INTERNAL HEAT GENERATING MATERIAL COUPLED HYDROCARBON CRACKING

A method of cracking a hydrocarbon feed which includes introducing vaporizing a hydrocarbon feed and a heat generating material (HGM) stream comprising at least one aldehyde or ketone to a cracking reactor. The hydrocarbon feed and the HGM stream are vaporized and may be vaporized prior or subsequent to introduction to the cracking reactor. The addition of the HGM to the endothermic cracking process provides the heat needed for cracking and helps the overall process to achieve thermal neutrality. The method includes cracking the hydrocarbon feed to produce a cracking product, where the cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons.

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Description
CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser. No. 62/335,187 filed May 12, 2016, incorporated herein by reference.

BACKGROUND Field

Embodiments of the present disclosure generally relate to processing of hydrocarbons, and specifically relate to a method of cracking a hydrocarbon feed with a heat generating material coupled hydrocarbon cracking process.

Technical Background

Energy consumption is a significant obstacle in the light olefins industry. Hydrocarbon cracking is a highly endothermic process. During a hydrocarbon cracking process, the temperature of the reactor housing drops as the cracking reaction is initiated, because the activation of the endothermic cracking process consumes heat faster than the reactor adds additional heat. Adding the additional heat to maintain the reactor temperature adds significant costs to hydrocarbon cracking operations. For example, current steam-cracking processes operate at 800-1000° C., consuming as much as 40% of the energy used by the entire petrochemical industry. Specific energy consumption is about 4500-5000 kcal/kg of ethylene for the most up-to-date steam-crackers. Overall, about 70% of production costs in typical ethane- or naphtha-based olefin plants are due to energy consumption.

SUMMARY

Against the above background, ongoing needs exist for the development of efficient and economical routes to crack hydrocarbon feeds to yield high demand petrochemical building blocks.

Embodiments of the present disclosure are directed to methods of cracking a hydrocarbon feed using exothermic heat generating materials (HGM) to fuel the energy requirements of endothermic hydrocarbon cracking processes. The methods and systems of the present disclosure have industrial applicability, specifically in the oil and gas industries due to the high energy costs traditionally required for hydrocarbon cracking. Without being limited to theory, the HGMs of the present disclosure are added to help the hydrocarbon cracking process become energy neutral or approach energy neutrality, thereby reducing the overall energy costs associated with hydrocarbon cracking.

According to one embodiment, a method of cracking a hydrocarbon feed is provided. The method includes vaporizing a hydrocarbon feed and vaporizing a heat generating material (HGM) stream comprising at least one aldehyde or ketone. Further, the method includes introducing the vaporized hydrocarbon feed and the vaporized heat generating material stream to a cracking reactor. Finally, the method also includes cracking the hydrocarbon feed to produce a cracking product, where the cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons. The cracking product may include ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils.

According to another embodiment, a method of cracking a hydrocarbon feed is provided. The method includes vaporizing a hydrocarbon feed and vaporizing a heat generating material (HGM) stream comprising at least one aldehyde or ketone. Further, the method includes heating the vaporized hydrocarbon feed and vaporized HGM stream to a pre-reaction temperature of at least 100° C. and introducing the vaporized hydrocarbon feed and the vaporized heat generating material stream to a cracking reactor. Finally, the method also includes cracking the hydrocarbon feed to produce a cracking product, where the cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons. The cracking product may include ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils.

According to yet another embodiment, a method of cracking a hydrocarbon feed is provided. The method includes introducing a hydrocarbon feed and a heat generating material (HGM) stream comprising at least one aldehyde or ketone to a cracking reactor. The method further includes vaporizing the hydrocarbon feed and the heat generating material stream within the cracking reactor. Finally, the method also includes cracking the hydrocarbon feed to produce a cracking product, where the cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons. The cracking product may include ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils.

Additional features and advantages of the described embodiments will be set forth in the detailed description which follows, and in part will be readily apparent to those skilled in the art from that description or recognized by practicing the described embodiments, including the detailed description which follows, the claims, as well as the appended drawings.

It is to be understood that both the foregoing general description and the following detailed description describe various embodiments and are intended to provide an overview or framework for understanding the nature and character of the claimed subject matter. The accompanying drawings are included to provide a further understanding of the various embodiments, and are incorporated into and constitute a part of this specification. The drawings illustrate the various described embodiments, and together with the description serve to explain the principles and operations of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic illustration of a lab-scale reactor system for operation in accordance with one or more embodiments of the present disclosure.

FIG. 2 is a temperature profile of the catalyst bed temperature with and without the heat generating material feed at a reaction temperature of 560° C.

FIG. 3 is a temperature profile of the catalyst bed temperature with and without the heat generating material feed at a reaction temperature of 584° C.

 DETAILED DESCRIPTION

Reference will now be made in detail to embodiments for the improved cracking of a hydrocarbon feed using the HGMs of the present disclosure. As stated previously, hydrocarbons cracking is an endothermic process. By coupling the hydrocarbons cracking reaction with HGMs, the traditionally endothermic cracking process can become thermally neutral or approach thermal neutrality. Specifically, the HGMs generate exothermic heat when included in the hydrocarbon cracking processes of the present disclosure. This exothermic heat may provide additional heat needed for the endothermic hydrocarbon cracking process. Moreover, the HGM may also act as a diluent to prevent coking while also acting as an oxidant to promote hydrocarbon cracking. The hydrocarbon cracking system of FIG. 1 is a laboratory set-up provided for the present discussion, which follows; however, it should be understood that the present systems and methods encompass other configurations including large-scale and industrial process schemes.

Referring to the embodiment of FIG. 1, a laboratory scale hydrocarbon cracking system 100 for cracking a hydrocarbon feed 4 is shown. Specifically, the hydrocarbon cracking system 100 performs catalytic hydrocarbon cracking of a hydrocarbon feed 4 in the presence of a heat generating material (HGM) stream 2.

The hydrocarbon feed 4 may refer to any hydrocarbon source derived from petroleum, coal liquid, or biomaterials. Example hydrocarbon sources include whole range crude oil, distilled crude oil, residue oil, topped crude oil, liquefied petroleum gas (LPG), naphtha, gas oil, product streams from oil refineries, product streams from steam cracking processes, liquefied coals, liquid products recovered from oil or tar sands, bitumen, oil shale, biomass hydrocarbons, and the like. In specific examples, which will be described in subsequent paragraphs, the hydrocarbon feed 4 may include n-hexane, naphtha, mixed butenes, ethylene, and their combinations.

Mixed butenes are traditionally considered lower value streams than propylene and ethylene. Pure butene-1 has value for polyethylene production, but because of the technical difficulties in separating it from mixed butene streams, butene-1 is usually produced selectively from direct methods such ethylene dimerization to butene-1. Demand for propylene has increased more than the demand for ethylene so ethylene sales may be cut back and the residual ethylene be fed back into the cracking reactor to produce more propylene. The feed stream to the hydrocarbon cracking process may be adjusted based on the demand for products to generate the most desirable final production.

The HGM stream 2 may include various components utilized to generate exothermic heat which may be used in the cracking process. In one or more embodiments, the HGM comprises at least one aldehyde or ketone. In one or more embodiments, the aldehyde is a formaldehyde. As formaldehyde is gaseous at room temperature, it is typically distributed as 37% by mass dissolved in water. This mixture is commonly known as 100% formalin. As a stabilizer, methanol may be added to the formalin to prevent oxidation and polymerization. Without being limited to theory, formaldehyde with methanol performs well as an HGM, because it was surprisingly found that the predictable side reactions, such as the conversion of formaldehyde to CO and H2 are inhibited by the simultaneous additions of hydrocarbons.

In one or more embodiments, additional HGM stream 2 components beyond a ketone or aldehyde, such as formaldehyde, may include one or more additional aldehydes, additional ketones, or alcohols. Mixing multiple aldehydes, ketones, alcohols, or their combinations helps promote or hinder selectivity to certain reaction products. For example, as the ratio of additional aldehydes, ketones, or alcohols to formaldehyde or other aldehyde is varied the reactions products may shift toward or away from light olefins.

Various concentrations of the formaldehyde in the formalin and methanol mixture are contemplated. For example, the formalin (37 weight % formaldehyde in water) may be used in undiluted or diluted form in order to achieve the desired concentration necessary for the space velocity of the specific cracking reaction. In one or more embodiments, the HGM 2 may comprise 5 to 37 weight % formaldehyde, or 10 to 37 weight % formaldehyde, or 20 to 37 weight % formaldehyde, or 25 to 37 weight % formaldehyde. Components of the HGM stream 2 may be obtained from renewable sources. Specifically, components such as aldehydes, ketones, and alcohols may be obtained from a fermentation process of biomass or syngas processes.

Referring again to FIG. 1, the hydrocarbon cracking system 100 may comprise a reactor system having at least one catalyst bed reactor 10, and optionally, additional reactors and units. For example, these additional optional units may include a preheater reactor 12 connected to the at least one catalyst bed reactor 10 and additional heaters or heat exchangers 18. At an industrial scale, the hydrocarbon cracking system 100 may also comprise a reactor system without a catalyst bed reactor. For example, a hydrocarbon cracking system 100 utilizing thermal cracking without a catalyst is envisioned.

As shown in the laboratory scale lab-scale reactor system of FIG. 1, the catalyst bed reactor 10 may include a solid acid catalyst bed 14 disposed in the catalyst bed reactor 10. As stated previously, the operation of the catalyst bed reactor 10 results in the cracking of the hydrocarbon feed 4 to produce a cracking product 40, where the cracking product 40 comprises light C1-C4 hydrocarbons, such as ethylene and propylene, and heavy C5+ hydrocarbons. The cracking product 40 may include ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils. The particular combination of products in the cracking product 40 depends on the constituents of the feed to the catalyst bed reactor 10. Adding the HGM stream 2 to the catalyst bed reactor 10 reduces or eliminates the additional heat energy input requirements in the catalyst bed reactor 10. Specifically, the HGM stream 2 undergoes an exothermic reaction in the catalyst bed reactor 10 which offsets the endothermic cracking process yielding a thermally neutral overall hydrocarbon cracking operation. Varying the make-up, the flow rate, or both the make-up and the flow rate of the HGM stream 2 may yield an overall hydrocarbon cracking operation that is thermally negative to thermally neutral to thermally positive.

Various components are contemplated for the solid acid catalyst bed 14 of the catalyst bed reactor 10. In one or more embodiments, the solid acid catalyst bed 14 may include an aluminosilicate zeolite, a silicate (for example, silicalites), or a titanosilicate. In further embodiments, the solid acid catalyst is an aluminosilicate zeolite having a Mordenite Framework Inverted (MFI) structure. For example and not by way of limitation, the MFI structured aluminosilicate zeolite catalyst may be a ZSM-5 catalyst. In a further embodiment, the ZSM-5 catalyst may be an H-ZSM-5 catalyst where at least a portion of the ZSM-5 catalyst ion exchange sites are occupied by H+ ions. Moreover, the aluminosilicate zeolite catalyst, for example, the H-ZSM-5 catalyst, may have a Si/Al molar ratio of at least 10. In further embodiments, aluminosilicate zeolite catalyst may have a Si/Al molar ratio of at least 30, or at least 35, or at least 40. Additionally, the aluminosilicate zeolite catalyst may also include one or more additional components used to modify the structure and performance of the aluminosilicate zeolite catalyst. Specifically, aluminosilicate zeolite catalyst may include phosphorus, boron, nickel, iron, tungsten, other metals, or combinations thereof. In various embodiments, the aluminosilicate zeolite catalysts may comprise 0-10% by weight additional components, 1-8% by weight additional components, or 1-5% by weight additional components. For example and not by way of limitation, these additional components may be wet impregnated in the ZSM-5 followed by drying and calcination. The aluminosilicate zeolite catalysts may contain mesoporous structures. The catalyst may be sized to have a diameter of 25 to 2,500 micrometers (μm). In further embodiments, the catalyst may have a diameter of 400 to 1200 μm, 425 to 800 μm, 800 to 1000 μm, or 50 to 100 μm. The minimum size of the catalyst particles depends on the reactor design to prevent passage of catalyst particles through the filter with reaction products.

In one or more embodiments, the catalyst bed reactor 10 may be a fixed-bed reactor, a fluidized bed reactor, a slurry reactor, or a moving bed reactor. In a specific embodiment, the catalyst bed reactor 10 is a fixed-bed reactor. In some embodiments with a fixed bed reactor, the residence time of the combined hydrocarbon feed 4 and the heat generating material stream 2 in the catalyst bed reactor 10 is in the range of 0.05 seconds to hour. For example, the residence time may approach 1 hour for diesel hydrotreating a liquid feed and is generally in the range of 0.1 to 5 seconds in an FCC application. As such, in various embodiments, the residence time in the catalyst bed reactor 10 is 0.1 seconds to 5 seconds or 5 minutes to 1 hour. The desired residence time in a fixed bed reactor of the combined hydrocarbon feed 4 and the heat generating material stream 2 for optimal hydrocarbon cracking is dependent on operating temperature and composition of both the solid acid catalyst bed 14, the hydrocarbon feed 4, and the heat generating material stream 2. Additionally, in one or more embodiments, the bed voidage, which represents the volume fraction occupied by voids, is between 0.2 and 1.0. In further embodiments, the bed voidage is between 0.3 and 0.8.

The catalyst bed reactor 10 may have an operating temperature of 250 to 850° C. In further embodiments, the catalyst bed reactor 10 has an operating temperature of 450 to 650° C., or 540 to 560° C., or 575 to 595° C. Without being limited to theory, the addition of the HGM 2 is believed to improve the catalyst life of the solid acid catalyst bed 14. The HGM 2 acts as a diluent and oxygenates the hydrocarbon feed to prevent coking.

Moreover, the solid acid catalyst bed 14 may be preheated in a gas flow containing heated nitrogen 6 and oxygen at sufficient flow rate to heat the solid acid catalyst bed 14. The oxygen may be provided as air. The preheated gas flow is heated from 250 to 650° C., or from 475 to 525° C., or from 490 to 510° C. in various embodiments.

Referring to FIG. 1, a laboratory scale reactor system, the method further may include preheating the hydrocarbon feed 4 upstream of the catalyst bed reactor 10. This preheating of the hydrocarbon feed 4 may be achieved in a preheater reactor 12. As shown, the hydrocarbon fed 4 may be heated in the presence of nitrogen 6. In one embodiment, the preheater reactor 12 may raise the temperature of the hydrocarbon feed 4 being supplied to the catalyst bed reactor 10 to a pre-reaction temperature of at least 100° C. The hydrocarbon feed 4 is typically heated to a pre-reaction temperature of 200-300° C. This range of the pre-reaction temperature is maintained low enough to prevent thermal cracking in the preheater reactor 12 before the catalyst bed reactor 10. Conversely, the pre-reaction temperature is elevated enough that a cold hydrocarbon feed 4 does not cause the catalyst bed 14 proximal the entrance to the catalyst bed reactor 10 to cool and affect total conversion of the hydrocarbon feed 4. In one or more embodiments, the hydrocarbon cracking system 100 may also optionally include at least one hydrocarbon preheater 18 disposed upstream of the preheater reactor 12. The hydrocarbon preheater or preheaters 18, as shown in FIG. 1, raises the temperature of the hydrocarbon feed being supplied to the at least one preheater reactor 12. The preheaters 18 may include a heat exchanger or a similar heater device familiar to one of ordinary skill in the art.

The hydrocarbon cracking system 100 may also include at least one heat generating material preheater 16 disposed upstream of the catalyst bed reactor 10. The heat generating material preheater 16 raises the temperature of the heat generating material stream 2 being supplied to the at least one catalyst bed reactor 10. In embodiments, the heat generating material preheater 16 raises the temperature of the heat generating material stream 2 to a pre-reaction temperature of at least 100° C. The maximum pre-reaction temperature of the heat generating material stream 2 is limited by the cracking temperature of the heat generating material stream 2 so that thermal cracking of the heat generating material stream 2 does not occur before the catalyst bed reactor 10. In laboratory or pilot scale reactors, the hydrocarbon cracking system 100 also may also include other heating components as shown. For example, the hydrocarbon cracking system 100 may include a reactor oven 20, or a hot box 22 surrounding the catalyst bed reactor 10, the preheater reactor 12, the heat generating material preheater 16, and the hydrocarbon preheater 18. The reactor oven 20 may help maintain the temperature of the catalyst bed reactor 10 and the preheater reactor 12. Similarly, the hot box 22 serves to retain heat around the catalyst bed reactor 10, the preheater reactor 12, the heat generating material preheater 16, and the hydrocarbon preheater 18 so as to reduce thermal losses.

The hydrocarbon preheater 19, the preheater reactor 12, and the heat generating material preheater 16 may also be combined into a single preheater to raise the temperature of both the hydrocarbon feed 4 and the heat generating material stream 2 before entering the catalyst bed reactor 10.

In an industrial scale operation, the hydrocarbon feed 4 and the heat generating material stream 2 are heated until the hydrocarbon feed 4 and heat generating material stream 2 are respectively vaporized. The hydrocarbon feed 4 and the heat generating material stream 2 may be mixed together and vaporized concurrently in a single feed preheater. Alternatively, the hydrocarbon feed 4 and the heat generating material stream 2 may be independently vaporized with separate feed preheaters before being combined and fed to a cracking reactor. Subsequently, heated steam or other diluent may be injected into the vaporized hydrocarbon feed 4, the vaporized heat generating material stream 2, or a combined vaporized stream of the hydrocarbon feed 4 and the heat generating material stream 2 before being fed into the cracking reactor. Providing a diluent to the feed to the cracking reactor spaces the molecules of the hydrocarbon feed 4 out. It will be appreciated that when formalin (37 weight % formaldehyde in water) is used as a constituent of the heat generating material stream 2, the addition of steam or other diluent may be unnecessary as formalin comprises water which is converted to steam during vaporization of the heat generating material stream 2. It may also be appreciated that vaporization of the hydrocarbon feed 4 and heat generating material stream 2 may be achieved inside the cracking reactor and not prior to injection into the reactor.

Moreover, balancing the amounts of the heat generating materials stream 2 and the hydrocarbon feed 4 may facilitate a thermally neutral cracking process. In further embodiments, the HGM stream 2 and the hydrocarbon feed 4 are fed to the catalyst bed reactor 10 at a weight ratio of 1:10 to 10:1. In further embodiments, the heat generating material stream 2 and the hydrocarbon feed 4 are fed to the catalyst bed reactor 10 at a ratio of 1:6 to 6:1, 1:3, to 3:1, or 1:2 to 2:1. In yet further embodiments, the heat generating material stream 2 and the hydrocarbon feed 4 are fed to the catalyst bed reactor 10 at a ratio of 2:3 to 3:2.

Referring again to FIG. 1, the cracking product 40 may comprise a variety of light C1-C4 hydrocarbons and heavy C5+ hydrocarbons. In one or more embodiments, the cracking product 40 specifically comprises propylene, butenes such as 2-trans-butene, n-butene, iso-butene and 2-cis-butene, C5 olefins, aromatics, methane, ethane, propane, butanes, and pentane. The constituents of the cracking product 40 are dependent upon the components of the hydrocarbon feed 4 and the heat generating material stream 2. For example, formaldehyde not only provides heat to offset the endothermic cracking process, but also is an effective reactant to produce light olefins.

To separate light hydrocarbons from heavy hydrocarbons in the cracking product 40, the hydrocarbon cracking system 100 may also include a condenser and at least one liquid/gas separator 24. The liquid/gas separator 24, which may include a flash drum or the like. The cracking product 40 is fed to a condenser upon exiting the cracking reactor where the temperature of the gaseous cracking product 40 is reduced and is partially condensed. The partially condensed feed is subsequently fed to the liquid/gas separator 24 where the liquid and gas phases are separated. Specifically in the liquid/gas separator 24, the light hydrocarbon stream 42 may be separated as gas phase light hydrocarbons, while the liquid phase heavy hydrocarbon stream 44 are separately discharged from the liquid/gas separator 24. Further, at an industrial scale, to separate light hydrocarbons from heavy hydrocarbons in the cracking product 40, the hydrocarbon cracking system 100 may include multi-product distillation columns. Industrial scale separation utilizing distillation columns, stripping columns, or extraction columns and other methods and processes for handling and separating product streams are known to one having skill in the art and may be equally utilized.

Further reactions are contemplated to separate the desired propylene and ethylene from the light hydrocarbon stream 42. For example, the light hydrocarbon stream 42 may be cooled and collected as a liquid hydrocarbon product. At which point, propylene and ethylene may be separated via a distillation, extractive distillation or membrane separation methodology.

In further embodiments, the rate of total flow of the HGM stream 2, hydrocarbon feed 4, and steam or other diluents supplied to the hydrocarbon cracking system 100 is adjusted to control the space velocity of the reaction. The weight hourly space velocity (WHSV) is defined as the flow of reactants, for example, in grams/hour (g/hr), divided by weight the catalyst weight, for example, in grams (g). The flow of reactants includes the total flow of the HGM stream 2, hydrocarbon feed 4, and steam or other diluents. In one or more embodiments, the weight hourly space velocity of the reaction is 0.01 to 100 hours−1 (h−1). In further embodiments, the weight hourly space velocity of the reaction is 1 to 8 hours−1, 2 to 4 hours−1, or 2.8 to 3.4 h−1.

Ethylene and propylene are two of the main petrochemical building blocks used in various applications, for example, the production of plastics and synthetic fibers. Specifically, ethylene is extensively used to manufacture polyethylene, ethylene chloride and ethylene oxide which are very useful for the packaging, plastic processing, construction and textile industries. Further, propylene is commonly used to make polypropylene, but it is also a basic product necessary to produce propylene oxide, acrylic acid and many other chemical derivatives. Plastic processing, the packaging industry, the furnishing sector, and the automotive industry are frequent users of propylene and its derivatives. Thus, increasing yields of light olefins such as ethylene and propylene to supply the numerous industrial users is desirable.

The improved conversion of the hydrocarbon feed 4 and light olefin (for example, ethylene and propylene) yields are validated with experimental testing. Hexane was provided to an experimental set-up of the hydrocarbon cracking system 100 under varying conditions and with varying heat generating material stream 2 ratios.

Examples

The following examples are illustrative of the present embodiments and are not intended to limit the scope of the described embodiments of the disclosure.

Experimental data was obtained to demonstrate the effect of coupling hydrocarbon cracking reactions with HGMs. Catalytic reactions were carried out in a fixed-bed flow reactor operated at atmospheric pressure. Catalyst having a mass of 9 to 12 g, which had been palletized and sieved to 425-800 micrometers (μm) in diameter, was loaded into the reactor. The catalyst was microporous molecular sieves of ZSM-5 purchased from Nankai University Catalyst Co. Before the catalytic reactions, the catalyst was activated in a gas flow containing N2 (120 cm3 min−1) to the desired reaction temperature and held overnight. The fixed-bed flow reactor was heated using 3 zone electric heater to the desired reaction temperature. At the desired reaction temperature (typically between 250-850° C.), the reactants, selected from n-hexane, naphtha, and formaldehyde (37% solution stabilized in 13.88% of methanol) were introduced into the reactor to start the reaction

The products from the catalytic reaction were analyzed by an online gas chromatograph equipped with an Agilent HP-Al/KCl (50 m×0.53 mm ID, 15 μm) column and detected by a Flame Ionization Detector (FID) detector. N2, CH4, C2H6, C2H4, C3H8, C3H6, n-C4H10, i-C4H10, 1-C4H8, 2-cis-C4H8, 2-trans-C4H8, i-C4H8, n-C5H12, and n-C5H6 were used as calibration standards. All the lines and valves between the exit of the fixed bed flow reactor and the gas chromatographs were heated to 105° C. to prevent condensation of heavier hydrocarbons.

Liquid products were collected separately using a low pressure liquid/gas separator. The organic part, if any, was separated from water and its compositions were analyzed by gas chromatography mass spectroscopy (GCMS) to identify the products and followed by gas chromatography (GC) to determine their concentrations.

The conversion of hexane was determined as a weight percentage. The conversion is defined as the percentage of the weight of hexane converted into final products. The equation for the conversion of hexane is provided as equation (1) with Wi being the weight of hexane injected and Wf being the weight of unreacted hexane detected by GC.


Conversion %=100×(Wi−Wf)/Wi  (1)

Additionally the weight hourly space velocity (WHSV), as previously define, was maintained at a constant for a subset of tests to compare the HGM effects.

During experimentation, the normal reaction time was 35 minutes. After reaction, the catalyst bed was purged with high purity nitrogen at a flowrate of 0.2 liters/min for 30 minutes to flush away all reaction products and hydrocarbons before introducing air. Introduction of air is delayed as it may be a combustion hazard in the presence of hydrocarbons and reaction products. Subsequent to flushing with nitrogen to remove reaction products and hydrocarbons, the catalyst was regenerated using an air flow rate of 0.154 lit/min for 1 hour or until the temperature stabilized. After that the catalyst bed was flushed with nitrogen again for 30 minutes to remove combustion products

Tests were run with hexane as the hydrocarbon feed 4 in combination with formaldehyde as the heat generating material stream 2 to demonstrate the effect of the heat generating material. Each test was run for 35 minutes. Table 1 details various cracking process parameters for the cracking product 40 when formaldehyde is present and when formaldehyde is not present. The coupling of the hexane and formaldehyde results in an increased C6 conversion, ethylene yield, and propylene yield.

TABLE 1 Varying Formaldehyde Ratio (Reaction Temperature = 584° C.) C6/ C6 Ethylene Propylene Formal- Conversion Yield % Yield % dehyde WHSV % (E) (P) E + P P/E 1:0 3.1 71 9.9 16.9 26.8 1.7 1:0.5 3.1 67 10 18 28 1.8 1:2 3.1 84 19 25 44 1.3

The increased ethylene and propylene yield when the heat generating material stream 2 is provided in conjunction with the hydrocarbon feed 4 is desirable. Additionally, Table 2, provided as follows, details various cracking process parameters for the cracking product 40 when formaldehyde is present and the residence time is varied. Each test was run for 35 minutes. An increased residence time results in an increased C6 conversion.

TABLE 2 Varying residence time (Reaction Temperature = 584° C.) C6/ C6 Ethylene Propylene For- Conversion Yield % Yield % maldehyde WHSV % (E) (P) E + P P/E 1:2 6.2 42 18 34 52 1.8 1:2 3.1 84 21 27.8 48.8 1.3

The thermal neutrality of the hydrocarbon cracking process when the heat generating material stream 2 is added may be seen with FIGS. 2 and 3. Specifically, FIG. 2 demonstrates that when hexane and the heat generating material are provided at a 2:1 ratio the resulting drop in temperature of the solid acid catalyst bed 14 is reduced. The temperature bed of the solid acid catalyst bed 14 drops very vast when introducing the hexane feed and a controller then responds by increasing the wall temperature of the catalyst bed reactor 10. With just a hexane feed (hydrocarbon feed 4) and no heat generating material, the wall temperature doesn't increase as fast as the temperature drops in the catalyst bed reactor 10 from the endothermic reaction. Conversely, with a concurrent heat generating material stream 2 being introduced to the catalyst bed reactor 10 along with the hexane stream (hydrocarbon feed 4), the temperature of the solid acid catalyst bed 14 is less disrupted as less external input from the controller heating the wall of the catalyst bed reactor 10 is required because of the heat generating material and its exothermic reaction.

Similarly, with reference to FIG. 3, the thermal neutrality of the hydrocarbon cracking process when the heat generating material stream 2 is added may be seen. Specifically, FIG. 3 demonstrates that when hexane and the heat generating material are provided at a 1:2 ratio the resulting drop in temperature of the solid acid catalyst bed 14 is eliminated. The greater percentage of heat generating material relative to hexane (hydrocarbon) results in the solid acid catalyst bed 14 temperature immediately rising. Conversely, without the heat generating material stream 2, the temperature of the solid acid catalyst bed 14 immediately drops before slowly starting to increase after a period of time.

It is noted that the solid acid catalyst in the solid acid catalyst bed did not exhibit decay after 35 minutes of operation in the illustrative examples.

It should now be understood that the various aspects of the methods of cracking a hydrocarbon feed are described and such aspects may be utilized in conjunction with various other aspects.

In a first aspect, the disclosure provides a method of cracking a hydrocarbon feed. The method comprises introducing a hydrocarbon feed to a cracking reactor, introducing a heat generating material (HGM) stream comprising at least one aldehyde or ketone to the cracking reactor, vaporizing the hydrocarbon feed and the HGM stream, and cracking the hydrocarbon feed to produce a cracking product. The cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons.

In a second aspect, the disclosure provides the method of the first aspect, in which the hydrocarbon feed and HGM stream are vaporized subsequent to introduction to the cracking reactor.

In a third aspect, the disclosure provides the method of the first aspect, in which the hydrocarbon feed and HGM stream are vaporized prior to introduction to the cracking reactor.

In a fourth aspect, the disclosure provides the method of any of the first through third aspects, in which the HGM stream comprises ketone.

In a fifth aspect, the disclosure provides the method of any of the first through fourth aspects, in which the HGM stream comprises an aldehyde.

In a sixth aspect, the disclosure provides the method of the fifth aspect, in which the aldehyde is formaldehyde dissolved in water.

In a seventh aspect, the disclosure provides the method of the sixth aspect, in which the formaldehyde dissolved in water is stabilized with an organic solvent.

In an eighth aspect, the disclosure provides the method of the seventh aspect, in which the organic solvent is methanol.

In a ninth aspect, the disclosure provides the method of any of the first through eighth aspects, in which the HGM stream further comprises an alcohol, an additional ketone, or an additional aldehyde.

In a tenth aspect, the disclosure provides the method of any of the first through ninth aspects, in which the cracking product comprises ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils.

In an eleventh aspect, the disclosure provides the method of any of the first through tenth aspects, in which the cracking reactor is at least one catalyst bed reactor.

In a twelfth aspect, the disclosure provides the method of the eleventh aspect, in which the catalyst bed reactor includes a solid acid catalyst bed disposed in the catalyst bed reactor and the catalyst bed reactor is at a reaction temperature of 250 to 850° C.

In a thirteenth aspect, the disclosure provides the method of the eleventh or twelfth aspects, in which the catalyst bed reactor comprises a fluidized bed reactor, a fixed-bed reactor, a slurry reactor, or a moving bed reactor.

In a fourteenth aspect, the disclosure provides the method of the eleventh or twelfth aspects, in which the catalyst bed reactor is a fixed bed reactor.

In a fifteenth aspect, the disclosure provides the method of any of the twelfth through fourteenth aspects, in which the solid acid catalyst is a ZSM-5 catalyst.

In a sixteenth aspect, the disclosure provides the method of the fifteenth aspect, in which the ZSM-5 catalyst has a Si/Al molar ratio of at least 10.

In a seventeenth aspect, the disclosure provides the method of the fifteenth aspect, in which the ZSM-5 catalyst has a Si/Al molar ratio of at least 30.

In an eighteenth aspect, the disclosure provides the method of the fifteenth aspect, in which the ZSM-5 catalyst comprises phosphorus, boron, nickel, iron, tungsten, or combinations thereof.

In a nineteenth aspect, the disclosure provides the method of any of the first through eighteenth aspects, in which the HGM stream and the hydrocarbon feed stream are fed at a weight ratio of 1:10 to 10:1.

In a twentieth aspect, the disclosure provides the method of any of the first through nineteenth aspects, in which the hydrocarbon feed stream comprises non-fractioned or fractioned crude oil, hexane, naphtha, mixed butenes, ethylene, and combinations thereof.

It should be apparent to those skilled in the art that various modifications and variations can be made to the embodiments described here without departing from the spirit and scope of the claimed subject matter. Thus it is intended that the specification cover the modifications and variations of the various embodiments described here provided such modification and variations come within the scope of the appended claims and their equivalents.

Throughout this disclosure ranges are provided. It is envisioned that each discrete value encompassed by the ranges are also included. Additionally, the ranges which may be formed by each discrete value encompassed by the explicitly disclosed ranges are equally envisioned.

Claims

1. A method of cracking a hydrocarbon feed comprising:

introducing a hydrocarbon feed to a cracking reactor;
introducing a heat generating material (HGM) stream comprising at least one aldehyde or ketone to the cracking reactor;
vaporizing the hydrocarbon feed and the HGM stream; and
cracking the hydrocarbon feed to produce a cracking product, where the cracking product comprises C1-C4 hydrocarbons and C5+ hydrocarbons.

2. The method of claim 1, where the hydrocarbon feed and HGM stream are vaporized subsequent to introduction to the cracking reactor.

3. The method of claim 1, where the hydrocarbon feed and HGM stream are vaporized prior to introduction to the cracking reactor.

4. The method of claim 1, where the HGM stream comprises ketone.

5. The method of claim 1, where the HGM stream comprises an aldehyde.

6. The method of claim 5, where the aldehyde is formaldehyde dissolved in water.

7. The method of claim 6, where the formaldehyde dissolved in water is stabilized with an organic solvent.

8. The method of claim 7, where the organic solvent is methanol.

9. The method of claim 1, where the HGM stream further comprises an alcohol, an additional ketone, or an additional aldehyde.

10. The method of claim 1, where the cracking product comprises ethylene, propylene, butenes, benzene, toluene, xylenes, ethylbenzene, H2, methane, ethane, LPG, naphtha, gasoline, and gas oils.

11. The method of claim 1, where the cracking reactor is at least one catalyst bed reactor.

12. The method of claim 11, where the catalyst bed reactor includes a solid acid catalyst bed disposed in the catalyst bed reactor and the catalyst bed reactor is at a reaction temperature of 250 to 850° C.

13. The method of claim 12, where the catalyst bed reactor comprises a fluidized bed reactor, a fixed-bed reactor, a slurry reactor, or a moving bed reactor.

14. The method of claim 13, where the catalyst bed reactor is a fixed bed reactor.

15. The method of claim 12, where the solid acid catalyst is a ZSM-5 catalyst.

16. The method of claim 15, where the ZSM-5 catalyst has a Si/Al molar ratio of at least 10.

17. The method of claim 15, where the ZSM-5 catalyst has a Si/Al molar ratio of at least 30.

18. The method of claim 15, where the ZSM-5 catalyst comprises phosphorus, boron, nickel, iron, tungsten, or combinations thereof.

19. The method of claim 1, where the HGM stream and the hydrocarbon feed stream are fed at a weight ratio of 1:10 to 10:1.

20. The method of claim 1, where the hydrocarbon feed stream comprises non-fractioned or fractioned crude oil, hexane, naphtha, mixed butenes, ethylene, and combinations thereof.

Patent History
Publication number: 20170327750
Type: Application
Filed: May 2, 2017
Publication Date: Nov 16, 2017
Applicant: Saudi Arabian Oil Company (Dhahran)
Inventors: Hussein Mohammed Al Yami (Thuwal), Miao Sun (Thuwal), Ola Ali (Thuwal), Wei Xu (Thuwal)
Application Number: 15/584,598
Classifications
International Classification: C10G 11/02 (20060101); C10G 11/16 (20060101); C10G 11/05 (20060101); C10G 11/18 (20060101); C10G 11/10 (20060101);