Methods and design for production of cracked- naphtha range hydrocarbon from waste carbon materials

Abstract

It is provided a system and process for producing a recycled cracked naphtha product slate comprising gasifying in a gasifier waste material to obtain a crude syngas, the waste material comprising carbon and hydrogen in a molar ratio H:C; cleaning the crude syngas in a cleaning unit to obtain a clean syngas comprising H2 and CO in a molar ratio H2:CO of between 0.5:1 and 5:1; and reacting the clean syngas in a reactor in the presence of a catalyst comprising a mixture of transition metal oxides to obtain the recycled cracked naphtha product slate, wherein the molar ratio H:C is less than 2.5.

Description

CROSS-REFERENCE TO RELATED APPLICATION

[0001] The present application is claiming priority from U.S. Provisional Application No. 63 / 434,891 filed Dec. 22, 2022, the content of which is hereby incorporated by reference in its entirety.TECHNICAL FIELD

[0002] The disclosure relates to the field of producing recycled cracked naphtha product slate from a waste material.BACKGROUND OF THE ART

[0003] There are two well established processes for converting syngas to cracked naphtha products, which is a hydrocarbon pool which can range from C2 to C10 including aromatics. Olefins rich naphtha is used for blending gasoline as it enables economic production of high-octane transportation fuels. The first process is the Fischer-Tropsch synthesis (FTS) that converts syngas to primarily diesel grade fuel. FTS typically utilizes syngas having a H2 / CO ratio greater than 2:1. The second process is the methanol to gasoline (MT) process for producing gasoline from syngas via a methanol intermediate. Production of methanol also requires a syngas having a H2 / CO ratio greater than 2. However, more sustainable processes and green technologies are desired to produce cracked naphtha.

[0004] U.S. Pat. No. 7,214,720 describes a process involving the steps of gasification followed by Fischer-Tropsch (FT) conversion and subsequent separation and recycling of at least a portion of the naphtha to the gasifier. However, the need to recycle part of the naphtha to the gasifier reduces the efficiency of this process as a source of bio-renewable naphtha and subsequently steam-cracked naphtha product slate.

[0005] A variety of patents and applications (U.S. Pat. No. 5,494,653, WO 2001 / 060773, WO 2001 / 064610, and WO 2002 / 055633) describe the use of synthesis gas for producing hydrocarbon by a FTS, often combined with hydrofracking. The FTS produces hydrocarbons in diesel or kerosene fractions and other heavy hydrocarbons that require further cracking in the presence of catalysts at a temperature of between 530° C. and 980° C., in order to obtain steam-cracked naphtha range hydrocarbon. However, these processes generate significant volumes of H2, CO and CO2 that are wasted and offer limited economic advantage. Therefore, the sustainability of such processes is limited.

[0006] U.S. application No. 2019 / 0225489 provides an approach where syngas in the presence of different catalysts is converted to a product slate similar to cracked-naphtha products. U.S. Pat. No. 9,919,981 also describes a product slate similar to cracked naphtha using a hybrid catalyst. Moreover, U.S. application No. 2020 / 0231525 describes a product slate of C2+ that may include oxygenates including methanol and DME. However, none of these proposed processes achieve adequate sustainability.

[0007] Therefore, improvements are desired in the production of cracked naphtha products, particularly with respect to the efficiency and sustainability of such processes.SUMMARY

[0008] In one aspect there is provided a system for producing a recycled cracked naphtha product slate, the system comprising:

[0009] a gasifier to gasify a waste material comprising carbon and hydrogen in a molar ratio H:C, to produce a crude syngas;

[0010] a cleaning unit to clean the crude syngas and produce a clean syngas comprising H2 and CO in a molar ratio H2:CO of between 0.5:1 to 5:1; and

[0011] a reactor comprising a catalyst to produce the recycled cracked naphtha product slate from the clean syngas, the catalyst comprising a mixture of transition metal oxides,wherein the molar ratio H:C in the gasifier is less than 2.5.

[0012] In one embodiment the waste material is selected from at least one of the group consisting of municipal solid waste (MSW), commercial solid waste, institutional solid waste, plastic waste, homogenous solid biomass, non-homogeneous solid biomass, and combinations thereof.

[0013] In one embodiment the waste material is diapers.

[0014] In one embodiment the waste material is single use waste plastics.

[0015] In one embodiment the gasifier comprises a fluidized bed, a fixed bed, or a slurry phase.

[0016] In one embodiment the gasifier comprises a reforming section.

[0017] In one embodiment the system further comprises a storage unit for storing the waste material.

[0018] In one embodiment the cleaning unit comprises a scrubbing column.

[0019] In one embodiment the cleaning unit comprises an adsorption column.

[0020] In one embodiment the system further comprises a recycling stream from the reactor to the gasifier.

[0021] In one embodiment the system further comprises a separation unit to separate different hydrocarbon components of the recycled cracked naphtha product slate.

[0022] In one embodiment the recycled cracked naphtha product slate comprises at least 90% by weight of C2-C10 hydrocarbons on a CO2 free basis.

[0023] In a further aspect, there is provided a method of producing a recycled cracked naphtha product slate, the method comprising:

[0024] gasifying a waste material to obtain a crude syngas, the waste material comprising carbon and hydrogen in a molar ratio H:C;

[0025] cleaning the crude syngas to obtain a clean syngas comprising H2 and CO in a molar ratio H2:CO of between 0:5:1 and 5:1; and

[0026] reacting the clean syngas in the presence of a catalyst comprising a mixture of transition metal oxides to obtain the recycled cracked naphtha product slate,wherein the molar ratio H:C is less than 2.5.

[0027] In one embodiment the method further comprises, reforming the crude synthesis gas and / or the clean synthesis gas to adjust the H2:CO ratio.

[0028] In one embodiment cleaning comprises quenching, scrubbing, and adsorbing the crude syngas.

[0029] In one embodiment the step of cleaning comprises removing at least one of ammonia (NH3), sulfur, chlorine, volatile metals, aromatic tars, tars, fine ashes, and char.

[0030] In one embodiment the method further comprises recycling at least a portion of the waste material generated by the reactor to the gasifier.

[0031] In one embodiment the recycled cracked naphtha product slate comprises less than 10% of methane.

[0032] In one embodiment the step of reacting the clean syngas is performed at a temperature of between 160° C. and 400° C.

[0033] In one embodiment the step of reacting the clean syngas is performed at a pressure of between 1 and 100 barg.

[0034] In one embodiment the method further comprises separating the recycled cracked

[0035] naphtha product slate into different hydrocarbon compositions.

[0036] In one embodiment the method further comprises separating higher carbon molecules

[0037] from the recycled cracked naphtha product slate and feeding said higher carbon molecules into a naphtha cracker producing lower olefins.

[0038] In one embodiment the method further comprises separating the lighter carbon

[0039] molecules from the recycled cracked naphtha product slate and mixing said lighter carbon molecules with lower olefins recovered from the naphtha cracker.

[0040] In an embodiment, the catalyst comprises in weight percent 53.16 O, 6.01 Al, 33.22 Si, 2.98 Fe, 0.75 Na and 6.42 K. In a further embodiment, the catalyst comprises in weight percent 55.5 O, 7.2 Al, 33.2 Si, 3 Fe, 1 Zn, and 0.1 K.

[0041] Many further features and combinations thereof concerning the present improvements will appear to those skilled in the art following a reading of the instant disclosure.DESCRIPTION OF THE DRAWINGS

[0042] FIG. 1 is a schematic diagram of a system for producing a recycled cracked naphtha product slate according to the present disclosure.

[0043] FIG. 2 is a flow chart of a method for producing a recycled cracked naphtha product slate according to the present disclosure.DETAILED DESCRIPTION

[0044] It is provided a system and process for producing a recycled cracked naphtha product slate from a waste material.

[0045] As encompassed herein, a waste material is a carbonaceous material (gas, liquid or solid) that contains the “carbon” atom. In most cases, these atoms may be originated from plants or animals and their derivatives, or from fossil fuel and its derivatives. Examples of waste materials include, but are not limited to, Municipal Solid Waste (MSW); Industrial, Commercial, and Institutional waste (IC&I); Construction and Demolition waste (C&D); any petroleum product; plastic; homogenous and / or non-homogeneous biomass (such as forestry or agricultural waste).

[0046] Making reference to FIG. 1, there is provided a system 100 comprising a gasifier 102, a cleaning unit 104 and a reactor 106, for producing a recycled cracked naphtha product slate from waste materials. The term “recycled cracked naphtha product slate” as used herein refers to hydrocarbons recycled from waste materials that mimic cracked naphtha hydrocarbons product in their distribution of hydrocarbon concentrations that is obtained from a waste feedstock, consisting thus into a hydrocarbon product with a composition range similar to a reactor output product in a Naphta Cracker. In one embodiment, the range of hydrocarbons of the recycled cracked naphtha product slate is C2-C10. For example, the recycled cracked naphtha product slate can comprise in weight percent, at least 90%, 93%, 95%, 96%, 97%, or 98% of C2-C10. In certain embodiments, a specific range of naphtha hydrocarbons can be produced. For example, in some embodiments, at least 80% by weight of the recycled cracked naphtha product slate is C3-C10, C3-C5, C3-C4, or C5-C10. The recycled cracked naphtha product slate has olefins, paraffins, and aromatics, however olefins have the most value and a larger olefin percentage is preferred in some embodiments. For example, the recycled cracked naphtha product slate can comprise at least 75% by weight of olefins.

[0047] Naphtha obtained during the atmospheric distillation of crude oil has the following composition: C3-C4 (8%), C5 (22%), C6 (20%), C7 (18%), C8 (12%), C9 (11%), C10-C15 (9%). Distilled naphtha is a C3-C10 hydrocarbon cut that is commonly used as a feedstock for both catalytic reformers and steam crackers. Steam-recycled cracked naphtha product slate which is produced by steam cracking of naphtha at high temperature produces on average ethylene (30%), H2 and CH4 (25%), propylene (13%), butadiene (2%), mixed butene (8%), C5+ hydrocarbon (8%) and aromatics (11%), a product slate that provides a C2-C10 hydrocarbon. The recycled cracked naphtha product slate according to the present disclosure mimics cracked naphtha, and preferably has an increased specificity for hydrocarbons other than methane. In one embodiment, the recycled cracked naphtha product slate of the present disclosure comprises less than 10% methane, less than 5% methane, or less than 3% methane. In one embodiment, the recycled cracked naphtha product slate comprises less than 0.3% by weight of olefins. In a further embodiment, the recycled cracked naphtha product slate comprises less than 7.0% by weight of naphthene (such as cyclohexane, cyclopentane and the like). In yet a further embodiment, the recycled cracked naphtha product slate comprises less than 2.0% by weight of aromatics. In still a further embodiment, the recycled cracked naphtha product slate is free of benzene and oxygenates. In one example, the recycled cracked naphtha product slate is a C5-C10. In a further example, the recycled cracked naphtha product slate consists of hydrocarbons having a boiling point 21° C. to 204° C. The recycled cracked naphtha product slate can comprise C5, C6, C7, C8, C9, and C10 paraffins (straight and branched chains). Other examples of the recycled cracked naphtha product slate includes by weight ethylene 24%, propylene 20%, butadiene 3 to 5%, BTX (benzene toluene xylene) 1-2%, and petroleum ethers (C5 to C6) 25%.

[0048] Also making reference to FIG. 2, there is provided a method 200 of producing the recycled cracked naphtha product slate comprising gasifying 202 a waste material to produce a crude syngas, cleaning 204 the crude syngas to obtain a clean syngas, optionally optimizing 206 the syngas, and reacting 208 the clean syngas with a catalyst to yield the recycled cracked naphtha product slate. An exemplary catalyst comprises 52-57 0, 5.5-7.5 Al, 31-35 Si, and 2.5-3.5 Fe in weight percent. The waste material is a carbonaceous material that is generated as a waste. Processes developed to convert high ratio (H2 / CO>2) syngas from natural gas are typically inefficient when applied to converting syngas derived from biomass and other wastes. Specifically, the oxygen present in the biomass is rejected with hydrogen and in order to increase the H:C ratio from that of the feed to that of the product, carbon is rejected as CO2. Therefore, the conversion of waste natural gas (H:C of about 4) will ultimately result in less CO2 production than biomass (H:C<1 after oxygen rejection) and plastic wastes (H:C of about 2). Accordingly, to improve the sustainability of the present systems and methods, the ratio of syngas produced from biomass can be shifted to a higher H2 / CO2 ratio via the water-gas shift reaction. This could result in higher H2 / CO ratio syngas. However, it can be thermally inefficient because the reaction itself is exothermic and because of the requirement to produce steam, which results in lower thermal efficiency and lower carbon yield to product. In addition, the nature of the carbon source selected as raw material for synthesis gas production also affects the carbon efficiency (and CO2 footprint). Specifically, syngas produced from biomass has a significantly lower H2 / CO ratio than syngas produced from natural gas because biomass has a lower heating value and is deficient in hydrogen relative to that of natural gas. However, as disclosed herein, it is provided a process where surprisingly the recycled cracked naphtha product slate can be obtained from a waste material (H:C<2.5) with improved efficiency and sustainability.

[0049] As evident from the above, the waste material comprises carbon and hydrogen. More specifically, the waste material has a molar ratio H:C<2.5. In some embodiment, the molar ratio H:C is less than 2.4, less than 2.3, or less than 2.2. The waste material is a renewable source and is thus substantially free of natural gas and oil (crude or treated). The term “substantially free of” can be defined as having no deliberate additions of such components. The term “substantially free of” can also be defined as having less than 10%, less than 7%, less than 5%, or less than 3% by weight of a certain chemical species. In some embodiments, the waste material comprises at least 50% by weight of carbon. Examples of waste materials include but are not limited to biomass, municipal solid waste (MSW), waste plastics and combinations thereof. In some embodiments, the waste materials are in a solid state at room temperature. MSW can contain a mixture of biomass waste and hydrocarbon wastes such as plastics. Homogeneous biomass-rich materials are biomass-rich materials which come from a single source. Such materials include, but are not limited to, materials from coniferous trees or deciduous trees of a single species, agricultural materials from a plant of a single species, such as hay, corn, or wheat, or for example, primary sludge from wood pulp, and wood chips. It may also be materials from refined single source like waste cooking oil, lychee fruit bark or stillage from corn to methanol by-product. Non-homogeneous biomass-rich materials in general are materials which are obtained from plants of more than one species. Such materials include, but are not limited to, forest residues from mixed species, and tree residues from mixed species obtained from debarking operations or sawmill operations. The waste plastics used in the present disclosure can be recyclable plastics and / or non-recyclable plastics. In one embodiment, the waste material is a carbonaceous waste material whereas a carbonaceous material refers to a solid that contains “carbon” atoms. For example, used diapers are being landfilled and the method of the present disclosure allows the use of such otherwise wasted material as feedstock for the recycled cracked naphtha product slate synthesis; and results in a circular diaper usage similar to circular plastic recycling. In another example, the waste material is a waste plastic contaminated with biomass, such as single use waste plastics of the food industry (delivery, take out, packaging etc.). Such materials can comprise at least 70% by weight of plastics and at most 30% by weight of biomass. The waste materials can be stored in a waste storage unit near or part of the system 100 or can be transported to the system 100 and used immediately. For example, a truck transporting MSW can unload the MSW in a waste storage unit and / or directly into the feed of the gasifier 102.

[0050] The waste materials are converted to syngas by gasification 202 in the gasifier 102. In one example, the gasification of biomass converts the biomass into predominantly carbon monoxide and hydrogen (syngas) by reacting at high temperatures, with a controlled amount of oxygen and / or steam. Synthesis gas, also called syngas, is a fuel gas mixture comprising primarily of carbon monoxide (CO), optionally carbon dioxide (CO2) and hydrogen (H2). Syngas can be produced from many sources, including biomass (e.g. compostable waste), or virtually any carbonaceous material, by reaction with steam (steam reforming), carbon dioxide (dry reforming), air (partial oxidation), oxygen (partial oxidation) or any mixture of the reactants listed.

[0051] Syngas is an important feedstock in the chemical industry. It is a gas mixture comprising primarily of hydrogen (H2) and carbon monoxide (CO) and may further contain other gas components such as carbon dioxide (CO2), water (H2O), methane (CH4) and / or nitrogen (N2). Syngas is a key platform for the utilization of non-petroleum carbon resources. Syngas can also be produced from renewable carbon feedstocks (i.e. the waste materials) such as biomass, municipal solid waste and non-recyclable plastic waste.

[0052] The gasification according to the present disclosure can maximize the conversion of the carbon present in the waste material into a product slate that mimic cracked naphtha (i.e. the recycled cracked naphtha product slate). The feedstock for the gasifier comprises the waste materials of which a significant portion of the carbon may be biogenic in nature if the waste material chosen to be gasified is biomass or bio-based waste such as municipal solid waste or commercial and institutional waste. On the other hand, if the waste material to be gasified is a plastic waste (for an advance recycling approach) the maximum utilization of such carbon present in the syngas through downstream technical route can be optimized. One optimization can be by manufacturing higher carbon molecules to further increase the recyclable carbon as a naphtha feedstock that could be co-fed directly into a naphtha cracker. Alternatively, the process described herein could be optimized to produce lighter hydrocarbons that blend directly with the typical output of a naphtha cracker and thus leverage the separation and purification equipment already installed with the typical naphtha cracker.

[0053] Thus, it is provided that higher carbon molecules are separated from the recycled cracked naphtha product slate produced herein and feed into a naphtha cracker producing lower olefins. Lower olefins are olefins having 2 to 4 carbon atoms, which are known to be suitable starting materials for known chemical processes. The production of lower olefins from cracked hydrocarbon feeds is well-known and has been applied industrially in many petrochemical production facilities.

[0054] It is also encompassed that lighter carbon molecules from the recycled cracked naphtha product slate as produced herein can be feed and mixed with the lower olefins recovered from the naphta cracker in for example petrochemical production facilities.

[0055] Following the gasification 202, the crude syngas is cleaned 204 using a cleaning unit 104. The cleaning unit 104 comprises one or more cleaning columns for example a separation column, an adsorption column and / or a scrubbing column. The cleaning step 204, can also comprise a quenching step to reduce the temperature of the influent crude syngas. The quenching can be performed by any suitable method known in the art. The crude syngas can comprise the following impurities: at least one of ammonia (NH3), sulfur, chlorine, volatile metals, aromatic tars, tars, fine ashes, and char. Therefore, the objective of the cleaning unit is to the remove or reduce the contents of at least one of the impurities. In one embodiment, the cleaning unit comprises a sulfur removal unit. In one embodiment, the cleaning unit comprises an ammonia removal unit. In one embodiment, the cleaning unit comprises a chlorine removal unit. In some embodiments, the clean syngas comprises less than 5%, less than 4%, less than 3%, less than 2%, or less than 1% by weight of total impurities. In some embodiments, the clean syngas comprises less than 3%, less than 2%, or less than 1% of each impurity species. In one example, impurities include ammonia (NH3), sulfur (as hydrogen sulfide (H2S) and carbonyl sulfide (COS)), chlorine (as HCl), volatile metals, aromatic tars (NBTX; naphthalene, benzene, toluene, and xylene), tars, fines ashes (in the form of particles containing metals and metal salts), bed material, and char (solid particulates typically above 0.001 mm and containing metals, salts and mostly carbon). These impurities, however, limit the ability of the syngas to be used as a fuel or to be employed in the synthesis of other useful materials without a cleaning process.

[0056] Optionally, the clean syngas can be optimized 206. In one embodiment, the optimization step 206, includes adjusting the H:CO ratio of the clean syngas to be between 0.5:1 and 5:1, between 1:1 and 5:1, between 1.5:1 and 5:1, or between 2:1 and 5:1. In some embodiments, the optimization step also includes adding, removing or adjusting the content of CO2 in the clean syngas. The optimization may be performed by providing a H2 gas stream. In some embodiments, the optimization includes further reforming of the syngas. In one example, reforming can be performed as described in WO2020206538 which is incorporated herein by reference.

[0057] The clean syngas is reacted 208 to form the recycled cracked naphtha product slate in a reactor 106 in the presence of a catalyst comprising a mixture of transition metal oxides. A suitable catalyst can be selected based on the recycled cracked naphtha product slate distribution product desired. For example, the catalyst may be selected for a broad C2-C10 specificity, a low C specificity such as C2-C4 or a high C specificity such as C5-C10. In one embodiment, the resulting recycled cracked naphtha product slate mimics the distribution of steam cracked naphtha.

[0058] The present disclosure thus provides a sustainable alternative to produce hydrocarbon value chains (HVCs) using syngas. This is achieved by using a gasification technology that allows waste materials (e.g. waste plastic, MSW with significant amount of single-use-plastic as well as biomass that may include agricultural waste and forestry waste) to convert into syngas followed by a downstream conversion technology according to the present disclosure. In one embodiment, the waste material is rich in biomass (e.g. at least 40%, at least 50%, at least 60%, or at least 70% by weight) and the gasifier contains a fluidized bed to produce the crude synthesis gas.

[0059] The present disclosure provides a waste agnostic method for syngas production and a path forward to transition to a circular economy where the methods and systems of the present disclosure may be retrofitted into existing naphtha dependent assets. The term “agnostic” as used herein means that syngas can be produced regardless of the type of waste (e.g. plastics and non-recyclable plastics, biomass, and municipal solid waste). The recycled cracked naphtha product slate (C2-C10) according to the present disclosure and the production process allows for a sustainable alternative to produce hydrocarbon using syngas without any intermediate. The present direct production of recycled cracked naphtha product slate is more energy-and cost-efficient compared to alternative prior art alternatives such as the FTS.

[0060] The conventional FT synthesis typically produces a mixture of hydrocarbons with broad distributions. In contrast, in some embodiments, the present disclosure aims at the production of liquid fuels (including gasoline, jet fuel and diesel fuel) by refining the FT product or syncrude through complicated catalytic hydrotreatments, such as catalytic or thermal cracking and isomerization in a multi-stage process, which is also H2 consuming and energy-intensive. The direct production according to the present disclosure of a specific range of liquid fuels would be more energy-and cost-efficient and is desirable route. However, with the optimized catalyst HVCs selectivity could be increased by the catalysts by changing the morphology and structure of Fischer-Tropsch metal nanoparticles (e.g., sizes, crystalline phases, and exposed facets), supports, promoters as well as reactors and reaction conditions. In addition, in one example, by optimally choosing the combinations of catalyst where one of the active components of the catalyst is used for cleaving the heavier hydrocarbons formed on FT catalyst components. This mix and match of the catalyst components allows a direct route of products of HVCs more specifically in cracked-naphtha range. In a few examples, the catalyst provides the ability to hydrogenolysis contributing to the cleavage of heavier hydrocarbons. As a consequence, the selectivity of cracked-naphtha range hydrocarbon is increased by breaking the selectivity limitation determined by the Anderson-Schulz-Flory chain-growth-probability model for hydrocarbon distribution. Further, by selecting the appropriate topology, acidity and mesoporosity of materials as well as the metal nanoparticles and support, product selectivity can be improved.

[0061] The Fischer-Tropsch synthesis (FTS) is a highly exothermic reaction producing a wide variety of alkanes:

[0062] In one embodiment, for gasoline-range products, higher temperatures (300°-350° C.) and iron catalysts are used. In another embodiment, for diesel-range and wax products, lower temperatures (200°-240° C.) and cobalt catalysts are used. Operating pressures can be in the range of 10-40 bar. Product distribution can be estimated using the ASF model, in which longer hydrocarbon chains form as the temperature decreases. Without wishing to be bound by theory, at high temperatures, selectivity favors methane and light gases. This can be a disadvantage if liquid fuel production is the focus. Without wishing to be bound by theory, at low temperatures, selectivity favors long-carbon-chain wax products requiring further hydrocracking to the diesel range in a separate unit, which adds more construction cost but is necessary for liquid fuel production. In one example, an iron catalyst can be used to catalyze the water-gas-shift (WGS) at FTS reaction conditions:

[0063] The equilibrium for the above WGS reaction is thermodynamically favored and furthermore, the reverse reaction is slow, compared to the forward reaction, under FTS conditions. However, the forward reaction depends upon the partial pressure of water. For the FTS, a cobalt catalyst produces hydrocarbons and water whereas an iron catalyst (at high conversion), will produce hydrocarbons and carbon dioxide. Thus, for each CH2 produced as hydrocarbon, cobalt will produce a H2Owhereas iron will produce CO2. In this instance, iron will consume two CO molecules for each —CH2— formed whereas the cobalt catalyst will consume only one CO for each —CH2—formed. However, the preferred catalyst, on the basis of the usage of syngas to produce hydrocarbons, will depend only on the economics of whether it is preferable to conduct the WGS reaction in the FT reactor or in a separate operation. At high CO conversions, the WGS reaction is an important component of the synthesis using an iron catalyst and hydrogen is formed in excess of that needed to produce —CH2—.

[0064] In some embodiments, depending on the type of syngas production route and the types of feedstock utilized to generate such syngas as well the techno-economic analysis of the types of hydrocarbons (as high value products) being produced, the choice of either iron (or iron based catalyst) or cobalt (or cobalt based catalyst) can be made.

[0065] Fischer-Tropsch synthesis (FTS) products from the fuel synthesis contain significant amounts of high-molecular-weight wax. Hydrogen is required to crack these high-molecular-weight paraffins to low-molecular-weight hydrocarbons. In one embodiment, the hydro-processing unit such as a hydrocracker for converting the high molecular weight fraction such as wax fractionator followed by a distillation tower for separating naphtha, diesel, and lighter-molecular-weight hydrocarbons can be used to get the desirable product. Methane and propane can be separated and used to fuel the gas turbine in the power generation area. Furthermore, hydrogen can be recycled within this area as needed.

[0066] The temperature for the reaction in the reactor 106 is between 160° C. and 400° C. In one embodiment, the temperature is between 170° C. and 400° C., 180° C. and 400° C., 190° C. and 400° C., 200° C. and 400° C., 160° C. and 390°° C., 160° C. and 380° C., 160° C. and 370° C., 170° C. and 380° C., or 180° C. and 360° C. In one embodiment, the pressure during the reaction in the reactor 106 is between 1 and 100 barg, between 2 and 95 barg, or between 3 and 90 barg. The temperature and pressure can be varied based on the chemical nature of the catalyst selected.

[0067] In some embodiments, the system further comprises a separation unit, to separate the recycled cracked naphtha product slate based on size. For example, a separation unit, such as a separation column or distillation vessel, can be used to separate the C2-C4 olefin from the C5-C10naphtha. In a further example, one or multiple separation steps can be performed to separate the naphtha into each of its component species.EXAMPLE 1

[0068] Sample catalyst A was used in a fixed-bed reactor with a plug-flow behaviour to derive the product-profile that mimic the naphtha crackers. Sample catalyst A contained in weight percent 53.16 O, 6.01 Al, 33.22 Si, 2.98 Fe, 0.75 Na and 6.42 K. The reactor system also included a product analysis unit and liquid collection system. The reactor included a packed bed tubular reactor housed in a furnace with a single heating zone. The reactor tube was made from SS316 stainless-steel (Swagelok) which had an outer diameter of 0.5 inches, an internal diameter of about 0.4 inches, and a length of about twenty-two inches. The reactor was heated using a WATLOW heater equipped with a temperature limit controller. The thermocouple (K-type) having an outer diameter of 0.125 inches was inserted axially through the center of the reactor, which was used to measure and control the temperature within the catalyst bed of approximately 50 mm height. The particle size of the catalyst used were in the range of 0.71 mm to 0.5 mm. No diluents of any kind were used to prepare the catalysts prior to catalytic testing. The catalyst was housed on top of glass beads (Fischer™ Scientific, 5 mm size, 30 g) spaced by glass wool. Pure α-Al2O3 (Sasol™, ten gram) beads (0.5 mm diameter) calcined at 1100° C. were used on either end of the reactor tube before and after the catalyst bed and spaced by the glass wool. In total, the entire length of the reactor tube was filled up (approximately twenty inches) with inert materials to minimize the temperature gradient.

[0069] Further, in order to approach plug flow conditions and minimize back mixing and channeling, certain operating criteria such as the ratio of catalyst bed length to catalyst particle size (L / Dp) was maintained at more than fifty and the ratio of the inside diameter of the reactor to catalyst particle size (D / Dp) was maintained at more than 10. Prior to each experimental run for catalyst evaluation, the catalyst was activated by in situ reduction at 380-450° C. for 2-15 hours by flowing 10% H2 / Ar (Linde™) using a mass flow controller (Bronkhorst™) at atmospheric pressure. The catalyst test was accomplished at temperature ranging from 350° C. to 380° C. Pressure was also varied from 300 to 400 psig. A premixed gas mixture (H2 / CO volume ratio two with 10% CO2 by volume (Linde) was used as a feed. The gas hourly space velocity (GHSV) dictated the volume of gas flow rate depending on the volume of catalyst used in the experiment. Typically, the catalyst amount used was 2.0 grams at a given flow rate. GHSV was defined as volumetric flow of the reactor feed gas divided by the volume of the catalyst bed. The GHSV in mL / h / gcat was calculated asGHSV=Volumetric⁢ flow⁢ rate⁢ (or⁢ feed⁢ flow⁢ rate)mass⁢ of⁢ the⁢ catalyst

[0070] The feed and product gases were analyzed with an on-line gas chromatograph (7890B, Agilent™ Technologies). The GC was equipped with three detectors. The front flame ionization detector (FID) detected hydrocarbons from C1 to C9 and also separated ethane, ethylene, propane, propylene, butane, and butylene using an alumina plot column. The heavier hydrocarbons like aromatics (benzene, toluene, ethylbenzene, p-xylene, o-xylene, m-xylene), oxygenates (methanol, ethanol, and acetones etc.) were detected on another FID which used a CP Wax57 column. The permanent gases (H2, O2 / Ar, N2, CH4, CO, CO2) were detected on a TCD (thermal conductivity detector) and separated on a Haysep and molecular sieve column.

[0071] A chilled water condenser (Lauda™ chiller, operating at 5° C.) was located after the reactor to collect higher hydrocarbon and water condensates. The total gas volume after the reaction was calculated based on Ar that was used as an internal standard in the feed mixture.

[0072] The conversion of CO and selectivity to C2-C4 hydrocarbon, methane, and C5+ and oxygenates such as acetone, methyl ethyl ketone and BTEX were calculated as follows:SC⁢H4(%)=nCH4nCO,in-nCO,out×100SC2-C4⁢hydrocarbon(%)=nC2⁢H6+nC3⁢H8⁢nC2⁢H6+nC2⁢H4+nC3⁢H6+nC4⁢H8nCO,in-nCO,out×100SC5+(%)=nC5+nCO,in-nCO,out×100Sa⁢r⁢o⁢m⁢a⁢t⁢i⁢c⁢s+oxygentates(%)=na⁢r⁢o⁢m⁢a⁢t⁢i⁢c⁢s+o⁢xygentatesnCO,in-nCO,out×100YC⁢2-C⁢4h⁢ydrocarbon(mol⁢ %)=SC2-C4⁢hydrocarbon×XC⁢O÷100YC5+(mol⁢ %)=SC5+×XCO÷100nCO,in is the moles of CO input. nCO,out is the moles of CO output. nC<sub2>2< / sub2>H<sub2>4 < / sub2>is the moles of C2H4 output while nC<sub2>2< / sub2>H<sub2>6 < / sub2>is the moles of C2H6 output while nC<sub2>3< / sub2>H<sub2>8 < / sub2>is the moles of C3H8 output while nC<sub2>4< / sub2>H<sub2>10 < / sub2>is the moles of C4H10 output while, nCH<sub2>4 < / sub2>is the moles of CH4 output. Again the nC<sub2>5+< / sub2> is the moles of C5+ output.The syngas flow was controlled using a mass flow meter to get a certain composition of gas mixture. This was then fed to the reactor via a three-way valve. The valve allows to switch the feed to bypass while needed. The back pressure regulator (BPR) allows to control the reactor pressure. For all reporting data, the carbon balances were higher than 95%, and the selectivity were normalized to one hundred. The gas composition of the syngas getting into the reactor was as follows: 60% by volume H2, 30% by volume CO and 10% by volume CO2 having a GHSV of 1500 mL / h / gcat. for the overall gas feed.EXAMPLE 2

[0074] Using the method as described in Example 1, sample catalyst B was also tested under the conditions established. Sample catalyst B contained in weight percent 55.5 0, 7.2 Al, 33.2 Si, 3 Fe, 1 Zn, and 0.1 K.

[0075] A recycled cracked naphtha product slate was obtained from a method according to the present disclosure as presented in Example 1 and Example 2 is summarized in Table 1. The product distribution of Example 1 and Example 2 were also compared to other known processes such as Fisher-Tropsch Synthesis (FTS) and methanol to olefins-MTO processes as reported in literature (Table 1).TABLE 1Yields by weight % (CO2 free basis)Hydrogen &C2-C4Oxygenates &C5 plusProcessMethaneHydrocarbonaromaticshydrocarbonExample 1 (Sample A)19%41%10%30%(Direct syngas approach)Example 2 (Sample B)29%44% 9%18%(Direct syngas approach)Product slate of naphtha25%55%12% 8%cracker (Ref 3)Comparative example 2%98%nonenone(MTO-OCP / MTP)Methanol to olefin -Olefin cracking process / methanol to propylene(Ref 2)Comparative examplenonenonenoneNaphtha = 13%Syngas to hydrocarbonsDiesel = 37%(Fisher-Tropsch based) -Wax = 50%(Ref 1)

[0076] While the present disclosure has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modifications and this application is intended to cover any variations, uses, or adaptations, including such departures from the present disclosure as come within known or customary practice within the art and as may be applied to the essential features hereinbefore set forth, and as follows in the scope of the appended claims.REFERENCES1. https: / / openknowledge.worldbank.org / handle / 10986 / 21976

[0078] 2. Methanol to Olefins, SRI Consulting Report Number 261, November 2007

[0079] 3. Chemical Engineering Journal 176-177 (2011), 178-197

Claims

1-14. (canceled)15. A method of producing a recycled cracked naphtha product slate, the method comprising:gasifying a waste material to obtain a crude syngas, the waste material comprising carbon and hydrogen in a molar ratio H:C;cleaning the crude syngas to obtain a clean syngas comprising H2 and CO in a molar ratio H2:CO of between 0:5:1 and 5:1; andreacting the clean syngas in the presence of a catalyst comprising a mixture of transition metal oxides to obtain the recycled cracked naphtha product slate,wherein the molar ratio H:C is less than 2.

516. The method according to claim 15, wherein the waste material is selected from at least one of consisting of municipal solid waste (MSW), commercial solid waste, institutional solid waste, plastic waste, homogenous solid biomass, non-homogeneous solid biomass, and combinations thereof.

17. The method according to claim 16, wherein said waste material is diapers.

18. The method according to claim 16, wherein said waste material is single use waste plastics.

19. The method according to claim 15, further comprising, reforming the crude synthesis gas and / or the clean synthesis gas to adjust the H2:CO ratio.

20. The method according to claim 15, wherein cleaning comprises quenching, scrubbing, and adsorbing the crude syngas.

21. The method according to claim 15, wherein the step of cleaning comprises removing at least one of ammonia (NH3), sulfur, chlorine, volatile metals, aromatic tars, tars, fine ashes, and char.

22. The method according to claim 15, further comprising recycling at least a portion of the waste material generated by the reactor to the gasifier.

23. The method according to claim 15, wherein the recycled cracked naphtha product slate comprises less than 10% of methane.

24. The method according to claim 15, wherein the step of reacting the clean syngas is performed at a temperature of between 160° C. and 400° C. and / or at a pressure of between 1 and 100 barg.

25. (canceled)26. The method according to claim 15, further comprising separating the recycled cracked naphtha product slate into different hydrocarbon compositions.

27. The method according to claim 26, further comprising separating higher carbon molecules from the recycled cracked naphtha product slate and feeding said higher carbon molecules into a naphtha cracker producing lower olefins, and / or further comprising separating the lighter carbon molecules from the recycled cracked naphtha product slate and mixing said lighter carbon molecules with lower olefins recovered from the naphtha cracker.

28. (canceled)29. A system for producing a recycled cracked naphtha product slate in accordance to the method of claim 1, the system comprising:a gasifier to gasify a waste material comprising carbon and hydrogen in a molar ratio H:C, to produce a crude syngas;a cleaning unit to clean the crude syngas and produce a clean syngas comprising H2 and CO in a molar ratio H2:CO of between 0.5:1 to 5:1; anda reactor comprising a catalyst to produce the recycled cracked naphtha product slate from the clean syngas, the catalyst comprising a mixture of transition metal oxides,wherein the molar ratio H:C in the gasifier is less than 2.5.

30. The system according to claim 29, wherein the waste material is selected from municipal solid waste (MSW), commercial solid waste, institutional solid waste, plastic waste, homogenous solid biomass, non-homogeneous solid biomass, and a combination thereof.

31. The system according claim 29, wherein the gasifier comprises a fluidized bed, a fixed bed, a slurry phase and / or a reforming section.

32. The system according to claim 29, further comprising a storage unit for storing the waste material.

33. The system according to claim 29, further comprising a recycling stream from the reactor to the gasifier.

34. The system according to claim 29, further comprising a separation unit to separate different hydrocarbon components of the recycled cracked naphtha product slate.

35. The system according to claim 29, wherein the catalyst comprises in weight percent 53.16 O, 6.01 Al, 33.22 Si, 2.98 Fe, 0.75 Na and 6.42 K.

36. The system according to claim 29, wherein the catalyst comprises in weight percent 55.5 0, 7.2 Al, 33.2 Si, 3 Fe, 1 Zn, and 0.1 K.

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