EP3356496B1

EP3356496B1 - A catalytic process for reducing chloride content of a hydrocarbon feed stream

Info

Publication number: EP3356496B1
Application number: EP16774820.1A
Authority: EP
Inventors: Abrar A. HAKEEM; Ashim Kumar Ghosh
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2015-11-13
Filing date: 2016-09-23
Publication date: 2021-12-01
Anticipated expiration: 2036-09-23
Also published as: CN108291156A; WO2017083018A1; US20190062646A1; JP6824981B2; EP3356496A1; JP2018537558A

Description

BACKGROUND OF THE INVENTION

TECHNICAL FIELD

The present invention relates to a process of reducing the chloride content of a hydrocarbon feed stream comprising a chloride containing pyrolysis oil by contacting the hydrocarbon feed stream with a catalyst in the presence of hydrogen gas.

DESCRIPTION OF THE RELATED ART

The "background" description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
Plastic waste may be converted into useful liquids, gas fuels or commodity chemicals using a pyrolysis process. However, plastic waste may contain polyvinylchloride (PVC) which leads to the formation organic chlorides during the pyrolysis process. The organic chlorides may then form HCl in downstream processes, which can cause corrosion of equipment and may also act as a poison for catalysts used in the downstream processes. Therefore, the removal of organic chlorides, and thus HCl, from plastic waste derived feedstocks is important and typically an acceptable concentration of total chloride in many chemical industries for example, hydrogen/ammonia, is less than 1 ppm ( US7501112 B2 ) or even 1 ppb (AIChE Journal, 51 (2005) 2016-2023) depending on the sensitivity towards chloride of catalysts used in the downstream processes. Further, the concentration of organic chlorides in plastic feed pyrolysis products can be high, for example close to 2000 ppmw (Applied Catalysis A: General, 207 (2001) 79-84) or greater than 2,000 ppmw (Fuel Processing Technology, 92 (2011) 253-260), depending on the amount of PVC present in the feedstock or the method used to process the plastic waste. Hereinafter, the concentration of chloride refers to the amount of chloride relative to the total weight of the hydrocarbon feed. Lingaiah et. al (Applied Catalysis A: General, 207 (2001) 79-84) have used Fe₂O₃ to remove organic chloride from the pyrolysis oil at 350°C. Lopez et. al have used (Fuel Processing Technology, 92 (2011) 253-260) CaCO₃ as a scavenger to react with organic chloride formed during the plastic waste pyrolysis.
CN 104 815 681 A describes a hydrodechlorination catalyst comprising, by mass, 18-28% of molybdenum trioxide, 3-10% of phosphorus oxide, 2-8% of nickel oxide, and the balance being aluminum oxide or aluminum oxide and silicon oxide. The preparation method of the hydrodechlorination catalyst comprises: (a) preparation of a catalyst carrier, (b) preparation an active component solution, (c) dipping, (d) drying and (e) roasting. The hydrodechlorination catalyst is applied to removal of organic chlorides in pyrolysis oil generated by waste tire pyrolysis.
In view of the foregoing, an objective of the present invention is to provide a process of reducing the chloride content of a hydrocarbon feed stream comprising a chloride containing pyrolysis oil by contacting the hydrocarbon feed stream with a catalyst in the presence of hydrogen gas.

BRIEF SUMMARY OF THE INVENTION

The present invention relates to a process for reducing a chloride content of a hydrocarbon feed stream involving i) cracking a chloride containing thermoplastic material for obtaining a chloride containing pyrolysis oil; ii) contacting a hydrocarbon feed stream comprising a chloride containing pyrolysis oil with a catalyst on a catalyst support, the catalyst being Cu and Zn on an alumina support, in the presence of hydrogen gas at a temperature of 60-300°C and a pressure of 25-35 bars to reduce one or more organic chloride compounds present in the hydrocarbon feed stream and form a hydrocarbon product stream and HCl; iii) removing the HCl from the hydrocarbon product stream, wherein the chloride containing pyrolysis oil has a boiling point of less than 400°C, wherein the hydrocarbon product stream has a chloride content of greater than 2000 ppmw and less than 5000 ppmw relative to the total weight of the hydrocarbon feed stream; and wherein the molar ratio of the hydrogen gas to the hydrocarbon feed stream is 10:1 to 1:1.5, whereby the hydrocarbon product stream has a chloride content of less than 10 ppmw relative to the total weight of the hydrocarbon feed stream.
In one embodiment, the one or more organic chloride compounds is at least one selected from the group consisting of p-chlorotoluene, chlorobenzene, chlorocyclopentane, 1-chlorooctane, and 2-chloro-2-methylbutane.
In one embodiment, the catalyst is present in a catalyst chamber within a reactor vessel, and the contacting includes feeding the hydrocarbon feed stream into the catalyst chamber of the reactor vessel with a weight hourly space velocity of 1-6 h^-1.
In one embodiment, the catalyst Cu and Zn has a largest dimension of 100 µm - 3 mm.
In one embodiment, the chloride containing pyrolysis oil has a low boiling fraction with a boiling point of less than 190°C.
In one embodiment, the removing includes one or more of stripping, washing, and neutralizing the HCl from the hydrocarbon product stream.
In the present invention, the hydrocarbon feed stream has a chloride content of greater than 2000 ppmw and less than 5000 ppmw relative to the total weight of the hydrocarbon feed stream and the hydrocarbon product stream has a chloride content of less than 10 ppmw relative to the total weight of the hydrocarbon product stream.
The foregoing paragraphs have been provided by way of general introduction, and are not intended to limit the scope of the following claims. The described embodiments, together with further advantages, will be best understood by reference to the following detailed description taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

Fig. 1 is an illustration of a process scheme for removing the organic chlorides present in the hydrocarbon feed stream.
Fig. 2 is an illustration of a process scheme for removing the organic chlorides present in the hydrocarbon feed stream.
Fig. 3 is a plot illustrating the conversion of different type of chloride species (total chloride 4,000 ppmw in the hydrocarbon feed stream) over the sulfided NiMo catalyst at WHSV of 2 h^-1 at 300°C, a pressure of 30 barg and a molar ratio of hydrogen gas to hydrocarbon feed stream of 1:1 is used (out of the invention).
Fig. 4 is a plot illustrating the conversion of different type of chloride species (total chloride 4,000 ppmw in the hydrocarbon feed stream) over the sulfided NiMo catalyst at WHSV of 2 h^-1 at 200°C, a pressure of 30 barg, and a molar ratio of hydrogen gas to hydrocarbon feed stream of 1:1 is used (out of the invention).
Fig. 5 is a plot illustrating the conversion of different type of chloride species (total chloride 4,000 ppmw in the hydrocarbon feed stream) over the Pd/Al₂O₃ catalyst at WHSV of 2 h^-1 at 200°C, a pressure of 30 barg, and a molar ratio of hydrogen gas to hydrocarbon feed stream of 1:1 is used (out of the invention).
Fig. 6 is a plot illustrating the conversion of different type of chloride species (total chloride 4,000 ppmw in the hydrocarbon feed stream) over the Cu-ZnO catalyst at WHSV of 2 h^-1 at 200°C, a pressure of 30 barg, and a molar ratio of hydrogen gas to hydrocarbon feed stream of 1:1 is used.
Fig. 7 is a plot illustrating the conversion of different type of chloride species (total chloride 4,000 ppmw in the hydrocarbon feed stream) over an inert SiC at WHSV of 1 h^-1 at 200°C, a pressure of 30 barg, and a molar ratio of hydrogen gas to hydrocarbon feed stream of 1:1 is used.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views.
The present invention relates to a process for reducing a chloride content of a hydrocarbon feed stream comprising a chloride containing pyrolysis oil with a catalyst Cu and Zn on an alumina support, in the presence of hydrogen gas to reduce one or more organic chloride compounds present in the hydrocarbon feed stream and form a hydrocarbon product stream and HCl, wherein the chloride containing pyrolysis oil is obtained by cracking a chloride containing thermoplastic material.
A thermoplastic material is a polymeric material that becomes pliable or moldable above a specific temperature. As used herein, a "thermoplastic material" may refer to virgin plastic materials, scrap plastic materials generated during the processing of plastic materials into desired articles, or plastic materials which remain after an article has performed its intended function. Exemplary polymeric plastic materials include materials comprising polyethylene (PE), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), polychloroprene, nylon, polyvinyl chloride (PVC), polyacrylonitrile (PAN), or polyurethane (PU). A chloride containing thermoplastic material is a particular type of polymeric material that contains chloride, or a polymeric material that has been chlorinated, for example polyvinyl chloride (PVC), chlorinated polyvinyl chloride (CPVC), neoprene, and the like.
A chloride containing pyrolysis oil is a pyrolysis oil product that contains one or more organic chloride compounds obtained by cracking a feedstock containing a chloride containing thermoplastic material. In one embodiment, the organic chloride compounds may include aromatic chloride compounds and aliphatic chloride compounds. Exemplary organic chloride compounds include p-chlorotoluene, chlorobenzene, chlorocyclopentane, 1-chlorooctane, 2-chloro-2-methylbutane, and derivatives and mixtures thereof. The chloride containing pyrolysis oil has a boiling point of less than 400°C, preferably less than 390°C, preferably less than 380°C, preferably less than 370°C, preferably less than 360°C, preferably less than 350°C, preferably less than 340°C, preferably less than 330°C, preferably less than 320°C, preferably less than 310°C, preferably less than 300°C, preferably less than 290°C, preferably less than 280°C, preferably less than 270°C, preferably less than 260°C, preferably less than 250°C, preferably less than 240°C, preferably less than 230°C, preferably less than 220°C, preferably less than 210°C, preferably less than 200°C, preferably less than 190°C. In one embodiment, the chloride containing pyrolysis oil has a low boiling fraction and the low boiling fraction has a boiling point of less than 190°C, less than 189°C, less than 188°C, less than 187°C, less than 186°C, less than 185°C, less than 184°C, less than 183°C, less than 182°C, less than 181°C, less than 180°C. For example, 80°C-190°C, 100°C-180°C, 120°C-175°C, 125°C-170°C.
In addition to the chloride containing pyrolysis oil, the hydrocarbon feed stream of the present disclosure includes one or more hydrocarbon compounds, such as C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆ etc. containing compounds. The hydrocarbon feed stream may contain aliphatic hydrocarbon compounds, including, but not limited to, ethane, propane, butane, isobutane, pentane, hexane, heptane, octane, as well as higher molecular weight aliphatic hydrocarbon compounds nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, and isomers and derivatives (e.g. unsaturated derivatives) thereof. The hydrocarbon feed stream may also contain aromatic hydrocarbon compounds, such as benzene, styrene, xylene, toluene, ethyl benzene, indene, naphthalene, isomers and derivatives thereof, and the like. In one embodiment, the hydrocarbon feed stream comprises at least 100 ppm, at least 200 ppm, at least 500 ppm, at least 1,000 ppm, at least 1,500 ppm, at least 2,000 ppm, at least 2,500 ppm, at least 3,000 ppm, at least 3,500 ppm, at least 4,000 ppm, and no more than 10,000 ppm, no more than 9,000 ppm, no more than 8,000 ppm, no more than 7,000 ppm, no more than 6,000 ppm, no more than 5,000 ppm of the chloride containing pyrolysis oil or alternatively the organic chloride compounds. For example, the hydrocarbon feed stream comprises about 3,500-4,500 ppm of chloride.
A sulfided catalyst, not according to the invention, comprises at least one selected from the group consisting of CoMo, NiMo, and Ni/Al₂O₃. In one embodiment, the sulfided catalyst is CoMo, and the bimetallic CoMo catalyst has a Co:Mo ratio of 10:1 to 1:10, 9:1 to 1:9, 8:1 to 1:8. In one embodiment, the sulfided catalyst is NiMo, and the bimetallic NiMo catalyst has a Ni:Mo ratio of 10:1 to 1:10, 9:1 to 1:9, 8:1 to 1:8. Additional metals based on elements from Group 6, 8, 9, 10, or 11 of the Periodic Table of Elements may also be incorporated into the sulfided catalysts to form bimetallic or multimetallic catalysts. For example, chromium and/or tungsten may also be present in the sulfided catalyst to form, for example a NiMoW catalyst. In one embodiment, the sulfided catalyst is relatively more selective towards the reduction of chloride from organic chloride compounds and relatively less selective for converting olefin-containing compounds into to saturated compounds.
Other catalysts may also be used in the chloride removal process in addition to the sulfided catalysts. Exemplary other catalysts include Pt or Pd-supported on alumina catalysts, and the like.
The sulfided catalysts may be supported on a catalyst support or unsupported catalysts. In the present disclosure a catalyst support refers to a high surface area material to which a catalyst is affixed. The support may be inert or may participate in catalytic reactions. The reactivity of heterogeneous catalysts and nanomaterial-based catalysts occurs at the surface atoms. Consequently great effort is made to maximize the surface area of a catalyst by distributing it over the support. Catalyst supports that may be used include various kinds of carbon, alumina, silica, silica-alumina (including conventional silica-alumina, silica-coated alumina, and alumina-coated silica), titania, zirconia, cationic clays or anionic clays such as saponite, bentonite, kaoline, sepiolite or hydotalcite, and the like. In the present invention, the catalyst support is aluminum oxide (i.e. alumina). The catalyst support may be comprised of a plurality of different crystallographic phases. Therefore, in terms of alumina, the catalyst support may comprise (α-Al₂O₃, γ-Al₂O₃, η-Al₂O₃, θ-Al₂O₃, χ-Al₂O₃, κ-Al₂O₃, and δ-Al₂O₃, or mixtures thereof. If alumina is applied as a support, the surface area preferably may be in the range of 100-400 m²/g, or 150-350 m²/g, measured by the B.E.T. method. The pore volume of the alumina in one embodiment is in the range of 0.5-1.5 ml/g measured by nitrogen adsorption.
In one embodiment, the catalyst support material may have less catalytic activity than the bulk catalyst composition or no catalytic activity at all. Consequently, by adding a catalyst support material, the activity of the bulk catalyst composition may be reduced. Therefore, the amount of catalyst support material present may depend on the desired activity of the final catalyst composition. Catalyst support amounts from 0-99.9 wt% of the total catalyst composition (i.e. the total weight of the catalyst, for example CoMo or Ni, and the catalyst support, for example alumina) can be present, or in the range of more than 5 wt%, 10 wt%, 15 wt%, 20 wt%, 30 wt%, 40 wt% and less than 99 wt%, 95 wt%, 90 wt%, 85 wt%, 80 wt%, 75 wt%. For example, for a CoMo catalyst, the catalyst composition may comprise 10-25 wt% Mo, 2-10 wt% Co, and 50-80 wt% Al₂O₃. For a NiMo catalyst, the catalyst composition may comprise 10-20 wt% Ni, 2-10 wt% Mo, and 50-80% Al₂O₃. For a Ni/Al₂O₃ catalyst, the catalyst composition may include 10-20 wt% Ni and 80-90 wt% Al₂O₃.
In one embodiment, the catalyst support may be composited with the catalytic metal (i.e. Cu and Zn) by any impregnation technique, which is known to those of ordinary skill in the art. In an alternative embodiment, the catalyst used to dechlorinate the hydrocarbon stream may be made by co-precipitating the catalytic metal (i.e. Cu and Zn) with the catalyst support using any co-precipitation method/technique known to those of ordinary skill in the art.
Referring now to Fig. 1 and Fig. 2. In one or more embodiments, the catalyst and any catalyst support present may be housed within a reactor vessel 103 in the form of a catalyst bed, for example a moving, fluidized, or preferably a fixed bed. Therefore, the contacting may involve feeding the hydrocarbon feed stream comprising the chloride containing pyrolysis oil, which is obtained by cracking a chloride containing thermoplastic material, through or over a catalyst bed in a reactor vessel 103 containing the catalyst and optionally a catalyst support, where the feeding is performed in the presence of hydrogen gas 102 to reduce one or more organic chloride compounds present in the hydrocarbon feed stream 101 and form a hydrocarbon product stream 106 and HCl 105. The hydrocarbon feed stream 101 and the hydrogen gas 102 may be mixed prior to entering the reactor vessel 103, or alternatively mixed while inside the reactor vessel 103. When mixed prior to entering the reactor vessel 103, the hydrocarbon feed stream 101 and the hydrogen gas 102 may be mixed by joining their respective feed lines (as depicted in Fig. 1) or through the use of a three-way flow control valve (as depicted in Fig. 2). In one embodiment, the reactor vessel is constructed with materials that are resistant to acidic corrosion, such as corrosion caused by HCl. For example, the reactor vessel may comprise ceramic materials, glass, quartz, and/or alloy materials such as Inconel. In one embodiment, the sulfided catalyst may be uniformly distributed throughout a matrix of catalyst support, where the concentration of the sulfided catalyst differs by no more than 5%, by no more than 4%, by no more than 3%, by no more than 2%, by no more than 1% by weight at any given cross section throughout the catalyst bed. In an alternative embodiment, the sulfided catalyst may be non-uniformly distributed throughout the catalyst support, and may form a gradient across the catalyst bed (i.e. where the concentration at the bottom of the catalyst bed differs by more than 5% from the concentration of the sulfided catalyst at the top of the catalyst bed).
As an example, not covered by the present invention, the catalyst bed may include two or more different sulfided catalysts (e.g. Ni/Al₂O₃ and CoMo catalysts) or at least one sulfided catalyst and at least one additional catalyst type (e.g. CoMo and Pd/Pt catalyst). In one embodiment, two different catalysts are evenly dispersed within a catalyst support. In an alternative embodiment, the catalyst bed comprises a plurality of divided layers, each divided layer comprising a different catalyst or concentration of catalyst, such that a hydrocarbon feed stream being fed through the catalyst bed passes sequentially through each divided layer. The ratio of the two or more different sulfided catalysts (i.e. the ratio of first sulfided catalyst to the second sulfided catalyst), or the ratio of at least one sulfided catalyst to the at least one additional catalyst may range from 10:1 to 1:10, 9:1 to 1:9, 8:1 to 1:8, 7:1 to 1:7, 6:1 to 1:6. In yet another example not according to the present invention, the contacting involves feeding the hydrocarbon feed stream sequentially through a first reactor vessel having a first catalyst (e.g. the sulfided catalyst) then through a second reactor vessel having a second catalyst (e.g. noble metal catalyst). It may be advantageous for the chloride removal process to include more than one type of catalyst, since catalysts have varying selectivity towards various substrates. Therefore, since the chloride containing pyrolysis oil may contain a plurality of organic chloride compounds, a catalyst bed comprising a plurality of various catalysts may be more efficient at removing chloride from the pyrolysis oil. For example, a catalyst bed having CoMo, which efficiently reduces aromatic chlorides, may provide an advantage in removing chloride from a hydrocarbon feed stream having both aromatic and aliphatic chlorides over a catalyst bed having only one type of catalyst.
According to embodiments of the disclosure, the catalyst used to remove chloride is generally comprised of porous metal and/or support components having a suitable pore volume and pore size, such as, for example, a pore volume of 0.05-1 ml/g, or of 0.1-0.94 ml/g, or of 0.1-0.8 ml/g or of 0.1-0.6 ml/g determined by nitrogen adsorption. Pores with a diameter smaller than 1 nm may be but are generally not present. Further, the catalysts may generally have a surface area of at least 10 m²/g, or at least 50 m²/g, or at least 100 m²/g, or at least 150 m²/g or at least 200 m²/g determined via the Brunauer-Emmett-Teller (B.E.T.) method.
The sulfided catalyst may be in the form of any shape, for example, a sphere or substantially spherical (i.e. oblong), a cylinder, a slab or rectangular, an extrudate with a quadralobe cross section, an extrudate with a trilobe cross section, etc. In one embodiment, the sulfided catalyst has a largest dimension of 100 µm to 3 mm, 120 µm to 2.8 mm, 140 µm to 2.6 mm, 160 µm to 2.4 mm, 180 µm to 2.2 mm. In some embodiments, the sulfided catalyst has a largest dimension of about 100-500 µm, preferably 110-490 µm, preferably 120-480 µm, preferably 130-470 µm, preferably 140-460 µm, preferably 150-450 µm, preferably 160-440 µm, preferably 170-430 µm, preferably 180-420 µm, 190-410 µm, preferably 200-405 µm, preferably 212-400 µm, preferably 220-380 µm, preferably 230-370 µm, more preferably 240-360 µm. However, the sulfided catalyst may have different dimensions than those stated above and still function as intended in the process for reducing a chloride content of the hydrocarbon feed stream. In one embodiment, the sulfided catalyst may have a largest dimension of up to 4 mm, up to 3.8 mm, up to 3.6 mm, up to 3.4 mm, up to 3.2 mm, up to 3.0 mm. For example, the sulfided catalyst may be in the form of a sphere (or may be substantially spherical) having a largest diameter of greater than 0.5 mm and less than 4 mm, less than 3.8 mm, less than 3.6 mm, less than 3.4 mm, less than 3.2 mm, less than 3.0 mm, less than 2.8 mm, less than 2.6 mm, less than 2.4 mm, less than 2.2 mm, less than 2.0 mm. In another example, the sulfided catalyst may be an extrudated catalyst in the form of a cylinder (or alternatively a slab) having a largest diameter (or a longest cross sectional dimension in the case of a slab shape) of 2.0-4.0 mm, preferably 2.0-3.8 mm, preferably 2.2-3.6 mm, preferably 2.4-3.4 mm, preferably 2.6-3.2 mm.
In one embodiment, the sulfided catalyst is present in a catalyst chamber within the reactor vessel, and the contacting includes feeding the hydrocarbon feed stream into the catalyst chamber of the reactor vessel with a weight hourly space velocity (WHSV) of 0.5 h^-1 to 6 h^-1, 0.8 h^-1 to 5.5 h^-1, 1 h^-1 to 5 h^-1, 1.5 h^-1 to 4.5 h^-1. In one embodiment, the hydrocarbon feed stream has a residence time in the reactor vessel/catalyst chamber of less than about 1 hour, less than about 40 minutes, less than about 30 minutes, less than about 15 minutes, less than about 10 minutes. Preferably the hydrocarbon feed stream has a residence time in the reactor vessel/catalyst chamber of less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes. For example, from about 1 minute to about 20 minutes. The shortest residence time the hydrocarbon feed stream is present in the reactor vessel will be the time taken for the hydrocarbon feed stream to be transported from the inlet of the reactor vessel to the outlet of the reactor vessel.
In one embodiment, the molar ratio of the hydrogen gas to the hydrocarbon feed stream during the contacting is 10:1 to 1:1.5, preferably 9:1 to 1:1.5, preferably 8:1 to 1:1.5, preferably 7:1 to 1:1.5, preferably 6:1 to 1:1.5, preferably 5:1 to 1:1.5, preferably 4:1 to 1:1.5, preferably 3:1 to 1:1.5, preferably 2:1 to 1:1.5, preferably 1.5:1 to 1:1.5, preferably 1.4:1 to 1:1.4, more preferably 1.3:1 to 1:1.3, more preferably 1.2:1 to 1:1.2, even more preferably 1.1:1 to 1:1.1. While it may be advantageous to use a molar ratio of hydrogen gas to the hydrocarbon feed stream that is about 1:1, the use of a higher ratio (i.e. increased amount of hydrogen), for example up to 10:1, up to 7:1, up to 5:1, up to 3:1 may still be utilized and the process will still proceed as intended. In one or more embodiments, hydrogen gas that exits the reactor vessel after the contacting may be recirculated back into the reactor vessel, after appropriate separation of the hydrogen gas from the hydrocarbon product stream.
In one embodiment, the hydrocarbon feed stream is contacted to the sulfided catalyst at a temperature of 60-400°C, 70-390°C, 80-380°C and a pressure of 25-35, 26-34, 27-33, 28-32, 29-31 barg.
In one embodiment, the sulfided catalyst may be sulfided ex-situ, whereby the catalyst is sulfided with a sulfur containing material. The sulfiding process may take place outside of the reactor vessel, where the catalyst is treated with a sulfur containing material, and then loaded into the catalyst bed of the reactor vessel. Alternatively, the catalyst may be sulfided in-situ by first loading the catalyst into the catalyst chamber where the contacting is to take place, then treating the loaded catalyst with the sulfur containing material. This sulfiding process may be performed to increase the catalytic activity of the catalyst or to attenuate the catalytic properties of the catalyst (e.g. change the selectivity properties or the activity of the catalyst).
In one embodiment, the hydrocarbon feed stream further comprises up to 200 ppmw, preferably up to 190 ppmw, preferably up to 180 ppmw, preferably up to 170 ppmw, preferably up to 160 ppmw, preferably up to 150 ppmw, preferably up to 140 ppmw, preferably up to 130 ppmw, preferably up to 120 ppmw, preferably up to 100 ppmw, preferably up to 90 ppmw, preferably up to 80 ppmw, preferably up to 70 ppmw, preferably up to 60 ppmw, preferably up to 50 ppmw, preferably up to 40 ppmw, preferably up to 30 ppmw of a sulfur containing material relative to the total weight of the hydrocarbon feed stream. In one embodiment, the catalyst is sulfided during the contacting with the sulfur containing material present in the hydrocarbon feed stream so as to maintain the catalyst in a sulfided form. In this scenario, the catalyst prior to the contacting with the hydrocarbon feed stream may be in a non-sulfided form, or may be sulfided, and the sulfur containing material present in the hydrocarbon feed stream and/or the chloride containing pyrolysis oil maintains the catalyst in a sulfided form throughout the chloride removal process.
The process, not according to the invention, further comprises contacting a sulfur stream comprising no more than 8 wt%, no more than 7 wt%, no more than 6 wt%, no more than 5 wt%, no more than 4 wt%, no more than 3 wt%, no more than 2 wt%, no more than 1 wt% of a sulfur containing material relative to the total weight of the sulfur stream with a catalyst comprising at least one of Co, Mo, and Ni to form the sulfided catalyst prior to the contacting of the hydrocarbon feed stream (i.e. a sulfiding process to form the sulfided catalyst). The sulfur containing material that can be used to sulfide the catalyst prior to the contacting, to sulfide the catalyst during the contacting, or to maintain the sulfided catalyst in a sulfided form during the contacting includes H₂S, carbon disulfide, dimethyl disulfide, ethyl disulfide, propyl disulfide, isopropyl disulfide, butyl disulfide, tertiary butyl disulfide, thianaphthene, thiophene, secondary dibutyl disulfide, thiols, sulfur containing hydrocarbon oils and sulfides such as methyl sulfide, ethyl sulfide, propyl sulfide, isopropyl sulfide, butyl sulfide, secondary dibutyl sulfide, tertiary butyl sulfide, dithiols, sulfur-bearing gas oils, and the like. Any other organic sulfur source that can be converted to H₂S over the catalyst in the presence of hydrogen can be used. The catalyst may also be activated by an organo sulfur process as described in US 4,530,917 and other processes described therein and this description is incorporated by reference into this specification. In a preferred embodiment, the sulfur containing material is dimethyl disulfide. In addition to the sulfur containing material, the sulfur stream of the present disclosure may include one or more hydrocarbon compounds, such as C₂, C₃, C₄, C₅, C₆, C₇, C₈, C₉, C₁₀, C₁₁, C₁₂, C₁₃, C₁₄, C₁₅, C₁₆, etc., aliphatic hydrocarbon compounds, including, but not limited to, ethane, propane, butane, isobutane, pentane, hexane, heptane, octane, as well as higher molecular weight aliphatic hydrocarbon compounds nonane, decane, undecane, dodecane, tridecane, tetradecane, pentadecane, hexadecane, and isomers and derivatives (e.g. unsaturated derivatives) thereof, and/or aromatic hydrocarbon compounds, such as benzene, styrene, xylene, toluene, ethyl benzene, indene, naphthalene, isomers and derivatives thereof, and the like. The sulfiding process may involve heating the CoMo, NiMo, and/or Ni/Al₂O₃ catalyst in an inert atmosphere up to 180°C, 190°C, or up to 200°C, reducing the catalysts with H₂ at this elevated temperature, then contacting the sulfur stream to the reduced catalyst at a temperature up to 320°C, up to 340°C, or up to 350°C.
The process also involves removing the HCl from the hydrocarbon product stream. In one embodiment, the removing includes one or more of stripping, washing, and neutralizing the HCl from the hydrocarbon product stream. In one embodiment, the process involves stripping the HCl away from the hydrocarbon product stream, for example through distillation. In one embodiment, the process involves washing and/or neutralizing the HCl from the hydrocarbon product stream or from an off-gas stripped from the hydrocarbon product stream. For example, washing may involve trapping the generated HCl in water to form an acidic aqueous solution. This product may be a saturated HCl solution (36 wt% HCl). In one embodiment, the HCl contains trace amounts of hydrocarbons, which is known to those of ordinary skill in the art as co-product HCl. The neutralizing may involve, for example, contacting the hydrocarbon product stream or the HCl that has been stripped from the hydrocarbon product stream with a neutralizing agent in solid, liquid, or solution form (e.g. amines, hydroxide, carbonates, etc.). Removing the HCl 105 from the hydrocarbon product stream 106 may be performed using a separator 104 (Fig. 1 and Fig. 2). The separator may be a distillation apparatus, a neutralization chamber, a scrubbing chamber, and the like.
In one embodiment, and as can be seen in Fig. 3 and Fig. 4 in terms of conversion, the hydrocarbon product stream has a lower chloride content than the hydrocarbon feed stream, based on the total weight of the chloride and the total weight of the hydrocarbon feed stream. In one embodiment, the hydrocarbon feed stream has a chloride content of greater than 2,000, greater than 2,500, greater than 3,000, greater than 3,500, or greater than 4,000 ppmw, and less than 5,000, less than 4,800, less than 4,600, or less than 4,400 ppmw, relative to the total weight of the hydrocarbon feed stream. In one embodiment, the hydrocarbon product stream has a chloride content of less than 100 ppmw, less than 80 ppmw, less than 60 ppmw, less than 40 ppmw, less than 20 ppmw, less than 15 ppmw, less than 10 ppmw, less than 5 ppmw, or less than 1 ppmw relative to the total weight of the hydrocarbon product stream. Therefore, the process may remove up to 90%, up to 91%, up to 92%, up to 93%, up to 94%, up to 95%, up to 96%, up to 97%, up to 98%, up to 99%, up to 99.5%, up to 99.9% of the chloride content in the hydrocarbon feed stream.
The present invention relates to a process for reducing a chloride content of a hydrocarbon feed stream involving contacting a hydrocarbon feed stream comprising a chloride containing pyrolysis oil with a catalyst Cu and Zn on an Al₂O₃ catalyst support in the presence of hydrogen gas to reduce one or more organic chloride compounds present in the hydrocarbon feed stream and form a hydrocarbon product stream and HCl, wherein the chloride containing pyrolysis oil is obtained by cracking a chloride containing thermoplastic material. The process also involves removing the HCl from the hydrocarbon product stream as described according to the first aspect.
The total catalyst composition (the Cu and Zn and the Al₂O₃ catalyst support) may contain 0.5-99.5%, preferably 20-99%, preferably 40-98%, preferably 60-97%, preferably 80-96%, more preferably 90-95% catalyst support by weight relative to the total weight of the catalyst composition. The total catalyst composition (the Cu and Zn and the Al₂O₃ catalyst support) may contain 0.5-5%, 0.7-4%, 0.8-3%, 0.9-2% catalytic metal (i.e. Cu and Zn) by weight relative to the total weight of the catalyst composition. Additional metals based on elements from Group 6, 8, 9, 10, or 11 of the Periodic Table of Elements may also be incorporated into the catalyst to form bimetallic or multimetallic catalysts. In one embodiment, the catalysts Cu and Zn are relatively more selective towards the reduction of chloride from organic chloride compounds and relatively less selective for converting olefin-containing compounds into to saturated compounds. Unlike the sulfided catalysts described herein, the catalysts Cu and Zn are substantially free of sulfur.
For a Cu/Zn/Al₂O₃ catalyst, the catalyst composition may include 30-70 wt% Cu, 20-50 wt% Zn, and 5-50 wt% Al₂O₃.
In addition to the catalyst Cu and Zn, other catalysts may also be used in the chloride removal process. In this disclosure, SiC, an inert material, was used as blank run or as a comparative example.
In one embodiment, the catalyst Cu and Zn is present in a catalyst chamber within a reactor vessel, and the contacting includes feeding the hydrocarbon feed stream into the catalyst chamber of the reactor vessel with a weight hourly space velocity of 1-6 h^-1, 1-5.5 h^-1, 1-5 h^-1. In one embodiment, the hydrocarbon feed stream has a residence time in the reactor vessel/catalyst chamber of less than about 1 hour, less than about 40 minutes, less than about 30 minutes, less than about 15 minutes, less than about 10 minutes. Preferably the hydrocarbon feed stream has a residence time in the reactor vessel/catalyst chamber of less than 20 minutes, less than 15 minutes, less than 10 minutes, less than 5 minutes. For example, from about 1 minute to about 20 minutes. The shortest residence time the hydrocarbon feed stream is present in the reactor vessel will be the time taken for the hydrocarbon feed stream to be transported from the inlet of the reactor vessel to the outlet of the reactor vessel.
In one embodiment, the catalyst (i.e. the catalytic metal) may be uniformly distributed throughout a matrix of catalyst support, where the concentration of the Cu and Zn catalyst differs by no more than 5%, by no more than 4%, by no more than 3%, by no more than 2%, by no more than 1% by weight at any given cross section throughout the catalyst bed. In an alternative embodiment, the catalyst (i.e. the catalytic metal) may be non-uniformly distributed throughout the catalyst support, and may form a gradient across the catalyst bed (i.e. where the concentration at the bottom of the catalyst bed differs by more than 5% from the concentration of the catalyst at the top of the catalyst bed).
In one embodiment, more than one catalyst may be used in the present process. As an example the catalyst bed may include two or more different catalysts or at least one catalyst Cu and Zn and at least one additional catalyst type (e.g. Pd on Al₂O₃ and Ni/Mo). In one embodiment, two catalysts are evenly dispersed within a catalyst support. In an alternative embodiment, the catalyst bed comprises a plurality of divided layers, each divided layer comprising a different catalyst or concentration of catalyst, such that a hydrocarbon feed stream being fed through the catalyst bed passes sequentially through each divided layer. The ratio of the two or more different catalysts (i.e. the ratio of first catalyst to the second catalyst), or the ratio of at least one catalyst to the at least one additional catalyst may range from 10:1 to 1:10, 9:1 to 1:9, 8:1 to 1:8, 7:1 to 1:7, 6:1 to 1:6. In yet another embodiment, the contacting involves feeding the hydrocarbon feed stream through a reactor vessel having a catalyst (e.g. the Cu and Zn catalyst) then through a second reactor vessel having a second catalyst. It may be advantageous for the chloride removal process to include more than one type of catalyst, since catalysts have varying selectivity towards various substrates. Therefore, since the chloride containing pyrolysis oil may contain a plurality of organic chloride compounds, a catalyst bed comprising a plurality of various catalysts may be more efficient at removing chloride from the pyrolysis oil, since each catalyst may be more reactive towards different organic chloride compounds.
The catalyst Cu and Zn may be in the form of any shape, for example, a sphere or substantially spherical (i.e. oblong), a cylinder, a slab or rectangular, an extrudate with a quadralobe cross section, an extrudate with a trilobe cross section, etc. In one embodiment, the catalyst Cu and Zn has a largest dimension of 100 µm to 3 mm, 120 µm to 2.8 mm, 140 µm to 2.6 mm, 160 µm to 2.4 mm, 180 µm to 2.2 mm. In some embodiments, the catalyst Cu and Zn has a largest dimension of 100-500 µm, preferably 110-490 µm, preferably 120-480 µm, preferably 130-470 µm, preferably 140-460 µm, preferably 150-450 µm, preferably 160-440 µm, preferably 170-430 µm, preferably 180-420 µm, 190-410 µm, preferably 200-405 µm, preferably 212-400 µm, preferably 220-380 µm, preferably 230-370 µm, more preferably 240-360 µm. However, the catalyst Cu and Zn may have different dimensions than those stated above and still function as intended in the process for reducing a chloride content of the hydrocarbon feed stream. In one embodiment, the catalyst Cu and Zn may have a largest dimension of up to 4 mm, up to 3.8 mm, up to 3.6 mm, up to 3.4 mm, up to 3.2 mm, up to 3.0 mm. For example, the catalyst may be in the form of a sphere (or may be substantially spherical) having a largest diameter of greater than 0.5 mm and less than 4 mm, less than 3.8 mm, less than 3.6 mm, less than 3.4 mm, less than 3.2 mm, less than 3.0 mm, less than 2.8 mm, less than 2.6 mm, less than 2.4 mm, less than 2.2 mm, less than 2.0 mm. In another example, the catalyst may be an extrudated catalyst in the form of a cylinder (or alternatively a slab) having a largest diameter (or a longest cross sectional dimension in the case of a slab shape) of 2.0-4.0 mm, preferably 2.0-3.8 mm, preferably 2.2-3.6 mm, preferably 2.4-3.4 mm, preferably 2.6-3.2 mm.
The catalyst Cu and Zn may be activated prior to the contacting by reducing the catalyst in the presence of H₂ and heating to a temperature of up to 400°C, up to 380°C, up to 350°C or up to 300°C.
The hydrocarbon feed stream is contacted to the catalyst Cu and Zn at a temperature of 60-300°C, preferably 70-290°C, more preferably 80-280°C and a pressure of 25-35, 26-34, 27-33, 28-32, 29-31 bars. The hydrocarbon feed stream may be fed into the catalyst bed at a feed rate ranging WHSV from 0.5 h^-1 to 6 h^-1, 0.8 h^-1 to 5.5 h^-1, 1 h^-1 to 5 h^-1, 1.5 h^-1 to 4.5 h^-1.
In one embodiment, and as can be seen in Fig. 6 in terms of conversion, the hydrocarbon product stream has a lower chloride content than the hydrocarbon feed stream, based on the total weight of the chloride and the total weight of the hydrocarbon feed stream. The hydrocarbon feed stream has a chloride content of greater than 2,000, greater than 2,500, greater than 3,000, greater than 3,500, greater than 4,000 ppmw relative to the total weight of the hydrocarbon feed stream and the hydrocarbon product stream has a chloride content of less than 100 ppmw, less than 80 ppmw, less than 60 ppmw, less than 40 ppmw, less than 20 ppmw, less than 15 ppmw, less than 10 ppmw, less than 5 ppmw, less than 1 ppmw relative to the total weight of the hydrocarbon product stream. Therefore, the process may remove up to 90%, up to 91%, up to 92%, up to 93%, up to 94%, up to 95%, up to 96%, up to 97%, up to 98%, up to 99%, up to 99.5%, up to 99.99%, up to 99.999% of the chloride content in the hydrocarbon feed stream.
The examples below are intended to further illustrate protocols for preparing, characterizing and using the catalysts in the process for reducing the chloride content of the hydrocarbon feed stream and are not intended to limit the scope of the claims.

EXAMPLES

Hydrodechlorination experiments were carried out using hydrogenation catalysts as described in Table 1.

Table 1

CoMo catalyst:	MoO₃ (10-25 wt%), Co₂O₃ (2-10 wt%) and Al₂O₃ (50-80 wt%)
NiMo catalyst:	NiO (10-20 wt%), MoO₃ (2-10 wt%) and Al₂O₃ (50-80 wt%)
Ni/Al₂O₃ catalyst:	NiO (10-20 wt%) and Al₂O₃ (80-90 wt%)
Pt/Al₂O₃ catalyst:	Pt (0.2-1.0 wt%) on Al₂O₃ (99 wt%)
Pd/Al₂O₃ catalyst:	Pd (0.1-0.5 wt%) on Al₂O₃ (99.5 wt%)
Cu/Zn/Al₂O₃ catalyst:	CuO (30-70 wt%), ZnO (20-50 wt%) and Al₂O₃ (5-50 wt.%)

The liquid hydrocarbon feed was made by mixing different chloride containing compounds in n-hexadecane (H6703 Sigma-Aldrich, 99% purity) as solvent. The chloride containing compounds were: 0.29 wt% p-chlorotoluene (Sigma Aldrich-111929, 98% purity), 0.25 wt% chlorobenzene (Sigma Aldrich-319996, 99.5% purity), 0.24 wt% chlorocyclopentane (Sigma Aldrich-155136, 99% purity), 0.34 wt% 1-chlorooctane (Sigma Aldrich-125156, 99% purity) and 0.24 wt% 2-chloro-2-methylbutane (Sigma Aldrich-277029, 98% purity) based on the total feed including the solvent. The feed contained around 4000 ppmw of chloride (organic chloride) relative to total weight of the feed including the n-hexadecane solvent.
The hydrodechlorination experiments were carried out in continuous flow fixed bed type reactors. The inside diameter of each reactor vessel was 5 mm. The experiments were carried at a pressure of 30 barg, in the temperature range 60-400°C, hydrogen to hydrocarbon molar ratio of 1 and WHSV of 1-6 h^-1. SiC and Al₂O₃ were also tested in parallel during each experimental run in the reactor vessel. SiC was used to investigate the homogeneous elimination reaction of aliphatic chlorides at high temperatures. Al₂O₃ was used to study the de-chlorination performance without any metal functionality, as all of the catalysts included an alumina support. In the case of catalysts CoMo, NiMo and Ni/Al₂O₃ the catalysts were sulfided using dimethyl disulfide (DMDS) in hexadecane. The DMDS solution in hexadecane consisted of 3wt. % S. The activation procedure of CoMo, NiMo and Ni/Al₂O₃ included heating in N₂ up to 180°C, followed by reduction in H₂ at 180°C for 1 h and spiked sulfur (DMDS) containing hexadecane at 120°C and heating in this mixture up to 345°C. In case of Pt/Al₂O₃, Pd/Al₂O₃ and Cu/ZnO catalysts, the activation was done by reducing the catalysts in-situ using hydrogen and heating to 400 °C at 5°C/min.
All catalysts including inerts were used in the size fraction 212-400 µm. The analysis of product stream (gas and liquid phase) was performed using online GC-FID (gas phase) and offline GC-FID (liquid phase).

EXAMPLE 1 (out of the invention)

Referring to Fig. 3:

Catalyst loading: 0.6426 g NiMo catalyst
Catalyst pretreatment - Sulfided (Sulfided using 3 wt. % S (DMDS) in hexadecane up to 345°C after reduction with hydrogen up to 180°C.
Feed (as described above) 4000 ppmw Cl and 3 wt. S in the form of DMDS
Feed rate 1.27 g/h
H₂/HC ratio equals 1 (all the hydrocarbon feed including chloride species)
Temperature = 300°C, Reactor Inlet Pressure = 30 barg.

As can be seen from Fig. 3, all of the different types of chlorinated species are converted at a temperature of 300°C using the NiMo catalyst.

EXAMPLE 2 (out of the invention)

Referring to Fig. 4:

Catalyst loading: 0.6426 g NiMo catalyst
Catalyst pretreatment - Sulfided (Sulfided using 3 wt. % S (DMDS) in hexadecane up to 345°C after reduction with hydrogen up to 180°C.
Feed (as described above) 4000 ppmw Cl and 3 wt. S in the form of DMDS
Feed rate 1.27 g/h
H₂/HC molar ratio = 1 (including n-hexadecane and chloride species)
Temperature =200°C, Reactor Inlet Pressure = 30 barg.

As can be seen from Fig. 4, all of the aliphatic chlorinated species are converted at a temperature of 200°C using the NiMo catalyst, while the aromatic chloride species are not.

EXAMPLE 3 (out of the invention)

Referring to Fig. 5:

Catalyst loading: 0.6417 g Pd catalyst
Catalyst pretreatment - Catalyst reduced in hydrogen at 400°C
Feed (as described above) 4000 ppmw Cl
Feed rate = 1.28 g/h
H₂/HC molar ratio = 1 (including n-hexadecane and chloride species)
Temperature = 200°C, Reactor Inlet Pressure = 30 barg.

As can be seen from Fig. 5, all of the different types of chlorinated species are converted at a temperature of 200°C using the Pd/Al₂O₃ catalyst. This result is advantageous in that all aromatic chloride species are also converted at low temperature (200°C).

EXAMPLE 4

Referring to Fig. 6:

Catalyst loading: 0.6417 g Cu-Zn catalyst
Catalyst pretreatment - Catalyst reduced in hydrogen at 400°C
Feed (as described above) 4000 ppmw Cl
Feed rate = 1.28 g/h
H₂/HC molar ratio = 1 (including n-hexadecane and chloride species)
Temperature = 200°C, Reactor Inlet Pressure = 30 barg.

As can be seen from Fig. 6, all of the aliphatic chlorinated species are converted at a temperature of 200°C using the Cu-Zn catalyst, while the aromatic chlorides are not completely converted at 200°C.

COMPARATIVE EXAMPLE 5

Referring to Fig. 7:

Catalyst loading: 1.283 g SiC (inert)
Catalyst pretreatment ― SiC heated in hydrogen at 400°C
Feed (as described above): 4000 ppmw Cl
Feed rate = 1.28 g/h
H₂/HC molar ratio = 1 (including n-hexadecane and chloride species)
Temperature =200°C, Reactor Inlet Pressure = 30 barg.

To estimate non-catalytic dechlorination due to elimination reactions, an inert (SiC) was used. The conversions obtained due to elimination reactions are illustrated in Fig. 7. The secondary and tertiary chloride species show conversion, which may be due to elimination, at a temperature of 200°C using the SiC.

Claims

A process for reducing a chloride content of a hydrocarbon feed stream, comprising:
cracking a chloride containing thermoplastic material for obtaining a chloride containing pyrolysis oil;

contacting a hydrocarbon feed stream comprising a chloride containing pyrolysis oil with a catalyst on a catalyst support, the catalyst being Cu and Zn on an alumina support, in the presence of hydrogen gas at a temperature of 60-300°C and a pressure of 25-35 bars to reduce one or more organic chloride compounds present in the hydrocarbon feed stream and form a hydrocarbon product stream and HCl;

removing the HCl from the hydrocarbon product stream;

wherein the chloride containing pyrolysis oil has a boiling point of less than 400°C; wherein the hydrocarbon feed stream has a chloride content of greater than 2000 ppmw and less than 5000 ppmw relative to the total weight of the hydrocarbon feed stream; and

wherein the molar ratio of the hydrogen gas to the hydrocarbon feed stream is 10:1 to 1:1.5,

whereby the hydrocarbon product stream has a chloride content of less than 10 ppmw relative to the total weight of the hydrocarbon product stream.
The process of claim 1, wherein the organic chloride compound is at least one selected from the group consisting of p-chlorotoluene, chlorobenzene, chlorocyclopentane, 1-chlorooctane, and 2-chloro-2-methylbutane.
The process of claim 1, wherein
the Cu/Zn/Al₂O₃ catalyst includes 30-70 wt% Cu, 20-50 wt% Zn, and 5-50 wt% Al₂O₃.
The process of claim 1, wherein the catalyst is present in a catalyst chamber within a reactor vessel, and the contacting includes feeding the hydrocarbon feed stream into the catalyst chamber of the reactor vessel with a weight hourly space velocity of 1-6 h^-1.
The process of claim 1, wherein the catalyst has a largest dimension of 100 µm - 3 mm.
The process of claim 1, wherein the chloride containing pyrolysis oil has a low boiling fraction with a boiling point of less than 190°C.
The process of claim 1, wherein the removing includes one or more of stripping, washing, and neutralizing the HCl from the hydrocarbon product stream.