Halide removal scrubbing systems for hydrocarbon streams.

Abstract

A halide removal cleaning system for absorbing halides from process gas in a process gas duct, the system comprising a cleaning water injection nozzle and anti-precipitation means disposed around the nozzle, the injection pipe and within the process duct.

Description

[Technical field]

[0001] The present invention relates to a system for the conversion of a hydrocarbonaceous feedstock where a portion of the feedstock being converted may solidify, in particular to a system for removing halides from a hydrocarbon stream containing one or more halides. [Background technology]

[0002] Refinery processes involve multiple treatments of hydrocarbon-rich streams to provide products in the form of gasoline, diesel, etc. Such treatments include hydrotreating, hydrocracking, fractionation and stripping, as well as intermediate heat exchange and removal of impurities.

[0003] Some of the hydrocarbon-rich streams to be processed in refineries contain halides (e.g., containing chlorine), which are undesirable in the product(s) and are also disadvantageous within the refinery plant due to corrosion problems within the plant's units.

[0004] In addition to the halides, other heteroatoms, such as nitrogen, are also present in the hydrocarbons being treated. During hydroprocessing, organically bound nitrogen can be released as ammonia. Ammonia and halides can react to form salts, such as ammonium chloride, which are solid at temperatures below 270°C. Precipitation of such salts can result in partial or complete blocking of the process lines and must therefore be avoided. It is therefore important to ensure that the process temperature is above 270°C.

[0005] Typically, hydrotreating reactions are exothermic, so that by heat exchange between the feed and the effluent it is possible to optimize the energy consumption of the process. However, when ammonia and halides are present, a problem in this respect is that in the feed / effluent heat exchanger, a feed temperature below 270° C. can result in cold zones in the heat exchanger, where, for example, ammonium chloride can precipitate.

[0006] In accordance with the present invention, a halide removal scrubbing system is described that is capable of absorbing halides from a process gas stream using scrubbing water injected into the process gas stream by an injector pipe and an injector nozzle.

[0007] WO2015 / 050635 (Citation 1) relates to a method for removing sulfur and halides from hydrocarbon streams by hydrotreating. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] WO2015 / 050635 Summary of the Invention [Problem to be solved by the invention]

[0009] The above document is silent about the presence of nitrogen in the intermediate stream and, in contrast to the present disclosure, explicitly recommends recovery of heat from the hydroprocessing product by heat exchange with cooling water, which would most likely cause salt precipitation if nitrogen is present. [Means for solving the problem]

[0010] The halide removal cleaning system of the present invention includes a process gas duct suitable for conducting a process gas containing a halide. The system also includes an injector pipe extending into the process gas duct. The injector pipe has a cleaning water inlet at a first end disposed outside the process gas duct and a cleaning water outlet with an injector nozzle at a second end of the injector pipe disposed within the process gas duct. The injector nozzle is adapted to spray cleaning water into the process gas in the process gas duct downstream of the injector nozzle to absorb halides from the process gas.

[0011] The halide removal cleaning system of the present invention, when used in a process gas duct containing a halide-containing process gas, produces NH 4 This has the advantage of ensuring that Cl does not precipitate on any surfaces. Thermal stresses in the pressure-bearing parts during injection are avoided by the machine design as explained in more detail with respect to the figures. Mixing of the wash water with the feed ensures washout of more than 99.9% of the HCl.

[0012] In one embodiment of the invention, the system comprises anti-deposition means arranged around at least a part of the injector pipe extending into the process gas duct. It should be understood that anti-deposition means are means that help to ensure that the surface of the injector pipe does not become cold relative to the process gas. If the surface of the injector pipe is relatively cold compared to the process gas around it, there is a risk that part of the process gas will deposit on the surface of the injector pipe, which may cause corrosion. The anti-deposition means may be, for example, a heating means or a thermal insulator.

[0013] In a further embodiment, the anti-deposition means is arranged around at least a portion of the injector nozzle. Providing the injector pipe and the injector nozzle with anti-deposition means is particularly beneficial, since these elements may otherwise present relatively cold surfaces on which there is a high risk of deposition of parts of the process gas.

[0014] The anti-deposition means may be in the form of insulation. In a further embodiment, the anti-deposition means may be an injector purge channel adapted to provide a purge flow that is relatively hot compared to the temperature of the wash water. In a further embodiment, the anti-deposition means may be heat tracing, such as a heated wire, i.e. an electrical wire capable of heating the surfaces of the injector nozzle and injector pipe when an electrical current is sent through the wire.

[0015] The effect of the insulation, purge channels, heat tracing and further anti-deposition measures is the avoidance of deposition on surfaces that would otherwise be relatively cool compared to the process gases.

[0016] In one embodiment of the invention, the process gas duct has an anticorrosive liner arranged on the inner surface of the process gas duct downstream of the injector nozzle. In one embodiment, the anticorrosive liner may be arranged adjacent to the inner surface of the process gas duct, leaving a gap between the inner surface of the process gas duct and the anticorrosive liner. This gap allows a purge fluid to flow between the anticorrosive liner and the process gas duct. The gap may be in the range of 0.2 to 50 mm in one embodiment. Furthermore, a seal may be provided between the anticorrosive liner and the process gas duct to prevent the process gas from entering the gap and for a controlled flow of the purge gas. Also, a purge fluid connection to the process gas duct downstream of the injector nozzle may be provided, which is adapted to purge a fluid into the gap.

[0017] In one embodiment of the invention, one or more mixers are positioned in the process gas duct downstream of the injector nozzle to provide mixing of the process gases.

[0018] In a further embodiment of the invention, not only one but multiple injector pipes and multiple injector nozzles are provided. Multiple injector pipes and -nozzles may be arranged in a single process gas duct, or there may be multiple process gas ducts, each with one or more injector pipes and -nozzles. The multiple process gas ducts are all upstream of the injector nozzle in a manifold setup. shared The process gas duct may be connected to the

[0019] As mentioned above, the above-described halide removal cleaning system can be used in a hydrotreating process.

[0020] Throughout this specification, the term "organic halides" refers to chemical compounds in which one or more carbon atoms are covalently linked to one or more halogen atoms (fluorine, chlorine, bromine, iodine or astatine - group 17 in current IUPAC terminology). "Inorganic halides" are compounds between halogen atoms and elements or radicals that are less electronegative (or more electropositive) than the halogens, resulting in fluoride, chloride, bromide, iodide or astatine compounds, but with the further restriction that carbon is not part of the compound.

[0021] The term "removing halide" is meant to include situations in which some of the halide present or all of the halide present is removed, and thus the term is not limited to situations in which a specific percentage of the halide present is removed.

[0022] The disclosed system may be found useful where the feedstock is a waste material containing halides, for example, for the direct hydroprocessing of plastic waste or the hydroprocessing of products from the pyrolysis of plastic waste. The feedstock may also be derived from algal lipids grown in salt water, or other biological feedstocks containing hydrocarbons and chlorides.

[0023] An example of such a halide removal cleaning system is described in more detail below with reference to the drawings. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 shows an overview of the halide removal cleaning system. [Diagram 2] FIG. 2 shows a detailed view of a portion of the halide removal system.

[0025] Position number 01. Process gas duct 02. Injector pipe 03. Injector nozzle 04. Injector connection flange 05. Insulation 06. Injector purge channel 07. Heat tracing 08. Duct Liner 09. Duct sealing 10. Mixing elements 11. Duct Purge

[0026] Detailed Description of the Drawings FIG. 1 shows a schematic of a halide removal cleaning system according to one embodiment of the present invention. In this embodiment, a manifold Solutions is used and several, in this case four, process gas ducts 01 are shared It should be understood that for simplicity, only one of the process gas ducts has a position number, and the other three process gas ducts contain similar components with similar position numbers. Within each process gas duct are: shared through the process gas duct of the shared upstream of the process gas duct and above shared Downstream of the process gas duct and within the process gas duct an injector pipe 02 is arranged. At a first end of the injector pipe an injector connection flange 04 provides a wash water inlet. At a second end of the injector pipe an injector nozzle 03 is arranged in fluid connection with the injector pipe and the injector connection flange. The injector nozzle is adapted to spray wash water into the process gas stream flowing within the process gas duct. Downstream of the injector nozzle and within the process gas duct a number of mixing elements 10 are arranged in succession to provide mixing of the process gases.

[0027] A portion of the halide removal cleaning system including the injector pipe and injector nozzle is shown in more detail in Figure 2. In this larger view, it can be seen that the injector pipe has both insulation 05 and heat tracing 07 to prevent deposition of the relatively hot process gases on the injector pipe with the relatively cooler cleaning water. The injector nozzle also has heat tracing, which further has an injector purge channel 06 around the nozzle to prevent deposition of the relatively hot process gases.

[0028] The process gas duct has a duct liner 08 disposed within the process gas duct adjacent to the inner surface of the duct, beginning a short distance upstream of the injector nozzle and extending downstream of the injector nozzle. The liner is disposed with a gap between the liner and the inner surface of the process gas duct, thereby allowing the flow of a duct purge 11 fluid. To control the flow of this purge fluid, a duct seal 09 is disposed between the liner and the inner surface of the process gas duct, at the beginning of the liner upstream of the liner. In addition, the present application relates to the invention described in the claims, but may also include the following as other aspects. 1. A halide removal scrubbing system with a process gas duct for a process gas containing hydrocarbons and halides, wherein an injector pipe extends into the process gas duct, the injector pipe having a scrubbing water inlet at a first end of the injector pipe arranged outside the process gas duct, and a scrubbing water outlet at a second end of the injector pipe with an injector nozzle adapted to spray scrubbing water into the process gas in the process gas duct downstream of the injector nozzle. 2. The halide removal cleaning system according to claim 1, further comprising anti-deposition means disposed around at least a portion of said injector pipe extending into the process gas duct. 3. The halide removal cleaning system according to claim 1 or 2, further comprising an anti-deposition means disposed around at least a portion of said injector nozzle. 4. The halide removal cleaning system according to claim 2 or 3, wherein the anti-precipitation means is a thermal insulating material. 5. The halide removal cleaning system according to claim 2 or 3, wherein said anti-precipitation means is an injector purge channel adapted to provide an injector purge fluid that is relatively hot compared to the temperature of the cleaning water. 6. The halide removal cleaning system according to claim 2 or 3, wherein the anti-deposition means is an electric heating wire. 7. The halide removal cleaning system according to any one of claims 1 to 6, wherein the process gas duct has a corrosion-resistant liner disposed on the inner surface of the process gas duct downstream of the injector nozzle. 8. A halide removal cleaning system according to any one of claims 1 to 7, wherein a corrosion liner is positioned within the process gas duct, adjacent to the inner surface of the process gas duct downstream of the injector nozzle, with a gap between the inner surface of the process gas duct and the corrosion liner to allow duct purge fluid between the corrosion liner and the process gas duct. 9. A halide removal cleaning system according to any one of claims 1 to 8, wherein a corrosion liner is positioned within the process gas duct, adjacent to the inner surface of the process gas duct downstream of the injector nozzle, with a gap of 0.2 to 50 mm between the inner surface of the process gas duct and the corrosion liner to allow duct purge fluid between the corrosion liner and the process gas duct. 10. The halide removal cleaning system according to claim 8 or 9, further comprising a seal between the corrosion protection liner and the process gas duct, and a duct purge fluid connection to the process gas duct downstream of the injector nozzle adapted to purge fluid into a gap between the corrosion protection liner and the process gas duct. 11. A halide removal cleaning system as described in any one of claims 8, 9 or 10 above, including a duct purge fluid consumption monitoring system adapted to provide an alarm output if duct purge fluid consumption exceeds a preset value. 12. The halide removal cleaning system according to any one of claims 1 to 11, further comprising at least one fluid mixer element disposed in the process gas duct downstream of the injector nozzle. 13. A halide removal cleaning system according to any one of 1 to 12 above, comprising a plurality of injector pipes and a plurality of injector nozzles. 14. A halide removal cleaning system according to any one of claims 1 to 13, comprising a plurality of process gas ducts and a plurality of injector pipes and injector nozzles; a shared process gas duct upstream of the injector nozzles, and a plurality of process gas ducts downstream of each of the injector nozzles. 15. Use of the halide removal cleaning system according to any one of 1 to 14 above in a hydrotreating process.

Claims

1. A halide removal scrubbing system for a process gas containing hydrocarbons and halides, comprising a process gas duct, an injector pipe extending into the process gas duct, the injector pipe having a scrubbing water inlet for absorbing halides from the process gas at a first end of the injector pipe arranged outside the process gas duct, and a scrubbing water outlet at a second end of the injector pipe, the scrubbing water outlet having an injector nozzle adapted to spray the scrubbing water into the process gas in the process gas duct downstream of the injector nozzle; and an anti-deposition means disposed around at least a portion of the injector pipe extending into the process gas duct, the anti-deposition means being a thermal insulator or a heating wire. Halide removal cleaning system.

2. 2. The halide removal cleaning system of claim 1, further comprising an anti-deposition means disposed around at least a portion of said injector nozzle, said anti-deposition means being insulation or a heating wire.

3. 3. The halide removal cleaning system of claim 1 or 2, wherein the process gas duct has a corrosion-resistant liner disposed on the inner surface of the process gas duct downstream of the injector nozzle.

4. 4. The halide removal cleaning system according to claim 1, wherein a corrosion protection liner is disposed within the process gas duct, downstream of the injector nozzle and adjacent to an inner surface of the process gas duct, with a gap between the inner surface of the process gas duct and the corrosion protection liner to allow duct purge fluid between the corrosion protection liner and the process gas duct.

5. 5. The halide removal cleaning system according to claim 1, wherein a corrosion resistant liner is disposed within the process gas duct downstream of the injector nozzle and adjacent to an inner surface of the process gas duct with a gap of 0.2 to 50 mm between the inner surface of the process gas duct and the corrosion resistant liner to allow duct purge fluid between the corrosion resistant liner and the process gas duct.

6. 6. The halide removal cleaning system of claim 4 or 5, further comprising a seal between the anticorrosive liner and the process gas duct, and a duct purge fluid connection to the process gas duct downstream of the injector nozzle adapted to purge a fluid into a gap between the anticorrosive liner and the process gas duct.

7. 7. The halide removal cleaning system of claim 4, 5 or 6, including a duct purge fluid consumption monitoring system adapted to provide an alarm output if duct purge fluid consumption exceeds a preset value.

8. 8. The halide removal cleaning system according to claim 1, further comprising at least one mixer for mixing product gases, disposed in the process gas duct downstream of the injector nozzle.

9. 9. The halide removal cleaning system according to claim 1, comprising a plurality of said injector pipes and a plurality of said injector nozzles, wherein there is a single said process gas duct, said single process gas duct having said plurality of injector pipes and said plurality of injector nozzles, or there are a plurality of said process gas ducts, each of said process gas ducts having one or more of said injector pipes and injector nozzles.

10. 10. The halide removal cleaning system according to claim 1, further comprising: a plurality of said process gas ducts, a plurality of said injector pipes, and a plurality of said injector nozzles; a common process gas duct upstream of said injector nozzles to which all of said process gas ducts are connected, and each of said injector pipes is disposed through said common process gas duct and within each of said process gas ducts upstream of said common process gas duct and downstream of said common process gas duct.

11. The halide removal cleaning system of claim 10, wherein all of the plurality of process gas ducts are connected to the shared process gas duct at a manifold.

12. Use of the halide removal cleaning system according to any one of claims 1 to 11 in a hydrotreating process.

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