Hydrotreating Coker Kerosene With A Separate Trim Reactor (United States Patent Application 20150210939 – UOP)

CATEGORY: KEROSENE
Hydrotreating Coker Kerosene With A Separate Trim Reactor (United States Patent Application 20150210939 – UOP)
July 30, 2015
Abstract
A process for hydrotreating coker kerosene is described. Instead of a post treat reactor, a smaller trim reactor zone which operates at a lower pressure than the post treat reactor is used downstream of the product stripper. The trim reactor uses a noble metal catalyst to reduce the BI of the stripped product to less than about 150, and desirably in the range of about 50 to about 100.
BACKGROUND OF THE INVENTION
[0001] The delayed coker process converts the residue from heavy, high sulfur crudes into transportation fuels. The kerosene stream from the coker process is known as coker kerosene. It comprises hydrocarbons in the range of C9 to C20 and has a boiling point in the range of about 140.degree. C. to about 320.degree. C. It has a T5 point of 150.degree. C. and a T95 point of 295.degree. C. measured according to ASTM D86.
[0002] Coker kerosene contains high levels of sulfur (e.g., about 2 to about 5 wt %) and nitrogen (e.g., about 600-1000 wppm). Coker kerosene has to be hydrotreated to reduce the levels of sulfur and nitrogen before it can be treated in a separation unit, such as Molex.TM. to separate the n-paraffins from the non-normal hydrocarbons. The feed specifications for the Molex.TM. process include a sulfur level of less than 1 wppm, and a maximum nitrogen level of 0.5 wppm. Kerosene also contains olefins, and the olefins are saturated during the hydrotreating process. Another feed specification for the Molex.TM. process is a bromine index (BI) in the range of less than about 150.
[0003] In order to meet the sulfur, nitrogen, and BI specifications for a coker kerosene feed, severe hydrotreating at pressure in the range of about 7.6 MPa(g) (1100 psig) to about 8.3 MPa(g) (1200 psig) is required.
[0004] However, it is preferable to hydrotreat at the lowest possible pressure to reduce the capital cost of the unit. The sulfur and nitrogen specifications can be met at lower pressures, e.g., in the range of about 4.8 MPa(g) (700 psig) to about 6.2 MPa(g) (900 psig). However, the BI specification cannot be met by hydrotreating at that pressure.
[0005] Normally, a post treat reactor loaded with a hydrotreating catalyst is installed downstream of the main hydrotreating reactor to obtain the required BI. The post treat reactor has to operate at sufficiently high pressure and catalyst volume to meet the BI. Due to equilibrium limitations, the temperature of the post treat reactor needs to be in the range of about 250.degree. C. and 350.degree. C. to ensure that the required olefin saturation is obtained to meet BI requirement.
[0006] Even with the post treat reactor, it is not always possible to obtain BI values in the range of 50-100.
[0007] There is a need for lower cost processes to upgrade coker kerosene.
SUMMARY OF THE INVENTION
[0008] One aspect of the invention is a process for hydrotreating coker kerosene. In one embodiment, the process includes hydrotreating a coker kerosene feed stream in a hydrotreating zone in the presence of a hydrotreating catalyst to form a mixture of normal paraffins and non-normal hydrocarbons, the coker kerosene feed stream having a level of sulfur of at least about 1.0 wt %, and a level of nitrogen of at least about 500 wppm, a level of sulfur in the mixture being less than 1 wppm and a level of nitrogen in the mixture being 0.5 wppm or less. The mixture is separated in a gas-liquid separation zone into a vapor stream and a liquid stream, and the liquid stream is introduced into a stripper zone. The bottoms stream from the stripper zone is reacted in a trim reactor zone in the presence of a noble metal catalyst to reduce a bromine index of the bottoms stream, the trim reaction zone operating at a pressure of about 2.1 MPa(g) (300 psig) to about 6.2 MPa(g) (900 psig);. The effluent from the trim reactor zone has a level of sulfur of less than 1 wppm, a level of nitrogen of 0.5 wppm or less, and a bromine index of about 150 or less.
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Methods for producing linear alkylbenzenes, paraffins, and olefins from natural oils and kerosene (UOP)

PATENT
Methods for producing linear alkylbenzenes, paraffins, and olefins from natural oils and kerosene (UOP)
Publication number
US8502005 B1
Application number
US 13/427,718
Publication date
Aug 6, 2013
Inventors
Andrea G. Bozzano, Stephen Wayne Sohn
Original Assignee
Uop Llc
Abstract
A method for producing a linear paraffin product from natural oil and kerosene includes providing a first feed stream comprising kerosene, pre-fractionating the first feed stream to produce a heart cut paraffin stream comprising paraffins in a heart cut range, and combining the heart cut paraffin stream with a second feed stream comprising natural oil to form a combined stream. The method further includes deoxygenating the natural oil and fractionating the combined stream to remove paraffins that are heavier than the heart cut range.
FIELD OF THE INVENTION
The present invention relates generally to methods for producing renewable detergent compounds, and more particularly relates to methods for producing linear alkylbenzenes, paraffins, and olefins from natural oils and kerosene.
BACKGROUND OF THE INVENTION
While detergents made utilizing linear alkylbenzene-, paraffin-, and olefin-based surfactants are biodegradable, processes for creating linear alkylbenzenes, paraffins, and olefins are not based on renewable sources. Specifically, linear alkylbenzenes, paraffins, and olefins are traditionally produced from kerosene extracted from the earth. Due to the growing environmental concerns over fossil fuel extraction and economic concerns over exhausting fossil fuel deposits, there is a demand for incorporating alternate feed sources with the traditional kerosene feed source for producing biodegradable surfactants for use in detergents and in other industries.
Accordingly, it is desirable to provide methods for producing linear alkylbenzenes, paraffins, and olefins from a feed source that includes natural oils, i.e., oils that are not extracted from the earth, in addition to kerosene. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, when taken in conjunction with the accompanying drawing and this background of the invention.
SUMMARY OF THE INVENTION
Methods for producing a linear alkylbenzene, paraffin, or olefin product from a natural oil and kerosene feed source are provided herein. In accordance with an exemplary embodiment, a method for producing a linear paraffin product from natural oil and kerosene includes providing a first feed stream comprising kerosene, pre-fractionating the first feed stream to produce a heart cut paraffin stream comprising paraffins in a heart cut range, and combining the heart cut paraffin stream with a second feed stream comprising natural oil to form a combined stream. The method further includes deoxygenating the natural oil and fractionating the combined stream to remove paraffins that are heavier than the heart cut range.
In another exemplary embodiment, a method for producing a linear olefin product from natural oil and kerosene includes providing a first feed stream comprising kerosene, pre-fractionating the first feed stream to produce a first heart cut paraffin stream comprising paraffins in a heart cut range, and combining the first heart cut paraffin stream with a second feed stream comprising natural oil to form a combined stream. The method further includes deoxygenating the natural oil, fractionating the combined stream and removing paraffins that are heavier than the heart cut range to form a second heart cut paraffin stream, and dehydrogenating the second heart cut paraffin stream to form a stream comprising olefins.
In accordance with yet another exemplary embodiment, a method for producing a linear alkylbenzene product from natural oil and kerosene includes providing a first feed stream comprising kerosene, pre-fractionating the first feed stream to produce a first heart cut paraffin stream comprising paraffins in a heart cut range, and combining the first heart cut paraffin stream with a second feed stream comprising natural oil to form a combined stream. The method further includes deoxygenating the natural oil, fractionating the combined stream and removing paraffins that are heavier than the heart cut range to form a second heart cut paraffin stream, dehydrogenating the second heart cut paraffin stream to form a stream comprising olefins, and alkylating the stream comprising olefins with a third feed stream comprising benzene to form a stream comprising alkylbenzenes.
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