PROCESS FOR TREATING A FEEDSTOCK COMPRISING HALIDES

Abstract

A process for conversion of a hydro-carbonaceous feed including ionic halides to a hydrocarbon product stream by hydrotreatment, wherein the stream is combined with wash water, the weight ratio between wash water and hydrocarbon product stream water is between 1:10 and 10:1, wherein the combined hydrocarbon product stream and wash water are separated in a non-polar stream of hydrocarbon product and a polar stream of wash water including ionic halides, such that from 50% of the ionic halides are transferred from the hydrocarbon product stream to the polar stream of wash water including ionic halides, wherein the polar stream of wash water is directed to a means of concentrating, to provide a stream of purified water and a stream of brine having a concentration of ionic halides being more than 2 times and less than 100 times above that of the polar stream of waste water including ionic halides.

Claims

1. A process for conversion of a hydrocarbonaceous feed comprising at least 20 ppmw halides, to a hydrocarbon product stream by hydrotreatment, in the presence of a material catalytically active in hydrotreatment and an amount of hydrogen, wherein said hydrocarbon product stream comprises an amount of ionic halides, wherein said hydrocarbon product stream is combined with an amount of wash water, wherein the weight ratio between wash water and hydrocarbon product stream water is above 1:10 and below 10:1, and wherein the combined hydrocarbon product stream and wash water are separated in a non-polar stream of hydrocarbon product and a polar stream of wash water comprising ionic halides, such that from 50% of said ionic halides are transferred from said hydrocarbon product stream to the polar stream of wash water comprising ionic halides, wherein polar stream of wash water comprising ionic halides being directed to a means of concentrating, to provide a stream of purified water and a stream of brine having a concentration of ionic halides being more than 2 times and less than 100 times above that of the polar stream of wash water comprising ionic halides.

2. A process according to claim 1, wherein said means of concentrating is an evaporator, heating the polar stream of wash water comprising ionic halides, to evaporate an amount of water, constituting said stream of purified water.

3. A process according to claim 2, wherein said evaporator is a falling film evaporator configured for flowing the polar stream of wash water comprising ionic halides over a heated surface, and further configured for collecting the evaporated water and directing it as the stream of purified water.

4. A process according to claim 1, wherein said means of concentration is a membrane separator or a reverse osmosis separator.

5. A process according to claim 1, wherein the pH of said polar stream of wash water comprising ionic halides is adjusted to a value between 6.5 and 9 by addition of an amount of base or acid to either the stream of wash water or the polar stream of wash water comprising ionic halides.

6. A process for conversion of a raw feed stream rich in molecules comprising C, H and a halide, and optionally O, N, Si, and other elements, said process involving a. a step of thermal decomposition of said raw feed stream, to provide a precursor to a hydrocarbonaceous feed or a hydrocarbonaceous feed, b. optionally a step of pre-treatment, purifying the precursor to hydrocarbonaceous feed to provide a hydrocarbonaceous feed c. a hydrotreatment step for converting the hydrocarbonaceous feed in the presence of hydrogen, in accordance with claim 1, to provide a hydrocarbon product stream.

7. A process according to claim 6, followed by the step of directing the hydrocarbon product stream to a steam-cracking process.

8. A system for hydrotreatment of a hydrocarbonaceous stream comprising a. a hydrotreament reactor containing a material catalytically active in hydrotreament, said hydrotreament reactor comprising an inlet for inletting a hydrogen enriched hydrocarbon stream and an outlet for outletting a first product stream, b. a means of mixing having two inlets and an outlet, c. a means of phase separation, having an inlet and a liquid polar phase outlet, liquid nonpolar phase outlet and gas phase outlet, d. a means of concentrating, having an inlet, a concentrated brine outlet and a purified water outlet, wherein said outlet for outletting a first product stream is in fluid communication with a first inlet of the means of mixing, wherein the outlet of the means of mixing is in fluid communication with the inlet of the means of phase separation, and the liquid polar phase outlet of the means of phase separation is in fluid communication with the inlet of the means of concentrating, wherein the purified water outlet of the means of concentrating is in fluid communication with a second inlet of the means of mixing optionally in combination with a further source of purified water and wherein the liquid non-polar phase outlet of the means of phase separation is configured for providing a hydrocarbon product.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0037] FIG. 1 discloses a system for treating a hydrocarbon stream.

DETAILED DESCRIPTION OF THE FIGURE

[0038] FIG. 1 discloses a system for treating hydrocarbons. Even though some heat exchange units, pumps and compressors are shown in FIG. 1, further pumps, heaters, valves and other process equipment may be part of the system of FIG. 1.

[0039] The system of FIG. 1 comprises a sub-system for removing halides from a hydrocarbon stream before the hydrocarbon stream enters a stripper and/or fractionation section.

[0040] FIG. 1 shows a hydrocarbon stream 2 containing chlorine. This stream is optionally preheated, before being combined with a hydrogen rich gas stream 6 to a hydrogen enriched hydrocarbon stream 10 in order to ensure the provision of the required hydrogen for the hydrogenation of di-olefins. The hydrogen enriched hydrocarbon stream 10 is heated in heat exchanger 12, and optionally by further heating such as a fired heater to form a heated hydrogen enriched hydrocarbon stream 14. The first reactor 16 is optional, but may have operating conditions at a pressure of about 30 Barg and a temperature of about 180° C., suitable for hydrogenation of di-olefins. The first reactor 16 contains a material catalytically active in olefin saturation and hydro-dehalogenation.

[0041] Within the first reactor 16, the heated hydrogen enriched hydrocarbon stream 14 reacts at the presence of the catalytically active material, rendering a first hydrogenated product stream 18.

[0042] The first hydrogenated product stream 18 is heated, e.g. in a fired heater 20, and transferred as a heated first hydrogenated product stream 22 to a second reactor 24 where it reacts at the presence of a second catalytically active material. Often quench gas 26 is provided to the second reactor to control the temperature. The first and second catalytically active material may be identical or different from each other and will typically comprise a combination of sulfided base metals such as molybdenum or tungsten promoted by nickel or cobalt supported on a refractory support such as alumina or silica. Typically, the reaction over the first catalytically active material is dominated by saturation of di-olefins, whereas the reaction over the second catalytically active material is dominated by saturation of mono-olefins and hydro-dehalogenation of halide-hydrocarbons, but also hydrodesulfurization, hydrodenitrogenation and hydrodeoxygenation may take place in the second reactor 24 (depending on the composition of the feedstock). Therefore, the hot product stream 28 may comprise hydrocarbons, H.sub.2O, H.sub.2S, NH.sub.3 and HCl, which may be withdrawn by washing and separation. The hot product stream 28 is cooled to form a cooled product stream 30, in heat exchanger 32. The cooled product 30 is directed to a hot stripper 40 where separation is aided by a stripping medium 42, in which the cooled product 30 is split in a gas product fraction 44 and a liquid product fraction 46. The gas product fraction 44 is combined with a stream of purified water 50, providing a mixed stream 52 and cooled in cooler 54, providing a three phase stream 56, which is separated in three-way separator 58, into a light hydrocarbon stream 60, a contaminated water stream 62 and a hydrogen rich gas stream 66. The hydrogen rich gas stream 66 is directed to a recycle compressor 68 and directed as quench gas 26 for the second reactor 24 and as stripping medium 42 for the hot stripper 40, as well as recycle gas 8 to be combined with make-up hydrogen gas 4, forming hydrogen rich gas 6.

[0043] The light hydrocarbon stream 60 exiting the three-phase separator 58 enters a second stripper 48 to further separate liquid and gaseous components, with the aid of a stripping medium 72. The light ends output 78 from the second stripper 48 is cooled in cooler 80 and directed as a cooled light ends fraction 82 to a further three-phase separator 84 arranged to separate an off-gas fraction 86 from a water fraction 88 and a hydrocarbon liquid fraction 92. The hydrocarbon liquid fraction 92 from the further three-phase separator 84 is recycled to the second stripper 48, the polar liquid fraction 88 can be combined with the contaminated water stream 62 and be directed to a means of concentrating 96, from which a stream of concentrated brine 98, rich in e.g. NH.sub.4Cl, as well as a stream of purified water 50, comprising a low amount of impurities such as NH.sub.4Cl, are withdrawn. The purified water may, typically together with an added amount of water, be added as pure wash water 50.