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US-12623982-B2 - Process for dehydration of normal paraffins to olefins

US12623982B2US 12623982 B2US12623982 B2US 12623982B2US-12623982-B2

Abstract

Processes for dehydrogenating normal paraffins derived from natural oils to olefins are described. The feed stream is passed through an adsorption bed comprising alkaline or alkaline earth cation exchange X-Zeolite to removes essentially all oxygenates and aromatics from the feed stream. One or more additional adsorbent beds having different adsorbents can also be included to remove additional oxygenates and aromatics as well as sulfur compounds, nitrogen compounds, phosphorous compounds, or combinations thereof. The dehydrogenation process can be part of a process for producing alkylbenzenes from natural oils.

Inventors

  • Evgeny T. Kolev
  • Phuong T.M. Do

Assignees

  • UOP LLC

Dates

Publication Date
20260512
Application Date
20231102

Claims (17)

  1. 1 . A method for dehydrogenation of normal paraffins to olefins comprising: deoxygenating a natural oil to form a feed stream comprising C9 to C28 paraffins; linear selective cracking the feed stream in a linear selective cracking unit under linear selective cracking conditions in the presence of a linear selective cracking catalyst to form a first stream comprising normal or lightly branched C9 to C14 paraffins and a second stream comprising isoparaffins; passing said first stream through a first adsorbent bed containing a first adsorbent comprising alkaline or alkaline earth cation exchange X-Zeolite wherein the adsorbent removes at least a portion of the oxygenates and aromatics from the first stream by adsorption to form a treated stream; and dehydrogenating the treated stream to convert at least a portion of the treated stream to olefins and provide a dehydrogenated stream comprising mono-olefins, di-olefins, and aromatics.
  2. 2 . The method of claim 1 further comprising: regenerating the adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the adsorbent.
  3. 3 . The method of claim 1 further comprising; passing the treated stream though a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygenates and aromatics to form a second treated stream.
  4. 4 . The method of claim 3 further comprising: regenerating the second adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the second adsorbent.
  5. 5 . The method of claim 1 further comprising: removing contaminants from the treated stream in a third adsorbent bed comprising a third adsorbent to form a decontaminated stream wherein the contaminates comprise sulfur compounds, or nitrogen compounds, or phosphorous compounds, or combinations thereof, wherein the third adsorbent comprises 13X zeolite, 5A zeolite, an alumina-zeolite, or combinations thereof before dehydrogenating the treated stream.
  6. 6 . The method of claim 1 further comprising: selectively hydrogenating the di-olefins in the dehydrogenated stream to form additional mono-olefins, and separating and removing the aromatics from the mono-olefins to form an aromatics stream comprising the aromatics and a mono-olefins stream comprising the mono-olefins: alkylating benzene with the mono-olefins under alkylation conditions to provide an alkylation effluent comprising alkylbenzenes and benzene; and isolating the alkylbenzenes to provide the alkylbenzene product derived from the natural oil.
  7. 7 . The method of claim 1 wherein the treated stream comprises no more than 6000 ppm of the aromatics and no more than 100 ppm of the oxygenates.
  8. 8 . A method for dehydrogenation of normal paraffins to olefins comprising: deoxygenating a natural oil to form a feed stream comprising C9 to C28 paraffins, linear selective cracking the feed stream in a linear selective cracking unit under linear selective cracking conditions in the presence of a linear selective cracking catalyst to form a first stream comprising normal or lightly branched C9 to C14 paraffins and a second stream comprising isoparaffins; passing said first stream through an adsorbent bed containing an adsorbent comprising alkaline or alkaline earth cation exchange X-Zeolite wherein the adsorbent removes at least a portion of the oxygenates and the aromatics from the first stream by adsorption to form a treated stream; removing contaminants from the treated stream in a third adsorbent bed comprising a third adsorbent to form a decontaminated stream wherein the contaminates comprise sulfur compounds, or nitrogen compounds, or phosphorous compounds, or combinations thereof, wherein the adsorbent comprises 13X zeolite, 5A zeolite, an alumina-zeolite, or combinations thereof; and dehydrogenating the decontaminated stream to convert at least a portion of the decontaminated stream to olefins and provide a dehydrogenated stream comprising mono-olefins, di-olefins, and aromatics; and regenerating the adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the adsorbent.
  9. 9 . The method of claim 8 further comprising; passing the treated stream though a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygenates and aromatics to form a second treated stream before removing the contaminants in the third adsorbent bed.
  10. 10 . The method of claim 8 further comprising: regenerating the second adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the second adsorbent.
  11. 11 . The method of claim 8 further comprising: selectively hydrogenating the di-olefins in the dehydrogenated stream to form additional mono-olefins, and separating and removing the aromatics from the mono-olefins to form an aromatics stream comprising the aromatics and a mono-olefins stream comprising the mono-olefins: alkylating benzene with the mono-olefins under alkylation conditions to provide an alkylation effluent comprising alkylbenzenes and benzene; and isolating the alkylbenzenes to provide the alkylbenzene product derived from the natural oil.
  12. 12 . The method of claim 8 wherein the treated stream comprises no more than 6000 ppm of the aromatics and no more than 100 ppm of the oxygenates.
  13. 13 . A method for dehydrogenation of normal paraffins to olefins comprising: deoxygenating a natural oil to form a first stream comprising C9 to C28 paraffins; linear selective cracking the first stream in a linear selective cracking unit under linear selective cracking conditions in the presence of a linear selective cracking catalyst to form a first stream comprising normal or lightly branched C9 to C14 paraffins and a second stream comprising isoparaffins; passing the first stream comprising normal paraffins, iso paraffins, olefins, oxygenates, and up to 10 wt. % aromatics, through a first adsorbent bed containing a first adsorbent comprising alkaline or alkaline earth cation exchange X-Zeolite wherein the adsorbent removes at least a portion of the oxygenates and the aromatics from the first stream by adsorption to form a treated stream; removing contaminants from the treated stream in a third adsorbent bed before dehydrogenating the treated stream, the third adsorbent bed comprising a third adsorbent to form a decontaminated stream wherein the contaminants comprise sulfur compounds, or nitrogen compounds, or phosphorous compounds, or combinations thereof, wherein the third adsorbent comprises 13X zeolite, 5A zeolite, an alumina-zeolite, or combinations thereof; dehydrogenating the decontaminated stream to convert at least a portion of the decontaminated stream to olefins and provide a dehydrogenated stream comprising mono-olefins, di-olefins, and aromatics; selectively hydrogenating the di-olefins in the dehydrogenated stream to form additional mono-olefins, and separating and removing the aromatics from the mono-olefins to form an aromatics stream comprising the aromatics and a mono-olefins stream comprising the mono-olefins; alkylating benzene with the mono-olefins under alkylation conditions to provide an alkylation effluent comprising alkylbenzenes and benzene; and isolating the alkylbenzenes to provide the alkylbenzene product derived from the natural oil.
  14. 14 . The method of claim 13 further comprising; regenerating the first adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the first adsorbent.
  15. 15 . The method of claim 13 further comprising; passing the treated stream though a second adsorbent bed containing a second adsorbent comprising 5A zeolite to remove additional oxygenates and aromatics to form a second treated stream.
  16. 16 . The method of claim 15 further comprising; regenerating the second adsorbent bed at a predetermined time to remove at least a portion of the oxygenates, or aromatics, or both adsorbed onto the second adsorbent.
  17. 17 . The method of claim 13 wherein the treated stream comprises no more than 6000 ppm of the aromatics and no more than 100 ppm of the oxygenates.

Description

RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application Ser. No. 63/504,884, filed on May 30, 2023, the entirety of which is incorporated herein by reference. BACKGROUND Linear alkylbenzenes are organic compounds with the formula C6H5CnH2n+1. While the alkyl carbon number, “n” can have any practical value, detergent manufacturers desire that alkylbenzenes have alkyl carbon number in the range of 9 to 16 and preferably in the range of 9 to 14. These specific ranges are often required when the alkylbenzenes are used as intermediates in the production of surfactants for detergents. The alkyl carbon number in the range of 9 to 14 falls in line with the specifications of the detergents industry. Because the surfactants created from alkylbenzenes are biodegradable, the production of alkylbenzenes has grown rapidly since their initial uses in detergent production in the 1960s. The linearity of the paraffin chain in the alkylbenzenes is key to the material's biodegradability and effectiveness as a detergent. A major factor in the final linearity of the alkylbenzenes is the linearity of the paraffin component. While detergents made utilizing alkylbenzene-based surfactants are biodegradable, previous processes for creating alkylbenzenes are not based on renewable sources. Specifically, alkylbenzenes are currently produced from kerosene refined from crude extracted from the earth. Due to the growing environmental prejudice against fossil fuel extraction and economic concerns over exhausting fossil fuel deposits, there may be support for using an alternate source for biodegradable surfactants in detergents and in other industries. The C9 to C14 paraffins generated from feedstocks based on vegetable oils or animal fats contain contaminants that can poison dehydrogenation catalysts. The contaminants can also cause discoloration of the linear alkylbenzenes and linear alkylbenzene sulfonates. The contaminants can include aromatics, light oxygenates, fatty acids, fatty esters, and the like. These contaminants need to be removed before the C9 to C14 paraffins are dehydrogenated. Accordingly, it is desirable to provide decontaminated C9 to C14 paraffins from renewable easily processed triglycerides and fatty acids from vegetable, animal, nut, and/or seed oils to the dehydrogenation unit. Palm kernel oil, coconut oil and babassu oil have a composition that is high in the desirable range of C9-C14 n-paraffins that aligns with the alkyl carbon number range desired of the detergent industry. Such renewable sources also have a high amount of nC16 to nC18 feeds, and it is desirable to convert those feeds to nC9 to nC14 feeds with a high per-pass yield. These nC9 to nC14 intermediate products are useful in eventually making linear alkylbenzene types of detergents through additional process steps. It is further desirable that the resulting nC9 to nC14 paraffins are linear products with a minimum of branched isomer products. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of one embodiment of a process for producing alkylbenzenes from triglycerides according to the present invention. FIG. 2 is a plot of the mass-% normal paraffins versus deoxygenation temperature in accordance with Example 2. DETAILED DESCRIPTION The present invention relates to a process for dehydrogenation of normal paraffins to olefins. The paraffins come from renewable feedstocks comprising natural oils, such as vegetable oils, animal fats, nut, and/or seed oils, and triglyceride-containing oils. The purification process for the renewable bio-paraffin stream involves passing the stream through one or more adsorbent beds comprising adsorbents. Natural oils are not based on kerosene or other fossil fuels. Natural oils include those derived from plant or algal material or animal fats, nut, and/or seed oils, and triglyceride-containing oils, and are often referred to as renewable oils. Natural oils typically comprise triglycerides, free fatty acids, or combinations thereof. Natural oils include, but are not limited to, Arachis oil (peanut oil; groundnut oil), Babassu oil, Coconut oil, Cottonseed oil, Grapeseed oil, Maize oil (corn oil), Mustard seed oil, Palm kernel oil, Palm oil, Palm olein (the liquid fraction derived from the fractionation of palm oil), Palm stearin (the high-melting fraction derived from the fractionation of palm oil), Rapeseed oil, Rapeseed oil-low erucic acid (low erucic acid turnip rape oil; low erucic acid colza oil; canola oil), Safflowerseed oil (safflower oil; carthamus oil; kurdee oil), Safflowerseed oil—high oleic acid (high oleic acid safflower oil; high oleic acid carthamus oil; high oleic acid kurdee oil), Sesameseed oil (sesame oil; gingelly oil; benne oil; ben oil; till oil; tillie oil), Soya bean oil (soybean oil), Sunflowerseed oil (sunflower oil), and Sunflowerseed oil-high oleic acid (high oleic acid sunflower oil). The feed stream derived from the natural oils comprises normal pa