FIELD OF THE INVENTION

The present innovation relates to processes utilized to recover fluids (e.g. oxygen, argon and nitrogen) from air, gas separation plants configured to recover nitrogen, argon and/or oxygen from at least one feed gas, air separation plants, air separation systems, systems utilizing multiple columns to recover nitrogen, argon, and oxygen fluids, and methods of making and using the same.

BACKGROUND OF THE INVENTION

Electronic chip manufacturers have traditionally required nitrogen gas for their facilities. Air separation processing was utilized to provide nitrogen gas for such facilities. Examples of systems that were developed in conjunction with air separation processing include U.S. Pat. Nos. 4,022,030 and 4,822,395 and U.S. Pat. App. Pub. Nos. 2019/0331417, 2019/0331418, and 2019/0331419.

Chip manufacturing facilities often utilized air separation processes designed to produce predominantly nitrogen gas flows as well as waste oxygen. The waste oxygen contained most of the oxygen and argon in the incoming air, plus some unrecovered nitrogen. A typical waste oxygen output flow composition from such facilities is 65% oxygen, 3% argon, and 32% nitrogen.

More recently, some manufacturers may require the air separation plant in their facility to supply high purity argon as well as nitrogen. Typically, such systems are designed so that the oxygen purity of the oxygen waste output flow must be greater than 99.5% to 99.9% oxygen, zero nitrogen, and the balance argon.

SUMMARY

We have determined that some air separation processes designed to provide high-purity nitrogen and argon fluids for use by a manufacturing facility (e.g. a chip manufacturing facility or other facility that may have such needs, etc.) can often produce large quantities of high-purity oxygen, which has little or no value to the facility operator. We have determined that such air separation processing can be designed to reduce the power needed to form nitrogen and argon fluid flows. In some arrangements, we have determined that it is possible to improve the argon recovery without increasing power consumption or providing a reduction in overall power consumption, which can improve processing efficiency and also make the process more environmentally friendly.

In some embodiments, a process for separation of a feed gas comprising oxygen, nitrogen, and argon can include compressing a feed gas via a compression system of a separation system having a first column and a second column. The first column can be a high pressure (HP) column operating at a pressure that is higher than the second column. The second column can be a low pressure (LP) column operating at a pressure that is lower than the first column. The process can also include feeding the compressed feed gas to a first heat exchanger to cool the compressed feed gas, feeding at least a first portion of the compressed and cooled feed gas to the HP column to produce a first HP nitrogen-enriched vapor and a first HP oxygen-enriched stream, condensing at least a portion of the first HP nitrogen-enriched vapor via a first reboiler-condenser to form an HP condensate so that a first portion of the HP condensate is recyclable to the HP column and a second portion of the HP condensate is feedable to the LP column, and outputting a first nitrogen-rich vapor stream, a first nitrogen-enriched waste stream, a first LP oxygen-rich liquid steam, and a first argon-enriched vapor stream from the LP column. The first LP oxygen-rich liquid can have an oxygen content of at least 98 mol % oxygen. The process can also include feeding the first argon-enriched vapor stream to an argon column to form a first argon-rich vapor stream that is feedable to a second reboiler-condenser and an argon-depleted liquid stream that is feedable to the LP column, at least partially condensing the first argon-rich vapor stream output from the argon column via the second reboiler-condenser, and mixing the first nitrogen-enriched waste stream output from the LP column with the first LP oxygen-rich liquid stream output from the LP column for forming a mixed nitrogen-oxygen fluid stream to feed to the second reboiler-condenser to provide at least a portion of a refrigeration duty of the second reboiler-condenser for the at least partially condensing of the first argon-rich vapor stream.

In some embodiments, the argon-enriched vapor stream can be 5-25 volume % (vol. %) argon and the first argon-rich vapor stream can be 100-95 vol. % argon. For instance, the first argon-rich vapor stream can be 0-4 vol. % oxygen, 0-0.5 vol. % nitrogen, and the balance argon (e.g. 100-95.5 vol. % argon).

In some embodiments, the first HP nitrogen-enriched vapor stream can include 100-99 vol. % nitrogen and the HP oxygen-enriched stream can include 30-40 vol. % oxygen, and 1-3 vol. % argon, and the balance nitrogen (e.g. 69-57 vol. % nitrogen).

In some embodiments, the first nitrogen-rich vapor stream can include 99-100 vol. % nitrogen, the first nitrogen-enriched waste stream can include 95-99 vol. % nitrogen, and the first LP oxygen-rich liquid steam has an oxygen content of (i) at least 98 mol % oxygen, (ii) greater than or equal to 99.5 mol % oxygen, (iii) 98-100 mol % oxygen, or (iv) 98-99.5 mol % oxygen.

Embodiments of the process can also include other processing steps. For example, embodiments of the process can include splitting the compressed feed gas into the first portion and a second portion and feeding the second portion of the compressed feed gas to an expander for reducing its pressure for feeding it to the LP column after the second portion of the compressed feed gas is passed through the first heat exchanger. As another example, the process can include passing the first nitrogen-rich vapor stream and the second portion of the HP condensate through a subcooler so that the second portion of the HP condensate is cooled via the subcooler before the second portion of the HP condensate is fed to the LP column. The first nitrogen-rich vapor stream can be a top nitrogen-rich vapor stream that is output from the LP column.

In some embodiments, the feed gas can be air (e.g. air from the atmosphere external to a plant). The compression system can include at least one compressor having one or more stages for compression of the feed gas. The compression system can also include other elements. For example, the compression system can also include a purification unit that removes at least one of carbon dioxide and water from the feed gas after the feed gas is compressed.

In some embodiments, the first nitrogen-enriched waste stream can be a first nitrogen-enriched liquid waste stream. In some of these embodiments, the mixed nitrogen-oxygen fluid stream can be a mixture of the first nitrogen-enriched liquid waste stream and the first LP oxygen-rich liquid stream.

In other embodiments, the first nitrogen-enriched waste stream can be a first nitrogen-enriched vapor waste stream. In some of these embodiments, the mixed nitrogen-oxygen fluid stream can be a mixture of the first nitrogen-enriched vapor waste stream and the first LP oxygen-rich liquid stream.

In some embodiments, the mixing can include mixing the first nitrogen-enriched vapor waste stream with the first LP oxygen-rich liquid stream to form a mixture and subsequently feeding the mixture to a phase separator to form the mixed nitrogen-oxygen fluid stream. This mixed nitrogen-oxygen fluid stream can be a liquid.

In other embodiments, the mixing can be performed via a mixing column such that the first nitrogen-enriched vapor waste stream and the first LP oxygen-rich liquid stream are fed to the mixing column to perform the mixing to form the mixed nitrogen-oxygen fluid stream. The mixed nitrogen-oxygen fluid stream in such embodiments can be a liquid.

More than one nitrogen-enriched waste stream can be utilized in the process. For example, a second nitrogen-enriched waste stream can be output from the LP column. For such embodiments, the first nitrogen-enriched waste stream can a first nitrogen-enriched vapor waste stream and the second nitrogen-enriched waste stream can be a first nitrogen-enriched liquid waste stream. Alternatively, the first nitrogen-enriched waste stream can a first nitrogen-enriched liquid waste stream and the second nitrogen-enriched waste stream can be a first nitrogen-enriched vapor waste stream. For such embodiments, the mixing can be performed via a mixing column so that the first nitrogen-enriched liquid waste stream, the first nitrogen-enriched vapor waste stream and the first LP oxygen-rich liquid stream are fed to the mixing column to perform the mixing to form the mixed nitrogen-oxygen fluid stream. When such a mixing column arrangement is utilized, the first nitrogen-enriched liquid waste stream can be fed adjacent to or at a bottom of the mixing column and the first LP oxygen-rich liquid can be fed adjacent a top of the mixing column. The first nitrogen-enriched vapor stream can be fed adjacent to the bottom of the mixing column. Other embodiments can utilize other mixing column arrangements.

In some embodiments of the process, at least the portion of the refrigeration duty of the second reboiler-condenser for the at least partially condensing of the first argon-rich vapor stream can be an entirety of the refrigeration duty for the at least partially condensing of the first argon-rich vapor stream. It should also be appreciated that the at least partially condensing of the first argon-rich vapor stream can be a complete condensing of the first argon-rich vapor so that a second reboiler-condenser output stream of the second reboiler-condenser is an argon-rich liquid. In other embodiments, the at least partially condensing of the first argon-rich vapor stream may not be a complete condensing (e.g. can condense a pre-selected fraction of the vapor that is less than 100% of the vapor, can condense a substantial portion of the vapor, can condense almost all of the vapor, etc.). For partial condensing of the argon-rich vapor stream, some of the argon-rich output can be a fluid that includes liquid and vapor (or gas).

Embodiments of a separation system are also provided. Embodiments of the system can be configured as an air separation system in some embodiments. The air separation system can be designed for incorporation into a standalone plant or can be configured as a plant for utilization in conjunction with other facilities connected to the plant. Embodiments of the separation system can include a compression system, a first heat exchanger, a first column and a second column. The first column can be a high pressure (HP) column operating at a pressure that is higher than the second column. The second column can be a low pressure (LP) column operating at a pressure that is lower than the first column. The system can also include a first reboiler-condenser and a second reboiler-condenser. The compression system, the first heat exchanger, and the HP column can be positioned and arranged so that a feed gas is compressible via the compression system before the compressed feed gas is fed to the first heat exchanger and at least a first portion of the compressed feed gas is feedable to the HP column after passing through the first heat exchanger. The HP column can be positioned and configured to produce a first HP nitrogen-enriched vapor stream and a first HP oxygen-enriched stream. The first reboiler-condenser can be positioned to receive at least a portion of the first HP nitrogen-enriched vapor to form an HP condensate so that a first portion of the HP condensate is recyclable to the HP column and a second portion of the HP condensate is feedable to the LP column. The LP column can be positioned and configured to output a first nitrogen-rich vapor stream, a first nitrogen-enriched waste stream, a first LP oxygen-rich liquid steam, and a first argon-enriched vapor stream. The first LP oxygen-rich liquid stream can have an oxygen content of at least 98 mol % oxygen. The argon column can be positioned and configured to receive the first argon-enriched vapor stream output from the LP column to form a first argon-rich vapor stream that is feedable to the second reboiler-condenser and an argon-depleted liquid stream that is feedable to the LP column. The second reboiler-condenser can be positioned and configured to at least partially condense the first argon-rich vapor stream. The system can be configured such that the first nitrogen-enriched waste stream output from the LP column is mixable with the first LP oxygen-rich stream output from the LP column for forming a mixed nitrogen-oxygen fluid stream to feed to the second reboiler-condenser to provide at least a portion of a refrigeration duty of the second reboiler-condenser for the at least partially condensing of the first argon-rich vapor stream.

In some embodiments, the HP column, LP column, and argon column can be structured as distillation columns or separation columns. Each column can have multiple stages and utilize packing or not utilize packing. The first and second reboiler-condensers can include one or more heat exchangers to facilitate partial vaporization and condensation of different streams or facilitate complete vaporization and compete condensation of different streams. In some embodiments, the second reboiler-condenser can include multiple heat exchanger units that each process a respective portion of the first argon-rich vapor stream for at least partial condensing of that stream. The heat exchanger units can operate in parallel. In some embodiments utilizing this type of second reboiler-condenser, a first heat exchanger of the multiple heat exchangers can receive the mixed nitrogen-oxygen fluid stream and a second heat exchanger of the multiple heat exchangers can receive a portion of the first HP oxygen-enriched stream. In other embodiments, a first heat exchanger of the multiple heat exchangers and a second heat exchanger of the multiple heat exchangers can receive the mixed nitrogen-oxygen fluid stream and optionally also receive a portion of the first HP oxygen-enriched stream.

Some embodiments of the system can include a mixing column that is positioned and configured to receive the first LP oxygen-rich liquid stream output from the LP column and the first nitrogen-enriched waste stream output from the LP column to form the mixed nitrogen-oxygen fluid stream. Other embodiments of the system can include a mixing column that is positioned and configured to receive the first LP oxygen-rich stream output from the LP column, the first nitrogen-enriched waste stream output from the LP column, and a second nitrogen-enriched waste stream output from the LP column to form the mixed nitrogen-oxygen fluid stream. In such embodiments, the first nitrogen-enriched waste stream can be a first nitrogen-enriched liquid waste stream and the second nitrogen-enriched waste stream can be a first nitrogen-enriched vapor waste stream.

In some embodiments, the system can include a phase separator positioned and configured to receive the mixed nitrogen-oxygen fluid stream so that a liquid portion of the mixed nitrogen-oxygen fluid stream is fed to the second reboiler-condenser.

Embodiments of the system can also include other elements. For example, the system can also include a subcooler positioned and configured so that the second portion of the HP condensate passes through the subcooler before the second portion of the HP condensate is fed to the LP column and the first nitrogen-rich vapor stream passes through the subcooler. The second portion of the HP condensate can be cooled via the subcooler and the first nitrogen-rich vapor stream can be heated via the subcooler. The first nitrogen-rich vapor stream can be a top nitrogen-rich vapor stream output from the LP column.

The system can also include an expander. The system can be configured such that the compressed feed gas is split into multiple flow portions that include the first portion of the compressed feed gas that is feedable to the HP column and a second portion of the compressed feed gas. The expander can be positioned and configured to receive the second portion of the compressed feed gas to reduce the pressure of the second flow portion of the compressed feed gas for feeding it to the LP column.

In other embodiments, there may not be such splitting of the compressed feed gas. For instance, the first portion of the compressed feed gas can be an entirety of the compressed feed gas. As noted above, the feed gas is air (e.g. air obtained from air external to the system or the plant including the system, etc.).

It should be appreciated that different streams of fluid can include vapor, liquid, or a combination of vapor and liquid. Fluid streams that include vapor can include vapor, or gas.

It should be appreciated that 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 tubing, piping, valves, and other conduit elements. The system can also utilize sensors 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, etc.) can be connected to different conduits or system elements.

Other elements can also be included in embodiments of the system. For instance, one or more pumps, vessels, or other units can also be utilized in embodiments of the system. It should be appreciated that embodiments of the system can be structured and configured to utilize at least one embodiment of the process.

Other details, objects, and advantages of our processes utilized to recover fluids (e.g. oxygen, argon and nitrogen) from air, gas separation plants configured to recover nitrogen, argon and/or oxygen from at least one feed gas, air separation plants, air separation systems, systems utilizing multiple columns to recover nitrogen, argon, and oxygen fluids, 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.

