WO2024119271A1

WO2024119271A1 - Liquefaction apparatus and method using a by-product of an adjacent air separation unit as a cooling medium

Info

Publication number: WO2024119271A1
Application number: PCT/CA2023/051621
Authority: WO
Inventors: Terry KEMP; Qun Mao
Original assignee: Foundation Renewable Carbon Inc
Current assignee: Foundation Renewable Carbon Inc
Priority date: 2022-12-08
Filing date: 2023-12-06
Publication date: 2024-06-13
Anticipated expiration: 2025-06-08

Abstract

A CO₂ liquefaction apparatus and method includes receiving CO₂ from a capture site. A first separator removes water and impurities. A compressor compresses the fluid. A cooler receives a cooling medium from an air separation unit via a heat exchanger. The cooler cools the compressed stream using the cooling medium. A second separator further removes water and impurities. The heat exchanger further cools the second separated stream using the cooling medium. An outlet delivers a liquefied stream of CO₂. A renewable natural gas (RNG) liquefaction apparatus and method includes receiving methane and CO₂ from a biogas treatment unit. A first heat exchanger cools the methane and CO₂ stream and condenses CO₂ therein. A separator separates liquid CO₂ from the cooled methane and CO₂ stream. A second heat exchanger liquefies the methane from the separator.

Description

LIQUEFACTION APPARATUS AND METHOD USING A BY-PRODUCT OF AN ADJACENT AIR SEPARATION UNIT AS A COOLING MEDIUM

BENEFIT OF EARLIER APPLICATIONS

[0001] This application claims priority from US provisional application 63/386,633, filed December 8, 2022.

TECHNICAL FIELD

[0002] The present invention relates to apparatus and methods for carbon capture and storage, and well renewable natural gas (RNG) liquefaction in general, and apparatus and methods for CO₂ and/or RNG liquefaction using repurposed cold energy waste by-products in particular.

BACKGROUND

[0003] Carbon dioxide (CO₂) is one of the main greenhouse gases responsible for global warming Carbon capture and storage or sequestration (CCS) is considered to be a promising technological option for the mitigation of CO₂ emissions, e.g., from industrial facilities that use fossil fuels as an energy source. Carbon capture and storage or sequestration, generally speaking, involves capturing CO₂ from its emitting sources, compressing and liquefying the captured CO₂, and transporting liquefied CO₂ (e.g., through pipelines and/or by truck), and storing the CO₂ in suitable geological formations, such as depleted oil and gas fields and/or saline aquifers, for permanent isolation from the atmosphere.

[0004] The captured CO₂ is often in gas phase, which generally needs to be liquefied and compressed to a dense phase for transportation. Conventional CO₂ liquefaction processes include a series of compression stages and a refrigeration cycle. Fig. 2 illustrates a conventional CO₂ liquefaction process and compression method. CO₂ is fed from a site 21 to a first separator 26, which separates condensed components such as water and impurities before the CO₂ is compressed in a compressor 27. After compression and cooling (e.g., at cooler 29), remaining water and impurities may be removed via a second separator 29. The CO₂ is liquefied in the heat exchanger 210 using a refrigerant, such as ammonia (NH₃) and/or propane. While the CO₂ is condensed, the ammonia may be evaporated in the heat exchanger. The evaporated ammonia is then compressed (e.g., at second compressor 27'), cooled (e.g., at second cooler29') and expanded (e.g., atexpander 30) in what is referred to as a refrigeration cycle. Alternately, CO₂ may be compressed to pressure in the range of 2,750-3,250 psi (e.g., approximately 3,000 psi) and converted from a gas to dense- phase liquid for transportation, e.g., via pipeline 32. [0005] These conventional CO2 liquefaction processes consume a considerable amount of energy with significant costs, and could result in additional CO₂ emissions, for example, if no electricity is generated via renewable energy available for the compression of the captured CO₂ and/or the refrigerants used in the refrigeration cycle. Accordingly, there is a demand for reducing the energy consumption of CO₂ liquefaction via process optimization.

[0006] CO₂ pipelines are essential for many carbon capture and storage or sequestration projects. After CO₂ is captured and liquefied, it is typically transported from a capture site to a storage site via a high pressure pipeline.

[0007] There are limited CO₂ pipeline networks available in the world. Existing CO₂ pipelines are built for relatively large industrial facilities to serve the largest of CO₂ emitters, such as fertilizer plants, refineries, power plants, etc. Few, if any, CO₂ pipelines accommodate the numerous small- and medium-sized, and even many large-sized, CO₂ emitters, such as remote mining sites, heavy oil in-situ thermal extraction fields, etc., which are located long distances from industrial zones. Accordingly, there is a demand for alternative options to transport CO₂ captured from such facilities, without the need for CO₂ transportation via pipeline.

[0008] Renewable natural gas (RNG), often called biomethane, is an upgraded biogas that has been cleaned and conditioned to remove non-methane elements. One such element can include CO₂, which is an impurity making up to 45% (mole) of the biogas. RNG is different from fossilbased natural gas because it comes from biogas. Biogas is produced from renewable biomass sources through biochemical processes via anaerobic digestion. There are various biomass sources, including landfills, livestock wastes, sludge from wastewater treatment plants, industrial and commercial waste, etc. Removal of CO₂, H₂S, O₂, N_2; and/or other impurities from the biogas provides pure (ormore concentrated) methane, which canbe injected and transported via existing natural gas pipelines and used as a substitute for natural gas, thereby reducing greenhouse gas (GHG) emissions.

[0009] Due to its low carbon intensity, the demand for, and production and use of, RNG has increased; however, there are disadvantages. Unlike fossil-based natural gas production at large scale, the production capacity of RNG is normally small, e.g., due to biogas sources being scattered and sparse. The installation and connection of pipelines for RNG transportation is expensive. Accordingly, there is a demand for further and lower cost RNG transportation, as an alternative and/or complementary to pipelines.

SUMMARY OF INVENTION

[0010] In accordance with a broad aspect of the invention, there is provided a CO₂ liquefaction apparatus, comprising: a first separator configured to receive an intake stream including CO₂, water, and impurities from a capture site, the first separator configured to remove water and impurities from the intake stream thereby creating a first separated stream; a compressor, coupled to the first separator to receive the first separated stream therefrom, the compressor configured to compress the fluid of the first separated stream, thereby creating a compressed stream; a cooler, coupled to the compressor to receive the compressed stream therefrom, the cooler configured to receive a cooling medium from an air separation unit via a heat exchanger, the cooler configured to cool the compressed stream using the cooling medium, thereby creating a cooled stream; a second separator, coupled to the cooler to receive the cooled stream therefrom, the second separator configured to remove water and impurities from the cooled stream, thereby creating a second separated stream; the heat exchanger being coupled to the second separator to receive the second separated stream therefrom, the heat exchanger being configured to further cool the second separated stream using the cooling medium, thereby creating a liquefied stream; and an outlet coupled to the heat exchanger for delivering the liquefied stream therefrom.

[0011] In accordance with another broad aspect of the invention, there is provided a CO₂ liquefaction method, comprising: receiving an intake stream including CO₂, water, and impurities from a capture site; removing at least a portion of water and impurities from the intake stream, thereby creating a first separated stream; compressing the first separated stream, thereby creating a compressed stream; cooling the compressed stream using a cooling medium from an air separation unit via a heat exchanger, thereby creating a cooled stream; separating at least a portion of any remainingwater and impurities from the cooled stream, thereby creating a second separated stream; condensing the second separated stream using the cooling medium, thereby creating a liquefied stream; and delivering the liquefied stream.

[0012] In accordance with yet another broad aspect of the invention, there is provided a CO₂ liquefaction method, comprising a cooler, coupled to a compressor to receive a compressed stream of CO₂ therefrom, the cooler configured to receive a cooling medium from an air separation unit via a heat exchanger, the cooler configured to cool the compressed stream using the cooling medium, thereby creating a cooled stream of CO₂.

[0013] In accordance with yet another broad aspect of the invention, there is provided a liquefaction apparatus, comprising: a first heat exchanger configured to receive an intake stream including CH₄ and CO₂; a second heat exchanger configured to receive a cooling medium and produce a cool stream therefrom; the first heat exchanger configured to receive the cool stream from the second heat exchanger permitting the first heat exchanger to cool the intake stream to produce a second stream; a separator configured to receive the second stream and separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and the second heat exchanger may be configured to receive the methane stream and liquefy the methane stream to produce a liquefied methane output stream.

[0014] In accordance with yet another broad aspect of the invention, there is provided a liquefaction method, comprising: receiving, at a first heat exchanger, an intake stream including CH₄ and CO₂; producing a cool stream using a second heat exchanger and delivering the cool stream to the first heat exchanger; cooling the intake stream at the first heat exchanger using the cool stream, thereby creating a second stream; flowing the second stream to a separator to separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and liquefying the methane stream using the second heat exchanger to produce a liquefied methane output stream.

[0015] It is to be understood that other aspects of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein various embodiments of the invention are shown and described by way of illustration. As will be realized, the invention is capable of other and different embodiments and its several details are capable of modification in various other respects, all within the present invention. Furthermore, the various embodiments described may be combined, mutatis mutandis, with other embodiments described herein. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Referring to the drawings, several aspects of the present invention are illustrated by way of example, and not by way of limitation, in detail in the figures, wherein: (a) Fig. 1 is a schematic diagram of an apparatus and method, according to one embodiment, of using cold nitrogen as a coolant to liquefy CO₂ and transport the liquefied CO₂ by truck from capture sites to sequestration sites;

(b) Fig. 2 is a schematic diagram of a typical conventional CO₂ liquefaction apparatus and method with a CO₂ pipeline for transportation of the liquefied and/or dense- phase CO₂, for comparison with the embodiment of Fig. 1 ; and

(c) Fig. 3 is a schematic diagram of a liquefaction apparatus and method, according to another embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

[0017] The detailed description set forth below in connection with the appended drawings is intended as a description of various embodiments of the present invention and is not intended to represent the only embodiments contemplated by the inventor. The detailed description includes specific details for the purpose of providing a comprehensive understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details.

[0018] An apparatus and method for CO₂ and/or RNG liquefaction is provided. The apparatus and method may use a cold energy medium, which may include, for example, liquid nitrogen, low temperature nitrogen gas, other cold liquids, and/or low temperature gases, to liquefy and/or cool CO₂ and/or RNG for further use, storage, and/or transport.

[0019] One possible advantage of the present invention is that it may use a cold energy medium, which may include, for example, liquid nitrogen, low temperature nitrogen gas, or other low temperature liquids or gases, such as oxygen, as cold energy to liquefy CO₂ and/or RNG. The liquefied CO₂ and/or RNG may then be transported, e.g., via a cryogenic tank, by truck or other vehicle, to a site with a demand for CO₂ for enhanced oil recovery, such as depleted oilfields, underground storage, or use applications such as greenhouse operations, and/or applications with a demand for RNG for use as fuel, among other applications.

[0020] Instead of using a conventional refrigeration cycle to generate cold energy for CO₂ and/or RNG or natural gas liquefaction, or high-pressure compression to a dense phase, the present apparatus and methods may use a cold energy medium, such as liquid nitrogen or low temperature nitrogen gas, etc., as a coolant to liquefy CO2 and/or RNG, e.g., using a heat exchanger. Furthermore, the liquefied CO₂ and/or RNG may be transported in a cooled chamber, which may be a cryogenic tank, and transported, e.g., by truck, from a CO₂ capture site and/or RNG production site to a second site, such as a storage site and/or a use site. Examples of CO₂ storage sites include depleted oil fields, and suitable underground geologic formations for permanent storage. Examples of CO₂ use sites include those suitable for the application of enhanced oil recovery methods. Examples of RNG use sites include liquid RNG/LNG fueling stations and power plants in remote mining sites and communities.

[0021] Cold energy may be generated by an air separation unit (ASU), which produces oxygen with cold nitrogen as a by-product. Such cold energy may otherwise be wasted. Trucks fitted with a cryogenic tank may be used to transport liquid nitrogen from the ASU to the CO₂ or RNG liquefaction apparatus. Alternatively, a pipeline may be used to deliver the low temperature nitrogen from the air separation unit to the CO₂ liquefaction unit, e.g., if the ASU and liquefaction apparatus are in close proximity.

[0022] For CO₂ liquefaction, nitrogen from the heat exchanger may be sent to a cooler to cool the CO₂ from the CO₂ compressor. Heated nitrogen fromthe cooler may be releasedto the atmosphere. In such an embodiment, less (and possibly no) cooling water is required as a cooling medium, which is typically required in conventional CO₂ liquefaction apparatus and methods.

[0023] An apparatus for CO₂ liquefaction is provided. With reference to Fig. 1, in one embodiment, the apparatus includes capturing and/or receiving CO₂ from a capture site 1, and liquefying the CO₂ using a liquefaction apparatus 2. The liquefaction apparatus may include using a cooling medium, e.g., cold nitrogen, which may come from an air separation unit 3. The air separation unit may be of the environment in which the apparatus 2 operates. The liquefied CO₂ may be transported, e.g., by a truck 4 to a site 5 for use, storage and/or sequestration. The method may include capturing CO₂, liquefying CO₂, and transporting the liquefied CO₂.

[0024] The cooling medium may include cold nitrogen, which may be liquid nitrogen or low temperature nitrogen. Such coolingmedium may be a by-product of an air separation unit 3 (ASU), which may be adjacent to the liquefaction apparatus. In other words, the by-product of the air separation unit (or other source of the cooling medium) may be put to use rather than wasted. In some embodiments, the cooling medium may be delivered in a chamber (e.g., a cryogenic tank) and transported by a vehicle (e.g., a truck), which may be preferredifthe coolingmedium is liquid, and/or through pipe, which may be preferred if the cooling medium is in gas phase.

[0025] In one embodiment, an apparatus and method for CO₂ liquefaction is provided. In one embodiment, a CO₂ liquefaction apparatus 2 may include a first separator 6, which receives a stream including CO₂, and possibly water and impurities, from a CO₂ capture site 1 , and removes at least some of the water and impurities, if any, from the stream; a CO₂ compressor 7, for compressing the CO₂ from the first separator; a CO₂ cooler 8, which may use a cooling medium from a heat exchanger 10 to cool the CO₂ from the CO₂ compressor; a second separator 9 for removing some or all of the remaining water and impurities (if any) in the CO₂ stream; and the heat exchanger 10, which may use the cooling medium from a cooling medium source (such as an air separation unit 3) to liquefy the CO₂ from the second separator.

[0026] Heat exchanger 10 may receive the cooling medium (e.g., cold nitrogen) to liquefy CO₂. The CO₂ cooler 8 may receive the cooling medium from the heat exchanger 10 to cool the CO₂ from the CO₂ compressor 7. While the CO₂ is cooled in the cooler 8, the cooling medium (in the illustrated example, nitrogen) is heated and may be discharged to the atmosphere. Heat exchanger 10 may cool the CO₂ from the second separator 9 in multiple stages, which may permit more efficient use of the cold energy carried by the cold nitrogen from air separation unit 3.

[0027] Cooler 8 may cool the CO₂ from the CO₂ compressor in multiple stages, which may permit efficient use of cold energy carried by the cold nitrogen from the heat exchanger. In such an embodiment, the multiple-stage CO₂ cooler may include inter-stage separators for removing water and impurities (if any) in the CO₂ stream.

[0028] It is to be appreciated that the present apparatus and method for CO₂ liquefaction do not necessarily include refrigerationcycles requiredin the prior art to provide cold energy to condense CO₂. Instead, the described apparatus and method may use one or more cooling media that are byproducts of one or more cooling media sources, e.g., from an adjacent air separation unit (as source) with a by-product of nitrogen (as cooling medium). Since no refrigerant compression is required in the present CO₂ liquefaction apparatus and method, the energy consumption may be less than that of conventional CO₂ liquefaction apparatus and methods.

[0029] In one embodiment, the present apparatus and method do not require a cooling water system. There is no need for a refrigerant cooler that uses cooling water as a cooling medium for the cooling of refrigerant, such as ammonia and/or propane, which is typically required in conventional means of the prior art. In addition, unlike CO₂ coolers of conventional CO₂ liquefaction apparatus and methods that use cooling water to cool CO₂ from their CO₂ compressors, the present apparatus and method use a cooling medium (in the illustrated example, nitrogen) from the heat exchanger to cool CO₂ from the CO₂ compressor.

[0030] In one embodiment, the present apparatus and method for carbon capture and storage or sequestration use cold energy from a by-product of air separation, e.g., waste liquid nitrogen or low temperature nitrogen. In such an embodiment, there is no need for a refrigeration cycle, which is required for providing cold energy for CO₂ liquefaction, and no needfora cooling water system, high pressure CO₂ pump, or CO₂ pipeline. The present apparatus and method, which may also be a carbon capture and storage or sequestration apparatus and method, is especially suitable for industrial CO₂ emitters that are located long distances from CO₂ pipeline networks where there is no CO₂ pipeline available or convenient to transport the CO₂ captured at such facilities.

[0031] In one embodiment, a renewable natural gas (RNG) and/or CO₂ liquefaction apparatus includes a first heat exchanger 14, a second heat exchanger 16, and a separator 15.

[0032] The first heat exchanger receives methane and CO₂ from a biogas source 11, e.g., via a biogas treatment unit 12. The second heat exchanger receives a stream 16 of a cooling medium, e.g., liquid nitrogen. The first heat exchanger may be coupled to the second heat exchanger such that the first heat exchanger may receive a stream of cool nitrogen from the second heat exchanger.

[0033] The biogas treatment unit may remove H₂S, water, and/or other impurities from a stream of biogas from source 11 , thereby creating a biogas intake stream 12a for delivery to the first heat exchanger. The biogas intake stream 12a may include methane and CO₂.

[0034] The first heat exchanger may cool the biogas intake stream and condense the CO₂ therein, thereby creating a second stream 14a of biogas including CO₂ and methane . The second stream 14a may be a two-phase stream, i.e., the second stream may include a liquid and a gas, e.g., liquid CO₂ and methane gas. Separator 15 may receive the second stream from the first heat exchanger. The separator may remove the liquid CO₂ from the second stream, thereby creating a liquid CO₂ output stream 15a, and a methane stream 15b. The liquid CO₂ output stream may be delivered to a container and/or vehicle for transportation and/or storage. The methane stream may be received by the second heat exchanger. [0035] The separator may remove liquid CO2 from the cooled methane and CO2 of stream 14a. The second heat exchanger 16 may liquefy the methane received from the separator via stream 15b. Liquid nitrogen may be used as cooling medium for one or more of the heat exchangers. The liquefied streams including liquid RNGand liquid CO2 may be deliveredto a cryogenic tank and/or transported, e.g., by truck, to a liquid RNG end user, liquid CO₂ storage site, and/or elsewhere.

[0036] It is to be appreciated that the present apparatus and method for RNG liquefaction do not necessarily include refrigeration cycles requiredin the prior art to provide cold energy to condense renewable natural gas (RNG) or fossil-based natural gas. Instead, the described apparatus and method may use one or more cooling media that are by-products of one or more cooling media sources, e.g., from an adjacent air separation unit (as source) with a by-product of nitrogen (as cooling medium). Since no refrigerant compression is required in the present liquefaction apparatus and method, the energy consumption may be less than that of conventional natural gas liquefaction apparatus and methods.

[0037] It is to be appreciated that the present apparatus and method for RNG liquefaction provide a way of removing CO₂ from biogas, using cold nitrogen as a cooling medium to condense the CO₂ in the biogas stream, in addition to or as an alternative for other technologies, such as membrane filtration, pressure swing adsorption (PSA), chemical solvent scrubbing, etc.

Clauses

[0038] Clause 1. A CO₂ liquefaction apparatus, comprising: a first separator configured to receive an intake stream including CO2, water, and impurities from a capture site, the first separator configured to remove water and impurities from the intake stream thereby creating a first separated stream; a compressor, coupled to the first separator to receive the first separated stream therefrom, the compressor configured to compress the fluid of the first separated stream, thereby creating a compressed stream; a cooler, coupled to the compressor to receive the compressed stream therefrom, the cooler configured to receive a coolingmedium from an air separation unit via a heat exchanger, the cooler configuredto cool the compressed streamusingthe coolingmedium, thereby creating a cooled stream; a second separator, coupled to the cooler to receive the cooled stream therefrom, the second separator configured to remove water and impurities from the cooled stream, thereby creating a second separated stream; the heat exchanger being coupled to the second separator to receive the second separated stream therefrom, the heat exchanger being configured to further cool the second separated stream using the cooling medium, thereby creating a liquefied stream; and an outlet coupled to the heat exchanger for delivering the liquefied stream therefrom.

[0039] Clause 2. The apparatus of any one or more of clauses 1-9, wherein the heat exchanger conducts cooling in multiple stages.

[0040] Clause 3. The apparatus of any one or more of clauses 1-9, wherein the cooler conducts cooling in multiple stages.

[0041] Clause 4. The apparatus of any one or more of clauses 1-9, wherein the cooler further comprises inter-stage separatorsfor removing water and impurities from the compressed stream.

[0042] Clause 5. The apparatus of any one or more of clauses 1-9, wherein the liquefied stream is delivered to a cryogenic tank and transported by truck to a storage site.

[0043] Clause 6. A CO₂ liquefaction method, comprising: receiving an intake stream including CO₂, water, and impurities from a capture site; removing at least a portion of water and impurities from the intake stream, thereby creating a first separated stream; compressing the first separated stream, thereby creating a compressed stream; cooling the compressed stream using a cooling medium from an air separation unit via a heat exchanger, thereby creating a cooled stream; separating at least a portion of any remaining water and impurities from the cooled stream, thereby creating a second separated stream; condensing the second separated stream using the cooling medium, thereby creating a liquefied stream; and delivering the liquefied stream.

[0044] Clause 7. A CO₂ liquefaction method, comprising a cooler, coupled to a compressor to receive a compressed stream of CO₂ therefrom, the cooler configured to receive a cooling medium from an air separation unit via a heat exchanger, the cooler configured to cool the compressed stream using the cooling medium, thereby creating a cooled stream of CO₂.

[0045] Clause 8. A liquefaction apparatus, comprising: a first heat exchanger configured to receive an intake stream including CH₄ and CO₂; a second heat exchanger configured to receive a cooling medium and produce a cool stream therefrom; the first heat exchanger configured to receive the cool stream from the second heat exchanger permitting the first heat exchanger to cool the intake stream to produce a second stream; a separator configured to receive the second stream and separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and the second heat exchanger may be configured to receive the methane stream and liquefy the methane stream to produce a liquefied methane output stream.

[0046] Clause 9. A liquefaction method, comprising: receiving, at a first heat exchanger, an intake stream including CH₄ and CO₂; producing a cool stream using a second heat exchanger and delivering the cool stream to the first heat exchanger; cooling the intake stream at the first heat exchanger using the cool stream, thereby creating a second stream; flowing the second stream to a separator to separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and liquefying the methane stream using the second heat exchanger to produce a liquefied methane output stream.

[0047] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to those embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein, but is to be accorded the full scope consistent with the claims, wherein reference to an element in the singular, such as by use of the article "a" or "an" is not intended to mean "one and only one" unless specifically so stated, but rather "one or more". All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the elements of the claims. Moreover, nothing disclosed hereinis intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 USC 112, sixth paragraph, unless the element is expressly recited using the phrase "means for" or "step for".

Claims

1. A CO₂ liquefaction apparatus, comprising: a first separator configured to receive an intake stream including CO₂, water, and impurities from a capture site, the first separator configured to remove water and impurities from the intake stream thereby creating a first separated stream; a compressor, coupled to the first separator to receive the first separated stream therefrom, the compressor configured to compress the fluid of the first separated stream, thereby creating a compressed stream; a cooler, coupled to the compressor to receive the compressed stream therefrom, the cooler configured to receive a cooling medium from an air separation unit via a heat exchanger, the cooler configured to cool the compressed stream using the cooling medium, thereby creating a cooled stream; a second separator, coupled to the cooler to receive the cooled stream therefrom, the second separator configured to remove water and impurities from the cooled stream, thereby creating a second separated stream; the heat exchanger being coupled to the second separator to receive the second separated stream therefrom, the heat exchanger being configured to further cool the second separated stream using the cooling medium, thereby creating a liquefied stream; and an outlet coupled to the heat exchanger for delivering the liquefied stream therefrom.

2. The apparatus of claim 1 , wherein the heat exchanger conducts cooling in multiple stages.

3. The apparatus of claim 1, wherein the cooler conducts cooling in multiple stages.

4. The apparatus of claim 3, wherein the cooler further comprises inter-stage separators for removing water and impurities from the compressed stream.

5. The apparatus of claim 1 , wherein the liquefied stream is delivered to a cryogenic tank and transported by truck to a storage site. A C0₂ liquefaction method, comprising: receiving an intake stream including CO₂, water, and impurities from a capture site; removing at least a portion of water and impurities from the intake stream, thereby creating a first separated stream; compressing the first separated stream, thereby creating a compressed stream; cooling the compressed stream using a cooling medium from an air separation unit via a heat exchanger, thereby creating a cooled stream; separating at least a portion of any remaining water and impurities from the cooled stream, thereby creating a second separated stream; condensing the second separated stream using the cooling medium, thereby creating a liquefied stream; and delivering the liquefied stream. A CO₂ liquefaction method, comprising a cooler, coupled to a compressor to receive a compressed stream of CO₂ therefrom, the cooler configured to receive a cooling medium from an air separation unit via a heat exchanger, the cooler configured to cool the compressed stream using the cooling medium, thereby creating a cooled stream of CO₂. A liquefaction apparatus, comprising: a first heat exchanger configured to receive an intake stream including CH₄ and CO₂; a second heat exchanger configured to receive a cooling medium and produce a cool stream therefrom; the first heat exchanger configured to receive the cool stream from the second heat exchanger permitting the first heat exchanger to cool the intake stream to produce a second stream; a separator configured to receive the second stream and separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and the second heat exchanger may be configured to receive the methane stream and liquefy the methane stream to produce a liquefied methane output stream.faction method, comprising: receiving, at a first heat exchanger, an intake stream including CH₄ and CO2; producing a cool stream using a second heat exchanger and delivering the cool stream to the first heat exchanger; cooling the intake stream at the first heat exchanger using the cool stream, thereby creating a second stream; flowing the second stream to a separator to separate CO₂ therefrom, thereby creating a liquefied CO₂ output stream and a methane stream; and liquefying the methane stream using the second heat exchanger to produce a liquefied methane output stream.