so the separation processing apparatus operates to form at least the first product and the second product.

[0010] As can be appreciated from the above, the substantially liquified feed can be between 100 vol% liquid and 60 vol% liquid. For example, the substantially liquified feed can be at least 95 vol% liquid, at least 90 vol% liquid, not less than 80 vol% liquid, not less than 60 vol% liquid, between 100 vol% and 80 vol% liquid, between 100 vol% and 70 vol% liquid, or between 100 vol% and 60 vol% liquid. In some implementations, for example, the substantially liquified feed can be entirely liquid or can be between 85 volume percent (vol%) liquid and 100 vol% liquid.

[0011] In a second aspect, the feeding of the substantially liquified feed from the at least one tank to the separation processing apparatus can occur while the liquefaction apparatus is not operating during a day or week as well as when the liquefaction apparatus is operated for liquifying the feed gas during the pre-selected time period within the day or week. In some implementations, the pre-selected time period can be between 20 hours and 2 hours, 20 hours and 4 hours, between 20 hours and 6 hours, between 20 hours and 8 hours, between 20 hours and 12 hours, between 20 hours and 16 hours, between 20 hours and 18 hours, between 18 hours and 4 hours, between 18 hours and 6 hours, between 18 hours and 8 hours, between 18 hours and 16 hours or between 18 hours and 12 hours. In some situations, the pre-selected time period can be 16 hours out of every 72 hours of operation, can be 8-18 hours out of every 48 hours of operation, can be 16-24 hours out of every 72 hours of operation, or can be another suitable time period within a day or within a week of operation. In yet other embodiments, thepre-selected time period can be selected to provide intermittent operation over the course of one or more months of continuous operation of the separation apparatus.

[0012] In a third aspect, the separation processing apparatus utilized in the process can include a first column connected to a first tank of the at least one tank. The process can also include the first column receiving a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified and the first column receiving a second portion of the of the substantially liquified feed from the first tank after the second portion is at least partially vaporized via at least one heat exchanger of a compressor assembly arranged to cool a nitrogen-enriched stream output from the first column after compression of the nitrogen-enriched stream. The process can also include the first column receiving a third portion of the substantially liquified feed from the first tank after the third portion is at least partially vaporized via a condenser that is positioned to condense a product portion of the nitrogen-enriched stream output from the first column.

[0013] In some implementations, the third portion of the substantially liquified feed that is at least partially vaporized can be fed to the first column at a location below a location at which the second portion of the substantially liquified feed that is at least partially vaporized is fed to the first column. In other implementations, the third portion of the substantially liquified feed that is at least partially vaporized can be fed to the first column at a location that is at the same location at which the second portion of the substantially liquified feed that is at least partially vaporized is fed to the first column or is at about the same location which the second portion of the substantially liquified feed that is at least partially vaporized is fed to the first column.

[0014] In a fourth aspect, the process can also include a first column receiving a first portion of the substantially liquified feed from a first tank as a first feed stream that is substantially liquified. The first column can also receive a second portion of the substantially liquified feedfrom the first tank after the second portion is at least partially vaporized via a condenser that is positioned to condense a product portion of the nitrogen-enriched stream output from the first column. The first column can be a column of the separation apparatus and the first tank can be a first tank of the at least one tank that is connected to the first column for feeding substantially liquified fluid to the first column.

[0015] In some implementations, the second portion of the substantially liquified feed that is at least partially vaporized can be fed to the first column at a location below a location at which the first portion of the substantially liquified feed is fed to the first column. In other implementations, the second portion of the substantially liquified feed that is at least partially vaporized can be fed to the first column at a location that is at the same vertical location, at the same location, or at about the same location at which the first portion of the substantially liquified feed is fed to the first column.

[0016] In a fifth aspect, the first product can be a nitrogen-enriched liquid having a nitrogen content of between 100 volume percent (vol%) nitrogen and 98 vol% nitrogen. Also, the second product can be an oxygen-enriched liquid having an oxygen content of between 100 vol% oxygen and 98 vol% oxygen. Of course, other implementations can have first and second products of other nitrogen and oxygen concentrations that may be suitable for a particular set of design criteria.

[0017] In a sixth aspect, the at least one tank can be connected to the separation processing apparatus to feed the substantially liquified feed to the separation processing apparatus to form the first product, the second product, and a third product. The third product can be an argon- enriched fluid having an argon content of between 100 vol% argon and 80 vol% argon. Of course, other implementations use a third product having a different concentration of argon that may be suitable for a particular set of design criteria.

[0018] In a seventh aspect, the separation processing apparatus can include an argon enrichment column. Embodiments of the process can also include outputting an argon enrichment stream from a first column of the separation processing apparatus for feeding to the argon enrichment column.

[0019] In an eighth aspect, the liquification apparatus and the at least one tank can be sized relative to the separation processing apparatus so that a ratio of a feed rate of the substantially liquified feed fed to the at least one tank for the pre-selected time period to a feed rate at which the substantially liquified feed is fed from the at least one tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2. In other implementations, different ratios can be utilized. Examples of such ratios are discussed herein.

[0020] In a ninth aspect, embodiments of the process of the first aspect can be utilized within any suitable combination of the second, third, fifth, sixth, seventh, and / or eight aspects.

[0021] In a tenth aspect, embodiments of the process of the first aspect can be utilized within any suitable combination of the second, fourth, fifth, sixth, seventh, and / or eight aspects.

[0022] In an eleventh aspect, an embodiment of the process of the first aspect can be utilized in conjunction with other exemplary features of apparatuses or processes discussed herein.

[0023] In a twelfth aspect, an air separation apparatus is provided that can include a liquefaction apparatus positioned to liquify a feed gas to substantially liquify the feed gas to form a substantially liquified feed for a pre-selected time period. The apparatus can also include a first tank connected to the liquefaction apparatus to receive the substantially liquified feed from the liquefaction apparatus during the pre-selected time period and a separation processing apparatus connected to the first tank to receive the substantially liquified feed from the first tank continuously for a continuous time period that includes the pre-selected timeperiod and additional time so the separation processing apparatus is operable continuously throughout the continuous time period to form at least a first product and a second product.

[0024] As discussed above, it should be appreciated that the substantially liquified feed can be a feed that is at least 60 vol% liquid. For example, the substantially liquified feed can be between 100 vol% liquid and 60 vol% liquid. As another example, the substantially liquified feed can be at least 95 vol% liquid, at least 90 vol% liquid, not less than 80 vol% liquid, not less than 60 vol% liquid, between 100 vol% and 80 vol% liquid, between 100 vol% and 70 vol% liquid, or between 100 vol% and 60 vol% liquid. In some implementations, for example, the substantially liquified feed can be entirely liquid or can be between 85 volume percent (vol%) liquid and 100 vol% liquid.

[0025] In a thirteenth aspect, the air separation apparatus can include other elements. For example, the apparatus can include a feed pump connected between the first tank and the separation processing apparatus. Conduits, heat exchangers, vessels, expanders, compressors, valves, and other elements can also be utilized.

[0026] In a fourteenth aspect, the separation processing apparatus can include a first column connected to the first tank. The first column can be positioned to receive a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified. In some embodiments, the apparatus can also include a compressor connected to the first column to receive a nitrogen-enriched stream from the first column and at least one heat exchanger connected to the compressor to receive a compressed nitrogen-enriched stream from the compressor. The heat exchanger can also be connected to the first tank to receive a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and cool the compressed nitrogen-enriched stream. The heat exchanger can also be connected to the first column to feed the vaporized second portion of thesubstantially liquified feed to the first column as a second feed stream. In some implementations, a condenser can be positioned to receive a product portion of the compressed nitrogen-enriched stream output from the compressor and a third portion of the substantially liquified feed from the first tank to vaporize the third portion of the substantially liquified feed and condense the product portion of the compressed nitrogen-enriched stream. The condenser can also be connected to the first column to feed the vaporized third portion of the substantially liquified feed to the first column as a third feed stream.

[0027] I n a fifteenth aspect, the separation apparatus can include a compressor connected to the first column to receive a nitrogen-enriched stream from the first column and a condenser positioned to receive a product portion of a compressed nitrogen-enriched stream output from the compressor and a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and condense the product portion of the compressed nitrogen-enriched stream. The condenser can also be connected to the first column to feed the vaporized second portion of the substantially liquified feed to the first column as a second feed stream.

[0028] In a sixteenth aspect, the first product can be a nitrogen-enriched liquid having a nitrogen content of between 100 volume percent (vol%) nitrogen and 98 vol% nitrogen and the second product can be an oxygen-enriched liquid having an oxygen content of between 100 vol% oxygen and 98 vol% oxygen. Also, the substantially liquified feed can be entirely liquid or can be between 80 volume percent (vol%) liquid and 100 vol% liquid in some embodiments utilizing this aspect.

[0029] In a seventeenth aspect, the liquification apparatus and the first tank can be sized relative to the separation processing apparatus so that a ratio of a feed rate of the substantially liquified feed outputtable from the liquefaction apparatus for feeding to the first tank for thepre-selected time period to a feed rate at which the substantially liquified feed is fed from the first tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2. As noted above other implementations can utilize different ratios. Examples of such ratios are discussed herein.

[0030] In an eighteenth aspect, an embodiment of the twelfth aspect can utilize one or more of the thirteenth, fourteenth, sixteenth and / or seventeenth aspects. Or an embodiment of the twelfth aspect can utilize one or more of the thirteenth, fifteenth, sixteenth and / or seventeenth aspects.

[0031] In nineteenth aspect, embodiments of the air separation apparatus can be configured to utilize an embodiment of a process for separation of a feed gas discussed herein as well as other embodiments.

[0032] In a twentieth aspect, a process for separation of a feed gas comprising oxygen and nitrogen can include liquifying a feed gas to substantially liquify the feed gas to form a substantially liquified feed and feeding the substantially liquified feed from the liquefaction apparatus to at least one tank connected to a separation processing apparatus to feed the substantially liquified feed from the at least one tank to the separation processing apparatus for separation of the substantially liquified feed.

[0033] As discussed above, it should be appreciated that the substantially liquified feed can be a feed that is at least 60 vol% liquid. For example, the substantially liquified feed can be between 100 vol% liquid and 60 vol% liquid. As another example, the substantially liquified feed can be at least 95 vol% liquid, at least 90 vol% liquid, not less than 80 vol% liquid, not less than 60 vol% liquid, between 100 vol% and 80 vol% liquid, between 100 vol% and 70 vol% liquid, or between 100 vol% and 60 vol% liquid. In some implementations, for example,the substantially liquified feed can be entirely liquid or can be between 85 volume percent (vol%) liquid and 100 vol% liquid.

[0034] In some embodiments of the process, the first product can comprise liquid oxygen or liquid nitrogen. In other embodiments, the separation processing apparatus can operate to form at least a first product and a second product. The first product can comprise liquid nitrogen and the second product can comprise liquid oxygen.

[0035] In a twenty-first aspect, embodiments of the process of the twentieth aspect can also include feeding the substantially liquified feed from the at least one tank to the separation processing apparatus so the separation processing apparatus operates to form at least a first product.

[0036] In some embodiments, the liquifying of the feed gas to substantially liquify the feed gas to form a substantially liquified feed can be performed for a pre-selected time period and the feeding of the substantially liquified feed from the liquefaction apparatus to the at least one tank can occur during the pre-selected time period. The he feeding of the substantially liquified feed from the at least one tank to the separation processing apparatus can occurs continuously for a continuous time period that includes the pre-selected time period and additional time so the separation processing apparatus operates to form at least a first product.

[0037] In a twenty-second aspect, the pre-selected time period can be between 2 hours and 20 hours and the continuous time period can be at least 24 hours. Other embodiments can utilize other pre-selected time periods and continuous time periods.

[0038] In a twenty-third aspect, an air separation apparatus is provided. The apparatus can include a liquefaction apparatus positioned to liquify a feed gas to substantially liquify the feed gas to form a substantially liquified feed and a first tank connected to the liquefaction apparatus to receive the substantially liquified feed from the liquefaction apparatus. The first tank canalso be connectable to a separation processing apparatus to feed the substantially liquified feed from the first tank to the separation processing apparatus to form at least a first product.

[0039] Some embodiments can include the separation processing apparatus. In such embodiments, the separation processing apparatus can be configured to form the first product and at least one second product via separation of the substantially liquified feed.

[0040] The liquefaction apparatus can include a liquefier. The liquefier can be connected to the first tank to feed the substantially liquified feed to the first tank.

[0041] In a twenty-fourth aspect, embodiments of the twenty-third aspect can include other elements. For instance, an embodiment can include a feed pump connectable between the first tank and the separation processing apparatus. The separation processing apparatus can include first column connected to the first tank. The first column can be positioned to receive a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified. A compressor can be connected to the first column to receive a nitrogen- enriched stream from the first column and there can also be at least one heat exchanger connected to the compressor to receive a compressed nitrogen-enriched stream from the compressor. The heat exchanger can also be connected to the first tank to receive a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and cool the compressed nitrogen-enriched stream. The heat exchanger can also be connected to the first column to feed the vaporized second portion of the substantially liquified feed to the first column as a second feed stream.

[0042] In a twenty-fifth aspect, the liquification apparatus and the first tank can be sized relative to the separation processing apparatus so that a ratio of a feed rate of the substantially liquified feed outputtable from the liquefaction apparatus for feeding to the first tank for the pre-selected time period to a feed rate at which the substantially liquified feed is fed from thefirst tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2 or is another suitable ratio.

[0043] In a twenty-sixth aspect, an embodiment of the apparatus of the twenty -third aspect can include other elements as discussed herein. Embodiments can also be configured to implement at least one embodiment of a process for separation of air or a process gas that includes oxygen and nitrogen as discussed herein.

[0044] It should also be appreciated that embodiments of the process and / or the system can use a series of conduits for interconnection of different units so that different streams can be conveyed between different units. Such conduits can include piping, valves, and other conduit elements. The system can also utilize an automated process control system. Such a system can include sensors, detectors, and at least one controller to monitor operation of the system and / or provide automated or at least partially automated control of the system. Various different sensors (e.g. temperature sensors, pressure sensors, flow sensors, level controllers, etc.) can be connected to different conduits or system elements and be communicatively connected to at least one controller to facilitate automated control or semi -automated control of the system or processing of the system.

[0045] It should be also appreciated that different streams of fluid that can be utilized in the above discussed embodiments can include vapor, liquid, or a combination of vapor and liquid. Fluid streams that include vapor can include vapor, or gas.

[0046] Other elements can also be included in embodiments of the system that may be provided to utilize an embodiment of our process. For instance, one or more pre-treatment units, heat exchangers, expanders, adsorbers, pumps, compressors, fans, vessels, or other units can also be utilized in embodiments of the system. It should be appreciated that embodiments of thesystem or apparatus can be structured and configured to utilize at least one embodiment of the process.

[0047] Other details, objects, and advantages of our processes utilized to recover at least one fluid (e.g. nitrogen, oxygen, and / or argon etc.) from air, gas separation plants configured to recover nitrogen, oxygen and / or argon from at least one feed gas, air separation plants, air separation systems, systems utilizing multiple columns to recover nitrogen and / or oxygen fluids as well as optionally other fluids (e.g. argon, krypton, neon, xenon, etc.), plants utilizing such systems or processes, and methods of making and using the same will become apparent as the following description of certain exemplary embodiments thereof proceeds.BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Exemplary embodiments of processes utilized to recover at least one fluid (e.g. nitrogen, oxygen, and / or argon etc.) from air, gas separation plants configured to recover nitrogen, oxygen and / or argon from at least one feed gas, air separation plants, air separation systems, systems utilizing multiple columns to recover nitrogen and / or oxygen fluids as well as optionally other fluids (e.g. argon, krypton, neon, xenon, etc.), plants utilizing such systems or processes, and methods of making and using the same are shown in the drawings included herewith. It should be understood that like reference characters used in the drawings may identify like components.

[0049] Figure 1 is a schematic block diagram of a first exemplary embodiment of an air separation apparatus 1 utilizing a first exemplary embodiment of the air separation process. The air separation apparatus 1 can be configured for the separation of air or other process gas from a plant into two or more fluids (e.g. oxygen-enriched fluid, nitrogen-enriched fluid and / or at least one other enriched fluid).

[0050] Figure 2 is a schematic block diagram of a first exemplary embodiment of a separation processing apparatus 14 that can be utilized in the first exemplary embodiment of the air separation apparatus 1

[0051] Figure 3 is a schematic block diagram of a second exemplary embodiment of a separation processing apparatus 14 that can be utilized in the first exemplary embodiment of the air separation apparatus 1.

[0052] Figure 4 is a block diagram of an exemplary controller that can be utilized in exemplary embodiments of the air separation apparatus 1, which can use the first exemplary embodiment of the separation processing apparatus shown in Figure 2, the second exemplary embodiment of the separation processing apparatus 14 shown in Figure 3, or another configuration of a separation processing apparatus 14.DETAILED DESCRIPTION

[0053] Referring to Figures 1-4, a plant can include an air separation apparatus 1 that includes a liquefaction apparatus 3. The liquefaction apparatus 3 can include a compressor 2, a first heat exchanger 4, a pre-purification unit (PPU) 6, and a liquefier 8. The PPU 6 can be configured to utilize temperature swing adsorption, pressure swing adsorption, vacuum swing adsorption and / or other type of pre-purification processing. The compressor 2, first heat exchanger 4, and PPU 6 can be components of a feed pre-treatment apparatus 3a that can provide pre-treated feed to the liquefier 8 to form liquid feed for providing to at least one tank (e.g. first tank 10, etc.).

[0054] For instance, the compressor 2 can receive a feed gas (e.g. air, a plant process gas, etc.) and compress that gas to a first compressed feed gas pressure within a first compressed feed gas pressure range (e.g. a pressure of between 4 bara and 10 bara, etc.). The compressor 2 can output that compressed feed gas to a first HX 4 via a first HX feed conduit positioned betweenthe compressor 2 and the first HX 4 to cool the compressed gas before the compressed feed gas is fed to the PPU 6. A PPU feed conduit can be positioned between the first HX 4 and the PPU 6 to feed the cooled compressed feed gas from the first HX 4 to the PPU 6.

[0055] The PPU 6 can include one or more adsorbers that are configured to remove undesired constituents from the feed gas. Such undesired constituents can include, for example, carbon dioxide (CO2), and water (H2O). The PPU 6 can also be configured to remove other undesired constituents (e.g. a process gas constituent that may have an undesired temperature profile in which the constituent may freeze at a cryogenic operational temperature of the downstream liquefaction and separation processing or otherwise be unsuitable for subsequent separation processing). The purified compressed feed gas can be output from the PPU 6 and fed to a liquefier 8 via a liquefier feed conduit positioned between the PPU 6 and the liquefier 8.

[0056] The liquefier 8 can be configured to process the compressed feed gas output from the PPU 6 to liquify the compressed feed gas or at least substantially liquify that feed gas. A substantial liquefaction can be a liquefaction that is mostly liquid (e.g. the compressed feed gas is liquified such that an entirety of the gas is liquified, the compressed gas is liquified so between 95 vol% and 100 vol% of the gas is liquified, the compressed gas is liquified so between 90 vol% and 100 vol% of the gas is liquified, the compressed gas is liquified so between 85 vol% and 100 vol% of the gas is liquified, the compressed gas is liquified so between 80 vol% and 100 vol% of the gas is liquified, etc.). In a preferred embodiments, the compressed gas is liquified so that it is substantially liquified and is at least 80% liquid (e.g. the compressed gas is liquified so that the substantially liquified fluid is between 80 vol% and 100 vol% liquid) or at least 60% liquid (e.g. at least 95 vol% liquified, at least 90 vol% liquified, not less than 80 vol% liquefied, not less than 60 vol% liquefied, between 100 vol% and 80vol% liquid, between 100 vol% and 70 vol% liquid, between 100 vol% and 60 vol% liquid, etc.).

[0057] The cooled and substantially liquified compressed feed output from the liquefier 8 can be fed to a first tank 10 and / or a second tank 11 for storage therein. A first liquified feed conduit can be arranged and positioned between the first tank 10 and the liquefier 8 for feeding a first substantially liquified feed stream output from the liquefier 8 to the first tank 10. A second liquified feed conduit can be arranged and positioned between the second tank 11 and the liquefier 8 for feeding a second substantially liquified feed stream output from the liquefier 8 to the second tank 11. In some embodiments, there may be more than two tanks (e.g. there may also be a third tank (not shown) and a third substantially liquified feed stream conduit for conveying the third feed stream to the third tank). In other embodiments, there may only be a single first tank 10 and a first liquified feed conduit arranged and positioned between the first tank 10 and the liquefier 8 for feeding the first substantially liquified feed stream output from the liquefier 8 to the first tank 10.

[0058] For instance, in some embodiments, the purified compressed gas output from the compressor 2 can be split into at least two feed streams for feeding to the liquefier 8. In such embodiments, one or more of those streams may also undergo additional compression to be further compressed or may undergo expansion or pressure reduction to reduce the pressure of that stream of the split compressed feed gas. For instance, in such embodiments, a first feed stream of the compressed process gas (e.g. a first portion of the compressed feed gas output from the PPU 6 or output from the compressor 2) can be fed to the liquefier 8 for outputting a substantially liquefied compressed first feed stream at a first pressure within a first pressure range and fed to the first tank 10. A second feed stream of the compressed process gas (e.g. a second portion of the compressed feed gas output from the PPU 6 or compressor 2 that is splitfrom the first portion of the first feed stream) can be output from the liquefier 8 as a substantially liquefied compressed second feed stream at a second pressure within a second pressure range and fed to a second tank 11. It should be appreciated that each of the first and second feed streams fed to the first and second tanks 10 and 11 can be a substantially liquified feed stream or an entirely liquified feed stream.

[0059] Also, the second pressure and second pressure range of the second feed stream can differ from the first pressure and the first pressure range of the first feed stream. The second pressure can be greater than the first pressure (e.g. be set such that the second feed stream is considered a high pressure stream while the first feed stream is considered a low pressure stream) or can be less than the first pressure (e.g. be set such that the second feed stream can be considered a low pressure feed stream while the first feed stream is considered a high pressure stream).

[0060] In other embodiments, the liquefaction apparatus 3 can be configured to only form a first compressed and substantially liquified (or entirely liquified) feed stream for feeding to a first tank 10. In such embodiments, the compressed feed stream may not be split into separate portions for subsequently feeding to different tanks to maintain the substantially liquefied feed streams at different storage pressures.

[0061] In yet other embodiments, it is contemplated that there may be more than two split feed stream and more than the first and second tanks 10 and 11. For example, the compressed feed gas can be split to also form a third substantially liquified feed stream so the third feed stream output from the liquefier 8can be fed to a third tank (not shown). Such a third stream can undergo compression or pressure reduction in some embodiments so that the third stream is at a third pressure that differs from the pressure of the first stream and also differs from the pressure of the second stream. For instance, the third pressure can be a pressure that is withina third pre-selected pressure range that is considered an intermediate pressure (e.g. a pressure that is higher than a pre-selected low pressure and lower than a pre-selected high pressure).

[0062] The first tank 10 can be sized to retain a sufficient amount of compressed and substantially liquified feed for supporting continuous operation of a downstream separation processing apparatus 14 that can separate the constituents of the feed stream into at least a first product 16 (e.g. enriched nitrogen fluid or a nitrogen-rich fluid) and a second product 18 (e.g. enriched oxygen fluid or an oxygen-rich fluid). Some embodiments can also provide at least one third product stream (e.g. enriched argon, etc.).

[0063] In embodiments that may utilize more than one tank, each tank can be sized to retain a sufficient amount of the substantially liquified feed fed therein for supporting continuous operation of a downstream separation processing apparatus 14 that can separate the constituents of the feed stream into at least the first product 16 and second product 18.

[0064] It should be appreciated that the sizing and processing for the liquefaction apparatus 3 as well as the sizing for the first tank 10 and / or other tanks (e.g. second tank 11, etc.) can vary based on the overall size and processing requirements for a particular embodiment. The sizing of each tank as well as the sizing for the liquefaction apparatus 3 can be dependent upon the feed rate of feed that is needed to support the continuous, 24-hour-a-day operation of the separation processing apparatus 14 that may be performed for multiple consecutive days, weeks, or months while also accounting for the expected duration of the operation for the liquefaction apparatus 3 (e.g. operation within a time window that is less than 24 hours, such as 20 hours to 4 hours, 20 hours to 6 hours, 18 hours to 6 hours, or 18 hours to 4 hours, operation of the liquefaction apparatus 3 that may occur 20%-80% of the time, operation of the liquefaction apparatus that may occur 30-40 hours of every 48 hours or 40-65 hours of every 72 hours of operation, etc.). . In some implementations, the continuous operation ofthe separation processing apparatus 14 can be performed so that separation can occur in a substantially steady-state condition or a substantially steady-state condition (e.g. operated at a production rate that is within 30% of being at steady state or operated at a production rate to be within 15% of steady state) while also accounting for the expected duration of the operation for the liquefaction apparatus 3.

[0065] The liquefaction apparatus 3 can also (or alternatively) be configured to supply liquid feed or substantially liquid feed for multiple days in a row continuously and subsequently be deactivated for one or more days. The first tank 10 can be sized and configured to accommodate storage of sufficient liquid feed or substantially liquid feed to accommodate such operation (and non-operation) of the liquefaction apparatus to support continuous operation of the separation processing apparatus 14 for a time period that includes the pre-selected time period of operation for the liquefaction apparatus 3 as well as additional time (e.g. one or more days of non-use of the liquefaction apparatus 3, 2-20 hours of non-operation of the liquefaction apparatus 3, etc.).

[0066] For instance, in situations where the liquefaction apparatus 3 may only be expected to operate for six hours, the liquefaction apparatus 3 can be sized to produce a sufficient flow rate of substantially liquefied feed in this six hour window for providing feed to the separation processing apparatus 14 for 24 hours of operation of the separation processing apparatus 14 and the size of each tank being fed substantially liquified feed can be sized to receive three to four times the amount of substantially liquified feed needed for supporting 24 hours of continuous operation of the separation processing apparatus in a substantially steady-state condition for the 18 hours the liquefaction apparatus 3 is not operating and is off-line in addition to the six hours the liquefaction apparatus is operational.

[0067] As another example, in situations where the liquefaction apparatus 3 may only be expected to operate for 18 hours, the liquefaction apparatus 3 can be sized to produce a sufficient flow rate of substantially liquefied feed in this 18 hour operational window for 24 hours of continuous operation of the separation processing apparatus 14 in its desired operational condition and the size of each tank being fed substantially liquified feed can be sized to receive 1.366 to 1.5 times the amount of substantially liquified feed needed for supporting 24 hours of continuous operation of the separation processing apparatus for the 6 hours the liquefaction apparatus 3 is not operational and is off-line in addition to the 18 hours in which the liquefaction apparatus 3 is operating.

[0068] As yet another example, in situations where the liquefaction apparatus 3 may only be expected to operate for 56 hours of every 72 hours of operation of the apparatus 1, the liquefaction apparatus 3 can be sized to produce a sufficient flow rate of substantially liquefied feed in this 56 hour operational window for 72 hours of continuous operation of the separation processing apparatus 14 in its desired condition and the size of each tank (e.g. first tank 10, first tank 10 and second tank 11, etc.) being fed substantially liquified feed can be sized to receive 1.3 to 2.5 times the amount of substantially liquified feed needed for supporting 72 hours of continuous operation of the separation processing apparatus for the 16 hours the liquefaction apparatus 3 is not operational and is off-line in addition to the 56 hours in which the liquefaction apparatus 3 is operating. It should be appreciated that the size of each tank being fed substantially liquified feed can be sized to receive over one to four times the amount of substantially liquified feed needed for supporting 24 hours of continuous operation of the separation processing apparatus in a substantially steady-state condition for the 16 hours the liquefaction apparatus 3 is not operating and is off-line in addition to the 56 hours the liquefaction apparatus 3 is operational.

[0069] As yet another example, in situations where the liquefaction apparatus 3 may only be expected to operate for 30-40 hours of every 48 hours of operation of the apparatus 1, the liquefaction apparatus 3 can be sized to produce a sufficient flow rate of substantially liquefied feed in this 30-40 hour operational window for 48 hours of continuous operation of the separation processing apparatus 14 in its desired condition and the size of each tank being fed substantially liquified feed can be sized to receive 1.2 to 2.2 times the amount of substantially liquified feed needed for supporting 48 hours of continuous operation of the separation processing apparatus for the 8-18 hours the liquefaction apparatus 3 is not operational and is off-line in addition to the 30-40 hours in which the liquefaction apparatus 3 is operating. It should be appreciated that the size of each tank being fed substantially liquified feed can be sized to receive over one to four times the amount of substantially liquified feed needed for supporting 48 hours of continuous operation of the separation processing apparatus in a substantially steady-state condition for the 8-18 hours the liquefaction apparatus 3 is not operating and is off-line in addition to the 30-40 hours the liquefaction apparatus 3 is operational.

[0070] The liquefaction apparatus 3 and tank sizing can permit storage of accumulated feed so that when the liquefaction apparatus 3 does not operate during high electricity pricing time periods or time periods when the electricity cannot be provided by a renewable power source (e.g. solar panels or at least one wind turbine, etc.), there is sufficient stored liquified feed in the at least one tank (e.g. first tank 10 and / or second tank 11, etc.).

[0071] It is contemplated that embodiments can include a liquefaction apparatus 3 sized for continuous operation for between 4 hours and 20 hours at a feed flow rate that is sufficient to provide feed to at least one tank (e.g. first tank 10) for supporting at least 24 hours of continuous operation of the separation processing apparatus 14. At least one substantially liquefied feedstorage tank (e.g. first tank 10) can be sized to retain the liquified feed from the liquefaction apparatus 3 so that excess feed provided during operation of the liquefaction apparatus 3 is stored for subsequently providing that stored feed to the separation processing apparatus 14 to support continuous operation of the separation processing apparatus through the day even while the liquefaction apparatus 3 is not operational or being operated to provide liquid feed for the separation processing apparatus 14. In such embodiments, the liquefaction apparatus 3 can be sized so that the substantially liquified feed flow rate is provided at a ratio of 6 / 5 to 6 / 1 (or 6:5 to 6: 1) relative to the feed rate the separation processing apparatus 14 needs to be able to operate continuously for 24 hours in a day at a substantially steady-state operational condition.

[0072] For example, for a liquefaction apparatus 3 designed to operate continuously for 18 hours in a pre-selected operational window, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be 4:3, or 4 / 3, such that the liquified feed flow rate fed to the tank(s) is 33% higher than the feed rate needed by the separation processing apparatus 14 so the tank(s) can store sufficient feed for continuous substantially steady-state operation of the separation processing apparatus 14 for 24 hours in a day (e.g. the tank(s) have sufficient feed to support continuous stead state operation of the separation processing apparatus 14 for the six hours the liquefaction apparatus is not running). For a liquefaction apparatus 3 designed to operate continuously for 4 hours in a pre-selected operational window, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be 6: 1, or 6 / 1, such that the liquified feed flow rate is sextuple the feed rate needed by the separation processing apparatus 14 so that the tank(s) can store sufficient feed for continuous substantially steady-state operation of the separation processing apparatus 14 for 24 hours in a day (e.g. for the 20 hours a day the liquefaction apparatus 3 may not run while the separation processing apparatus 14 is operated). For aliquefaction apparatus 3 designed to operate continuously in a 6 hour operational window, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be 4: 1, or 4 / 1, such that the liquified feed flow rate is quadruple the feed rate needed by the separation processing apparatus 14 so the tank(s) can store sufficient feed for continuous substantially steady-state operation of the separation processing apparatus 14 for 24 hours in a day (e.g. the tank(s) can feed the separation processing apparatus 14 for the 18 hours the separation processing apparatus can operate without the liquefaction apparatus 3 running). As yet another example, for a liquefaction apparatus 3 designed to operate for 12 hours, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be 2: 1, or 2 / 1, such that the liquified feed flow rate is double the feed rate needed by the separation processing apparatus 14 so the tank(s) can store sufficient feed for continuous operation of the separation processing apparatus 14 for 24 hours in a day (e.g. the tank(s) can store sufficient liquid feed for supporting 12 hours of operation of the separation processing apparatus that can occur without the liquefaction apparatus 3 running).

[0073] It is also contemplated that embodiments can include a liquefaction apparatus 3 sized for intermittent operation at a feed flow rate that is sufficient to provide feed to at least one tank (e.g. first tank 10) for supporting at least 48 hours or at least 72 hours of continuous operation of the separation processing apparatus 14 or other type of multiple day or multiple week time period. At least one substantially liquefied feed storage tank (e.g. first tank 10) can be sized to retain the liquified feed from the liquefaction apparatus 3 so that excess feed provided during operation of the liquefaction apparatus 3 is stored for subsequently providing that stored feed to the separation processing apparatus 14 to support continuous operation of the separation processing apparatus through the multiple days in a row (or weeks in a row) even while the liquefaction apparatus 3 is not operational or not being operated to provideliquid feed for the separation processing apparatus 14 during one or more intermittent time ranges throughout those days or weeks (e.g. the 48 hour or 72 hours of continuous operation of the separation processing apparatus 14). In such embodiments, the liquefaction apparatus 3 can be sized so that the substantially liquified feed flow rate is provided at a ratio relative to the feed rate the separation processing apparatus 14 needs to be able to operate continuously for 24 hours a day operation throughout the multiple days or weeks at a substantially steadystate operational condition.

[0074] For example, for a liquefaction apparatus 3 designed to operate continuously for 40 hours of 48 hours in at least one pre-selected operational window, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be 6:5, or 6 / 5, such that the liquified feed flow rate fed to the tank(s) is 20% higher than the feed rate needed by the separation processing apparatus 14 so the tank(s) can store sufficient feed for continuous substantially steady-state operation of the separation processing apparatus 14 for the entire 48 hours (e.g. the tank(s) have sufficient feed to support continuous stead state operation of the separation processing apparatus 14 for the eight hours the liquefaction apparatus is not running during this 48 hour time period). For a liquefaction apparatus 3 designed to operate continuously for 50-60 hours out of every 72 hours in at least one pre-selected operational window, the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can be between 36:25 and 6:5 such that the liquified feed flow rate is at a higher feed rate than the rate needed by the separation processing apparatus 14 so that the tank(s) can store sufficient feed for continuous substantially steady-state operation of the separation processing apparatus 14 for 72 hours (e.g. for the 12-22 hours the liquefaction apparatus 3 may not run while the separation processing apparatus 14 is operated). It should appreciated that the one or more tanks (e.g. first tank 10 or first tank 10 and second tank 11,etc.) can store sufficient liquid feed for supporting continuous hours of operation of the separation processing apparatus that can occur while the liquefaction apparatus 3 is only intermittently operational during that time period (e.g. does not operate for one or more non- operational time slots within the continuous operational cycle of the separation processing apparatus 14).

[0075] The first tank 10 (and / or other tanks, e.g. second tank 11) can be sized to receive the excess feed from the liquefaction apparatus 3 for storing feed therein that is supplied in excess of what is needed by the separation processing apparatus 14 so the excess feed can be retained and accumulated within the tank while both the liquefaction apparatus 3 and the separation processing apparatus 14 are operating at the same time (e.g. both operating within the preselected operational window of the liquefaction apparatus 3). Each tank can be sized to retain sufficient feed fed therein so that after the liquefaction apparatus 3 stops operations for a day or other pre-selected operational time period cycle (e.g. during a high electricity pricing time period or a time period in which a renewable power source may not be utilizable such as night for use of solar power, etc.), the tank(s) have sufficient substantially liquified feed stored therein so that the stored feed can be continued to be fed to the separation processing apparatus 14 at a pre-selected feed rate for substantially steady-state operation of the separation processing apparatus 14 while the liquefaction apparatus 3 is no longer running so the separation processing apparatus 14 is able to run at substantially steady-state operational condition for the entire 24 hours of the day each day.

[0076] This sizing difference can result in the liquification apparatus 3 being sized to provide a substantially larger output rate of substantially liquified feed than may be needed by the separation processing apparatus 14. Also, the size of each tank can be configured to facilitate accumulation of sufficient feed to permit accumulation of feed therein while the liquefactionapparatus 3 runs and also a reduction of feed stored in the tank for when the liquefaction apparatus 3 is not running. Because tanks may need to avoid being over filled and also avoid being entirely emptied to support pump operations for feeding feed from the tank(s) to the separation processing apparatus 14, the sizing of the tank(s) as well as the exact ratio for the substantially liquified feed rate output from the liquefaction apparatus 3 relative to the feed rate needed by the separation processing apparatus 14 may vary somewhat to account for pump operational performance, tank geometry, and a pre-defined safety factor that may be set to avoid each tank being entirely emptied while the liquefication apparatus is off. The above noted ratios ranges (e.g. a ratio of 6:5 to 6: 1) may therein be further adjusted by a pre-selected safety factor. This safety factor can be between 5% and 25% in some embodiments (e.g. the ratio may range from 6.3:5 to 6.3: 1 when a 5% safety factor is applied or may range from 7.5:5 to 15:2 when a 25% safety factor is applied). It should therefore be understood that the above noted ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 can range from 6:5 to 15:2 (or 6:5 to 7.5: 1) in some embodiments.

[0077] Of course, other safety factors can be applied as may be selected by an operator to account for a particular set of design criteria (e.g. size and geometry of tank, type of electricity demand or renewable power to be utilized, potential dangers associated with the tank(s) being fully emptied or over filled, etc.). The above noted safety factor adjustments for the ratio for the feed rate to the tank(s) relative to the feed rate to the separation processing apparatus 14 should therefore be understood to be exemplary in nature.

[0078] The separation processing apparatus 14 can receive the substantially liquified feed from the first tank 10 via a pump 12 that is connected to a separation processing apparatus feed conduit between the first tank 10 and the separation processing apparatus 14 for feeding the compressed and cooled substantially liquified feed within the first tank 10 to the separationprocessing apparatus 14. In embodiments that utilize a second tank 11, a second pump (not shown) can also be provided for feeding the feed stored in the second tank 11 to the separation processing apparatus 14 as well. Alternatively, the pump 12 can be connected to the second tank 11 to drive a feed of fluid from both the first tank 10 and the second tank 11 to the separation processing apparatus 14.

[0079] The separation processing apparatus 14 can receive the substantially liquified feed from the first tank 10 via the feed pump 12 to process that feed to separate the feed into at least two output flows to provide at least a first product 16 and a second product 18. At least one third product 20 (shown in broken line in Figure 1) can also be produced in some embodiments. The first product 16 that is formed can be a flow of nitrogen-enriched fluid and the second product 18 that is formed can be a flow of oxygen-enriched fluid. In embodiments that may form a third product, the third product 20 can be flow of argon-enriched fluid or other type of enriched fluid.

[0080] The separation processing apparatus 14 can include a column assembly 15 that has at least one distillation column. In some configurations, the at least one distillation column of the column assembly 15 can include a multiple column tower having multiple columns. As another example, the separation processing apparatus 14 can include a series of distillation columns. For instance, in some embodiments, there can be a first column of a column assembly 15 as well as an argon enrichment column (ArE) 39 (shown in broken line in Figure 2). The ArE 39 can be positioned to receive an output stream 28 from the column assembly 15 that is enriched with argon for providing a third product 20 that can include an argon-rich or an argon-enriched product. In some configurations, the ArE can be a second column of the column assembly 15 that is within a multiple column tower of the column assembly 15. In other arrangements, sucha column may be positioned remote from the first column of the column assembly 15 and be connected to the first column via a plurality of conduits.

[0081] When utilized, the ArE 39 can be arranged and positioned to provide third product 20. In some configurations, an argon-enriched stream output from the ArE 39 can undergo further processing for forming an argon-rich stream (e.g. via de-oxygenation, pressure swing adsorption, or a getter treatment, etc.).

[0082] In other embodiments, there can be only a single separation column utilized in the column assembly 15 of the separation processing apparatus 14.

[0083] The separation processing apparatus 14 can also include other process units that facilitate separation of the feed into multiple flows of desired products for storage and / or use by a plant process or for storage and subsequent distribution to a customer or end user.

[0084] Embodiments of the air separation apparatus 1 can also include additional elements in the liquefaction apparatus 3. For example, the liquefaction apparatus 3 can be configured to utilize cryogenic flash unit, a pressure swing adsorption (PSA) unit, or a vacuum swing adsorption (VSA) unit so that stored liquified feed within the first tank 10 and / or second tank 11 is nitrogen-enriched or oxygen-enriched. In some configurations, it is contemplated that such a system can be utilized so a first tank 10 stores a nitrogen- enriched liquified feed that is substantially liquid or entirely liquid and a second tank 11 stores an oxygen-enriched liquified feed that is substantially liquid or entirely liquid. In other configurations, such a system can be utilized so that the first tank 10 stores an oxygen-enriched liquified feed that is substantially liquid or entirely liquid and the second tank 11 stored a nitrogen-enriched liquified feed that is substantially liquid or entirely liquid. In yet other configurations, there may be only a single first tank 10 and that tank may store an oxygen-enriched liquified feed or a nitrogen-enriched liquified feed where that stored feed is substantially liquid or entirely liquid. Suchconfigurations of the air separation apparatus 1 can be utilized when the feed to be liquified via the liquefaction apparatus 3 is air or is a process gas received from a plant unit or plant process.

[0085] Figures 2 and 3 illustrate examples of separation processing apparatuses 14 that can be utilized in an embodiment of the air separation apparatus 1. It should be understood that these are examples and that other configurations are also utilizable.

[0086] Referring to Figure 2, illustrates an exemplary embodiment that can utilize a compressor or series of compressors in a cold configuration or a cryogenic configuration in which the compressor(s) compress fluid at a temperature range that can be considered cryogenic, for example. In the exemplary separation processing apparatus 14 of Figure 2, the substantially liquified feed stored in the first tank 10 can be fed to a first column of a column assembly 15 via a column feed conduit. A feed pump 12 can be positioned in fluid communication with the first tank 10 and the column feed conduit to drive the flow of substantially liquified feed or entirely liquified feed from the first tank 10 to the first column of the column assembly.

[0087] The feed pump 12 can be positioned and arranged so that the substantially liquified feed or entirely liquified feed output from the first tank 10 for being fed to a first column of a column assembly 15 is at least at an operating pressure of the first column. This operating pressure can be a pre-selected operating pressure that is within an operational pressure range of 1 bara to 10 bara.

[0088] The substantially liquified feed or entirely liquified feed output from the first tank 10 can be split into different portions for providing different feed streams to different elements of the separation processing apparatus 14 before those streams are then fed to the first column of the column assembly 15. For example, a first portion of the feed, or first feed stream 40 of the feed can be fed to the first column of the column assembly 15 via the column feed conduit.

[0089] A second portion of the feed can be split upstream of the column assembly 15 to form a second feed stream 41 for being fed to second and third heat exchangers (e.g. second HX 32 and third HX 24) of a compressor assembly that is positioned for cooling enriched nitrogen fluid output from the first column of the column assembly 15 as a nitrogen-enriched steam 48 after that fluid has undergone compression in at least one compressor or an array of compressors that include a second compressor (also referred to as “second comp.” ) 31 and a third compressor (also referred to as “third comp ”) 33 that is downstream of the second compressor 31.

[0090] In some embodiments, the compressor assembly can include a single multiple stage compressor having different stages of a single multiple stage compressor. For example, the second compressor 31 can be a first stage or first set of stages of a single multi-stage compressor and the third compressor 33 can be a second stage or second set of stages of a multi-stage compressor that is downstream of the first stage or first set of stages. In other arrangements, the compressor assembly can include multiple compressors or multiple multistage compressors (e.g. the second compressor 31 can be a single stage compressor or a multistage compressor and the third compressor 33 can be a single stage compressor or a multi-stage compressor).

[0091] The second HX 32 can be positioned between the second compressor 31 and the third compressor 33 to cool compressed nitrogen-enriched fluid output from the second compressor 31 via a portion of the second feed stream 41 and also warm the portion of the second feed stream 41 fed therein for cooling nitrogen-enriched fluid output from the second compressor 31. The third HX 34 can be positioned to cool compressed nitrogen- enriched fluid output from the third compressor 33 via a portion of the second feed stream 41 and also warm the portionof the second feed stream 41 fed therein for cooling the nitrogen-enriched fluid output from the third compressor 33.

[0092] The warmed second feed stream 43 output from the second HX 32 and the third HX 34 can be fed to the first column of the column assembly 15 via a warmed second stream feed conduit connected between the column assembly 15 and the second and third heat exchangers 32 and 34. The warmed second feed stream 43 can be fed to the first column at a location that is the same or lower than a location at which the first feed stream 40 is fed to the first column.

[0093] A third portion of the feed output from the first tank 10 can be split to form a third feed stream 42 for being fed to a condenser 35. The condenser 35 can be a condenser of a reboilercondenser, a heat exchanger (HX), or other type of suitable condenser that can condense a product portion of a nitrogen-enriched steam 48 output from the first column of the column assembly 15 after it has been compressed by at least the second compressor 31. A product portion 47 of the nitrogen-enriched steam 48 can be split from the nitrogen-enriched steam 48 after it is output from the second compressor 31 and also output from the second HX 32. A nitrogen product portion feed conduit connected between the second compressor 31 and the condenser 35 or the second HX 33 and the condenser 35 can feed the nitrogen product portion 47 to the condenser 35.

[0094] The product portion 47 of the nitrogen-enriched steam 48 can be fed to the condenser 35 to be cooled via the third feed stream 42 fed to the condenser 35 to liquify the product portion 47 of the compressed nitrogen-enriched stream 48 for storage and subsequent use as a first product 16. The nitrogen content of the first product 16 can be between 100 vol% and 98 vol% or be within another pre-selected first product nitrogen concentration range.

[0095] The warmed third feed stream 44 output from the condenser 35 can be fed to the first column of the column assembly 15. The warmed third feed stream 44 can be fed to the firstcolumn at a location that is the same or lower than a location at which the substantially liquified or entirely liquified first feed stream 40 is fed to the first column.

[0096] In some embodiments, the warmed third feed stream 44 can be fed to the first column as a vapor or stream that is significantly vapor and not substantially liquified. The warmed second feed stream 43 can also be fed to the first column as a vapor or a stream that is significantly vapor and not substantially liquified. The warming via the second HX 32 and third HX 34 can sufficiently vaporize the second feed stream 41 so that the warmed second feed stream 43 is mostly vapor or entirely vapor in some embodiments. Also (or alternatively), the warming of the third feed stream 42 that can occur via the condenser 35 can sufficiently vaporize the third feed stream 42 so that the warmed third feed stream 44 output from the condenser 35 is mostly vapor or entirely vapor in some embodiments.

[0097] The first column 15 of the column assembly can include a reboiler R. The reboiler R can receive the non-product portion of the compressed nitrogen-enriched stream 48 that is cooled via the third HX 34 so that the heat for the reboiler R is provided via condensation of the nitrogen-enriched stream output from the third HX 34. The condensed nitrogen-enriched stream is output from the reboiler R as a reflux stream 27 that is fed to the top or adjacent to the top of the first column of the column assembly 15 for being fed to one or more rectifying sections adjacent the top of the first column or at the top of the first column.

[0098] The reflux stream 27 can be entirely liquid or substantially liquid. The heat from the reboiler R obtained via the condensation of the nitrogen-enriched stream 46 output from the third HX 34 can provide boil-up for the first column.

[0099] The first column of the column assembly can receive the first, second, and third feed streams 40, 43, and 44 to form the nitrogen-enriched stream 48 output from adjacent the top of the first column and an oxygen-enriched stream 45 output from adjacent the bottom of the firstcolumn. The oxygen-enriched stream 45 can be a liquid oxygen (LOX) stream or a crude LOX (CLOX) stream. The oxygen-enriched stream 45 can be fed to storage for subsequent use or distribution as an end product to end users as a second product 18 or can be fed as a second product 18 for use with another plant process. In some configurations, the oxygen content of the oxygen-enriched stream 45 output as a second product 18 can be between 100 vol% oxygen and 98 vol% oxygen or be within another suitable oxygen concentration range.

[0100] The nitrogen-enriched stream 48 output from the first column can be a vapor or a substantially vapor stream that is mostly nitrogen. In some implementations, the nitrogen content of the nitrogen-enriched stream 48 can be between 100 vol% nitrogen and 98 vol% nitrogen or within another suitable concentration range. As discussed above, the nitrogen- enriched stream 48 can undergo additional compression and cooling before a product portion 47 is split from the nitrogen-enriched stream 48 to undergo condensation via condenser 35 for forming first product 16. The non-production portion of the nitrogen-enriched stream 48 can be output from the third HX 34 as the nitrogen-enriched stream 46 for being fed to the reboiler R as discussed above as well.

[0101] In some embodiments, the first column of the column assembly can also output a third product stream 28 (shown in broken line in Figures 2 and 3). This third product stream 28 can be output from the first column as a substantially gaseous stream or as a gaseous stream that is output from the first column at a location between the locations at which the nitrogen-enriched stream 48 and the oxygen-enriched stream 45 are output from the first column. The third product stream 28 can be an argon-enriched stream in some embodiments. The third product stream 28 can be fed to another column (e.g. ArE 39 discussed above) to form a third product 20. The third product can be an argon-enriched or argon-rich product (e.g. the third product can include 100 vol% to 90 vol% argon, or be between 100 vol% argon and 95 vol% argon,etc.) in embodiments where the third product stream 28 is an argon-enriched stream, for example.

[0102] The first column can also output a waste stream 26w. The waste stream 26w can be a gaseous stream or a substantially gaseous stream that is vented to atmosphere or fed to a heat exchanger of a plant process for use as a cooling medium therein prior to being emitted as a waste gas or further processed by another plant element. The waste stream 26w can be a nitrogen-rich steam or an oxygen-rich stream depending on a location at which the waste stream is output from the first column. The location at which the waste stream 26w is withdrawn from the first column can be optimized based on a desired product split of liquid oxygen output as the oxygen-enriched stream 45 and gaseous nitrogen output as nitrogen- enriched stream 48 (e.g. a location of withdrawal near the bottom of the first column can result in waste stream 26w being oxygen-rich and a location of near the top of the first column can result in waste stream 26w being nitrogen-rich).

[0103] Figure 3 illustrates an embodiment of the separation processing apparatus 14 that can be arranged so that the compressor assembly is adapted for operation at ambient temperature instead of cooler operational temperatures (e.g. cryogenic operational temperatures). As can be appreciated from the embodiment of Figure 3, the separation processing apparatus 14 can include the same elements and streams as used in the exemplary embodiment of Figure 2 as well as another heat exchanger. This additional fourth HX 51 can be positioned and arranged to heat the nitrogen-enriched stream 48 output from the first column to an ambient temperature (e.g. a temperature in a range of -5°C to 40°C) so that the second compressor 31, second HX 32, third compressor 33, and third HX 34 can be arranged for operation at ambient temperatures. In such a configuration, the fourth HX 51 can also be positioned to cool the product portion 47 split from the nitrogen-enriched stream 48 before that product portion 47 isfed to the condenser 35. The fourth HX 51 can also be arranged to cool the nitrogen-enriched stream 46 output from the third HX 34 before that stream is fed to the reboiler R. These streams can be cooled in the fourth HX 51 by the nitrogen-enriched stream 48 output from the first column before that stream is fed to the second compressor 31 (e.g. the nitrogen-enriched stream 48 can be warmed by cooling the production portion 47 and nitrogen-enriched stream 46 output from the third HX).

[0104] Figure 3 illustrates the second feed stream 41 and warmed second feed stream 43 in broken line. In some embodiments, this second feed stream 41 may not be split off for feeding to heat exchangers of the compressor assembly (e.g. second HX 32 and third HX 34). Instead, other plant streams may be utilized to provide the cooling medium for cooling the portion of the compressed nitrogen-enriched product stream passed through those heat exchangers. It should be appreciated that such an option is also possible for the embodiment of Figure 2. In such embodiments that may not utilize this split second stream 41, the third feed stream 42 and the warmed third feed stream 44 can be considered a second feed stream 42 and second warmed feed stream 44.

[0105] As can be appreciated from Figure 3, at least a portion of the waste stream 26w can also be fed to the fourth HX 51 to function as an additional cooling medium for providing additional cooling of the product portion 47 and nitrogen-enriched stream 46 so that the waste stream 26w output from the fourth HX 51 is a warmed waste stream. In such embodiments, the warmed waste stream 26w output from the fourth HX 51 can be vented to atmosphere or fed to another plant process.

[0106] Whether a warmer-type operational configuration for the separation processing apparatus 14 (e.g. the embodiment shown in Figure 3, etc.) or a cooler-type operational configuration for the separation processing apparatus 14 (e.g. the embodiment of Figure 2) isselected for a particular implementation can be based on a number of design factors. For example, the cooler operational arrangement of Figure 2 can help minimize utilization of high tariff (or high cost) electricity utilization for the separation process. However, the cooler operation of the compressor assembly for that embodiment can incur increased losses of feed as waste in waste stream 26w as compared to the warmer compressor operational embodiment of Figure 3. Ambient temperature compression can require use of more electricity as compared to the cooler operational embodiment of Figure 2, but also permits a reduction in the loss of liquid feed. The trade-offs between these options can therefore be accounted for to select a design for an embodiment that best meets an operator’s needs and the anticipated duration of high tariff electricity or non-renewable power utilization time periods in a given day. Whether a warmer or cooler compressor assembly operation is selected for the separation processing apparatus 14 can depend on these as well as other factors. It should be appreciated, however, the separation processing apparatus 14 can be adapted to facilitate separation with a cooler or warmer compression assembly that may best meet an operator’s needs and preferences.

[0107] As can be appreciated from Figure 4, embodiments can be configured to utilize an automated process control system to help monitor and / or control operations of air separation apparatus or implementation of an embodiment of our process. In some configurations, the automated process control system can include a distributed control system (DCS) that utilizes a number of different control loops.

[0108] The automated process control system can include at least one controller that has a processor connected to a computer readable medium and at least one interface. The computer readable medium can be a non-transitory computer readable medium that can have code or at least one program stored thereon that defines a process that can be implemented when the processor runs the code or the program. The process that is defined can be defined forimplementation of an embodiment of our process, for example. The controller can be communicatively connected to at least one input device and at least one output device (e.g. a display). The input device can be a computer device that can be communicatively connected to the controller to provide user input for adjusting set points or other parameters. The input device can also, or alternatively, include a pointer device, at least one button, a keyboard, or a touch screen display. The controller can receive data from a plurality of sensors positioned in or adjacent different plant elements. The sensors can include temperature sensors, pressure sensors, level controllers, flow sensors, concentration detectors, concentration sensors, or other types of sensors or detectors.

[0109] It should be appreciated that modifications to the embodiments explicitly shown and discussed herein can be made to meet a particular set of design objectives or a particular set of design criteria. For instance, the arrangement of valves, piping, and other conduit elements (e.g. conduit connection mechanisms, tubing, seals, etc.) for interconnecting different units of the plant for fluid communication of the flows of fluid between different units can be arranged to meet a particular plant layout design that accounts for available area of the plant, sized equipment of the plant, and other design considerations. For instance, the size and configuration of any heat exchanger, conduits, expanders, pumps, or compressors can be modified to meet a particular set of design criteria. As another example, the flow rate, pressure, and temperature of the fluid passed through one or more heat exchangers as well as passed through other plant elements can vary to account for different plant design configurations and other design criteria. As yet another example, the number of plant units and how they are arranged can be adjusted to meet a particular set of design criteria. As yet another example, the material composition for the different structural components of the units of the plant andthe plant can be any type of suitable materials as may be needed to meet a particular set of design criteria.

[0110] As another example, it is contemplated that a particular feature described, either individually or as part of an embodiment, can be combined with other individually described features, or parts of other embodiments. The elements and acts of the various embodiments described herein can therefore be combined to provide further embodiments. Thus, while certain exemplary embodiments of the processes utilized to recover fluids (e.g. nitrogen, oxygen and / or argon, etc.) from air, gas separation plants configured to recover nitrogen, oxygen, and / or argon from at least one feed gas, air separation plants, air separation systems, and methods of making and using the same have been shown and described above, it is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the following claims.

Claims

CLAIMS1. A process for separation of a feed gas comprising oxygen and nitrogen, the process comprising: liquifying a feed gas to substantially liquify the feed gas to form a substantially liquified feed for a pre-selected time period via a liquefaction apparatus; feeding the substantially liquified feed from the liquefaction apparatus to at least one tank during the pre-selected time period, the at least one tank connected to a separation processing apparatus to feed the substantially liquified feed from the at least one tank to the separation processing apparatus to form at least a first product and a second product; and feeding the substantially liquified feed from the at least one tank to the separation processing apparatus continuously for a continuous time period that includes the pre-selected time period and additional time so the separation processing apparatus operates to form at least the first product and the second product.

2. The process of claim 1, wherein the feeding the substantially liquified feed from the at least one tank to the separation processing apparatus occurs while the liquefaction apparatus is not operating during a day or week as well as when the liquefaction apparatus is operated for liquifying the feed gas during the pre-selected time period within the day or week.

3. The process of claim 2, wherein the pre-selected time period is between 20 hours and 2 hours, 20 hours and 4 hours, between 20 hours and 6 hours, between 20 hours and 8 hours, between 20 hours and 12 hours, between 20 hours and 16 hours, between 20 hours and 18 hours, between 18 hours and 4 hours, between 18 hours and 6 hours, between 18 hours and 8 hours, between 18 hours and 16 hours or between 18 hours and 12 hours.

4. The process of claim 1, wherein the separation processing apparatus comprises a first column connected to a first tank of the at least one tank, the process also comprising: the first column receiving a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified; the first column receiving a second portion of the of the substantially liquified feed from the first tank after the second portion is at least partially vaporized via at least one heat exchanger of a compressor assembly arranged to cool a nitrogen- enriched stream output from the first column after compression of the nitrogen-enriched stream; and the first column receiving a third portion of the substantially liquified feed from the first tank after the third portion is at least partially vaporized via a condenser that is positioned to condense a product portion of the nitrogen-enriched stream output from the first column.

5. The process of claim 1, wherein the separation processing apparatus comprises a first column connected to a first tank of the at least one tank, the process also comprising: the first column receiving a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified; and the first column receiving a second portion of the substantially liquified feed from the first tank after the second portion is at least partially vaporized via a condenser that is positioned to condense a product portion of the nitrogen-enriched stream output from the first column.

6. The process of claim 5, wherein the second portion of the substantially liquified feed that is at least partially vaporized is fed to the first column at a location below a location at which the first portion of the substantially liquified feed is fed to the first column.

7. The process of claim 4, wherein the third portion of the substantially liquified feed that is at least partially vaporized is fed to the first column at a location below a location at which the second portion of the substantially liquified feed that is at least partially vaporized is fed to the first column.

8. The process of claim 1, wherein: the first product is a nitrogen-enriched liquid having a nitrogen content of between 100 volume percent (vol%) nitrogen and 98 vol% nitrogen; and the second product is an oxygen-enriched liquid having an oxygen content of between 100 vol% oxygen and 98 vol% oxygen.

9. The process of claim 8, wherein the at least one tank is connected to the separation processing apparatus to feed the substantially liquified feed to the separation processing apparatus to form the first product, the second product, and a third product, the third product being an argon-enriched fluid having an argon content of between 100 vol% argon and 80 vol% argon.

10. The process of claim 9, wherein the separation processing apparatus also comprises an argon enrichment column, the process comprising: outputting an argon enrichment stream from the first column for feeding to the argon enrichment column.

11. The process of claim 1, wherein the liquification apparatus and the at least one tank is sized relative to the separation processing apparatus so that a ratio of a feed rate of the substantially liquified feed fed to the at least one tank for the pre-selected time period to a feed rate at which the substantially liquified feed is fed from the at least one tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2.

12. The process of claim 1, wherein the substantially liquified feed is entirely liquid or is between 85 volume percent (vol%) liquid and 100 vol% liquid.

13. An air separation apparatus, comprising: a liquefaction apparatus positioned to liquify a feed gas to substantially liquify the feed gas to form a substantially liquified feed for a pre-selected time period; a first tank connected to the liquefaction apparatus to receive the substantially liquified feed from the liquefaction apparatus during the pre-selected time period; and a separation processing apparatus connected to the first tank to receive the substantially liquified feed from the first tank continuously for a continuous time period that includes the pre-selected time period and additional time so the separation processing apparatus is operable continuously throughout the continuous time period to form at least a first product and a second product.

14. The air separation apparatus of claim 13, comprising: a feed pump connected between the first tank and the separation processing apparatus.

15. The air separation apparatus of claim 13, wherein the separation processing apparatus comprises: a first column connected to the first tank, the first column positioned to receive a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified.

16. The air separation apparatus of claim 15, wherein the separation processing apparatus also comprises: a compressor connected to the first column to receive a nitrogen-enriched stream from the first column and at least one heat exchanger connected to the compressor to receive a compressed nitrogen-enriched stream from the compressor; the heat exchanger also connected to the first tank to receive a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and cool the compressed nitrogen-enriched stream; and the heat exchanger also connected to the first column to feed the vaporized second portion of the substantially liquified feed to the first column as a second feed stream.

17. The air separation apparatus of claim 16, wherein the separation processing apparatus also comprises: a condenser positioned to receive a product portion of the compressed nitrogen- enriched stream output from the compressor and a third portion of the substantially liquified feed from the first tank to vaporize the third portion of the substantially liquified feed and condense the product portion of the compressed nitrogen-enriched stream;the condenser also connected to the first column to feed the vaporized third portion of the substantially liquified feed to the first column as a third feed stream.

18. The air separation apparatus of claim 15, wherein the separation processing apparatus also comprises: a compressor connected to the first column to receive a nitrogen-enriched stream from the first column; a condenser positioned to receive a product portion of a compressed nitrogen-enriched stream output from the compressor and a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and condense the product portion of the compressed nitrogen-enriched stream; the condenser also connected to the first column to feed the vaporized second portion of the substantially liquified feed to the first column as a second feed stream.

19. The air separation apparatus of claim 13, wherein: the first product is a nitrogen-enriched liquid having a nitrogen content of between 100 volume percent (vol%) nitrogen and 98 vol% nitrogen; and the second product is an oxygen-enriched liquid having an oxygen content of between 100 vol% oxygen and 98 vol% oxygen; and wherein the substantially liquified feed is entirely liquid or is between 80 volume percent (vol%) liquid and 100 vol% liquid.

20. The air separation apparatus of claim 13, wherein the liquification apparatus and the first tank is sized relative to the separation processing apparatus so that a ratio of a feed rate of thesubstantially liquified feed outputtable from the liquefaction apparatus for feeding to the first tank for the pre-selected time period to a feed rate at which the substantially liquified feed is fed from the first tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2.

21. A process for separation of a feed gas comprising oxygen and nitrogen, the process comprising: liquifying a feed gas to substantially liquify the feed gas to form a substantially liquified feed; feeding the substantially liquified feed from the liquefaction apparatus to at least one tank connected to a separation processing apparatus to feed the substantially liquified feed from the at least one tank to the separation processing apparatus for separation of the substantially liquified feed.

22. The process of claim 21, comprising: feeding the substantially liquified feed from the at least one tank to the separation processing apparatus so the separation processing apparatus operates to form at least a first product.

23. The process of claim 21, wherein: the liquifying a feed gas to substantially liquify the feed gas to form a substantially liquified feed is performed for a pre-selected time period and the feeding of the substantially liquified feed from the liquefaction apparatus to the at least one tank occurs during the preselected time period; andwherein the feeding of the substantially liquified feed from the at least one tank to the separation processing apparatus occurs continuously for a continuous time period that includes the pre-selected time period and additional time so the separation processing apparatus operates to form at least a first product.

24. The process of claim 23, wherein the first product comprises liquid oxygen or liquid nitrogen.

25. The process of claim 23, wherein the separation processing apparatus operates to form at least a first product and a second product, the first product comprising liquid nitrogen and the second product comprising liquid oxygen.

26. The process of claim 23, wherein the pre-selected time period is between 2 hours and 20 hours and the continuous time period is at least 24 hours.

27. An air separation apparatus, comprising: a liquefaction apparatus positioned to liquify a feed gas to substantially liquify the feed gas to form a substantially liquified feed; and a first tank connected to the liquefaction apparatus to receive the substantially liquified feed from the liquefaction apparatus the first tank also connectable to a separation processing apparatus to feed the substantially liquified feed from the first tank to the separation processing apparatus to form at least a first product.

28. The air separation apparatus of claim 27, comprising: the separation processing apparatus, the separation processing apparatus configured to form the first product and at least one second product via separation of the substantially liquified feed; and wherein the liquefaction apparatus includes a liquefier, the liquefier connected to the first tank to feed the substantially liquified feed to the first tank.

29. The air separation apparatus of claim 27, comprising a feed pump connectable between the first tank and the separation processing apparatus; and wherein the separation processing apparatus also includes: a first column connected to the first tank, the first column positioned to receive a first portion of the substantially liquified feed from the first tank as a first feed stream that is substantially liquified; a compressor connected to the first column to receive a nitrogen-enriched stream from the first column and at least one heat exchanger connected to the compressor to receive a compressed nitrogen-enriched stream from the compressor; the heat exchanger also connected to the first tank to receive a second portion of the substantially liquified feed from the first tank to vaporize the second portion of the substantially liquified feed and cool the compressed nitrogen-enriched stream; and the heat exchanger also connected to the first column to feed the vaporized second portion of the substantially liquified feed to the first column as a second feed stream.

30. The air separation apparatus of claim 27, wherein the liquification apparatus and the first tank is sized relative to the separation processing apparatus so that a ratio of a feed rate of thesubstantially liquified feed outputtable from the liquefaction apparatus for feeding to the first tank for the pre-selected time period to a feed rate at which the substantially liquified feed is fed from the first tank to the separation processing apparatus for continuous operation of the separation processing apparatus is between 6:5 and 15:2.

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