Methods and Design for Production of Cracked- Naphtha Range Hydrocarbon from Waste Carbon Materials

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.

The disclosure relates to the field of producing recycled cracked naphtha product slate from a waste material.

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 H/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 H/CO ratio greater than 2. However, more sustainable processes and green technologies are desired to produce cracked naphtha.

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.

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 H, CO and COthat are wasted and offer limited economic advantage. Therefore, the sustainability of such processes is limited.

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 Cthat may include oxygenates including methanol and DME. However, none of these proposed processes achieve adequate sustainability.

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

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

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.

In one embodiment the waste material is diapers.

In one embodiment the waste material is single use waste plastics.

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

In one embodiment the gasifier comprises a reforming section.

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

In one embodiment the cleaning unit comprises a scrubbing column.

In one embodiment the cleaning unit comprises an adsorption column.

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

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

In one embodiment the recycled cracked naphtha product slate comprises at least 90% by weight of C-Chydrocarbons on a COfree basis.

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

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

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

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

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

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

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

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

In one embodiment the method further comprises separating the recycled cracked

naphtha product slate into different hydrocarbon compositions.

In one embodiment the method further comprises separating higher carbon molecules

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

In one embodiment the method further comprises 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.

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.

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.

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

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).

Making reference to, there is provided a systemcomprising a gasifier, a cleaning unitand a reactor, 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 C-C. For example, the recycled cracked naphtha product slate can comprise in weight percent, at least 90%, 93%, 95%, 96%, 97%, or 98% of C-C. 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 C-C, C-C, C-C, or C-C. 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.

Naphtha obtained during the atmospheric distillation of crude oil has the following composition: C-C(8%), C(22%), C(20%), C(18%), C(12%), C(11%), C-C(9%). Distilled naphtha is a C-Chydrocarbon 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%), Hand CH(25%), propylene (13%), butadiene (2%), mixed butene (8%), Chydrocarbon (8%) and aromatics (11%), a product slate that provides a C-Chydrocarbon. 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 C-C. 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%.

Also making reference to, 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, cleaningthe crude syngas to obtain a clean syngas, optionally optimizingthe syngas, and reactingthe 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 (H/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 CO. Therefore, the conversion of waste natural gas (H:C of about 4) will ultimately result in less COproduction 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 H/COratio via the water-gas shift reaction. This could result in higher H/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 COfootprint). Specifically, syngas produced from biomass has a significantly lower H/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.

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 systemor can be transported to the systemand 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.

The waste materials are converted to syngas by gasificationin the gasifier. 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 (CO) and hydrogen (H). 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.

Syngas is an important feedstock in the chemical industry. It is a gas mixture comprising primarily of hydrogen (H) and carbon monoxide (CO) and may further contain other gas components such as carbon dioxide (CO), water (HO), methane (CH) and/or nitrogen (N). 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.

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.

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.

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.

Following the gasification, the crude syngas is cleanedusing a cleaning unit. The cleaning unitcomprises one or more cleaning columns for example a separation column, an adsorption column and/or a scrubbing column. The cleaning step, 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 (NH), 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 (NH), sulfur (as hydrogen sulfide (HS) 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.

Optionally, the clean syngas can be optimized. In one embodiment, the optimization step, 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 COin the clean syngas. The optimization may be performed by providing a Hgas 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.

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 C-Cspecificity, a low C specificity such as C-Cor a high C specificity such as C-C. In one embodiment, the resulting recycled cracked naphtha product slate mimics the distribution of steam cracked naphtha.

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.