Integrating a steam cracking device and a brid ammonia

Abstract

A method and system that integrates a steam cracking unit with a blue ammonia unit such that a methane-rich gas stream and / or a hydrogen-rich gas stream is directed from the steam cracking unit to the blue ammonia unit while a hydrogen-containing gas stream is directed from the blue ammonia unit to the steam cracking unit.

Description

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 515,293, filed July 24, 2023, and U.S. Provisional Application No. 63 / 581,581, filed September 8, 2023, both of which are incorporated by reference herein in their entireties. TECHNICAL FIELD

[0002] The present invention relates to a system and method for integrating a steam cracking unit and a blue ammonia unit to reduce CO2 emissions. BACKGROUND

[0003] Olefin production typically involves steam cracking - a process that can be extremely energy intensive and contribute significantly to global CO2 emissions. A major source of direct CO2 emissions is the cracking furnace, where fuel gas is burned to provide the heat required for the net process heating to meet the heat of cracking reaction (endothermic reaction) and to use the waste heat to generate steam.

[0004] The fuel gas used in a steam cracking unit can contain up to 80 mol% - 85 mol% H2 in an ethane cracking unit, or as low as 10 mol% - 15 mol% in a liquid cracking unit, with the remainder being primarily methane. The combustion of hydrogen gas has no associated CO2 emissions, while the combustion of methane produces approximately 230 kg CO2 per gigacaloric burn load.

[0005] In a typical steam cracking unit, combustion air enters the furnace without being preheated. With cold combustion air, a significant portion of the combustion duty is required to heat the combustion air to the combustion temperature, with associated CO2 emissions. This results in a relatively large flue gas stream, which is then used to provide the net heat for feed preheating and superheated high pressure (SHP) steam generation. SUMMARY

[0006] Exemplary embodiments of integrating a steam cracking unit with a blue ammonia unit to reduce CO2 emissions can significantly avoid one or more problems due to limitations and disadvantages of the prior art.

[0007] Additional features and advantages of the present invention will be set forth in the description below, and in part will be apparent from the description, or can be learned by practice of the present invention. The objectives and other advantages of the present invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings.

[0008] In an example, a system can include a steam cracking unit including a cracking furnace; a blue ammonia unit in fluid communication with the steam cracking unit, the blue ammonia unit configured to generate a hydrogen-containing stream; a first conduit configured to direct the hydrogen-containing stream to the steam cracking unit for use as fuel.

[0009] In an example, the blue ammonia unit can include a hydrogen generation system configured to generate a hydrogen-rich ammonia synthesis gas stream, where the hydrogen-containing stream can include the hydrogen-rich ammonia synthesis gas stream.

[0010] In an example, the blue ammonia unit can include an ammonia synthesis gas purification system configured to generate a purified ammonia synthesis gas stream, where the hydrogen-containing stream includes the purified ammonia synthesis gas stream.

[0011] In an example, the steam cracking unit can include a recovery system configured to receive a stream of effluent cracked gas from the cracking furnace and separate at least a hydrogen-rich stream and a methane-rich stream from the stream of effluent cracked gas.

[0012] In an example, the system can include a second conduit configured to direct the methane-rich stream from the steam cracking unit to the blue ammonia unit for use as fuel, feed, or both.

[0013] In an example, the system can include a gas compressor configured to pressurize at least a portion of the methane-rich stream prior to the methane-rich stream reaching the blue ammonia unit.

[0014] In an example, the system can include a gas expander configured to expand the hydrogen-containing stream prior to the hydrogen-containing stream reaching the steam cracking unit.

[0015] In an example, the gas compressor can be powered by energy recovered from the gas expander.

[0016] In an example, the system can include a heater configured to heat the hydrogen-containing stream prior to the hydrogen-containing stream reaching the gas expander.

[0017] In an example, the steam cracking unit can include a recycle line configured to direct the hydrogen-rich stream from the recovery system to the cracking furnace for use as fuel.

[0018] In an example, the blue ammonia unit can include a hydrogen generation system configured to generate a hydrogen-rich ammonia synthesis gas stream, where the hydrogen-containing stream can include the hydrogen-rich ammonia synthesis gas stream; and a fourth conduit configured to direct at least a portion of the hydrogen-rich ammonia synthesis gas stream to the steam cracking unit for combination with the hydrogen-rich stream.

[0019] In an example, the blue ammonia unit can include an ammonia synthesis gas purification system configured to generate a purified ammonia synthesis gas stream, where the hydrogen-containing stream includes the purified ammonia synthesis gas stream; and a fourth conduit configured to direct at least a portion of the purified ammonia synthesis gas stream to the steam cracking unit for combination with the hydrogen-rich stream.

[0020] In an example, the system can include a third conduit configured to direct at least a portion of the hydrogen-rich gas stream from the steam cracking unit to the blue ammonia unit.

[0021] In an example, the blue ammonia unit can include an ammonia synthesis gas purification system, wherein the entire hydrogen-rich gas stream can be directed to the ammonia synthesis gas purification system.

[0022] In an example, the system can include a fourth conduit configured to direct the outflow purified ammonia synthesis gas from the ammonia synthesis gas purification system to a cracking furnace of the steam cracking unit for use as fuel.

[0023] In an example, a method is described that can include generating a hydrogen-containing gas stream in a blue ammonia unit; and directing the hydrogen-containing gas stream to a steam cracking unit as fuel.

[0024] In an example, the method can include recovering a methane-rich gas stream in a steam cracking process; and directing the methane-rich gas stream to the blue ammonia unit as feed, fuel, or both.

[0025] In an example, the method can include recovering a hydrogen-rich gas stream from an outflow cracked gas of a cracking furnace of the steam cracking unit.

[0026] In an example, the method can include directing the recovered hydrogen-rich gas stream to the cracking furnace of the steam cracking unit for use as fuel.

[0027] In an example, the method can include supplementing the hydrogen-rich gas stream with a hydrogen-containing gas stream from the blue ammonia unit.

[0028] In an example, the hydrogen-containing gas stream can include at least a portion of a hydrogen-rich ammonia synthesis gas stream generated by a hydrogen generation system of the blue ammonia unit.

[0029] In an example, the hydrogen-containing gas stream can include at least a portion of a purified ammonia synthesis gas stream generated by an ammonia synthesis gas purification system of the blue ammonia unit.

[0030] In an example, the method can include directing the hydrogen-rich gas stream to a purification stage of the blue ammonia unit, and directing at least a portion of the purified ammonia synthesis gas stream generated by the ammonia synthesis gas purification system to a cracking furnace of the steam cracking unit for use as fuel.

[0031] In an example, the method can include compressing at least a portion of the methane-rich gas stream via a gas compressor before the methane-rich gas stream reaches the blue ammonia unit; expanding the hydrogen-containing gas stream generated in the blue ammonia unit via a gas expander before the hydrogen-containing gas stream reaches the steam cracking unit; and powering the gas compressor with energy recovered from the gas expander.

[0032] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are intended to provide further explanation of the application as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0033] The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the principles of the application.

[0034] In the drawings:

[0035] Figures 1A to 1C is an example schematic of an integrated method and system of a steam cracking unit and a blue ammonia unit.

[0036] Figures 2A to 2C is an example diagram illustrating different implementations of a blue ammonia unit that can be integrated with a steam cracking unit as described above.

[0037] Figure 3A and Figure 3B is an example diagram illustrating a cracking furnace system of a steam cracking unit.

[0038] Figure 4 is an example illustrating a recovery system of a steam cracking unit.

[0039] Figure 5 is an example illustrating an example implementation for integrating a steam cracking unit with a blue ammonia unit. DETAILED DESCRIPTION

[0040] In examples, a method and system of integrating a steam cracking unit with an ammonia unit is described herein. In examples, the ammonia unit is a blue ammonia unit. For purposes of this disclosure, the term "blue ammonia unit" is used to refer to a unit (or facility or system) that produces ammonia from natural gas while also capturing and storing carbon dioxide (CO2) emissions generated during the production process. In examples, the disclosed method and system can achieve low or zero CO2 emissions by integrating a steam cracking unit with a blue ammonia unit.

[0041] In examples, a steam cracking unit can include an olefins unit configured to produce one or more olefins through thermal cracking of a hydrocarbon feedstock, such as, for example, naphtha, ethane, propane, or butane, in the presence of steam. In examples, a high-temperature, high-pressure process can break down larger hydrocarbon molecules into smaller molecules, primarily ethylene and propylene. In examples, the olefins can be used for various industrial applications.

[0042] Recycling of hydrogen from effluent gas of the cracking furnace of the steam cracking unit is possible, but typically limited in its purity level that it can generate. Hydrogen can be recovered in the steam cracking unit via a crude separation of the effluent products. In an example, the separation can separate olefins from a hydrogen and methane effluent. In an example, further separation can result in a hydrogen rich stream and a methane rich stream. In an example, the separation of hydrogen and methane can be performed in a cold box to produce a high pressure hydrogen rich stream with a purity of about 90 mol% - 95 mol% and a low pressure methane rich stream that is typically used as fuel gas. A portion of the hydrogen rich stream can be injected into the methane rich stream to achieve the necessary temperature driving force in the cold box to enable the cooling and separation. Thus, the recovery of usable hydrogen can be limited to about 80% - 85%.

[0043] While this system can reduce carbon emissions, it can not be sufficient to achieve the desired results.

[0044] To address some of these issues, disclosed herein is a method and system in which the external hydrogen rich gas generated in the blue ammonia unit can be used as fuel in the steam cracking unit. In an example, the method and system can integrate the steam cracking unit with the blue ammonia unit. In an example, the integration can be configured such that the tail gas from the steam cracking unit can be used as feed to the blue ammonia unit. In an example, the integration can be configured such that the blue ammonia unit can be employed to achieve a higher hydrogen concentration of the hydrogen rich stream separated from the effluent gas of the cracking furnace of the steam cracking unit. In an example, the integration can be configured such that supplemental hydrogen is input to the cracking plant in the form of ammonia synthesis gas to supplement and / or replace the hydrogen rich stream.

[0045] In an example, the ammonia synthesis gas can comprise about 75 mol% hydrogen and 25 mol% nitrogen. In an example, the method and system as described can reduce carbon emissions in the steam cracking plant. In an example, the carbon emissions can be eliminated completely or almost completely.

[0046] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood by one of ordinary skill in the art to which this application belongs. All patents, patent applications, published applications and publications, websites and other published materials referred to throughout the entire disclosure herein, unless otherwise indicated, are incorporated by reference in their entirety. If a term is used herein that is not defined, the term should be given its ordinary meaning as understood by one of ordinary skill in the art. In the case of a reference to a URL or other such identifier or address, it is understood that such identifiers can change and information on the internet can change from time to time, but equivalent information can be found by searching the internet. Reference thereto evidences the availability and public dissemination of such information.

[0047] As used herein, the singular forms “a”, “an” and “the” can include plural referents unless the context clearly dictates otherwise.

[0048] As used herein, the terms first, second, third, etc. can describe various elements, components, regions, layers and / or sections and should not be limited by these terms. These terms can be used merely to distinguish one element, component, region, layer or section from another region, layer or section. The terms such as “first”, “second” and other numerical terms are used herein do not imply order or sequence unless the context clearly dictates. Thus, a first element, component, region, layer or section discussed below can be termed a second element, component, region, layer or section without departing from the teachings of example embodiments.

[0049] As used herein, ranges and amounts can be expressed as “about” a particular value or range. About also includes the exact amount. Thus, about 5% means about 5% and not 5%. The term about means within typical experimental error for the desired application or purpose.

[0050] As used herein, “and / or” includes any and all combinations of one or more of the associated listed items.

[0051] As used herein, “combination” refers to any association between two items or between more than two items. The association can be spatial or refer to using two or more items for a common purpose.

[0052] As used herein, “comprise”, “comprising”, “include”, “including” and “has” should be interpreted as “including but not limited to”.

[0053] As used herein, “optional” or “optionally” means that the subsequently described event or circumstance can or can not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. For example, an optional component of a system means that the component can or can not be present in the system.

[0054] As used herein, “substantially” means “for the most part but not entirely as specified”.

[0055] As used herein, “negligible amount” refers to an amount present at a concentration of 1 mol% or less.

[0056] In an example, integration of the steam cracking unit and the blue ammonia unit can include transfer of one or more gas streams between the two units. In an example, a methane- rich gas stream produced in the steam cracking unit can be directed to the ammonia unit to be used as a feed, a fuel, or both. In an example, a hydrogen-rich gas stream produced in the steam cracking unit can be supplemented by a hydrogen-rich ammonia synthesis gas from the blue ammonia unit. In an example, a hydrogen-rich gas stream produced in the steam cracking unit can be directed to the blue ammonia unit for purification. In an example, a purified ammonia synthesis gas stream can be directed from the blue ammonia unit to the steam cracking unit to be used as a fuel.

[0057] For purposes of this disclosure, a “purified ammonia synthesis gas stream” refers to a gas stream that contains substantially hydrogen gas or a mixture of hydrogen gas and nitrogen gas. In an example, a purified ammonia synthesis gas stream will contain no more than negligible amounts of substances other than hydrogen gas or a mixture of hydrogen gas and nitrogen gas. In an example, a purified ammonia synthesis gas stream can contain pure hydrogen (i.e., > 99.5 mol% hydrogen gas), or a mixture of hydrogen gas and nitrogen gas (where the mixture constitutes at least 99 mol% of the stream).

[0058] Figures 1A to 1C A schematic of an integrated method and system 100 of a steam cracking unit 110 and a blue ammonia unit 130 is provided. The integrated method and system 100 can include a steam cracking unit 110 in fluid communication with a blue ammonia unit 130. Figures 1A to 1C The same reference numbers are used to refer to the same components and streams. In an example, the integrated method and system 100 can include a steam cracking unit 110 in fluid communication with a blue ammonia unit 130.

[0059] As illustrated, the steam cracking unit 110 can include a cracking furnace 112 and a recovery system 114. A hydrocarbon feed 116, which can be a gas or a liquid, can be fed to the cracking furnace 112. The hydrocarbon feed 116 can crack in the presence of high-temperature steam as it passes through one or more reactor tubes in the cracking furnace 112. The effluent cracked gas 118 from the cracking furnace 112 can include hydrogen gas, methane, and one or more olefins. In an example, the effluent cracked gas 118 can be directed to the recovery system 114 of the steam cracking unit 110. In an example, the recovery system 114 can separate a rich-olefin stream (not shown), a methane-rich gas stream 120, and a hydrogen-rich stream 122 from the effluent cracked gas 118. In an example, the hydrogen-rich stream 122 can be recycled via a recycle line 108 configured to direct the hydrogen-rich stream 122 to the cracking furnace 112 to be used as a fuel. Further details of the steam cracking unit 110 are described later with reference to FIG. 3 and FIG. 4. Figure 4 Provided.

[0060] As Figures 1A to 1CAs illustrated, the blue ammonia unit 130 can include a hydrogen generation system 132, an ammonia synthesis gas purification system 134, and an ammonia synthesis system 136. In an example, the hydrogen generation system 132 can receive a natural gas feed 138, such as methane to be reacted with steam (not shown), to produce a hydrogen-rich ammonia synthesis gas stream 144. In an example, an oxygen source, such as an air stream 140a, can be fed to the hydrogen generation system 132 to provide oxygen to facilitate the generation of hydrogen and to provide nitrogen that can be used in ammonia synthesis. In an example, the air stream 140a can further include nitrogen. In an example, nitrogen can be supplied at the ammonia synthesis gas purification system 134 via stream 140b, and / or at the ammonia synthesis system 136 via stream 140c in addition to and / or in lieu of stream 140a.

[0061] In an example, as illustrated, the methane-rich gas stream 120 from the steam cracking unit 110 can be directed to the hydrogen generation system 132. In an example, the methane-rich gas stream 120 can be used as a fuel to provide heat for hydrogen generation. In an example, the methane-rich gas stream 120 can be used as a feed in the same manner as the hydrocarbon feed 138 to provide hydrocarbons from which hydrogen can be recovered. In an example, the methane-rich gas stream 120 can be used as both a fuel and a feed to the hydrogen generation system 132. In an example, a portion of the methane-rich gas stream 120 can be used as a fuel and another portion of the methane-rich gas stream 120 can be used as a feed. In an example, at least a portion of the methane-rich gas stream 120 can be used as the sole feed to the hydrogen generation system 132, i.e., replacing the natural gas feed 138.

[0062] In an example, the steam cracking unit 110 can be controlled such that at least a portion of the methane-rich gas stream 120 fed to the hydrogen generation system 132 to be used as a source of hydrogen for hydrogen generation can have a flow rate based on the amount of hydrogen generated by the hydrogen generation system 132 of the blue ammonia unit 130. In an example, the amount of methane-rich gas in the methane-rich gas stream 120 can be fed to the hydrogen generation system 132 for hydrogen generation at a ratio of about 1 kg of methane-rich gas per about 1.5 kg to about 1.6 kg of purified ammonia synthesis gas stream 148 output from the ammonia synthesis gas purification system 134 of the blue ammonia unit 130.

[0063] In an example, the flow of the methane-rich gas stream 120 can be controlled using one or more controllers. In an example, the flow of the methane-rich gas stream 120 to the hydrogen generation system 132 for hydrogen production can be controlled via one or more valves. In an example, a portion of the methane-rich gas stream 120 can be diverted for use as fuel for the hydrogen generation system 132. In an example, the flow of the methane-rich gas stream 120 to the hydrogen generation system 132 for hydrogen production can be controlled by varying the amount of the methane-rich gas stream 120 diverted for use as fuel for the hydrogen generation system 132. In an example, varying the flow of the feed to the hydrogen generation system 132 can control the amount of the methane-rich gas stream 120 diverted for use as fuel for the hydrogen generation system 132. In an example, a portion of the methane-rich gas stream 120 can be extracted (not shown) and stored or otherwise disposed of. In an example, the flow rate of the methane-rich gas stream 120 to be fed to the hydrogen generation system 132 for hydrogen production and / or to be used as fuel for the hydrogen generation system 132 can be controlled by varying the amount extracted from the methane-rich gas stream 120. Any combination of these controls, which can be actuated by one or more controllers and valve systems, can be implemented to control the flow of the methane-rich gas stream 120 or a portion thereof to the hydrogen generation system 132 for hydrogen production, to be used as a feed to the hydrogen generation system 132, or both.

[0064] In an example, the carbon dioxide gas stream 142 generated by the hydrogen generation system 132 can be captured via a carbon capture system (not shown).

[0065] In an example, as Figure 1A illustrated, a portion 146 of the hydrogen-rich ammonia synthesis gas stream 144 from the hydrogen generation system 132 can be directed to the steam cracking unit 110 to supplement the hydrogen-rich stream 122 when it is fed to the cracking furnace 112 as fuel. In an example, supplementing the hydrogen-rich stream 122 can result in lower carbon emissions in the flue gas of the cracking furnace 112.

[0066] In an example, as Figures 1A to 1C illustrated, the remaining portion of the hydrogen-rich ammonia synthesis gas stream 144 can be fed to the ammonia synthesis gas purification system 134, which can remove at least a portion of any hydrocarbons or other extraneous gases not used for ammonia production to result in a purified ammonia synthesis gas stream 148. In an example, the purified ammonia synthesis gas stream 148 can be directed to the ammonia synthesis system 136 for ammonia production, which results in an ammonia stream 150.

[0067] It is noted that in examples where nitrogen is introduced into the blue ammonia unit only at stream 140c, the purified ammonia synthesis gas stream 148 can include a high purity hydrogen stream having a hydrogen concentration of at least 99.5 mol%. Conversely, where nitrogen is introduced through streams 140a and / or 140b, the purified ammonia synthesis gas stream 148 can include a mixture of hydrogen and nitrogen. In examples, the purified ammonia synthesis gas stream 148 can include a mixture of about > 74 mol% hydrogen and about > 24 mol% nitrogen, and can have only negligible amounts of other gases.

[0068] In examples, as Figure 1B illustrated, a portion 152 of the purified ammonia synthesis gas stream 148 from the ammonia synthesis gas purification system 134 can be directed to the steam cracking unit 110 to supplement the hydrogen-rich stream 122 as fuel feed to the cracking furnace 112. This can be done as an alternative or in addition to directing a portion 146 of the hydrogen-rich ammonia synthesis gas stream 144 to the steam cracking unit 110 as described with reference to Figure 1A In examples, by directing portion 152 instead of portion 146, the hydrogen concentration in the hydrogen-rich stream 122 that is directed to the cracking furnace 112 for use as fuel can be increased. In examples, as Figure 1B also shown, at least a portion 124 of the hydrogen-rich stream 122 from the recovery system 114 can optionally be directed to the ammonia synthesis gas purification system 134 to further remove hydrocarbons such as methane from the stream. In this way, the hydrogen concentration of the hydrogen-rich stream 122 that is ultimately sent to the cracking furnace 112 for use as fuel can include an even higher hydrogen concentration. In examples, a higher hydrogen concentration means a lower hydrocarbon or methane concentration, and thus lower carbon emissions in the flue gas of the cracking furnace 112.

[0069] In examples, the remaining portion of the purified ammonia synthesis gas stream 148 can be directed to the ammonia synthesis system 136 to produce an ammonia stream 150 as described earlier.

[0070] In examples, as Figure 1C illustrated, all of the hydrogen-rich stream 122 can be sent to the ammonia synthesis gas purification system 134. In this example, the portion 152 of the purified ammonia synthesis gas stream 148 that is directed to the steam cracking unit 110 can be the only fuel sent to the cracking furnace 112. In examples, the portion 152 of the purified ammonia synthesis gas stream 148 can include a high purity hydrogen stream (i.e., a hydrogen concentration of at least 99.5 mol%) or a mixture containing hydrogen and nitrogen (where the hydrogen concentration is about > 74 mol% and the nitrogen concentration is about > 24 mol%), and can contain only trace amounts of other gases. In examples, either option would limit, if not eliminate, the methane or other hydrocarbons from the fuel stream to the cracking furnace 112, thereby limiting or eliminating carbon emissions from the flue gas of the cracking furnace 112.

[0071] As described with reference to Figure 1B In examples, a remaining portion of the purified ammonia synthesis gas stream 148 can be directed to the ammonia synthesis system 136 to produce the ammonia stream 150 as described earlier.

[0072] In examples, with the above integration scheme, the blue ammonia unit 130 can be utilized to supplement or further purify the hydrogen fuel that is fed to the cracking furnace 112, thereby reducing or eliminating carbon emissions. In examples, with the above integration scheme, the methane rich gas stream 120 recovered by the recovery system 114 can be utilized. In examples, the integration can allow for the utilization of the carbon capture system of the blue ammonia system to reduce or eliminate carbon emissions. In examples, the integration as described can be achieved without interfering with ammonia production in the blue ammonia unit 130.

[0073] In examples, as Figures 1A to 1C illustrated, the integrated method and system 100 can include one or more gas expanders 154 and / or gas compressors 156. In examples, the pressure of one or more hydrogen containing gas streams from the blue ammonia unit 130 to the steam cracking unit 110 (i.e., the portion 146 of the hydrogen rich ammonia synthesis gas stream 144 and / or the portion 152 of the purified ammonia synthesis gas stream 148) can be reduced based on the steam cracking plant fuel gas back pressure. In examples, the integrated system and method 100 can include one or more gas expanders 154 to reduce the pressure of these streams. In examples, one type of gas expander 154 suitable for this use can be a turbo expander. In examples, the gas expanders 154, such as turbo expanders, can be configured to recover energy, such as electricity, when expanding the hydrogen containing gas streams.

[0074] In examples, preheating of one or more hydrogen containing gas streams from the blue ammonia unit 130 to the steam cracking unit 110 can optionally be performed. In examples, the integrated system or method 100 can include one or more heaters 158. In examples, the heaters 158 can be electric heaters, heat exchangers, or any other suitable heating device. In examples, the one or more heaters 158 can be arranged to preheat the hydrogen containing gas streams from the blue ammonia unit prior to being depressurized by the one or more gas expanders 154. In this way, in examples, the recovery of electricity can be maximized. In examples, the target preheat amount can be set to achieve expander outlet temperatures close to ambient temperature.

[0075] In an example, the methane-rich gas stream 120 directed from the steam cracking unit 110 to the blue ammonia unit 130 can be at a relatively low pressure. In an example, the pressure of the methane-rich gas stream 120 can be about 3 barg to 8 barg. In an example, the integrated system and method 100 can include one or more gas compressors 156. In an example, the one or more gas compressors 156 can be arranged and configured to compress at least a portion of the methane-rich gas stream 120 to a desired blue ammonia unit feed gas pressure.

[0076] In an example, power for the gas compressors 156 can come from a source other than the gas expanders 154. In an example, one or more gas compressors 156 used to compress the methane-rich gas stream can be powered by energy recovered from one or more gas expanders 154. In an example, a gas expander 154 can be employed to drive a gas compressor 156 in a direct coupled arrangement. In an example, a gas expander 154 can be employed to generate power by expanding a gas stream, and then apply that power to offset power required to drive methane-rich gas compressors 156 and / or to power other equipment and / or to store for later use.

[0077] In an example, the implementation of the integration can depend on the nature of the blue ammonia unit. As described below, different types of blue ammonia units can be used in the integration. Although the implementation can vary based on the nature of the blue ammonia unit, the integration as described is equally applicable to different types of blue ammonia units.

[0078] It is noted that the hydrogen-rich stream generated by the cracking unit, the hydrogen-rich ammonia synthesis gas stream from the blue ammonia unit, and the purified ammonia synthesis gas stream, and all portions thereof, as referenced throughout this disclosure, can generally be collectively referred to as hydrogen gas streams. The differences between these hydrogen gas streams can be in the concentration of hydrogen gas present in each stream, and / or the presence and / or lack of one or more additional substances in each stream, as described throughout this disclosure.

[0079] Ammonia synthesis techniques

[0080] Type 1 :

[0081] In an example, the blue ammonia unit 130 described below with reference to Figures 2A to 2C may be implemented for ammonia production. The ammonia synthesis processes described below are merely illustrative to demonstrate the application of the integration across different variations of blue ammonia units. Any blue ammonia unit can be integrated with a steam cracking unit in the same or similar manner as described herein.

[0082] In an example, the blue ammonia unit 130 exemplified for integration with a steam cracking unit can include a steam-methane reformer (SMR) system as the hydrogen generation system 132.

[0083] Steam-methane reforming (SMR) is a widely used industrial method for producing hydrogen (H2) from the reaction of natural gas (e.g., methane, CH4) with steam (water vapor). In this example, the SMR process produces hydrogen (H2) and carbon monoxide (CO) through a series of chemical reactions. In this example, the reaction can be carried out under pressure at a high temperature, for example, between about 700°C and 1,000°C. In this example, heating for the SMR process can be provided electrically and / or by burning fuel.

[0084] For example, in the initial step, hydrocarbons or methane can react with water molecules in steam to produce carbon monoxide and hydrogen, as illustrated in equation (1):

[0085] CH4 + H2O → CO + 3H2(1)

[0086] In the example, hydrogen produced by the SMR method can then be combined with nitrogen for ammonia synthesis.

[0087] In the example, such as Figure 2A As shown, the SMR of the blue ammonia unit 200 may include a primary reformer 210 and a secondary reformer 212. In this example, the two reformers 210 and 212 may be connected in series. In this example, the primary reformer 210 and the secondary reformer 212 can be used to generate hydrogen from methane and steam.

[0088] In this example, the primary reformer 210 may include feed 206. In this example, feed 206 may include natural gas feed. In this example, feed 206 may include one or more hydrocarbons. In this example, feed 206 may include methane. In this example, feed 206 may be supplied at least partially by a methane-rich gas stream 120 from the steam cracking unit. In this example, at least a portion of the methane-rich gas stream from the steam cracking unit constitutes all of the feed 206 to the primary reformer 210. In this example, feed 206 may be supplied at least partially by a separate source.

[0089] In the example, in the primary reformer 210, methane from feed 206 can react with steam to produce carbon monoxide and hydrogen. In the example, steam can be provided to the primary reformer 210 via steam feed 208. In the example, heat for the reaction can be provided to the primary reformer 210 via an electric heater, burning fuel, or any combination thereof. In the example, heat in the primary reformer 210 can be provided at least partially by burning fuel 214. In the example, fuel 214 can include hydrocarbons, such as methane. In the example, fuel 214 can be supplied at least partially by a methane-rich gas stream 120 from the steam cracking unit. In the example, at least a portion of the methane-rich gas stream from the steam cracking unit is the sole fuel 214 used for the primary reformer 210. In the example, fuel 214 can be supplied from a separate source.

[0090] In an example, flue gas 211 generated by combustion of a methane or other natural gas containing fuel in the primary reformer 210 can include carbon dioxide. In an example, where a hydrocarbon containing fuel is used to generate heat in the primary reformer 210, a carbon capture system 216 can be implemented to avoid or minimize carbon emissions. In an example, the fuel used to generate heat in the primary reformer 210 can not contain methane or other hydrocarbons, and thus there can be no carbon dioxide in the flue gas. In an example, where there is little to no carbon dioxide in the flue gas generated by combustion of the fuel in the reformer, there can be no carbon capture system 216.

[0091] In an example, the effluent of the primary reformer 210 can be fed to a secondary reformer 212 of the SMR process. In an example, a compressed air stream 218 can be introduced into the secondary reformer 212 to burn a portion of the natural gas or hydrocarbons in the feed to generate heat for the reaction. In an example, the compressed air stream 218 can include regular air as a source of nitrogen and oxygen for the secondary reforming of the methane. In such an example, none of the steps of the process produce a pure hydrogen stream. In an example, the compressed air stream 218 can be the only source of nitrogen. In an example, during this combustion, oxygen (O2) can be consumed, while stoichiometric nitrogen (N2) can remain for use in the downstream generation of ammonia. In an example, the generation of hydrogen continues in the secondary reformer 212.

[0092] In an example, the effluent of the secondary reformer 212 can include a syngas mixture 220. In an example, the syngas mixture 220 can include hydrogen, carbon monoxide, carbon dioxide, unreacted steam, unreacted methane or other hydrocarbons, and nitrogen.

[0093] In an example, the blue ammonia unit 200 can include a water gas shift reactor (WGS) 222. In an example, the WGS 222 can be a two-stage water gas shift reactor. In an example, the WGS 222 can be positioned after the secondary reformer 212. In an example, the syngas mixture 220 from the secondary reformer 212 can be fed to the WGS 222. In an example, the syngas mixture 220 can be cooled before being sent to the WGS 222. In an example, in the WGS 222, the syngas mixture 220 can undergo further reactions to increase the hydrogen yield.

[0094] In an example, the carbon monoxide produced in the SMR and contained in the syngas mixture 220 can be further reacted with steam in the WGS to produce additional hydrogen and carbon dioxide, as exemplified by equation (2):

[0095] CO + H2O → CO2 + H2(2)

[0096] WGS effluent 224 from WGS 222 may include a modified syngas mixture. In an example, WGS effluent 224 may include a higher hydrogen concentration than syngas mixture 220.

[0097] In this example, WGS effluent 224 may be fed into a CO2 separator 228, which is connected to a carbon capture system 226 to which the separated CO2 may be sent. In this example, any carbon capture technology known in the art may be used for carbon capture system 226 and optionally carbon capture system 216. In this example, carbon capture systems 226 and 216 may be the same or different. In this example, CO2 separator 228 may include any suitable system capable of sequestering CO2 from WGS effluent 224. In this example, CO2 separator 228 may include a monoethanolamine washing method. In this example, CO2 separator 228 may include a celexol method, in which polyethylene glycol dimethyl ether (DEPG) may be used to selectively remove carbon dioxide from WGS effluent 224. These are merely examples, and other systems may also be included. In this example, CO2 separator 228 may include a methanation method. In this example, a methanation method may convert any remaining carbon monoxide into methane. This avoids poisoning downstream ammonia synthesis and / or provides methane for recycling.

[0098] The effluent from CO2 separator 228 may include a hydrogen-rich ammonia synthesis gas stream 230. In an example, the hydrogen-rich ammonia synthesis gas stream 230 may include hydrogen, nitrogen, and methane. In an example, hydrogen may be the main component of the hydrogen-rich ammonia synthesis gas stream 230. In an example, methane gas may be present only in small amounts. In an example, the hydrogen-rich ammonia synthesis gas stream 230 may include greater than 64 mol% hydrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230 may include greater than 32 mol% nitrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230 may include less than 3 mol% methane gas or other hydrocarbons. In an example, the hydrogen-rich ammonia synthesis gas stream 230 may include 65 mol% hydrogen, 33 mol% nitrogen, and 2 mol% methane gas.

[0099] In the example, such as Figure 2A As shown, a portion 232a of the hydrogen-rich ammonia syngas stream 230 can be directed to a steam cracking unit to supplement the hydrogen-rich stream recovered by the steam cracking unit's recovery system for use as fuel in the cracking furnace. In this example, the remaining portion of the hydrogen-rich ammonia syngas stream 230 can be directed to a syngas purification system 234. In this example, a portion 232a of the hydrogen-rich ammonia syngas stream 230 is not directed to the steam cracking unit, and all of the hydrogen-rich ammonia syngas stream 230 is sent to the syngas purification system 234.

[0100] In an example, a portion 232b of the hydrogen-rich ammonia synthesis gas stream 230 can be used as fuel for the SMR process. In an example, the portion 232b of the hydrogen-rich ammonia synthesis gas stream 230 can be combined with and / or used in place of the fuel 214. In an example, the portion 232b of the hydrogen-rich ammonia synthesis gas stream 230 can be combined with at least a portion of the methane-rich gas from the integrated steam cracking unit to be used as fuel in place of and / or in addition to the fuel 214.

[0101] In an example, the blue ammonia unit 130 can include an ammonia synthesis gas purification system 134 implemented as a synthesis gas purification system 234.

[0102] In an example, the synthesis gas purification system 234 can include a purifier. In an example, the purifier can include equipment for cryogenic purification of synthesis gas. In an example, the synthesis gas purification system 234 can be configured to remove methane gas or other hydrocarbons from the hydrogen-rich ammonia synthesis gas stream 230. In an example, the synthesis gas purification system 234 can be configured to remove at least a portion of any methane gas or other hydrocarbons that can be present in the hydrogen-rich ammonia synthesis gas stream 230. In an example, the synthesis gas purification system 234 can be configured to remove all of the methane gas or other hydrocarbons or carbon species that can be present in the hydrogen-rich ammonia synthesis gas stream 230. In an example, an effluent of the synthesis gas purification system 234 can include a purified ammonia synthesis gas stream 236.

[0103] In an example, the synthesis gas purification system 234 can include a reject stream 256 that includes methane gas or other hydrocarbons or carbon species removed from the hydrogen-rich ammonia synthesis gas stream 230. In an example, the reject stream 256 or a portion thereof can be directed to the SMR primary reformer 210 to be used as fuel. In an example, if the reject stream 256 is used as fuel for the SMR primary reformer 210, it can supplement and / or replace the fuel stream 214 and / or the methane-rich gas (or a portion thereof) from the integrated steam cracking unit. In an example, if desired, the reject stream 256 or a portion thereof can be directed to the cracking furnace of the integrated steam cracking unit to be used as fuel.

[0104] In an example, the purified ammonia synthesis gas stream 236 can include no more than a negligible amount of hydrocarbons. In an example, at least 99 mol% of the purified ammonia synthesis gas stream 236 consists of a mixture of hydrogen and nitrogen. In an example, the purified ammonia synthesis gas stream 236 can include at least 74 mol% hydrogen. In an example, the purified ammonia synthesis gas stream 236 can include at least 24 mol% nitrogen. In an example, the purified ammonia synthesis gas stream 236 can include 75 mol% hydrogen and 25 mol% nitrogen.

[0105] In an example, a portion 238a of the purified ammonia synthesis gas stream 236 can be directed to the steam cracking unit to supplement the hydrogen-rich stream recovered by the recovery system of the steam cracking unit for use as fuel for the cracking furnace. In an example, the remaining portion of the purified ammonia synthesis gas stream 236 can be directed to the ammonia synthesis system 240. In an example, the portion 238a of the purified ammonia synthesis gas stream 236 is not directed to the steam cracking unit, and all of the purified ammonia synthesis gas stream 236 is sent to the ammonia synthesis system 240.

[0106] In an example, a portion 238a of the purified ammonia synthesis gas stream 236 can be directed to the steam cracking unit to supplement the hydrogen-rich stream recovered by the recovery system of the steam cracking unit for use as fuel for the cracking furnace. In an example, the remaining portion of the purified ammonia synthesis gas stream 236 can be directed to the ammonia synthesis system 240. In an example, the portion 238a of the purified ammonia synthesis gas stream 236 is not directed to the steam cracking unit, and all of the purified ammonia synthesis gas stream 236 is sent to the ammonia synthesis system 240.

[0107] In an example, the integrated system and method described herein can be configured to affect the hydrogen concentration of the fuel feed to the cracking furnace by controlling and / or adjusting the supplementation of the hydrogen-rich stream recovered by the recovery system of the steam cracking unit with the portion 232a of the hydrogen-rich ammonia synthesis gas stream 230 and / or the portion 238a of the purified ammonia synthesis gas stream 236.

[0108] In an example, a portion 238b of the purified ammonia synthesis gas stream 236 can be used as fuel for the SMR process. In an example, the portion 238b of the purified ammonia synthesis gas stream 236 can be combined with and / or used in place of the fuel 214. In an example, the portion 238b of the purified ammonia synthesis gas stream 236 can be combined with at least a portion of the methane-rich gas from the integrated steam cracking unit to be used as fuel to supplement and / or replace the fuel 214. In an example, the portion 238b of the purified ammonia synthesis gas stream 236 can be used to supplement and / or replace the fuel 214 in place of and / or in combination with the portion 232b of the hydrogen-rich ammonia synthesis gas stream 230. In an example, the portion 238b of the purified ammonia synthesis gas stream 236 can have a lower or even no hydrocarbon or methane content, thereby reducing and / or eliminating carbon emissions when used as fuel for the SMR process.

[0109] In an example, the blue ammonia unit 130 can include the ammonia synthesis system 136 implemented as the ammonia synthesis system 240.

[0110] In an example, at least some of the purified ammonia synthesis gas stream 236 is not redirected to the integrated steam cracking unit or SMR process. In an example, at least some of the purified ammonia synthesis gas stream 236 that is not redirected elsewhere can be fed to an ammonia synthesis system 240 that can be used to form ammonia. In an example, an effluent of the ammonia synthesis system 240 can include an ammonia stream 242.

[0111] Type 2.

[0112] In an example, the blue ammonia unit 130 that is illustrated for integration with a steam cracking unit can include an autothermal reformer (ATR) as at least a portion of the hydrogen generation system 132.

[0113] In an example, a blue ammonia unit can be implemented as illustrated in Figure 2B The same item numbers indicate components that are the same or similar. In cases where there is a difference in the same item, the item is noted with a (‘). Figure 2A Figure 2A Figure 2B

[0114] In an example, the blue ammonia unit 200’ can include a steam pre-reformer 244 and an autothermal reformer (ATR) 246 in place of the SMR process described with reference to FIG. 2. In an example, the blue ammonia unit 200’ can include an air separation unit (ASU) 248.

[0115] In an example, a natural gas feed 206, which can include at least in part a methane- rich gas stream from a steam cracking unit, can be fed to the steam pre-reformer 244. In an example, the methane-rich gas stream from the steam cracking unit can make up all of the natural gas feed 206. In an example, the methane-rich gas stream from the steam cracking unit can supplement the natural gas feed 206. In an example, at least a portion of the natural gas feed 206 can be sourced from a source other than the integrated steam cracking unit.

[0116] In an example, a steam stream 208 can be fed to the steam pre-reformer 244. In an example, in the steam pre-reformer 244, methane and other heavier hydrocarbons, if present, can be steam reformed. In an example, products of the heavier hydrocarbon reforming can also be methanated.

[0117] In an example, the steam pre-reformer 244 can use a catalyst. In an example, the catalyst can include nickel. In an example, the reactions in the steam pre-reformer 244 can require heat. In an example, the heat for the steam pre-reformer 244 can be provided by one or more electric heaters and / or by combusting a fuel. In an example, a fuel 214 can be used as similarly discussed with reference to Figure 2A In an example, the same as previously with reference to Figure 2A ​​​As discussed, fuel 214 can be supplemented and / or replaced by at least a portion of the methane-rich gas stream from the integrated steam cracking unit.

[0118] In an example, one or more of the following three reactions can occur in the steam pre-reformer 244:

[0119] The steam reforming reaction of equation (3):

[0120] CH4 + H2O → CO + 3H2(3)

[0121] The water gas shift reaction of equation (4):

[0122] CO + H2O → H2 + CO2(4)

[0123] The methanation reaction of equation (5):

[0124] CO + 3H2 → CH4 + H2O(5)

[0125] In an example, the effluent of the steam pre-reformer 244 can be fed to the ATR 246. In an example, the ASU 248 can be configured to include an air feed 250 and output an oxygen stream 252 and a nitrogen stream 254. Other air separation systems can also be employed. In an example, either or both of the oxygen stream 252 and the nitrogen stream 254 can include negligible amounts of other gases. In an example, either or both of the oxygen stream 252 and / or the nitrogen stream 254 can be pure gases with respective oxygen and nitrogen concentrations of 99 mol% or greater, respectively.

[0126] In an example, the oxygen stream 252 from the ASU 248 can be fed to the ATR 246. In an example, in the ATR 246, oxygen and carbon dioxide or steam can react with methane, resulting in hydrogen. In an example, the reaction in the ATR 246 can occur without external heat input. The reaction can occur in a single chamber, in which methane is partially oxidized. In an example, the reactions that can occur in the ATR 246 can include either or both of equations (6) and (7):

[0127] 2CH4 + O2 + CO2 → 3H2 + 3CO + H2O(6)

[0128] 4CH4 + O2 + 2H2O → 10H2 + 4CO(7)

[0129] Accordingly, the effluent from the ATR 246 can include a syngas mixture 220’. In an example, the syngas mixture 220’ can be fed to a water gas shift reactor (WGS) 222, and then the effluent from the WGS 222 can be fed to a CO2 separator 228, as earlier described with reference to Figure 2A

[0130] In an example, the effluent from the CO2 separator 228 can include a hydrogen-rich ammonia synthesis gas stream 230’. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can include hydrogen and methane. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can include 96 mol% or more of hydrogen. In an example, the remainder of the hydrogen-rich ammonia synthesis gas stream 230’ can include primarily methane gas. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can include 4 mol% or less of methane. In an example, there can be negligible amounts of other substances in the hydrogen-rich ammonia synthesis gas stream 230’ other than hydrogen and methane. Figure 2B In an example, in a system where nitrogen is not introduced or is not introduced in large amounts in the process prior to the CO2 separator 228, the hydrogen-rich ammonia synthesis gas stream 230’ can be substantially free of nitrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can contain only negligible amounts of nitrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can be free of nitrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can contain primarily hydrogen. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can contain hydrogen in a concentration of 96 mol% or more. In an example, the remainder of the hydrogen-rich ammonia synthesis gas stream 230’ can include primarily methane gas. In an example, the hydrogen-rich ammonia synthesis gas stream 230’ can include 4 mol% or less of methane. In an example, there can be negligible amounts of other substances in the hydrogen-rich ammonia synthesis gas stream 230’ other than hydrogen and methane.

[0131] In an example, as described with reference to Figure 2A Similarly described, at least a portion 232a’ of the hydrogen-rich ammonia synthesis gas stream 230’ can be directed to the steam cracking unit to supplement the hydrogen-rich stream recovered by the recovery system of the steam cracking unit to be used as fuel for the cracking furnace. In an example, the remainder of the hydrogen-rich ammonia synthesis gas stream 230’ can be directed to a syngas purification system 234’. In an example, the portion 232a’ of the hydrogen-rich ammonia synthesis gas stream 230’ is not directed to the steam cracking unit, and all of the hydrogen-rich ammonia synthesis gas stream 230’ is sent to the syngas purification system 234’.

[0132] In an example, another portion 232b’ of the hydrogen-rich ammonia synthesis gas stream 230’ can be used as fuel for the SMR process. In an example, the portion 232b’ of the hydrogen-rich ammonia synthesis gas stream 230’ can be combined with and / or used in place of the fuel 214. In an example, the portion 232b’ of the hydrogen-rich ammonia synthesis gas stream 230’ can be combined with at least a portion of the methane-rich gas from the integrated steam cracking unit to be used as fuel to supplement and / or replace the fuel 214.

[0133] In an example, the blue ammonia unit 130 can include an ammonia synthesis gas purification system 134 implemented as the syngas purification system 234’.

[0134] ​In an example, at least a portion of the hydrogen-rich gas stream from the steam cracking unit can be combined with the hydrogen-rich ammonia synthesis gas stream 230' prior to directing the hydrogen-rich ammonia synthesis gas stream 230' to the synthesis gas purification system 234'. In an example, by combining at least a portion of the hydrogen-rich gas stream from the steam cracking unit with the hydrogen-rich ammonia synthesis gas stream 230', the synthesis gas purification system 234' of the blue ammonia unit 200' can be utilized to further purify at least that portion of the hydrogen-rich gas stream from the steam cracking unit. In an example, the hydrogen-rich gas stream from the steam cracking unit to be used as fuel in the cracking furnace of the steam cracking unit can be combined with the hydrogen-rich ammonia synthesis gas stream 230' prior to the synthesis gas purification system 234'.

[0135] In an example, the synthesis gas purification system 234' can include any suitable purification equipment. In an example, the synthesis gas purification system 234' can include an absorption column, a scrubbing column, or a combination thereof. In an example, the synthesis gas purification system 234' can be configured to remove at least a portion of any methane gas or other hydrocarbons or carbon species that can be present in the hydrogen-rich ammonia synthesis gas stream 230'. In an example, liquid nitrogen can be used in the synthesis gas purification system 234' as a purge stream to separate out carbon species. In an example, the synthesis gas purification system 234' can include a nitrogen feed 254. In an example, a nitrogen stream 254 from the ASU 248 can be fed to the synthesis gas purification system 234' and / or mixed with the product gas of the synthesis gas purification system 234'. In an example, the nitrogen feed 254 can be fed to the synthesis gas purification system 234' as a gas, a liquid, or both. In an example, a portion of the nitrogen feed 254 can be expanded and thus liquefied to provide a liquid nitrogen purge stream for use in the synthesis gas purification system 234'. In an example, a portion of the nitrogen feed 254 can be introduced as a gas to provide a nitrogen source for ammonia synthesis.

[0136] In an example, the synthesis gas purification system 234' can include a reject stream 256' that includes methane gas or other hydrocarbons or carbon species removed from the hydrogen-rich ammonia synthesis gas stream 230'. In an example, the reject stream 256' or a portion thereof can be directed to the steam pre-reformer 244 for use as fuel. In an example, if the reject stream 256' is used as fuel for the steam pre-reformer 244, it can supplement and / or replace the fuel stream 214 and / or the methane-rich gas from the integrated steam cracking unit (or a portion thereof). In an example, the reject stream 256' or a portion thereof can be directed to the cracking furnace of the integrated steam cracking unit for use as fuel, if desired.

[0137] In an example, the effluent of the syngas purification system 234' mixed with nitrogen gas from the nitrogen stream 254 can include a purified ammonia synthesis gas stream 236'. In an example, the purified ammonia synthesis gas stream 236' can include no more than a negligible amount of hydrocarbons. In an example, at least 99 mol% of the purified ammonia synthesis gas stream 236' consists of a mixture of hydrogen and nitrogen. In an example, the purified ammonia synthesis gas stream 236' can include at least 74 mol% hydrogen. In an example, the purified ammonia synthesis gas stream 236' can include at least 24 mol% nitrogen. In an example, the purified ammonia synthesis gas stream 236' can include 75 mol% hydrogen and 25 mol% nitrogen.

[0138] In an example, as earlier referenced with respect to Figure 2A Similarly described, a portion 238a' of the purified ammonia synthesis gas stream 236' can be directed to the steam cracking unit to supplement the hydrogen-rich stream recovered by the recovery system of the steam cracking unit for use as fuel in the cracking furnace. In an example, where all of the hydrogen-rich stream from the steam cracking unit intended for use as fuel in the cracking furnace of the steam cracking plant is combined with the hydrogen-rich ammonia synthesis gas stream 230' prior to the syngas purification system 234', the portion 238a' of the purified ammonia synthesis gas stream 236' directed to the steam cracking unit can constitute the only hydrogen-containing fuel stream supplied to the cracking furnace of the steam cracking unit. In an example, the remaining portion of the purified ammonia synthesis gas stream 236' can be directed to the ammonia synthesis system 240. In an example, the portion 238a' of the purified ammonia synthesis gas stream 236' is not directed to the steam cracking unit and all of the purified ammonia synthesis gas stream 236' is sent to the ammonia synthesis system 240.

[0139] In an example, the portion 238a' of the purified ammonia synthesis gas stream 236' can be directed to the steam cracking unit only when the portion 232a' of the hydrogen-rich ammonia synthesis gas stream 230' is not directed to the steam cracking unit. In an example, the portion 232a' of the hydrogen-rich ammonia synthesis gas stream 230' can be directed to the steam cracking unit only when the portion 238a' of the purified ammonia synthesis gas stream 236' is not directed to the steam cracking unit. In an example, both the portion 232a' of the hydrogen-rich ammonia synthesis gas stream 230' and the portion 238a' of the purified ammonia synthesis gas stream 236' can be directed to the steam cracking plant to supplement the hydrogen-rich stream recovered by the recovery system of the steam cracking unit for use as fuel in the cracking furnace.

[0140] In the example, a portion 238b' of the purified ammonia synthesis gas stream 236' can be used as fuel for the pre-reformer 244. In the example, a portion 238b' of the purified ammonia synthesis gas stream 236' can be combined with and / or used in place of fuel 214. In the example, a portion 238b' of the purified ammonia synthesis gas stream 236' can be combined with at least a portion of methane-rich gas from the integrated steam cracking unit to serve as supplemental and / or alternative fuel to fuel 214. In the example, a portion 238b' of the purified ammonia synthesis gas stream 236' can be used to replace a portion 232b' of the hydrogen-rich ammonia synthesis gas stream 230' and / or used together with that portion to supplement and / or replace fuel 214. In the example, a portion 238b' of the purified ammonia synthesis gas stream 236' may have low or even no hydrocarbon or methane content, thereby reducing and / or eliminating carbon emissions when used as fuel for the pre-reformer 244.

[0141] In the example, the integrated system and method described herein can be configured to influence the hydrogen concentration of the fuel feed to the cracking furnace by controlling and / or adjusting the supplementation of the hydrogen-rich stream recovered by the recovery system of the steam cracking unit with a portion 232a' of the hydrogen-rich ammonia synthesis gas stream 230' and / or a portion 238a' of the purified ammonia synthesis gas stream 236', or by replacing the hydrogen-rich stream recovered by the recovery system of the steam cracking unit with a portion 238a' of the purified ammonia synthesis gas stream 236', as described above.

[0142] In the example, as referenced Figure 2A Similarly, at least a portion of the purified ammonia synthesis gas stream 236' is fed into the ammonia synthesis system 240 for reaction to form ammonia. In this example, the effluent from the ammonia synthesis system 240 may include ammonia stream 242.

[0143] Type 3:

[0144] In the example, the blue ammonia unit can be as follows: Figure 2C The example implementation. The same item number indicates the same as the previous one. Figure 2B Same or similar components. Figure 2C and Figure 2B If there are differences among identical items, the item is marked with ('').

[0145] In the example, Figure 2C The blue ammonia unit 200'' can be configured and include a reference Figure 2B The components are identical to those described for the blue ammonia unit 200', except for the input positions of the nitrogen stream 254 and the syngas purification system 234''. Figure 2C As shown, the nitrogen stream 254'' air separation unit (ASU) 248 can be directed to the ammonia synthesis system 240 to combine with hydrogen and produce an ammonia stream 242.

[0146] In an example, the syngas purification system 234’’ can include a purifier. In an example, the purifier can include a pressure swing adsorption (PSA) process. In an example, the PSA process refers to a technique that utilizes an adsorbent material to separate gaseous substances from a gas mixture under pressure. The PSA process can operate at near ambient temperatures. Any suitable adsorbent material can be used. In an example, the PSA of the syngas purification system 234’’ can include a zeolite (e.g., 5A zeolite), activated carbon, or other material suitable for adsorbing methane or other hydrocarbons and / or other carbon species (such as CO and CO2) that can be present in the hydrogen-rich ammonia synthesis gas stream 230’. In an example, the syngas purification system 234’’ can be configured to remove at least a portion of any methane gas or other hydrocarbons or carbon species that can be present in the hydrogen-rich ammonia synthesis gas stream 230’. In an example, the syngas purification system 234’’ can be configured to remove all of the methane gas or other hydrocarbons or carbon species that can be present in the hydrogen-rich ammonia synthesis gas stream 230’.

[0147] In an example, the syngas purification system 234’’ can include a waste stream 256’’ that includes the methane gas or other hydrocarbons or carbon species removed from the hydrogen-rich ammonia synthesis gas stream 230’. In an example, the waste stream 256’’ or a portion thereof can be directed to the steam pre-reformer 244 for use as a fuel. In an example, if the waste stream 256’’ is used as a fuel for the steam pre-reformer 244, it can supplement and / or replace the fuel stream 214 and / or the methane-rich gas (or a portion thereof) from the integrated steam cracking unit. In an example, if desired, the waste stream 256’’ or a portion thereof can be directed to the cracking furnace of the integrated steam cracking unit for use as a fuel.

[0148] In an example, by inputting a nitrogen stream from the ASU 248 into the ammonia synthesis system 240, rather than at or just after the syngas purification system 234’’, the blue ammonia unit 200’’ can produce a purified ammonia synthesis gas stream 236’’ that is free of nitrogen gas. In an example, the purified ammonia synthesis gas stream 236’’ can include a hydrogen stream that is primarily hydrogen. In an example, the purified ammonia synthesis gas stream 236’’ can include a hydrogen concentration of >99.5 mol%. In an example, the purified ammonia synthesis gas stream 236’’ can include a 100 mol% pure hydrogen stream.

[0149] In an example, one or more of the same fluid connections between the steam cracking unit and the blue ammonia unit can be implemented with the blue ammonia unit 200’’ as those described previously with reference to the blue ammonia unit 200’. In an example, at least a portion of the methane-rich gas stream from the integrated steam cracking unit can be directed to the steam pre-reformer 244 for use as a fuel and / or feed.

[0150] In the example, the hydrogen-rich stream from the integrated steam cracking unit can supplement at least a portion of the hydrogen-rich ammonia syngas stream 230'. In the example, the hydrogen-rich stream from the integrated steam cracking unit can supplement at least a portion of the purified ammonia syngas stream 236''. In the example, at least a portion of the hydrogen-rich stream from the integrated steam cracking unit can be combined with the hydrogen-rich ammonia syngas stream 230' before the syngas purification system 234''. In the example, all the hydrogen-rich streams from the integrated steam cracking unit can be combined with the hydrogen-rich ammonia syngas stream 230' before the syngas purification system 234''. In the example, a portion of the purified ammonia syngas stream 236'' can be the only hydrogen-containing stream directed to the cracking furnace of the integrated steam cracking unit for use as fuel. In the example, a portion of the purified ammonia syngas stream 236'' can replace the hydrogen-rich stream from the steam cracking unit as a fuel supply source to the cracking furnace of the integrated steam cracking unit.

[0151] In the example, a portion 238b'' of the purified ammonia synthesis gas stream 236'' can be used as fuel for the pre-reformer 244. In the example, a portion 238b'' of the purified ammonia synthesis gas stream 236'' can be combined with and / or used in place of fuel 214. In the example, a portion 238b'' of the purified ammonia synthesis gas stream 236'' can be combined with at least a portion of methane-rich gas from the integrated steam cracking unit to serve as supplemental and / or alternative fuel to fuel 214. In the example, a portion 238b'' of the purified ammonia synthesis gas stream 236'' can be used to replace a portion 232b'' of the hydrogen-rich ammonia synthesis gas stream 230'' and / or used together with that portion to supplement and / or replace fuel 214. In the example, a portion 238b'' of the purified ammonia synthesis gas stream 236'' may have low or no hydrocarbon or methane content, thereby reducing and / or eliminating carbon emissions when used as fuel for the pre-reformer 244.

[0152] In the example, the integrated systems and methods described herein can be configured to influence the hydrogen concentration of the fuel feed to the cracking furnace by controlling and / or adjusting the supplementation of a hydrogen-rich stream of hydrogen-containing gas directed to the cracking furnace as fuel, as previously referenced. Figure 2B As described.

[0153] Steam cracking techniques

[0154] In the examples, the methods and systems described include fluidly connecting a steam cracking unit to a blue ammonia unit, as previously described. Different types of steam cracking units can be implemented in the integrated methods and systems.

[0155] In the example, the steam cracking unit 110 may include a cracking furnace 112 as having, for example... Figure 3AA gas feed cracking furnace 300 is shown. In an example, the cracking furnace 300 can include a radiant section 302 and a convection section 304. A combustion air source 306 can be used with a fuel gas 308 as a combustion mixture for the radiant section 302 of the furnace. In an example, the combustion air can be preheated. In an example, the preheating of the combustion air can be accomplished using a heater 310 that recovers heat from flue gas in the convection section 304 of the cracking furnace 300. In an example, a hydrocarbon gas feed 312 can be fed to one or more reaction tubes 314 disposed in the radiant section 302 of the cracking furnace 300. In an example, the feed 312 can be preheated prior to being fed to the one or more reaction tubes 314. In an example, the feed 312 can be preheated via a heater 316 that recovers heat from the convection section of the furnace, via a feed / effluent heat exchanger 318 that transfers heat from effluent cracked gas to the feed 312, or a combination thereof. In an example, a cracking reaction can occur in the one or more reaction tubes 314. In an example, the cracking reaction can produce an effluent cracked gas. In an example, the effluent cracked gas can contain methane, hydrogen, and one or more olefins. In an example, the effluent cracked gas can be cooled by one or more quenchers 320. In an example, the fuel gas 308 can include a hydrogen-rich stream or a high-purity hydrogen stream.

[0156] In an example, as Figure 3B illustrated, the steam cracking unit 110 can include a cracking furnace 112 as a liquid feed cracking furnace 350. As Figure 3B illustrated, the cracking furnace 350 of the steam cracking unit can include a liquid naphtha feed (LN feed) 352. In an example, as shown, the liquid feed 352 can be preheated prior to entering one or more reaction tubes 354 in a radiant section 356 of the cracking furnace 350. In an example, the feed can be preheated using one or more heaters 358 to vaporize prior to injection into the one or more reaction tubes 354. In an example, the one or more heaters 358 can be configured to recover flue gas heat from a convection section 366 of the cracking furnace. In an example, a fuel gas 360 and combustion air 362 can be fed to the radiant section 356 of the cracking furnace 350 for combustion and heat generation. One or more quenchers 364 can be used to quench effluent cracked gas of the cracking furnace 350.

[0157] In an example, the steam cracking unit 110 can include a recovery system 114 in which the effluent cracked gas can be processed to further separate methane, olefins, and hydrogen. In an example, the process can produce a hydrogen-rich stream, an olefin stream, and a methane-rich gas stream.

[0158] In an example, the cracking furnace design can include one or more burners capable of burning 100% pure hydrogen.

[0159] In an example, a cracker furnace can use high purity hydrogen as a fuel gas to achieve net zero CO2emissions from the furnace. In an example, the high purity hydrogen gas can be the only fuel gas other than combustion air. In an example, the combustion air is free or substantially free (i.e., no more than an insignificant amount or 1 mol% or less) of hydrocarbons.

[0160] In an example, a cracker furnace design can use one or more features to provide the most energy efficient capital and energy solution to achieve the lowest overall carbon emissions.

[0161] In an example, the combustion air can be preheated to minimize the required furnace firing load and associated inlet hydrogen. In an example, the feed to the cracker furnace can be preheated. In an example, both the combustion air and the feed to the cracker furnace can be preheated. In an example, the combustion air can be preheated by recovering heat from the convection section of the cracker furnace by a heat exchanger, one or more electric heaters, or any combination thereof. In an example, the hydrocarbon feed to the cracker furnace can be preheated via one or more heat exchangers, with cracker furnace effluent gas, by recovering heat from the convection section of the cracker furnace, by one or more electric heaters, or any combination thereof. In an example, the liquid naphtha feed can be heated to produce a gaseous feed before it enters one or more reactor tubes of the cracker furnace.

[0162] In an example, the combustion air can be preheated to a temperature of about 400°C to about 450°C or about 650°C to about 750°C. In an example, the hydrocarbon feed to the cracker furnace can be preheated to about 620°C to about 640°C before it is introduced into one or more reactor tubes of the cracker furnace.

[0163] In examples, cracker furnace 112 can be configured to apply a combustion air preheat design as disclosed in, for example, co-pending U.S. Application No. 17 / 880,973, filed August 4, 2022, entitled “Low CO2 emission Ethane Cracker,” which is incorporated by reference herein in its entirety. In examples, the cracker furnace can be configured to preheat combustion air as described in, for example, co-pending U.S. Application No. 63 / 516,104, filed July 27, 2023, entitled “Net Zero Ethane Cracker with no External Hydrogen Import,” which is incorporated by reference herein in its entirety. In examples, the cracker furnace can be configured to preheat the hydrocarbon feed and / or combustion air as described in, for example, co-pending U.S. Application No. 63 / 516,066, filed July 27, 2023, entitled “100% Hydrogen-Fired Liquid Cracking Furnace,” which is incorporated by reference herein in its entirety.

[0164] As Figure 4 illustrated, and for example, as discussed in co-pending U.S. Application No. 17 / 880,973, the steam cracking unit can include a recovery system 114 as recovery system 400 to recover a methane-rich gas stream, a hydrogen-rich gas stream, and an olefin stream.

[0165] Figure 4 An example of recovery system 400 is illustrated. Other recovery system designs can also be employed.

[0166] In examples, system 400 can be implemented for an ethane cracking process. The cracked gas process stream from the cracker furnace can include hydrogen, methane, and ethylene. In examples, the cracked gas process stream can enter the illustrated process, for example, at a temperature of about -73°C. The temperatures and pressures in the present description of recovery system 400 are merely illustrative of particular embodiments of the process. In examples, the temperatures / pressures can vary. The cracked gas process stream can be cooled in cold box 408. In examples, cold box 408 can include other cold and hot lines not illustrated here.

[0167] In an example, the light ends of the cracked gas process stream from the cracker 112 can be progressively cooled and passed through knock-out drums 402 and 404 to separate out ethylene. In an example, the light ends of the cracked gas process stream from the cracker 112 can include hydrogen, methane, carbon monoxide, ethylene, ethane, or any combination thereof. The cooling temperature can be configured to manage the approach temperature in the cold box. According to some embodiments, the temperature of the first knock-out drum 402 can be about -115°C ± 10°C, and the temperature of the second knock-out drum can be about -130°C to about -145°C. The ethylene-rich bottoms stream of the knock-out drums 402 and 404 can be combined into an ethylene-rich stream 406. The ethylene-rich stream 406 can be recompressed using a turboexpander / compressor 410 to provide an ethylene recovery fraction 412 that is rich in ethylene.

[0168] In an example, the overhead stream of the methane and hydrogen rich knock-out drums 402 and 404 can be further cooled in the cold box and provided to a third knock-out drum 414. In an example, the temperature of the third knock-out drum 414 can be about -163°C ± 10°C. The overhead stream 416 from the third knock-out drum 414 is rich in hydrogen. The bottoms stream 418 from the third knock-out drum 414 is rich in methane. The temperature of the third knock-out drum 414 can determine the amount of methane separation, i.e., it can determine the purity of the hydrogen stream.

[0169] In an example, the methane-rich bottoms stream 418 can be reheated in the cold box and then exit the system as a methane-rich gas stream 420.

[0170] The hydrogen-rich overhead stream 416 can be reheated in the cold box to provide a reheated hydrogen-rich stream 422. In an example, the temperature of the reheated hydrogen-rich stream 422 can be about -140°C and its pressure can be about 20 barg to about 45 barg.

[0171] In an example, where the hydrogen-rich gas stream that is ultimately output from the recovery system 114 or 400 is to be used as fuel for the cracker of the steam cracking unit from which the hydrocarbons are recovered, the turboexpander / compressor 410 can be used to expand the hydrogen-rich stream 422 to produce an expanded hydrogen-rich stream 424. In an example, the expansion can result in a decrease in the temperature and pressure of the expanded hydrogen-rich stream 424. For example, after expansion, the temperature of the hydrogen-rich stream 424 can be about -177°C and the pressure can be less than about 10 barg, such as about 6 barg. In an example, the expanded hydrogen-rich stream 424 can be reintroduced to the cold box 408, thereby providing a cold stream within the cold box that is capable of providing a sufficient temperature approach to enable the separation of methane and hydrogen in the knock-out drum 414. The expanded hydrogen-rich stream 424 can ultimately exit the cold box as a hydrogen-rich gas stream 426.

[0172] In an example, where the hydrogen-rich gas stream that is ultimately output from the recovery system 114 or 400 is directed to the blue ammonia unit 130 for further purification, the hydrogen-rich overhead stream 416 from the tank 414 can be maintained under pressure. In an example, the hydrogen-rich overhead stream 416 can be simply reheated and sent to the blue ammonia unit 130 to combine with the effluent stream 134 prior to syngas purification system 234, 234’ or 234”. In an example, no expansion of the hydrogen-rich overhead stream 416 will be performed. To provide a gas stream that is cold enough to provide the cooling required in the coldest section of the cold box to achieve the target conditions in the tank 414, in an example, a portion (e.g., about 10-15%) of the hydrogen-rich overhead stream 416 can be separated out and mixed with the methane-rich bottoms stream 418 prior to being reheated in the cold box before being directed to the blue ammonia unit 130. In this way, the vaporization temperature of the methane-rich bottoms stream 418 can be reduced and thus enabled to provide the desired approach temperature.

[0173] In an example, the hydrogen-rich gas stream 426 can include greater than 90 mol% hydrogen or greater than 95 mol% hydrogen, with the balance including mostly methane. In an example, the system 400 can recover more than 90% or more than 95% of the available hydrogen in the pyrolysis gas process stream.

[0174] As described earlier, various integration options can be implemented in the integration of the steam cracking unit 110 and the blue ammonia unit 130.

[0175] Figure 5 Examples of various integration options between the steam cracking unit 110 and the blue ammonia unit 130 are illustrated. In an example, one or more lines, pipes and / or conduits can be used to fluidly connect the steam cracking unit 110 to the blue ammonia unit 130. In an example, one or more valves (not shown) can be included to control the flow through the one or more lines, pipes and / or conduits. In an example, one or more lines, pipes and / or conduits can be used to direct and / or transport one or more streams (feed / effluent) between the steam cracking unit and the blue ammonia unit.

[0176] In an example, as Figure 5 illustrated, the integrated system and method 500 of the steam cracking unit 510 and the blue ammonia unit (not shown) can include one or more of the following features.

[0177] In an example, the integration can include a separation process by a recovery system 512 of the effluent cracked gas 514 from the reaction tubes of the cracking furnace 516. In an example, the cracking furnace 516 can receive a hydrocarbon feed 518. In an example, the cracking furnace 516 can include a steam feed (not shown). In an example, heat can be generated in the cracking furnace 516 by combusting fuel 520 mixed with combustion air 522.

[0178] In an example, the recovery system 512 can be configured to separate a methane- rich gas stream 524 (stream 1) and a hydrogen-containing gas stream, such as a hydrogen-rich gas stream 526 (e.g., 90-95 mol% purity) gas (stream 2). In an example, the recovery system 512 can also include an olefin effluent stream 528 and an optional byproduct effluent stream 542.

[0179] In an example, the hydrogen-rich gas stream 526 can be produced by recovering internally generated hydrogen, i.e., hydrogen generated in the cracking furnace 516 during the pyrolysis process of one or more hydrocarbons contained in the hydrocarbon feed 518. In an example, the recovery can be performed as described, for example, with reference to Figure 4 In an example, the hydrogen concentration of the hydrogen-rich stream 526 can be maximized.

[0180] In an example, the integrated method and system 500 can be configured to send at least a portion of the methane-rich gas stream 524 from the steam cracking unit 510 to the blue ammonia unit. As previously stated, the methane-rich gas stream 524 can be used in the blue ammonia unit as a feed gas and / or as a fuel gas. In an example, the methane-rich gas stream 524 can be used as a feed and / or fuel in the hydrogen generation system of the blue ammonia unit.

[0181] In an example, the integrated method and system 500 can be configured to include directing a hydrogen-containing gas stream from the blue ammonia unit and / or the recovery system 512 to the cracking furnace 516 of the steam cracking unit 510 via conduit or pipeline 544 to be used as at least a portion of the fuel gas in the cracking furnace 516. In an example, the fuel 520 can optionally be supplemented by an external source 546. In an example, the directed hydrogen-containing gas stream can be at least partially sourced from hydrogen gas produced from the methane-rich gas stream 524 directed from the steam cracking unit 510 to the blue ammonia unit. In an example, the hydrogen gas produced from the methane-rich gas stream 524 can be produced in the hydrogen generation system of the blue ammonia unit.

[0182] In an example, the hydrogen-containing gas stream can be drawn from one or more locations of the blue ammonia unit. In an example, the hydrogen-containing gas stream can be drawn from one or more of at least four potential locations.

[0183] In an example, where the blue ammonia unit is Type 1, for example as Figure 2A illustrated, the drawing of the hydrogen-containing gas stream can be a portion of the hydrogen-rich ammonia synthesis gas stream 530 (stream 4) drawn between the CO2 separator and the syngas purification system. At this location, the hydrogen purity can be approximately 65 mol% and the stream contains approximately 2 mol% of residual methane and CO. Using this stream as fuel gas can result in significant but incomplete decarbonization of the steam cracking plant.

[0184] In an example, the hydrogen-containing stream can be a portion of purified ammonia synthesis gas stream 532 (stream 5) drawn downstream of the syngas purification system in a Type 1 Blue Ammonia Unit, where the hydrogen-containing stream can be free of methane, hydrocarbons, and other carbon species, and can contain approximately 75 mol% hydrogen and 25 mol% nitrogen. In an example, use of this stream can provide an opportunity for high or complete decarbonization of the steam cracking plant unit.

[0185] In an example, where the Blue Ammonia Unit is Type 2, for example as illustrated in Figure 2B In an example, the hydrogen-containing stream can be a portion of purified ammonia synthesis gas stream 532 (stream 5) drawn downstream of the syngas purification system in a Type 1 Blue Ammonia Unit, where the hydrogen-containing stream can be free of methane, hydrocarbons, and other carbon species, and can contain approximately 75 mol% hydrogen and 25 mol% nitrogen. In an example, use of this stream can provide an opportunity for high or complete decarbonization of the steam cracking plant unit.

[0186] In an example, the hydrogen-containing stream can be a portion of purified ammonia synthesis gas stream 532 (stream 5) drawn downstream of the syngas purification system in a Type 1 Blue Ammonia Unit, where the hydrogen-containing stream can be free of methane, hydrocarbons, and other carbon species, and can contain approximately 75 mol% hydrogen and 25 mol% nitrogen. In an example, use of this stream can provide an opportunity for high or complete decarbonization of the steam cracking plant unit.

[0187] In an example, where the Blue Ammonia Unit is Type 3, for example as illustrated in Figure 2C In an example, the hydrogen-containing stream can be a portion of purified ammonia synthesis gas stream 532 (stream 5) drawn downstream of the syngas purification system in a Type 1 Blue Ammonia Unit, where the hydrogen-containing stream can be free of methane, hydrocarbons, and other carbon species, and can contain approximately 75 mol% hydrogen and 25 mol% nitrogen. In an example, use of this stream can provide an opportunity for high or complete decarbonization of the steam cracking plant unit.

[0188] In an example, the hydrogen-containing stream can be a portion of purified ammonia synthesis gas stream 536 (stream 7) drawn downstream of the syngas purification system (e.g., PSA) in a Type 3 Blue Ammonia Unit, where the hydrogen-containing stream can have a very high purity, i.e., > 99.5 mol%, or be pure hydrogen, i.e., 100 mol%. Use of this stream can provide complete decarbonization of the cracking plant.

[0189] In an example, disposition of internal hydrogen produced in the steam cracking unit can depend on the ammonia unit configuration.

[0190] In an example, by integration as described herein, the cracking furnace 516 can be partially or completely decarbonized, resulting in a flue gas stream 548 having a reduced amount of, or no, CO2.

[0191] In an example, for partial decarbonization, some or all of the internally generated hydrogen containing stream (stream 2), such as hydrogen rich stream 526 from the steam cracking unit, can be used as fuel gas for the cracking furnace, supplemented by one or more hydrogen containing streams 530, 532, 534, and 536 (streams 4, 5, 6, or 7) from the ammonia unit.

[0192] In an example, to enhance decarbonization or to achieve full decarbonization when employing a Type 1 or Type 2 blue ammonia unit as previously described, the method can include purifying the hydrogen rich stream 526 from the steam cracking unit in a supplemental PSA unit 538. In an example, the hydrogen rich stream 526 can be directed to the PSA unit 538 to produce a high purity hydrogen stream 540 (stream 3). In an example, the high purity hydrogen stream 540 can be combined with a carbon free hydrogen containing stream, such as hydrogen containing stream 532 or 536 (streams 5 or 7) from the blue ammonia unit, as fuel gas to the furnace.

[0193] In an example, to enhance decarbonization or to achieve full decarbonization when integrating a Type 3 blue ammonia unit as previously described, the method can include outputting the hydrogen containing stream 526 from the steam cracking unit to the blue ammonia unit (counter current 6) entering immediately upstream of the ammonia purification system (e.g., PSA unit) of the blue ammonia unit to avoid duplication of equipment and returning the purified hydrogen containing stream from the ammonia unit PSA as part of the purified ammonia synthesis gas stream 536 (stream 7).

[0194] In an example, the furnace design of the cracking system can include the following elements to provide the most energy efficient solution to achieve the lowest overall carbon emissions: a) configured to apply a combustion air preheat design, preferably heating the air to 425-450°C, to minimize the furnace combustion load and the associated required import hydrogen rich stream; b) include in the furnace a burner capable of burning 100% pure hydrogen; and c) configured to use (optionally only use) internally generated hydrogen rich or high purity hydrogen gas plus imported hydrogen rich gas as fuel in the cracking furnace.

[0195] In an example, the method and system can include one or more of the following elements: a) selectively use electric drive of the main compressor in the recovery section as needed to achieve a neutral or net export steam balance for the combined cracking plant and blue ammonia unit. This requirement can vary based on the source of the imported hydrogen rich gas; and b) use green imported power, with no CO2 emissions.

[0196] In an example, one or more advantages can be obtained from the systems and methods disclosed above. Reducing carbon emissions has become a key factor in assessing the viability of a project or technology. In an example, the described methods and systems can provide an effective way to achieve low carbon or net zero carbon emissions, with significant potential for environmental and economic benefits.

[0197] In an example, integrating a steam cracking plant with a blue ammonia unit as described can minimize combined unit capital costs by sharing equipment and providing a reduced capital option compared to applying carbon capture directly on an olefins plant.

[0198] In an example, integrating a steam cracking plant with a blue ammonia unit as described can minimize combined unit capital costs by maximizing utilization of internally generated hydrogen and maximum air preheat on furnaces, which can minimize the net hydrogen required for the blue ammonia unit.

[0199] In an example, integrating a steam cracking plant with a blue ammonia unit as described can minimize the net hydrogen required and, therefore, the associated CO2 produced in the blue ammonia unit that needs to be captured and / or stored.

[0200] In an example, integrating a steam cracking plant with a blue ammonia unit as described can enable efficient integration of feed and product streams, which can reduce combined unit energy consumption.

[0201] In an example, the integration can therefore reduce the need for ammonia unit feed desulfurization, as the methane-rich gas from the cracking plant production can be sulfur-free.

[0202] In an example, the systems described herein can include one or more control systems, sensors, and other standard components that enable control and operation of the systems.

[0203] In an example, although not shown, the systems described herein can include one or more sensors as commonly used in the art. In an example, the sensors can be used to monitor the operation of the described systems. Non-limiting examples of one or more sensors can include temperature sensors, pressure sensors, flow meters, and other similar sensors.

[0204] In an example (but not shown), one or more control systems can include one or more controllers, and / or other suitable computing devices can be used to control one or more portions of the systems described herein. The controllers can include one or more processors and memory communicatively coupled to each other. In the illustrated example, the memory can be used to store logic instructions to operate and / or control and / or monitor the operation of one or more described components. In an example, the controllers can include or be coupled to input / output devices, such as monitors, keyboards, speakers, microphones, computer mice, etc. In an example, the one or more controllers can also include one or more communication components, such as transceivers or similar structures, to enable wired and / or wireless communication. In an example, this can enable remote operation of one or more systems described herein.

[0205] In an example, the memory associated with the one or more controllers and / or other suitable computing devices can be a non-transitory computer-readable medium. The memory can store an operating system and one or more software applications, instructions, programs, and / or data to implement the methods described herein and the functionality attributed to the various systems. In various implementations, the memory can be implemented using any suitable memory technology, such as static random access memory (SRAM), synchronous dynamic RAM (SDRAM), nonvolatile / Flash-type memory, or any other type of memory capable of storing information. The control system can include any number of logical components, program components, and physical components.

[0206] The logic instructions can include one or more software modules and / or other information sufficient to implement autonomous operations, safety procedures, and routine maintenance processes. Any operations described for the systems can be implemented in hardware, software, or a combination thereof. In the context of software, the operations represent computer-executable instructions stored on one or more computer-readable storage media that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, components, data structures, and the like that perform one or more functions or implement particular abstract data types.

[0207] It will be apparent to those skilled in the art that various modifications and variations can be made to the present application without departing from the spirit or scope of the application. Thus, it is intended that the present application cover the modifications and variations of this application provided they come within the scope of the appended claims and their equivalents.

Claims

1. A system comprising: A steam pyrolysis unit, the steam pyrolysis unit including a pyrolysis furnace; A blue ammonia unit, which is in fluid communication with the steam cracking unit, is configured to generate a hydrogen-containing gas stream; A first conduit is configured to direct the hydrogen-containing gas stream to the steam cracking unit for use as fuel.

2. The system according to claim 1, wherein the blue ammonia unit further comprises a hydrogen generation system configured to generate a hydrogen-rich ammonia synthesis gas stream, wherein the hydrogen-containing gas stream includes the hydrogen-rich ammonia synthesis gas stream.

3. The system according to claim 1, wherein the blue ammonia unit further comprises an ammonia synthesis gas purification system configured to generate a purified ammonia synthesis gas stream, wherein the hydrogen-containing gas stream comprises the purified ammonia synthesis gas stream.

4. The system of claim 1, wherein the steam cracking unit further comprises a recovery system configured to receive effluent cracked gas from the cracking furnace and to separate at least a hydrogen-rich gas stream and a methane-rich gas stream from the effluent cracked gas.

5. The system of claim 4, further comprising a second conduit configured to direct the methane-rich gas stream from the steam cracking unit to the blue ammonia unit for use as fuel, feed, or both.

6. The system of claim 5, further comprising a gas compressor configured to pressurize at least a portion of the methane-rich gas stream before it reaches the blue ammonia unit.

7. The system of claim 6, further comprising a gas expander configured to expand the hydrogen-containing gas stream before it reaches the steam cracking unit.

8. The system of claim 7, wherein the gas compressor is powered by energy recovered from the gas expander.

9. The system of claim 7, further comprising a heater configured to heat the hydrogen-containing gas stream before it reaches the gas expander.

10. The system of claim 4, wherein the steam cracking unit further includes a recirculation line configured to direct the hydrogen-rich gas stream from the recovery system to the cracking furnace for use as fuel.

11. The system according to claim 10, wherein: The blue ammonia unit further includes a hydrogen generation system configured to generate a hydrogen-rich ammonia synthesis gas stream, wherein the hydrogen-containing gas stream includes the hydrogen-rich ammonia synthesis gas stream. as well as A fourth conduit is configured to direct at least a portion of the hydrogen-rich ammonia synthesis gas flow to the steam cracking unit for combination with the hydrogen-rich gas flow.

12. The system according to claim 10, wherein: The blue ammonia unit further includes an ammonia synthesis gas purification system configured to generate a purified ammonia synthesis gas stream, wherein the hydrogen-containing gas stream includes the purified ammonia synthesis gas stream. as well as A fourth conduit is configured to direct at least a portion of the purified ammonia synthesis gas stream to the steam cracking unit for combination with the hydrogen-rich gas stream.

13. The system of claim 4, further comprising a third conduit configured to direct at least a portion of the hydrogen-rich gas stream from the steam cracking unit to the blue ammonia unit.

14. The system of claim 13, wherein the blue ammonia unit comprises an ammonia synthesis gas purification system, and wherein all hydrogen-rich gas streams are directed to the ammonia synthesis gas purification system.

15. The system of claim 14, further comprising a fourth conduit configured to direct an effluent from the ammonia syngas purification system via purified ammonia syngas to the pyrolysis furnace of the steam cracking unit for use as fuel.

16. A method comprising: A hydrogen-containing gas stream is generated in the blue ammonia unit; as well as The hydrogen-containing gas stream is directed to the steam cracking unit as fuel.

17. The method of claim 16, further comprising: Methane-rich gas streams are recovered during steam cracking; as well as The methane-rich gas stream is directed to the blue ammonia unit as feed, fuel, or both.

18. The method of claim 16, further comprising recovering a hydrogen-rich gas stream from the effluent of the pyrolysis furnace of the steam pyrolysis unit via pyrolysis gas.

19. The method of claim 18, further comprising directing the recovered hydrogen-rich gas stream to the cracking furnace of the steam cracking unit for use as fuel.

20. The method of claim 19, further comprising supplementing the hydrogen-rich gas stream with a hydrogen-containing gas stream from the blue ammonia unit.

21. The method of claim 20, wherein the hydrogen-containing gas stream comprises at least a portion of the hydrogen-rich ammonia synthesis gas stream generated by the hydrogen generation system of the blue ammonia unit.

22. The method of claim 21, wherein the hydrogen-containing gas stream comprises at least a portion of the purified ammonia syngas stream generated by the ammonia syngas purification system of the blue ammonia unit.

23. The method of claim 18, further comprising directing the hydrogen-rich gas stream to the purification stage of the blue ammonia unit, and directing at least a portion of the purified ammonia syngas stream generated by the ammonia syngas purification system to the pyrolysis furnace of the steam cracking unit for use as fuel.

24. The method of claim 17, further comprising: At least a portion of the methane-rich gas stream, which is directed to the blue ammonia unit, is compressed by a gas compressor before reaching the blue ammonia unit. The hydrogen-containing gas stream generated in the blue ammonia unit is expanded by a gas expander before reaching the steam cracking unit; and The gas compressor is powered by energy recovered from the gas expander.

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