Method and cracking furnace system

Description

/ 22 METHOD AND SYSTEM FOR CRACKING FURNACE FIELD OF REVELATION

[001] The embodiments of the present disclosure relate to steam cracking of liquid hydrocarbons and, specifically, to steam cracking of non-hydroprocessed liquid hydrocarbons. BACKGROUND

[002] Steam cracking is a process in which heat, sometimes supplemented by high pressure and / or catalysts, is used to break down hydrocarbon molecules into lighter molecules. One source of hydrocarbon molecules for steam cracking is liquid hydrocarbons, such as pyrolysis oil, which are derived from plastic waste that has undergone a pyrolysis process. The pyrolysis process is a high-temperature thermochemical degradation reaction that decomposes plastic waste in the absence of oxygen or in a low-oxygen environment to produce pyrolysis oil, gaseous vapor, and tar, with the yields of each depending on the pyrolysis technology. The pyrolysis oil produced, however, often contains impurities such as metals, halogens, chlorine, oxygenates, sulfur, and nitrogen. These impurities have the potential to poison catalysts and damage the steam cracker.As a result, impurities need to be removed from the pyrolysis oil before it can be used in downstream processes (e.g., a steam cracking process).

[003] Impurities in pyrolysis oil can be removed using a variety of techniques. One technique for removing impurities from pyrolysis oil prior to steam cracking is through hydroprocessing. In hydroprocessing, the pyrolysis oil is catalytically processed under a hydrogen atmosphere at elevated temperatures to help eliminate impurities. Hydroprocessing also helps to further saturate the hydrocarbons in the pyrolysis oil, which aids the steam cracking process. Petition 870250087485, dated 09 / 26 / 2025, page 10 / 46 / 22 to produce more ethylene, also reducing fouling precursors. The use of hydroprocessing, however, requires a large capital investment and adds time to the overall processing of pyrolysis oil. As an alternative to such costs, there are other processes that can be used to eliminate impurities from pyrolysis oil. These other processes, however, do not have the capacity to improve the desired saturation of the pyrolysis oil. Therefore, there is a need in the art to help both eliminate impurities in pyrolysis oil and simultaneously improve the saturation of hydrocarbon molecules in pyrolysis oil without the demand for a large capital investment of a hydroprocessing system. SUMMARY

[004] The present disclosure provides a method and a system for steam cracking that help to eliminate impurities in liquid hydrocarbons, such as pyrolysis oil, while improving the saturation of the liquid hydrocarbons without the large capital investment of a hydroprocessing system for the steam cracking system. For this purpose, the present disclosure provides a method for supplying a stream of liquid hydrocarbon to an inlet of a steam cracking furnace and injecting hydrogen gas into the liquid hydrocarbon stream at, or before, the inlet of the steam cracking furnace to produce a mixture of the liquid hydrocarbon and hydrogen gas. The liquid hydrocarbon in the mixture is subjected to steam cracking to produce a reaction product that includes hydrocarbons having shorter carbon chain lengths than before entering the steam cracking furnace.The method of the present disclosure does not involve hydroprocessing of the liquid hydrocarbon prior to steam cracking. For the various embodiments, the reaction product includes at least ethylene.

[005] For the various forms, the hydrocarbon mixture Petition 870250087485, dated 09 / 26 / 2025, page 11 / 46 / 22 liquid and hydrogen gas in the inlet includes 0.1 percent by weight (% by weight) to 10% by weight of hydrogen gas based on the total weight of the mixture. In a further embodiment, the mixture includes 5% by weight to 7% by weight of hydrogen gas based on the total weight of the mixture. In another embodiment, the mixture includes 0.1% by weight to 1% by weight of hydrogen gas based on the total weight of the mixture. In a specific embodiment, the mixture includes 6% by weight of hydrogen gas based on the total weight of the mixture.

[006] The advantages of the present method may include, as a result of injecting hydrogen gas into the liquid hydrocarbon stream, a reduction in the heat of reaction in the production of the reaction product from the liquid hydrocarbon in the first half of the steam cracking furnace, compared with not injecting hydrogen gas into the liquid hydrocarbon stream. For example, the energy absorbed by the process coils may be at least 20% lower than the energy for the equivalent hydrogenated feed. As seen in the present invention, Figure 5 provides an illustration that the addition of 3% by weight of H2 can potentially lead to a 45% energy reduction in the furnace or a 15% reduction compared with the olefin feed stream. Other advantages of the present method include saving both time and money by not hydrotreating the liquid hydrocarbon before it is subjected to the steam cracking process.

[007] The embodiments of the present disclosure further include separating the reaction product from the steam cracking furnace into at least a first fraction that includes at least hydrogen gas and using the first fraction as at least part of the hydrogen gas that is injected into the liquid hydrocarbon stream at or before the inlet of the steam cracking furnace. In one embodiment, the method includes using the first fraction as all of the hydrogen gas that is injected into the liquid hydrocarbon stream at or before the inlet of the steam cracking furnace. For the various Petition 870250087485, dated 09 / 26 / 2025, page 12 / 46 / 22 embodiments, the first fraction may additionally include at least methane, which is injected with hydrogen gas into the liquid hydrocarbon stream at, or before, the inlet of the steam cracking furnace. The embodiments of the present disclosure may further include separating the reaction product into at least the first fraction and a second fraction, wherein the second fraction includes olefinic byproducts of the steam cracking furnace reaction product, and adding the second fraction to the liquid hydrocarbon and hydrogen gas stream at, or before, the inlet of the steam cracking furnace.

[008] The various embodiments may additionally include the removal of impurities from the liquid hydrocarbon before feeding the mixture into the steam cracking furnace inlet. In one embodiment, the removal of impurities from the liquid hydrocarbon may include the extraction of impurities from the liquid hydrocarbon in a liquid-liquid extraction process.

[009] The embodiments of the present disclosure further include a cracking furnace system comprising a liquid-liquid chemical impurity extraction reactor, a steam cracking furnace, and a hydrogen inlet line to supply hydrogen gas to the inlet of the steam cracking furnace. For the various embodiments, the liquid-liquid chemical impurity extraction reactor has a fluid inlet and a fluid outlet. Liquid hydrocarbon with impurities enters the chemical impurity extraction system through the fluid inlet. In the chemical impurity extraction system, at least some of the impurities in the liquid hydrocarbon are separated from the liquid hydrocarbon in a liquid-liquid extraction process to produce a liquid hydrocarbon with reduced impurity content that exits the liquid-liquid chemical impurity extraction reactor through the fluid outlet.The steam cracking furnace is coupled to the fluid outlet of the extraction reactor. Petition 870250087485, dated 09 / 26 / 2025, page 13 / 46 / 22 liquid-liquid chemical impurities. The liquid hydrocarbon with reduced impurity content enters the steam cracking furnace at an inlet without having passed through a hydrotreating plant. The hydrogen inlet line supplies hydrogen gas to the inlet of the steam cracking furnace, where the hydrogen gas mixes with the liquid hydrocarbon with reduced impurity content entering the steam cracking furnace to produce hydrocarbons having a shorter carbon chain length than before entering the steam cracking furnace. For the various embodiments, the steam cracking furnace includes a furnace preheating section formed from a steel alloy that is resistant to hydrogen attack at high temperatures.For the various embodiments, the cracking furnace system additionally includes steam cracking separation systems connected to the steam cracking furnace, wherein the steam cracking separation systems receive hydrocarbons and hydrogen from the steam cracking furnace and separate at least part of the hydrogen (e.g., produce the first fraction) for supply to the steam cracking furnace inlet via the hydrogen inlet line. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic diagram of a cracking furnace system according to an embodiment of the present disclosure.

[0011] Figure 2 is a graph illustrating the changes in ethylene yield from hydrogen gas injected into a liquid hydrocarbon stream according to the present disclosure.

[0012] Figure 3 is a graph illustrating decreases in byproduct production from the injection of hydrogen gas into the olefin feed stream according to the present disclosure.

[0013] Figures 4A and 4B are graphs illustrating the reduction in the formation of carbon disulfide and thiophene from gas injection. Petition 870250087485, dated 09 / 26 / 2025, page 14 / 46 / 22 hydrogen in accordance with the present disclosure.

[0014] Figure 5 is a graph illustrating the heat absorbed in the furnace's radiant coils, supplied as sensible heat and reaction heat, according to embodiments of the present disclosure.

[0015] Figure 6 is a schematic diagram of a cracking furnace system according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0016] The present disclosure provides a method and a system for steam cracking liquid hydrocarbons that helps to eliminate impurities in liquid hydrocarbons while simultaneously improving the saturation of the liquid hydrocarbons without the need for a hydroprocessing system. To achieve this, the present disclosure provides the injection of hydrogen gas into, or immediately before, the inlet of a steam cracking furnace, where the mixture of hydrogen gas and liquid hydrocarbons, as discussed in this document, helps to increase the saturation of the liquid hydrocarbons, thus suppressing reactions that lead to undesirable fouling compounds and increasing ethylene production in the steam cracking system.

[0017] For the various embodiments, the liquid hydrocarbons do not undergo hydroprocessing, as is known in the art, before entering the steam cracking furnace. As used herein, hydroprocessing may include, but is not limited to, hydrotreating and / or hydrocracking as known in the art. As a result, the present disclosure provides steam cracking of what is referred to as non-hydroprocessed liquid hydrocarbons. For brevity, the non-hydroprocessed liquid hydrocarbons of the present disclosure may simply be referred to as liquid hydrocarbons or liquid hydrocarbon in the present invention. As used herein, the liquid hydrocarbons useful for the present disclosure may include, but are not limited to, naphtha, naphtha of Petition 870250087485, dated 09 / 26 / 2025, page 15 / 46 / 22 petroleum, liquefied petroleum gas (LPG), gas oil, pyrolysis oil, for example, from the pyrolysis of plastic waste, and liquid hydrocarbons derived from other natural sources (e.g., crude oil) or industrial processes that can be cracked to produce, among other compounds, ethylene. Preferably, the liquid hydrocarbons useful for the present disclosure include unsaturated hydrocarbons and / or, most preferably, pyrolysis oil, for example, from the pyrolysis of waste plastics. In addition to liquid hydrocarbons, the present disclosure may also be useful in the cracking of other hydrocarbons in a liquid or gaseous state, such as ethane, propane, butanes, pentanes, and kerosene, among others known in the art.

[0018] As discussed in this document, liquid hydrocarbons are known to contain any number of catalyst fouling impurities, such as metals, halogens, chlorine, oxygenates, sulfur, and nitrogen, among others. For example, representative pyrolysis oil can easily contain more than 350 parts per million (ppm) of chlorine (Cl), 30 ppm of bromine (Br), 15 ppm of calcium (Ca), and 15 ppm of silicon (Si). In a further example, the upper limits of heteroatoms in naphtha can be as low as 3 ppm for total organic Cl and 10 ppm for total Cl. These impurities have the potential to poison the catalysts used in the various processes involved in the steam cracking process, as well as damage the steam cracking furnace itself, which is highly undesirable. As a result, impurities need to be reduced or removed from liquid hydrocarbons before they can undergo steam cracking and / or other downstream processes.

[0019] As discussed, the use of a hydroprocessing system can help provide a reduction of impurities in liquid hydrocarbons, while also improving the saturation of liquid hydrocarbons. The disadvantage of using a system is Petition 870250087485, dated 09 / 26 / 2025, page 16 / 46 / 22 hydroprocessing, however, is at high cost in terms of capital expenditure and additional steps required in the steam cracking system (i.e., the increased cost and time required for the use of a hydroprocessing system). Other approaches to reduce heteroatoms in liquid hydrocarbons prior to steam cracking may include chemical extraction processes that use, for example, a hot aqueous solution of sodium hydroxide, as well as polar solvents (e.g., N-methyl-2-pyrrolidone). Such chemical extraction processes, however, do not adequately address the unsaturated components in liquid hydrocarbons. It is typical for liquid hydrocarbons to include unsaturated hydrocarbons, such as alkenes, dikelens, and aromatics, which can contribute to reduced ethylene production and increased coking and / or fouling in the steam cracking furnace.

[0020] As understood, the presence of unsaturated components in liquid hydrocarbons subjected to steam cracking can lead to a decrease in desired products (e.g., ethylene) and an increase in undesired products that can lead to fouling in the steam cracking system. For example, pyrolysis oil derived from pyrolyzed polyethylene may contain more than 40% by weight of olefins in the light distillate (e.g., 54 to 208 °C) and almost 50% by weight in the middle distillate (e.g., 200 to 375 °C). An acceptable upper limit for olefins in a steam cracking furnace is, however, typically about 1% by volume. One reason for this limit is that, in the steam cracking furnace, olefins are known to produce more coke in the radiant coils along with the downstream transfer line heat exchanger (TLE) than the equivalent saturated hydrocarbon.In fact, it is known that coke levels in the first half of the steam cracking furnace coil system can be practically 90% of the coke levels in the second half of the coil system. This suggests that... Petition 870250087485, dated 09 / 26 / 2025, page 17 / 46 / 22 Olefin-induced coking begins at some of the lower temperatures in the steam cracking furnace. Another issue is that steam cracking olefins typically result in lower ethylene yield than equivalent saturated hydrocarbons. This difference in ethylene yield can be attributed to the increased formation of more unsaturated species such as acetylene, propadiene, butadiene, benzene, and styrene.

[0021] The present disclosure helps to overcome these shortcomings in the art by providing a method and system for steam cracking that helps to eliminate impurities in liquid hydrocarbons, such as pyrolysis oil, while simultaneously improving the saturation of liquid hydrocarbons without the large capital investment of a hydroprocessing system for the steam cracking system.For this purpose, the present disclosure provides a method for supplying a stream of liquid hydrocarbon to an inlet of a steam cracking furnace and injecting hydrogen gas into the liquid hydrocarbon stream at, or before, the inlet of the steam cracking furnace to produce a mixture of the liquid hydrocarbon and hydrogen gas. The liquid hydrocarbon in the mixture is subjected to steam cracking to produce a reaction product that includes hydrocarbons having shorter carbon chain lengths than before entering the steam cracking furnace. The method does not comprise hydroprocessing the liquid hydrocarbon prior to steam cracking. For the various embodiments, the reaction product includes at least ethylene.

[0022] Figure 1 provides an illustration of an embodiment of a cracking furnace system 100 of the present disclosure. As illustrated, the cracking furnace system 100 includes a steam cracking furnace 102 having an inlet 104 and an outlet 106. A stream 108 of a liquid hydrocarbon is supplied to the inlet 104 of the steam cracking furnace 102 through line 110. As used herein, a line may include Petition 870250087485, dated 09 / 26 / 2025, page 18 / 46 / 22 piping or a conduit that is sufficiently designed and installed, as is known in the art, to enable the transport of the material being moved between the process of the present disclosure.

[0023] As illustrated, the liquid hydrocarbon stream 108 enters the inlet 104 of the steam cracking furnace 102 without having passed through a hydrotreating plant. Furthermore, for the various embodiments, the liquid hydrocarbon stream 108 entering the inlet 104 of the steam cracking furnace 102 has not been subjected to any hydroprocessing step before entering the inlet 104.

[0024] The cracking furnace system 100 additionally includes a hydrogen inlet line 112 to supply hydrogen to inlet 104 of the steam cracking furnace 102. For the various embodiments, the hydrogen supplied to inlet 104 of the steam cracking furnace 102 is in a gaseous state and may be supplied as the only gas supplied to inlet 104 of the steam cracking furnace 102 via 110 (e.g., pure hydrogen gas is supplied to inlet 104). In an alternative embodiment, the hydrogen supplied to inlet 104 of the steam cracking furnace 102 is part of a gas mixture that includes minor hydrocarbons (e.g., methane in a first fraction as discussed in this document).

[0025] For the various embodiments, hydrogen gas from the hydrogen inlet line 112 is injected into the liquid hydrocarbon stream 108 at or before inlet 104 of the steam cracking furnace 102. In one embodiment, hydrogen gas from the hydrogen inlet line 112 is injected into the liquid hydrocarbon stream 108 at inlet 104 of the steam cracking furnace 102. In an alternative embodiment, hydrogen gas from the hydrogen inlet line 112 is injected into the liquid hydrocarbon stream 108 before inlet 104 of the steam cracking furnace 102, where there are no processing and / or processing equipment. Petition 870250087485, dated 09 / 26 / 2025, page 19 / 46 / 22 located between where hydrogen gas from the hydrogen inlet line 112 is injected into the liquid hydrocarbon stream 108 and the inlet 104 of the steam cracking furnace 102.

[0026] For the various embodiments, hydrogen gas from hydrogen inlet line 112 injected into liquid hydrocarbon stream 108 produces a mixture of liquid hydrocarbon and hydrogen gas. For the various embodiments, the mixture includes 0.1 percent by weight (% by weight) to 10% by weight of hydrogen gas based on the total weight of the mixture. In one additional embodiment, the mixture includes 5% by weight to 7% by weight of hydrogen gas based on the total weight of the mixture. In another embodiment, the mixture includes 0.1% by weight to 1% by weight of hydrogen gas based on the total weight of the mixture. In one specific embodiment, the mixture includes 6% by weight of hydrogen gas based on the total weight of the mixture.The mixture of liquid hydrocarbon and hydrogen gas enters the steam cracking furnace 102, where, under the operating conditions of the steam cracking furnace 102 as discussed in this document, the mixture of liquid hydrocarbon and hydrogen gas mixes with dilution steam to undergo reactions that produce a reaction product that includes hydrocarbons having shorter carbon chain lengths than before entering the steam cracking furnace. For the various embodiments, the dilution steam may have a pressure of 5 to 15 bar (500 to 1500 kilopascals) and a temperature from the corresponding saturation level temperature for the given pressure to 200 °C superheated. For the various embodiments, the method of the present disclosure does not comprise hydroprocessing the liquid hydrocarbon prior to steam cracking. For example, the method does not comprise hydrotreating the liquid hydrocarbon prior to steam cracking.

[0027] For the various embodiments, the compounds in the reaction products include saturated hydrocarbons produced from Petition 870250087485, dated 09 / 26 / 2025, page 20 / 46 / 22 unsaturated hydrocarbons (e.g., olefinic hydrocarbons) that were initially part of the liquid hydrocarbons entering the steam cracking furnace 102. More specifically, the reaction products may include, for example, hydrogen and C1 to C5 hydrocarbons, wherein the C1 to C5 hydrocarbons may include, among other compounds, methane, ethylene, propylene, butanes, butenes, pentanes, and pentenes, as known in the art. For the various embodiments, the reaction product includes at least ethylene. For example, the reaction product stream may include about 30 to 40% by weight of ethylene in the reaction product, wherein the percentage values ​​by weight are based on the total weight of the reaction product.The reaction products may also include linear, branched, and cyclic hydrocarbons, including aromatic hydrocarbons, with carbon numbers of C4 and higher (e.g., C5 and C6).

[0028] As is known in the art, the products produced in the reaction depend on several factors, including the composition of the liquid hydrocarbon, the hydrocarbon / vapor ratio, and the cracking temperature and residence time in the furnace. For the various embodiments, the steam cracking furnace 102, as known in the art, operates to produce at least ethylene and propylene from the hydrocarbon stream 108 (e.g., liquid hydrocarbons 108) and steam. As known in the art, the steam cracking furnace 102 includes two main components, the first of which is a coil bundle where the cracking reactions occur, and the second is a furnace that provides the heat necessary to crack the liquid hydrocarbons 108 in the mixture of the present disclosure and the steam in the coil bundle. These reactions can occur in coils located in a radiant section of the steam cracking furnace 102.The temperatures of the steam cracking furnace 102 in this radiant section can range from 700 °C to 950 °C (for example, 800 to 870 °C) and higher depending on the raw material. Petition 870250087485, dated 09 / 26 / 2025, page 21 / 46 / 22 used. The residence time for the mixture of the present disclosure and the steam in the radiant section can be from 1 millisecond to 5 seconds, wherein the residence time is selected so as to be sufficient to convert the hydrocarbons into the reaction products, which include ethylene and propylene, but not so long as to allow the production of substantial quantities of coke. Catalysts, as they are known in the art, can also be used in the steam cracking furnace 102 to achieve higher conversion rates of the liquid hydrocarbons.

[0029] The steam cracking furnace 102 additionally includes a furnace preheating section, which may contain gas-gas heat exchangers, as known in the art. The gas-gas heat exchangers can be used to preheat the steam and the mixture, according to the present disclosure, passing through the coils. This preheating procedure serves to increase the energy efficiency of the process, thereby reducing fuel consumption and operating costs. For the various embodiments, the furnace preheating section can be formed from a steel alloy that is resistant to hydrogen attack at high temperatures. Examples of suitable steel alloys include 304H, 800H, 25Cr35Ni cast.

[0030] Once the reaction products leave the steam cracking furnace 102, through outlet 106, they pass through line 114 to be rapidly cooled in a transfer line exchanger (TLE) 116. The TLE 116, as known in the art, serves not only to cool the reaction products, but also to recover heat from the reaction products and steam to produce high-pressure steam for further use in another process of the cracking furnace system 100 (e.g., driving turbines to compress the reaction products and operating refrigeration compressors for ethylene and propylene).

[0031] The method of the present disclosure additionally includes separating Petition 870250087485, dated 09 / 26 / 2025, page 22 / 46 / 22 the reaction product in different fractions for use with the cracking furnace system 100 and, in particular, the steam cracking furnace 102 of the cracking furnace system 100, as discussed in this document. As illustrated in Figure 1, the reaction products from TCT 116 enter steam cracking separation systems 118 connected to the steam cracking furnace 102. The steam cracking separation systems 118 receive the hydrocarbons from the reaction products and hydrogen from the steam cracking furnace 102 and separate at least part of the hydrogen to supply the inlet 104 of the steam cracking furnace 102 through the hydrogen inlet line 112.

[0032] Steam cracking separation systems 118 may additionally include a variety of separation units (e.g., distillation units, compressors, coolers, and separation towers) as known in the art to create hydrogen fractions and hydrocarbon fractions separated from the reaction products. For example, steam cracking separation systems 118 may form at least a first fraction that includes at least hydrogen gas present in the reaction products. To achieve this, steam cracking separation systems 118 may include a demethanizing unit or tower, as known in the art, to produce the first fraction consisting of most, if not all, of the hydrogen and methane present in the reaction product stream.If desired, the top stream from the demethanizer tower can be compressed, dried, and cryogenically treated to separate hydrogen from methane, as is known in the art. It is also possible to use a pressure swing absorption (PSA) unit to separate hydrogen from the reaction products.

[0033] For the various embodiments, the first fraction can be used to supply hydrogen to the hydrogen inlet line 112. For example, the Petition 870250087485, dated 09 / 26 / 2025, page 23 / 46 / 22 The first fraction can be used as at least part of the hydrogen gas that is injected into the liquid hydrocarbon stream 108 at or before the inlet 104 of the steam cracking furnace 102. In one embodiment, the first fraction can be used as all of the hydrogen gas that is injected into the liquid hydrocarbon stream 108 at or before the inlet 104 of the steam cracking furnace 102. In a further embodiment, the first fraction can additionally include at least methane that is injected with the hydrogen gas into the liquid hydrocarbon stream 108 at or before the inlet 104 of the steam cracking furnace 102.

[0034] The embodiments of the present disclosure may further include separating the reaction product into at least a second fraction that includes olefinic byproducts from the reaction product of the steam cracking furnace. The olefinic byproducts may include C4 and larger olefinic hydrocarbons, including aromatic and non-aromatic olefins. To achieve this, for example, a bottom stream from the demethanizer unit may be fed to a deethanizer unit or tower, as is known in the art. The top stream from the deethanizer tower may consist of the C2 products (e.g., ethane and ethylene) from the reaction products. The C2 products may then proceed to a C2 splitter, where the ethylene may be removed from the top stream of the C2 splitter and the ethane from the bottom of the C2 splitter may be recycled to the steam cracking furnace 102 as at least a portion of the second fraction to be cracked again.For the various methods, the second fraction can be added to the liquid hydrocarbon and hydrogen gas stream at, or before, the inlet of the steam cracking furnace.

[0035] For the various embodiments, the bottom stream from the deethanizing unit may go to a depropanizing unit or tower, where the top stream from the depropanizing tower consists of the C3 hydrocarbons from the reaction products, which may be processed and split, as is Petition 870250087485, dated 09 / 26 / 2025, page 24 / 46 / 22 known in the art, in propylene and propane, wherein the propane can be sent back to the steam cracking furnace 102 for cracking (for example, as another portion of the second fraction added to the liquid hydrocarbon and hydrogen gas stream at, or before, the steam cracking furnace inlet) or for use as fuel. Finally, the bottom stream from the depropane unit can be fed to a debutane unit, where the top stream of the debutane unit includes the C4 reaction products. The bottom stream of the debutane unit (light pyrolysis gasoline) consists of the remaining reaction products that are C5 or heavier.

[0036] Regarding the cracking furnace system and method of the present disclosure, an internally developed kinetic modeling tool was used to simulate the formation of byproducts from saturated hydrocarbons from steam cracking as a function of steam cracking of their olefinic counterparts. The kinetic modeling tool was developed based on an initial estimate of the thermodynamic and rate kinetic parameters for the thousands of elementary reactions involved in the steam cracking of hydrocarbon components, including ethane, propane, butanes, pentane, hexane, and heptane (Wang et al., Kinetic Study of Thermal Decomposition of N,N-Diethylhydroxylamine (DEHA) in Steam Crackers, 29th Ethylene Producers' Conference, San Antonio, March 27-30, 2017).The conditions for the simulation included a dilution steam ratio of 0.3; an inlet coil temperature of 630 °C; and an outlet coil temperature of 868 °C, wherein the process conditions for the base case (n-hexane) resulted in 31.4% ethylene (by weight, on a dry basis). The olefin components are steam cracking products of the aforementioned saturated hydrocarbons, so the model also enabled steam cracking simulations of olefin feed streams. Petition 870250087485, dated 09 / 26 / 2025, page 25 / 46 / 22

[0037] The simulation results above indicated that the different reaction products could be attributed to the activation energy for dimerization as a function of the cracking activation energy. If cyclization or dimerization reactions occur in the heating phase of the reactor, then the ethylene yield is suppressed. Furthermore, olefin processing increases the formation of secondary products in the cooler section of the radiant coil. Therefore, it would be relevant to suppress these reactions and avoid losses in ethylene selectivity.

[0038] Figure 2 helps illustrate that injecting hydrogen gas into liquid hydrocarbons (e.g., C6) at or before the inlet to the steam cracking furnace, as provided in this document, helps increase the ethylene yield from 26.5 to 36.6%, with the percentage by weight of hydrogen gas based on the total weight of the mixture. Additionally, it was observed that the butadiene yield also decreased, which may indicate that the addition of hydrogen gas, as provided in this document, could suppress the production of fouling precursors. Similarly, with increased addition of hydrogen gas to the olefin feed, there is a decrease in the production of other byproducts, including acetylene, vinylacetylene, methylacetylene and propadiene (MAPD), benzene, and styrene, as shown in Figure 3.

[0039] Other benefits that can be obtained from the present disclosure are that the addition of hydrogen should suppress the reactions that convert dimethyl disulfide into carbon disulfide and thiophene. In other simulations with the kinetic modeling tool above, the formation of carbon disulfide and thiophene was reduced when hydrogen gas was injected with crude liquid C6 hydrocarbons, where the results are seen in Figures 4A and 4B.

[0040] An additional benefit of the present disclosure is that relatively less energy is required to break down hydrocarbons. Petition 870250087485, dated 09 / 26 / 2025, page 26 / 46 / 22 liquids when hydrogen is added to form the mixture, as discussed in this document. Without adhering to theory, it is believed that the addition of hydrogen, as discussed in this document, inhibits other dehydrogenation reactions and thus reduces the endothermicity of the process. Figure 5 illustrates this point, where the heat absorbed in the furnace's radiant coils is supplied as sensible heat and heat of reaction. Furthermore, the injection of hydrogen gas into the liquid hydrocarbon stream results in a reduction of the heat of reaction in the production of the reaction product from the liquid hydrocarbon in the first half of the steam cracking furnace compared to not injecting hydrogen gas into the liquid hydrocarbon stream.For example, the energy absorbed by the process coils in the radiant section of the steam cracking furnace will be at least 20% lower than the energy for equivalent hydrogenated feed. Furthermore, as seen in Figure 5, there is an illustration that the addition of 3% by weight of H2 can potentially lead to a 45% energy reduction in the furnace, or a 15% reduction compared to the olefin feed stream.

[0041] The various embodiments may additionally include the removal of impurities from the liquid hydrocarbon before feeding the mixture to the inlet of the steam cracking furnace. In one embodiment, the removal of impurities from the liquid hydrocarbon may include the extraction of impurities from the liquid hydrocarbon in a liquid-liquid extraction process. For example, with reference to Figure 6, a cracking furnace system is shown as illustrated and discussed in relation to Figure 1, the discussion of which is not repeated in the present invention but is included by way of reference to the discussion above, wherein the cracking furnace system additionally includes a liquid-liquid extraction reactor for chemical impurities to remove impurities from the liquid hydrocarbon before feeding the mixture to the inlet of the steam cracking furnace. As Petition 870250087485, dated 09 / 26 / 2025, page 27 / 46 / 22 discussed in this document, the removal of impurities from liquid hydrocarbon may include the extraction of impurities from the liquid hydrocarbon in a liquid-liquid extraction process. Furthermore, it is possible to remove impurities using adsorbents as are known in the art. Other suitable examples of suitable liquid hydrocarbons include, but are not limited to, those formed from polyethylene that has undergone a pyrolysis process; in this case, no pretreatment may be necessary.

[0042] As illustrated in Figure 6, just one example of other possible designs, as discussed in this document, the cracking furnace system 600 includes a chemical impurity liquid-liquid extraction reactor 620 having a fluid inlet 622 and a fluid outlet 624. As discussed in this document, the liquid hydrocarbon has impurities that enter the chemical impurity extraction system 620 through the fluid inlet 622, wherein at least some of the impurities in the liquid hydrocarbon are separated from the liquid hydrocarbon in a liquid-liquid extraction process to produce a liquid hydrocarbon with reduced impurity content. The liquid hydrocarbon with reduced impurity content then exits the chemical impurity liquid-liquid extraction reactor 620 through the fluid outlet 624.

[0043] For the various embodiments, examples of the chemical impurity liquid-liquid extraction reactor 620 may include those found in document WO 2022 / 079057 Al, which is incorporated herein by reference in its entirety. In summary, the liquid-liquid extraction process involves contacting the liquid hydrocarbon with an extraction solvent a) containing one or more heteroatoms and subjecting the liquid hydrocarbon to liquid-liquid extraction with the extraction solvent a), resulting in a first stream of liquid hydrocarbons with reduced impurity content exiting the liquid-liquid extraction reactor. Petition 870250087485, dated 09 / 26 / 2025, page 28 / 46 / 22 chemical impurities 620 through the outlet to fluid 624 and a second stream comprising extraction solvent a), heteroatom containing organic compounds; b) mix at least part of the second stream resulting from step a) with a mixture segregation solvent b) containing one or more heteroatoms and having a miscibility in heptane that is less than the miscibility of extraction solvent a) in heptane and separate the resulting mixture into a first stream comprising organic compounds containing heteroatoms and a second stream comprising extraction solvent a) and mixture segregation solvent b); c) place at least part of the second stream resulting from step b) in contact with a membrane and recover a permeate stream comprising the mixture segregation solvent b) and a retentate stream comprising extraction solvent a);d) recycle at least part of the extraction solvent a) from the retentate stream resulting from step c) to step a).

[0044] For the various embodiments, the extraction solvent a) comprises ammonia or one or more organic solvents selected from the group consisting of diols and triols, including monoethylene glycol (MEG), monopropylene glycol (MPG), any isomer of butanediol and glycerol; glycol ethers, including oligoethylene glycols, including diethylene glycol, triethylene glycol and tetraethylene glycol, and monoalkyl ethers thereof, including diethylene glycol ethyl ether; amides, including N-alkylpyrrolidone, wherein the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including N-methylpyrrolidone (NMP), formamide and di- and monoalkyl formaides and acetamides, wherein the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethyl formamide (DMF), methyl formamide and dimethyl acetamide; dialkyl sulfoxide, wherein the alkyl group may contain 1 to 8 or 1 to 3 carbon atoms, including dimethyl sulfoxide (DMSO); sulfones, including sulfolane; N-formyl morpholine (NFM);furan ring containing components and derivatives thereof, including furfural, 2-methylfuran; Petition 870250087485, dated 09 / 26 / 2025, page 29 / 46 / 22 furfuryl alcohol and tetrahydrofurfuryl alcohol; hydroxy esters, including lactates, including methyl and ethyl lactate; trialkyl phosphates, including triethyl phosphate; phenolic compounds, including phenol and guaiacol; benzyl alcoholic compounds, including benzyl alcohol; amine compounds, including ethylenediamine, monoethanolamine, diethanolamine and triethanolamine; nitrile compounds, including acetonitrile and propionitrile; trioxane compounds, including 1,3,5-trioxane; carbonate compounds, including propylene carbonate and glycerol carbonate; and cycloalkanone compounds, including dihydrolevoglucosenone. For the various embodiments, the mixture segregation solvent b) may comprise one or more solvents selected from the group consisting of water and the solvents from the group of solvents as defined for the extraction solvent a).

[0045] As seen and discussed in relation to Figure 1, the steam cracking furnace 602 is coupled to the fluid outlet 624 of the liquid-liquid chemical impurity extraction reactor 620. The liquid hydrocarbon with reduced impurity content enters the steam cracking furnace 602 at inlet 604 without having passed through a hydrotreating plant or any hydroprocessing process. The cracking furnace system 600 additionally includes the hydrogen inlet line 612 to supply hydrogen gas to inlet 604 of the steam cracking furnace 602. As discussed in this document, the hydrogen gas mixes with the liquid hydrocarbon with reduced impurity content entering the steam cracking furnace 602 to produce hydrocarbons having a shorter carbon chain length than before entering the steam cracking furnace.The reaction products leave the steam cracking furnace 602, via outlet 606 through line 614, to be rapidly cooled in the TLE 616. The reaction product is then separated into different fractions for use with the cracking furnace system 600 and, in particular, the steam cracking furnace. Petition 870250087485, dated 09 / 26 / 2025, page 30 / 46 / 22 602 of the cracking furnace system 600, as discussed in this document. As illustrated in Figure 6, the reaction products of TLE 616 enter the steam cracking separation systems 618 connected to the steam cracking furnace 602, where the reaction products are separated into the various fractions for use with the present disclosure as discussed above in relation to Figure 1. Petition 870250087485, dated 09 / 26 / 2025, page 31 / 46

Claims

1 / 3 CLAIMS 1. A method, characterized in that it comprises: supplying a stream of liquid hydrocarbon to an inlet of a steam cracking furnace; injecting hydrogen gas into the liquid hydrocarbon stream at, or before, the inlet of the steam cracking furnace to produce a mixture of the liquid hydrocarbon and hydrogen gas; and steam cracking the liquid hydrocarbon in the mixture to produce a reaction product that includes hydrocarbons having carbon chain lengths shorter than before entering the steam cracking furnace; wherein the method does not comprise hydroprocessing the liquid hydrocarbon prior to steam cracking.

2. A method according to claim 1, characterized in that the mixture includes from 0.1 percent by weight (% by weight) to 10 percent by weight of hydrogen gas based on the total weight of the mixture; or wherein the mixture includes from 0.1 percent by weight to 1 percent by weight of hydrogen gas based on the total weight of the mixture.

3. A method according to either of claims 1 and 2, characterized in that the injection of hydrogen gas into the liquid hydrocarbon stream results in a reduction of the heat of reaction in the production of the reaction product from the liquid hydrocarbon in the first half of the steam cracking furnace compared with the non-injection of hydrogen gas into the liquid hydrocarbon stream.

4. A method according to either of claims 1 and 2, characterized in that the method does not comprise hydrotreating the liquid hydrocarbon prior to steam cracking.

5. Method according to any one of claims 1 to 2, characterized in that it further includes separating the reaction product into at least a first fraction that includes at least hydrogen gas; and using the first fraction as at least part of the hydrogen gas that is injected into the liquid hydrocarbon stream at or before the inlet of the steam cracking furnace; or further including using the first fraction as all of the hydrogen gas that is injected into the liquid hydrocarbon stream at or before the inlet of the steam cracking furnace; or the first fraction further including at least methane that is injected with the hydrogen gas into the liquid hydrocarbon stream at or before the inlet of the steam cracking furnace.

6. A method according to any one of claims 1 and 2, characterized in that it further includes separating the reaction product into at least a second fraction that includes olefinic byproducts of the steam cracking furnace reaction product; and adding the second fraction to the liquid hydrocarbon and hydrogen gas stream at or before the inlet of the steam cracking furnace.

7. A method according to any one of claims 1 to 2, characterized in that it additionally includes removing impurities from the liquid hydrocarbon before feeding the mixture into the steam cracking furnace; or wherein the removal of impurities from the liquid hydrocarbon includes extracting impurities from the liquid hydrocarbon in a liquid-liquid extraction process.

8. A method according to either of claims 1 and 2, characterized in that the reaction product includes at least ethylene.

9. Cracking furnace system, characterized in that it comprises: Petition 870250087485, dated 09 / 26 / 2025, page 45 / 46 3 / 3 a liquid-liquid extraction system for chemical impurities having a fluid inlet and a fluid outlet, wherein the liquid hydrocarbon having impurities enters the chemical impurity extraction system through the fluid inlet and at least some of the impurities in the liquid hydrocarbon are separated from the liquid hydrocarbon in a liquid-liquid extraction process to produce a liquid hydrocarbon with a reduced impurity content that exits the liquid-liquid extraction reactor for chemical impurities through the fluid outlet; A steam cracking furnace is coupled to the fluid outlet of the liquid-liquid extraction reactor for chemical impurities, wherein the liquid hydrocarbon with a reduced impurity content enters the steam cracking furnace through an inlet without having passed through a hydrotreating plant;and a hydrogen inlet line to supply hydrogen gas to the steam cracking furnace inlet, wherein the hydrogen gas mixes with the liquid hydrocarbon with reduced impurity content that enters the steam cracking furnace to produce hydrocarbons having a shorter carbon chain length than before entering the steam cracking furnace.

10. Cracking furnace system according to claim 9, characterized in that the steam cracking furnace includes a furnace preheating section formed from a steel alloy that is resistant to hydrogen attack at high temperatures; or additionally including a steam cracking separation system connected to the steam cracking furnace, wherein the steam cracking separation system receives hydrocarbons and hydrogen from the steam cracking furnace and separates at least part of the hydrogen to supply the inlet of the steam cracking furnace through the hydrogen inlet line. Petition 870250087485, dated 09 / 26 / 2025, pp. 46 / 46

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