Process for treating a feedstock comprising halides

Abstract

A process and a system for conversion of a hydrocarbonaceous feed comprising at least 10 ppmw and less than 10000 ppmw of one or more halides, and at least 20 ppmw and less than 10000 ppmw organically bound nitrogen, 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 and an amount of ammonia, said process including: a) separating in a first separation step at a first separation temperature the mixed product stream to provide an overhead stream and a bottoms stream, b) combining the overhead stream with an amount of wash water and c) separating in a second separation step the combined overhead stream and wash water in a non-polar stream of hydrocarbon product and a polar stream of wash water comprising ammonium halides.

Claims

1. A process for conversion of a hydrocarbonaceous feed comprising at least 10 ppmw and less than 10000 ppmw of one or more halides, and at least 20 ppmw and less than 10000 ppmw organically bound nitrogen, to a hydrocarbon product stream by hydrotreatment, under effective hydrotreatment conditions, in the presence of a material catalytically active in hydrotreatment and an amount of hydrogen, wherein said conversion provides a mixed product stream comprises an amount of ionic halides and an amount of ammonia, said process comprising the steps of a) separating in a stripping process at a first separation temperature the mixed product stream to provide an overhead stream and a bottoms stream, b) combining the overhead stream with an amount of wash water and c) separating in a second separation step the combined overhead stream and wash water in a non-polar stream of hydrocarbon product and a polar stream of wash water comprising ammonium halides, wherein the first separation temperature being above the precipitation temperature of the ammonium halides present in the mixed product stream.

2. A process according to claim 1 wherein said stripping process employs hydrogen, steam, methane or nitrogen as a stripping medium.

3. A process according to claim 1 wherein the temperature of said first separation step is above 280 C.

4. A process according to claim 1 wherein the temperature of said first separation step is below the temperature at which 30% of the mixed product stream boils.

5. A process according to claim 1, wherein said polar stream of wash water comprising ammonium halides is directed to a means of concentrating, to provide a stream of purified water and a stream of brine having a concentration of ammonium halides being more than 2 times and less than 100 times above that of the polar stream of wash water comprising ammonium halides.

6. A process for conversion of a raw feed stream rich in molecules comprising C, H, N and one or more halides, and optionally O, Si, and other elements, said process comprising: i. a step of thermal decomposition of said raw feed stream, to provide a precursor to a hydrocarbonaceous feed or a hydrocarbonaceous feed, ii. optionally a step of pre-treatment, purifying the precursor to hydrocarbona-ceous feed to provide the hydrocarbonaceous feed, and iii. 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 1, wherein the raw feed stream or the hydrocarbonaceous stream originates from a mixture rich in plastic, lignin, straw, lignocellulosic biomass, halide contaminated waste oils or aquatic biological material.

8. A process according to claim 1, followed by the step of directing the hydrocarbon product and/or the bottoms stream to a steam-cracking process.

9. A system for hydrotreatment of a hydrocarbonaceous stream comprising a) a hydrotreatment reactor containing a material catalytically active in hydrotreatment, said hydrotreatment reactor comprising an inlet for introducing a hydrogen enriched hydrocarbon stream and an outlet for withdrawing a first hydrocarbon product stream, b) a first means of separation having at least an inlet, an overhead outlet and a bottoms outlet, c) a means of mixing having two inlets and an outlet, d) a second means of separation, having an inlet and a liquid polar phase outlet, liquid non-polar phase outlet and gas phase outlet, wherein said outlet for withdrawing a first product stream is in fluid communication with the inlet of said first means of separation, wherein said overhead outlet is in fluid communication with the inlet of said first inlet of the means of mixing, wherein a source of water is in fluid communication with the second inlet of the means of mixing, wherein the outlet of the means of mixing is in fluid communication with the inlet of the second means of separation and wherein at least one of the bottoms outlet and the liquid non-polar phase out-let is in fluid communication with a hydrocarbon product outlet or a hydro-carbon fractionator inlet.

10. A system for hydrotreatment of a hydrocarbonaceous stream according to claim 9, where said first means of separation is a stripper further having a stripping medium inlet.

11. A system for hydrotreatment of a hydrocarbonaceous stream according to claim 9 further comprising a means of concentrating, having an inlet, a concentrated brine outlet and a purified water outlet, and the liquid polar phase outlet of the means of 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 second means of separation is configured for providing a hydrocarbon product.

Description

BRIEF DESCRIPTION OF THE FIGURE

[0067] FIG. 1 discloses a system for treating a hydrocarbon stream.

DETAILED DESCRIPTION OF THE FIGURE

[0068] 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.

[0069] The system of FIG. 1 comprises a sub-system for removing halides from a hydrocarbon stream before the hydrocarbon stream enters a final stripper and/or fractionation section.

[0070] FIG. 1 shows a hydrocarbon stream 2 containing a halide such as 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 in first reactor 16. 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 30 Barg to 150 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. 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.

[0071] 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, since hydrogenation reactions typically are very exothermic. 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 mixed 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 moderately in heat exchanger 32 to form a cooled product stream 30 having a temperature above the precipitation temperature of the mixed product stream. The cooled product 30 is directed to a hot stripper 40 where separation is aided by a stripping medium 42. 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.

[0072] 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 polar liquid 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.