Oxidative dehydrogenation with water-gas shift reaction

Abstract

The present disclosure relates to hydrocarbon production processes including oxidative dehydrogenation of ethane-containing feed streams and reaction of carbon monoxide produced thereby with water to produce hydrogen and carbon dioxide.

Description

[0001]OXIDATIVE DEHYDROGENATION WITH WATER-GAS SHIFT REACTION TECHNICAL FIELD The present disclosure relates to hydrocarbon production processes including oxidative dehydrogenation integrated with a water-gas shift reaction. BACKGROUND ART Catalytic oxidative dehydrogenation of alkanes into corresponding alkenes is an alternative to steam cracking. In contrast to steam cracking, oxidative dehydrogenation (ODH) can operate at lower temperatures and generally does not produce coke. For ethylene production, oxidative dehydrogenation can provide a greater selectivity for ethylene than steam cracking. Carbon monoxide produced by oxidative dehydrogenation of ethane is typically combusted, which produces carbon dioxide, a greenhouse gas. Additionally, related hydrocarbon production processes, including certain processes for preparing an oxidative dehydrogenation feedstock, require hydrogen, which is typically provided by steam methane reforming, which produces carbon dioxide. Accordingly, there is a need for improved, integrated low-carbon oxidative dehydrogenation processes. SUMMARY OF INVENTION Provided in the present disclosure is a method of producing hydrocarbons. The method includes contacting an oxidative dehydrogenation feed stream including C2H6and an oxidant stream including O2 with an oxidative dehydrogenation catalyst to form a dehydrogenated stream including C2H4, CO2, CO, and H2O; and contacting a water-gas shift feed stream including H2O and at least a portion of the dehydrogenated stream including CO with a water-gas shift catalyst to form a shifted stream including H2and CO2. In some embodiments, the dehydrogenated stream further includes C2H6, O2, or both. In some embodiments, the oxidative dehydrogenation feed stream further includes a diluent, and the dehydrogenated stream further includes the diluent. In some embodiments, the diluent includes H2O, CH4, CO2, Ar, He, N2, or any combination thereof. In some embodiments, the diluent includes CH4, N2, or both. In some embodiments, the method further includes separating the dehydrogenated stream to form a first separated stream including H2O and a second separated stream including C2H4, CO2, and CO, and the water-gas shift feed stream includes at least a portion of the second separated stream including CO. In some embodiments, the second separated stream further includes C2H6, O2, a diluent, or any combination thereof. In some embodiments, the dehydrogenated stream further includes acetic acid; separating the dehydrogenated stream includes contacting the dehydrogenated stream with a scrubbing liquid; and the first separated stream further includes acetic acid and the scrubbing liquid. In some embodiments, the dehydrogenated stream further includes acetic acid; separating the dehydrogenated stream includes cooling the dehydrogenated stream to a temperature lower than a dew point of acetic acid; and the first separated stream further includes acetic acid. In some embodiments, the water-gas shift feed stream includes at least a portion of the first separated stream including H2O. In some embodiments, the first separated stream further includes acetic acid; the method further includes separating the first separated stream to form an acetic acid-rich stream including acetic acid and a water-rich stream including H2O; and the first separated stream includes at least a portion of the water-rich stream including H2O. In some embodiments, the method further includes separating the second separated stream to form a third separated stream including CO2 and a fourth separated stream including C2H4 and CO, and the water-gas shift feed stream includes at least a portion of the fourth separated stream including CO. In some embodiments, the fourth separated stream further includes C2H6, a diluent, or any combination thereof. In some embodiments, the second separated stream includes contacting the second separated stream with an amine solvent. In some embodiments, the method further includes separating the fourth separated stream to form a fifth separated stream including C2H4 and a sixth separated stream including CO, and the water-gas shift feed stream includes at least a portion of the sixth separated stream including CO. In some embodiments, the fifth separated stream further includes C2H6. In some embodiments, the sixth separated stream further includes a diluent. In some embodiments, separating the fourth separated stream includes cryogenically distilling the fourth separated stream. In some embodiments, the oxidant stream includes air, and the water-gas shift feed stream further includes N2. In some embodiments, the water-gas shift feed stream further includes CH4. In some embodiments, the method further includes combusting at least a portion of the shifted stream including H2 and CO2 to produce thermal energy and CO2; and capturing at least a portion of the CO2. In some embodiments, the method further includes using at least a portion of the thermal energy to heat a steam cracking feed stream including one or more C2–C4 hydrocarbons and H2O to form a cracked stream including C2H6. In some embodiments, the method further includes separating the shifted stream to form a hydrogen-rich stream including H2 and a carbon dioxide-rich stream including CO2. In some embodiments, separating the shifted stream includes contacting the shifted stream with a membrane. In some embodiments, separating the shifted stream includes contacting the shifted stream with an amine solvent. In some embodiments, the method further includes contacting a hydrocracking feed stream including a pyrolysis oil and a portion of the hydrogen-rich stream including H2with a hydrocracking catalyst to form a hydrocracked stream including one or more C2–C4 hydrocarbons. In some embodiments, the method further includes contacting a hydrotreating feed stream including a raw pyrolysis oil and a portion of the hydrogen-rich stream including H2with a hydrotreating catalyst to form a hydrotreated stream including a treated pyrolysis oil, and the hydrocracking feed stream includes at least a portion of the hydrotreated stream including the treated pyrolysis oil. In some embodiments, the method further includes contacting a hydrogenation feed stream including an unsaturated hydrocarbon having a first degree of unsaturation and a portion of the hydrogen-rich stream including H2with a hydrogenation catalyst to form a hydrogenated stream including a saturated hydrocarbon, a second unsaturated hydrocarbon having a second degree of unsaturation, or both, and the second degree of unsaturation is less than the first degree of unsaturation. In some embodiments, the unsaturated hydrocarbon includes C2H2, and the hydrogenated stream includes C2H6, C2H4, or both. In some embodiments, the unsaturated hydrocarbon includes styrene, and the hydrogenated stream includes ethylbenzene. In some embodiments, the method further includes storing at least a portion of the hydrogen-rich stream including H2. In some embodiments, the oxidative dehydrogenation feed stream further includes at least a portion of the carbon dioxide-rich stream including CO2. Also provided in the present disclosure is a system for producing hydrocarbons. The system includes an oxidative dehydrogenation reactor configured to contact an oxidative dehydrogenation feed stream including C2H6 and an oxidant stream including O2 with an oxidative dehydrogenation catalyst to form a dehydrogenated stream including C2H4, CO2, CO, and H2O; and a water-gas shift reactor configured to contact a water-gas shift feed stream including H2O and at least a portion of the dehydrogenated stream including CO with a water-gas shift catalyst to form a shifted stream including H2and CO2. In some embodiments, the system further includes a separator configured to separate the shifted stream to form a hydrogen-rich stream including H2and a carbon dioxide-rich stream including CO2. In some embodiments, the separator includes a membrane separator configured to contact the shifted stream with a membrane. In some embodiments, the separator includes an amine tower configured to contact the shifted stream with an amine solvent. In some embodiments, the amine tower is further configured to separate CO2from the dehydrogenated stream. In some embodiments, the system further includes a hydrocracking reactor configured to contact a hydrocracking feed stream including a pyrolysis oil and a portion of the hydrogen-rich stream including H2with a hydrocracking catalyst to form a hydrocracked stream including one or more C2–C4 hydrocarbons. In some embodiments, the system further includes a hydrotreating reactor configured to contact a hydrotreating feed stream including a raw pyrolysis oil and a portion of the hydrogen-rich stream including H2 with a hydrotreating catalyst to form a hydrotreated stream including a treated pyrolysis oil, and the hydrocracking feed stream includes at least a portion of the hydrotreated stream including the treated pyrolysis oil. In some embodiments, the system further includes a hydrogenation reactor configured to contact a hydrogenation feed stream including an unsaturated hydrocarbon having a first degree of unsaturation and a portion of the hydrogen-rich stream including H2with a hydrogenation catalyst to form a hydrogenated stream including a saturated hydrocarbon, a second unsaturated hydrocarbon having a second degree of unsaturation, or both, and the second degree of unsaturation is less than the first degree of unsaturation. BRIEF DESCRIPTION OF DRAWINGS Figure 1 is a schematic diagram of a system for producing hydrocarbons in accordance with certain embodiments described herein. Figure 2 is a process flow diagram of a method for producing hydrocarbons. Figure 3 is a flowsheet of a simulation of a water-gas shift reaction described herein. Figure 4 is a schematic of an oxidative dehydrogenation reactor configuration described herein. DESCRIPTION OF EMBODIMENTS The present disclosure relates to methods and systems for hydrocarbon production by oxidative dehydrogenation integrated with water-gas shift reaction. The methods and systems described herein provide a process for producing hydrocarbons including oxidative dehydrogenation of ethane (C2H6) and water-gas shift reaction of carbon monoxide (CO) byproduct thereof to form a stream including hydrogen (H2) and carbon dioxide (CO2) that can be used, for example, in an oxy-fuel combustion process. The stream can also be suitable for membrane separation, which provides highly pure H2 useful, for example, in preparing the oxidative dehydrogenation feedstock, and CO2useful, for example, as a diluent / reactant in the oxidative dehydrogenation process. In some embodiments, the produced CO2can be more easily captured, as compared to that resulting from combustion of CO in corresponding methods and systems lacking an integrated water-gas shift reaction. Figure 1 is a schematic illustration of a system 100 for producing hydrocarbons in accordance with certain embodiments of the present disclosure. The system includes an oxidative dehydrogenation reactor 102, separators 104, 106, 108, 112, and a water-gas shift reactor 110. Liquid and gaseous streams and materials used in the system represented in Figure 1 can be directed and transferred through suitable transfer lines, conduits, and piping. Particular elements may be physically juxtaposed and, where appropriate, may have flexible regions, rigid regions, or a combination of both. In directing streams of compounds, intervening apparatuses and / or optional treatments may be included. For example, pumps, valves, manifolds, gas and liquid flow meters and distributors, sampling and sensing devices, and other equipment (e.g., for monitoring, controlling, adjusting, and / or diverting pressures, flows and other operating parameters) can be included in the system. An oxidant stream 101 including oxygen (O2) and an oxidative dehydrogenation feed stream 103 including C2H6are directed to the oxidative dehydrogenation reactor 102 including an oxidative dehydrogenation catalyst (not shown). Suitable configurations of the oxidative dehydrogenation reactor 102 are known in the art. For example, the oxidative dehydrogenation reactor 102 can include one shell-and-tube reactor, or two or more shell- and-tube reactors (e.g., in series and / or in parallel). In some embodiments, the oxidant stream 101, the oxidative dehydrogenation feed stream 103, or both include a diluent. In some examples, the diluent can help to control the heat of reaction released. Certain diluents can be reactive, and can change the selectivity of C2H4. The diluent can include, for example, steam (H2O), methane (CH4), CO2, nitrogen (N2), helium (He), argon (Ar), and the like. In some embodiments, the diluent includes H2O, CO2, or both. In some embodiments, the diluent includes N2, for example, where the oxidant stream includes air. In some embodiments, the diluent includes CH4, for example, where the oxidative dehydrogenation stream 103 includes one or more typical ethane pipeline contaminants. In some embodiments, the oxidative dehydrogenation feed stream 103 includes the product of a hydrocracking process. For example, in some embodiments, the oxidative dehydrogenation feed stream 103 includes the product of hydrocracking a pyrolysis oil, e.g., derived from catalytic pyrolysis of a plastic. In some embodiments, the oxidative dehydrogenation feed stream includes unreacted ethane from a steam cracking process, and / or ethane from an external source, such as a natural gas processing plant. Other suitable sources of ethane-containing feed streams are known in the art. In some embodiments, the oxidant stream 101 includes air. The oxidant stream 101 and / or the oxidative dehydrogenation stream 103 can further include trace amounts (e.g., less than 1 wt%) of typical pipeline ethane contaminants such as CH4, propane (C3H8), C4– C10 hydrocarbons, methanol, H2S, and the like. In some embodiments, the oxidative dehydrogenation feed stream 103 further includes CH4. Where water is used as a diluent, typical water feed contaminants, such as acetic acid, ethanol, and heavier oxygenates, can also be present. In some embodiments, the compositions of the oxidant stream 101 and the oxidative dehydrogenation feed stream 103 are selected to provide to the reactor 102, in combination, a mixture including about 10 wt% to about 90 wt% of C2H6. In certain such embodiments, the compositions of the oxidant stream 101 and the oxidative dehydrogenation feed stream 103 are selected to provide to the reactor 102, in combination, a mixture including about 10 wt% to about 90 wt% of O2. In some embodiments, the compositions of the oxidant stream 101 and the oxidative dehydrogenation feed stream 103 are selected to provide to the reactor 102, in combination, a mixture including about 1 wt% to about 40 wt% O2, e.g., about 1 wt% to about 30 wt%, about 1 wt% to about 25 wt%, about 2 wt% to about 20 wt%, or about 5 wt% to about 15 wt% O2. For example, the compositions of the oxidant stream 101 and the oxidative dehydrogenation feed stream 103 can be selected to provide to the reactor 102, in combination, a mixture including about 1 wt% to about 40 wt% of ethane for example, about 1 wt% to about 35 wt%, about 2.5 wt% to about 30 wt%, or about 5 wt% to about 25 wt% of C2H6. In certain such embodiments, the mixture further includes a diluent including H2O, CO2, or both. Non-limiting examples of the oxidative dehydrogenation catalyst include those containing one or more mixed metal oxides. In some embodiments, the catalyst is selected from: catalysts of the formula: MoaVbTecNbdPdeOf where a, b, c, d, e and f are the relative atomic amounts of the elements Mo, V, Te, Nb, Pd and O, respectively; and where a = 1, b = 0.01 to 1.0, c = 0.01 to 1.0, d = 0.01 to 1.0, 0.00 ≤ e ≤ 0.10 and f is a number to at least satisfy the valence state of the metals in the catalyst; catalysts of the formula: NigAhBiDjOfwhere g is a number from 0.1 to 0.9, such as from 0.3 to 0.9, from 0.5 to 0.85, or from 0.6 to 0.8; h is a number from 0.04 to 0.9; i is a number from 0 to 0.5; j is a number from 0 to 0.5; and f is a number to at least satisfy the valence state of the catalyst; A is chosen from Ti, Ta, V, Nb, Hf, W, Y, Zn, Zr, Si and Al or mixtures thereof; B is chosen from La, Ce, Pr, Nd, Sm, Sb, Sn, Bi, Pb, Tl, In, Te, Cr, Mn, Mo, Fe, Co, Cu, Ru, Rh, Pd, Pt, Ag, Cd, Os, Ir, Au, Hg, and mixtures thereof; D is chosen from Ca, K, Mg, Li, Na, Sr, Ba, Cs, and Rb and mixtures thereof; and O is oxygen; catalysts of the formula: MoaEkGlOfwhere E is chosen from Ba, Ca, Cr, Mn, Nb, Ta, Ti, Te, V, W and mixtures thereof; G is chosen from Bi, Ce, Co, Cu, Fe, K, Mg, V, Ni, P, Pb, Sb, Si, Sn, Ti, U, and mixtures thereof; a = 1; k is 0 to 2; l = 0 to 2, with the proviso that the total value of l for Co, Ni, Fe and mixtures thereof is less than 0.5; and f is a number to at least satisfy the valence state of the metals in the catalyst; catalysts of the formula: VmMonNboTepMeqOf where Me is chosen from Ta, Ti, W, Hf, Zr, Sb and mixtures thereof; m is from 0.1 to 3; n is from 0.5 to 1.5; o is from 0.001 to 3; p is from 0.001 to 5; q is from 0 to 2; and f is a number to at least satisfy the valence state of the metals in the catalyst; and catalysts of the formula: MoaVrXsYtZuMvOfwhere X is at least one of Nb and Ta; Y is at least one of Sb and Ni; Z is at least one of Te, Ga, Pd, W, Bi and Al; M is at least one of Fe, Co, Cu, Cr, Ti, Ce, Zr, Mn, Pb, Mg, Sn, Pt, Si, La, K, Ag and In; a=1.0 (normalized); r = 0.05 to 1.0; s = 0.001 to 1.0; t = 0.001 to 1.0; u = 0.001 to 0.5; v = 0.001 to 0.3; and f is a number to at least satisfy the valence state of the metals in the catalyst. a mixed metal oxide having the empirical formula: Mo6.5-7.0V3Odwhere d is a number to at least satisfy the valence of the metals in the catalyst; and a mixed metal oxide having the empirical formula: Mo6.25-7.25V3Od where d is a number to at least satisfy the valence of the metals in the catalyst. In some embodiments, the catalyst is supported on or agglomerated with a binder. Some binders include acidic, basic, or neutral binder slurries of TiO2, ZrO2Al2O3, AlO(OH) and mixtures thereof. Another useful binder includes Nb2O5. The agglomerated catalyst can be extruded in a suitable shape, such as rings, spheres, or saddles, among others, of a size typically used in fixed bed reactors. When the catalyst is extruded, various extrusion aids known in the art can be used. In some cases, the resulting support may have a cumulative surface area of less than 35 m2 / g as measured by BET, in some cases, less than 20 m2 / g, in other cases, less than 3 m2 / g. and a cumulative pore volume from 0.05 to 0.50 cm3 / g. The oxidative dehydrogenation feed stream 103 and oxidant stream 101 can be contacted with the oxidative dehydrogenation catalyst under any condition suitable for the oxidative dehydrogenation reaction. For example, in some embodiments, the feed stream 103, oxidant stream 101, and catalyst are contacted at a temperature of between about 300 ^C and about 500 ^C, or between about 300 ^C and about 450 ^C, or between about 330 ^C and about 425 ^C. In various embodiments, the feed stream 103, oxidant stream 101, and catalyst are contacted at a pressure of between about 10 psia to about 175 psia, or between about 25 psia to about 100 psia. In various embodiments, the residence time of the reactor 102 is between about 0.002 seconds and about 30 seconds, or between about 1 seconds and about 10 seconds. In various embodiments, the gas hourly space velocity (GHSV) of the oxidative dehydrogenation reactor 102 is between about 500 h-1and about 30000 h-1, or greater than about 1000 h-1. Other conditions such as flow rates upstream and downstream of the reactor 102 can be derived from these parameters based on applicable equipment geometries (e.g., reactor volume, catalyst bed size, etc.). Ethane from the feed stream 103 is dehydrogenated to form a dehydrogenated stream 105 including ethylene (C2H4) and H2O. In some embodiments, the dehydrogenated stream 105 includes about 5 wt% to about 75 wt% of ethylene. In some embodiments, the dehydrogenated stream 105 includes about 5 wt% to about 80 wt% of water. In some embodiments, the dehydrogenated stream 105 further includes C2H6, O2, CO2, carbon monoxide (CO), acetic acid, or any combination thereof. For example, in some embodiments, the dehydrogenated stream 105 includes about 0.1 wt% to about 10 wt% of carbon monoxide, about 1 wt% to about 30 wt% ethane, about 0 wt% to about 1 wt% oxygen, and about 0 wt% to about 10 wt% acetic acid. Diluent and other trace contaminants (e.g., described herein) and derivatives thereof can also be present in the dehydrogenated stream 105. The dehydrogenated stream 105 is separated in a separator 104 to form a first separated stream 107 including H2O and a second separated stream 109 including C2H4, CO2, and CO. The first separated stream 107 can include condensable components of the dehydrogenated stream. For example, in some embodiments, the first separated stream 107 further includes acetic acid. In certain such embodiments, the first separated stream 107 includes about 0.0001 wt% to about 30 wt% of acetic acid, or about 10 wt% to about 30 wt% of acetic acid. The second separated stream 109 can include gaseous components of the dehydrogenated stream. For example, in some embodiments, the second separated stream 109 further includes a diluent (e.g., N2, CH4, or both), C2H6 (e.g., unreacted C2H6 from the oxidative dehydrogenation feed stream), O2 (e.g., unreacted O2 from the oxidant stream), or any combination thereof. O2present in the second separated stream 109 can be removed by technologies known in the art, such as adsorption or absorption. In some embodiments, O2present in the second separated stream 109 is removed using a copper- based oxygen scavenging catalyst. In some embodiments, O2 present in the second separated stream 109 is removed by ethanol injection (e.g., to convert O2to CO2and H2O with CO and C2H2, or to covert O2 to acetic acid and C2H4). Separators suitable for gas-liquid separations are known in the art. In some embodiments, the separator 104 includes a condenser (e.g., a shell-and-tube heat exchanger). In certain such embodiments, the dehydrogenated stream 105 includes acetic acid, and separating the dehydrogenated stream 105 includes cooling the dehydrogenated stream 105 to a temperature lower than the dew point of acetic acid. In some embodiments, the separator 104 includes a flash tank. In some embodiments, the separator 104 includes a scrubber, for example, a quench tower, a spray tower, a venture scrubber, or a packed tower. For example, in some embodiments, the dehydrogenated stream 105 includes acetic acid, and separating the dehydrogenated stream 105 includes contacting the dehydrogenated stream 105 with a scrubbing liquid (e.g., including H2O). In certain such embodiments, the first separated stream 107 includes H2O fed to the scrubber (e.g., as scrubbing liquid). The first separated stream 107 can be further separated in a separator (not shown) to form an acetic acid-rich stream including acetic acid and a water-rich stream including H2O. The separation can be by any suitable separation technology, such as distillation or liquid- to-liquid extraction. In certain embodiments, the water-rich stream includes less than about 0.5 wt% of acetic acid. The second separated stream 109 is separated in a separator 106 to form a third separated stream 111 including CO2 and a fourth separated stream 113 including C2H4 and CO. The fourth separated stream 113 can include components of the second separated stream 109 other than CO2. For example, in some embodiments, the fourth separated stream 113 further includes a diluent (e.g., N2, CH4, or both), C2H6(e.g., unreacted C2H6from the oxidative dehydrogenation feed stream 103), or both. In some embodiments, the fourth separated stream 113 includes up to about 80 wt% of C2H4. In some embodiments, the fourth separated stream 113 includes at least about 20 wt% of C2H6. In some embodiments, the fourth separated stream 113 includes up to about 15 wt% of CO. In some embodiments, the fourth separated stream includes up to about 20 wt% of CO2. Separators suitable for CO2 recovery are known in the art. For example, the separator 106 can include a scrubber, for example, a quench tower, a spray tower, a venture scrubber, or a packed tower. In certain such embodiments, separating the second separated stream 109 includes contacting the second separated stream 109 with an amine solvent in an amine tower. In other such embodiments, separating the second separated stream 109 includes contacting the second separated stream 109 with a caustic solvent. The fourth separated stream 113 is separated in a separator 108 to form a fifth separated stream 115 including C2H4and a sixth separated stream 117 including CO. The fifth separated stream 115 can include C2+ hydrocarbons from the fourth separated stream 113. For example, in some embodiments, the fifth separated stream 115 further includes C2H6 (e.g., unreacted C2H6 from the oxidative dehydrogenation feed stream 103). In some embodiments, the fifth separated stream 115 includes up to about 80 wt% C2H4. In some embodiments, the fifth separated stream 115 includes at least about 20 wt% C2H6. In some embodiments, the sixth separated stream 117 further includes a diluent (e.g., N2, CH4, or both). Separators suitable for demethanization are known in the art. For example, the separator 108 can include a cryogenic distillation column. In certain such embodiments, separating the fourth separated stream 113 includes cryogenically distilling the fourth separated stream 113. The fifth separated stream 115 can be further separated in a separator (not shown) to recover C2H4. The separation can be by any suitable technology, such as distillation (e.g., to separate C3+ hydrocarbons) and cryogenic distillation (e.g., to separate C2H4 and C2H6). A water-gas shift feed stream 121 including CO from the sixth separated stream 117 and H2O from a water-rich stream 119 is directed to the water-gas shift reactor 110 including a water-gas shift catalyst (not shown). Suitable configurations of the water-gas shift reactor 110 are known in the art. The water-gas shift reactor 110 can include a fixed- bed reactor, for example, having a pressure drop across the bed of about 15 kPa. In some embodiments, water-rich stream 119 includes H2O from the first separated stream 107. For example, in some embodiments, the first separated stream 107 is further separated, as otherwise described herein, to form an acetic acid-rich stream including acetic acid and the water-rich stream 119 including H2O. The water-gas shift feed stream can further include other components of the sixth separated feed stream 117, such as a diluent. For example, where the oxidant stream 101 includes air, the water-gas shift feed stream 121 can further include N2. In another example, where the oxidative dehydrogenation feed stream 103 includes CH4, the water-gas shift feed stream 121 can further include CH4. In some embodiments, the composition of the water-gas shift feed stream 121 is selected to provide CO and H2O to the reactor 110 in a molar ratio of about 0.1:1 to about 0.9:1, for example, about 0.4:1. Such compositions can be selected, for example, by adjusting the flow of water-rich stream 119. The water-gas shift feed stream 121 can be contacted with the water-gas shift catalyst under and conditions suitable for the water-gas shift reaction. For example, in some embodiments, the water-gas shift feed stream 121 is contacted with the water-gas shift catalyst at a temperature of about 200°C to about 800°C, or about 200°C to about 600°C, such as about 200°C, about 350°C, about 463°C, about 585°C, or about 600°C. CO and H2O from the water-gas shift feed stream 121 react to form a shifted stream 123 including H2 and CO2. The shifted stream 123 can further include components of the water-gas shift feed stream 121, including, for example, N2, CH4, or both. In some embodiments, the shifted stream 123 includes H2O. In certain such embodiments, the H2O can be recovered from the shifted stream 123, for example, by quenching using any suitable technology. In some embodiments, the shifted stream 123 includes up to about 10 mol% of CO, about 10 mol% to about 40 mol% of CO2, about 30 mol% to about 60 mol% of H2O, and about 10 mol% to about 40 mol% of H2. At least a portion of the shifted stream including H2, CO2, or both can be utilized in one or more further processes. In some examples, at least a portion of the shifted stream including CO2 and H2 can be utilized without further separation, for combustion in a furnace or boiler. In certain embodiments, the method includes combusting at least a portion of the shifted stream including CO2 and H2 to produce thermal energy and CO2. In certain such embodiments, the method further includes capturing at least a portion of the CO2. The thermal energy can be used, for example, to heat a steam cracking feed stream including one or more C2–C4hydrocarbons and H2O to form a cracked stream including C2H6. Suitable methods and systems for steam cracking are known in the art. In another example, the thermal energy can be converted to mechanical and, in some examples, electrical energy in an oxy-combustion power plant. Oxy-combustion power plants can be configured and operated as known in the art. For example, in some embodiments, the oxy- combustion power plant includes an oxy-fired broiler, an oxy-fired gasifier, or an oxy-fired gas turbine. At least a portion of the CO2 and H2 from the water-gas shift reaction can be separated to form a hydrogen-rich stream including H2 and a carbon dioxide-rich stream including CO2. Referring to Figure 1, shifted stream 123 is separated in separator 112 to form hydrogen-rich stream 125 including H2 and carbon dioxide-rich stream 127 including CO2. In some embodiments, the hydrogen-rich stream 125 includes at least about 95 wt%, for example, at least about 97 wt%, at least about 98 wt%, or at least about 99 wt% of H2. In some embodiments, the carbon dioxide-rich stream 127 includes at least about 95 wt%, for example, at least about 97 wt%, at least about 98 wt%, or at least about 99 wt% of CO2. In some embodiments, the separator 112 includes a membrane separator. Membrane separators can be configured and operated as known in the art. In some embodiments, the shifted stream 123 is suitable for membrane separation without further pressurization. In other embodiments, separating the shifted stream includes contacting the shifted stream with an amine solvent. In certain such embodiments, CO2can be separated from both the second separated stream and the shifted stream in a single amine tower. At least a portion of the hydrogen-rich stream 125 including H2can be utilized in one or more further processes including hydrogenation. For example, in some embodiments, the method includes contacting a hydrogenation feed stream including an unsaturated hydrocarbon having a first degree of unsaturation and a portion of the hydrogen-rich stream 125 including H2 with a hydrogenation catalyst to form a hydrogenation stream including a saturated hydrocarbon, a second unsaturated hydrocarbon having a second degree of unsaturation less than the first degree of unsaturation, or both. In certain such embodiments, the unsaturated hydrocarbon includes acetylene (C2H2), and the hydrogenated stream includes C2H6, C2H4, or both. In other such embodiments, the unsaturated hydrocarbon includes styrene, and the hydrogenated stream includes ethylbenzene. In some embodiments, the method includes contacting a hydrocracking feed stream including a pyrolysis oil and a portion of the hydrogen-rich stream 125 including H2with a hydrocracking catalyst to form a hydrocracking stream including one or more C2–C4 hydrocarbons. Suitable methods and systems for hydrocracking are known in the art. For example, the hydrocracking feed stream can be contacted with a noble metal hydrocracking catalyst (e.g., zeolite-supported palladium (Pd)) at about 290°C to about 450°C, and about 800 psig to about 30,000 psig. In some embodiments, the hydrocracking reactor includes a fixed-bed or trickle-bed reactor. In some embodiments, the pyrolysis oil includes at least a portion of the product of catalytic pyrolysis of a plastic (e.g., a waste plastic). In certain such embodiments, the plastic includes a polyester such as polyethylene terephthalate (PET) and polycaprolactone, a polyolefin such as low-density polyethylene (LDPE), linear low density polyethylene (LLDPE) medium-density polyethylene (MDPE), high-density polyethylene (HDPE), and polypropylene (PP), a polyvinyl chloride (PVC), a polystyrene (PS), a polycarbonate, a polylactide, a polyether, a polyacrylate, an acrylonitrile rubber such as acrylonitrile butadiene styrene (ABS), styrene acrylonitrile resin (SAN), acrylonitrile styrene acrylate (ASA), and nitrile rubber (NBR), a fiberglass, a nylon, a polyurethane, any copolymer thereof, or any combination thereof. Suitable methods and systems for pyrolysis are known in the art. For example, in some embodiments, the pyrolysis includes thermal pyrolysis without a catalyst. In some embodiments, the pyrolysis includes catalytic pyrolysis. In some embodiments, the pyrolysis includes hydrothermal pyrolysis. In certain such embodiments, plastic (e.g., a waste plastic) and water are mixed in a reactor at high pressure (e.g., about 10 MP) and mild temperature (e.g., about 300°C) to form the pyrolysis oil. In some embodiments, the pyrolysis oil includes a treated pyrolysis oil. In certain such embodiments, the method includes contacting a hydrotreating feed stream including a raw pyrolysis oil and a portion of the hydrogen-rich stream including H2 with a hydrotreating catalyst to form a hydrotreated stream including a treated pyrolysis oil. In certain such embodiments, the hydrocracking feed stream includes at least a portion of the hydrotreated stream including the treated pyrolysis oil. Suitable methods and systems for hydrotreating a pyrolysis oil are known in the art. In some embodiments, a purification feed stream including a raw pyrolysis oil is washed to form the treated pyrolysis oil. Other suitable methods and systems for purifying a pyrolysis oil, e.g. by absorption or adsorption, oxidative desulfurization, oxidative denitrogenation, and oxidative demetellation, are known in the art. In some embodiments, the treated pyrolysis oil has a reduced olefin content as compared to the raw pyrolysis oil. In some embodiments, the treated pyrolysis oil has a reduced content of heteroatom- and / or metal-containing contaminants as compared to the raw pyrolysis oil. In some embodiments, the contaminant includes arsenic, calcium, chromium, iron, lead, aluminum, mercury, oxygen, zinc, potassium, silicon, sodium, copper, nickel, vanadium, sulfur, phosphorus, chlorine, fluorine, or any combination thereof. In some embodiments, the contaminants are present in the treated pyrolysis oil within industrial limits for cracking processes such as hydrocracking, steam cracking, and the like. In some embodiments, the treated pyrolysis oil is diluted with one or more hydrocarbons (e.g., C5 raffinate or butane) to reduce the concentration of contaminants to within industrial limits for cracking processes. In some embodiments, a paraffin content of the pyrolysis oil (e.g., including the treated pyrolysis oil) is about 16 wt% to about 50 wt%, about 16 wt% to about 42 wt%, about 20 wt% to about 40 wt%, or about 20 wt% to about 26 wt%. In some embodiments, a naphthene content of the pyrolysis oil (e.g., including the treated pyrolysis oil) is about 0 wt% to about 40 wt%, about 0 wt% to about 22 wt%, about 2 wt% to about 22 wt%, about 14 wt% to about 22 wt%, or about 2 wt% to about 21 wt%. In some embodiments, an olefin content of the pyrolysis oil (e.g., including the treated pyrolysis oil) is about 0 wt% to about 50 wt%, about 15 wt% to about 50 wt%, about 8 wt% to about 48 wt%, about 8 wt% to about 42 wt%, or about 16 wt% to about 48 wt%. In some embodiments, an aromatics content of the pyrolysis oil (e.g., including the treated pyrolysis oil) is about 0 wt% to about 40 wt%, about 0 wt% to about 20 wt%, about 3 wt% to about 37 wt%, or about 28 wt% to about 39 wt%. In some embodiments, a boiling point range of the pyrolysis oil (e.g., including the treated pyrolysis oil) is about 15°C to about 600°C. In some embodiments, a hydrocarbon range of the pyrolysis oil (e.g., including the treated pyrolysis oil) is C5to C55. In some embodiments, at least a portion of the hydrogen-rich stream 125 including H2can be stored, e.g., as a compressed gas or as a liquid. For example, excess H2can be stored with the H2 demand of a hydrogenation process, hydrocracking process, or hydrotreating process described herein is less than the output of the water-gas shift reaction. In such examples, stored H2can later be used to supplement the feeds to such processes when the hydrogen demand is greater than the output of the water-gas shift reaction. At least a portion of the carbon dioxide-rich stream 127 including CO2can be utilized as a diluent in an oxidative dehydrogenation process, e.g., as otherwise described herein. For example, in some embodiments, the oxidative dehydrogenation feed stream 103 further includes at least a portion of the carbon dioxide-rich stream 127 including CO2. CO2 present in the oxidative dehydrogenation feed stream 103 can be reactive (e.g., as an oxidizing agent), and can change the selectivity of C2H4. The use of CO2 as a reactive diluent in an oxidative dehydrogenation process is described in U.S. Patent No.10,647,625, which is hereby incorporated by reference in its entirety. Figure 2 is a process flow diagram of a method 200 for producing hydrocarbons. The method starts at block 202 with the contacting of an oxidative dehydrogenation (ODH) feed stream including C2H6and an oxidant stream including O2with an oxidative dehydrogenation catalyst to form a dehydrogenated stream including C2H4, CO2, CO, and H2O. At block 204, a water-gas shift feed stream including H2O and at least a portion of the dehydrogenated stream including CO with a water-gas shift (WGS) catalyst to form a shifted stream including H2 and CO2. Definitions The terms “a”, “an”, and “the” are used herein to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” has the same meaning as “A, B, or A and B”. In addition, it is to be understood that the phraseology or terminology employed in this disclosure, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section. Values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (for example, 1%, 2%, 3%, and 4%) and the sub-ranges (for example, 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y”, unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z”, unless indicated otherwise. As used herein, the term “about” can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range. In the methods described herein, the acts can be carried out in any order, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process. EXAMPLES The invention is further described in the following examples, which do not limit the scope of the invention described in the claims. Example 1. Modeling of Water-Gas Shift Reaction The water-gas shift reaction (WGSR) of CO and steam (H2O) was simulated using ASPEN HYSYS v11.0. The Peng-Robinson method was used as a general equation of state. The reaction was modeled using the Equilibrium Reactor model. The equilibrium constant was assumed to be a function of temperature expressed using the equation: The inlet feed and 24.7 bar. The feed composition was 100 kmol / hr of CO and 250 kmol / hr of H2O. Figure 3 shows a flowsheet of the simulation including the WGSR, quenching, and knockout of the H2O. Three conditions were simulated using the model: low-temperature reaction, high-temperature reaction, and adiabatic conditions. The low-temperature reaction condition WGSR was simulated at 350°C. Table 1 shows the material and energy balance for the reaction. The overall conversion of CO was 97% given equimolar composition of CO2 and H2. Table 1. Material and Energy Balances for Reaction at Low Temperature Input WGS TP WGS COOL GAS LIQ BTM PG Vapour Fraction 1.0000 1.0000 0.0000 0.4514 1.0000 0.0000 Temperature (K) 623.1 623.3 623.3 229.7 229.6 229.7 Pressure (bar) 24.65 24.50 24.50 24.35 24.20 24.35 Molar Flow (kgmole / h) 350.0 350.0 0.0000 350.0 158.0 192.0 Mass Flow (kg / s) 2.029 2.029 0.0000 2.029 0.7876 1.241 Liquid Vol. Flow (m3 / h) 8.017 10.84 0.0000 10.84 5.998 4.839 Heat Flow (MW) -18.86 -19.89 0.0000 -23.39 -6.554 -16.83 Mol Frac. CO 0.2857 0.0087 0.0086 0.0087 0.0191 0.0001 Mol Frac. CO20.0000 0.2771 0.2766 0.2771 0.3676 0.2026 Mol Frac. H2O 0.7143 0.4372 0.4393 0.4372 0.0000 0.7970 Mol Frac. H20.0000 0.2771 0.2755 0.2771 0.6133 0.0004 The high-temperature reaction condition WGSR was simulated at 463°C. Table 2 shows the material and energy balance for the reaction. The overall conversion of CO was 92% given equimolar composition of CO2and H2. Table 2. Material and Energy Balances for Reaction at High Temperature Input WGS TP WGS COOL GAS LIQ BTM PG Vapour Fraction 1.0000 1.0000 0.0000 0.5464 1.0000 0.0000 Temperature (K) 623.1 736.1 736.1 293.9 293.8 293.9 Pressure (bar) 24.65 24.50 24.50 24.35 24.20 24.35 Molar Flow (kgmole / h) 350.0 350.0 0.0000 350.0 191.2 158.8 Mass Flow (kg / s) 2.029 2.029 0.0000 2.029 1.228 0.8010 Liquid Vol. Flow (m3 / h) 8.017 10.69 0.0000 10.69 7.792 2.898 Heat Flow (MW) -18.86 -19.41 0.0000 -22.91 -10.24 -12.66 Mol Frac. CO 0.2857 0.0232 0.0231 0.0232 0.0425 0.0000 Mol Frac. CO20.0000 0.2625 0.2620 0.2625 0.4758 0.0057 Mol Frac. H2O 0.7143 0.4518 0.4540 0.4518 0.0013 0.9943 Mol Frac. H20.0000 0.2625 0.2609 0.2625 0.4805 0.0000 The adiabatic reaction condition WGSR was simulated (ΔQr = 0). A temperature rise of 858.4K (585°C) was observed. Table 3 shows the material and energy balance for the reaction. The overall conversion of CO was 84% given equimolar composition of CO2 and H2. Table 3. Material and Energy Balances for Adiabatic Reaction Input WGS TP WGS COOL GAS LIQ BTM PG Vapour Fraction 1.0000 1.0000 0.0000 0.5559 1.0000 0.0000 Temperature (K) 623.1 858.4 858.4 376.1 376.0 376.1 Pressure (bar) 24.65 24.50 24.50 24.35 24.20 24.35 Molar Flow (kgmole / h) 350.0 350.0 0.0000 350.0 194.6 155.4 Mass Flow (kg / s) 2.029 2.029 0.0000 2.029 1.250 0.7796 Liquid Vol. Flow (m3 / h) 8.017 10.47 0.0000 10.47 7.660 2.815 Heat Flow (MW) -18.86 -18.86 0.0000 -22.36 -10.26 -12.10 Mol Frac. CO 0.2857 0.0443 0.0443 0.0443 0.0797 0.0000 Mol Frac. CO20.0000 0.2414 0.2414 0.2414 0.4329 0.0017 Mol Frac. H2O 0.7143 0.4729 0.4729 0.4729 0.0532 0.9982 Mol Frac. H20.0000 0.2414 0.2414 0.2414 0.4342 0.0001 The results, shown in Tables 1–3, indicate that a CO-containing stream from oxidative dehydrogenation can be reacted with water in a water-gas shift reaction to produce CO2and H2. Example 2. Oxidative Dehydrogenation of CO2-Containing Feed A fixed-bed reactor unit (FBRU) was used to demonstrate the effect of feed composition and / or reaction operating conditions on oxidative dehydrogenation (ODH) product distribution. The apparatus is shown in Figure 4, and includes two fixed-bed tubular reactors in series. Each reactor was wrapped in an electrical heating jacket and sealed with ceramic insulating material. Each reactor was a SS316L tube having a 1-inch outer diameter and 34-inch length. In the experiments, ethane, ethylene, carbon dioxide, oxygen, and steam were fed separately and premixed prior to reactor inlet with the compositions indicated below, and both reactors were controlled at the same reaction temperature. The temperature of each of the reactors was monitored using a corresponding 7-point thermocouple. The catalyst bed included one weight unit of catalyst to 2.33 units of weight of stainless steel powder; the total weight of catalyst in each reactor was 150 g. The rest of the reactor below and above the catalyst bed, was packed with quartz powder and secured in place with glass wool on the top and bottom of the reactor tub to avoid any bed movement during the experimental runs. Constant experimental conditions included WHSV 0.55–0.76 h-1(GHSV = 610 h-1), reaction temperature of 334–338°C, reaction pressure at ambient, and dry feed gas composition of C2H6 / C2H4 / O2 / CO2 of 33 / 0 / 14 / 54. Varied experimental conditions included the quantity of water in the ODH feed, which was changed within the range of 0–1 cm3for experiments 1-1 to 1-5. At each water flow rate, the reactors were operated for 1–3 days. The reactors were operated without interruption as the water flow rate was being changed. Immediately following experiment 1-5, the operating conditions of the reactors were changed for about 1 day to match the operating conditions in experiment 1-1. Immediately following experiment 1-6, the operating conditions of the reactors were changed for about 1 day to match the operating conditions in experiment 1-5. Results are shown in Table 4, below. Table 4. ODH Product Distribution at Different Flow Rates of Feed Water Experiment Flow Rate Ethane Normalized Selectivity (wt%)2(cm3 / min) Conversion Ethylene CO2CO Acetic Acid (%) 1-1 0.0 38.41 82.98 6.30 8.13 2.60 1-2 0.1 41.58 82.01 6.03 7.66 4.30 1-3 0.4 43.51 79.20 6.04 7.04 7.73 1-4 0.8 45.82 79.19 3.61 6.82 10.39 1-5 1.0 49.84 88.71 -9.83 7.27 13.84 1-6 0.01 37.88 84.19 4.39 7.76 3.66 1-7 1.0 49.97 90.37 -10.52 7.34 12.801all reported data are the average of two or more experimental data2selectivity is calculated using the following equation: ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^ ^^ ^^ / ^^ ^^ ^^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^^^^ ^^. %^ൌ^ ^^ ^^ / ^^ ^^ ^^ ^^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ଶ^^^൦^ ^^ ^^^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ ^^ଶ ^^^^^ / ^^ ^^ ^^^ ^^ ^^ ^^. ^^ ^^ ^^ ^^ ^^. ^^ ^^ ^^^^ ^^ ^^ℎ ^^ ^^ ^^ ^^ଶ ^^^൪ ∗ ^^ ^^ ^^ ^^ଶ^^^^ ^^ ^^ଶ ^^^ / ^^ ^^ ^^ ^^ଶ ^^^^where X is the product that is being assessed, the net mass flow rate refers to flow in g / min for X or ethane entering the reactor minus the flow rate exiting the reactor, and molar equivalent (Mol. equiv.) refers to the amount of X, in moles, that reacts completely with one mole of C2H6. Selectivity is referred to as a wt% despite the fact the calculation results in conversion of wt% to a molar percentage, because weight flow rate is the measurement that is used in the calculation. As shown in Table 4, the increase in flow rate of feed water from 0–1 cm3 / min (experiment 1-1 to 1-5) led to a decrease in the selectivity towards CO2and eventually negative selectivity towards CO2 at a water flow rate of 1 cm3 / min. This indicated that at 1 cm3 / min flow rate, the CO2was consumed and was likely incorporated to formation of ethylene and other ODH byproducts. The results of experiment 1-6 indicated the repeatability of the results of experiment 1-1, and the results of experiment 1-7 indicated the repeatability of the results of experiment 1-5. Other implementations are also within the scope of the following claims.

Claims

CLAIMS 1. A method of producing hydrocarbons, the method comprising: contacting an oxidative dehydrogenation feed stream comprising C2H6 and an oxidant stream comprising O2with an oxidative dehydrogenation catalyst to form a dehydrogenated stream comprising C2H4, CO2, CO, and H2O; and contacting a water-gas shift feed stream comprising H2O and at least a portion of the dehydrogenated stream comprising CO with a water-gas shift catalyst to form a shifted stream comprising H2and CO2.

2. The method of claim 1, wherein the dehydrogenated stream further comprises C2H6, O2, or both.

3. The method of claim 1 or claim 2, wherein the oxidative dehydrogenation feed stream further comprises a diluent, and the dehydrogenated stream further comprises the diluent.

4. The method of claim 3, wherein the diluent comprises H2O, CH4, CO2, Ar, He, N2, or any combination thereof.

5. The method of claim 3, wherein the diluent comprises CH4, N2, or both.

6. The method of any of claims 1–5, further comprising separating the dehydrogenated stream to form a first separated stream comprising H2O and a second separated stream comprising C2H4, CO2, and CO, wherein the water-gas shift feed stream comprises at least a portion of the second separated stream comprising CO.

7. The method of claim 6, wherein the second separated stream further comprises C2H6, O2, a diluent, or any combination thereof.

8. The method of claim 6 or claim 7, wherein: the dehydrogenated stream further comprises acetic acid; separating the dehydrogenated stream comprises contacting the dehydrogenated stream with a scrubbing liquid; and the first separated stream further comprises acetic acid and the scrubbing liquid.

9. The method of claim 6 or claim 7, wherein: the dehydrogenated stream further comprises acetic acid; separating the dehydrogenated stream comprises cooling the dehydrogenated stream to a temperature lower than a dew point of acetic acid; and the first separated stream further comprises acetic acid.

10. The method of any of claims 6–9, wherein the water-gas shift feed stream comprises at least a portion of the first separated stream comprising H2O.

11. The method of claim 10, wherein: the first separated stream further comprises acetic acid; the method further comprises separating the first separated stream to form an acetic acid-rich stream comprising acetic acid and a water-rich stream comprising H2O; and the first separated stream comprises at least a portion of the water-rich stream comprising H2O.

12. The method of any of claims 6–11, further comprising separating the second separated stream to form a third separated stream comprising CO2and a fourth separated stream comprising C2H4 and CO, wherein the water-gas shift feed stream comprises at least a portion of the fourth separated stream comprising CO.

13. The method of claim 12, wherein the fourth separated stream further comprises C2H6, a diluent, or any combination thereof.

14. The method of claim 12 or claim 13, wherein separating the second separated stream comprises contacting the second separated stream with an amine solvent.

15. The method of any of claims 12–14, further comprising separating the fourth separated stream to form a fifth separated stream comprising C2H4 and a sixth separated stream comprising CO, wherein the water-gas shift feed stream comprises at least a portion of the sixth separated stream comprising CO.

16. The method of claim 15, wherein the fifth separated stream further comprises C2H6.

17. The method of claim 15 or claim 16, wherein the sixth separated stream further comprises a diluent.

18. The method of any of claims 15–17, wherein separating the fourth separated stream comprises cryogenically distilling the fourth separated stream.

19. The method of any of claims 3–18, wherein the oxidant stream comprises air, and the water-gas shift feed stream further comprises N2.

20. The method of any of claims 3–19, wherein the water-gas shift feed stream further comprises CH4.

21. The method of any of claims 1–20, further comprising combusting at least a portion of the shifted stream comprising H2and CO2to produce thermal energy and CO2; and capturing at least a portion of the CO2.

22. The method of claim 21, further comprising using at least a portion of the thermal energy to heat a steam cracking feed stream comprising one or more C2–C4hydrocarbons and H2O to form a cracked stream comprising C2H6.

23. The method of any of claims 1–20, further comprising separating the shifted stream to form a hydrogen-rich stream comprising H2and a carbon dioxide-rich stream comprising CO2.

24. The method of claim 23, wherein separating the shifted stream comprises contacting the shifted stream with a membrane.

25. The method of claim 23, wherein separating the shifted stream comprises contacting the shifted stream with an amine solvent.

26. The method of any of claims 23–25, further comprising contacting a hydrocracking feed stream comprising a pyrolysis oil and a portion of the hydrogen-rich stream comprising H2with a hydrocracking catalyst to form a hydrocracked stream comprising one or more C2–C4 hydrocarbons.

27. The method of claim 26, further comprising contacting a hydrotreating feed stream comprising a raw pyrolysis oil and a portion of the hydrogen-rich stream comprising H2 with a hydrotreating catalyst to form a hydrotreated stream comprising a treated pyrolysis oil, wherein the hydrocracking feed stream comprises at least a portion of the hydrotreated stream comprising the treated pyrolysis oil.

28. The method of any of claims 23–27, further comprising contacting a hydrogenation feed stream comprising an unsaturated hydrocarbon having a first degree of unsaturation and a portion of the hydrogen-rich stream comprising H2with a hydrogenation catalyst to form a hydrogenated stream comprising a saturated hydrocarbon, a second unsaturated hydrocarbon having a second degree of unsaturation, or both, wherein the second degree of unsaturation is less than the first degree of unsaturation.

29. The method of claim 28, wherein the unsaturated hydrocarbon comprises C2H2, and the hydrogenated stream comprises C2H6, C2H4, or both.

30. The method of claim 28, wherein the unsaturated hydrocarbon comprises styrene, and the hydrogenated stream comprises ethylbenzene.

31. The method of any of claims 23–30, further comprising storing at least a portion of the hydrogen-rich stream comprising H2.

32. The method of any of claims 23–31, wherein the oxidative dehydrogenation feed stream further comprises at least a portion of the carbon dioxide-rich stream comprising CO2.

33. A system for producing hydrocarbons, the system comprising: an oxidative dehydrogenation reactor configured to contact an oxidative dehydrogenation feed stream comprising C2H6 and an oxidant stream comprising O2 with anoxidative dehydrogenation catalyst to form a dehydrogenated stream comprising C2H4, CO2, CO, and H2O; and a water-gas shift reactor configured to contact a water-gas shift feed stream comprising H2O and at least a portion of the dehydrogenated stream comprising CO with a water-gas shift catalyst to form a shifted stream comprising H2 and CO2.

34. The system of claim 33, further comprising a separator configured to separate the shifted stream to form a hydrogen-rich stream comprising H2 and a carbon dioxide-rich stream comprising CO2.

35. The system of claim 34, wherein the separator comprises a membrane separator configured to contact the shifted stream with a membrane.

36. The system of claim 34, wherein the separator comprises an amine tower configured to contact the shifted stream with an amine solvent.

37. The system of claim 36, wherein the amine tower is further configured to separate CO2from the dehydrogenated stream.

38. The system of any of claims 34–37, further comprising a hydrocracking reactor configured to contact a hydrocracking feed stream comprising a pyrolysis oil and a portion of the hydrogen-rich stream comprising H2 with a hydrocracking catalyst to form a hydrocracked stream comprising one or more C2–C4 hydrocarbons.

39. The system of claim 38, further comprising a hydrotreating reactor configured to contact a hydrotreating feed stream comprising a raw pyrolysis oil and a portion of the hydrogen-rich stream comprising H2with a hydrotreating catalyst to form a hydrotreated stream comprising a treated pyrolysis oil, wherein the hydrocracking feed stream comprises at least a portion of the hydrotreated stream comprising the treated pyrolysis oil.

40. The system of any of claims 34–39, further comprising a hydrogenation reactor configured to contact a hydrogenation feed stream comprising an unsaturated hydrocarbon having a first degree of unsaturation and a portion of the hydrogen-rich stream comprising H2with a hydrogenation catalyst to form a hydrogenated stream comprising a saturated hydrocarbon, a second unsaturated hydrocarbon having a second degree of unsaturation, or both, wherein the second degree of unsaturation is less than the first degree of unsaturation.

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